Merge branch 'main' into file-browser

221 files changed, 2180 insertions, 2821 deletions

diff --git a/src/app_console/CMakeLists.txt b/src/app_console/CMakeLists.txt
deleted file mode 100644
index 1a2ae8d6..00000000
--- a/src/app_console/CMakeLists.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-# Copyright 2023 jacqueline <me@jacqueline.id.au>
-#
-# SPDX-License-Identifier: GPL-3.0-only
-
-idf_component_register(
-  SRCS "app_console.cpp"
-  INCLUDE_DIRS "include"
-  REQUIRES "dev_console" "events" "database")
-target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/audio/CMakeLists.txt b/src/audio/CMakeLists.txt
deleted file mode 100644
index 8ed5efbb..00000000
--- a/src/audio/CMakeLists.txt
+++ /dev/null
@@ -1,14 +0,0 @@
-# Copyright 2023 jacqueline <me@jacqueline.id.au>
-#
-# SPDX-License-Identifier: GPL-3.0-only
-
-idf_component_register(
-  SRCS "audio_decoder.cpp" "fatfs_audio_input.cpp" "i2s_audio_output.cpp"
-  "track_queue.cpp" "audio_fsm.cpp" "audio_converter.cpp" "resample.cpp"
-  "fatfs_source.cpp" "bt_audio_output.cpp" "readahead_source.cpp"
-  "audio_source.cpp"
-  INCLUDE_DIRS "include"
-  REQUIRES "codecs" "drivers" "cbor" "result" "tasks" "span" "memory" "tinyfsm"
-  "database" "system_fsm" "speexdsp" "millershuffle" "libcppbor")
-
-target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/audio/audio_decoder.cpp b/src/audio/audio_decoder.cpp
deleted file mode 100644
index 90c69c16..00000000
--- a/src/audio/audio_decoder.cpp
+++ /dev/null
@@ -1,148 +0,0 @@
-/*
- * Copyright 2023 jacqueline <me@jacqueline.id.au>
- *
- * SPDX-License-Identifier: GPL-3.0-only
- */
-
-#include "audio_decoder.hpp"
-#include <stdint.h>
-
-#include <cstdint>
-#include <cstdlib>
-
-#include <algorithm>
-#include <cmath>
-#include <cstddef>
-#include <cstdint>
-#include <cstring>
-#include <deque>
-#include <memory>
-#include <variant>
-
-#include "cbor.h"
-#include "esp_err.h"
-#include "esp_heap_caps.h"
-#include "esp_log.h"
-#include "freertos/portmacro.h"
-#include "freertos/projdefs.h"
-#include "freertos/queue.h"
-#include "freertos/ringbuf.h"
-#include "i2s_dac.hpp"
-#include "span.hpp"
-
-#include "audio_converter.hpp"
-#include "audio_events.hpp"
-#include "audio_fsm.hpp"
-#include "audio_sink.hpp"
-#include "audio_source.hpp"
-#include "codec.hpp"
-#include "event_queue.hpp"
-#include "fatfs_audio_input.hpp"
-#include "sample.hpp"
-#include "tasks.hpp"
-#include "track.hpp"
-#include "types.hpp"
-#include "ui_fsm.hpp"
-
-namespace audio {
-
-[[maybe_unused]] static const char* kTag = "audio_dec";
-
-static constexpr std::size_t kCodecBufferLength =
-    drivers::kI2SBufferLengthFrames * sizeof(sample::Sample);
-
-auto Decoder::Start(std::shared_ptr<IAudioSource> source,
-                    std::shared_ptr<SampleConverter> sink) -> Decoder* {
-  Decoder* task = new Decoder(source, sink);
-  tasks::StartPersistent<tasks::Type::kAudioDecoder>([=]() { task->Main(); });
-  return task;
-}
-
-Decoder::Decoder(std::shared_ptr<IAudioSource> source,
-                 std::shared_ptr<SampleConverter> mixer)
-    : source_(source), converter_(mixer), codec_(), current_format_() {
-  ESP_LOGI(kTag, "allocating codec buffer, %u KiB", kCodecBufferLength / 1024);
-  codec_buffer_ = {
-      reinterpret_cast<sample::Sample*>(heap_caps_calloc(
-          kCodecBufferLength, sizeof(sample::Sample), MALLOC_CAP_DMA)),
-      kCodecBufferLength};
-}
-
-void Decoder::Main() {
-  for (;;) {
-    if (source_->HasNewStream() || !stream_) {
-      std::shared_ptr<TaggedStream> new_stream = source_->NextStream();
-      if (new_stream && BeginDecoding(new_stream)) {
-        stream_ = new_stream;
-      } else {
-        continue;
-      }
-    }
-
-    if (ContinueDecoding()) {
-      stream_.reset();
-    }
-  }
-}
-
-auto Decoder::BeginDecoding(std::shared_ptr<TaggedStream> stream) -> bool {
-  // Ensure any previous codec is freed before creating a new one.
-  codec_.reset();
-  codec_.reset(codecs::CreateCodecForType(stream->type()).value_or(nullptr));
-  if (!codec_) {
-    ESP_LOGE(kTag, "no codec found for stream");
-    return false;
-  }
-
-  auto open_res = codec_->OpenStream(stream, stream->Offset());
-  if (open_res.has_error()) {
-    ESP_LOGE(kTag, "codec failed to start: %s",
-             codecs::ICodec::ErrorString(open_res.error()).c_str());
-    return false;
-  }
-  stream->SetPreambleFinished();
-  current_sink_format_ = IAudioOutput::Format{
-      .sample_rate = open_res->sample_rate_hz,
-      .num_channels = open_res->num_channels,
-      .bits_per_sample = 16,
-  };
-
-  std::optional<uint32_t> duration;
-  if (open_res->total_samples) {
-    duration = open_res->total_samples.value() / open_res->num_channels /
-               open_res->sample_rate_hz;
-  }
-
-  converter_->beginStream(std::make_shared<TrackInfo>(TrackInfo{
-      .tags = stream->tags(),
-      .uri = stream->Filepath(),
-      .duration = duration,
-      .start_offset = stream->Offset(),
-      .bitrate_kbps = open_res->sample_rate_hz,
-      .encoding = stream->type(),
-      .format = *current_sink_format_,
-  }));
-
-  return true;
-}
-
-auto Decoder::ContinueDecoding() -> bool {
-  auto res = codec_->DecodeTo(codec_buffer_);
-  if (res.has_error()) {
-    converter_->endStream();
-    return true;
-  }
-
-  if (res->samples_written > 0) {
-    converter_->continueStream(codec_buffer_.first(res->samples_written));
-  }
-
-  if (res->is_stream_finished) {
-    converter_->endStream();
-    codec_.reset();
-  }
-
-  return res->is_stream_finished;
-}
-
-}  // namespace audio
diff --git a/src/audio/fatfs_audio_input.cpp b/src/audio/fatfs_audio_input.cpp
deleted file mode 100644
index 29d32390..00000000
--- a/src/audio/fatfs_audio_input.cpp
+++ /dev/null
@@ -1,161 +0,0 @@
-/*
- * Copyright 2023 jacqueline <me@jacqueline.id.au>
- *
- * SPDX-License-Identifier: GPL-3.0-only
- */
-
-#include "fatfs_audio_input.hpp"
-
-#include <algorithm>
-#include <climits>
-#include <cstddef>
-#include <cstdint>
-#include <functional>
-#include <future>
-#include <memory>
-#include <mutex>
-#include <string>
-#include <variant>
-
-#include "esp_heap_caps.h"
-#include "esp_log.h"
-#include "ff.h"
-#include "freertos/portmacro.h"
-#include "freertos/projdefs.h"
-#include "readahead_source.hpp"
-#include "span.hpp"
-
-#include "audio_events.hpp"
-#include "audio_fsm.hpp"
-#include "audio_source.hpp"
-#include "codec.hpp"
-#include "event_queue.hpp"
-#include "fatfs_source.hpp"
-#include "future_fetcher.hpp"
-#include "spi.hpp"
-#include "tag_parser.hpp"
-#include "tasks.hpp"
-#include "track.hpp"
-#include "types.hpp"
-
-[[maybe_unused]] static const char* kTag = "SRC";
-
-namespace audio {
-
-FatfsAudioInput::FatfsAudioInput(database::ITagParser& tag_parser,
-                                 tasks::WorkerPool& bg_worker)
-    : IAudioSource(),
-      tag_parser_(tag_parser),
-      bg_worker_(bg_worker),
-      new_stream_mutex_(),
-      new_stream_(),
-      has_new_stream_(false) {}
-
-FatfsAudioInput::~FatfsAudioInput() {}
-
-auto FatfsAudioInput::SetPath(std::optional<std::string> path) -> void {
-  if (path) {
-    SetPath(*path);
-  } else {
-    SetPath();
-  }
-}
-
-auto FatfsAudioInput::SetPath(const std::string& path,uint32_t offset) -> void {
-  std::lock_guard<std::mutex> guard{new_stream_mutex_};
-  if (OpenFile(path, offset)) {
-    has_new_stream_ = true;
-    has_new_stream_.notify_one();
-  }
-}
-
-auto FatfsAudioInput::SetPath() -> void {
-  std::lock_guard<std::mutex> guard{new_stream_mutex_};
-  new_stream_.reset();
-  has_new_stream_ = true;
-  has_new_stream_.notify_one();
-}
-
-auto FatfsAudioInput::HasNewStream() -> bool {
-  return has_new_stream_;
-}
-
-auto FatfsAudioInput::NextStream() -> std::shared_ptr<TaggedStream> {
-  while (true) {
-    has_new_stream_.wait(false);
-
-    {
-      std::lock_guard<std::mutex> guard{new_stream_mutex_};
-      if (!has_new_stream_.exchange(false)) {
-        // If the new stream went away, then we need to go back to waiting.
-        continue;
-      }
-
-      if (new_stream_ == nullptr) {
-        continue;
-      }
-
-      auto stream = new_stream_;
-      new_stream_ = nullptr;
-      return stream;
-    }
-  }
-}
-
-auto FatfsAudioInput::OpenFile(const std::string& path,uint32_t offset) -> bool {
-  ESP_LOGI(kTag, "opening file %s", path.c_str());
-
-  auto tags = tag_parser_.ReadAndParseTags(path);
-  if (!tags) {
-    ESP_LOGE(kTag, "failed to read tags");
-    return false;
-  }
-  if (!tags->title()) {
-    tags->title(path);
-  }
-
-  auto stream_type = ContainerToStreamType(tags->encoding());
-  if (!stream_type.has_value()) {
-    ESP_LOGE(kTag, "couldn't match container to stream");
-    return false;
-  }
-
-  std::unique_ptr<FIL> file = std::make_unique<FIL>();
-  FRESULT res;
-
-  {
-    auto lock = drivers::acquire_spi();
-    res = f_open(file.get(), path.c_str(), FA_READ);
-  }
-
-  if (res != FR_OK) {
-    ESP_LOGE(kTag, "failed to open file! res: %i", res);
-    return false;
-  }
-
-  auto source =
-      std::make_unique<FatfsSource>(stream_type.value(), std::move(file));
-  new_stream_.reset(new TaggedStream(tags, std::move(source), path, offset));
-  return true;
-}
-
-auto FatfsAudioInput::ContainerToStreamType(database::Container enc)
-    -> std::optional<codecs::StreamType> {
-  switch (enc) {
-    case database::Container::kMp3:
-      return codecs::StreamType::kMp3;
-    case database::Container::kWav:
-      return codecs::StreamType::kWav;
-    case database::Container::kOgg:
-      return codecs::StreamType::kVorbis;
-    case database::Container::kFlac:
-      return codecs::StreamType::kFlac;
-    case database::Container::kOpus:
-      return codecs::StreamType::kOpus;
-    case database::Container::kUnsupported:
-    default:
-      return {};
-  }
-}
-
-}  // namespace audio
diff --git a/src/audio/include/audio_decoder.hpp b/src/audio/include/audio_decoder.hpp
deleted file mode 100644
index 89f0f43c..00000000
--- a/src/audio/include/audio_decoder.hpp
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Copyright 2023 jacqueline <me@jacqueline.id.au>
- *
- * SPDX-License-Identifier: GPL-3.0-only
- */
-
-#pragma once
-
-#include <cstdint>
-#include <memory>
-
-#include "audio_converter.hpp"
-#include "audio_events.hpp"
-#include "audio_sink.hpp"
-#include "audio_source.hpp"
-#include "codec.hpp"
-#include "track.hpp"
-#include "types.hpp"
-
-namespace audio {
-
-/*
- * Handle to a persistent task that takes bytes from the given source, decodes
- * them into sample::Sample (normalised to 16 bit signed PCM), and then
- * forwards the resulting stream to the given converter.
- */
-class Decoder {
- public:
-  static auto Start(std::shared_ptr<IAudioSource> source,
-                    std::shared_ptr<SampleConverter> converter) -> Decoder*;
-
-  auto Main() -> void;
-
-  Decoder(const Decoder&) = delete;
-  Decoder& operator=(const Decoder&) = delete;
-
- private:
-  Decoder(std::shared_ptr<IAudioSource> source,
-          std::shared_ptr<SampleConverter> converter);
-
-  auto BeginDecoding(std::shared_ptr<TaggedStream>) -> bool;
-  auto ContinueDecoding() -> bool;
-
-  std::shared_ptr<IAudioSource> source_;
-  std::shared_ptr<SampleConverter> converter_;
-
-  std::shared_ptr<codecs::IStream> stream_;
-  std::unique_ptr<codecs::ICodec> codec_;
-
-  std::optional<codecs::ICodec::OutputFormat> current_format_;
-  std::optional<IAudioOutput::Format> current_sink_format_;
-
-  cpp::span<sample::Sample> codec_buffer_;
-};
-
-}  // namespace audio
diff --git a/src/audio/include/fatfs_audio_input.hpp b/src/audio/include/fatfs_audio_input.hpp
deleted file mode 100644
index 10b7433e..00000000
--- a/src/audio/include/fatfs_audio_input.hpp
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
- * Copyright 2023 jacqueline <me@jacqueline.id.au>
- *
- * SPDX-License-Identifier: GPL-3.0-only
- */
-
-#pragma once
-
-#include <cstddef>
-#include <cstdint>
-#include <future>
-#include <memory>
-#include <string>
-
-#include "ff.h"
-#include "freertos/portmacro.h"
-
-#include "audio_source.hpp"
-#include "codec.hpp"
-#include "future_fetcher.hpp"
-#include "tag_parser.hpp"
-#include "tasks.hpp"
-#include "types.hpp"
-
-namespace audio {
-
-/*
- * Audio source that fetches data from a FatFs (or exfat i guess) filesystem.
- *
- * All public methods are safe to call from any task.
- */
-class FatfsAudioInput : public IAudioSource {
- public:
-  explicit FatfsAudioInput(database::ITagParser&, tasks::WorkerPool&);
-  ~FatfsAudioInput();
-
-  /*
-   * Immediately cease reading any current source, and begin reading from the
-   * given file path.
-   */
-  auto SetPath(std::optional<std::string>) -> void;
-  auto SetPath(const std::string&,uint32_t offset = 0) -> void;
-  auto SetPath() -> void;
-
-  auto HasNewStream() -> bool override;
-  auto NextStream() -> std::shared_ptr<TaggedStream> override;
-
-  FatfsAudioInput(const FatfsAudioInput&) = delete;
-  FatfsAudioInput& operator=(const FatfsAudioInput&) = delete;
-
- private:
-  auto OpenFile(const std::string& path,uint32_t offset) -> bool;
-
-  auto ContainerToStreamType(database::Container)
-      -> std::optional<codecs::StreamType>;
-
-  database::ITagParser& tag_parser_;
-  tasks::WorkerPool& bg_worker_;
-
-  std::mutex new_stream_mutex_;
-  std::shared_ptr<TaggedStream> new_stream_;
-
-  std::atomic<bool> has_new_stream_;
-};
-
-}  // namespace audio
diff --git a/src/battery/CMakeLists.txt b/src/battery/CMakeLists.txt
deleted file mode 100644
index 313a3731..00000000
--- a/src/battery/CMakeLists.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-# Copyright 2023 jacqueline <me@jacqueline.id.au>
-#
-# SPDX-License-Identifier: GPL-3.0-only
-
-idf_component_register(
-  SRCS "battery.cpp"
-  INCLUDE_DIRS "include"
-  REQUIRES "drivers" "events")
-
-target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/codecs/CMakeLists.txt b/src/codecs/CMakeLists.txt
index b6481bd1..a1221adf 100644
--- a/src/codecs/CMakeLists.txt
+++ b/src/codecs/CMakeLists.txt
@@ -6,7 +6,7 @@ idf_component_register(
   SRCS "dr_flac.cpp" "codec.cpp" "mad.cpp" "opus.cpp" "vorbis.cpp"
        "source_buffer.cpp" "sample.cpp" "wav.cpp"
   INCLUDE_DIRS "include"
-  REQUIRES "result" "span" "libmad" "drflac" "tremor" "opusfile" "memory" "util"
+  REQUIRES "result" "libmad" "drflac" "tremor" "opusfile" "memory" "util"
        "komihash")
 
 target_compile_options("${COMPONENT_LIB}" PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/codecs/codec.cpp b/src/codecs/codec.cpp
index a51c40d6..c8e1a72c 100644
--- a/src/codecs/codec.cpp
+++ b/src/codecs/codec.cpp
@@ -9,8 +9,8 @@
 #include <memory>
 #include <optional>
 
-#include "mad.hpp"
 #include "dr_flac.hpp"
+#include "mad.hpp"
 #include "opus.hpp"
 #include "types.hpp"
 #include "vorbis.hpp"
diff --git a/src/codecs/dr_flac.cpp b/src/codecs/dr_flac.cpp
index 2f9acf8c..9341e938 100644
--- a/src/codecs/dr_flac.cpp
+++ b/src/codecs/dr_flac.cpp
@@ -100,7 +100,7 @@ auto DrFlacDecoder::OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
   return format;
 }
 
-auto DrFlacDecoder::DecodeTo(cpp::span<sample::Sample> output)
+auto DrFlacDecoder::DecodeTo(std::span<sample::Sample> output)
     -> cpp::result<OutputInfo, Error> {
   size_t frames_to_read = output.size() / flac_->channels / 2;
 
diff --git a/src/codecs/include/codec.hpp b/src/codecs/include/codec.hpp
index e48e3c58..4d588a98 100644
--- a/src/codecs/include/codec.hpp
+++ b/src/codecs/include/codec.hpp
@@ -6,19 +6,16 @@
 
 #pragma once
 
-#include <stdint.h>
-#include <sys/_stdint.h>
-
 #include <cstddef>
 #include <cstdint>
 #include <memory>
 #include <optional>
+#include <span>
 #include <string>
 #include <utility>
 
 #include "result.hpp"
 #include "sample.hpp"
-#include "span.hpp"
 #include "types.hpp"
 
 #include "memory_resource.hpp"
@@ -35,7 +32,7 @@ class IStream {
 
   auto type() -> StreamType { return t_; }
 
-  virtual auto Read(cpp::span<std::byte> dest) -> ssize_t = 0;
+  virtual auto Read(std::span<std::byte> dest) -> ssize_t = 0;
 
   virtual auto CanSeek() -> bool = 0;
 
@@ -54,7 +51,7 @@ class IStream {
   /*
    * Called by codecs to indicate that they've finished parsing any header data
    * within this stream, and are about to begin decoding.
-   * 
+   *
    * Currently used as a hint to the readahead stream to begin prefetching file
    * data.
    */
@@ -117,7 +114,7 @@ class ICodec {
    * Decodes metadata or headers from the given input stream, and returns the
    * format for the samples that will be decoded from it.
    */
-  virtual auto OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
+  virtual auto OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
       -> cpp::result<OutputFormat, Error> = 0;
 
   struct OutputInfo {
@@ -128,7 +125,7 @@ class ICodec {
   /*
    * Writes PCM samples to the given output buffer.
    */
-  virtual auto DecodeTo(cpp::span<sample::Sample> destination)
+  virtual auto DecodeTo(std::span<sample::Sample> destination)
       -> cpp::result<OutputInfo, Error> = 0;
 };
 
diff --git a/src/codecs/include/dr_flac.hpp b/src/codecs/include/dr_flac.hpp
index 547876f4..ac46e92f 100644
--- a/src/codecs/include/dr_flac.hpp
+++ b/src/codecs/include/dr_flac.hpp
@@ -10,13 +10,13 @@
 #include <cstdint>
 #include <memory>
 #include <optional>
+#include <span>
 #include <string>
 #include <utility>
 
 #include "dr_flac.h"
 #include "sample.hpp"
 #include "source_buffer.hpp"
-#include "span.hpp"
 
 #include "codec.hpp"
 
@@ -27,10 +27,10 @@ class DrFlacDecoder : public ICodec {
   DrFlacDecoder();
   ~DrFlacDecoder();
 
-  auto OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
+  auto OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
       -> cpp::result<OutputFormat, Error> override;
 
-  auto DecodeTo(cpp::span<sample::Sample> destination)
+  auto DecodeTo(std::span<sample::Sample> destination)
       -> cpp::result<OutputInfo, Error> override;
 
   DrFlacDecoder(const DrFlacDecoder&) = delete;
@@ -38,7 +38,7 @@ class DrFlacDecoder : public ICodec {
 
  private:
   std::shared_ptr<IStream> input_;
-  drflac *flac_;
+  drflac* flac_;
 };
 
 }  // namespace codecs
diff --git a/src/codecs/include/mad.hpp b/src/codecs/include/mad.hpp
index ead0b2a2..d1d0aac5 100644
--- a/src/codecs/include/mad.hpp
+++ b/src/codecs/include/mad.hpp
@@ -11,11 +11,11 @@
 #include <optional>
 #include <string>
 #include <utility>
+#include <span>
 
 #include "mad.h"
 #include "sample.hpp"
 #include "source_buffer.hpp"
-#include "span.hpp"
 
 #include "codec.hpp"
 
@@ -29,7 +29,7 @@ class MadMp3Decoder : public ICodec {
   auto OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
       -> cpp::result<OutputFormat, Error> override;
 
-  auto DecodeTo(cpp::span<sample::Sample> destination)
+  auto DecodeTo(std::span<sample::Sample> destination)
       -> cpp::result<OutputInfo, Error> override;
 
   MadMp3Decoder(const MadMp3Decoder&) = delete;
diff --git a/src/codecs/include/opus.hpp b/src/codecs/include/opus.hpp
index de2f7131..200b2d44 100644
--- a/src/codecs/include/opus.hpp
+++ b/src/codecs/include/opus.hpp
@@ -10,12 +10,12 @@
 #include <cstdint>
 #include <memory>
 #include <optional>
+#include <span>
 #include <string>
 #include <utility>
 
 #include "opusfile.h"
 #include "sample.hpp"
-#include "span.hpp"
 
 #include "codec.hpp"
 
@@ -26,10 +26,10 @@ class XiphOpusDecoder : public ICodec {
   XiphOpusDecoder();
   ~XiphOpusDecoder();
 
-  auto OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
+  auto OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
       -> cpp::result<OutputFormat, Error> override;
 
-  auto DecodeTo(cpp::span<sample::Sample> destination)
+  auto DecodeTo(std::span<sample::Sample> destination)
       -> cpp::result<OutputInfo, Error> override;
 
   XiphOpusDecoder(const XiphOpusDecoder&) = delete;
diff --git a/src/codecs/include/source_buffer.hpp b/src/codecs/include/source_buffer.hpp
index 7834834d..6444dd2c 100644
--- a/src/codecs/include/source_buffer.hpp
+++ b/src/codecs/include/source_buffer.hpp
@@ -9,8 +9,7 @@
 #include <cstddef>
 #include <cstdint>
 #include <functional>
-
-#include "span.hpp"
+#include <span>
 
 #include "codec.hpp"
 
@@ -22,15 +21,15 @@ class SourceBuffer {
   ~SourceBuffer();
 
   auto Refill(IStream* src) -> bool;
-  auto AddBytes(std::function<size_t(cpp::span<std::byte>)> writer) -> void;
-  auto ConsumeBytes(std::function<size_t(cpp::span<std::byte>)> reader) -> void;
+  auto AddBytes(std::function<size_t(std::span<std::byte>)> writer) -> void;
+  auto ConsumeBytes(std::function<size_t(std::span<std::byte>)> reader) -> void;
   auto Empty() -> void;
 
   SourceBuffer(const SourceBuffer&) = delete;
   SourceBuffer& operator=(const SourceBuffer&) = delete;
 
  private:
-  const cpp::span<std::byte> buffer_;
+  const std::span<std::byte> buffer_;
   size_t bytes_in_buffer_;
   size_t offset_of_bytes_;
 };
diff --git a/src/codecs/include/vorbis.hpp b/src/codecs/include/vorbis.hpp
index 3cf0f9ce..e6f393dc 100644
--- a/src/codecs/include/vorbis.hpp
+++ b/src/codecs/include/vorbis.hpp
@@ -10,12 +10,12 @@
 #include <cstdint>
 #include <memory>
 #include <optional>
+#include <span>
 #include <string>
 #include <utility>
 
 #include "ivorbisfile.h"
 #include "sample.hpp"
-#include "span.hpp"
 
 #include "codec.hpp"
 
@@ -26,10 +26,10 @@ class TremorVorbisDecoder : public ICodec {
   TremorVorbisDecoder();
   ~TremorVorbisDecoder();
 
-  auto OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
+  auto OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
       -> cpp::result<OutputFormat, Error> override;
 
-  auto DecodeTo(cpp::span<sample::Sample> destination)
+  auto DecodeTo(std::span<sample::Sample> destination)
       -> cpp::result<OutputInfo, Error> override;
 
   TremorVorbisDecoder(const TremorVorbisDecoder&) = delete;
diff --git a/src/codecs/include/wav.hpp b/src/codecs/include/wav.hpp
index 40138968..c09a3bb3 100644
--- a/src/codecs/include/wav.hpp
+++ b/src/codecs/include/wav.hpp
@@ -34,7 +34,7 @@ class WavDecoder : public ICodec {
   auto OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
       -> cpp::result<OutputFormat, Error> override;
 
-  auto DecodeTo(cpp::span<sample::Sample> destination)
+  auto DecodeTo(std::span<sample::Sample> destination)
       -> cpp::result<OutputInfo, Error> override;
 
   WavDecoder(const WavDecoder&) = delete;
diff --git a/src/codecs/mad.cpp b/src/codecs/mad.cpp
index e44e9922..01b2f721 100644
--- a/src/codecs/mad.cpp
+++ b/src/codecs/mad.cpp
@@ -74,7 +74,7 @@ auto MadMp3Decoder::OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
   while (!eof && !got_header) {
     eof = buffer_.Refill(input_.get());
 
-    buffer_.ConsumeBytes([&](cpp::span<std::byte> buf) -> size_t {
+    buffer_.ConsumeBytes([&](std::span<std::byte> buf) -> size_t {
       mad_stream_buffer(stream_.get(),
                         reinterpret_cast<const unsigned char*>(buf.data()),
                         buf.size_bytes());
@@ -130,7 +130,7 @@ auto MadMp3Decoder::OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
     }
     need_refill = false;
 
-    buffer_.ConsumeBytes([&](cpp::span<std::byte> buf) -> size_t {
+    buffer_.ConsumeBytes([&](std::span<std::byte> buf) -> size_t {
       mad_stream_buffer(stream_.get(),
                         reinterpret_cast<const unsigned char*>(buf.data()),
                         buf.size());
@@ -156,13 +156,13 @@ auto MadMp3Decoder::OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
   return output;
 }
 
-auto MadMp3Decoder::DecodeTo(cpp::span<sample::Sample> output)
+auto MadMp3Decoder::DecodeTo(std::span<sample::Sample> output)
     -> cpp::result<OutputInfo, Error> {
   if (current_sample_ < 0 && !is_eos_) {
     if (!is_eof_) {
       is_eof_ = buffer_.Refill(input_.get());
       if (is_eof_) {
-        buffer_.AddBytes([&](cpp::span<std::byte> buf) -> size_t {
+        buffer_.AddBytes([&](std::span<std::byte> buf) -> size_t {
           if (buf.size() < MAD_BUFFER_GUARD) {
             is_eof_ = false;
             return 0;
@@ -174,7 +174,7 @@ auto MadMp3Decoder::DecodeTo(cpp::span<sample::Sample> output)
       }
     }
 
-    buffer_.ConsumeBytes([&](cpp::span<std::byte> buf) -> size_t {
+    buffer_.ConsumeBytes([&](std::span<std::byte> buf) -> size_t {
       mad_stream_buffer(stream_.get(),
                         reinterpret_cast<const unsigned char*>(buf.data()),
                         buf.size());
diff --git a/src/codecs/opus.cpp b/src/codecs/opus.cpp
index a5220c4b..b5e7c3fc 100644
--- a/src/codecs/opus.cpp
+++ b/src/codecs/opus.cpp
@@ -140,7 +140,7 @@ auto XiphOpusDecoder::OpenStream(std::shared_ptr<IStream> input,
   };
 }
 
-auto XiphOpusDecoder::DecodeTo(cpp::span<sample::Sample> output)
+auto XiphOpusDecoder::DecodeTo(std::span<sample::Sample> output)
     -> cpp::result<OutputInfo, Error> {
   int samples_written = op_read_stereo(opus_, output.data(), output.size());
 
diff --git a/src/codecs/source_buffer.cpp b/src/codecs/source_buffer.cpp
index 0a986bc3..9cd648cd 100644
--- a/src/codecs/source_buffer.cpp
+++ b/src/codecs/source_buffer.cpp
@@ -39,7 +39,7 @@ auto SourceBuffer::Refill(IStream* src) -> bool {
     return false;
   }
   bool eof = false;
-  AddBytes([&](cpp::span<std::byte> buf) -> size_t {
+  AddBytes([&](std::span<std::byte> buf) -> size_t {
     ssize_t bytes_read = src->Read(buf);
     // Treat read errors as EOF.
     eof = bytes_read <= 0;
@@ -48,7 +48,7 @@ auto SourceBuffer::Refill(IStream* src) -> bool {
   return eof;
 }
 
-auto SourceBuffer::AddBytes(std::function<size_t(cpp::span<std::byte>)> writer)
+auto SourceBuffer::AddBytes(std::function<size_t(std::span<std::byte>)> writer)
     -> void {
   if (offset_of_bytes_ > 0) {
     std::memmove(buffer_.data(), buffer_.data() + offset_of_bytes_,
@@ -61,9 +61,9 @@ auto SourceBuffer::AddBytes(std::function<size_t(cpp::span<std::byte>)> writer)
 }
 
 auto SourceBuffer::ConsumeBytes(
-    std::function<size_t(cpp::span<std::byte>)> reader) -> void {
-  size_t bytes_consumed = std::invoke(
-      reader, buffer_.subspan(offset_of_bytes_, bytes_in_buffer_));
+    std::function<size_t(std::span<std::byte>)> reader) -> void {
+  size_t bytes_consumed =
+      std::invoke(reader, buffer_.subspan(offset_of_bytes_, bytes_in_buffer_));
   assert(bytes_consumed <= bytes_in_buffer_);
 
   bytes_in_buffer_ -= bytes_consumed;
diff --git a/src/codecs/test/test_mad.cpp b/src/codecs/test/test_mad.cpp
index e8c714e7..15c96eae 100644
--- a/src/codecs/test/test_mad.cpp
+++ b/src/codecs/test/test_mad.cpp
@@ -8,14 +8,14 @@
 
 #include <algorithm>
 #include <cstdint>
+#include <span>
 
 #include "catch2/catch.hpp"
-#include "span.hpp"
 
 #include "test.mp3.hpp"
 
-void load_mp3(cpp::span<std::byte> dest) {
-  cpp::span<std::byte> src(reinterpret_cast<std::byte*>(test_mp3),
+void load_mp3(std::span<std::byte> dest) {
+  std::span<std::byte> src(reinterpret_cast<std::byte*>(test_mp3),
                            test_mp3_len);
   std::copy(src.begin(), src.begin() + dest.size(), dest.begin());
 }
diff --git a/src/codecs/vorbis.cpp b/src/codecs/vorbis.cpp
index 9131451b..0b2af691 100644
--- a/src/codecs/vorbis.cpp
+++ b/src/codecs/vorbis.cpp
@@ -129,7 +129,7 @@ auto TremorVorbisDecoder::OpenStream(std::shared_ptr<IStream> input,
   };
 }
 
-auto TremorVorbisDecoder::DecodeTo(cpp::span<sample::Sample> output)
+auto TremorVorbisDecoder::DecodeTo(std::span<sample::Sample> output)
     -> cpp::result<OutputInfo, Error> {
   int unused = 0;
   long bytes_written =
diff --git a/src/codecs/wav.cpp b/src/codecs/wav.cpp
index 714ec237..f5b9d789 100644
--- a/src/codecs/wav.cpp
+++ b/src/codecs/wav.cpp
@@ -20,24 +20,24 @@ namespace codecs {
 
 [[maybe_unused]] static const char kTag[] = "wav";
 
-static inline auto bytes_to_u16(cpp::span<std::byte const, 2> bytes)
+static inline auto bytes_to_u16(std::span<std::byte const, 2> bytes)
     -> uint16_t {
   return (uint16_t)bytes[0] | (uint16_t)bytes[1] << 8;
 }
 
-static inline auto bytes_to_u32(cpp::span<std::byte const, 4> bytes)
+static inline auto bytes_to_u32(std::span<std::byte const, 4> bytes)
     -> uint32_t {
   return (uint32_t)bytes[0] | (uint32_t)bytes[1] << 8 |
          (uint32_t)bytes[2] << 16 | (uint32_t)bytes[3] << 24;
 }
 
-static inline auto bytes_to_str(cpp::span<std::byte const> bytes)
+static inline auto bytes_to_str(std::span<std::byte const> bytes)
     -> std::string {
   return std::string(reinterpret_cast<const char*>(bytes.data()),
-                    bytes.size_bytes());
+                     bytes.size_bytes());
 }
 
-static int16_t convert_f32_to_16_bit(cpp::span<const std::byte> bytes) {
+static int16_t convert_f32_to_16_bit(std::span<const std::byte> bytes) {
   uint64_t val = 0;
   val = (uint8_t)bytes[3];
   val = (val << 8) | (uint8_t)bytes[2];
@@ -57,7 +57,7 @@ static int16_t convert_f32_to_16_bit(cpp::span<const std::byte> bytes) {
   return sample::FromDouble(*fval);
 }
 
-static int16_t convert_f64_to_16_bit(cpp::span<const std::byte> bytes) {
+static int16_t convert_f64_to_16_bit(std::span<const std::byte> bytes) {
   uint64_t val = 0;
   val = (uint8_t)bytes[7];
   val = (val << 8) | (uint8_t)bytes[6];
@@ -71,7 +71,7 @@ static int16_t convert_f64_to_16_bit(cpp::span<const std::byte> bytes) {
   return sample::FromDouble(*fval);
 }
 
-static int16_t convert_to_16_bit(cpp::span<const std::byte> bytes) {
+static int16_t convert_to_16_bit(std::span<const std::byte> bytes) {
   int depth = bytes.size();
   int32_t val = 0;
   // If 8-bit Assume Unsigned
@@ -82,10 +82,13 @@ static int16_t convert_to_16_bit(cpp::span<const std::byte> bytes) {
   switch (depth) {
     case 4:
       val = (uint8_t)bytes[3];
+      [[fallthrough]];
     case 3:
       val = (val << 8) | (uint8_t)bytes[2];
+      [[fallthrough]];
     case 2:
       val = (val << 8) | (uint8_t)bytes[1];
+      [[fallthrough]];
     case 1:
       val = (val << 8) | (uint8_t)bytes[0];
   }
@@ -98,7 +101,7 @@ WavDecoder::WavDecoder() : input_(), buffer_() {}
 
 WavDecoder::~WavDecoder() {}
 
-auto WavDecoder::OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
+auto WavDecoder::OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
     -> cpp::result<OutputFormat, Error> {
   input_ = input;
 
@@ -123,7 +126,7 @@ auto WavDecoder::OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
   // - end of this part, next header we care about is 'data'
   // - and then the next 4 bytes = 32 bit int = size of data
 
-  auto buffer_span = cpp::span{buf};
+  auto buffer_span = std::span{buf};
 
   std::string riff = bytes_to_str(buffer_span.subspan(0, 4));
   if (riff != "RIFF") {
@@ -131,7 +134,7 @@ auto WavDecoder::OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
     return cpp::fail(Error::kMalformedData);
   }
 
-  uint32_t file_size = bytes_to_u32(buffer_span.subspan(4, 4)) + 8;
+  // uint32_t file_size = bytes_to_u32(buffer_span.subspan(4, 4)) + 8;
 
   std::string fmt_header = bytes_to_str(buffer_span.subspan(12, 4));
   ESP_LOGI(kTag, "fmt header found? %s",
@@ -142,9 +145,9 @@ auto WavDecoder::OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
   }
 
   // Size of the fmt header, should be 16, 18 or 40
-  uint32_t fmt_header_size = bytes_to_u32(buffer_span.subspan(16, 4));
+  // uint32_t fmt_header_size = bytes_to_u32(buffer_span.subspan(16, 4));
 
-  wave_format_ = bytes_to_u16(buffer_span.subspan(20, 2));
+  wave_format_ = bytes_to_u16(buffer_span.subspan<20, 2>());
   if (wave_format_ == kWaveFormatPCM) {
     ESP_LOGD(kTag, "wave format: PCM");
   } else if (wave_format_ == kWaveFormatExtensible) {
@@ -156,17 +159,17 @@ auto WavDecoder::OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
     return cpp::fail(Error::kUnsupportedFormat);
   }
 
-  num_channels_ = bytes_to_u16(buffer_span.subspan(22, 2));
+  num_channels_ = bytes_to_u16(buffer_span.subspan<22, 2>());
 
-  uint32_t samples_per_second = bytes_to_u32(buffer_span.subspan(24, 4));
+  uint32_t samples_per_second = bytes_to_u32(buffer_span.subspan<24, 4>());
 
-  uint32_t avg_bytes_per_second = bytes_to_u32(buffer_span.subspan(28, 4));
+  // uint32_t avg_bytes_per_second = bytes_to_u32(buffer_span.subspan(28, 4));
 
-  uint16_t block_align = bytes_to_u16(buffer_span.subspan(32, 2));
+  uint16_t block_align = bytes_to_u16(buffer_span.subspan<32, 2>());
 
   bytes_per_sample_ = block_align / num_channels_;
 
-  uint16_t bits_per_sample = bytes_to_u16(buffer_span.subspan(34, 2));
+  // uint16_t bits_per_sample = bytes_to_u16(buffer_span.subspan(34, 2));
 
   // find the start of the data chunk
   std::array<std::byte, 4> data_tag = {std::byte{0x64}, std::byte{0x61},
@@ -180,7 +183,7 @@ auto WavDecoder::OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
   int data_chunk_index = std::distance(buffer_span.begin(), data_loc.begin());
 
   uint32_t data_chunk_size =
-      bytes_to_u32(buffer_span.subspan(data_chunk_index + 4, 4));
+      bytes_to_u32(buffer_span.subspan(data_chunk_index + 4, 4).first<4>());
 
   // calculate number of samples
   int number_of_samples = data_chunk_size / bytes_per_sample_;
@@ -188,20 +191,20 @@ auto WavDecoder::OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
   // extension to the fmt chunk size (0 or 22)
   uint16_t extension_size = 0;
   if (wave_format_ == kWaveFormatExtensible) {
-    extension_size = bytes_to_u16(buffer_span.subspan(36, 2));
+    extension_size = bytes_to_u16(buffer_span.subspan<36, 2>());
   }
 
   // Parse extension if applicable
   if (extension_size == 22) {
     // Valid bits per sample
-    uint16_t valid_bits_per_sample = bytes_to_u16(buffer_span.subspan(38, 2));
+    // uint16_t valid_bits_per_sample = bytes_to_u16(buffer_span.subspan(38,
+    // 2));
 
-    uint32_t speaker_mask = bytes_to_u32(buffer_span.subspan(40, 4));
+    // uint32_t speaker_mask = bytes_to_u32(buffer_span.subspan(40, 4));
 
     // Parse subformat
-    subformat_ = bytes_to_u16(buffer_span.subspan(44, 2));
-    if (!(subformat_ == kWaveFormatPCM ||
-          subformat_ == kWaveFormatIEEEFloat)) {
+    subformat_ = bytes_to_u16(buffer_span.subspan<44, 2>());
+    if (!(subformat_ == kWaveFormatPCM || subformat_ == kWaveFormatIEEEFloat)) {
       ESP_LOGW(kTag, "WAVE extensible subformat_ not supported");
       return cpp::fail(Error::kUnsupportedFormat);
     }
@@ -210,7 +213,8 @@ auto WavDecoder::OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
   int64_t data_offset = offset * samples_per_second * bytes_per_sample_;
 
   // Seek track to start of data
-  input->SeekTo(data_chunk_index + 8 + data_offset, IStream::SeekFrom::kStartOfStream);
+  input->SeekTo(data_chunk_index + 8 + data_offset,
+                IStream::SeekFrom::kStartOfStream);
 
   output_format_ = {.num_channels = (uint8_t)num_channels_,
                     .sample_rate_hz = samples_per_second,
@@ -219,12 +223,12 @@ auto WavDecoder::OpenStream(std::shared_ptr<IStream> input,uint32_t offset)
   return output_format_;
 }
 
-auto WavDecoder::DecodeTo(cpp::span<sample::Sample> output)
+auto WavDecoder::DecodeTo(std::span<sample::Sample> output)
     -> cpp::result<OutputInfo, Error> {
   bool is_eof = buffer_.Refill(input_.get());
   size_t samples_written = 0;
 
-  buffer_.ConsumeBytes([&](cpp::span<std::byte> buf) -> size_t {
+  buffer_.ConsumeBytes([&](std::span<std::byte> buf) -> size_t {
     size_t bytes_read = buf.size_bytes();
     size_t frames_read =
         bytes_read / bytes_per_sample_ / output_format_.num_channels;
@@ -254,7 +258,6 @@ auto WavDecoder::DecodeTo(cpp::span<sample::Sample> output)
     return samples_written * bytes_per_sample_;
   });
 
-
   return OutputInfo{.samples_written = samples_written,
                     .is_stream_finished = samples_written == 0 && is_eof};
 }
diff --git a/src/database/CMakeLists.txt b/src/database/CMakeLists.txt
deleted file mode 100644
index 26c14815..00000000
--- a/src/database/CMakeLists.txt
+++ /dev/null
@@ -1,22 +0,0 @@
-# Copyright 2023 jacqueline <me@jacqueline.id.au>
-#
-# SPDX-License-Identifier: GPL-3.0-only
-
-idf_component_register(
-  SRCS "env_esp.cpp" "database.cpp" "track.cpp" "records.cpp"
-  "file_gatherer.cpp" "tag_parser.cpp" "index.cpp"
-  INCLUDE_DIRS "include"
-  REQUIRES "result" "span" "esp_psram" "fatfs" "libtags" "komihash" "cbor"
-  "tasks" "memory" "util" "tinyfsm" "events" "opusfile" "libcppbor")
-
-target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
-
-set(LEVELDB_BUILD_TESTS OFF)
-set(LEVELDB_BUILD_BENCHMARKS OFF)
-set(LEVELDB_INSTALL OFF)
-
-set(CMAKE_POLICY_DEFAULT_CMP0077 NEW)
-
-add_subdirectory($ENV{PROJ_PATH}/lib/leveldb ${CMAKE_CURRENT_BINARY_DIR}/leveldb)
-
-target_link_libraries(${COMPONENT_LIB} PUBLIC leveldb)
diff --git a/src/dev_console/CMakeLists.txt b/src/dev_console/CMakeLists.txt
deleted file mode 100644
index 5555bf61..00000000
--- a/src/dev_console/CMakeLists.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-# Copyright 2023 jacqueline <me@jacqueline.id.au>
-#
-# SPDX-License-Identifier: GPL-3.0-only
-
-idf_component_register(
-  SRCS "console.cpp"
-  INCLUDE_DIRS "include"
-  REQUIRES "console" "memory")
-target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/drivers/CMakeLists.txt b/src/drivers/CMakeLists.txt
index 891115d4..91534edb 100644
--- a/src/drivers/CMakeLists.txt
+++ b/src/drivers/CMakeLists.txt
@@ -7,6 +7,6 @@ idf_component_register(
   "i2c.cpp" "bluetooth.cpp" "spi.cpp" "display.cpp" "display_init.cpp"
   "samd.cpp" "wm8523.cpp" "nvs.cpp" "haptics.cpp" "spiffs.cpp"
   INCLUDE_DIRS "include"
-  REQUIRES "esp_adc" "fatfs" "result" "lvgl" "span" "tasks" "nvs_flash" "spiffs"
-  "bt" "tinyfsm" "util")
+  REQUIRES "esp_adc" "fatfs" "result" "lvgl" "nvs_flash" "spiffs" "bt"
+  "tasks" "tinyfsm" "util" "libcppbor")
 target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/drivers/adc.cpp b/src/drivers/adc.cpp
index 3379a1ae..3038f7f6 100644
--- a/src/drivers/adc.cpp
+++ b/src/drivers/adc.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "adc.hpp"
+#include "drivers/adc.hpp"
 #include <cstdint>
 
 #include "esp_adc/adc_cali.h"
diff --git a/src/drivers/bluetooth.cpp b/src/drivers/bluetooth.cpp
index 5d1b35fa..fcb764f6 100644
--- a/src/drivers/bluetooth.cpp
+++ b/src/drivers/bluetooth.cpp
@@ -1,4 +1,4 @@
-#include "bluetooth.hpp"
+#include "drivers/bluetooth.hpp"
 
 #include <stdint.h>
 
@@ -25,12 +25,11 @@
 #include "freertos/portmacro.h"
 #include "freertos/projdefs.h"
 #include "freertos/timers.h"
-#include "sample.hpp"
 #include "tinyfsm/include/tinyfsm.hpp"
 
-#include "bluetooth_types.hpp"
+#include "drivers/bluetooth_types.hpp"
+#include "drivers/nvs.hpp"
 #include "memory_resource.hpp"
-#include "nvs.hpp"
 #include "tasks.hpp"
 
 namespace drivers {
@@ -39,6 +38,7 @@ namespace drivers {
 
 DRAM_ATTR static StreamBufferHandle_t sStream = nullptr;
 DRAM_ATTR static std::atomic<float> sVolumeFactor = 1.f;
+DRAM_ATTR static std::atomic<uint32_t> sSamplesUsed = 0;
 
 static tasks::WorkerPool* sBgWorker;
 
@@ -74,6 +74,13 @@ IRAM_ATTR auto a2dp_data_cb(uint8_t* buf, int32_t buf_size) -> int32_t {
   }
   size_t bytes_received = xStreamBufferReceive(stream, buf, buf_size, 0);
 
+  size_t samples_received = bytes_received / 2;
+  if (UINT32_MAX - sSamplesUsed < samples_received) {
+    sSamplesUsed = samples_received - (UINT32_MAX - sSamplesUsed);
+  } else {
+    sSamplesUsed += samples_received;
+  }
+
   // Apply software volume scaling.
   int16_t* samples = reinterpret_cast<int16_t*>(buf);
   float factor = sVolumeFactor.load();
@@ -166,6 +173,10 @@ auto Bluetooth::SetVolumeFactor(float f) -> void {
   sVolumeFactor = f;
 }
 
+auto Bluetooth::SamplesUsed() -> uint32_t {
+  return sSamplesUsed;
+}
+
 auto Bluetooth::SetEventHandler(std::function<void(bluetooth::Event)> cb)
     -> void {
   auto lock = bluetooth::BluetoothState::lock();
diff --git a/src/drivers/display.cpp b/src/drivers/display.cpp
index 5c686811..b0a97b30 100644
--- a/src/drivers/display.cpp
+++ b/src/drivers/display.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "display.hpp"
+#include "drivers/display.hpp"
 #include <stdint.h>
 
 #include <cmath>
@@ -31,11 +31,11 @@
 #include "hal/spi_types.h"
 #include "lvgl/lvgl.h"
 
-#include "display_init.hpp"
-#include "gpios.hpp"
+#include "drivers/display_init.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/spi.hpp"
 #include "misc/lv_color.h"
 #include "soc/soc.h"
-#include "spi.hpp"
 #include "tasks.hpp"
 
 [[maybe_unused]] static const char* kTag = "DISPLAY";
diff --git a/src/drivers/display_init.cpp b/src/drivers/display_init.cpp
index a69826fa..edd36a8d 100644
--- a/src/drivers/display_init.cpp
+++ b/src/drivers/display_init.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "display_init.hpp"
+#include "drivers/display_init.hpp"
 
 namespace drivers {
 namespace displays {
diff --git a/src/drivers/gpios.cpp b/src/drivers/gpios.cpp
index aab932a7..64ba26a7 100644
--- a/src/drivers/gpios.cpp
+++ b/src/drivers/gpios.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "gpios.hpp"
+#include "drivers/gpios.hpp"
 
 #include <cstdint>
 
@@ -15,7 +15,7 @@
 #include "esp_intr_alloc.h"
 #include "hal/gpio_types.h"
 
-#include "i2c.hpp"
+#include "drivers/i2c.hpp"
 
 namespace drivers {
 
diff --git a/src/drivers/haptics.cpp b/src/drivers/haptics.cpp
index f7b18086..55fa9ad8 100644
--- a/src/drivers/haptics.cpp
+++ b/src/drivers/haptics.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "haptics.hpp"
+#include "drivers/haptics.hpp"
 #include <stdint.h>
 
 #include <cstdint>
@@ -21,7 +21,7 @@
 #include "hal/gpio_types.h"
 #include "hal/i2c_types.h"
 
-#include "i2c.hpp"
+#include "drivers/i2c.hpp"
 
 namespace drivers {
 
@@ -54,7 +54,8 @@ Haptics::Haptics(const std::variant<ErmMotor, LraMotor>& motor) {
     // Set library
     // TODO(robin): try the other libraries and test response. C is marginal, D
     // too much?
-    WriteRegister(Register::kWaveformLibrary, static_cast<uint8_t>(kDefaultErmLibrary));
+    WriteRegister(Register::kWaveformLibrary,
+                  static_cast<uint8_t>(kDefaultErmLibrary));
 
   } else if (std::holds_alternative<LraMotor>(motor)) {
     ESP_LOGI(kTag, "Setting up LRA motor...");
@@ -75,7 +76,8 @@ Haptics::Haptics(const std::variant<ErmMotor, LraMotor>& motor) {
                       ControlMask::kLraOpenLoop);
 
     // Set library; only option is the LRA one for, well, LRA motors.
-    WriteRegister(Register::kWaveformLibrary, static_cast<uint8_t>(Library::LRA));
+    WriteRegister(Register::kWaveformLibrary,
+                  static_cast<uint8_t>(Library::LRA));
   }
 
   // Set mode (internal trigger, on writing 1 to Go register)
@@ -123,7 +125,6 @@ auto Haptics::SetWaveformEffect(Effect effect) -> void {
   current_effect_ = effect;
 }
 
-
 auto Haptics::TourEffects() -> void {
   TourEffects(Effect::kFirst, Effect::kLast, kDefaultErmLibrary);
 }
@@ -174,7 +175,6 @@ auto Haptics::TourLibraries(Effect from, Effect to) -> void {
   }
 }
 
-
 auto Haptics::PowerDown() -> void {
   WriteRegister(Register::kMode, static_cast<uint8_t>(Mode::kInternalTrigger) |
                                      ModeMask::kStandby);
diff --git a/src/drivers/i2c.cpp b/src/drivers/i2c.cpp
index 7d25717a..793ce9f9 100644
--- a/src/drivers/i2c.cpp
+++ b/src/drivers/i2c.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "i2c.hpp"
+#include "drivers/i2c.hpp"
 
 #include <cstdint>
 
diff --git a/src/drivers/i2s_dac.cpp b/src/drivers/i2s_dac.cpp
index aef466c2..e5efe198 100644
--- a/src/drivers/i2s_dac.cpp
+++ b/src/drivers/i2s_dac.cpp
@@ -4,7 +4,8 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "i2s_dac.hpp"
+#include "drivers/i2s_dac.hpp"
+#include <stdint.h>
 
 #include <cmath>
 #include <cstdint>
@@ -25,11 +26,11 @@
 #include "hal/gpio_types.h"
 #include "hal/i2c_types.h"
 
-#include "gpios.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/i2c.hpp"
+#include "drivers/wm8523.hpp"
 #include "hal/i2s_types.h"
-#include "i2c.hpp"
 #include "soc/clk_tree_defs.h"
-#include "wm8523.hpp"
 
 namespace drivers {
 
@@ -140,7 +141,7 @@ auto I2SDac::SetPaused(bool paused) -> void {
   }
 }
 
-static volatile bool sSwapWords = false;
+DRAM_ATTR static volatile bool sSwapWords = false;
 
 auto I2SDac::Reconfigure(Channels ch, BitsPerSample bps, SampleRate rate)
     -> void {
@@ -207,7 +208,7 @@ auto I2SDac::Reconfigure(Channels ch, BitsPerSample bps, SampleRate rate)
   }
 }
 
-auto I2SDac::WriteData(const cpp::span<const std::byte>& data) -> void {
+auto I2SDac::WriteData(const std::span<const std::byte>& data) -> void {
   std::size_t bytes_written = 0;
   esp_err_t err = i2s_channel_write(i2s_handle_, data.data(), data.size_bytes(),
                                     &bytes_written, portMAX_DELAY);
@@ -216,6 +217,8 @@ auto I2SDac::WriteData(const cpp::span<const std::byte>& data) -> void {
   }
 }
 
+DRAM_ATTR static volatile uint32_t sSamplesRead = 0;
+
 extern "C" IRAM_ATTR auto callback(i2s_chan_handle_t handle,
                                    i2s_event_data_t* event,
                                    void* user_ctx) -> bool {
@@ -234,6 +237,14 @@ extern "C" IRAM_ATTR auto callback(i2s_chan_handle_t handle,
   size_t bytes_written =
       xStreamBufferReceiveFromISR(src, buf, event->size, &ret);
 
+  // Assume 16 bit samples.
+  size_t samples = bytes_written / 2;
+  if (UINT32_MAX - sSamplesRead < samples) {
+    sSamplesRead = samples - (UINT32_MAX - sSamplesRead);
+  } else {
+    sSamplesRead = sSamplesRead + samples;
+  }
+
   // The ESP32's I2S peripheral has a different endianness to its processors.
   // ESP-IDF handles this difference for stereo channels, but not for mono
   // channels. We therefore sometimes need to swap each pair of words as they're
@@ -275,6 +286,10 @@ auto I2SDac::SetSource(StreamBufferHandle_t buffer) -> void {
   }
 }
 
+auto I2SDac::SamplesUsed() -> uint32_t {
+  return sSamplesRead;
+}
+
 auto I2SDac::set_channel(bool enabled) -> void {
   if (i2s_active_ == enabled) {
     return;
diff --git a/src/drivers/include/a2dp_audio_output.hpp b/src/drivers/include/drivers/a2dp_audio_output.hpp
index 010470c6..010470c6 100644
--- a/src/drivers/include/a2dp_audio_output.hpp
+++ b/src/drivers/include/drivers/a2dp_audio_output.hpp
diff --git a/src/drivers/include/adc.hpp b/src/drivers/include/drivers/adc.hpp
index 3e94a9ee..3e94a9ee 100644
--- a/src/drivers/include/adc.hpp
+++ b/src/drivers/include/drivers/adc.hpp
diff --git a/src/drivers/include/bluetooth.hpp b/src/drivers/include/drivers/bluetooth.hpp
index 8da5ce2e..ad61fcc1 100644
--- a/src/drivers/include/bluetooth.hpp
+++ b/src/drivers/include/drivers/bluetooth.hpp
@@ -12,11 +12,11 @@
 #include <freertos/FreeRTOS.h>
 #include <freertos/stream_buffer.h>
 #include <stdint.h>
-#include "bluetooth_types.hpp"
+#include "drivers/bluetooth_types.hpp"
+#include "drivers/nvs.hpp"
 #include "esp_a2dp_api.h"
 #include "esp_avrc_api.h"
 #include "esp_gap_bt_api.h"
-#include "nvs.hpp"
 #include "tasks.hpp"
 #include "tinyfsm.hpp"
 #include "tinyfsm/include/tinyfsm.hpp"
@@ -44,6 +44,7 @@ class Bluetooth {
 
   auto SetSource(StreamBufferHandle_t) -> void;
   auto SetVolumeFactor(float) -> void;
+  auto SamplesUsed() -> uint32_t;
 
   auto SetEventHandler(std::function<void(bluetooth::Event)> cb) -> void;
 };
diff --git a/src/drivers/include/bluetooth_types.hpp b/src/drivers/include/drivers/bluetooth_types.hpp
index 7cfb236f..7cfb236f 100644
--- a/src/drivers/include/bluetooth_types.hpp
+++ b/src/drivers/include/drivers/bluetooth_types.hpp
diff --git a/src/drivers/include/display.hpp b/src/drivers/include/drivers/display.hpp
index d2e18a5c..6dc78e01 100644
--- a/src/drivers/include/display.hpp
+++ b/src/drivers/include/drivers/display.hpp
@@ -15,8 +15,8 @@
 #include "result.hpp"
 #include "tasks.hpp"
 
-#include "display_init.hpp"
-#include "gpios.hpp"
+#include "drivers/display_init.hpp"
+#include "drivers/gpios.hpp"
 
 namespace drivers {
 
diff --git a/src/drivers/include/display_init.hpp b/src/drivers/include/drivers/display_init.hpp
index 9bf5b3f5..9bf5b3f5 100644
--- a/src/drivers/include/display_init.hpp
+++ b/src/drivers/include/drivers/display_init.hpp
diff --git a/src/drivers/include/fatfs_audio_input.hpp b/src/drivers/include/drivers/fatfs_audio_input.hpp
index 705f6e7d..705f6e7d 100644
--- a/src/drivers/include/fatfs_audio_input.hpp
+++ b/src/drivers/include/drivers/fatfs_audio_input.hpp
diff --git a/src/drivers/include/gpios.hpp b/src/drivers/include/drivers/gpios.hpp
index e27a3ade..e27a3ade 100644
--- a/src/drivers/include/gpios.hpp
+++ b/src/drivers/include/drivers/gpios.hpp
diff --git a/src/drivers/include/haptics.hpp b/src/drivers/include/drivers/haptics.hpp
index 940c3c6d..940c3c6d 100644
--- a/src/drivers/include/haptics.hpp
+++ b/src/drivers/include/drivers/haptics.hpp
diff --git a/src/drivers/include/i2c.hpp b/src/drivers/include/drivers/i2c.hpp
index 0dc1e7c0..0dc1e7c0 100644
--- a/src/drivers/include/i2c.hpp
+++ b/src/drivers/include/drivers/i2c.hpp
diff --git a/src/drivers/include/i2s_dac.hpp b/src/drivers/include/drivers/i2s_dac.hpp
index bd837ca0..0776dbab 100644
--- a/src/drivers/include/i2s_dac.hpp
+++ b/src/drivers/include/drivers/i2s_dac.hpp
@@ -11,6 +11,7 @@
 #include <functional>
 #include <memory>
 #include <optional>
+#include <span>
 #include <utility>
 
 #include "driver/i2s_std.h"
@@ -20,9 +21,8 @@
 #include "freertos/portmacro.h"
 #include "freertos/stream_buffer.h"
 #include "result.hpp"
-#include "span.hpp"
 
-#include "gpios.hpp"
+#include "drivers/gpios.hpp"
 #include "sys/_stdint.h"
 
 namespace drivers {
@@ -68,9 +68,11 @@ class I2SDac {
 
   auto Reconfigure(Channels ch, BitsPerSample bps, SampleRate rate) -> void;
 
-  auto WriteData(const cpp::span<const std::byte>& data) -> void;
+  auto WriteData(const std::span<const std::byte>& data) -> void;
   auto SetSource(StreamBufferHandle_t buffer) -> void;
 
+  auto SamplesUsed() -> uint32_t;
+
   // Not copyable or movable.
   I2SDac(const I2SDac&) = delete;
   I2SDac& operator=(const I2SDac&) = delete;
diff --git a/src/drivers/include/nvs.hpp b/src/drivers/include/drivers/nvs.hpp
index 7c74ceb0..83bb8097 100644
--- a/src/drivers/include/nvs.hpp
+++ b/src/drivers/include/drivers/nvs.hpp
@@ -13,9 +13,8 @@
 #include "esp_err.h"
 #include "nvs.h"
 
-#include "bluetooth_types.hpp"
+#include "drivers/bluetooth_types.hpp"
 #include "lru_cache.hpp"
-#include "tasks.hpp"
 
 namespace drivers {
 
diff --git a/src/drivers/include/samd.hpp b/src/drivers/include/drivers/samd.hpp
index 55ea513c..55ea513c 100644
--- a/src/drivers/include/samd.hpp
+++ b/src/drivers/include/drivers/samd.hpp
diff --git a/src/drivers/include/spi.hpp b/src/drivers/include/drivers/spi.hpp
index 60638f71..60638f71 100644
--- a/src/drivers/include/spi.hpp
+++ b/src/drivers/include/drivers/spi.hpp
diff --git a/src/drivers/include/spiffs.hpp b/src/drivers/include/drivers/spiffs.hpp
index 04478590..04478590 100644
--- a/src/drivers/include/spiffs.hpp
+++ b/src/drivers/include/drivers/spiffs.hpp
diff --git a/src/drivers/include/storage.hpp b/src/drivers/include/drivers/storage.hpp
index 836bbbdc..3aefff2d 100644
--- a/src/drivers/include/storage.hpp
+++ b/src/drivers/include/drivers/storage.hpp
@@ -15,7 +15,7 @@
 #include "ff.h"
 #include "result.hpp"
 
-#include "gpios.hpp"
+#include "drivers/gpios.hpp"
 
 namespace drivers {
 
diff --git a/src/drivers/include/touchwheel.hpp b/src/drivers/include/drivers/touchwheel.hpp
index 18ace2b4..60902087 100644
--- a/src/drivers/include/touchwheel.hpp
+++ b/src/drivers/include/drivers/touchwheel.hpp
@@ -12,7 +12,7 @@
 #include "esp_err.h"
 #include "result.hpp"
 
-#include "gpios.hpp"
+#include "drivers/gpios.hpp"
 
 namespace drivers {
 
diff --git a/src/drivers/include/wm8523.hpp b/src/drivers/include/drivers/wm8523.hpp
index a64f6bac..a64f6bac 100644
--- a/src/drivers/include/wm8523.hpp
+++ b/src/drivers/include/drivers/wm8523.hpp
diff --git a/src/drivers/nvs.cpp b/src/drivers/nvs.cpp
index c8befe48..1389fd0d 100644
--- a/src/drivers/nvs.cpp
+++ b/src/drivers/nvs.cpp
@@ -4,22 +4,19 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "nvs.hpp"
-#include <stdint.h>
-#include <sys/_stdint.h>
+#include "drivers/nvs.hpp"
 
 #include <cstdint>
 #include <memory>
 
-#include "bluetooth.hpp"
-#include "bluetooth_types.hpp"
 #include "cppbor.h"
 #include "cppbor_parse.h"
+#include "drivers/bluetooth.hpp"
+#include "drivers/bluetooth_types.hpp"
+#include "drivers/wm8523.hpp"
 #include "esp_log.h"
 #include "nvs.h"
 #include "nvs_flash.h"
-#include "tasks.hpp"
-#include "wm8523.hpp"
 
 namespace drivers {
 
@@ -42,8 +39,8 @@ static constexpr char kKeyDisplayRows[] = "disprows";
 static constexpr char kKeyHapticMotorType[] = "hapticmtype";
 static constexpr char kKeyDbAutoIndex[] = "dbautoindex";
 
-static auto nvs_get_string(nvs_handle_t nvs, const char* key)
-    -> std::optional<std::string> {
+static auto nvs_get_string(nvs_handle_t nvs,
+                           const char* key) -> std::optional<std::string> {
   size_t len = 0;
   if (nvs_get_blob(nvs, key, NULL, &len) != ESP_OK) {
     return {};
@@ -190,8 +187,7 @@ auto NvsStorage::Read() -> void {
   lock_polarity_.read(handle_);
   display_cols_.read(handle_);
   display_rows_.read(handle_);
-  haptic_motor_type_.read(handle_),
-  brightness_.read(handle_);
+  haptic_motor_type_.read(handle_), brightness_.read(handle_);
   sensitivity_.read(handle_);
   amp_max_vol_.read(handle_);
   amp_cur_vol_.read(handle_);
@@ -208,8 +204,7 @@ auto NvsStorage::Write() -> bool {
   lock_polarity_.write(handle_);
   display_cols_.write(handle_);
   display_rows_.write(handle_);
-  haptic_motor_type_.write(handle_),
-  brightness_.write(handle_);
+  haptic_motor_type_.write(handle_), brightness_.write(handle_);
   sensitivity_.write(handle_);
   amp_max_vol_.write(handle_);
   amp_cur_vol_.write(handle_);
@@ -290,8 +285,8 @@ auto NvsStorage::BluetoothVolume(const bluetooth::mac_addr_t& mac) -> uint8_t {
   return bt_volumes_.Get(mac).value_or(50);
 }
 
-auto NvsStorage::BluetoothVolume(const bluetooth::mac_addr_t& mac, uint8_t vol)
-    -> void {
+auto NvsStorage::BluetoothVolume(const bluetooth::mac_addr_t& mac,
+                                 uint8_t vol) -> void {
   std::lock_guard<std::mutex> lock{mutex_};
   bt_volumes_dirty_ = true;
   bt_volumes_.Put(mac, vol);
diff --git a/src/drivers/samd.cpp b/src/drivers/samd.cpp
index e47d9cfe..c5e8c08a 100644
--- a/src/drivers/samd.cpp
+++ b/src/drivers/samd.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "samd.hpp"
+#include "drivers/samd.hpp"
 
 #include <cstdint>
 #include <optional>
@@ -15,7 +15,7 @@
 #include "hal/gpio_types.h"
 #include "hal/i2c_types.h"
 
-#include "i2c.hpp"
+#include "drivers/i2c.hpp"
 
 enum Registers : uint8_t {
   kSamdFirmwareVersion = 0,
diff --git a/src/drivers/spi.cpp b/src/drivers/spi.cpp
index ae6f83a2..f4d3ea6e 100644
--- a/src/drivers/spi.cpp
+++ b/src/drivers/spi.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "spi.hpp"
+#include "drivers/spi.hpp"
 
 #include "driver/sdspi_host.h"
 #include "driver/spi_common.h"
diff --git a/src/drivers/spiffs.cpp b/src/drivers/spiffs.cpp
index f03d2f68..30a2db33 100644
--- a/src/drivers/spiffs.cpp
+++ b/src/drivers/spiffs.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "spiffs.hpp"
+#include "drivers/spiffs.hpp"
 
 #include "esp_err.h"
 #include "esp_log.h"
diff --git a/src/drivers/storage.cpp b/src/drivers/storage.cpp
index b3588130..b2b7174e 100644
--- a/src/drivers/storage.cpp
+++ b/src/drivers/storage.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "storage.hpp"
+#include "drivers/storage.hpp"
 
 #include <atomic>
 #include <memory>
@@ -23,7 +23,7 @@
 #include "hal/spi_types.h"
 #include "sdmmc_cmd.h"
 
-#include "gpios.hpp"
+#include "drivers/gpios.hpp"
 #include "memory_resource.hpp"
 
 [[maybe_unused]] static const char* kTag = "SDSTORAGE";
diff --git a/src/drivers/test/test_dac.cpp b/src/drivers/test/test_dac.cpp
index e8d8dd94..2269f280 100644
--- a/src/drivers/test/test_dac.cpp
+++ b/src/drivers/test/test_dac.cpp
@@ -10,8 +10,8 @@
 
 #include "catch2/catch.hpp"
 
-#include "gpios.hpp"
-#include "i2c.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/i2c.hpp"
 #include "i2c_fixture.hpp"
 
 namespace drivers {
diff --git a/src/drivers/test/test_gpio_expander.cpp b/src/drivers/test/test_gpio_expander.cpp
index 972bcf09..7c323313 100644
--- a/src/drivers/test/test_gpio_expander.cpp
+++ b/src/drivers/test/test_gpio_expander.cpp
@@ -4,11 +4,11 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "gpios.hpp"
+#include "drivers/gpios.hpp"
 
 #include "catch2/catch.hpp"
 
-#include "i2c.hpp"
+#include "drivers/i2c.hpp"
 #include "i2c_fixture.hpp"
 
 namespace drivers {
diff --git a/src/drivers/test/test_storage.cpp b/src/drivers/test/test_storage.cpp
index 062de3af..f97a0a85 100644
--- a/src/drivers/test/test_storage.cpp
+++ b/src/drivers/test/test_storage.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "storage.hpp"
+#include "drivers/storage.hpp"
 
 #include <dirent.h>
 
@@ -14,10 +14,10 @@
 
 #include "catch2/catch.hpp"
 
-#include "gpios.hpp"
-#include "i2c.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/i2c.hpp"
+#include "drivers/spi.hpp"
 #include "i2c_fixture.hpp"
-#include "spi.hpp"
 #include "spi_fixture.hpp"
 
 namespace drivers {
diff --git a/src/drivers/touchwheel.cpp b/src/drivers/touchwheel.cpp
index 41b9a6af..5d55c6f2 100644
--- a/src/drivers/touchwheel.cpp
+++ b/src/drivers/touchwheel.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "touchwheel.hpp"
+#include "drivers/touchwheel.hpp"
 #include <stdint.h>
 
 #include <cstdint>
@@ -18,7 +18,7 @@
 #include "hal/gpio_types.h"
 #include "hal/i2c_types.h"
 
-#include "i2c.hpp"
+#include "drivers/i2c.hpp"
 
 namespace drivers {
 
diff --git a/src/drivers/wm8523.cpp b/src/drivers/wm8523.cpp
index 9fe3e001..26316387 100644
--- a/src/drivers/wm8523.cpp
+++ b/src/drivers/wm8523.cpp
@@ -3,14 +3,14 @@
  *
  * SPDX-License-Identifier: GPL-3.0-only
  */
-#include "wm8523.hpp"
+#include "drivers/wm8523.hpp"
 
 #include <cstdint>
 
 #include "esp_err.h"
 
+#include "drivers/i2c.hpp"
 #include "hal/i2c_types.h"
-#include "i2c.hpp"
 
 namespace drivers {
 namespace wm8523 {
diff --git a/src/events/CMakeLists.txt b/src/events/CMakeLists.txt
deleted file mode 100644
index 132c39c7..00000000
--- a/src/events/CMakeLists.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-# Copyright 2023 jacqueline <me@jacqueline.id.au>
-#
-# SPDX-License-Identifier: GPL-3.0-only
-
-idf_component_register(
-  SRCS "event_queue.cpp"
-  INCLUDE_DIRS "include"
-  REQUIRES "tinyfsm" "ui")
-target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/graphics/CMakeLists.txt b/src/graphics/CMakeLists.txt
new file mode 100644
index 00000000..5b2c5d58
--- /dev/null
+++ b/src/graphics/CMakeLists.txt
@@ -0,0 +1,7 @@
+# Copyright 2024 jacqueline <me@jacqueline.id.au>
+#
+# SPDX-License-Identifier: GPL-3.0-only
+
+idf_component_register(
+  SRCS "font_fusion_10.c" "font_fusion_12.c" "splash.c"
+  REQUIRES "lvgl")
diff --git a/src/ui/font_fusion_10.c b/src/graphics/font_fusion_10.c
index 67143440..67143440 100644
--- a/src/ui/font_fusion_10.c
+++ b/src/graphics/font_fusion_10.c
diff --git a/src/ui/font_fusion_12.c b/src/graphics/font_fusion_12.c
index 97c311b8..97c311b8 100644
--- a/src/ui/font_fusion_12.c
+++ b/src/graphics/font_fusion_12.c
diff --git a/src/ui/splash.c b/src/graphics/splash.c
index 61eff739..61eff739 100644
--- a/src/ui/splash.c
+++ b/src/graphics/splash.c
diff --git a/src/input/CMakeLists.txt b/src/input/CMakeLists.txt
deleted file mode 100644
index 4754ba47..00000000
--- a/src/input/CMakeLists.txt
+++ /dev/null
@@ -1,13 +0,0 @@
-# Copyright 2023 jacqueline <me@jacqueline.id.au>
-#
-# SPDX-License-Identifier: GPL-3.0-only
-
-idf_component_register(
-  SRCS "input_touch_wheel.cpp" "input_touch_dpad.cpp" "input_trigger.cpp"
-  "input_volume_buttons.cpp" "lvgl_input_driver.cpp" "feedback_haptics.cpp"
-  "device_factory.cpp" "input_nav_buttons.cpp" "input_hook.cpp"
-  "input_hook_actions.cpp"
-  INCLUDE_DIRS "include"
-  REQUIRES "drivers" "lvgl" "events" "system_fsm")
-
-target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/input/include/lvgl_input_driver.hpp b/src/input/include/lvgl_input_driver.hpp
deleted file mode 100644
index 9f43d27f..00000000
--- a/src/input/include/lvgl_input_driver.hpp
+++ /dev/null
@@ -1,60 +0,0 @@
-/*
- * Copyright 2023 jacqueline <me@jacqueline.id.au>
- *
- * SPDX-License-Identifier: GPL-3.0-only
- */
-
-#pragma once
-
-#include <cstdint>
-#include <deque>
-#include <memory>
-#include <set>
-
-#include "core/lv_group.h"
-#include "device_factory.hpp"
-#include "feedback_device.hpp"
-#include "gpios.hpp"
-#include "hal/lv_hal_indev.h"
-
-#include "input_device.hpp"
-#include "nvs.hpp"
-#include "property.hpp"
-#include "touchwheel.hpp"
-
-namespace input {
-
-/*
- * Implementation of an LVGL input device. This class composes multiple
- * IInputDevice and IFeedbackDevice instances together into a single LVGL
- * device.
- */
-class LvglInputDriver {
- public:
-  LvglInputDriver(drivers::NvsStorage& nvs, DeviceFactory&);
-
-  auto mode() -> lua::Property& { return mode_; }
-
-  auto read(lv_indev_data_t* data) -> void;
-  auto feedback(uint8_t) -> void;
-
-  auto registration() -> lv_indev_t* { return registration_; }
-  auto lock(bool l) -> void { is_locked_ = l; }
-
-  auto pushHooks(lua_State* L) -> int;
-
- private:
-  drivers::NvsStorage& nvs_;
-  DeviceFactory& factory_;
-
-  lua::Property mode_;
-  lv_indev_drv_t driver_;
-  lv_indev_t* registration_;
-
-  std::vector<std::shared_ptr<IInputDevice>> inputs_;
-  std::vector<std::shared_ptr<IFeedbackDevice>> feedbacks_;
-
-  bool is_locked_;
-};
-
-}  // namespace input
diff --git a/src/input/lvgl_input_driver.cpp b/src/input/lvgl_input_driver.cpp
deleted file mode 100644
index 61a85fa5..00000000
--- a/src/input/lvgl_input_driver.cpp
+++ /dev/null
@@ -1,127 +0,0 @@
-/*
- * Copyright 2023 jacqueline <me@jacqueline.id.au>
- *
- * SPDX-License-Identifier: GPL-3.0-only
- */
-
-#include "lvgl_input_driver.hpp"
-#include <stdint.h>
-
-#include <cstdint>
-#include <memory>
-#include <variant>
-
-#include "device_factory.hpp"
-#include "feedback_haptics.hpp"
-#include "input_touch_wheel.hpp"
-#include "input_trigger.hpp"
-#include "input_volume_buttons.hpp"
-#include "lauxlib.h"
-#include "lua.h"
-#include "lvgl.h"
-#include "nvs.hpp"
-#include "property.hpp"
-
-[[maybe_unused]] static constexpr char kTag[] = "input";
-
-namespace input {
-
-static void read_cb(lv_indev_drv_t* drv, lv_indev_data_t* data) {
-  LvglInputDriver* instance =
-      reinterpret_cast<LvglInputDriver*>(drv->user_data);
-  instance->read(data);
-}
-
-static void feedback_cb(lv_indev_drv_t* drv, uint8_t event) {
-  LvglInputDriver* instance =
-      reinterpret_cast<LvglInputDriver*>(drv->user_data);
-  instance->feedback(event);
-}
-
-auto intToMode(int raw) -> std::optional<drivers::NvsStorage::InputModes> {
-  switch (raw) {
-    case 0:
-      return drivers::NvsStorage::InputModes::kButtonsOnly;
-    case 1:
-      return drivers::NvsStorage::InputModes::kButtonsWithWheel;
-    case 2:
-      return drivers::NvsStorage::InputModes::kDirectionalWheel;
-    case 3:
-      return drivers::NvsStorage::InputModes::kRotatingWheel;
-    default:
-      return {};
-  }
-}
-
-LvglInputDriver::LvglInputDriver(drivers::NvsStorage& nvs,
-                                 DeviceFactory& factory)
-    : nvs_(nvs),
-      factory_(factory),
-      mode_(static_cast<int>(nvs.PrimaryInput()),
-            [&](const lua::LuaValue& val) {
-              if (!std::holds_alternative<int>(val)) {
-                return false;
-              }
-              auto mode = intToMode(std::get<int>(val));
-              if (!mode) {
-                return false;
-              }
-              nvs.PrimaryInput(*mode);
-              inputs_ = factory.createInputs(*mode);
-              return true;
-            }),
-      driver_(),
-      registration_(nullptr),
-      inputs_(factory.createInputs(nvs.PrimaryInput())),
-      feedbacks_(factory.createFeedbacks()),
-      is_locked_(false) {
-  lv_indev_drv_init(&driver_);
-  driver_.type = LV_INDEV_TYPE_ENCODER;
-  driver_.read_cb = read_cb;
-  driver_.feedback_cb = feedback_cb;
-  driver_.user_data = this;
-  driver_.long_press_time = kLongPressDelayMs;
-  driver_.long_press_repeat_time = kRepeatDelayMs;
-
-  registration_ = lv_indev_drv_register(&driver_);
-}
-
-auto LvglInputDriver::read(lv_indev_data_t* data) -> void {
-  // TODO: we should pass lock state on to the individual devices, since they
-  // may wish to either ignore the lock state, or power down until unlock.
-  if (is_locked_) {
-    return;
-  }
-  for (auto&& device : inputs_) {
-    device->read(data);
-  }
-}
-
-auto LvglInputDriver::feedback(uint8_t event) -> void {
-  if (is_locked_) {
-    return;
-  }
-  for (auto&& device : feedbacks_) {
-    device->feedback(event);
-  }
-}
-
-auto LvglInputDriver::pushHooks(lua_State* L) -> int {
-  lua_newtable(L);
-
-  for (auto& dev : inputs_) {
-    lua_pushlstring(L, dev->name().data(), dev->name().size());
-    lua_newtable(L);
-
-    for (auto& hook : dev->hooks()) {
-      lua_pushlstring(L, hook.name().data(), hook.name().size());
-      hook.pushHooks(L);
-      lua_rawset(L, -3);
-    }
-
-    lua_rawset(L, -3);
-  }
-  return 1;
-}
-
-}  // namespace input
diff --git a/src/locale/CMakeLists.txt b/src/locale/CMakeLists.txt
index 627ca314..9c1c2619 100644
--- a/src/locale/CMakeLists.txt
+++ b/src/locale/CMakeLists.txt
@@ -6,6 +6,6 @@ idf_component_register(
   SRCS "collation.cpp" "strxfrm_l.c"
   INCLUDE_DIRS "include"
   PRIV_INCLUDE_DIRS "priv_include"
-  REQUIRES "span" "esp_partition" "spi_flash")
+  REQUIRES "esp_partition" "spi_flash")
 
 target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/locale/include/collation.hpp b/src/locale/include/collation.hpp
index b666860d..88f499c4 100644
--- a/src/locale/include/collation.hpp
+++ b/src/locale/include/collation.hpp
@@ -9,10 +9,10 @@
 #include <cstddef>
 #include <memory>
 #include <optional>
+#include <span>
 #include <string>
 
 #include "esp_partition.h"
-#include "span.hpp"
 
 #include "strxfrm.h"
 
diff --git a/src/lua/CMakeLists.txt b/src/lua/CMakeLists.txt
deleted file mode 100644
index 4aa5a123..00000000
--- a/src/lua/CMakeLists.txt
+++ /dev/null
@@ -1,13 +0,0 @@
-# Copyright 2023 jacqueline <me@jacqueline.id.au>
-#
-# SPDX-License-Identifier: GPL-3.0-only
-
-idf_component_register(
-  SRCS "lua_theme.cpp" "lua_thread.cpp" "bridge.cpp" "property.cpp" "lua_database.cpp"
-  "lua_queue.cpp" "lua_version.cpp" "lua_theme.cpp" "lua_controls.cpp" "registry.cpp"
-  "lua_screen.cpp" "lua_filesystem.cpp" "file_iterator.cpp"
-  INCLUDE_DIRS "include"
-  REQUIRES "drivers" "lvgl" "tinyfsm" "events" "system_fsm" "database" "fatfs"
-  "esp_timer" "battery" "esp-idf-lua" "luavgl" "lua-linenoise" "lua-term"
-  "esp_app_format")
-target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/main/CMakeLists.txt b/src/main/CMakeLists.txt
index 3ae92ac2..9019c254 100644
--- a/src/main/CMakeLists.txt
+++ b/src/main/CMakeLists.txt
@@ -2,8 +2,5 @@
 #
 # SPDX-License-Identifier: GPL-3.0-only
 
-idf_component_register(
-  SRCS "main.cpp"
-  INCLUDE_DIRS "."
-  REQUIRES "audio" "ui" "system_fsm" "events")
+idf_component_register(SRCS "main.cpp" INCLUDE_DIRS "." REQUIRES "tangara")
 target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/main/main.cpp b/src/main/main.cpp
index cf27b132..8c7565f3 100644
--- a/src/main/main.cpp
+++ b/src/main/main.cpp
@@ -7,14 +7,14 @@
 #include "freertos/FreeRTOS.h"
 #include "freertos/portmacro.h"
 
-#include "i2c.hpp"
-#include "system_events.hpp"
 #include "tinyfsm.hpp"
 
-#include "audio_fsm.hpp"
-#include "event_queue.hpp"
-#include "system_fsm.hpp"
-#include "ui_fsm.hpp"
+#include "audio/audio_fsm.hpp"
+#include "drivers/i2c.hpp"
+#include "events/event_queue.hpp"
+#include "system_fsm/system_events.hpp"
+#include "system_fsm/system_fsm.hpp"
+#include "ui/ui_fsm.hpp"
 
 extern "C" void app_main(void) {
   ESP_ERROR_CHECK(drivers::init_i2c());
diff --git a/src/memory/include/himem.hpp b/src/memory/include/himem.hpp
index 81166e0d..f70648a9 100644
--- a/src/memory/include/himem.hpp
+++ b/src/memory/include/himem.hpp
@@ -8,9 +8,9 @@
 
 #include <cstddef>
 #include <cstdint>
+#include <span>
 
 #include "esp32/himem.h"
-#include "span.hpp"
 
 /*
  * Wrapper around an ESP-IDF himem allocation, which uses RAII to clean up after
@@ -62,14 +62,14 @@ class MappableRegion {
     }
   }
 
-  auto Get() -> cpp::span<std::byte> {
+  auto Get() -> std::span<std::byte> {
     if (bytes_ == nullptr) {
       return {};
     }
     return {bytes_, size};
   }
 
-  auto Map(const HimemAlloc<size>& alloc) -> cpp::span<std::byte> {
+  auto Map(const HimemAlloc<size>& alloc) -> std::span<std::byte> {
     assert(bytes_ == nullptr);
     ESP_ERROR_CHECK(esp_himem_map(alloc.handle, range_handle, 0, 0, size, 0,
                                   reinterpret_cast<void**>(&bytes_)));
diff --git a/src/system_fsm/CMakeLists.txt b/src/system_fsm/CMakeLists.txt
deleted file mode 100644
index e98d4653..00000000
--- a/src/system_fsm/CMakeLists.txt
+++ /dev/null
@@ -1,11 +0,0 @@
-# Copyright 2023 jacqueline <me@jacqueline.id.au>
-#
-# SPDX-License-Identifier: GPL-3.0-only
-
-idf_component_register(
-  SRCS "system_fsm.cpp" "running.cpp" "booting.cpp" "idle.cpp"
-  "service_locator.cpp"
-  INCLUDE_DIRS "include"
-  REQUIRES "tinyfsm" "drivers" "database" "ui" "result" "events" "audio"
-  "app_console" "battery" "locale")
-target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/tangara/CMakeLists.txt b/src/tangara/CMakeLists.txt
new file mode 100644
index 00000000..fb8d1041
--- /dev/null
+++ b/src/tangara/CMakeLists.txt
@@ -0,0 +1,22 @@
+# Copyright 2024 jacqueline <me@jacqueline.id.au>
+#
+# SPDX-License-Identifier: GPL-3.0-only
+
+idf_component_register(
+  SRC_DIRS "app_console" "audio" "battery" "database" "dev_console" "events"
+  "input" "lua" "system_fsm" "ui"
+  INCLUDE_DIRS "."
+  REQUIRES "codecs" "drivers" "locale" "memory" "tasks" "util" "graphics"
+  "tinyfsm" "lvgl" "esp_timer" "luavgl" "esp_app_format" "libcppbor" "libtags"
+  "komihash" "result" "esp_psram" "fatfs" "millershuffle" "speexdsp" "console"
+  "esp-idf-lua" "lua-linenoise" "lua-term")
+target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
+
+set(LEVELDB_BUILD_TESTS OFF)
+set(LEVELDB_BUILD_BENCHMARKS OFF)
+set(LEVELDB_INSTALL OFF)
+
+set(CMAKE_POLICY_DEFAULT_CMP0077 NEW)
+
+add_subdirectory($ENV{PROJ_PATH}/lib/leveldb ${CMAKE_CURRENT_BINARY_DIR}/leveldb)
+target_link_libraries(${COMPONENT_LIB} PUBLIC leveldb)
diff --git a/src/app_console/app_console.cpp b/src/tangara/app_console/app_console.cpp
index 7c7c1abc..e3048ba2 100644
--- a/src/app_console/app_console.cpp
+++ b/src/tangara/app_console/app_console.cpp
@@ -4,11 +4,9 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "app_console.hpp"
+#include "app_console/app_console.hpp"
 
 #include <dirent.h>
-#include <stdint.h>
-#include <sys/_stdint.h>
 
 #include <algorithm>
 #include <cstdint>
@@ -21,11 +19,7 @@
 #include <string>
 
 #include "FreeRTOSConfig.h"
-#include "audio_events.hpp"
-#include "audio_fsm.hpp"
-#include "bluetooth.hpp"
-#include "bluetooth_types.hpp"
-#include "database.hpp"
+
 #include "esp_app_desc.h"
 #include "esp_console.h"
 #include "esp_err.h"
@@ -34,19 +28,25 @@
 #include "esp_intr_alloc.h"
 #include "esp_log.h"
 #include "esp_system.h"
-#include "event_queue.hpp"
 #include "ff.h"
-#include "freertos/FreeRTOSConfig_arch.h"
 #include "freertos/projdefs.h"
-#include "haptics.hpp"
-#include "index.hpp"
-#include "lua_registry.hpp"
+
+#include "drivers/bluetooth.hpp"
+#include "drivers/bluetooth_types.hpp"
+#include "drivers/haptics.hpp"
+#include "drivers/samd.hpp"
 #include "memory_resource.hpp"
-#include "samd.hpp"
-#include "service_locator.hpp"
-#include "system_events.hpp"
-#include "track.hpp"
-#include "ui_events.hpp"
+
+#include "audio/audio_events.hpp"
+#include "audio/audio_fsm.hpp"
+#include "database/database.hpp"
+#include "database/index.hpp"
+#include "database/track.hpp"
+#include "events/event_queue.hpp"
+#include "lua/lua_registry.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "system_fsm/system_events.hpp"
+#include "ui/ui_events.hpp"
 
 namespace console {
 
diff --git a/src/app_console/include/app_console.hpp b/src/tangara/app_console/app_console.hpp
index 5981cc04..b88b1330 100644
--- a/src/app_console/include/app_console.hpp
+++ b/src/tangara/app_console/app_console.hpp
@@ -8,12 +8,12 @@
 
 #include <memory>
 
-#include "bluetooth.hpp"
-#include "console.hpp"
-#include "database.hpp"
-#include "samd.hpp"
-#include "service_locator.hpp"
-#include "track_queue.hpp"
+#include "audio/track_queue.hpp"
+#include "drivers/bluetooth.hpp"
+#include "dev_console/console.hpp"
+#include "database/database.hpp"
+#include "drivers/samd.hpp"
+#include "system_fsm/service_locator.hpp"
 
 namespace console {
 
diff --git a/src/audio/README.md b/src/tangara/audio/README.md
index 218be2c4..218be2c4 100644
--- a/src/audio/README.md
+++ b/src/tangara/audio/README.md
diff --git a/src/tangara/audio/audio_decoder.cpp b/src/tangara/audio/audio_decoder.cpp
new file mode 100644
index 00000000..ee06d984
--- /dev/null
+++ b/src/tangara/audio/audio_decoder.cpp
@@ -0,0 +1,199 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "audio/audio_decoder.hpp"
+
+#include <cassert>
+#include <cmath>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <deque>
+#include <memory>
+#include <span>
+#include <variant>
+
+#include "esp_err.h"
+#include "esp_heap_caps.h"
+#include "esp_log.h"
+#include "freertos/portmacro.h"
+#include "freertos/projdefs.h"
+#include "freertos/queue.h"
+
+#include "audio/audio_events.hpp"
+#include "audio/audio_fsm.hpp"
+#include "audio/audio_sink.hpp"
+#include "audio/audio_source.hpp"
+#include "audio/processor.hpp"
+#include "codec.hpp"
+#include "database/track.hpp"
+#include "drivers/i2s_dac.hpp"
+#include "events/event_queue.hpp"
+#include "sample.hpp"
+#include "tasks.hpp"
+#include "types.hpp"
+#include "ui/ui_fsm.hpp"
+
+namespace audio {
+
+static const char* kTag = "decoder";
+
+/*
+ * The size of the buffer used for holding decoded samples. This buffer is
+ * allocated in internal memory for greater speed, so be careful when
+ * increasing its size.
+ */
+static constexpr std::size_t kCodecBufferLength =
+    drivers::kI2SBufferLengthFrames * sizeof(sample::Sample);
+
+auto Decoder::Start(std::shared_ptr<SampleProcessor> sink) -> Decoder* {
+  Decoder* task = new Decoder(sink);
+  tasks::StartPersistent<tasks::Type::kAudioDecoder>([=]() { task->Main(); });
+  return task;
+}
+
+auto Decoder::open(std::shared_ptr<TaggedStream> stream) -> void {
+  NextStream* next = new NextStream();
+  next->stream = stream;
+  // The decoder services its queue very quickly, so blocking on this write
+  // should be fine. If we discover contention here, then adding more space for
+  // items to next_stream_ should be fine too.
+  xQueueSend(next_stream_, &next, portMAX_DELAY);
+}
+
+Decoder::Decoder(std::shared_ptr<SampleProcessor> processor)
+    : processor_(processor), next_stream_(xQueueCreate(1, sizeof(void*))) {
+  ESP_LOGI(kTag, "allocating codec buffer, %u KiB", kCodecBufferLength / 1024);
+  codec_buffer_ = {
+      reinterpret_cast<sample::Sample*>(heap_caps_calloc(
+          kCodecBufferLength, sizeof(sample::Sample), MALLOC_CAP_DMA)),
+      kCodecBufferLength};
+}
+
+/*
+ * Main decoding loop. Handles watching for new streams, or continuing to nudge
+ * along the current stream if we have one.
+ */
+void Decoder::Main() {
+  for (;;) {
+    // Check whether there's a new stream to begin. If we're idle, then we
+    // simply park and wait forever for a stream to arrive.
+    TickType_t wait_time = stream_ ? 0 : portMAX_DELAY;
+    NextStream* next;
+    if (xQueueReceive(next_stream_, &next, wait_time)) {
+      // Copy the data out of the queue, then clean up the item.
+      std::shared_ptr<TaggedStream> new_stream = next->stream;
+      delete next;
+
+      // If we were already decoding, then make sure we finish up the current
+      // file gracefully.
+      if (stream_) {
+        finishDecode(true);
+      }
+
+      // Ensure there's actually stream data; we might have been given nullptr
+      // as a signal to stop.
+      if (!new_stream) {
+        continue;
+      }
+
+      // Start decoding the new stream.
+      prepareDecode(new_stream);
+    }
+
+    if (!continueDecode()) {
+      finishDecode(false);
+    }
+  }
+}
+
+auto Decoder::prepareDecode(std::shared_ptr<TaggedStream> stream) -> void {
+  auto stub_track = std::make_shared<TrackInfo>(TrackInfo{
+      .tags = stream->tags(),
+      .uri = stream->Filepath(),
+      .duration = {},
+      .start_offset = {},
+      .bitrate_kbps = {},
+      .encoding = stream->type(),
+      .format = {},
+  });
+
+  codec_.reset(codecs::CreateCodecForType(stream->type()).value_or(nullptr));
+  if (!codec_) {
+    ESP_LOGE(kTag, "no codec found for stream");
+    events::Audio().Dispatch(
+        internal::DecodingFailedToStart{.track = stub_track});
+    return;
+  }
+
+  auto open_res = codec_->OpenStream(stream, stream->Offset());
+  if (open_res.has_error()) {
+    ESP_LOGE(kTag, "codec failed to start: %s",
+             codecs::ICodec::ErrorString(open_res.error()).c_str());
+    events::Audio().Dispatch(
+        internal::DecodingFailedToStart{.track = stub_track});
+    return;
+  }
+
+  // Decoding started okay! Fill out the rest of the track info for this
+  // stream.
+  stream_ = stream;
+  track_ = std::make_shared<TrackInfo>(TrackInfo{
+      .tags = stream->tags(),
+      .uri = stream->Filepath(),
+      .duration = {},
+      .start_offset = stream->Offset(),
+      .bitrate_kbps = {},
+      .encoding = stream->type(),
+      .format =
+          {
+              .sample_rate = open_res->sample_rate_hz,
+              .num_channels = open_res->num_channels,
+              .bits_per_sample = 16,
+          },
+  });
+
+  if (open_res->total_samples) {
+    track_->duration = open_res->total_samples.value() /
+                       open_res->num_channels / open_res->sample_rate_hz;
+  }
+
+  events::Audio().Dispatch(internal::DecodingStarted{.track = track_});
+  processor_->beginStream(track_);
+}
+
+auto Decoder::continueDecode() -> bool {
+  auto res = codec_->DecodeTo(codec_buffer_);
+  if (res.has_error()) {
+    return false;
+  }
+
+  if (res->samples_written > 0) {
+    processor_->continueStream(codec_buffer_.first(res->samples_written));
+  }
+
+  return !res->is_stream_finished;
+}
+
+auto Decoder::finishDecode(bool cancel) -> void {
+  assert(track_);
+
+  // Tell everyone we're finished.
+  if (cancel) {
+    events::Audio().Dispatch(internal::DecodingCancelled{.track = track_});
+  } else {
+    events::Audio().Dispatch(internal::DecodingFinished{.track = track_});
+  }
+  processor_->endStream(cancel);
+
+  // Clean up after ourselves.
+  stream_.reset();
+  codec_.reset();
+  track_.reset();
+}
+
+}  // namespace audio
diff --git a/src/tangara/audio/audio_decoder.hpp b/src/tangara/audio/audio_decoder.hpp
new file mode 100644
index 00000000..64561d9d
--- /dev/null
+++ b/src/tangara/audio/audio_decoder.hpp
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <memory>
+
+#include "audio/audio_events.hpp"
+#include "audio/audio_sink.hpp"
+#include "audio/audio_source.hpp"
+#include "audio/processor.hpp"
+#include "codec.hpp"
+#include "database/track.hpp"
+#include "types.hpp"
+
+namespace audio {
+
+/*
+ * Handle to a persistent task that takes encoded bytes from arbitrary sources,
+ * decodes them into sample::Sample (normalised to 16 bit signed PCM), and then
+ * streams them onward to the sample processor.
+ */
+class Decoder {
+ public:
+  static auto Start(std::shared_ptr<SampleProcessor>) -> Decoder*;
+
+  auto open(std::shared_ptr<TaggedStream>) -> void;
+
+  Decoder(const Decoder&) = delete;
+  Decoder& operator=(const Decoder&) = delete;
+
+ private:
+  Decoder(std::shared_ptr<SampleProcessor>);
+
+  auto Main() -> void;
+
+  auto prepareDecode(std::shared_ptr<TaggedStream>) -> void;
+  auto continueDecode() -> bool;
+  auto finishDecode(bool cancel) -> void;
+
+  std::shared_ptr<SampleProcessor> processor_;
+
+  // Struct used with the next_stream_ queue.
+  struct NextStream {
+    std::shared_ptr<TaggedStream> stream;
+  };
+  QueueHandle_t next_stream_;
+
+  std::shared_ptr<codecs::IStream> stream_;
+  std::unique_ptr<codecs::ICodec> codec_;
+  std::shared_ptr<TrackInfo> track_;
+
+  std::span<sample::Sample> codec_buffer_;
+};
+
+}  // namespace audio
diff --git a/src/audio/include/audio_events.hpp b/src/tangara/audio/audio_events.hpp
index b8a0dba6..f7eaba67 100644
--- a/src/audio/include/audio_events.hpp
+++ b/src/tangara/audio/audio_events.hpp
@@ -12,10 +12,10 @@
 #include <optional>
 #include <string>
 
-#include "audio_sink.hpp"
+#include "audio/audio_sink.hpp"
 #include "tinyfsm.hpp"
 
-#include "track.hpp"
+#include "database/track.hpp"
 #include "types.hpp"
 
 namespace audio {
@@ -84,13 +84,6 @@ struct PlaybackUpdate : tinyfsm::Event {
 struct SetTrack : tinyfsm::Event {
   std::variant<std::string, database::TrackId, std::monostate> new_track;
   std::optional<uint32_t> seek_to_second;
-
-  enum Transition {
-    kHardCut,
-    kGapless,
-    // TODO: kCrossFade
-  };
-  Transition transition;
 };
 
 struct TogglePlayPause : tinyfsm::Event {
@@ -138,17 +131,33 @@ struct OutputModeChanged : tinyfsm::Event {};
 
 namespace internal {
 
+struct DecodingStarted : tinyfsm::Event {
+  std::shared_ptr<TrackInfo> track;
+};
+
+struct DecodingFailedToStart : tinyfsm::Event {
+  std::shared_ptr<TrackInfo> track;
+};
+
+struct DecodingCancelled : tinyfsm::Event {
+  std::shared_ptr<TrackInfo> track;
+};
+
+struct DecodingFinished : tinyfsm::Event {
+  std::shared_ptr<TrackInfo> track;
+};
+
 struct StreamStarted : tinyfsm::Event {
   std::shared_ptr<TrackInfo> track;
-  IAudioOutput::Format src_format;
-  IAudioOutput::Format dst_format;
+  IAudioOutput::Format sink_format;
+  uint32_t cue_at_sample;
 };
 
-struct StreamUpdate : tinyfsm::Event {
-  uint32_t samples_sunk;
+struct StreamEnded : tinyfsm::Event {
+  uint32_t cue_at_sample;
 };
 
-struct StreamEnded : tinyfsm::Event {};
+struct StreamHeartbeat : tinyfsm::Event {};
 
 }  // namespace internal
 
diff --git a/src/audio/audio_fsm.cpp b/src/tangara/audio/audio_fsm.cpp
index ffb462f8..71f41938 100644
--- a/src/audio/audio_fsm.cpp
+++ b/src/tangara/audio/audio_fsm.cpp
@@ -4,15 +4,13 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "audio_fsm.hpp"
-#include <stdint.h>
+#include "audio/audio_fsm.hpp"
 
+#include <cstdint>
 #include <future>
 #include <memory>
 #include <variant>
 
-#include "audio_sink.hpp"
-#include "bluetooth_types.hpp"
 #include "cppbor.h"
 #include "cppbor_parse.h"
 #include "esp_heap_caps.h"
@@ -20,25 +18,28 @@
 #include "freertos/FreeRTOS.h"
 #include "freertos/portmacro.h"
 #include "freertos/projdefs.h"
+#include "tinyfsm.hpp"
 
-#include "audio_converter.hpp"
-#include "audio_decoder.hpp"
-#include "audio_events.hpp"
-#include "bluetooth.hpp"
-#include "bt_audio_output.hpp"
-#include "event_queue.hpp"
-#include "fatfs_audio_input.hpp"
-#include "future_fetcher.hpp"
-#include "i2s_audio_output.hpp"
-#include "i2s_dac.hpp"
-#include "nvs.hpp"
+#include "audio/audio_decoder.hpp"
+#include "audio/audio_events.hpp"
+#include "audio/audio_sink.hpp"
+#include "audio/bt_audio_output.hpp"
+#include "audio/fatfs_stream_factory.hpp"
+#include "audio/i2s_audio_output.hpp"
+#include "audio/stream_cues.hpp"
+#include "audio/track_queue.hpp"
+#include "database/future_fetcher.hpp"
+#include "database/track.hpp"
+#include "drivers/bluetooth.hpp"
+#include "drivers/bluetooth_types.hpp"
+#include "drivers/i2s_dac.hpp"
+#include "drivers/nvs.hpp"
+#include "drivers/storage.hpp"
+#include "drivers/wm8523.hpp"
+#include "events/event_queue.hpp"
 #include "sample.hpp"
-#include "service_locator.hpp"
-#include "system_events.hpp"
-#include "tinyfsm.hpp"
-#include "track.hpp"
-#include "track_queue.hpp"
-#include "wm8523.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "system_fsm/system_events.hpp"
 
 namespace audio {
 
@@ -46,12 +47,14 @@ namespace audio {
 
 std::shared_ptr<system_fsm::ServiceLocator> AudioState::sServices;
 
-std::shared_ptr<FatfsAudioInput> AudioState::sFileSource;
+std::shared_ptr<FatfsStreamFactory> AudioState::sStreamFactory;
+
 std::unique_ptr<Decoder> AudioState::sDecoder;
-std::shared_ptr<SampleConverter> AudioState::sSampleConverter;
+std::shared_ptr<SampleProcessor> AudioState::sSampleProcessor;
+
+std::shared_ptr<IAudioOutput> AudioState::sOutput;
 std::shared_ptr<I2SAudioOutput> AudioState::sI2SOutput;
 std::shared_ptr<BluetoothAudioOutput> AudioState::sBtOutput;
-std::shared_ptr<IAudioOutput> AudioState::sOutput;
 
 // Two seconds of samples for two channels, at a representative sample rate.
 constexpr size_t kDrainLatencySamples = 48000 * 2 * 2;
@@ -61,30 +64,33 @@ constexpr size_t kDrainBufferSize =
 StreamBufferHandle_t AudioState::sDrainBuffer;
 std::optional<IAudioOutput::Format> AudioState::sDrainFormat;
 
-std::shared_ptr<TrackInfo> AudioState::sCurrentTrack;
-uint64_t AudioState::sCurrentSamples;
-bool AudioState::sCurrentTrackIsFromQueue;
+StreamCues AudioState::sStreamCues;
 
-std::shared_ptr<TrackInfo> AudioState::sNextTrack;
-uint64_t AudioState::sNextTrackCueSamples;
-bool AudioState::sNextTrackIsFromQueue;
-
-bool AudioState::sIsResampling;
 bool AudioState::sIsPaused = true;
 
-auto AudioState::currentPositionSeconds() -> std::optional<uint32_t> {
-  if (!sCurrentTrack || !sDrainFormat) {
-    return {};
+auto AudioState::emitPlaybackUpdate(bool paused) -> void {
+  std::optional<uint32_t> position;
+  auto current = sStreamCues.current();
+  if (current.first && sDrainFormat) {
+    position = (current.second /
+                (sDrainFormat->num_channels * sDrainFormat->sample_rate)) +
+               current.first->start_offset.value_or(0);
   }
-  return sCurrentSamples /
-         (sDrainFormat->num_channels * sDrainFormat->sample_rate);
+
+  PlaybackUpdate event{
+      .current_track = current.first,
+      .track_position = position,
+      .paused = paused,
+  };
+
+  events::System().Dispatch(event);
+  events::Ui().Dispatch(event);
 }
 
 void AudioState::react(const QueueUpdate& ev) {
   SetTrack cmd{
       .new_track = std::monostate{},
       .seek_to_second = {},
-      .transition = SetTrack::Transition::kHardCut,
   };
 
   auto current = sServices->track_queue().current();
@@ -97,20 +103,13 @@ void AudioState::react(const QueueUpdate& ev) {
       if (!ev.current_changed) {
         return;
       }
-      sNextTrackIsFromQueue = true;
-      cmd.transition = SetTrack::Transition::kHardCut;
       break;
     case QueueUpdate::kRepeatingLastTrack:
-      sNextTrackIsFromQueue = true;
-      cmd.transition = SetTrack::Transition::kGapless;
       break;
     case QueueUpdate::kTrackFinished:
       if (!ev.current_changed) {
         cmd.new_track = std::monostate{};
-      } else {
-        sNextTrackIsFromQueue = true;
       }
-      cmd.transition = SetTrack::Transition::kGapless;
       break;
     case QueueUpdate::kDeserialised:
     default:
@@ -123,32 +122,9 @@ void AudioState::react(const QueueUpdate& ev) {
 }
 
 void AudioState::react(const SetTrack& ev) {
-  // Remember the current track if there is one, since we need to preserve some
-  // of the state if it turns out this SetTrack event corresponds to seeking
-  // within the current track.
-  std::string prev_uri;
-  bool prev_from_queue = false;
-  if (sCurrentTrack) {
-    prev_uri = sCurrentTrack->uri;
-    prev_from_queue = sCurrentTrackIsFromQueue;
-  }
-
-  if (ev.transition == SetTrack::Transition::kHardCut) {
-    sCurrentTrack.reset();
-    sCurrentSamples = 0;
-    sCurrentTrackIsFromQueue = false;
-    clearDrainBuffer();
-  }
-
   if (std::holds_alternative<std::monostate>(ev.new_track)) {
     ESP_LOGI(kTag, "playback finished, awaiting drain");
-    sFileSource->SetPath();
-    awaitEmptyDrainBuffer();
-    sCurrentTrack.reset();
-    sDrainFormat.reset();
-    sCurrentSamples = 0;
-    sCurrentTrackIsFromQueue = false;
-    transit<states::Standby>();
+    sDecoder->open({});
     return;
   }
 
@@ -157,96 +133,76 @@ void AudioState::react(const SetTrack& ev) {
   auto new_track = ev.new_track;
   uint32_t seek_to = ev.seek_to_second.value_or(0);
   sServices->bg_worker().Dispatch<void>([=]() {
-    std::optional<std::string> path;
+    std::shared_ptr<TaggedStream> stream;
     if (std::holds_alternative<database::TrackId>(new_track)) {
-      auto db = sServices->database().lock();
-      if (db) {
-        path = db->getTrackPath(std::get<database::TrackId>(new_track));
-      }
+      stream = sStreamFactory->create(std::get<database::TrackId>(new_track),
+                                      seek_to);
     } else if (std::holds_alternative<std::string>(new_track)) {
-      path = std::get<std::string>(new_track);
+      stream =
+          sStreamFactory->create(std::get<std::string>(new_track), seek_to);
     }
 
-    if (path) {
-      if (*path == prev_uri) {
-        // This was a seek or replay within the same track; don't forget where
-        // the track originally came from.
-        sNextTrackIsFromQueue = prev_from_queue;
-      }
-      sFileSource->SetPath(*path, seek_to);
-    } else {
-      sFileSource->SetPath();
-    }
+    sDecoder->open(stream);
   });
 }
 
 void AudioState::react(const TogglePlayPause& ev) {
   sIsPaused = !ev.set_to.value_or(sIsPaused);
-  if (!sIsPaused && is_in_state<states::Standby>() && sCurrentTrack) {
+  if (!sIsPaused && is_in_state<states::Standby>() &&
+      sStreamCues.current().first) {
     transit<states::Playback>();
   } else if (sIsPaused && is_in_state<states::Playback>()) {
     transit<states::Standby>();
   }
 }
 
-void AudioState::react(const internal::StreamStarted& ev) {
-  sDrainFormat = ev.dst_format;
-  sIsResampling = ev.src_format != ev.dst_format;
-
-  sNextTrack = ev.track;
-  sNextTrackCueSamples = sCurrentSamples + (kDrainLatencySamples / 2);
-
-  ESP_LOGI(kTag, "new stream %s %u ch @ %lu hz (resample=%i)",
-           ev.track->uri.c_str(), sDrainFormat->num_channels,
-           sDrainFormat->sample_rate, sIsResampling);
-}
-
-void AudioState::react(const internal::StreamEnded&) {
-  ESP_LOGI(kTag, "stream ended");
-
-  if (sCurrentTrackIsFromQueue) {
-    sServices->track_queue().finish();
-  } else {
-    tinyfsm::FsmList<AudioState>::dispatch(SetTrack{
-        .new_track = std::monostate{},
-        .seek_to_second = {},
-        .transition = SetTrack::Transition::kGapless,
-    });
-  }
+void AudioState::react(const internal::DecodingFinished& ev) {
+  // If we just finished playing whatever's at the front of the queue, then we
+  // need to advanve and start playing the next one ASAP in order to continue
+  // gaplessly.
+  sServices->bg_worker().Dispatch<void>([=]() {
+    auto& queue = sServices->track_queue();
+    auto current = queue.current();
+    if (!current) {
+      return;
+    }
+    auto db = sServices->database().lock();
+    if (!db) {
+      return;
+    }
+    auto path = db->getTrackPath(*current);
+    if (!path) {
+      return;
+    }
+    if (*path == ev.track->uri) {
+      queue.finish();
+    }
+  });
 }
 
-void AudioState::react(const internal::StreamUpdate& ev) {
-  sCurrentSamples += ev.samples_sunk;
-
-  if (sNextTrack && sCurrentSamples >= sNextTrackCueSamples) {
-    ESP_LOGI(kTag, "next track is now sinking");
-    sCurrentTrack = sNextTrack;
-    sCurrentSamples -= sNextTrackCueSamples;
-    sCurrentSamples += sNextTrack->start_offset.value_or(0) *
-                       (sDrainFormat->num_channels * sDrainFormat->sample_rate);
-    sCurrentTrackIsFromQueue = sNextTrackIsFromQueue;
-
-    sNextTrack.reset();
-    sNextTrackCueSamples = 0;
-    sNextTrackIsFromQueue = false;
+void AudioState::react(const internal::StreamStarted& ev) {
+  if (sDrainFormat != ev.sink_format) {
+    sDrainFormat = ev.sink_format;
+    ESP_LOGI(kTag, "sink_format=%u ch @ %lu hz", sDrainFormat->num_channels,
+             sDrainFormat->sample_rate);
   }
 
-  if (sCurrentTrack) {
-    PlaybackUpdate event{
-        .current_track = sCurrentTrack,
-        .track_position = currentPositionSeconds(),
-        .paused = !is_in_state<states::Playback>(),
-    };
-    events::System().Dispatch(event);
-    events::Ui().Dispatch(event);
-  }
+  sStreamCues.addCue(ev.track, ev.cue_at_sample);
 
-  if (sCurrentTrack && !sIsPaused && !is_in_state<states::Playback>()) {
-    ESP_LOGI(kTag, "ready to play!");
+  if (!sIsPaused && !is_in_state<states::Playback>()) {
     transit<states::Playback>();
+  } else {
+    // Make sure everyone knows we've got a track ready to go, even if we're
+    // not playing it yet. This mostly matters when restoring the queue from
+    // disk after booting.
+    emitPlaybackUpdate(true);
   }
 }
 
+void AudioState::react(const internal::StreamEnded& ev) {
+  sStreamCues.addCue({}, ev.cue_at_sample);
+}
+
 void AudioState::react(const system_fsm::BluetoothEvent& ev) {
   if (ev.event != drivers::bluetooth::Event::kConnectionStateChanged) {
     return;
@@ -282,14 +238,6 @@ void AudioState::react(const StepDownVolume& ev) {
   }
 }
 
-void AudioState::react(const system_fsm::HasPhonesChanged& ev) {
-  if (ev.has_headphones) {
-    ESP_LOGI(kTag, "headphones in!");
-  } else {
-    ESP_LOGI(kTag, "headphones out!");
-  }
-}
-
 void AudioState::react(const SetVolume& ev) {
   if (ev.db.has_value()) {
     if (sOutput->SetVolumeDb(ev.db.value())) {
@@ -349,7 +297,7 @@ void AudioState::react(const OutputModeChanged& ev) {
       break;
   }
   sOutput->mode(IAudioOutput::Modes::kOnPaused);
-  sSampleConverter->SetOutput(sOutput);
+  sSampleProcessor->SetOutput(sOutput);
 
   // Bluetooth volume isn't 'changed' until we've connected to a device.
   if (new_mode == drivers::NvsStorage::Output::kHeadphones) {
@@ -360,43 +308,6 @@ void AudioState::react(const OutputModeChanged& ev) {
   }
 }
 
-auto AudioState::clearDrainBuffer() -> void {
-  // Tell the decoder to stop adding new samples. This might not take effect
-  // immediately, since the decoder might currently be stuck waiting for space
-  // to become available in the drain buffer.
-  sFileSource->SetPath();
-
-  auto mode = sOutput->mode();
-  if (mode == IAudioOutput::Modes::kOnPlaying) {
-    // If we're currently playing, then the drain buffer will be actively
-    // draining on its own. Just keep trying to reset until it works.
-    while (xStreamBufferReset(sDrainBuffer) != pdPASS) {
-    }
-  } else {
-    // If we're not currently playing, then we need to actively pull samples
-    // out of the drain buffer to unblock the decoder.
-    while (!xStreamBufferIsEmpty(sDrainBuffer)) {
-      // Read a little to unblock the decoder.
-      uint8_t drain[2048];
-      xStreamBufferReceive(sDrainBuffer, drain, sizeof(drain), 0);
-
-      // Try to quickly discard the rest.
-      xStreamBufferReset(sDrainBuffer);
-    }
-  }
-}
-
-auto AudioState::awaitEmptyDrainBuffer() -> void {
-  if (is_in_state<states::Playback>()) {
-    for (int i = 0; i < 10 && !xStreamBufferIsEmpty(sDrainBuffer); i++) {
-      vTaskDelay(pdMS_TO_TICKS(250));
-    }
-  }
-  if (!xStreamBufferIsEmpty(sDrainBuffer)) {
-    clearDrainBuffer();
-  }
-}
-
 auto AudioState::commitVolume() -> void {
   auto mode = sServices->nvs().OutputMode();
   auto vol = sOutput->GetVolume();
@@ -427,8 +338,7 @@ void Uninitialised::react(const system_fsm::BootComplete& ev) {
   sDrainBuffer = xStreamBufferCreateStatic(
       kDrainBufferSize, sizeof(sample::Sample), storage, meta);
 
-  sFileSource.reset(
-      new FatfsAudioInput(sServices->tag_parser(), sServices->bg_worker()));
+  sStreamFactory.reset(new FatfsStreamFactory(*sServices));
   sI2SOutput.reset(new I2SAudioOutput(sDrainBuffer, sServices->gpios()));
   sBtOutput.reset(new BluetoothAudioOutput(sDrainBuffer, sServices->bluetooth(),
                                            sServices->bg_worker()));
@@ -462,10 +372,10 @@ void Uninitialised::react(const system_fsm::BootComplete& ev) {
       .left_bias = nvs.AmpLeftBias(),
   });
 
-  sSampleConverter.reset(new SampleConverter());
-  sSampleConverter->SetOutput(sOutput);
+  sSampleProcessor.reset(new SampleProcessor(sDrainBuffer));
+  sSampleProcessor->SetOutput(sOutput);
 
-  Decoder::Start(sFileSource, sSampleConverter);
+  sDecoder.reset(Decoder::Start(sSampleProcessor));
 
   transit<Standby>();
 }
@@ -477,7 +387,8 @@ void Standby::react(const system_fsm::KeyLockChanged& ev) {
   if (!ev.locking) {
     return;
   }
-  sServices->bg_worker().Dispatch<void>([this]() {
+  auto current = sStreamCues.current();
+  sServices->bg_worker().Dispatch<void>([=]() {
     auto db = sServices->database().lock();
     if (!db) {
       return;
@@ -490,17 +401,24 @@ void Standby::react(const system_fsm::KeyLockChanged& ev) {
     }
     db->put(kQueueKey, queue.serialise());
 
-    if (sCurrentTrack) {
+    if (current.first && sDrainFormat) {
+      uint32_t seconds = (current.second / (sDrainFormat->num_channels *
+                                            sDrainFormat->sample_rate)) +
+                         current.first->start_offset.value_or(0);
       cppbor::Array current_track{
-          cppbor::Tstr{sCurrentTrack->uri},
-          cppbor::Uint{currentPositionSeconds().value_or(0)},
+          cppbor::Tstr{current.first->uri},
+          cppbor::Uint{seconds},
       };
       db->put(kCurrentFileKey, current_track.toString());
     }
   });
 }
 
-void Standby::react(const system_fsm::StorageMounted& ev) {
+void Standby::react(const system_fsm::SdStateChanged& ev) {
+  auto state = sServices->sd();
+  if (state != drivers::SdState::kMounted) {
+    return;
+  }
   sServices->bg_worker().Dispatch<void>([]() {
     auto db = sServices->database().lock();
     if (!db) {
@@ -524,7 +442,6 @@ void Standby::react(const system_fsm::StorageMounted& ev) {
         events::Audio().Dispatch(SetTrack{
             .new_track = filename,
             .seek_to_second = pos,
-            .transition = SetTrack::Transition::kHardCut,
         });
       }
     }
@@ -540,32 +457,47 @@ void Standby::react(const system_fsm::StorageMounted& ev) {
   });
 }
 
+static TimerHandle_t sHeartbeatTimer;
+
+static void heartbeat(TimerHandle_t) {
+  events::Audio().Dispatch(internal::StreamHeartbeat{});
+}
+
 void Playback::entry() {
   ESP_LOGI(kTag, "audio output resumed");
   sOutput->mode(IAudioOutput::Modes::kOnPlaying);
+  emitPlaybackUpdate(false);
 
-  PlaybackUpdate event{
-      .current_track = sCurrentTrack,
-      .track_position = currentPositionSeconds(),
-      .paused = false,
-  };
-
-  events::System().Dispatch(event);
-  events::Ui().Dispatch(event);
+  if (!sHeartbeatTimer) {
+    sHeartbeatTimer =
+        xTimerCreate("stream", pdMS_TO_TICKS(250), true, NULL, heartbeat);
+  }
+  xTimerStart(sHeartbeatTimer, portMAX_DELAY);
 }
 
 void Playback::exit() {
   ESP_LOGI(kTag, "audio output paused");
+  xTimerStop(sHeartbeatTimer, portMAX_DELAY);
   sOutput->mode(IAudioOutput::Modes::kOnPaused);
+  emitPlaybackUpdate(true);
+}
 
-  PlaybackUpdate event{
-      .current_track = sCurrentTrack,
-      .track_position = currentPositionSeconds(),
-      .paused = true,
-  };
+void Playback::react(const system_fsm::SdStateChanged& ev) {
+  if (sServices->sd() != drivers::SdState::kMounted) {
+    transit<Standby>();
+  }
+}
 
-  events::System().Dispatch(event);
-  events::Ui().Dispatch(event);
+void Playback::react(const internal::StreamHeartbeat& ev) {
+  sStreamCues.update(sOutput->samplesUsed());
+
+  if (sStreamCues.hasStream()) {
+    emitPlaybackUpdate(false);
+  } else {
+    // Finished the current stream, and there's nothing upcoming. We must be
+    // finished.
+    transit<Standby>();
+  }
 }
 
 }  // namespace states
diff --git a/src/audio/include/audio_fsm.hpp b/src/tangara/audio/audio_fsm.hpp
index 60afb321..03aaddcb 100644
--- a/src/audio/include/audio_fsm.hpp
+++ b/src/tangara/audio/audio_fsm.hpp
@@ -11,24 +11,25 @@
 #include <memory>
 #include <vector>
 
-#include "audio_sink.hpp"
-#include "service_locator.hpp"
+#include "audio/stream_cues.hpp"
 #include "tinyfsm.hpp"
 
-#include "audio_decoder.hpp"
-#include "audio_events.hpp"
-#include "bt_audio_output.hpp"
-#include "database.hpp"
-#include "display.hpp"
-#include "fatfs_audio_input.hpp"
-#include "gpios.hpp"
-#include "i2s_audio_output.hpp"
-#include "i2s_dac.hpp"
-#include "storage.hpp"
-#include "system_events.hpp"
-#include "tag_parser.hpp"
-#include "track.hpp"
-#include "track_queue.hpp"
+#include "audio/audio_decoder.hpp"
+#include "audio/audio_events.hpp"
+#include "audio/audio_sink.hpp"
+#include "audio/bt_audio_output.hpp"
+#include "audio/fatfs_stream_factory.hpp"
+#include "audio/i2s_audio_output.hpp"
+#include "audio/track_queue.hpp"
+#include "database/database.hpp"
+#include "database/tag_parser.hpp"
+#include "database/track.hpp"
+#include "drivers/display.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/i2s_dac.hpp"
+#include "drivers/storage.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "system_fsm/system_events.hpp"
 
 namespace audio {
 
@@ -46,13 +47,13 @@ class AudioState : public tinyfsm::Fsm<AudioState> {
   void react(const SetTrack&);
   void react(const TogglePlayPause&);
 
+  void react(const internal::DecodingFinished&);
   void react(const internal::StreamStarted&);
-  void react(const internal::StreamUpdate&);
   void react(const internal::StreamEnded&);
+  virtual void react(const internal::StreamHeartbeat&) {}
 
   void react(const StepUpVolume&);
   void react(const StepDownVolume&);
-  virtual void react(const system_fsm::HasPhonesChanged&);
 
   void react(const SetVolume&);
   void react(const SetVolumeLimit&);
@@ -62,40 +63,28 @@ class AudioState : public tinyfsm::Fsm<AudioState> {
 
   virtual void react(const system_fsm::BootComplete&) {}
   virtual void react(const system_fsm::KeyLockChanged&){};
-  virtual void react(const system_fsm::StorageMounted&) {}
+  virtual void react(const system_fsm::SdStateChanged&) {}
   virtual void react(const system_fsm::BluetoothEvent&);
 
  protected:
-  auto clearDrainBuffer() -> void;
-  auto awaitEmptyDrainBuffer() -> void;
-
-  auto playTrack(database::TrackId id) -> void;
+  auto emitPlaybackUpdate(bool paused) -> void;
   auto commitVolume() -> void;
 
   static std::shared_ptr<system_fsm::ServiceLocator> sServices;
 
-  static std::shared_ptr<FatfsAudioInput> sFileSource;
+  static std::shared_ptr<FatfsStreamFactory> sStreamFactory;
   static std::unique_ptr<Decoder> sDecoder;
-  static std::shared_ptr<SampleConverter> sSampleConverter;
+  static std::shared_ptr<SampleProcessor> sSampleProcessor;
   static std::shared_ptr<I2SAudioOutput> sI2SOutput;
   static std::shared_ptr<BluetoothAudioOutput> sBtOutput;
   static std::shared_ptr<IAudioOutput> sOutput;
 
   static StreamBufferHandle_t sDrainBuffer;
 
-  static std::shared_ptr<TrackInfo> sCurrentTrack;
-  static uint64_t sCurrentSamples;
+  static StreamCues sStreamCues;
   static std::optional<IAudioOutput::Format> sDrainFormat;
-  static bool sCurrentTrackIsFromQueue;
-
-  static std::shared_ptr<TrackInfo> sNextTrack;
-  static uint64_t sNextTrackCueSamples;
-  static bool sNextTrackIsFromQueue;
 
-  static bool sIsResampling;
   static bool sIsPaused;
-
-  auto currentPositionSeconds() -> std::optional<uint32_t>;
 };
 
 namespace states {
@@ -111,7 +100,7 @@ class Uninitialised : public AudioState {
 class Standby : public AudioState {
  public:
   void react(const system_fsm::KeyLockChanged&) override;
-  void react(const system_fsm::StorageMounted&) override;
+  void react(const system_fsm::SdStateChanged&) override;
 
   using AudioState::react;
 };
@@ -121,6 +110,9 @@ class Playback : public AudioState {
   void entry() override;
   void exit() override;
 
+  void react(const system_fsm::SdStateChanged&) override;
+  void react(const internal::StreamHeartbeat&) override;
+
   using AudioState::react;
 };
 
diff --git a/src/audio/include/audio_sink.hpp b/src/tangara/audio/audio_sink.hpp
index f31d0d75..0b133a8d 100644
--- a/src/audio/include/audio_sink.hpp
+++ b/src/tangara/audio/audio_sink.hpp
@@ -75,6 +75,7 @@ class IAudioOutput {
 
   virtual auto PrepareFormat(const Format&) -> Format = 0;
   virtual auto Configure(const Format& format) -> void = 0;
+  virtual auto samplesUsed() -> uint32_t = 0;
 
   auto stream() -> StreamBufferHandle_t { return stream_; }
 
diff --git a/src/audio/audio_source.cpp b/src/tangara/audio/audio_source.cpp
index d9e8e04a..4989c470 100644
--- a/src/audio/audio_source.cpp
+++ b/src/tangara/audio/audio_source.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "audio_source.hpp"
+#include "audio/audio_source.hpp"
 #include "codec.hpp"
 #include "types.hpp"
 
@@ -14,13 +14,17 @@ TaggedStream::TaggedStream(std::shared_ptr<database::TrackTags> t,
                            std::unique_ptr<codecs::IStream> w,
                            std::string filepath,
                            uint32_t offset)
-    : codecs::IStream(w->type()), tags_(t), wrapped_(std::move(w)), filepath_(filepath), offset_(offset) {}
+    : codecs::IStream(w->type()),
+      tags_(t),
+      wrapped_(std::move(w)),
+      filepath_(filepath),
+      offset_(offset) {}
 
 auto TaggedStream::tags() -> std::shared_ptr<database::TrackTags> {
   return tags_;
 }
 
-auto TaggedStream::Read(cpp::span<std::byte> dest) -> ssize_t {
+auto TaggedStream::Read(std::span<std::byte> dest) -> ssize_t {
   return wrapped_->Read(dest);
 }
 
diff --git a/src/audio/include/audio_source.hpp b/src/tangara/audio/audio_source.hpp
index b38acd7a..2433da46 100644
--- a/src/audio/include/audio_source.hpp
+++ b/src/tangara/audio/audio_source.hpp
@@ -8,7 +8,7 @@
 
 #include <memory>
 #include "codec.hpp"
-#include "track.hpp"
+#include "database/track.hpp"
 #include "types.hpp"
 
 namespace audio {
@@ -18,12 +18,11 @@ class TaggedStream : public codecs::IStream {
   TaggedStream(std::shared_ptr<database::TrackTags>,
                std::unique_ptr<codecs::IStream> wrapped,
                std::string path,
-               uint32_t offset = 0
-              );
+               uint32_t offset = 0);
 
   auto tags() -> std::shared_ptr<database::TrackTags>;
 
-  auto Read(cpp::span<std::byte> dest) -> ssize_t override;
+  auto Read(std::span<std::byte> dest) -> ssize_t override;
 
   auto CanSeek() -> bool override;
 
diff --git a/src/audio/bt_audio_output.cpp b/src/tangara/audio/bt_audio_output.cpp
index 229a38bb..f1b4c26c 100644
--- a/src/audio/bt_audio_output.cpp
+++ b/src/tangara/audio/bt_audio_output.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "bt_audio_output.hpp"
+#include "audio/bt_audio_output.hpp"
 
 #include <algorithm>
 #include <cmath>
@@ -18,12 +18,12 @@
 #include "freertos/portmacro.h"
 #include "freertos/projdefs.h"
 
-#include "gpios.hpp"
-#include "i2c.hpp"
-#include "i2s_dac.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/i2c.hpp"
+#include "drivers/i2s_dac.hpp"
+#include "drivers/wm8523.hpp"
 #include "result.hpp"
 #include "tasks.hpp"
-#include "wm8523.hpp"
 
 [[maybe_unused]] static const char* kTag = "BTOUT";
 
@@ -121,4 +121,8 @@ auto BluetoothAudioOutput::Configure(const Format& fmt) -> void {
   // No configuration necessary; the output format is fixed.
 }
 
+auto BluetoothAudioOutput::samplesUsed() -> uint32_t {
+  return bluetooth_.SamplesUsed();
+}
+
 }  // namespace audio
diff --git a/src/audio/include/bt_audio_output.hpp b/src/tangara/audio/bt_audio_output.hpp
index cc3b2462..c5681f9a 100644
--- a/src/audio/include/bt_audio_output.hpp
+++ b/src/tangara/audio/bt_audio_output.hpp
@@ -13,10 +13,10 @@
 
 #include "result.hpp"
 
-#include "audio_sink.hpp"
-#include "bluetooth.hpp"
-#include "gpios.hpp"
-#include "i2s_dac.hpp"
+#include "audio/audio_sink.hpp"
+#include "drivers/bluetooth.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/i2s_dac.hpp"
 #include "tasks.hpp"
 
 namespace audio {
@@ -45,6 +45,8 @@ class BluetoothAudioOutput : public IAudioOutput {
   auto PrepareFormat(const Format&) -> Format override;
   auto Configure(const Format& format) -> void override;
 
+  auto samplesUsed() -> uint32_t override;
+
   BluetoothAudioOutput(const BluetoothAudioOutput&) = delete;
   BluetoothAudioOutput& operator=(const BluetoothAudioOutput&) = delete;
 
diff --git a/src/audio/fatfs_source.cpp b/src/tangara/audio/fatfs_source.cpp
index 72c3940d..fb6a684d 100644
--- a/src/audio/fatfs_source.cpp
+++ b/src/tangara/audio/fatfs_source.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "fatfs_source.hpp"
+#include "audio/fatfs_source.hpp"
 #include <sys/_stdint.h>
 
 #include <cstddef>
@@ -12,13 +12,13 @@
 #include <memory>
 
 #include "esp_log.h"
-#include "event_queue.hpp"
+#include "events/event_queue.hpp"
 #include "ff.h"
 
-#include "audio_source.hpp"
+#include "audio/audio_source.hpp"
 #include "codec.hpp"
-#include "spi.hpp"
-#include "system_events.hpp"
+#include "drivers/spi.hpp"
+#include "system_fsm/system_events.hpp"
 #include "types.hpp"
 
 namespace audio {
@@ -33,7 +33,7 @@ FatfsSource::~FatfsSource() {
   f_close(file_.get());
 }
 
-auto FatfsSource::Read(cpp::span<std::byte> dest) -> ssize_t {
+auto FatfsSource::Read(std::span<std::byte> dest) -> ssize_t {
   auto lock = drivers::acquire_spi();
   if (f_eof(file_.get())) {
     return 0;
diff --git a/src/audio/include/fatfs_source.hpp b/src/tangara/audio/fatfs_source.hpp
index 45ab34c6..32650880 100644
--- a/src/audio/include/fatfs_source.hpp
+++ b/src/tangara/audio/fatfs_source.hpp
@@ -13,7 +13,7 @@
 #include "codec.hpp"
 #include "ff.h"
 
-#include "audio_source.hpp"
+#include "audio/audio_source.hpp"
 
 namespace audio {
 
@@ -26,7 +26,7 @@ class FatfsSource : public codecs::IStream {
   FatfsSource(codecs::StreamType, std::unique_ptr<FIL> file);
   ~FatfsSource();
 
-  auto Read(cpp::span<std::byte> dest) -> ssize_t override;
+  auto Read(std::span<std::byte> dest) -> ssize_t override;
 
   auto CanSeek() -> bool override;
 
diff --git a/src/tangara/audio/fatfs_stream_factory.cpp b/src/tangara/audio/fatfs_stream_factory.cpp
new file mode 100644
index 00000000..db08e68c
--- /dev/null
+++ b/src/tangara/audio/fatfs_stream_factory.cpp
@@ -0,0 +1,104 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "audio/fatfs_stream_factory.hpp"
+
+#include <cstdint>
+#include <memory>
+#include <string>
+
+#include "database/database.hpp"
+#include "esp_log.h"
+#include "ff.h"
+#include "freertos/portmacro.h"
+#include "freertos/projdefs.h"
+
+#include "audio/audio_source.hpp"
+#include "audio/fatfs_source.hpp"
+#include "codec.hpp"
+#include "database/tag_parser.hpp"
+#include "database/track.hpp"
+#include "drivers/spi.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "tasks.hpp"
+#include "types.hpp"
+
+[[maybe_unused]] static const char* kTag = "SRC";
+
+namespace audio {
+
+FatfsStreamFactory::FatfsStreamFactory(system_fsm::ServiceLocator& services)
+    : services_(services) {}
+
+auto FatfsStreamFactory::create(database::TrackId id, uint32_t offset)
+    -> std::shared_ptr<TaggedStream> {
+  auto db = services_.database().lock();
+  if (!db) {
+    return {};
+  }
+  auto path = db->getTrackPath(id);
+  if (!path) {
+    return {};
+  }
+  return create(*path, offset);
+}
+
+auto FatfsStreamFactory::create(std::string path, uint32_t offset)
+    -> std::shared_ptr<TaggedStream> {
+  auto tags = services_.tag_parser().ReadAndParseTags(path);
+  if (!tags) {
+    ESP_LOGE(kTag, "failed to read tags");
+    return {};
+  }
+
+  if (!tags->title()) {
+    tags->title(path);
+  }
+
+  auto stream_type = ContainerToStreamType(tags->encoding());
+  if (!stream_type.has_value()) {
+    ESP_LOGE(kTag, "couldn't match container to stream");
+    return {};
+  }
+
+  std::unique_ptr<FIL> file = std::make_unique<FIL>();
+  FRESULT res;
+
+  {
+    auto lock = drivers::acquire_spi();
+    res = f_open(file.get(), path.c_str(), FA_READ);
+  }
+
+  if (res != FR_OK) {
+    ESP_LOGE(kTag, "failed to open file! res: %i", res);
+    return {};
+  }
+
+  return std::make_shared<TaggedStream>(
+      tags, std::make_unique<FatfsSource>(stream_type.value(), std::move(file)),
+      path, offset);
+}
+
+auto FatfsStreamFactory::ContainerToStreamType(database::Container enc)
+    -> std::optional<codecs::StreamType> {
+  switch (enc) {
+    case database::Container::kMp3:
+      return codecs::StreamType::kMp3;
+    case database::Container::kWav:
+      return codecs::StreamType::kWav;
+    case database::Container::kOgg:
+      return codecs::StreamType::kVorbis;
+    case database::Container::kFlac:
+      return codecs::StreamType::kFlac;
+    case database::Container::kOpus:
+      return codecs::StreamType::kOpus;
+    case database::Container::kUnsupported:
+    default:
+      return {};
+  }
+}
+
+}  // namespace audio
diff --git a/src/tangara/audio/fatfs_stream_factory.hpp b/src/tangara/audio/fatfs_stream_factory.hpp
new file mode 100644
index 00000000..858d2131
--- /dev/null
+++ b/src/tangara/audio/fatfs_stream_factory.hpp
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <cstddef>
+#include <cstdint>
+#include <future>
+#include <memory>
+#include <string>
+
+#include "database/database.hpp"
+#include "database/track.hpp"
+#include "ff.h"
+#include "freertos/portmacro.h"
+
+#include "audio/audio_source.hpp"
+#include "codec.hpp"
+#include "database/future_fetcher.hpp"
+#include "database/tag_parser.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "tasks.hpp"
+#include "types.hpp"
+
+namespace audio {
+
+/*
+ * Utility to create streams that read from files on the sd card.
+ */
+class FatfsStreamFactory {
+ public:
+  explicit FatfsStreamFactory(system_fsm::ServiceLocator&);
+
+  auto create(database::TrackId, uint32_t offset = 0)
+      -> std::shared_ptr<TaggedStream>;
+  auto create(std::string, uint32_t offset = 0)
+      -> std::shared_ptr<TaggedStream>;
+
+  FatfsStreamFactory(const FatfsStreamFactory&) = delete;
+  FatfsStreamFactory& operator=(const FatfsStreamFactory&) = delete;
+
+ private:
+  auto ContainerToStreamType(database::Container)
+      -> std::optional<codecs::StreamType>;
+
+  system_fsm::ServiceLocator& services_;
+};
+
+}  // namespace audio
diff --git a/src/audio/i2s_audio_output.cpp b/src/tangara/audio/i2s_audio_output.cpp
index bf1c3e5e..684bfa92 100644
--- a/src/audio/i2s_audio_output.cpp
+++ b/src/tangara/audio/i2s_audio_output.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "i2s_audio_output.hpp"
+#include "audio/i2s_audio_output.hpp"
 #include <stdint.h>
 
 #include <algorithm>
@@ -18,12 +18,12 @@
 #include "freertos/portmacro.h"
 #include "freertos/projdefs.h"
 
-#include "audio_sink.hpp"
-#include "gpios.hpp"
-#include "i2c.hpp"
-#include "i2s_dac.hpp"
+#include "audio/audio_sink.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/i2c.hpp"
+#include "drivers/i2s_dac.hpp"
+#include "drivers/wm8523.hpp"
 #include "result.hpp"
-#include "wm8523.hpp"
 
 [[maybe_unused]] static const char* kTag = "I2SOUT";
 
@@ -120,7 +120,7 @@ auto I2SAudioOutput::SetVolumePct(uint_fast8_t val) -> bool {
   if (val > 100) {
     return false;
   }
-  uint16_t vol = (val * (max_volume_ - kMinVolume))/100 + kMinVolume;
+  uint16_t vol = (val * (max_volume_ - kMinVolume)) / 100 + kMinVolume;
   SetVolume(vol);
   return true;
 }
@@ -133,7 +133,8 @@ auto I2SAudioOutput::GetVolumeDb() -> int_fast16_t {
 }
 
 auto I2SAudioOutput::SetVolumeDb(int_fast16_t val) -> bool {
-  SetVolume(val * 4 + static_cast<int>(drivers::wm8523::kLineLevelReferenceVolume) - 2);
+  SetVolume(val * 4 +
+            static_cast<int>(drivers::wm8523::kLineLevelReferenceVolume) - 2);
   return true;
 }
 
@@ -229,4 +230,8 @@ auto I2SAudioOutput::Configure(const Format& fmt) -> void {
   current_config_ = fmt;
 }
 
+auto I2SAudioOutput::samplesUsed() -> uint32_t {
+  return dac_->SamplesUsed();
+}
+
 }  // namespace audio
diff --git a/src/audio/include/i2s_audio_output.hpp b/src/tangara/audio/i2s_audio_output.hpp
index 7954257a..bd7d62fb 100644
--- a/src/audio/include/i2s_audio_output.hpp
+++ b/src/tangara/audio/i2s_audio_output.hpp
@@ -11,9 +11,9 @@
 #include <memory>
 #include <vector>
 
-#include "audio_sink.hpp"
-#include "gpios.hpp"
-#include "i2s_dac.hpp"
+#include "audio/audio_sink.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/i2s_dac.hpp"
 #include "result.hpp"
 
 namespace audio {
@@ -43,6 +43,8 @@ class I2SAudioOutput : public IAudioOutput {
   auto PrepareFormat(const Format&) -> Format override;
   auto Configure(const Format& format) -> void override;
 
+  auto samplesUsed() -> uint32_t override;
+
   I2SAudioOutput(const I2SAudioOutput&) = delete;
   I2SAudioOutput& operator=(const I2SAudioOutput&) = delete;
 
diff --git a/src/audio/audio_converter.cpp b/src/tangara/audio/processor.cpp
index eb1cde80..dd96c892 100644
--- a/src/audio/audio_converter.cpp
+++ b/src/tangara/audio/processor.cpp
@@ -4,23 +4,24 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "audio_converter.hpp"
+#include "audio/processor.hpp"
 #include <stdint.h>
 
 #include <algorithm>
 #include <cmath>
 #include <cstdint>
+#include <limits>
 
-#include "audio_events.hpp"
-#include "audio_sink.hpp"
+#include "audio/audio_events.hpp"
+#include "audio/audio_sink.hpp"
+#include "drivers/i2s_dac.hpp"
 #include "esp_heap_caps.h"
 #include "esp_log.h"
-#include "event_queue.hpp"
+#include "events/event_queue.hpp"
 #include "freertos/portmacro.h"
 #include "freertos/projdefs.h"
-#include "i2s_dac.hpp"
 
-#include "resample.hpp"
+#include "audio/resample.hpp"
 #include "sample.hpp"
 #include "tasks.hpp"
 
@@ -32,14 +33,15 @@ static constexpr std::size_t kSourceBufferLength = kSampleBufferLength * 2;
 
 namespace audio {
 
-SampleConverter::SampleConverter()
+SampleProcessor::SampleProcessor(StreamBufferHandle_t sink)
     : commands_(xQueueCreate(1, sizeof(Args))),
       resampler_(nullptr),
       source_(xStreamBufferCreateWithCaps(kSourceBufferLength,
                                           sizeof(sample::Sample) * 2,
                                           MALLOC_CAP_DMA)),
+      sink_(sink),
       leftover_bytes_(0),
-      samples_sunk_(0) {
+      samples_written_(0) {
   input_buffer_ = {
       reinterpret_cast<sample::Sample*>(heap_caps_calloc(
           kSampleBufferLength, sizeof(sample::Sample), MALLOC_CAP_DMA)),
@@ -55,47 +57,52 @@ SampleConverter::SampleConverter()
   tasks::StartPersistent<tasks::Type::kAudioConverter>([&]() { Main(); });
 }
 
-SampleConverter::~SampleConverter() {
+SampleProcessor::~SampleProcessor() {
   vQueueDelete(commands_);
   vStreamBufferDelete(source_);
 }
 
-auto SampleConverter::SetOutput(std::shared_ptr<IAudioOutput> output) -> void {
-  // FIXME: We should add synchronisation here, but we should be careful about
-  // not impacting performance given that the output will change only very
-  // rarely (if ever).
-  sink_ = output;
+auto SampleProcessor::SetOutput(std::shared_ptr<IAudioOutput> output) -> void {
+  assert(xStreamBufferIsEmpty(sink_));
+  // FIXME: We should add synchronisation here, but we should be careful
+  // about not impacting performance given that the output will change only
+  // very rarely (if ever).
+  output_ = output;
+  samples_written_ = output_->samplesUsed();
 }
 
-auto SampleConverter::beginStream(std::shared_ptr<TrackInfo> track) -> void {
+auto SampleProcessor::beginStream(std::shared_ptr<TrackInfo> track) -> void {
   Args args{
       .track = new std::shared_ptr<TrackInfo>(track),
       .samples_available = 0,
       .is_end_of_stream = false,
+      .clear_buffers = false,
   };
   xQueueSend(commands_, &args, portMAX_DELAY);
 }
 
-auto SampleConverter::continueStream(cpp::span<sample::Sample> input) -> void {
+auto SampleProcessor::continueStream(std::span<sample::Sample> input) -> void {
   Args args{
       .track = nullptr,
       .samples_available = input.size(),
       .is_end_of_stream = false,
+      .clear_buffers = false,
   };
   xQueueSend(commands_, &args, portMAX_DELAY);
   xStreamBufferSend(source_, input.data(), input.size_bytes(), portMAX_DELAY);
 }
 
-auto SampleConverter::endStream() -> void {
+auto SampleProcessor::endStream(bool cancelled) -> void {
   Args args{
       .track = nullptr,
       .samples_available = 0,
       .is_end_of_stream = true,
+      .clear_buffers = cancelled,
   };
   xQueueSend(commands_, &args, portMAX_DELAY);
 }
 
-auto SampleConverter::Main() -> void {
+auto SampleProcessor::Main() -> void {
   for (;;) {
     Args args;
     while (!xQueueReceive(commands_, &args, portMAX_DELAY)) {
@@ -109,43 +116,44 @@ auto SampleConverter::Main() -> void {
       handleContinueStream(args.samples_available);
     }
     if (args.is_end_of_stream) {
-      handleEndStream();
+      handleEndStream(args.clear_buffers);
     }
   }
 }
 
-auto SampleConverter::handleBeginStream(std::shared_ptr<TrackInfo> track)
+auto SampleProcessor::handleBeginStream(std::shared_ptr<TrackInfo> track)
     -> void {
   if (track->format != source_format_) {
-    resampler_.reset();
     source_format_ = track->format;
+    // The new stream has a different format to the previous stream (or there
+    // was no previous stream).
+    // First, clean up our filters.
+    resampler_.reset();
     leftover_bytes_ = 0;
 
-    auto new_target = sink_->PrepareFormat(track->format);
-    if (new_target != target_format_) {
-      // The new format is different to the old one. Wait for the sink to
-      // drain before continuing.
-      while (!xStreamBufferIsEmpty(sink_->stream())) {
-        ESP_LOGI(kTag, "waiting for sink stream to drain...");
-        // TODO(jacqueline): Get the sink drain ISR to notify us of this
-        // via semaphore instead of busy-ish waiting.
-        vTaskDelay(pdMS_TO_TICKS(10));
-      }
-
-      sink_->Configure(new_target);
+    // If the output is idle, then we can reconfigure it to the closest format
+    // to our new source.
+    // If the output *wasn't* idle, then we can't reconfigure without an
+    // audible gap in playback. So instead, we simply keep the same target
+    // format and begin resampling.
+    if (xStreamBufferIsEmpty(sink_)) {
+      target_format_ = output_->PrepareFormat(track->format);
+      output_->Configure(target_format_);
     }
-    target_format_ = new_target;
   }
 
-  samples_sunk_ = 0;
+  if (xStreamBufferIsEmpty(sink_)) {
+    samples_written_ = output_->samplesUsed();
+  }
+
   events::Audio().Dispatch(internal::StreamStarted{
       .track = track,
-      .src_format = source_format_,
-      .dst_format = target_format_,
+      .sink_format = target_format_,
+      .cue_at_sample = samples_written_,
   });
 }
 
-auto SampleConverter::handleContinueStream(size_t samples_available) -> void {
+auto SampleProcessor::handleContinueStream(size_t samples_available) -> void {
   // Loop until we finish reading all the bytes indicated. There might be
   // leftovers from each iteration, and from this process as a whole,
   // depending on the resampling stage.
@@ -182,7 +190,7 @@ auto SampleConverter::handleContinueStream(size_t samples_available) -> void {
   }
 }
 
-auto SampleConverter::handleSamples(cpp::span<sample::Sample> input) -> size_t {
+auto SampleProcessor::handleSamples(std::span<sample::Sample> input) -> size_t {
   if (source_format_ == target_format_) {
     // The happiest possible case: the input format matches the output
     // format already.
@@ -192,7 +200,7 @@ auto SampleConverter::handleSamples(cpp::span<sample::Sample> input) -> size_t {
 
   size_t samples_used = 0;
   while (samples_used < input.size()) {
-    cpp::span<sample::Sample> output_source;
+    std::span<sample::Sample> output_source;
     if (source_format_.sample_rate != target_format_.sample_rate) {
       if (resampler_ == nullptr) {
         ESP_LOGI(kTag, "creating new resampler for %lu -> %lu",
@@ -223,8 +231,8 @@ auto SampleConverter::handleSamples(cpp::span<sample::Sample> input) -> size_t {
   return samples_used;
 }
 
-auto SampleConverter::handleEndStream() -> void {
-  if (resampler_) {
+auto SampleProcessor::handleEndStream(bool clear_bufs) -> void {
+  if (resampler_ && !clear_bufs) {
     size_t read, written;
     std::tie(read, written) = resampler_->Process({}, resampled_buffer_, true);
 
@@ -233,33 +241,31 @@ auto SampleConverter::handleEndStream() -> void {
     }
   }
 
-  // Send a final update to finish off this stream's samples.
-  if (samples_sunk_ > 0) {
-    events::Audio().Dispatch(internal::StreamUpdate{
-        .samples_sunk = samples_sunk_,
-    });
-    samples_sunk_ = 0;
+  if (clear_bufs) {
+    assert(xStreamBufferReset(sink_));
+    samples_written_ = output_->samplesUsed();
   }
+
+  // FIXME: This discards any leftover samples, but there probably shouldn't be
+  // any leftover samples. Can this be an assert instead?
   leftover_bytes_ = 0;
 
-  events::Audio().Dispatch(internal::StreamEnded{});
+  events::Audio().Dispatch(internal::StreamEnded{
+      .cue_at_sample = samples_written_,
+  });
 }
 
-auto SampleConverter::sendToSink(cpp::span<sample::Sample> samples) -> void {
-  // Update the number of samples sunk so far *before* actually sinking them,
-  // since writing to the stream buffer will block when the buffer gets full.
-  samples_sunk_ += samples.size();
-  if (samples_sunk_ >=
-      target_format_.sample_rate * target_format_.num_channels) {
-    events::Audio().Dispatch(internal::StreamUpdate{
-        .samples_sunk = samples_sunk_,
-    });
-    samples_sunk_ = 0;
-  }
+auto SampleProcessor::sendToSink(std::span<sample::Sample> samples) -> void {
+  auto data = std::as_bytes(samples);
+  xStreamBufferSend(sink_, data.data(), data.size(), portMAX_DELAY);
 
-  xStreamBufferSend(sink_->stream(),
-                    reinterpret_cast<std::byte*>(samples.data()),
-                    samples.size_bytes(), portMAX_DELAY);
+  uint32_t samples_before_overflow =
+      std::numeric_limits<uint32_t>::max() - samples_written_;
+  if (samples_before_overflow < samples.size()) {
+    samples_written_ = samples.size() - samples_before_overflow;
+  } else {
+    samples_written_ += samples.size();
+  }
 }
 
 }  // namespace audio
diff --git a/src/audio/include/audio_converter.hpp b/src/tangara/audio/processor.hpp
index 232b5d8e..1bd6beff 100644
--- a/src/audio/include/audio_converter.hpp
+++ b/src/tangara/audio/processor.hpp
@@ -10,11 +10,11 @@
 #include <cstdint>
 #include <memory>
 
-#include "audio_events.hpp"
-#include "audio_sink.hpp"
-#include "audio_source.hpp"
+#include "audio/audio_events.hpp"
+#include "audio/audio_sink.hpp"
+#include "audio/audio_source.hpp"
+#include "audio/resample.hpp"
 #include "codec.hpp"
-#include "resample.hpp"
 #include "sample.hpp"
 
 namespace audio {
@@ -25,49 +25,52 @@ namespace audio {
  * format of the current output device. The resulting samples are forwarded
  * to the output device's sink stream.
  */
-class SampleConverter {
+class SampleProcessor {
  public:
-  SampleConverter();
-  ~SampleConverter();
+  SampleProcessor(StreamBufferHandle_t sink);
+  ~SampleProcessor();
 
   auto SetOutput(std::shared_ptr<IAudioOutput>) -> void;
 
   auto beginStream(std::shared_ptr<TrackInfo>) -> void;
-  auto continueStream(cpp::span<sample::Sample>) -> void;
-  auto endStream() -> void;
+  auto continueStream(std::span<sample::Sample>) -> void;
+  auto endStream(bool cancelled) -> void;
 
  private:
   auto Main() -> void;
 
   auto handleBeginStream(std::shared_ptr<TrackInfo>) -> void;
   auto handleContinueStream(size_t samples_available) -> void;
-  auto handleEndStream() -> void;
+  auto handleEndStream(bool cancel) -> void;
 
-  auto handleSamples(cpp::span<sample::Sample>) -> size_t;
+  auto handleSamples(std::span<sample::Sample>) -> size_t;
 
-  auto sendToSink(cpp::span<sample::Sample>) -> void;
+  auto sendToSink(std::span<sample::Sample>) -> void;
 
   struct Args {
     std::shared_ptr<TrackInfo>* track;
     size_t samples_available;
     bool is_end_of_stream;
+    bool clear_buffers;
   };
   QueueHandle_t commands_;
 
   std::unique_ptr<Resampler> resampler_;
 
   StreamBufferHandle_t source_;
-  cpp::span<sample::Sample> input_buffer_;
-  cpp::span<std::byte> input_buffer_as_bytes_;
+  StreamBufferHandle_t sink_;
 
-  cpp::span<sample::Sample> resampled_buffer_;
+  std::span<sample::Sample> input_buffer_;
+  std::span<std::byte> input_buffer_as_bytes_;
 
-  std::shared_ptr<IAudioOutput> sink_;
+  std::span<sample::Sample> resampled_buffer_;
+
+  std::shared_ptr<IAudioOutput> output_;
   IAudioOutput::Format source_format_;
   IAudioOutput::Format target_format_;
   size_t leftover_bytes_;
 
-  uint32_t samples_sunk_;
+  uint32_t samples_written_;
 };
 
 }  // namespace audio
diff --git a/src/audio/readahead_source.cpp b/src/tangara/audio/readahead_source.cpp
index fe7ac3bd..602ec0b1 100644
--- a/src/audio/readahead_source.cpp
+++ b/src/tangara/audio/readahead_source.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "readahead_source.hpp"
+#include "audio/readahead_source.hpp"
 
 #include <cstddef>
 #include <cstdint>
@@ -14,10 +14,10 @@
 #include "esp_log.h"
 #include "ff.h"
 
-#include "audio_source.hpp"
+#include "audio/audio_source.hpp"
 #include "codec.hpp"
+#include "drivers/spi.hpp"
 #include "freertos/portmacro.h"
-#include "spi.hpp"
 #include "tasks.hpp"
 #include "types.hpp"
 
@@ -41,7 +41,7 @@ ReadaheadSource::~ReadaheadSource() {
   vStreamBufferDeleteWithCaps(buffer_);
 }
 
-auto ReadaheadSource::Read(cpp::span<std::byte> dest) -> ssize_t {
+auto ReadaheadSource::Read(std::span<std::byte> dest) -> ssize_t {
   size_t bytes_written = 0;
   // Fill the destination from our buffer, until either the buffer is drained
   // or the destination is full.
diff --git a/src/audio/include/readahead_source.hpp b/src/tangara/audio/readahead_source.hpp
index 3e18a989..bbaf9f75 100644
--- a/src/audio/include/readahead_source.hpp
+++ b/src/tangara/audio/readahead_source.hpp
@@ -15,7 +15,7 @@
 #include "ff.h"
 #include "freertos/stream_buffer.h"
 
-#include "audio_source.hpp"
+#include "audio/audio_source.hpp"
 #include "codec.hpp"
 #include "tasks.hpp"
 
@@ -30,7 +30,7 @@ class ReadaheadSource : public codecs::IStream {
   ReadaheadSource(tasks::WorkerPool&, std::unique_ptr<codecs::IStream>);
   ~ReadaheadSource();
 
-  auto Read(cpp::span<std::byte> dest) -> ssize_t override;
+  auto Read(std::span<std::byte> dest) -> ssize_t override;
 
   auto CanSeek() -> bool override;
 
diff --git a/src/audio/resample.cpp b/src/tangara/audio/resample.cpp
index a3a34ee7..143ce230 100644
--- a/src/audio/resample.cpp
+++ b/src/tangara/audio/resample.cpp
@@ -3,7 +3,7 @@
  *
  * SPDX-License-Identifier: GPL-3.0-only
  */
-#include "resample.hpp"
+#include "audio/resample.hpp"
 
 #include <algorithm>
 #include <cmath>
@@ -38,8 +38,8 @@ Resampler::~Resampler() {
   speex_resampler_destroy(resampler_);
 }
 
-auto Resampler::Process(cpp::span<sample::Sample> input,
-                        cpp::span<sample::Sample> output,
+auto Resampler::Process(std::span<sample::Sample> input,
+                        std::span<sample::Sample> output,
                         bool end_of_data) -> std::pair<size_t, size_t> {
   uint32_t samples_used = input.size() / num_channels_;
   uint32_t samples_produced = output.size() / num_channels_;
diff --git a/src/audio/include/resample.hpp b/src/tangara/audio/resample.hpp
index a9464cb1..4d48d47f 100644
--- a/src/audio/include/resample.hpp
+++ b/src/tangara/audio/resample.hpp
@@ -7,9 +7,9 @@
 #pragma once
 
 #include <cstdint>
+#include <span>
 #include <vector>
 
-#include "span.hpp"
 #include "speex/speex_resampler.h"
 
 #include "sample.hpp"
@@ -24,8 +24,8 @@ class Resampler {
 
   ~Resampler();
 
-  auto Process(cpp::span<sample::Sample> input,
-               cpp::span<sample::Sample> output,
+  auto Process(std::span<sample::Sample> input,
+               std::span<sample::Sample> output,
                bool end_of_data) -> std::pair<size_t, size_t>;
 
  private:
@@ -34,4 +34,4 @@ class Resampler {
   uint8_t num_channels_;
 };
 
-}  // namespace audio
\ No newline at end of file
+}  // namespace audio
diff --git a/src/tangara/audio/stream_cues.cpp b/src/tangara/audio/stream_cues.cpp
new file mode 100644
index 00000000..7a6a1426
--- /dev/null
+++ b/src/tangara/audio/stream_cues.cpp
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2024 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "audio/stream_cues.hpp"
+
+#include <cstdint>
+#include <memory>
+
+namespace audio {
+
+StreamCues::StreamCues() : now_(0) {}
+
+auto StreamCues::update(uint32_t sample) -> void {
+  if (sample < now_) {
+    // The current time must have overflowed. Deal with any cues between now_
+    // and UINT32_MAX, then proceed as normal.
+    while (!upcoming_.empty() && upcoming_.front().start_at > now_) {
+      current_ = upcoming_.front();
+      upcoming_.pop_front();
+    }
+  }
+  now_ = sample;
+
+  while (!upcoming_.empty() && upcoming_.front().start_at <= now_) {
+    current_ = upcoming_.front();
+    upcoming_.pop_front();
+  }
+}
+
+auto StreamCues::addCue(std::shared_ptr<TrackInfo> track, uint32_t sample)
+    -> void {
+  if (sample == now_) {
+    current_ = {track, now_};
+  } else {
+    upcoming_.push_back(Cue{
+        .track = track,
+        .start_at = sample,
+    });
+  }
+}
+
+auto StreamCues::current() -> std::pair<std::shared_ptr<TrackInfo>, uint32_t> {
+  if (!current_) {
+    return {};
+  }
+
+  uint32_t duration;
+  if (now_ < current_->start_at) {
+    // now_ overflowed since this track started.
+    duration = now_ + (UINT32_MAX - current_->start_at);
+  } else {
+    duration = now_ - current_->start_at;
+  }
+
+  return {current_->track, duration};
+}
+
+auto StreamCues::hasStream() -> bool {
+  return current_ || !upcoming_.empty();
+}
+
+}  // namespace audio
diff --git a/src/tangara/audio/stream_cues.hpp b/src/tangara/audio/stream_cues.hpp
new file mode 100644
index 00000000..cd0782b0
--- /dev/null
+++ b/src/tangara/audio/stream_cues.hpp
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2024 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <cstdint>
+#include <deque>
+#include <memory>
+
+#include "audio/audio_events.hpp"
+
+namespace audio {
+
+/*
+ * Utility for tracking which track is currently being played (and how long it
+ * has been playing for) based on counting samples that are put into and taken
+ * out of the audio processor's output buffer.
+ */
+class StreamCues {
+ public:
+  StreamCues();
+
+  /* Updates the current track given the new most recently played sample. */
+  auto update(uint32_t sample) -> void;
+
+  /* Returns the current track, and how long it has been playing for. */
+  auto current() -> std::pair<std::shared_ptr<TrackInfo>, uint32_t>;
+
+  auto hasStream() -> bool;
+
+  auto addCue(std::shared_ptr<TrackInfo>, uint32_t start_at) -> void;
+
+ private:
+  uint32_t now_;
+
+  struct Cue {
+    std::shared_ptr<TrackInfo> track;
+    uint32_t start_at;
+  };
+
+  std::optional<Cue> current_;
+  std::deque<Cue> upcoming_;
+};
+
+}  // namespace audio
diff --git a/src/audio/test/CMakeLists.txt b/src/tangara/audio/test/CMakeLists.txt
index 4d580b1c..4d580b1c 100644
--- a/src/audio/test/CMakeLists.txt
+++ b/src/tangara/audio/test/CMakeLists.txt
diff --git a/src/audio/track_queue.cpp b/src/tangara/audio/track_queue.cpp
index dbe283c4..603b0de1 100644
--- a/src/audio/track_queue.cpp
+++ b/src/tangara/audio/track_queue.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "track_queue.hpp"
+#include "audio/track_queue.hpp"
 #include <stdint.h>
 
 #include <algorithm>
@@ -18,16 +18,16 @@
 #include "MillerShuffle.h"
 #include "esp_random.h"
 
-#include "audio_events.hpp"
-#include "audio_fsm.hpp"
+#include "audio/audio_events.hpp"
+#include "audio/audio_fsm.hpp"
 #include "cppbor.h"
 #include "cppbor_parse.h"
-#include "database.hpp"
-#include "event_queue.hpp"
+#include "database/database.hpp"
+#include "database/track.hpp"
+#include "events/event_queue.hpp"
 #include "memory_resource.hpp"
 #include "tasks.hpp"
-#include "track.hpp"
-#include "ui_fsm.hpp"
+#include "ui/ui_fsm.hpp"
 
 namespace audio {
 
diff --git a/src/audio/include/track_queue.hpp b/src/tangara/audio/track_queue.hpp
index 5b7c9448..427d5f75 100644
--- a/src/audio/include/track_queue.hpp
+++ b/src/tangara/audio/track_queue.hpp
@@ -12,11 +12,11 @@
 #include <shared_mutex>
 #include <vector>
 
-#include "audio_events.hpp"
+#include "audio/audio_events.hpp"
 #include "cppbor_parse.h"
-#include "database.hpp"
+#include "database/database.hpp"
+#include "database/track.hpp"
 #include "tasks.hpp"
-#include "track.hpp"
 
 namespace audio {
 
diff --git a/src/battery/battery.cpp b/src/tangara/battery/battery.cpp
index debef9e6..2d2fff56 100644
--- a/src/battery/battery.cpp
+++ b/src/tangara/battery/battery.cpp
@@ -4,15 +4,15 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "battery.hpp"
+#include "battery/battery.hpp"
 
 #include <cstdint>
 
-#include "adc.hpp"
-#include "event_queue.hpp"
+#include "drivers/adc.hpp"
+#include "drivers/samd.hpp"
+#include "events/event_queue.hpp"
 #include "freertos/portmacro.h"
-#include "samd.hpp"
-#include "system_events.hpp"
+#include "system_fsm/system_events.hpp"
 
 namespace battery {
 
diff --git a/src/battery/include/battery.hpp b/src/tangara/battery/battery.hpp
index 314cd373..80b0f2d2 100644
--- a/src/battery/include/battery.hpp
+++ b/src/tangara/battery/battery.hpp
@@ -11,8 +11,8 @@
 #include "freertos/FreeRTOS.h"
 #include "freertos/timers.h"
 
-#include "adc.hpp"
-#include "samd.hpp"
+#include "drivers/adc.hpp"
+#include "drivers/samd.hpp"
 
 namespace battery {
 
diff --git a/src/database/database.cpp b/src/tangara/database/database.cpp
index 48fb0c63..4064c3ed 100644
--- a/src/database/database.cpp
+++ b/src/tangara/database/database.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "database.hpp"
+#include "database/database.hpp"
 
 #include <stdint.h>
 #include <sys/_stdint.h>
@@ -23,10 +23,10 @@
 #include "collation.hpp"
 #include "cppbor.h"
 #include "cppbor_parse.h"
+#include "database/index.hpp"
 #include "esp_log.h"
 #include "ff.h"
 #include "freertos/projdefs.h"
-#include "index.hpp"
 #include "komihash.h"
 #include "leveldb/cache.h"
 #include "leveldb/db.h"
@@ -36,17 +36,17 @@
 #include "leveldb/status.h"
 #include "leveldb/write_batch.h"
 
-#include "db_events.hpp"
-#include "env_esp.hpp"
-#include "event_queue.hpp"
-#include "file_gatherer.hpp"
+#include "database/db_events.hpp"
+#include "database/env_esp.hpp"
+#include "database/file_gatherer.hpp"
+#include "database/records.hpp"
+#include "database/tag_parser.hpp"
+#include "database/track.hpp"
+#include "drivers/spi.hpp"
+#include "events/event_queue.hpp"
 #include "memory_resource.hpp"
-#include "records.hpp"
 #include "result.hpp"
-#include "spi.hpp"
-#include "tag_parser.hpp"
 #include "tasks.hpp"
-#include "track.hpp"
 
 namespace database {
 
@@ -63,8 +63,8 @@ static const char kKeyTrackId[] = "next_track_id";
 
 static std::atomic<bool> sIsDbOpen(false);
 
-static auto CreateNewDatabase(leveldb::Options& options, locale::ICollator& col)
-    -> leveldb::DB* {
+static auto CreateNewDatabase(leveldb::Options& options,
+                              locale::ICollator& col) -> leveldb::DB* {
   Database::Destroy();
   leveldb::DB* db;
   options.create_if_missing = true;
diff --git a/src/database/include/database.hpp b/src/tangara/database/database.hpp
index 35b76a13..d2de7c72 100644
--- a/src/database/include/database.hpp
+++ b/src/tangara/database/database.hpp
@@ -19,19 +19,19 @@
 
 #include "collation.hpp"
 #include "cppbor.h"
-#include "file_gatherer.hpp"
-#include "index.hpp"
+#include "database/file_gatherer.hpp"
+#include "database/index.hpp"
+#include "database/records.hpp"
+#include "database/tag_parser.hpp"
+#include "database/track.hpp"
 #include "leveldb/cache.h"
 #include "leveldb/db.h"
 #include "leveldb/iterator.h"
 #include "leveldb/options.h"
 #include "leveldb/slice.h"
 #include "memory_resource.hpp"
-#include "records.hpp"
 #include "result.hpp"
-#include "tag_parser.hpp"
 #include "tasks.hpp"
-#include "track.hpp"
 
 namespace database {
 
diff --git a/src/database/include/db_events.hpp b/src/tangara/database/db_events.hpp
index a1aefc27..a1aefc27 100644
--- a/src/database/include/db_events.hpp
+++ b/src/tangara/database/db_events.hpp
diff --git a/src/database/env_esp.cpp b/src/tangara/database/env_esp.cpp
index f7a5637a..86a30613 100644
--- a/src/database/env_esp.cpp
+++ b/src/tangara/database/env_esp.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "env_esp.hpp"
+#include "database/env_esp.hpp"
 
 #include <atomic>
 #include <cerrno>
@@ -36,12 +36,12 @@
 #include "leveldb/slice.h"
 #include "leveldb/status.h"
 
-#include "spi.hpp"
+#include "drivers/spi.hpp"
 #include "tasks.hpp"
 
 namespace leveldb {
 
-tasks::WorkerPool *sBackgroundThread = nullptr;
+tasks::WorkerPool* sBackgroundThread = nullptr;
 
 std::string ErrToStr(FRESULT err) {
   switch (err) {
diff --git a/src/database/include/env_esp.hpp b/src/tangara/database/env_esp.hpp
index 472a72a6..472a72a6 100644
--- a/src/database/include/env_esp.hpp
+++ b/src/tangara/database/env_esp.hpp
diff --git a/src/database/file_gatherer.cpp b/src/tangara/database/file_gatherer.cpp
index b7b7271e..75a1af27 100644
--- a/src/database/file_gatherer.cpp
+++ b/src/tangara/database/file_gatherer.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "file_gatherer.hpp"
+#include "database/file_gatherer.hpp"
 
 #include <deque>
 #include <functional>
@@ -13,8 +13,8 @@
 
 #include "ff.h"
 
+#include "drivers/spi.hpp"
 #include "memory_resource.hpp"
-#include "spi.hpp"
 
 namespace database {
 
diff --git a/src/database/include/file_gatherer.hpp b/src/tangara/database/file_gatherer.hpp
index 685bdb2c..38558b9e 100644
--- a/src/database/include/file_gatherer.hpp
+++ b/src/tangara/database/file_gatherer.hpp
@@ -17,20 +17,18 @@ namespace database {
 
 class IFileGatherer {
  public:
-  virtual ~IFileGatherer(){};
+  virtual ~IFileGatherer() {};
 
   virtual auto FindFiles(
       const std::string& root,
-      std::function<void(std::string_view, const FILINFO&)> cb)
-      -> void = 0;
+      std::function<void(std::string_view, const FILINFO&)> cb) -> void = 0;
 };
 
 class FileGathererImpl : public IFileGatherer {
  public:
-  virtual auto FindFiles(
-      const std::string& root,
-      std::function<void(std::string_view, const FILINFO&)> cb)
-      -> void override;
+  virtual auto FindFiles(const std::string& root,
+                         std::function<void(std::string_view, const FILINFO&)>
+                             cb) -> void override;
 };
 
 }  // namespace database
diff --git a/src/database/include/future_fetcher.hpp b/src/tangara/database/future_fetcher.hpp
index e8ce9729..a27101f1 100644
--- a/src/database/include/future_fetcher.hpp
+++ b/src/tangara/database/future_fetcher.hpp
@@ -9,7 +9,7 @@
 #include <memory>
 #include <utility>
 
-#include "database.hpp"
+#include "database/database.hpp"
 
 namespace database {
 
diff --git a/src/database/index.cpp b/src/tangara/database/index.cpp
index 857fbcc5..93a2b1c2 100644
--- a/src/database/index.cpp
+++ b/src/tangara/database/index.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "index.hpp"
+#include "database/index.hpp"
 #include <sys/_stdint.h>
 
 #include <cstdint>
@@ -21,8 +21,8 @@
 #include "komihash.h"
 #include "leveldb/write_batch.h"
 
-#include "records.hpp"
-#include "track.hpp"
+#include "database/records.hpp"
+#include "database/track.hpp"
 
 namespace database {
 
@@ -61,11 +61,11 @@ class Indexer {
 
  private:
   auto handleLevel(const IndexKey::Header& header,
-                   cpp::span<const Tag> components) -> void;
+                   std::span<const Tag> components) -> void;
 
   auto handleItem(const IndexKey::Header& header,
                   std::variant<std::pmr::string, uint32_t> item,
-                  cpp::span<const Tag> components) -> void;
+                  std::span<const Tag> components) -> void;
 
   auto missing_value(Tag tag) -> TagValue {
     switch (tag) {
@@ -111,7 +111,7 @@ auto Indexer::index() -> std::vector<std::pair<IndexKey, std::string>> {
 }
 
 auto Indexer::handleLevel(const IndexKey::Header& header,
-                          cpp::span<const Tag> components) -> void {
+                          std::span<const Tag> components) -> void {
   Tag component = components.front();
   TagValue value = track_.tags().get(component);
   if (std::holds_alternative<std::monostate>(value)) {
@@ -129,7 +129,7 @@ auto Indexer::handleLevel(const IndexKey::Header& header,
         } else if constexpr (std::is_same_v<T, uint32_t>) {
           handleItem(header, arg, components);
         } else if constexpr (std::is_same_v<
-                                 T, cpp::span<const std::pmr::string>>) {
+                                 T, std::span<const std::pmr::string>>) {
           for (const auto& i : arg) {
             handleItem(header, i, components);
           }
@@ -140,7 +140,7 @@ auto Indexer::handleLevel(const IndexKey::Header& header,
 
 auto Indexer::handleItem(const IndexKey::Header& header,
                          std::variant<std::pmr::string, uint32_t> item,
-                         cpp::span<const Tag> components) -> void {
+                         std::span<const Tag> components) -> void {
   IndexKey key{
       .header = header,
       .item = {},
@@ -183,8 +183,9 @@ auto Indexer::handleItem(const IndexKey::Header& header,
   }
 }
 
-auto Index(locale::ICollator& c, const IndexInfo& i, const Track& t)
-    -> std::vector<std::pair<IndexKey, std::string>> {
+auto Index(locale::ICollator& c,
+           const IndexInfo& i,
+           const Track& t) -> std::vector<std::pair<IndexKey, std::string>> {
   Indexer indexer{c, t, i};
   return indexer.index();
 }
diff --git a/src/database/include/index.hpp b/src/tangara/database/index.hpp
index 45dae464..8f78439b 100644
--- a/src/database/include/index.hpp
+++ b/src/tangara/database/index.hpp
@@ -17,9 +17,9 @@
 #include "leveldb/db.h"
 #include "leveldb/slice.h"
 
+#include "database/track.hpp"
 #include "leveldb/write_batch.h"
 #include "memory_resource.hpp"
-#include "track.hpp"
 
 namespace database {
 
@@ -61,8 +61,9 @@ struct IndexKey {
   std::optional<TrackId> track;
 };
 
-auto Index(locale::ICollator&, const IndexInfo&, const Track&)
-    -> std::vector<std::pair<IndexKey, std::string>>;
+auto Index(locale::ICollator&,
+           const IndexInfo&,
+           const Track&) -> std::vector<std::pair<IndexKey, std::string>>;
 
 auto ExpandHeader(const IndexKey::Header&,
                   const std::optional<std::pmr::string>&) -> IndexKey::Header;
diff --git a/src/database/records.cpp b/src/tangara/database/records.cpp
index a1efb568..88ddbd91 100644
--- a/src/database/records.cpp
+++ b/src/tangara/database/records.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "records.hpp"
+#include "database/records.hpp"
 
 #include <stdint.h>
 #include <sys/_stdint.h>
@@ -21,10 +21,10 @@
 #include "cppbor_parse.h"
 #include "esp_log.h"
 
-#include "index.hpp"
+#include "database/index.hpp"
+#include "database/track.hpp"
 #include "komihash.h"
 #include "memory_resource.hpp"
-#include "track.hpp"
 
 // As LevelDB is a key-value store, each record in the database consists of a
 // key and an optional value.
@@ -248,7 +248,7 @@ auto TrackIdToBytes(TrackId id) -> std::string {
   return cppbor::Uint{id}.toString();
 }
 
-auto BytesToTrackId(cpp::span<const char> bytes) -> std::optional<TrackId> {
+auto BytesToTrackId(std::span<const char> bytes) -> std::optional<TrackId> {
   auto [res, unused, err] = cppbor::parse(
       reinterpret_cast<const uint8_t*>(bytes.data()), bytes.size());
   if (!res || res->type() != cppbor::UINT) {
diff --git a/src/database/include/records.hpp b/src/tangara/database/records.hpp
index 87034059..db18fe2f 100644
--- a/src/database/include/records.hpp
+++ b/src/tangara/database/records.hpp
@@ -15,9 +15,9 @@
 #include "leveldb/db.h"
 #include "leveldb/slice.h"
 
-#include "index.hpp"
+#include "database/index.hpp"
+#include "database/track.hpp"
 #include "memory_resource.hpp"
-#include "track.hpp"
 
 namespace database {
 
@@ -80,6 +80,6 @@ auto TrackIdToBytes(TrackId id) -> std::string;
  * Converts a track id encoded via TrackIdToBytes back into a TrackId. May
  * return nullopt if parsing fails.
  */
-auto BytesToTrackId(cpp::span<const char> bytes) -> std::optional<TrackId>;
+auto BytesToTrackId(std::span<const char> bytes) -> std::optional<TrackId>;
 
 }  // namespace database
diff --git a/src/database/tag_parser.cpp b/src/tangara/database/tag_parser.cpp
index cbcbdcb5..2df2d90f 100644
--- a/src/database/tag_parser.cpp
+++ b/src/tangara/database/tag_parser.cpp
@@ -4,16 +4,16 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "tag_parser.hpp"
+#include "database/tag_parser.hpp"
 
 #include <cstdint>
 #include <cstdlib>
 #include <iomanip>
 #include <mutex>
 
+#include "drivers/spi.hpp"
 #include "esp_log.h"
 #include "ff.h"
-#include "spi.hpp"
 #include "tags.h"
 
 #include "memory_resource.hpp"
diff --git a/src/database/include/tag_parser.hpp b/src/tangara/database/tag_parser.hpp
index 966258b5..ccbc0ea9 100644
--- a/src/database/include/tag_parser.hpp
+++ b/src/tangara/database/tag_parser.hpp
@@ -8,8 +8,8 @@
 
 #include <string>
 
+#include "database/track.hpp"
 #include "lru_cache.hpp"
-#include "track.hpp"
 
 namespace database {
 
diff --git a/src/database/test/CMakeLists.txt b/src/tangara/database/test/CMakeLists.txt
index a9f2cedb..a9f2cedb 100644
--- a/src/database/test/CMakeLists.txt
+++ b/src/tangara/database/test/CMakeLists.txt
diff --git a/src/database/test/test_database.cpp b/src/tangara/database/test/test_database.cpp
index 6aec9bfb..09e19a43 100644
--- a/src/database/test/test_database.cpp
+++ b/src/tangara/database/test/test_database.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "database.hpp"
+#include "database/database.hpp"
 
 #include <stdint.h>
 #include <iomanip>
@@ -13,14 +13,14 @@
 #include <string>
 
 #include "catch2/catch.hpp"
+#include "database/file_gatherer.hpp"
+#include "database/tag_parser.hpp"
+#include "database/track.hpp"
 #include "driver_cache.hpp"
 #include "esp_log.h"
-#include "file_gatherer.hpp"
 #include "i2c_fixture.hpp"
 #include "leveldb/db.h"
 #include "spi_fixture.hpp"
-#include "tag_parser.hpp"
-#include "track.hpp"
 
 namespace database {
 
@@ -28,8 +28,8 @@ class TestBackends : public IFileGatherer, public ITagParser {
  public:
   std::map<std::pmr::string, TrackTags> tracks;
 
-  auto MakeTrack(const std::pmr::string& path, const std::pmr::string& title)
-      -> void {
+  auto MakeTrack(const std::pmr::string& path,
+                 const std::pmr::string& title) -> void {
     TrackTags tags;
     tags.encoding = Encoding::kMp3;
     tags.title = title;
@@ -44,8 +44,8 @@ class TestBackends : public IFileGatherer, public ITagParser {
     }
   }
 
-  auto ReadAndParseTags(const std::pmr::string& path, TrackTags* out)
-      -> bool override {
+  auto ReadAndParseTags(const std::pmr::string& path,
+                        TrackTags* out) -> bool override {
     if (tracks.contains(path)) {
       *out = tracks.at(path);
       return true;
diff --git a/src/database/test/test_records.cpp b/src/tangara/database/test/test_records.cpp
index 2f59489c..f8eb980f 100644
--- a/src/database/test/test_records.cpp
+++ b/src/tangara/database/test/test_records.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "records.hpp"
+#include "database/records.hpp"
 
 #include <stdint.h>
 #include <iomanip>
diff --git a/src/database/track.cpp b/src/tangara/database/track.cpp
index a2bd05d3..5bf8c3e2 100644
--- a/src/database/track.cpp
+++ b/src/tangara/database/track.cpp
@@ -4,11 +4,12 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "track.hpp"
+#include "database/track.hpp"
 
 #include <iomanip>
 #include <iostream>
 #include <memory_resource>
+#include <span>
 #include <sstream>
 #include <string>
 
@@ -16,7 +17,6 @@
 #include "komihash.h"
 
 #include "memory_resource.hpp"
-#include "span.hpp"
 
 namespace database {
 
@@ -55,7 +55,7 @@ auto tagHash(const TagValue& t) -> uint64_t {
         } else if constexpr (std::is_same_v<T, uint32_t>) {
           return komihash(&arg, sizeof(arg), 0);
         } else if constexpr (std::is_same_v<
-                                 T, cpp::span<const std::pmr::string>>) {
+                                 T, std::span<const std::pmr::string>>) {
           komihash_stream_t hash;
           komihash_stream_init(&hash, 0);
           for (const auto& i : arg) {
@@ -79,7 +79,7 @@ auto tagToString(const TagValue& val) -> std::string {
         } else if constexpr (std::is_same_v<T, uint32_t>) {
           return std::to_string(arg);
         } else if constexpr (std::is_same_v<
-                                 T, cpp::span<const std::pmr::string>>) {
+                                 T, std::span<const std::pmr::string>>) {
           std::ostringstream builder{};
           for (const auto& str : arg) {
             builder << std::string{str.data(), str.size()} << ",";
@@ -225,7 +225,7 @@ auto TrackTags::albumOrder() const -> uint32_t {
   return (disc_.value_or(0) << 16) | track_.value_or(0);
 }
 
-auto TrackTags::genres() const -> cpp::span<const std::pmr::string> {
+auto TrackTags::genres() const -> std::span<const std::pmr::string> {
   return genres_;
 }
 
diff --git a/src/database/include/track.hpp b/src/tangara/database/track.hpp
index 76b1c56e..b097ab52 100644
--- a/src/database/include/track.hpp
+++ b/src/tangara/database/track.hpp
@@ -6,12 +6,12 @@
 
 #pragma once
 
-#include <stdint.h>
-#include <sys/_stdint.h>
+#include <cstdint>
 
 #include <map>
 #include <memory>
 #include <optional>
+#include <span>
 #include <string>
 #include <unordered_map>
 #include <utility>
@@ -19,7 +19,6 @@
 
 #include "leveldb/db.h"
 #include "memory_resource.hpp"
-#include "span.hpp"
 
 namespace database {
 
@@ -62,7 +61,7 @@ enum class Tag {
 using TagValue = std::variant<std::monostate,
                               std::pmr::string,
                               uint32_t,
-                              cpp::span<const std::pmr::string>>;
+                              std::span<const std::pmr::string>>;
 
 auto tagName(Tag) -> std::string;
 auto tagHash(const TagValue&) -> uint64_t;
@@ -112,7 +111,7 @@ class TrackTags {
 
   auto albumOrder() const -> uint32_t;
 
-  auto genres() const -> cpp::span<const std::pmr::string>;
+  auto genres() const -> std::span<const std::pmr::string>;
   auto genres(const std::string_view) -> void;
 
   /*
diff --git a/src/dev_console/console.cpp b/src/tangara/dev_console/console.cpp
index f2b1efea..cee68b49 100644
--- a/src/dev_console/console.cpp
+++ b/src/tangara/dev_console/console.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "console.hpp"
+#include "dev_console/console.hpp"
 #include <stdio.h>
 #include <string.h>
 
diff --git a/src/dev_console/include/console.hpp b/src/tangara/dev_console/console.hpp
index fedf3632..fedf3632 100644
--- a/src/dev_console/include/console.hpp
+++ b/src/tangara/dev_console/console.hpp
diff --git a/src/events/event_queue.cpp b/src/tangara/events/event_queue.cpp
index d3a62ef6..e4751398 100644
--- a/src/events/event_queue.cpp
+++ b/src/tangara/events/event_queue.cpp
@@ -4,14 +4,15 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "event_queue.hpp"
+#include "events/event_queue.hpp"
 
-#include "audio_fsm.hpp"
 #include "freertos/FreeRTOS.h"
 #include "freertos/portmacro.h"
 #include "freertos/queue.h"
-#include "system_fsm.hpp"
-#include "ui_fsm.hpp"
+
+#include "audio/audio_fsm.hpp"
+#include "system_fsm/system_fsm.hpp"
+#include "ui/ui_fsm.hpp"
 
 namespace events {
 
diff --git a/src/events/include/event_queue.hpp b/src/tangara/events/event_queue.hpp
index 78b21d53..aa7f472d 100644
--- a/src/events/include/event_queue.hpp
+++ b/src/tangara/events/event_queue.hpp
@@ -11,14 +11,14 @@
 #include <queue>
 #include <type_traits>
 
-#include "audio_fsm.hpp"
+#include "audio/audio_fsm.hpp"
 #include "freertos/FreeRTOS.h"
 #include "freertos/portmacro.h"
 #include "freertos/queue.h"
-#include "system_fsm.hpp"
+#include "system_fsm/system_fsm.hpp"
 #include "tinyfsm.hpp"
 
-#include "ui_fsm.hpp"
+#include "ui/ui_fsm.hpp"
 
 namespace events {
 
diff --git a/src/input/device_factory.cpp b/src/tangara/input/device_factory.cpp
index 65f4d785..8e1c5155 100644
--- a/src/input/device_factory.cpp
+++ b/src/tangara/input/device_factory.cpp
@@ -4,16 +4,16 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "device_factory.hpp"
+#include "input/device_factory.hpp"
 
 #include <memory>
 
-#include "feedback_haptics.hpp"
-#include "input_device.hpp"
-#include "input_nav_buttons.hpp"
-#include "input_touch_dpad.hpp"
-#include "input_touch_wheel.hpp"
-#include "input_volume_buttons.hpp"
+#include "input/feedback_haptics.hpp"
+#include "input/input_device.hpp"
+#include "input/input_nav_buttons.hpp"
+#include "input/input_touch_dpad.hpp"
+#include "input/input_touch_wheel.hpp"
+#include "input/input_volume_buttons.hpp"
 
 namespace input {
 
diff --git a/src/input/include/device_factory.hpp b/src/tangara/input/device_factory.hpp
index dd9c7133..5044d025 100644
--- a/src/input/include/device_factory.hpp
+++ b/src/tangara/input/device_factory.hpp
@@ -9,11 +9,11 @@
 #include <cstdint>
 #include <memory>
 
-#include "feedback_device.hpp"
-#include "input_device.hpp"
-#include "input_touch_wheel.hpp"
-#include "nvs.hpp"
-#include "service_locator.hpp"
+#include "input/feedback_device.hpp"
+#include "input/input_device.hpp"
+#include "input/input_touch_wheel.hpp"
+#include "drivers/nvs.hpp"
+#include "system_fsm/service_locator.hpp"
 
 namespace input {
 
diff --git a/src/input/include/feedback_device.hpp b/src/tangara/input/feedback_device.hpp
index 4faeeafd..4faeeafd 100644
--- a/src/input/include/feedback_device.hpp
+++ b/src/tangara/input/feedback_device.hpp
diff --git a/src/input/feedback_haptics.cpp b/src/tangara/input/feedback_haptics.cpp
index 5e83d0d6..e690eb9f 100644
--- a/src/input/feedback_haptics.cpp
+++ b/src/tangara/input/feedback_haptics.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "feedback_haptics.hpp"
+#include "input/feedback_haptics.hpp"
 
 #include <cstdint>
 
@@ -13,7 +13,7 @@
 #include "core/lv_event.h"
 #include "esp_log.h"
 
-#include "haptics.hpp"
+#include "drivers/haptics.hpp"
 
 namespace input {
 
diff --git a/src/input/include/feedback_haptics.hpp b/src/tangara/input/feedback_haptics.hpp
index a307a429..bde5f345 100644
--- a/src/input/include/feedback_haptics.hpp
+++ b/src/tangara/input/feedback_haptics.hpp
@@ -8,8 +8,8 @@
 
 #include <cstdint>
 
-#include "feedback_device.hpp"
-#include "haptics.hpp"
+#include "drivers/haptics.hpp"
+#include "input/feedback_device.hpp"
 
 namespace input {
 
diff --git a/src/input/include/input_device.hpp b/src/tangara/input/input_device.hpp
index 59456351..e3d17c6c 100644
--- a/src/input/include/input_device.hpp
+++ b/src/tangara/input/input_device.hpp
@@ -11,8 +11,8 @@
 #include <vector>
 
 #include "hal/lv_hal_indev.h"
-#include "input_hook.hpp"
-#include "property.hpp"
+#include "input/input_hook.hpp"
+#include "lua/property.hpp"
 
 namespace input {
 
@@ -29,7 +29,9 @@ class IInputDevice {
   virtual auto read(lv_indev_data_t* data) -> void = 0;
 
   virtual auto name() -> std::string = 0;
-  virtual auto hooks() -> std::vector<TriggerHooks> { return {}; }
+  virtual auto triggers() -> std::vector<std::reference_wrapper<TriggerHooks>> {
+    return {};
+  }
 };
 
 }  // namespace input
diff --git a/src/input/input_hook.cpp b/src/tangara/input/input_hook.cpp
index 1bb92196..95ff8f2c 100644
--- a/src/input/input_hook.cpp
+++ b/src/tangara/input/input_hook.cpp
@@ -4,13 +4,15 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "input_hook.hpp"
+#include "input/input_hook.hpp"
 
 #include <functional>
 #include <optional>
+
 #include "hal/lv_hal_indev.h"
-#include "input_trigger.hpp"
-#include "lua.h"
+#include "lua.hpp"
+
+#include "input/input_trigger.hpp"
 
 namespace input {
 
@@ -39,10 +41,12 @@ auto Hook::callback() -> std::optional<HookCallback> {
 
 TriggerHooks::TriggerHooks(std::string name,
                            std::optional<HookCallback> click,
+                           std::optional<HookCallback> double_click,
                            std::optional<HookCallback> long_press,
                            std::optional<HookCallback> repeat)
     : name_(name),
       click_("click", click),
+      double_click_("double_click", double_click),
       long_press_("long_press", long_press),
       repeat_("repeat", repeat) {}
 
@@ -51,6 +55,9 @@ auto TriggerHooks::update(bool pressed, lv_indev_data_t* d) -> void {
     case Trigger::State::kClick:
       click_.invoke(d);
       break;
+    case Trigger::State::kDoubleClick:
+      double_click_.invoke(d);
+      break;
     case Trigger::State::kLongPress:
       long_press_.invoke(d);
       break;
@@ -85,23 +92,12 @@ auto TriggerHooks::name() const -> const std::string& {
   return name_;
 }
 
-auto TriggerHooks::pushHooks(lua_State* L) -> void {
-  lua_newtable(L);
-
-  auto add_trigger = [&](Hook& h) {
-    lua_pushlstring(L, h.name().data(), h.name().size());
-    auto cb = h.callback();
-    if (cb) {
-      lua_pushlstring(L, cb->name.data(), cb->name.size());
-    } else {
-      lua_pushnil(L);
-    }
-    lua_rawset(L, -3);
-  };
-
-  add_trigger(click_);
-  add_trigger(long_press_);
-  add_trigger(repeat_);
+auto TriggerHooks::hooks() -> std::vector<std::reference_wrapper<Hook>> {
+  return {click_, long_press_, repeat_};
+}
+
+auto TriggerHooks::cancel() -> void {
+  trigger_.cancel();
 }
 
 }  // namespace input
diff --git a/src/input/include/input_hook.hpp b/src/tangara/input/input_hook.hpp
index 81eb80d9..06fcb037 100644
--- a/src/input/include/input_hook.hpp
+++ b/src/tangara/input/input_hook.hpp
@@ -13,7 +13,7 @@
 #include "hal/lv_hal_indev.h"
 #include "lua.hpp"
 
-#include "input_trigger.hpp"
+#include "input/input_trigger.hpp"
 
 namespace input {
 
@@ -32,6 +32,10 @@ class Hook {
   auto name() const -> const std::string& { return name_; }
   auto callback() -> std::optional<HookCallback>;
 
+  // Not copyable or movable.
+  Hook(const Hook&) = delete;
+  Hook& operator=(const Hook&) = delete;
+
  private:
   std::string name_;
   std::optional<HookCallback> default_;
@@ -41,9 +45,10 @@ class Hook {
 class TriggerHooks {
  public:
   TriggerHooks(std::string name, std::optional<HookCallback> cb)
-      : TriggerHooks(name, cb, cb, cb) {}
+      : TriggerHooks(name, cb, cb, cb, cb) {}
   TriggerHooks(std::string name,
                std::optional<HookCallback> click,
+               std::optional<HookCallback> double_click,
                std::optional<HookCallback> long_press,
                std::optional<HookCallback> repeat);
 
@@ -51,13 +56,20 @@ class TriggerHooks {
   auto override(Trigger::State, std::optional<HookCallback>) -> void;
 
   auto name() const -> const std::string&;
-  auto pushHooks(lua_State*) -> void;
+  auto hooks() -> std::vector<std::reference_wrapper<Hook>>;
+
+  auto cancel() -> void;
+
+  // Not copyable or movable.
+  TriggerHooks(const TriggerHooks&) = delete;
+  TriggerHooks& operator=(const TriggerHooks&) = delete;
 
  private:
   std::string name_;
   Trigger trigger_;
 
   Hook click_;
+  Hook double_click_;
   Hook long_press_;
   Hook repeat_;
 };
diff --git a/src/input/input_hook_actions.cpp b/src/tangara/input/input_hook_actions.cpp
index 26075c4c..bc3760ac 100644
--- a/src/input/input_hook_actions.cpp
+++ b/src/tangara/input/input_hook_actions.cpp
@@ -4,14 +4,14 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "input_hook_actions.hpp"
+#include "input/input_hook_actions.hpp"
 
 #include <cstdint>
 
 #include "hal/lv_hal_indev.h"
 
-#include "event_queue.hpp"
-#include "ui_events.hpp"
+#include "events/event_queue.hpp"
+#include "ui/ui_events.hpp"
 
 namespace input {
 namespace actions {
diff --git a/src/input/include/input_hook_actions.hpp b/src/tangara/input/input_hook_actions.hpp
index 105bd10d..71a560bc 100644
--- a/src/input/include/input_hook_actions.hpp
+++ b/src/tangara/input/input_hook_actions.hpp
@@ -7,7 +7,7 @@
 #pragma once
 
 #include "hal/lv_hal_indev.h"
-#include "input_hook.hpp"
+#include "input/input_hook.hpp"
 
 namespace input {
 namespace actions {
diff --git a/src/input/input_nav_buttons.cpp b/src/tangara/input/input_nav_buttons.cpp
index 7e579a16..ba1f4b74 100644
--- a/src/input/input_nav_buttons.cpp
+++ b/src/tangara/input/input_nav_buttons.cpp
@@ -4,19 +4,19 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "input_nav_buttons.hpp"
+#include "input/input_nav_buttons.hpp"
 
-#include "event_queue.hpp"
-#include "gpios.hpp"
+#include "drivers/gpios.hpp"
+#include "events/event_queue.hpp"
 #include "hal/lv_hal_indev.h"
-#include "input_hook_actions.hpp"
+#include "input/input_hook_actions.hpp"
 
 namespace input {
 
 NavButtons::NavButtons(drivers::IGpios& gpios)
     : gpios_(gpios),
-      up_("upper", actions::scrollUp(), actions::select(), {}),
-      down_("lower", actions::scrollDown(), actions::select(), {}) {}
+      up_("upper", {}, actions::scrollUp(), actions::select(), {}),
+      down_("lower", {}, actions::scrollDown(), actions::select(), {}) {}
 
 auto NavButtons::read(lv_indev_data_t* data) -> void {
   up_.update(!gpios_.Get(drivers::IGpios::Pin::kKeyUp), data);
@@ -27,7 +27,8 @@ auto NavButtons::name() -> std::string {
   return "buttons";
 }
 
-auto NavButtons::hooks() -> std::vector<TriggerHooks> {
+auto NavButtons::triggers()
+    -> std::vector<std::reference_wrapper<TriggerHooks>> {
   return {up_, down_};
 }
 
diff --git a/src/input/include/input_nav_buttons.hpp b/src/tangara/input/input_nav_buttons.hpp
index 4e4952c9..ce2312a0 100644
--- a/src/input/include/input_nav_buttons.hpp
+++ b/src/tangara/input/input_nav_buttons.hpp
@@ -8,14 +8,14 @@
 
 #include <cstdint>
 
-#include "gpios.hpp"
+#include "drivers/gpios.hpp"
 #include "hal/lv_hal_indev.h"
 
-#include "haptics.hpp"
-#include "input_device.hpp"
-#include "input_hook.hpp"
-#include "input_trigger.hpp"
-#include "touchwheel.hpp"
+#include "drivers/haptics.hpp"
+#include "input/input_device.hpp"
+#include "input/input_hook.hpp"
+#include "input/input_trigger.hpp"
+#include "drivers/touchwheel.hpp"
 
 namespace input {
 
@@ -26,7 +26,7 @@ class NavButtons : public IInputDevice {
   auto read(lv_indev_data_t* data) -> void override;
 
   auto name() -> std::string override;
-  auto hooks() -> std::vector<TriggerHooks> override;
+  auto triggers() -> std::vector<std::reference_wrapper<TriggerHooks>> override;
 
  private:
   drivers::IGpios& gpios_;
diff --git a/src/input/input_touch_dpad.cpp b/src/tangara/input/input_touch_dpad.cpp
index f0805993..5d8e2dab 100644
--- a/src/input/input_touch_dpad.cpp
+++ b/src/tangara/input/input_touch_dpad.cpp
@@ -4,28 +4,29 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "input_touch_dpad.hpp"
+#include "input/input_touch_dpad.hpp"
 
 #include <cstdint>
 
 #include "hal/lv_hal_indev.h"
 
-#include "event_queue.hpp"
-#include "haptics.hpp"
-#include "input_device.hpp"
-#include "input_hook_actions.hpp"
-#include "input_touch_dpad.hpp"
-#include "touchwheel.hpp"
+#include "drivers/haptics.hpp"
+#include "drivers/touchwheel.hpp"
+
+#include "events/event_queue.hpp"
+#include "input/input_device.hpp"
+#include "input/input_hook_actions.hpp"
+#include "input/input_touch_dpad.hpp"
 
 namespace input {
 
 TouchDPad::TouchDPad(drivers::TouchWheel& wheel)
     : wheel_(wheel),
-      centre_("centre", actions::select(), {}, {}),
-      up_("up", actions::scrollUp()),
-      right_("right", {}, {}, {}),
-      down_("down", actions::scrollDown()),
-      left_("left", actions::goBack()) {}
+      centre_("centre", actions::select(), {}, {}, {}),
+      up_("up", actions::scrollUp(), {}, {}, actions::scrollUp()),
+      right_("right", actions::select(), {}, {}, {}),
+      down_("down", actions::scrollDown(), {}, {}, actions::scrollDown()),
+      left_("left", actions::goBack(), {}, {}, {}) {}
 
 auto TouchDPad::read(lv_indev_data_t* data) -> void {
   wheel_.Update();
@@ -55,7 +56,8 @@ auto TouchDPad::name() -> std::string {
   return "dpad";
 }
 
-auto TouchDPad::hooks() -> std::vector<TriggerHooks> {
+auto TouchDPad::triggers()
+    -> std::vector<std::reference_wrapper<TriggerHooks>> {
   return {centre_, up_, right_, down_, left_};
 }
 
diff --git a/src/input/include/input_touch_dpad.hpp b/src/tangara/input/input_touch_dpad.hpp
index 691e3243..8fb14832 100644
--- a/src/input/include/input_touch_dpad.hpp
+++ b/src/tangara/input/input_touch_dpad.hpp
@@ -10,11 +10,11 @@
 
 #include "hal/lv_hal_indev.h"
 
-#include "haptics.hpp"
-#include "input_device.hpp"
-#include "input_hook.hpp"
-#include "input_trigger.hpp"
-#include "touchwheel.hpp"
+#include "drivers/haptics.hpp"
+#include "input/input_device.hpp"
+#include "input/input_hook.hpp"
+#include "input/input_trigger.hpp"
+#include "drivers/touchwheel.hpp"
 
 namespace input {
 
@@ -25,7 +25,7 @@ class TouchDPad : public IInputDevice {
   auto read(lv_indev_data_t* data) -> void override;
 
   auto name() -> std::string override;
-  auto hooks() -> std::vector<TriggerHooks> override;
+  auto triggers() -> std::vector<std::reference_wrapper<TriggerHooks>> override;
 
  private:
   drivers::TouchWheel& wheel_;
diff --git a/src/input/input_touch_wheel.cpp b/src/tangara/input/input_touch_wheel.cpp
index 121b1ee5..75159320 100644
--- a/src/input/input_touch_wheel.cpp
+++ b/src/tangara/input/input_touch_wheel.cpp
@@ -4,22 +4,22 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "input_touch_wheel.hpp"
+#include "input/input_touch_wheel.hpp"
 
 #include <cstdint>
 #include <variant>
 
 #include "hal/lv_hal_indev.h"
 
-#include "event_queue.hpp"
-#include "haptics.hpp"
-#include "input_device.hpp"
-#include "input_hook_actions.hpp"
-#include "input_trigger.hpp"
-#include "nvs.hpp"
-#include "property.hpp"
-#include "touchwheel.hpp"
-#include "ui_events.hpp"
+#include "drivers/haptics.hpp"
+#include "drivers/nvs.hpp"
+#include "drivers/touchwheel.hpp"
+#include "events/event_queue.hpp"
+#include "input/input_device.hpp"
+#include "input/input_hook_actions.hpp"
+#include "input/input_trigger.hpp"
+#include "lua/property.hpp"
+#include "ui/ui_events.hpp"
 
 namespace input {
 
@@ -39,11 +39,11 @@ TouchWheel::TouchWheel(drivers::NvsStorage& nvs, drivers::TouchWheel& wheel)
                      threshold_ = calculateThreshold(int_val);
                      return true;
                    }),
-      centre_("centre", actions::select(), {}, {}),
-      up_("up", {}, actions::scrollToTop(), actions::scrollUp()),
-      right_("right", {}, {}, {}),
-      down_("down", {}, actions::scrollToBottom(), actions::scrollDown()),
-      left_("left", {}, actions::goBack(), {}),
+      centre_("centre", actions::select(), {}, {}, {}),
+      up_("up", {}, {}, actions::scrollToTop(), {}),
+      right_("right", {}),
+      down_("down", {}, {}, actions::scrollToBottom(), {}),
+      left_("left", {}, {}, actions::goBack(), {}),
       is_scrolling_(false),
       threshold_(calculateThreshold(nvs.ScrollSensitivity())),
       is_first_read_(true),
@@ -68,31 +68,39 @@ auto TouchWheel::read(lv_indev_data_t* data) -> void {
     data->enc_diff = 0;
   }
 
-  centre_.update(!is_scrolling_ && wheel_data.is_button_touched, data);
+  centre_.update(wheel_data.is_button_touched && !wheel_data.is_wheel_touched,
+                 data);
 
   // If the user is touching the wheel but not scrolling, then they may be
   // clicking on one of the wheel's cardinal directions.
-  bool pressing = wheel_data.is_wheel_touched && !is_scrolling_;
-
-  up_.update(pressing && drivers::TouchWheel::isAngleWithin(
-                             wheel_data.wheel_position, 0, 32),
-             data);
-  right_.update(pressing && drivers::TouchWheel::isAngleWithin(
-                                wheel_data.wheel_position, 192, 32),
-                data);
-  down_.update(pressing && drivers::TouchWheel::isAngleWithin(
-                               wheel_data.wheel_position, 128, 32),
-               data);
-  left_.update(pressing && drivers::TouchWheel::isAngleWithin(
-                               wheel_data.wheel_position, 64, 32),
+  if (is_scrolling_) {
+    up_.cancel();
+    right_.cancel();
+    down_.cancel();
+    left_.cancel();
+  } else {
+    bool pressing = wheel_data.is_wheel_touched;
+    up_.update(pressing && drivers::TouchWheel::isAngleWithin(
+                               wheel_data.wheel_position, 0, 32),
                data);
+    right_.update(pressing && drivers::TouchWheel::isAngleWithin(
+                                  wheel_data.wheel_position, 192, 32),
+                  data);
+    down_.update(pressing && drivers::TouchWheel::isAngleWithin(
+                                 wheel_data.wheel_position, 128, 32),
+                 data);
+    left_.update(pressing && drivers::TouchWheel::isAngleWithin(
+                                 wheel_data.wheel_position, 64, 32),
+                 data);
+  }
 }
 
 auto TouchWheel::name() -> std::string {
   return "wheel";
 }
 
-auto TouchWheel::hooks() -> std::vector<TriggerHooks> {
+auto TouchWheel::triggers()
+    -> std::vector<std::reference_wrapper<TriggerHooks>> {
   return {centre_, up_, right_, down_, left_};
 }
 
diff --git a/src/input/include/input_touch_wheel.hpp b/src/tangara/input/input_touch_wheel.hpp
index 1f116da9..d023873a 100644
--- a/src/input/include/input_touch_wheel.hpp
+++ b/src/tangara/input/input_touch_wheel.hpp
@@ -11,13 +11,13 @@
 
 #include "hal/lv_hal_indev.h"
 
-#include "haptics.hpp"
-#include "input_device.hpp"
-#include "input_hook.hpp"
-#include "input_trigger.hpp"
-#include "nvs.hpp"
-#include "property.hpp"
-#include "touchwheel.hpp"
+#include "drivers/haptics.hpp"
+#include "input/input_device.hpp"
+#include "input/input_hook.hpp"
+#include "input/input_trigger.hpp"
+#include "lua/property.hpp"
+#include "drivers/nvs.hpp"
+#include "drivers/touchwheel.hpp"
 
 namespace input {
 
@@ -28,7 +28,7 @@ class TouchWheel : public IInputDevice {
   auto read(lv_indev_data_t* data) -> void override;
 
   auto name() -> std::string override;
-  auto hooks() -> std::vector<TriggerHooks> override;
+  auto triggers() -> std::vector<std::reference_wrapper<TriggerHooks>> override;
 
   auto sensitivity() -> lua::Property&;
 
diff --git a/src/input/input_trigger.cpp b/src/tangara/input/input_trigger.cpp
index 9485ecb4..eb67bcca 100644
--- a/src/input/input_trigger.cpp
+++ b/src/tangara/input/input_trigger.cpp
@@ -4,38 +4,54 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "input_trigger.hpp"
-#include <sys/_stdint.h>
+#include "input/input_trigger.hpp"
 
 #include <cstdint>
-#include "esp_log.h"
+
 #include "esp_timer.h"
 
 namespace input {
 
-Trigger::Trigger() : touch_time_ms_(), times_fired_(0) {}
+Trigger::Trigger()
+    : touch_time_ms_(),
+      was_pressed_(false),
+      was_double_click_(false),
+      times_long_pressed_(0) {}
 
 auto Trigger::update(bool is_pressed) -> State {
   // Bail out early if we're in a steady-state of not pressed.
-  if (!is_pressed && !touch_time_ms_) {
+  if (!is_pressed && !was_pressed_) {
+    was_double_click_ = false;
+    times_long_pressed_ = 0;
     return State::kNone;
   }
 
   uint64_t now_ms = esp_timer_get_time() / 1000;
 
-  // Initial press of this key: record the current time, and report that we
-  // haven't triggered yet.
-  if (is_pressed && !touch_time_ms_) {
+  // This key wasn't being pressed, but now it is.
+  if (is_pressed && !was_pressed_) {
+    // Is this a double click?
+    if (now_ms - *touch_time_ms_ < kDoubleClickDelayMs) {
+      // Don't update touch_time_ms_, since we don't want triple clicks to
+      // register as double clicks.
+      was_double_click_ = true;
+      was_pressed_ = true;
+      return State::kDoubleClick;
+    }
+    // Not a double click; update our accounting info and wait for the next
+    // call.
     touch_time_ms_ = now_ms;
-    times_fired_ = 0;
+    was_double_click_ = false;
+    times_long_pressed_ = 0;
+    was_pressed_ = true;
     return State::kNone;
   }
 
   // The key was released. If there were no long-press events fired during the
   // press, then this was a standard click.
-  if (!is_pressed && touch_time_ms_) {
-    touch_time_ms_.reset();
-    if (times_fired_ == 0) {
+  if (!is_pressed && was_pressed_) {
+    was_pressed_ = false;
+    if (!was_double_click_ && times_long_pressed_ == 0) {
       return State::kClick;
     } else {
       return State::kNone;
@@ -43,10 +59,10 @@ auto Trigger::update(bool is_pressed) -> State {
   }
 
   // Now the more complicated case: the user is continuing to press the button.
-  if (times_fired_ == 0) {
+  if (times_long_pressed_ == 0) {
     // We haven't fired yet, so we wait for the long-press event.
     if (now_ms - *touch_time_ms_ >= kLongPressDelayMs) {
-      times_fired_++;
+      times_long_pressed_++;
       return State::kLongPress;
     }
   } else {
@@ -60,8 +76,8 @@ auto Trigger::update(bool is_pressed) -> State {
     // kRepeatDelayMs since the long-press event.
     uint16_t expected_times_fired =
         1 + (time_since_long_press / kRepeatDelayMs);
-    if (times_fired_ < expected_times_fired) {
-      times_fired_++;
+    if (times_long_pressed_ < expected_times_fired) {
+      times_long_pressed_++;
       return State::kRepeatPress;
     }
   }
@@ -69,4 +85,11 @@ auto Trigger::update(bool is_pressed) -> State {
   return State::kNone;
 }
 
+auto Trigger::cancel() -> void {
+  touch_time_ms_.reset();
+  was_pressed_ = false;
+  was_double_click_ = false;
+  times_long_pressed_ = 0;
+}
+
 }  // namespace input
diff --git a/src/input/include/input_trigger.hpp b/src/tangara/input/input_trigger.hpp
index 599b796b..1b0e681d 100644
--- a/src/input/include/input_trigger.hpp
+++ b/src/tangara/input/input_trigger.hpp
@@ -13,6 +13,7 @@
 
 namespace input {
 
+const uint16_t kDoubleClickDelayMs = 500;
 const uint16_t kLongPressDelayMs = LV_INDEV_DEF_LONG_PRESS_TIME;
 const uint16_t kRepeatDelayMs = LV_INDEV_DEF_LONG_PRESS_REP_TIME;
 
@@ -21,6 +22,7 @@ class Trigger {
   enum class State {
     kNone,
     kClick,
+    kDoubleClick,
     kLongPress,
     kRepeatPress,
   };
@@ -28,10 +30,14 @@ class Trigger {
   Trigger();
 
   auto update(bool is_pressed) -> State;
+  auto cancel() -> void;
 
  private:
   std::optional<uint64_t> touch_time_ms_;
-  uint16_t times_fired_;
+  bool was_pressed_;
+
+  bool was_double_click_;
+  uint16_t times_long_pressed_;
 };
 
 }  // namespace input
diff --git a/src/input/input_volume_buttons.cpp b/src/tangara/input/input_volume_buttons.cpp
index 607f81f1..3c3fb2a3 100644
--- a/src/input/input_volume_buttons.cpp
+++ b/src/tangara/input/input_volume_buttons.cpp
@@ -4,10 +4,10 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "input_volume_buttons.hpp"
-#include "event_queue.hpp"
-#include "gpios.hpp"
-#include "input_hook_actions.hpp"
+#include "input/input_volume_buttons.hpp"
+#include "drivers/gpios.hpp"
+#include "events/event_queue.hpp"
+#include "input/input_hook_actions.hpp"
 
 namespace input {
 
@@ -25,7 +25,8 @@ auto VolumeButtons::name() -> std::string {
   return "buttons";
 }
 
-auto VolumeButtons::hooks() -> std::vector<TriggerHooks> {
+auto VolumeButtons::triggers()
+    -> std::vector<std::reference_wrapper<TriggerHooks>> {
   return {up_, down_};
 }
 
diff --git a/src/input/include/input_volume_buttons.hpp b/src/tangara/input/input_volume_buttons.hpp
index a684aa48..22a8acf2 100644
--- a/src/input/include/input_volume_buttons.hpp
+++ b/src/tangara/input/input_volume_buttons.hpp
@@ -8,13 +8,13 @@
 
 #include <cstdint>
 
-#include "gpios.hpp"
+#include "drivers/gpios.hpp"
 #include "hal/lv_hal_indev.h"
 
-#include "haptics.hpp"
-#include "input_device.hpp"
-#include "input_hook.hpp"
-#include "touchwheel.hpp"
+#include "drivers/haptics.hpp"
+#include "input/input_device.hpp"
+#include "input/input_hook.hpp"
+#include "drivers/touchwheel.hpp"
 
 namespace input {
 
@@ -25,7 +25,7 @@ class VolumeButtons : public IInputDevice {
   auto read(lv_indev_data_t* data) -> void override;
 
   auto name() -> std::string override;
-  auto hooks() -> std::vector<TriggerHooks> override;
+  auto triggers() -> std::vector<std::reference_wrapper<TriggerHooks>> override;
 
  private:
   drivers::IGpios& gpios_;
diff --git a/src/tangara/input/lvgl_input_driver.cpp b/src/tangara/input/lvgl_input_driver.cpp
new file mode 100644
index 00000000..8d10bb13
--- /dev/null
+++ b/src/tangara/input/lvgl_input_driver.cpp
@@ -0,0 +1,258 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "input/lvgl_input_driver.hpp"
+
+#include <cstdint>
+#include <memory>
+#include <variant>
+
+#include "lua.hpp"
+#include "lvgl.h"
+
+#include "drivers/nvs.hpp"
+
+#include "input/device_factory.hpp"
+#include "input/feedback_haptics.hpp"
+#include "input/input_hook.hpp"
+#include "input/input_touch_wheel.hpp"
+#include "input/input_trigger.hpp"
+#include "input/input_volume_buttons.hpp"
+#include "lua/lua_thread.hpp"
+#include "lua/property.hpp"
+
+[[maybe_unused]] static constexpr char kTag[] = "input";
+
+static constexpr char kLuaTriggerMetatableName[] = "input_trigger";
+static constexpr char kLuaOverrideText[] = "lua_callback";
+
+namespace input {
+
+static void read_cb(lv_indev_drv_t* drv, lv_indev_data_t* data) {
+  LvglInputDriver* instance =
+      reinterpret_cast<LvglInputDriver*>(drv->user_data);
+  instance->read(data);
+}
+
+static void feedback_cb(lv_indev_drv_t* drv, uint8_t event) {
+  LvglInputDriver* instance =
+      reinterpret_cast<LvglInputDriver*>(drv->user_data);
+  instance->feedback(event);
+}
+
+auto intToMode(int raw) -> std::optional<drivers::NvsStorage::InputModes> {
+  switch (raw) {
+    case 0:
+      return drivers::NvsStorage::InputModes::kButtonsOnly;
+    case 1:
+      return drivers::NvsStorage::InputModes::kButtonsWithWheel;
+    case 2:
+      return drivers::NvsStorage::InputModes::kDirectionalWheel;
+    case 3:
+      return drivers::NvsStorage::InputModes::kRotatingWheel;
+    default:
+      return {};
+  }
+}
+
+LvglInputDriver::LvglInputDriver(drivers::NvsStorage& nvs,
+                                 DeviceFactory& factory)
+    : nvs_(nvs),
+      factory_(factory),
+      mode_(static_cast<int>(nvs.PrimaryInput()),
+            [&](const lua::LuaValue& val) {
+              if (!std::holds_alternative<int>(val)) {
+                return false;
+              }
+              auto mode = intToMode(std::get<int>(val));
+              if (!mode) {
+                return false;
+              }
+              nvs.PrimaryInput(*mode);
+              inputs_ = factory.createInputs(*mode);
+              return true;
+            }),
+      driver_(),
+      registration_(nullptr),
+      inputs_(factory.createInputs(nvs.PrimaryInput())),
+      feedbacks_(factory.createFeedbacks()),
+      is_locked_(false) {
+  lv_indev_drv_init(&driver_);
+  driver_.type = LV_INDEV_TYPE_ENCODER;
+  driver_.read_cb = read_cb;
+  driver_.feedback_cb = feedback_cb;
+  driver_.user_data = this;
+  driver_.long_press_time = kLongPressDelayMs;
+  driver_.long_press_repeat_time = kRepeatDelayMs;
+
+  registration_ = lv_indev_drv_register(&driver_);
+}
+
+auto LvglInputDriver::read(lv_indev_data_t* data) -> void {
+  // TODO: we should pass lock state on to the individual devices, since they
+  // may wish to either ignore the lock state, or power down until unlock.
+  if (is_locked_) {
+    return;
+  }
+  for (auto&& device : inputs_) {
+    device->read(data);
+  }
+}
+
+auto LvglInputDriver::feedback(uint8_t event) -> void {
+  if (is_locked_) {
+    return;
+  }
+  for (auto&& device : feedbacks_) {
+    device->feedback(event);
+  }
+}
+
+LvglInputDriver::LuaTrigger::LuaTrigger(LvglInputDriver& driver,
+                                        IInputDevice& dev,
+                                        TriggerHooks& trigger)
+    : driver_(&driver), device_(dev.name()), trigger_(trigger.name()) {
+  for (auto& hook : trigger.hooks()) {
+    auto cb = hook.get().callback();
+    if (cb) {
+      hooks_[hook.get().name()] = hook.get().callback()->name;
+    } else {
+      hooks_[hook.get().name()] = "";
+    }
+  }
+}
+
+auto LvglInputDriver::LuaTrigger::get(lua_State* L, int idx) -> LuaTrigger& {
+  return **reinterpret_cast<LuaTrigger**>(
+      luaL_checkudata(L, idx, kLuaTriggerMetatableName));
+}
+
+auto LvglInputDriver::LuaTrigger::luaGc(lua_State* L) -> int {
+  LuaTrigger& trigger = LuaTrigger::get(L, 1);
+  delete &trigger;
+  return 0;
+}
+
+auto LvglInputDriver::LuaTrigger::luaToString(lua_State* L) -> int {
+  LuaTrigger& trigger = LuaTrigger::get(L, 1);
+  std::stringstream out;
+  out << "{ ";
+  for (const auto& hook : trigger.hooks_) {
+    if (!hook.second.empty()) {
+      out << hook.first << "=" << hook.second << " ";
+    }
+  }
+  out << "}";
+  lua_pushlstring(L, out.str().data(), out.str().size());
+  return 1;
+}
+
+auto LvglInputDriver::LuaTrigger::luaNewIndex(lua_State* L) -> int {
+  LuaTrigger& trigger = LuaTrigger::get(L, 1);
+  luaL_checktype(L, 3, LUA_TFUNCTION);
+
+  size_t len = 0;
+  const char* str = luaL_checklstring(L, 2, &len);
+  if (!str) {
+    return 0;
+  }
+  OverrideSelector selector{
+      .device_name = trigger.device_,
+      .trigger_name = trigger.trigger_,
+      .hook_name = std::string{str, len},
+  };
+  for (const auto& hook : trigger.hooks_) {
+    if (hook.first == selector.hook_name) {
+      trigger.driver_->setOverride(L, selector);
+      trigger.hooks_[hook.first] = kLuaOverrideText;
+      return 0;
+    }
+  }
+  return 0;
+}
+
+auto LvglInputDriver::pushHooks(lua_State* L) -> int {
+  if (luaL_getmetatable(L, kLuaTriggerMetatableName) == LUA_TNIL) {
+    luaL_newmetatable(L, kLuaTriggerMetatableName);
+    luaL_setfuncs(L, LuaTrigger::kFuncs, 0);
+    lua_pop(L, 1);
+  }
+  lua_pop(L, 1);
+
+  lua_newtable(L);
+
+  for (auto& dev : inputs_) {
+    lua_pushlstring(L, dev->name().data(), dev->name().size());
+    lua_newtable(L);
+
+    for (auto& trigger : dev->triggers()) {
+      lua_pushlstring(L, trigger.get().name().data(),
+                      trigger.get().name().size());
+      LuaTrigger** lua_obj = reinterpret_cast<LuaTrigger**>(
+          lua_newuserdatauv(L, sizeof(LuaTrigger*), 0));
+      *lua_obj = new LuaTrigger(*this, *dev, trigger);
+      luaL_setmetatable(L, kLuaTriggerMetatableName);
+      lua_rawset(L, -3);
+    }
+
+    lua_rawset(L, -3);
+  }
+
+  return 1;
+}
+
+auto LvglInputDriver::setOverride(lua_State* L,
+                                  const OverrideSelector& selector) -> void {
+  if (overrides_.contains(selector)) {
+    LuaOverride& prev = overrides_[selector];
+    luaL_unref(prev.L, LUA_REGISTRYINDEX, prev.ref);
+  }
+
+  int ref = luaL_ref(L, LUA_REGISTRYINDEX);
+  LuaOverride override{
+      .L = L,
+      .ref = ref,
+  };
+  overrides_[selector] = override;
+  applyOverride(selector, override);
+}
+
+auto LvglInputDriver::applyOverride(const OverrideSelector& selector,
+                                    LuaOverride& override) -> void {
+  // In general, this algorithm is a very slow approach. We could do better
+  // by maintaing maps from [device|trigger|hook]_name to the relevant
+  // trigger, but in practice I expect maybe like 5 overrides total ever,
+  // spread across 2 devices with 2 or 5 hooks each. So it's not that big a
+  // deal. Don't worry about it!!
+
+  // Look for a matching device.
+  for (auto& device : inputs_) {
+    if (device->name() != selector.device_name) {
+      continue;
+    }
+    // Look for a matching trigger
+    for (auto& trigger : device->triggers()) {
+      if (trigger.get().name() != selector.trigger_name) {
+        continue;
+      }
+      // Look for a matching hook
+      for (auto& hook : trigger.get().hooks()) {
+        if (hook.get().name() != selector.hook_name) {
+          continue;
+        }
+        // We found the target! Apply the override.
+        auto lua_callback = [=](lv_indev_data_t* d) {
+          lua_rawgeti(override.L, LUA_REGISTRYINDEX, override.ref);
+          lua::CallProtected(override.L, 0, 0);
+        };
+        hook.get().override(
+            HookCallback{.name = kLuaOverrideText, .fn = lua_callback});
+      }
+    }
+  }
+}
+
+}  // namespace input
diff --git a/src/tangara/input/lvgl_input_driver.hpp b/src/tangara/input/lvgl_input_driver.hpp
new file mode 100644
index 00000000..8ede1855
--- /dev/null
+++ b/src/tangara/input/lvgl_input_driver.hpp
@@ -0,0 +1,112 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <deque>
+#include <memory>
+#include <set>
+
+#include "core/lv_group.h"
+#include "drivers/gpios.hpp"
+#include "hal/lv_hal_indev.h"
+#include "input/device_factory.hpp"
+#include "input/feedback_device.hpp"
+
+#include "input/input_device.hpp"
+#include "input/input_hook.hpp"
+#include "lua/lua_thread.hpp"
+#include "lua/property.hpp"
+#include "drivers/nvs.hpp"
+#include "drivers/touchwheel.hpp"
+
+namespace input {
+
+/*
+ * Implementation of an LVGL input device. This class composes multiple
+ * IInputDevice and IFeedbackDevice instances together into a single LVGL
+ * device.
+ */
+class LvglInputDriver {
+ public:
+  LvglInputDriver(drivers::NvsStorage& nvs, DeviceFactory&);
+
+  auto mode() -> lua::Property& { return mode_; }
+
+  auto read(lv_indev_data_t* data) -> void;
+  auto feedback(uint8_t) -> void;
+
+  auto registration() -> lv_indev_t* { return registration_; }
+  auto lock(bool l) -> void { is_locked_ = l; }
+
+  auto pushHooks(lua_State* L) -> int;
+
+ private:
+  drivers::NvsStorage& nvs_;
+  DeviceFactory& factory_;
+
+  lua::Property mode_;
+  lv_indev_drv_t driver_;
+  lv_indev_t* registration_;
+
+  std::vector<std::shared_ptr<IInputDevice>> inputs_;
+  std::vector<std::shared_ptr<IFeedbackDevice>> feedbacks_;
+
+  /*
+   * Key for identifying which device, trigger, and specific hook are being
+   * overriden by Lua.
+   */
+  struct OverrideSelector {
+    std::string device_name;
+    std::string trigger_name;
+    std::string hook_name;
+
+    friend bool operator<(const OverrideSelector& l,
+                          const OverrideSelector& r) {
+      return std::tie(l.device_name, l.trigger_name, l.hook_name) <
+             std::tie(r.device_name, r.trigger_name, r.hook_name);
+    }
+  };
+
+  /* Userdata object for tracking the Lua mirror of a TriggerHooks object. */
+  class LuaTrigger {
+   public:
+    LuaTrigger(LvglInputDriver&, IInputDevice&, TriggerHooks&);
+
+    static auto get(lua_State*, int idx) -> LuaTrigger&;
+    static auto luaGc(lua_State*) -> int;
+    static auto luaToString(lua_State*) -> int;
+    static auto luaNewIndex(lua_State*) -> int;
+
+    static constexpr struct luaL_Reg kFuncs[] = {{"__gc", luaGc},
+                                                 {"__tostring", luaToString},
+                                                 {"__newindex", luaNewIndex},
+                                                 {NULL, NULL}};
+
+   private:
+    LvglInputDriver* driver_;
+
+    std::string device_;
+    std::string trigger_;
+    std::map<std::string, std::string> hooks_;
+  };
+
+  /* A hook override implemented as a lua callback */
+  struct LuaOverride {
+    lua_State* L;
+    int ref;
+  };
+
+  std::map<OverrideSelector, LuaOverride> overrides_;
+
+  auto setOverride(lua_State* L, const OverrideSelector&) -> void;
+  auto applyOverride(const OverrideSelector&, LuaOverride&) -> void;
+
+  bool is_locked_;
+};
+
+}  // namespace input
diff --git a/src/lua/bridge.cpp b/src/tangara/lua/bridge.cpp
index a84eb0c1..07c299a7 100644
--- a/src/lua/bridge.cpp
+++ b/src/tangara/lua/bridge.cpp
@@ -4,34 +4,33 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "bridge.hpp"
-#include <sys/_stdint.h>
+#include "lua/bridge.hpp"
 
+#include <cstdint>
 #include <memory>
 #include <string>
 
-#include "database.hpp"
+#include "database/database.hpp"
+#include "database/index.hpp"
 #include "esp_log.h"
-#include "index.hpp"
 #include "lauxlib.h"
 #include "lua.h"
 #include "lua.hpp"
-#include "lua_controls.hpp"
-#include "lua_database.hpp"
-#include "lua_filesystem.hpp"
-#include "lua_queue.hpp"
-#include "lua_screen.hpp"
-#include "lua_version.hpp"
-#include "lua_theme.hpp"
+#include "lua/lua_controls.hpp"
+#include "lua/lua_database.hpp"
+#include "lua/lua_queue.hpp"
+#include "lua/lua_screen.hpp"
+#include "lua/lua_theme.hpp"
+#include "lua/lua_version.hpp"
 #include "lvgl.h"
 
 #include "font/lv_font_loader.h"
 #include "luavgl.h"
 
-#include "event_queue.hpp"
-#include "property.hpp"
-#include "service_locator.hpp"
-#include "ui_events.hpp"
+#include "events/event_queue.hpp"
+#include "lua/property.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "ui/ui_events.hpp"
 
 extern "C" {
 int luaopen_linenoise(lua_State* L);
@@ -47,8 +46,9 @@ namespace lua {
 
 static constexpr char kBridgeKey[] = "bridge";
 
-static auto make_font_cb(const char* name, int size, int weight)
-    -> const lv_font_t* {
+static auto make_font_cb(const char* name,
+                         int size,
+                         int weight) -> const lv_font_t* {
   if (std::string{"fusion"} == name) {
     if (size == 12) {
       return &font_fusion_12;
@@ -85,7 +85,6 @@ auto Bridge::installBaseModules(lua_State* L) -> void {
 
   RegisterControlsModule(L);
   RegisterDatabaseModule(L);
-  RegisterFileSystemModule(L);
   RegisterQueueModule(L);
   RegisterVersionModule(L);
   RegisterThemeModule(L);
diff --git a/src/lua/include/bridge.hpp b/src/tangara/lua/bridge.hpp
index 64f14e0e..b4cfe503 100644
--- a/src/lua/include/bridge.hpp
+++ b/src/tangara/lua/bridge.hpp
@@ -10,9 +10,9 @@
 #include <string>
 
 #include "lua.hpp"
+#include "lua/property.hpp"
 #include "lvgl.h"
-#include "property.hpp"
-#include "service_locator.hpp"
+#include "system_fsm/service_locator.hpp"
 
 namespace lua {
 
@@ -39,9 +39,8 @@ class Bridge {
   auto installPropertyModule(
       lua_State* L,
       const std::string&,
-      std::vector<
-          std::pair<std::string, std::variant<LuaFunction, Property*>>>&)
-      -> void;
+      std::vector<std::pair<std::string,
+                            std::variant<LuaFunction, Property*>>>&) -> void;
 
   Bridge(const Bridge&) = delete;
   Bridge& operator=(const Bridge&) = delete;
diff --git a/src/lua/file_iterator.cpp b/src/tangara/lua/file_iterator.cpp
index 194859a6..194859a6 100644
--- a/src/lua/file_iterator.cpp
+++ b/src/tangara/lua/file_iterator.cpp
diff --git a/src/lua/include/file_iterator.hpp b/src/tangara/lua/file_iterator.hpp
index 82d6f397..82d6f397 100644
--- a/src/lua/include/file_iterator.hpp
+++ b/src/tangara/lua/file_iterator.hpp
diff --git a/src/lua/lua_controls.cpp b/src/tangara/lua/lua_controls.cpp
index 2da0ed11..baf40891 100644
--- a/src/lua/lua_controls.cpp
+++ b/src/tangara/lua/lua_controls.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "lua_controls.hpp"
+#include "lua/lua_controls.hpp"
 
 #include <memory>
 #include <string>
@@ -16,8 +16,8 @@
 #include "lua.h"
 #include "lvgl.h"
 
-#include "nvs.hpp"
-#include "ui_events.hpp"
+#include "drivers/nvs.hpp"
+#include "ui/ui_events.hpp"
 
 namespace lua {
 
diff --git a/src/lua/include/lua_controls.hpp b/src/tangara/lua/lua_controls.hpp
index 18ad261d..18ad261d 100644
--- a/src/lua/include/lua_controls.hpp
+++ b/src/tangara/lua/lua_controls.hpp
diff --git a/src/lua/lua_database.cpp b/src/tangara/lua/lua_database.cpp
index d0612fdd..1afb01f0 100644
--- a/src/lua/lua_database.cpp
+++ b/src/tangara/lua/lua_database.cpp
@@ -4,30 +4,30 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "lua_database.hpp"
+#include "lua/lua_database.hpp"
 
 #include <memory>
 #include <string>
 #include <type_traits>
 #include <variant>
 
-#include "bridge.hpp"
 #include "lua.hpp"
+#include "lua/bridge.hpp"
 
 #include "esp_log.h"
 #include "lauxlib.h"
 #include "lua.h"
-#include "lua_thread.hpp"
+#include "lua/lua_thread.hpp"
 #include "lvgl.h"
 
-#include "database.hpp"
-#include "event_queue.hpp"
-#include "index.hpp"
-#include "property.hpp"
-#include "records.hpp"
-#include "service_locator.hpp"
-#include "track.hpp"
-#include "ui_events.hpp"
+#include "database/database.hpp"
+#include "database/index.hpp"
+#include "database/records.hpp"
+#include "database/track.hpp"
+#include "events/event_queue.hpp"
+#include "lua/property.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "ui/ui_events.hpp"
 
 namespace lua {
 
@@ -152,8 +152,8 @@ auto db_check_iterator(lua_State* L, int stack_pos) -> database::Iterator* {
   return it;
 }
 
-static auto push_iterator(lua_State* state, const database::Iterator& it)
-    -> void {
+static auto push_iterator(lua_State* state,
+                          const database::Iterator& it) -> void {
   database::Iterator** data = reinterpret_cast<database::Iterator**>(
       lua_newuserdata(state, sizeof(uintptr_t)));
   *data = new database::Iterator(it);
@@ -198,12 +198,10 @@ static auto db_iterator_gc(lua_State* state) -> int {
   return 0;
 }
 
-static const struct luaL_Reg kDbIteratorFuncs[] = {{"next", db_iterate},
-                                                   {"prev", db_iterate_prev},
-                                                   {"clone", db_iterator_clone},
-                                                   {"__call", db_iterate},
-                                                   {"__gc", db_iterator_gc},
-                                                   {NULL, NULL}};
+static const struct luaL_Reg kDbIteratorFuncs[] = {
+    {"next", db_iterate},         {"prev", db_iterate_prev},
+    {"clone", db_iterator_clone}, {"__call", db_iterate},
+    {"__gc", db_iterator_gc},     {NULL, NULL}};
 
 static auto record_text(lua_State* state) -> int {
   LuaRecord* data = reinterpret_cast<LuaRecord*>(
diff --git a/src/lua/include/lua_database.hpp b/src/tangara/lua/lua_database.hpp
index b0d2acbd..328004ef 100644
--- a/src/lua/include/lua_database.hpp
+++ b/src/tangara/lua/lua_database.hpp
@@ -8,7 +8,7 @@
 
 #include "lua.hpp"
 
-#include "database.hpp"
+#include "database/database.hpp"
 
 namespace lua {
 
diff --git a/src/lua/lua_filesystem.cpp b/src/tangara/lua/lua_filesystem.cpp
index f0dbaf9a..f0dbaf9a 100644
--- a/src/lua/lua_filesystem.cpp
+++ b/src/tangara/lua/lua_filesystem.cpp
diff --git a/src/lua/include/lua_filesystem.hpp b/src/tangara/lua/lua_filesystem.hpp
index 2a829405..2a829405 100644
--- a/src/lua/include/lua_filesystem.hpp
+++ b/src/tangara/lua/lua_filesystem.hpp
diff --git a/src/lua/lua_queue.cpp b/src/tangara/lua/lua_queue.cpp
index dfb820c2..bc393aa5 100644
--- a/src/lua/lua_queue.cpp
+++ b/src/tangara/lua/lua_queue.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "lua_database.hpp"
+#include "lua/lua_database.hpp"
 
 #include <memory>
 #include <string>
@@ -16,15 +16,15 @@
 #include "lua.h"
 #include "lvgl.h"
 
-#include "bridge.hpp"
-#include "database.hpp"
-#include "event_queue.hpp"
-#include "index.hpp"
-#include "property.hpp"
-#include "service_locator.hpp"
-#include "track.hpp"
-#include "track_queue.hpp"
-#include "ui_events.hpp"
+#include "audio/track_queue.hpp"
+#include "database/database.hpp"
+#include "database/index.hpp"
+#include "database/track.hpp"
+#include "events/event_queue.hpp"
+#include "lua/bridge.hpp"
+#include "lua/property.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "ui/ui_events.hpp"
 
 namespace lua {
 
diff --git a/src/lua/include/lua_queue.hpp b/src/tangara/lua/lua_queue.hpp
index c5cfe04d..c5cfe04d 100644
--- a/src/lua/include/lua_queue.hpp
+++ b/src/tangara/lua/lua_queue.hpp
diff --git a/src/lua/include/lua_registry.hpp b/src/tangara/lua/lua_registry.hpp
index abc5063e..e556b6eb 100644
--- a/src/lua/include/lua_registry.hpp
+++ b/src/tangara/lua/lua_registry.hpp
@@ -11,9 +11,9 @@
 
 #include "lua.hpp"
 
-#include "bridge.hpp"
-#include "lua_thread.hpp"
-#include "service_locator.hpp"
+#include "lua/bridge.hpp"
+#include "lua/lua_thread.hpp"
+#include "system_fsm/service_locator.hpp"
 
 namespace lua {
 
diff --git a/src/lua/lua_screen.cpp b/src/tangara/lua/lua_screen.cpp
index f17f6b1a..8d87eebd 100644
--- a/src/lua/lua_screen.cpp
+++ b/src/tangara/lua/lua_screen.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "lua_screen.hpp"
+#include "lua/lua_screen.hpp"
 
 #include <memory>
 #include <string>
@@ -16,15 +16,15 @@
 #include "lua.h"
 #include "lvgl.h"
 
-#include "bridge.hpp"
-#include "database.hpp"
-#include "event_queue.hpp"
-#include "index.hpp"
-#include "property.hpp"
-#include "service_locator.hpp"
-#include "track.hpp"
-#include "track_queue.hpp"
-#include "ui_events.hpp"
+#include "audio/track_queue.hpp"
+#include "database/database.hpp"
+#include "database/index.hpp"
+#include "database/track.hpp"
+#include "events/event_queue.hpp"
+#include "lua/bridge.hpp"
+#include "lua/property.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "ui/ui_events.hpp"
 
 namespace lua {
 
diff --git a/src/lua/include/lua_screen.hpp b/src/tangara/lua/lua_screen.hpp
index 1c3bed1a..1c3bed1a 100644
--- a/src/lua/include/lua_screen.hpp
+++ b/src/tangara/lua/lua_screen.hpp
diff --git a/src/lua/lua_theme.cpp b/src/tangara/lua/lua_theme.cpp
index 72434d97..5edde104 100644
--- a/src/lua/lua_theme.cpp
+++ b/src/tangara/lua/lua_theme.cpp
@@ -5,20 +5,20 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "lua_version.hpp"
+#include "lua/lua_version.hpp"
 
 #include <string>
 
-#include "bridge.hpp"
 #include "lua.hpp"
+#include "lua/bridge.hpp"
 
 #include "esp_app_desc.h"
 #include "esp_log.h"
 #include "lauxlib.h"
 #include "lua.h"
-#include "lua_thread.hpp"
+#include "lua/lua_thread.hpp"
 #include "luavgl.h"
-#include "themes.hpp"
+#include "ui/themes.hpp"
 
 namespace lua {
 
@@ -35,7 +35,7 @@ static auto set_style(lua_State* L) -> int {
 static auto set_theme(lua_State* L) -> int {
   std::string class_name;
   luaL_checktype(L, -1, LUA_TTABLE);
-  lua_pushnil(L);  /* first key */
+  lua_pushnil(L); /* first key */
   while (lua_next(L, -2) != 0) {
     /* uses 'key' (at index -2) and 'value' (at index -1) */
     if (lua_type(L, -2) == LUA_TSTRING) {
@@ -43,11 +43,11 @@ static auto set_theme(lua_State* L) -> int {
     }
     if (lua_type(L, -1) == LUA_TTABLE) {
       // Nesting
-      lua_pushnil(L); // First key
+      lua_pushnil(L);  // First key
       while (lua_next(L, -2) != 0) {
         // Nesting the second
         int selector = -1;
-        lua_pushnil(L); // First key
+        lua_pushnil(L);  // First key
         while (lua_next(L, -2) != 0) {
           int idx = lua_tointeger(L, -2);
           if (idx == 1) {
@@ -60,12 +60,13 @@ static auto set_theme(lua_State* L) -> int {
               ESP_LOGI("lua_theme", "Style was null or malformed");
               return 0;
             } else {
-              ui::themes::Theme::instance()->AddStyle(class_name, selector, style);
+              ui::themes::Theme::instance()->AddStyle(class_name, selector,
+                                                      style);
             }
           }
-          lua_pop(L, 1); 
+          lua_pop(L, 1);
         }
-        lua_pop(L, 1); 
+        lua_pop(L, 1);
       }
     }
     /* removes 'value'; keeps 'key' for next iteration */
@@ -74,7 +75,9 @@ static auto set_theme(lua_State* L) -> int {
   return 0;
 }
 
-static const struct luaL_Reg kThemeFuncs[] = {{"set", set_theme}, {"set_style", set_style}, {NULL, NULL}};
+static const struct luaL_Reg kThemeFuncs[] = {{"set", set_theme},
+                                              {"set_style", set_style},
+                                              {NULL, NULL}};
 
 static auto lua_theme(lua_State* L) -> int {
   luaL_newlib(L, kThemeFuncs);
diff --git a/src/lua/include/lua_theme.hpp b/src/tangara/lua/lua_theme.hpp
index fed710e0..fed710e0 100644
--- a/src/lua/include/lua_theme.hpp
+++ b/src/tangara/lua/lua_theme.hpp
diff --git a/src/lua/lua_thread.cpp b/src/tangara/lua/lua_thread.cpp
index dd72e41d..77a46b45 100644
--- a/src/lua/lua_thread.cpp
+++ b/src/tangara/lua/lua_thread.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "lua_thread.hpp"
+#include "lua/lua_thread.hpp"
 
 #include <iostream>
 #include <memory>
@@ -13,11 +13,11 @@
 #include "esp_log.h"
 #include "lua.hpp"
 
-#include "bridge.hpp"
-#include "event_queue.hpp"
+#include "events/event_queue.hpp"
+#include "lua/bridge.hpp"
 #include "memory_resource.hpp"
-#include "service_locator.hpp"
-#include "ui_events.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "ui/ui_events.hpp"
 
 namespace lua {
 
@@ -42,8 +42,10 @@ class Allocator {
   size_t total_allocated_;
 };
 
-static auto lua_alloc(void* ud, void* ptr, size_t osize, size_t nsize)
-    -> void* {
+static auto lua_alloc(void* ud,
+                      void* ptr,
+                      size_t osize,
+                      size_t nsize) -> void* {
   Allocator* instance = reinterpret_cast<Allocator*>(ud);
   return instance->alloc(ptr, osize, nsize);
 }
diff --git a/src/lua/include/lua_thread.hpp b/src/tangara/lua/lua_thread.hpp
index 384de61d..d7602c1e 100644
--- a/src/lua/include/lua_thread.hpp
+++ b/src/tangara/lua/lua_thread.hpp
@@ -11,7 +11,7 @@
 
 #include "lua.hpp"
 
-#include "service_locator.hpp"
+#include "system_fsm/service_locator.hpp"
 
 namespace lua {
 
diff --git a/src/lua/lua_version.cpp b/src/tangara/lua/lua_version.cpp
index e5f06bb5..b85a30a5 100644
--- a/src/lua/lua_version.cpp
+++ b/src/tangara/lua/lua_version.cpp
@@ -5,18 +5,18 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "lua_version.hpp"
+#include "lua/lua_version.hpp"
 
 #include <string>
 
-#include "bridge.hpp"
 #include "lua.hpp"
+#include "lua/bridge.hpp"
 
 #include "esp_app_desc.h"
 #include "esp_log.h"
 #include "lauxlib.h"
 #include "lua.h"
-#include "lua_thread.hpp"
+#include "lua/lua_thread.hpp"
 
 namespace lua {
 
diff --git a/src/lua/include/lua_version.hpp b/src/tangara/lua/lua_version.hpp
index 4ba4be94..4ba4be94 100644
--- a/src/lua/include/lua_version.hpp
+++ b/src/tangara/lua/lua_version.hpp
diff --git a/src/lua/property.cpp b/src/tangara/lua/property.cpp
index 634a6a26..2b93809d 100644
--- a/src/lua/property.cpp
+++ b/src/tangara/lua/property.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "property.hpp"
+#include "lua/property.hpp"
 #include <sys/_stdint.h>
 
 #include <cmath>
@@ -14,15 +14,15 @@
 #include <string>
 #include <variant>
 
-#include "bluetooth_types.hpp"
+#include "database/track.hpp"
+#include "drivers/bluetooth_types.hpp"
 #include "lauxlib.h"
 #include "lua.h"
 #include "lua.hpp"
-#include "lua_thread.hpp"
+#include "lua/lua_thread.hpp"
 #include "lvgl.h"
 #include "memory_resource.hpp"
-#include "service_locator.hpp"
-#include "track.hpp"
+#include "system_fsm/service_locator.hpp"
 #include "types.hpp"
 
 namespace lua {
@@ -247,7 +247,7 @@ static auto pushTagValue(lua_State* L, const database::TagValue& val) -> void {
         if constexpr (std::is_same_v<T, std::pmr::string>) {
           lua_pushlstring(L, arg.data(), arg.size());
         } else if constexpr (std::is_same_v<
-                                 T, cpp::span<const std::pmr::string>>) {
+                                 T, std::span<const std::pmr::string>>) {
           lua_createtable(L, 0, arg.size());
           for (const auto& i : arg) {
             lua_pushlstring(L, i.data(), i.size());
diff --git a/src/lua/include/property.hpp b/src/tangara/lua/property.hpp
index 724261be..9f925766 100644
--- a/src/lua/include/property.hpp
+++ b/src/tangara/lua/property.hpp
@@ -10,11 +10,11 @@
 #include <memory>
 #include <string>
 
-#include "audio_events.hpp"
-#include "bluetooth_types.hpp"
+#include "audio/audio_events.hpp"
+#include "drivers/bluetooth_types.hpp"
 #include "lua.hpp"
 #include "lvgl.h"
-#include "service_locator.hpp"
+#include "system_fsm/service_locator.hpp"
 
 namespace lua {
 
diff --git a/src/lua/registry.cpp b/src/tangara/lua/registry.cpp
index a6487858..d33594a3 100644
--- a/src/lua/registry.cpp
+++ b/src/tangara/lua/registry.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "lua_registry.hpp"
+#include "lua/lua_registry.hpp"
 
 #include <iostream>
 #include <memory>
@@ -13,11 +13,11 @@
 #include "esp_log.h"
 #include "lua.hpp"
 
-#include "bridge.hpp"
-#include "event_queue.hpp"
+#include "events/event_queue.hpp"
+#include "lua/bridge.hpp"
 #include "memory_resource.hpp"
-#include "service_locator.hpp"
-#include "ui_events.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "ui/ui_events.hpp"
 
 namespace lua {
 
diff --git a/src/system_fsm/booting.cpp b/src/tangara/system_fsm/booting.cpp
index 44700cc4..58f14706 100644
--- a/src/system_fsm/booting.cpp
+++ b/src/tangara/system_fsm/booting.cpp
@@ -5,9 +5,9 @@
  */
 
 #include "collation.hpp"
-#include "haptics.hpp"
-#include "spiffs.hpp"
-#include "system_fsm.hpp"
+#include "drivers/haptics.hpp"
+#include "drivers/spiffs.hpp"
+#include "system_fsm/system_fsm.hpp"
 
 #include <stdint.h>
 #include <memory>
@@ -20,25 +20,25 @@
 #include "freertos/projdefs.h"
 #include "freertos/timers.h"
 
-#include "adc.hpp"
-#include "audio_fsm.hpp"
-#include "battery.hpp"
-#include "bluetooth.hpp"
-#include "bluetooth_types.hpp"
-#include "display_init.hpp"
-#include "event_queue.hpp"
-#include "gpios.hpp"
-#include "i2c.hpp"
-#include "nvs.hpp"
-#include "samd.hpp"
-#include "service_locator.hpp"
-#include "spi.hpp"
-#include "system_events.hpp"
-#include "tag_parser.hpp"
+#include "audio/audio_fsm.hpp"
+#include "audio/track_queue.hpp"
+#include "battery/battery.hpp"
+#include "database/tag_parser.hpp"
+#include "drivers/adc.hpp"
+#include "drivers/bluetooth.hpp"
+#include "drivers/bluetooth_types.hpp"
+#include "drivers/display_init.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/i2c.hpp"
+#include "drivers/nvs.hpp"
+#include "drivers/samd.hpp"
+#include "drivers/spi.hpp"
+#include "drivers/touchwheel.hpp"
+#include "events/event_queue.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "system_fsm/system_events.hpp"
 #include "tasks.hpp"
-#include "touchwheel.hpp"
-#include "track_queue.hpp"
-#include "ui_fsm.hpp"
+#include "ui/ui_fsm.hpp"
 
 namespace system_fsm {
 namespace states {
diff --git a/src/system_fsm/idle.cpp b/src/tangara/system_fsm/idle.cpp
index e28864b3..e499693d 100644
--- a/src/system_fsm/idle.cpp
+++ b/src/tangara/system_fsm/idle.cpp
@@ -4,20 +4,20 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "app_console.hpp"
-#include "file_gatherer.hpp"
+#include "app_console/app_console.hpp"
+#include "database/file_gatherer.hpp"
+#include "drivers/gpios.hpp"
 #include "freertos/portmacro.h"
 #include "freertos/projdefs.h"
-#include "gpios.hpp"
 #include "result.hpp"
 
-#include "audio_fsm.hpp"
-#include "event_queue.hpp"
-#include "samd.hpp"
-#include "storage.hpp"
-#include "system_events.hpp"
-#include "system_fsm.hpp"
-#include "ui_fsm.hpp"
+#include "audio/audio_fsm.hpp"
+#include "drivers/samd.hpp"
+#include "drivers/storage.hpp"
+#include "events/event_queue.hpp"
+#include "system_fsm/system_events.hpp"
+#include "system_fsm/system_fsm.hpp"
+#include "ui/ui_fsm.hpp"
 
 namespace system_fsm {
 namespace states {
diff --git a/src/system_fsm/running.cpp b/src/tangara/system_fsm/running.cpp
index 796c96dc..ac36ec64 100644
--- a/src/system_fsm/running.cpp
+++ b/src/tangara/system_fsm/running.cpp
@@ -4,23 +4,24 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "app_console.hpp"
-#include "audio_events.hpp"
-#include "database.hpp"
-#include "db_events.hpp"
+#include "app_console/app_console.hpp"
+#include "audio/audio_events.hpp"
+#include "database/database.hpp"
+#include "database/db_events.hpp"
+#include "database/file_gatherer.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/spi.hpp"
 #include "ff.h"
-#include "file_gatherer.hpp"
 #include "freertos/portmacro.h"
 #include "freertos/projdefs.h"
-#include "gpios.hpp"
 #include "result.hpp"
 
-#include "audio_fsm.hpp"
-#include "event_queue.hpp"
-#include "storage.hpp"
-#include "system_events.hpp"
-#include "system_fsm.hpp"
-#include "ui_fsm.hpp"
+#include "audio/audio_fsm.hpp"
+#include "drivers/storage.hpp"
+#include "events/event_queue.hpp"
+#include "system_fsm/system_events.hpp"
+#include "system_fsm/system_fsm.hpp"
+#include "ui/ui_fsm.hpp"
 
 namespace system_fsm {
 namespace states {
@@ -42,11 +43,7 @@ void Running::entry() {
     sUnmountTimer = xTimerCreate("unmount_timeout", kTicksBeforeUnmount, false,
                                  NULL, timer_callback);
   }
-  // Only mount our storage immediately if we know it's not currently in use
-  // by the SAMD.
-  if (!sServices->samd().UsbMassStorage()) {
-    mountStorage();
-  }
+  mountStorage();
 }
 
 void Running::exit() {
@@ -80,10 +77,28 @@ void Running::react(const SdDetectChanged& ev) {
   if (ev.has_sd_card && !sStorage) {
     mountStorage();
   }
+
   // Don't automatically unmount, since this event seems to occasionally happen
   // supriously. FIXME: Why?
-  // (It doesn't matter too much; by the time we get this event the SD card has
-  // already been disconnected electrically.)
+  // Instead, check whether or not the card has actually gone away.
+  if (sStorage) {
+    FRESULT res;
+    FF_DIR dir;
+    {
+      auto lock = drivers::acquire_spi();
+      res = f_opendir(&dir, "/");
+    }
+
+    if (res != FR_OK) {
+      ESP_LOGW(kTag, "sd card ejected unsafely!");
+      unmountStorage();
+    }
+
+    {
+      auto lock = drivers::acquire_spi();
+      f_closedir(&dir);
+    }
+  }
 }
 
 void Running::react(const SamdUsbMscChanged& ev) {
@@ -134,25 +149,37 @@ auto Running::checkIdle() -> void {
   }
 }
 
-auto Running::mountStorage() -> bool {
+auto Running::updateSdState(drivers::SdState state) -> void {
+  sServices->sd(state);
+  events::Ui().Dispatch(SdStateChanged{});
+  events::Audio().Dispatch(SdStateChanged{});
+  events::System().Dispatch(SdStateChanged{});
+}
+
+auto Running::mountStorage() -> void {
+  // Only mount our storage if we know it's not currently in use by the SAMD.
+  if (sServices->samd().UsbMassStorage()) {
+    updateSdState(drivers::SdState::kNotMounted);
+    return;
+  }
+
   ESP_LOGI(kTag, "mounting sd card");
   auto storage_res = drivers::SdStorage::Create(sServices->gpios());
   if (storage_res.has_error()) {
     ESP_LOGW(kTag, "failed to mount!");
     switch (storage_res.error()) {
       case drivers::SdStorage::FAILED_TO_MOUNT:
-        sServices->sd(drivers::SdState::kNotFormatted);
+        updateSdState(drivers::SdState::kNotFormatted);
         break;
       case drivers::SdStorage::FAILED_TO_READ:
       default:
-        sServices->sd(drivers::SdState::kNotPresent);
+        updateSdState(drivers::SdState::kNotPresent);
         break;
     }
-    return false;
+    return;
   }
 
   sStorage.reset(storage_res.value());
-  sServices->sd(drivers::SdState::kMounted);
 
   ESP_LOGI(kTag, "opening database");
   sFileGatherer = new database::FileGathererImpl();
@@ -161,16 +188,14 @@ auto Running::mountStorage() -> bool {
                                sServices->collator(), sServices->bg_worker());
   if (database_res.has_error()) {
     unmountStorage();
-    return false;
+    return;
   }
 
   sServices->database(
       std::unique_ptr<database::Database>{database_res.value()});
 
   ESP_LOGI(kTag, "storage loaded okay");
-  events::Ui().Dispatch(StorageMounted{});
-  events::Audio().Dispatch(StorageMounted{});
-  events::System().Dispatch(StorageMounted{});
+  updateSdState(drivers::SdState::kMounted);
 
   // Tell the database to refresh so that we pick up any changes from the newly
   // mounted card.
@@ -183,14 +208,13 @@ auto Running::mountStorage() -> bool {
       db->updateIndexes();
     });
   }
-
-  return true;
 }
 
 auto Running::unmountStorage() -> void {
   ESP_LOGW(kTag, "unmounting storage");
   sServices->database({});
   sStorage.reset();
+  updateSdState(drivers::SdState::kNotMounted);
 }
 
 }  // namespace states
diff --git a/src/system_fsm/service_locator.cpp b/src/tangara/system_fsm/service_locator.cpp
index d8dcf44a..ef719930 100644
--- a/src/system_fsm/service_locator.cpp
+++ b/src/tangara/system_fsm/service_locator.cpp
@@ -4,13 +4,13 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "service_locator.hpp"
+#include "system_fsm/service_locator.hpp"
 
 #include <memory>
 
-#include "nvs.hpp"
-#include "storage.hpp"
-#include "touchwheel.hpp"
+#include "drivers/nvs.hpp"
+#include "drivers/storage.hpp"
+#include "drivers/touchwheel.hpp"
 
 namespace system_fsm {
 
diff --git a/src/system_fsm/include/service_locator.hpp b/src/tangara/system_fsm/service_locator.hpp
index 5978578c..5b2205eb 100644
--- a/src/system_fsm/include/service_locator.hpp
+++ b/src/tangara/system_fsm/service_locator.hpp
@@ -8,19 +8,19 @@
 
 #include <memory>
 
-#include "battery.hpp"
-#include "bluetooth.hpp"
+#include "audio/track_queue.hpp"
+#include "battery/battery.hpp"
+#include "drivers/bluetooth.hpp"
 #include "collation.hpp"
-#include "database.hpp"
-#include "gpios.hpp"
-#include "haptics.hpp"
-#include "nvs.hpp"
-#include "samd.hpp"
-#include "storage.hpp"
-#include "tag_parser.hpp"
+#include "database/database.hpp"
+#include "database/tag_parser.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/haptics.hpp"
+#include "drivers/nvs.hpp"
+#include "drivers/samd.hpp"
+#include "drivers/storage.hpp"
 #include "tasks.hpp"
-#include "touchwheel.hpp"
-#include "track_queue.hpp"
+#include "drivers/touchwheel.hpp"
 
 namespace system_fsm {
 
diff --git a/src/system_fsm/include/system_events.hpp b/src/tangara/system_fsm/system_events.hpp
index 22e3b6bd..3452e58e 100644
--- a/src/system_fsm/include/system_events.hpp
+++ b/src/tangara/system_fsm/system_events.hpp
@@ -8,13 +8,14 @@
 
 #include <memory>
 
-#include "battery.hpp"
-#include "bluetooth_types.hpp"
-#include "database.hpp"
+#include "battery/battery.hpp"
+#include "database/database.hpp"
+#include "drivers/bluetooth_types.hpp"
+#include "drivers/haptics.hpp"
+#include "drivers/samd.hpp"
+#include "drivers/storage.hpp"
 #include "ff.h"
-#include "haptics.hpp"
-#include "samd.hpp"
-#include "service_locator.hpp"
+#include "system_fsm/service_locator.hpp"
 #include "tinyfsm.hpp"
 
 namespace system_fsm {
@@ -38,10 +39,7 @@ struct FatalError : tinyfsm::Event {};
 
 struct OnIdle : tinyfsm::Event {};
 
-/*
- * Sent by SysState when the system storage has been successfully mounted.
- */
-struct StorageMounted : tinyfsm::Event {};
+struct SdStateChanged : tinyfsm::Event {};
 
 struct StorageError : tinyfsm::Event {
   FRESULT error;
diff --git a/src/system_fsm/system_fsm.cpp b/src/tangara/system_fsm/system_fsm.cpp
index 59d41c73..2e819569 100644
--- a/src/system_fsm/system_fsm.cpp
+++ b/src/tangara/system_fsm/system_fsm.cpp
@@ -4,15 +4,15 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "system_fsm.hpp"
-#include "audio_fsm.hpp"
+#include "system_fsm/system_fsm.hpp"
+#include "audio/audio_fsm.hpp"
+#include "audio/track_queue.hpp"
+#include "database/tag_parser.hpp"
 #include "driver/gpio.h"
-#include "event_queue.hpp"
-#include "gpios.hpp"
-#include "service_locator.hpp"
-#include "system_events.hpp"
-#include "tag_parser.hpp"
-#include "track_queue.hpp"
+#include "drivers/gpios.hpp"
+#include "events/event_queue.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "system_fsm/system_events.hpp"
 
 [[maybe_unused]] static const char kTag[] = "system";
 
diff --git a/src/system_fsm/include/system_fsm.hpp b/src/tangara/system_fsm/system_fsm.hpp
index f01afb3f..5c4157cd 100644
--- a/src/system_fsm/include/system_fsm.hpp
+++ b/src/tangara/system_fsm/system_fsm.hpp
@@ -8,27 +8,26 @@
 
 #include <memory>
 
-#include "app_console.hpp"
-#include "audio_events.hpp"
-#include "battery.hpp"
-#include "bluetooth.hpp"
-#include "database.hpp"
-#include "db_events.hpp"
-#include "display.hpp"
-#include "gpios.hpp"
-#include "nvs.hpp"
-#include "samd.hpp"
-#include "service_locator.hpp"
-#include "storage.hpp"
-#include "tag_parser.hpp"
-#include "tinyfsm.hpp"
-#include "touchwheel.hpp"
-
 #include "freertos/FreeRTOS.h"
 #include "freertos/timers.h"
 
-#include "system_events.hpp"
-#include "track_queue.hpp"
+#include "app_console/app_console.hpp"
+#include "audio/audio_events.hpp"
+#include "audio/track_queue.hpp"
+#include "battery/battery.hpp"
+#include "database/database.hpp"
+#include "database/db_events.hpp"
+#include "database/tag_parser.hpp"
+#include "drivers/bluetooth.hpp"
+#include "drivers/display.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/nvs.hpp"
+#include "drivers/samd.hpp"
+#include "drivers/storage.hpp"
+#include "drivers/touchwheel.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "system_fsm/system_events.hpp"
+#include "tinyfsm.hpp"
 
 namespace system_fsm {
 
@@ -56,7 +55,6 @@ class SystemState : public tinyfsm::Fsm<SystemState> {
 
   virtual void react(const DisplayReady&) {}
   virtual void react(const BootComplete&) {}
-  virtual void react(const StorageMounted&) {}
   virtual void react(const StorageError&) {}
   virtual void react(const KeyLockChanged&) {}
   virtual void react(const SdDetectChanged&) {}
@@ -111,7 +109,8 @@ class Running : public SystemState {
  private:
   auto checkIdle() -> void;
 
-  auto mountStorage() -> bool;
+  auto updateSdState(drivers::SdState) -> void;
+  auto mountStorage() -> void;
   auto unmountStorage() -> void;
 
   bool storage_mounted_;
diff --git a/src/ui/include/fonts.hpp b/src/tangara/ui/fonts.hpp
index e4a8e139..e4a8e139 100644
--- a/src/ui/include/fonts.hpp
+++ b/src/tangara/ui/fonts.hpp
diff --git a/src/ui/lvgl_task.cpp b/src/tangara/ui/lvgl_task.cpp
index 51da0179..448aa261 100644
--- a/src/ui/lvgl_task.cpp
+++ b/src/tangara/ui/lvgl_task.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "lvgl_task.hpp"
+#include "ui/lvgl_task.hpp"
 
 #include <dirent.h>
 #include <stdint.h>
@@ -20,8 +20,9 @@
 #include "core/lv_obj.h"
 #include "core/lv_obj_pos.h"
 #include "core/lv_obj_tree.h"
+#include "drivers/touchwheel.hpp"
 #include "esp_log.h"
-#include "event_queue.hpp"
+#include "events/event_queue.hpp"
 #include "extra/themes/basic/lv_theme_basic.h"
 #include "font/lv_font.h"
 #include "freertos/portmacro.h"
@@ -30,21 +31,20 @@
 #include "hal/gpio_types.h"
 #include "hal/lv_hal_indev.h"
 #include "hal/spi_types.h"
+#include "input/lvgl_input_driver.hpp"
 #include "lua.h"
 #include "lv_api_map.h"
 #include "lvgl/lvgl.h"
-#include "lvgl_input_driver.hpp"
 #include "misc/lv_color.h"
 #include "misc/lv_style.h"
 #include "misc/lv_timer.h"
-#include "modal.hpp"
 #include "tasks.hpp"
-#include "touchwheel.hpp"
-#include "ui_fsm.hpp"
+#include "ui/modal.hpp"
+#include "ui/ui_fsm.hpp"
 #include "widgets/lv_label.h"
 
-#include "display.hpp"
-#include "gpios.hpp"
+#include "drivers/display.hpp"
+#include "drivers/gpios.hpp"
 
 namespace ui {
 
diff --git a/src/ui/include/lvgl_task.hpp b/src/tangara/ui/lvgl_task.hpp
index 8efcbf35..fcf00ab1 100644
--- a/src/ui/include/lvgl_task.hpp
+++ b/src/tangara/ui/lvgl_task.hpp
@@ -14,11 +14,11 @@
 #include "freertos/task.h"
 #include "freertos/timers.h"
 
-#include "display.hpp"
-#include "lvgl_input_driver.hpp"
-#include "screen.hpp"
-#include "themes.hpp"
-#include "touchwheel.hpp"
+#include "drivers/display.hpp"
+#include "input/lvgl_input_driver.hpp"
+#include "drivers/touchwheel.hpp"
+#include "ui/screen.hpp"
+#include "ui/themes.hpp"
 
 namespace ui {
 
diff --git a/src/ui/modal.cpp b/src/tangara/ui/modal.cpp
index ec541914..4f5a2432 100644
--- a/src/ui/modal.cpp
+++ b/src/tangara/ui/modal.cpp
@@ -5,7 +5,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "modal.hpp"
+#include "ui/modal.hpp"
 
 #include "misc/lv_color.h"
 
@@ -14,17 +14,17 @@
 
 #include "core/lv_group.h"
 #include "core/lv_obj_pos.h"
-#include "event_queue.hpp"
+#include "database/index.hpp"
+#include "events/event_queue.hpp"
 #include "extra/widgets/list/lv_list.h"
 #include "extra/widgets/menu/lv_menu.h"
 #include "extra/widgets/spinner/lv_spinner.h"
 #include "hal/lv_hal_disp.h"
-#include "index.hpp"
 #include "misc/lv_area.h"
-#include "screen.hpp"
-#include "themes.hpp"
-#include "ui_events.hpp"
-#include "ui_fsm.hpp"
+#include "ui/screen.hpp"
+#include "ui/themes.hpp"
+#include "ui/ui_events.hpp"
+#include "ui/ui_fsm.hpp"
 #include "widgets/lv_label.h"
 
 namespace ui {
diff --git a/src/ui/include/modal.hpp b/src/tangara/ui/modal.hpp
index 6b7e792e..bd5209a7 100644
--- a/src/ui/include/modal.hpp
+++ b/src/tangara/ui/modal.hpp
@@ -13,7 +13,7 @@
 #include "core/lv_obj_tree.h"
 #include "lvgl.h"
 
-#include "screen.hpp"
+#include "ui/screen.hpp"
 
 namespace ui {
 
diff --git a/src/ui/screen.cpp b/src/tangara/ui/screen.cpp
index a39aaf7e..8357cfbd 100644
--- a/src/ui/screen.cpp
+++ b/src/tangara/ui/screen.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "screen.hpp"
+#include "ui/screen.hpp"
 
 #include <memory>
 
diff --git a/src/ui/include/screen.hpp b/src/tangara/ui/screen.hpp
index 40284fda..40284fda 100644
--- a/src/ui/include/screen.hpp
+++ b/src/tangara/ui/screen.hpp
diff --git a/src/ui/screen_lua.cpp b/src/tangara/ui/screen_lua.cpp
index 685e43cb..c6cda7ae 100644
--- a/src/ui/screen_lua.cpp
+++ b/src/tangara/ui/screen_lua.cpp
@@ -4,15 +4,15 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "screen_lua.hpp"
+#include "ui/screen_lua.hpp"
 
 #include "core/lv_obj_tree.h"
 #include "lua.h"
 #include "lua.hpp"
-#include "property.hpp"
-#include "themes.hpp"
+#include "lua/property.hpp"
+#include "ui/themes.hpp"
 
-#include "lua_thread.hpp"
+#include "lua/lua_thread.hpp"
 #include "luavgl.h"
 
 namespace ui {
diff --git a/src/ui/include/screen_lua.hpp b/src/tangara/ui/screen_lua.hpp
index 8a463bad..d6bc20a2 100644
--- a/src/ui/include/screen_lua.hpp
+++ b/src/tangara/ui/screen_lua.hpp
@@ -8,8 +8,8 @@
 
 #include "lua.hpp"
 
-#include "property.hpp"
-#include "screen.hpp"
+#include "lua/property.hpp"
+#include "ui/screen.hpp"
 
 namespace ui {
 namespace screens {
diff --git a/src/ui/screen_splash.cpp b/src/tangara/ui/screen_splash.cpp
index 48cfef88..651f00dd 100644
--- a/src/ui/screen_splash.cpp
+++ b/src/tangara/ui/screen_splash.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "screen_splash.hpp"
+#include "ui/screen_splash.hpp"
 
 #include "core/lv_obj.h"
 #include "core/lv_obj_style.h"
diff --git a/src/ui/include/screen_splash.hpp b/src/tangara/ui/screen_splash.hpp
index 6e746345..e56c915f 100644
--- a/src/ui/include/screen_splash.hpp
+++ b/src/tangara/ui/screen_splash.hpp
@@ -10,7 +10,7 @@
 
 #include "lvgl.h"
 
-#include "screen.hpp"
+#include "ui/screen.hpp"
 
 namespace ui {
 namespace screens {
diff --git a/src/ui/themes.cpp b/src/tangara/ui/themes.cpp
index b13f226a..44638c55 100644
--- a/src/ui/themes.cpp
+++ b/src/tangara/ui/themes.cpp
@@ -1,4 +1,4 @@
-#include "themes.hpp"
+#include "ui/themes.hpp"
 #include "core/lv_obj.h"
 #include "core/lv_obj_style.h"
 #include "core/lv_obj_tree.h"
@@ -35,9 +35,9 @@ void Theme::Apply(void) {
 void Theme::Callback(lv_obj_t* obj) {
   // Find and apply base styles
   if (auto search = style_map.find("base"); search != style_map.end()) {
-      for (const auto& pair : search->second) {
-        lv_obj_add_style(obj, pair.second, pair.first);
-      }
+    for (const auto& pair : search->second) {
+      lv_obj_add_style(obj, pair.second, pair.first);
+    }
   }
 
   // Determine class name
@@ -60,19 +60,18 @@ void Theme::Callback(lv_obj_t* obj) {
 
   // Apply all styles from class
   if (auto search = style_map.find(class_name); search != style_map.end()) {
-      for (const auto& pair : search->second) {
-        lv_obj_add_style(obj, pair.second, pair.first);
-      }
+    for (const auto& pair : search->second) {
+      lv_obj_add_style(obj, pair.second, pair.first);
+    }
   }
-
 }
 
 void Theme::ApplyStyle(lv_obj_t* obj, std::string style_key) {
   if (auto search = style_map.find(style_key); search != style_map.end()) {
-      for (const auto& pair : search->second) {
-        lv_obj_remove_style(obj, pair.second, pair.first);
-        lv_obj_add_style(obj, pair.second, pair.first);
-      }
+    for (const auto& pair : search->second) {
+      lv_obj_remove_style(obj, pair.second, pair.first);
+      lv_obj_add_style(obj, pair.second, pair.first);
+    }
   }
 }
 
@@ -85,7 +84,7 @@ void Theme::AddStyle(std::string key, int selector, lv_style_t* style) {
   style_map.try_emplace(key, std::vector<std::pair<int, lv_style_t*>>{});
   if (auto search = style_map.find(key); search != style_map.end()) {
     // Key exists
-    auto &vec = search->second;
+    auto& vec = search->second;
     // Add it to the list
     vec.push_back(std::make_pair(selector, style));
   }
diff --git a/src/ui/include/themes.hpp b/src/tangara/ui/themes.hpp
index 09b9cdce..fd576478 100644
--- a/src/ui/include/themes.hpp
+++ b/src/tangara/ui/themes.hpp
@@ -1,7 +1,7 @@
 #pragma once
 
-#include <string>
 #include <map>
+#include <string>
 #include <vector>
 #include "lvgl.h"
 
@@ -32,7 +32,6 @@ class Theme {
   Theme();
   std::map<std::string, std::vector<std::pair<int, lv_style_t*>>> style_map;
   lv_theme_t theme_;
-
 };
 }  // namespace themes
 }  // namespace ui
diff --git a/src/ui/include/ui_events.hpp b/src/tangara/ui/ui_events.hpp
index 3d794edc..cb446cd2 100644
--- a/src/ui/include/ui_events.hpp
+++ b/src/tangara/ui/ui_events.hpp
@@ -7,12 +7,12 @@
 #pragma once
 
 #include <memory>
-#include "database.hpp"
-#include "gpios.hpp"
-#include "index.hpp"
-#include "nvs.hpp"
-#include "screen.hpp"
+#include "database/database.hpp"
+#include "database/index.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/nvs.hpp"
 #include "tinyfsm.hpp"
+#include "ui/screen.hpp"
 
 namespace ui {
 
diff --git a/src/ui/ui_fsm.cpp b/src/tangara/ui/ui_fsm.cpp
index 1cbf1be4..17d6c511 100644
--- a/src/ui/ui_fsm.cpp
+++ b/src/tangara/ui/ui_fsm.cpp
@@ -4,63 +4,63 @@
  * SPDX-License-Identifier: GPL-3.0-only
  */
 
-#include "ui_fsm.hpp"
+#include "ui/ui_fsm.hpp"
 
 #include <memory>
 #include <memory_resource>
 #include <variant>
 
-#include "bluetooth_types.hpp"
-#include "db_events.hpp"
-#include "device_factory.hpp"
-#include "display_init.hpp"
-#include "esp_spp_api.h"
-#include "feedback_haptics.hpp"
-#include "freertos/portmacro.h"
-#include "freertos/projdefs.h"
-#include "input_device.hpp"
-#include "input_touch_wheel.hpp"
-#include "input_volume_buttons.hpp"
-#include "lua.h"
-#include "lua.hpp"
+#include "FreeRTOSConfig.h"
+#include "lvgl.h"
 
-#include "audio_fsm.hpp"
-#include "battery.hpp"
 #include "core/lv_group.h"
 #include "core/lv_obj.h"
 #include "core/lv_obj_tree.h"
-#include "database.hpp"
 #include "esp_heap_caps.h"
+#include "esp_spp_api.h"
 #include "esp_timer.h"
-#include "haptics.hpp"
-#include "lauxlib.h"
-#include "lua_thread.hpp"
+#include "freertos/portmacro.h"
+#include "freertos/projdefs.h"
+#include "lua.hpp"
 #include "luavgl.h"
-#include "lvgl_input_driver.hpp"
-#include "memory_resource.hpp"
 #include "misc/lv_gc.h"
-
-#include "audio_events.hpp"
-#include "display.hpp"
-#include "event_queue.hpp"
-#include "gpios.hpp"
-#include "lua_registry.hpp"
-#include "lvgl_task.hpp"
-#include "nvs.hpp"
-#include "property.hpp"
-#include "samd.hpp"
-#include "screen.hpp"
-#include "screen_lua.hpp"
-#include "screen_splash.hpp"
-#include "spiffs.hpp"
-#include "storage.hpp"
-#include "system_events.hpp"
 #include "tinyfsm.hpp"
-#include "touchwheel.hpp"
-#include "track_queue.hpp"
-#include "ui_events.hpp"
 #include "widgets/lv_label.h"
 
+#include "audio/audio_events.hpp"
+#include "audio/audio_fsm.hpp"
+#include "audio/track_queue.hpp"
+#include "battery/battery.hpp"
+#include "database/database.hpp"
+#include "database/db_events.hpp"
+#include "drivers/bluetooth_types.hpp"
+#include "drivers/display.hpp"
+#include "drivers/display_init.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/haptics.hpp"
+#include "drivers/nvs.hpp"
+#include "drivers/samd.hpp"
+#include "drivers/spiffs.hpp"
+#include "drivers/storage.hpp"
+#include "drivers/touchwheel.hpp"
+#include "events/event_queue.hpp"
+#include "input/device_factory.hpp"
+#include "input/feedback_haptics.hpp"
+#include "input/input_device.hpp"
+#include "input/input_touch_wheel.hpp"
+#include "input/input_volume_buttons.hpp"
+#include "input/lvgl_input_driver.hpp"
+#include "lua/lua_registry.hpp"
+#include "lua/lua_thread.hpp"
+#include "lua/property.hpp"
+#include "memory_resource.hpp"
+#include "system_fsm/system_events.hpp"
+#include "ui/lvgl_task.hpp"
+#include "ui/screen.hpp"
+#include "ui/screen_lua.hpp"
+#include "ui/screen_splash.hpp"
+#include "ui/ui_events.hpp"
+
 namespace ui {
 
 [[maybe_unused]] static constexpr char kTag[] = "ui_fsm";
@@ -253,6 +253,8 @@ lua::Property UiState::sDatabaseAutoUpdate{
       return true;
     }};
 
+lua::Property UiState::sSdMounted{false};
+
 lua::Property UiState::sUsbMassStorageEnabled{
     false, [](const lua::LuaValue& val) {
       if (!std::holds_alternative<bool>(val)) {
@@ -334,6 +336,10 @@ void UiState::react(const system_fsm::SamdUsbStatusChanged& ev) {
                                 drivers::Samd::UsbStatus::kAttachedBusy);
 }
 
+void UiState::react(const system_fsm::SdStateChanged&) {
+  sSdMounted.setDirect(sServices->sd() == drivers::SdState::kMounted);
+}
+
 void UiState::react(const database::event::UpdateStarted&) {
   sDatabaseUpdating.setDirect(true);
 }
@@ -444,7 +450,8 @@ void Splash::react(const system_fsm::BootComplete& ev) {
   sTask->input(sInput);
 }
 
-void Splash::react(const system_fsm::StorageMounted&) {
+void Splash::react(const system_fsm::SdStateChanged& ev) {
+  UiState::react(ev);
   transit<Lua>();
 }
 
@@ -517,6 +524,7 @@ void Lua::entry() {
         {
             {"push", [&](lua_State* s) { return PushLuaScreen(s); }},
             {"pop", [&](lua_State* s) { return PopLuaScreen(s); }},
+            {"reset", [&](lua_State* s) { return ResetLuaScreen(s); }},
         });
     registry.AddPropertyModule(
         "alerts", {
@@ -533,6 +541,9 @@ void Lua::entry() {
                                    {"updating", &sDatabaseUpdating},
                                    {"auto_update", &sDatabaseAutoUpdate},
                                });
+    registry.AddPropertyModule("sd_card", {
+                                              {"mounted", &sSdMounted},
+                                          });
     registry.AddPropertyModule("usb",
                                {
                                    {"msc_enabled", &sUsbMassStorageEnabled},
@@ -547,7 +558,9 @@ void Lua::entry() {
     sBluetoothDevices.setDirect(bt.KnownDevices());
 
     sCurrentScreen.reset();
-    sLua->RunScript("/sdcard/config.lua");
+    if (sServices->sd() == drivers::SdState::kMounted) {
+      sLua->RunScript("/sdcard/config.lua");
+    }
     sLua->RunScript("/lua/main.lua");
   }
 }
@@ -587,16 +600,6 @@ auto Lua::PushLuaScreen(lua_State* s) -> int {
   return 0;
 }
 
-auto Lua::QueueNext(lua_State*) -> int {
-  sServices->track_queue().next();
-  return 0;
-}
-
-auto Lua::QueuePrevious(lua_State*) -> int {
-  sServices->track_queue().previous();
-  return 0;
-}
-
 auto Lua::PopLuaScreen(lua_State* s) -> int {
   if (!sCurrentScreen->canPop()) {
     return 0;
@@ -607,6 +610,30 @@ auto Lua::PopLuaScreen(lua_State* s) -> int {
   return 0;
 }
 
+auto Lua::ResetLuaScreen(lua_State* s) -> int {
+  if (sCurrentScreen) {
+    if (!sCurrentScreen->canPop()) {
+      ESP_LOGW(kTag, "ignoring reset as popping is blocked");
+      return 0;
+    }
+    sCurrentScreen->onHidden();
+  }
+  while (!sScreens.empty()) {
+    sScreens.pop();
+  }
+  return PushLuaScreen(s);
+}
+
+auto Lua::QueueNext(lua_State*) -> int {
+  sServices->track_queue().next();
+  return 0;
+}
+
+auto Lua::QueuePrevious(lua_State*) -> int {
+  sServices->track_queue().previous();
+  return 0;
+}
+
 auto Lua::Ticks(lua_State* s) -> int {
   lua_pushinteger(s, esp_timer_get_time() / 1000);
   return 1;
diff --git a/src/ui/include/ui_fsm.hpp b/src/tangara/ui/ui_fsm.hpp
index 325aea8f..af8d75fb 100644
--- a/src/ui/include/ui_fsm.hpp
+++ b/src/tangara/ui/ui_fsm.hpp
@@ -10,30 +10,31 @@
 #include <memory>
 #include <stack>
 
-#include "audio_events.hpp"
-#include "battery.hpp"
-#include "db_events.hpp"
-#include "device_factory.hpp"
-#include "display.hpp"
-#include "feedback_haptics.hpp"
-#include "gpios.hpp"
-#include "input_touch_wheel.hpp"
-#include "input_volume_buttons.hpp"
-#include "lua_thread.hpp"
-#include "lvgl_input_driver.hpp"
-#include "lvgl_task.hpp"
-#include "modal.hpp"
-#include "nvs.hpp"
-#include "property.hpp"
-#include "screen.hpp"
-#include "service_locator.hpp"
-#include "storage.hpp"
-#include "system_events.hpp"
 #include "tinyfsm.hpp"
-#include "touchwheel.hpp"
-#include "track.hpp"
-#include "track_queue.hpp"
-#include "ui_events.hpp"
+
+#include "audio/audio_events.hpp"
+#include "audio/track_queue.hpp"
+#include "battery/battery.hpp"
+#include "database/db_events.hpp"
+#include "database/track.hpp"
+#include "drivers/display.hpp"
+#include "drivers/gpios.hpp"
+#include "drivers/nvs.hpp"
+#include "drivers/storage.hpp"
+#include "drivers/touchwheel.hpp"
+#include "input/device_factory.hpp"
+#include "input/feedback_haptics.hpp"
+#include "input/input_touch_wheel.hpp"
+#include "input/input_volume_buttons.hpp"
+#include "input/lvgl_input_driver.hpp"
+#include "lua/lua_thread.hpp"
+#include "lua/property.hpp"
+#include "system_fsm/service_locator.hpp"
+#include "system_fsm/system_events.hpp"
+#include "ui/lvgl_task.hpp"
+#include "ui/modal.hpp"
+#include "ui/screen.hpp"
+#include "ui/ui_events.hpp"
 
 namespace ui {
 
@@ -57,7 +58,7 @@ class UiState : public tinyfsm::Fsm<UiState> {
   virtual void react(const DumpLuaStack&) {}
   virtual void react(const internal::BackPressed&) {}
   virtual void react(const system_fsm::BootComplete&) {}
-  virtual void react(const system_fsm::StorageMounted&) {}
+  virtual void react(const system_fsm::SdStateChanged&);
 
   void react(const system_fsm::BatteryStateChanged&);
   void react(const audio::PlaybackUpdate&);
@@ -136,6 +137,8 @@ class UiState : public tinyfsm::Fsm<UiState> {
   static lua::Property sDatabaseUpdating;
   static lua::Property sDatabaseAutoUpdate;
 
+  static lua::Property sSdMounted;
+
   static lua::Property sUsbMassStorageEnabled;
   static lua::Property sUsbMassStorageBusy;
 };
@@ -147,7 +150,7 @@ class Splash : public UiState {
   void exit() override;
 
   void react(const system_fsm::BootComplete&) override;
-  void react(const system_fsm::StorageMounted&) override;
+  void react(const system_fsm::SdStateChanged&) override;
 
   using UiState::react;
 };
@@ -166,6 +169,7 @@ class Lua : public UiState {
  private:
   auto PushLuaScreen(lua_State*) -> int;
   auto PopLuaScreen(lua_State*) -> int;
+  auto ResetLuaScreen(lua_State*) -> int;
 
   auto ShowAlert(lua_State*) -> int;
   auto HideAlert(lua_State*) -> int;
diff --git a/src/tasks/CMakeLists.txt b/src/tasks/CMakeLists.txt
index 0fdacf78..814c9943 100644
--- a/src/tasks/CMakeLists.txt
+++ b/src/tasks/CMakeLists.txt
@@ -1,5 +1,5 @@
 # Copyright 2023 jacqueline <me@jacqueline.id.au>
 #
 # SPDX-License-Identifier: GPL-3.0-only
-idf_component_register(SRCS "tasks.cpp" INCLUDE_DIRS "." REQUIRES "span" "memory")
+idf_component_register(SRCS "tasks.cpp" INCLUDE_DIRS "." REQUIRES "memory")
 target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/tasks/tasks.cpp b/src/tasks/tasks.cpp
index aa382655..d3937c68 100644
--- a/src/tasks/tasks.cpp
+++ b/src/tasks/tasks.cpp
@@ -33,12 +33,12 @@ auto Name<Type::kAudioConverter>() -> std::pmr::string {
 }
 
 template <Type t>
-auto AllocateStack() -> cpp::span<StackType_t>;
+auto AllocateStack() -> std::span<StackType_t>;
 
 // Decoders often require a very large amount of stack space, since they aren't
 // usually written with embedded use cases in mind.
 template <>
-auto AllocateStack<Type::kAudioDecoder>() -> cpp::span<StackType_t> {
+auto AllocateStack<Type::kAudioDecoder>() -> std::span<StackType_t> {
   constexpr std::size_t size = 20 * 1024;
   static StackType_t sStack[size];
   return {sStack, size};
@@ -46,14 +46,14 @@ auto AllocateStack<Type::kAudioDecoder>() -> cpp::span<StackType_t> {
 // LVGL requires only a relatively small stack. Lua's stack is allocated
 // separately.
 template <>
-auto AllocateStack<Type::kUi>() -> cpp::span<StackType_t> {
+auto AllocateStack<Type::kUi>() -> std::span<StackType_t> {
   constexpr std::size_t size = 14 * 1024;
   static StackType_t sStack[size];
   return {sStack, size};
 }
 template <>
 // PCM conversion and resampling uses a very small amount of stack.
-auto AllocateStack<Type::kAudioConverter>() -> cpp::span<StackType_t> {
+auto AllocateStack<Type::kAudioConverter>() -> std::span<StackType_t> {
   constexpr std::size_t size = 4 * 1024;
   static StackType_t sStack[size];
   return {sStack, size};
@@ -63,7 +63,7 @@ auto AllocateStack<Type::kAudioConverter>() -> cpp::span<StackType_t> {
 // cases, where large stack usage isn't so much of a concern. It therefore uses
 // an eye-wateringly large amount of stack.
 template <>
-auto AllocateStack<Type::kBackgroundWorker>() -> cpp::span<StackType_t> {
+auto AllocateStack<Type::kBackgroundWorker>() -> std::span<StackType_t> {
   std::size_t size = 64 * 1024;
   return {static_cast<StackType_t*>(heap_caps_malloc(size, MALLOC_CAP_SPIRAM)),
           size};
diff --git a/src/tasks/tasks.hpp b/src/tasks/tasks.hpp
index 47f26837..566b5706 100644
--- a/src/tasks/tasks.hpp
+++ b/src/tasks/tasks.hpp
@@ -11,6 +11,7 @@
 #include <future>
 #include <memory>
 #include <memory_resource>
+#include <span>
 #include <string>
 
 #include "esp_heap_caps.h"
@@ -19,7 +20,6 @@
 #include "freertos/projdefs.h"
 #include "freertos/queue.h"
 #include "freertos/task.h"
-#include "span.hpp"
 
 namespace tasks {
 
@@ -46,7 +46,7 @@ enum class Type {
 template <Type t>
 auto Name() -> std::pmr::string;
 template <Type t>
-auto AllocateStack() -> cpp::span<StackType_t>;
+auto AllocateStack() -> std::span<StackType_t>;
 template <Type t>
 auto Priority() -> UBaseType_t;
 
@@ -56,7 +56,7 @@ template <Type t>
 auto StartPersistent(const std::function<void(void)>& fn) -> void {
   StaticTask_t* task_buffer = static_cast<StaticTask_t*>(heap_caps_malloc(
       sizeof(StaticTask_t), MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT));
-  cpp::span<StackType_t> stack = AllocateStack<t>();
+  std::span<StackType_t> stack = AllocateStack<t>();
   xTaskCreateStatic(&PersistentMain, Name<t>().c_str(), stack.size(),
                     new std::function<void(void)>(fn), Priority<t>(),
                     stack.data(), task_buffer);
@@ -67,7 +67,7 @@ auto StartPersistent(BaseType_t core, const std::function<void(void)>& fn)
     -> void {
   StaticTask_t* task_buffer = static_cast<StaticTask_t*>(heap_caps_malloc(
       sizeof(StaticTask_t), MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT));
-  cpp::span<StackType_t> stack = AllocateStack<t>();
+  std::span<StackType_t> stack = AllocateStack<t>();
   xTaskCreateStaticPinnedToCore(&PersistentMain, Name<t>().c_str(),
                                 stack.size(), new std::function<void(void)>(fn),
                                 Priority<t>(), stack.data(), task_buffer, core);
diff --git a/src/ui/CMakeLists.txt b/src/ui/CMakeLists.txt
deleted file mode 100644
index 3814e9d5..00000000
--- a/src/ui/CMakeLists.txt
+++ /dev/null
@@ -1,11 +0,0 @@
-# Copyright 2023 jacqueline <me@jacqueline.id.au>
-#
-# SPDX-License-Identifier: GPL-3.0-only
-
-idf_component_register(
-  SRCS "lvgl_task.cpp" "ui_fsm.cpp" "screen_splash.cpp" "themes.cpp"
-  "screen.cpp" "modal.cpp"  "screen_lua.cpp" "splash.c" "font_fusion_12.c"
-  "font_fusion_10.c"
-  INCLUDE_DIRS "include"
-  REQUIRES "drivers" "lvgl" "tinyfsm" "events" "system_fsm" "database" "esp_timer" "battery" "lua" "luavgl" "esp_app_format" "input")
-target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})
diff --git a/src/ui/font_symbols.c b/src/ui/font_symbols.c
deleted file mode 100644
index abc380eb..00000000
--- a/src/ui/font_symbols.c
+++ /dev/null
@@ -1,425 +0,0 @@
-/*******************************************************************************
- * Size: 12 px
- * Bpp: 1
- * Opts: --font fonts/font-awesome/FontAwesome5-Solid+Brands+Regular.woff -r 0xf244,0xf243,0xf242,0xf241,0xf240 -r 0xf104,0xf0d7 -r 61441,61448,61451,61452,61452,61453,61457,61459,61461,61465 -r 61468,61473,61478,61479,61480,61502,61512,61515,61516,61517 -r 61521,61522,61523,61524,61543,61544,61550,61552,61553,61556 -r 61559,61560,61561,61563,61587,61589,61636,61637,61639,61671 -r 61674,61683,61724,61732,61787,61931,62016,62017,62018,62019 -r 62020,62087,62099,62212,62189,62810,63426,63650 --size 12 --bpp 1 --format lvgl -o font_symbols.c
- ******************************************************************************/
-
-#ifdef LV_LVGL_H_INCLUDE_SIMPLE
-#include "lvgl.h"
-#else
-#include "lvgl/lvgl.h"
-#endif
-
-#ifndef FONT_SYMBOLS
-#define FONT_SYMBOLS 1
-#endif
-
-#if FONT_SYMBOLS
-
-/*-----------------
- *    BITMAPS
- *----------------*/
-
-/*Store the image of the glyphs*/
-static LV_ATTRIBUTE_LARGE_CONST const uint8_t glyph_bitmap[] = {
-    /* U+F001 "" */
-    0x0, 0x70, 0x3f, 0x1f, 0xf1, 0xfb, 0x1c, 0x31,
-    0x83, 0x18, 0x31, 0x83, 0x19, 0xf7, 0x9f, 0xf8,
-    0x47, 0x0,
-
-    /* U+F008 "" */
-    0xbf, 0xde, 0x7, 0xa0, 0x5e, 0x7, 0xbf, 0xde,
-    0x7, 0xa0, 0x5e, 0x7, 0xbf, 0xd0,
-
-    /* U+F00B "" */
-    0xf7, 0xf7, 0xbf, 0xfd, 0xfe, 0x0, 0xf, 0x7f,
-    0x7b, 0xff, 0xdf, 0xc0, 0x0, 0xf7, 0xf7, 0xbf,
-    0xfd, 0xfc,
-
-    /* U+F00C "" */
-    0x0, 0x20, 0x7, 0x0, 0xe4, 0x1c, 0xe3, 0x87,
-    0x70, 0x3e, 0x1, 0xc0, 0x8, 0x0,
-
-    /* U+F00D "" */
-    0xc3, 0xe7, 0x7e, 0x3c, 0x3c, 0x7e, 0xe7, 0xc3,
-
-    /* U+F011 "" */
-    0x6, 0x2, 0x64, 0x76, 0xe6, 0x66, 0xc6, 0x3c,
-    0x63, 0xc6, 0x3c, 0x3, 0x60, 0x67, 0xe, 0x3f,
-    0xc0, 0xf0,
-
-    /* U+F013 "" */
-    0xe, 0x4, 0xf0, 0x7f, 0xef, 0xfe, 0x71, 0xe7,
-    0xc, 0x71, 0xef, 0xfe, 0x7f, 0xe4, 0xf0, 0xe,
-    0x0,
-
-    /* U+F015 "" */
-    0x3, 0x30, 0x1e, 0xc1, 0xcf, 0xc, 0xcc, 0x6f,
-    0xdb, 0x7f, 0xb3, 0xff, 0xf, 0x3c, 0x3c, 0xf0,
-    0xf3, 0xc0,
-
-    /* U+F019 "" */
-    0xe, 0x0, 0xe0, 0xe, 0x0, 0xe0, 0x3f, 0xc3,
-    0xf8, 0x1f, 0x0, 0xe0, 0xf5, 0xff, 0xff, 0xff,
-    0x5f, 0xff,
-
-    /* U+F01C "" */
-    0x1f, 0xe0, 0xc0, 0xc6, 0x1, 0x90, 0x2, 0xf8,
-    0x7f, 0xe1, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfc,
-
-    /* U+F021 "" */
-    0x0, 0x31, 0xf3, 0x71, 0xfc, 0x7, 0xc3, 0xf0,
-    0x0, 0x0, 0x0, 0x0, 0xfc, 0x3e, 0x3, 0xf8,
-    0xec, 0xf8, 0xc0, 0x0,
-
-    /* U+F026 "" */
-    0xc, 0x7f, 0xff, 0xff, 0xf1, 0xc3,
-
-    /* U+F027 "" */
-    0xc, 0xe, 0x3f, 0x7f, 0x9f, 0xdf, 0xe0, 0x70,
-    0x18,
-
-    /* U+F028 "" */
-    0x0, 0x60, 0x1, 0x83, 0x34, 0x38, 0xdf, 0xda,
-    0xfe, 0x57, 0xf6, 0xbf, 0x8d, 0x1c, 0xd0, 0x61,
-    0x80, 0x18,
-
-    /* U+F03E "" */
-    0xff, 0xf9, 0xff, 0x9f, 0xf9, 0xef, 0xfc, 0x7d,
-    0x83, 0xc0, 0x38, 0x3, 0xff, 0xf0,
-
-    /* U+F048 "" */
-    0xc3, 0xc7, 0xcf, 0xdf, 0xff, 0xff, 0xdf, 0xcf,
-    0xc7, 0xc3,
-
-    /* U+F04B "" */
-    0x0, 0x1c, 0x3, 0xe0, 0x7f, 0xf, 0xf9, 0xff,
-    0xbf, 0xff, 0xfe, 0xff, 0x9f, 0xc3, 0xe0, 0x70,
-    0x0, 0x0,
-
-    /* U+F04C "" */
-    0xfb, 0xff, 0x7f, 0xef, 0xfd, 0xff, 0xbf, 0xf7,
-    0xfe, 0xff, 0xdf, 0xfb, 0xff, 0x7c,
-
-    /* U+F04D "" */
-    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-    0xff, 0xff, 0xff, 0xff, 0xff, 0xfc,
-
-    /* U+F051 "" */
-    0xc3, 0xe3, 0xf3, 0xfb, 0xff, 0xff, 0xfb, 0xf3,
-    0xe3, 0xc3,
-
-    /* U+F052 "" */
-    0xc, 0x3, 0xc0, 0x7c, 0x1f, 0xc7, 0xfd, 0xff,
-    0xbf, 0xf0, 0x0, 0xff, 0xff, 0xff, 0xff, 0x80,
-
-    /* U+F053 "" */
-    0xc, 0x73, 0x9c, 0xe3, 0x87, 0xe, 0x1c, 0x30,
-
-    /* U+F054 "" */
-    0x83, 0x87, 0xe, 0x1c, 0x73, 0x9c, 0xe2, 0x0,
-
-    /* U+F067 "" */
-    0xe, 0x1, 0xc0, 0x38, 0x7, 0xf, 0xff, 0xff,
-    0xc3, 0x80, 0x70, 0xe, 0x1, 0xc0,
-
-    /* U+F068 "" */
-    0xff, 0xff, 0xfc,
-
-    /* U+F06E "" */
-    0xf, 0x81, 0xc7, 0x1c, 0x1d, 0xc6, 0x7e, 0xfb,
-    0xf7, 0xdd, 0xdd, 0xc7, 0x1c, 0xf, 0x80,
-
-    /* U+F070 "" */
-    0x0, 0x1, 0xc0, 0x1, 0xdf, 0x0, 0xe3, 0x80,
-    0xdb, 0x84, 0xfb, 0x9c, 0x77, 0x3c, 0x6e, 0x38,
-    0x78, 0x38, 0x70, 0x1e, 0x30, 0x0, 0x30, 0x0,
-    0x0,
-
-    /* U+F071 "" */
-    0x3, 0x0, 0x1c, 0x0, 0xf8, 0x3, 0xf0, 0x1c,
-    0xc0, 0x73, 0x83, 0xcf, 0x1f, 0xfc, 0x7c, 0xfb,
-    0xf3, 0xef, 0xff, 0x80,
-
-    /* U+F074 "" */
-    0x0, 0x0, 0x6, 0xe1, 0xff, 0x3f, 0x17, 0x60,
-    0xe4, 0x1f, 0x6f, 0xbf, 0xf1, 0xf0, 0x6, 0x0,
-    0x40,
-
-    /* U+F077 "" */
-    0x0, 0x3, 0x1, 0xe0, 0xcc, 0x61, 0xb0, 0x30,
-    0x0,
-
-    /* U+F078 "" */
-    0x0, 0x30, 0x36, 0x18, 0xcc, 0x1e, 0x3, 0x0,
-    0x0,
-
-    /* U+F079 "" */
-    0x30, 0x0, 0xf7, 0xf3, 0xf0, 0x65, 0xa0, 0xc3,
-    0x1, 0x86, 0xb, 0x4c, 0x1f, 0x9f, 0xde, 0x0,
-    0x18,
-
-    /* U+F07B "" */
-    0x78, 0xf, 0xc0, 0xff, 0xff, 0xff, 0xff, 0xff,
-    0xff, 0xff, 0xff, 0xff, 0xff, 0xf0,
-
-    /* U+F093 "" */
-    0x6, 0x0, 0xf0, 0x1f, 0x83, 0xfc, 0x7, 0x0,
-    0x70, 0x7, 0x0, 0x70, 0xf7, 0xff, 0xff, 0xff,
-    0x5f, 0xff,
-
-    /* U+F095 "" */
-    0x0, 0x0, 0xf, 0x0, 0xf0, 0x1f, 0x0, 0xf0,
-    0x6, 0x0, 0xe0, 0x1c, 0x73, 0xcf, 0xf8, 0xfe,
-    0xf, 0xc0, 0x40, 0x0,
-
-    /* U+F0C4 "" */
-    0x70, 0x5b, 0x3f, 0x6f, 0x3f, 0xc1, 0xf0, 0x3e,
-    0x1f, 0xe6, 0xde, 0xd9, 0xee, 0x8,
-
-    /* U+F0C5 "" */
-    0x1f, 0x43, 0xef, 0x7f, 0xef, 0xfd, 0xff, 0xbf,
-    0xf7, 0xfe, 0xff, 0xdf, 0xf8, 0x3, 0xfc, 0x0,
-
-    /* U+F0C7 "" */
-    0xff, 0x98, 0x1b, 0x3, 0xe0, 0x7c, 0xf, 0xff,
-    0xfe, 0x7f, 0x8f, 0xf9, 0xff, 0xfc,
-
-    /* U+F0D7 "" */
-    0xfe, 0xf8, 0xe0, 0x80,
-
-    /* U+F0E7 "" */
-    0x78, 0x78, 0xf8, 0xf0, 0xff, 0xfe, 0xfc, 0x1c,
-    0x18, 0x18, 0x10, 0x30,
-
-    /* U+F0EA "" */
-    0x18, 0x3b, 0x8e, 0xe3, 0xf8, 0xe0, 0x3b, 0xae,
-    0xe7, 0xbf, 0xef, 0xfb, 0xf0, 0xfc, 0x3f,
-
-    /* U+F0F3 "" */
-    0x4, 0x0, 0x80, 0x7c, 0x1f, 0xc3, 0xf8, 0x7f,
-    0x1f, 0xf3, 0xfe, 0x7f, 0xdf, 0xfc, 0x0, 0x7,
-    0x0,
-
-    /* U+F104 "" */
-    0x17, 0xec, 0xe7, 0x10,
-
-    /* U+F11C "" */
-    0xff, 0xff, 0x52, 0xbd, 0x4a, 0xff, 0xff, 0xeb,
-    0x5f, 0xff, 0xfd, 0x2, 0xf4, 0xb, 0xff, 0xfc,
-
-    /* U+F124 "" */
-    0x0, 0x0, 0xf, 0x3, 0xf0, 0xfe, 0x3f, 0xef,
-    0xfc, 0xff, 0xc0, 0x78, 0x7, 0x80, 0x78, 0x7,
-    0x0, 0x70, 0x2, 0x0,
-
-    /* U+F15B "" */
-    0xfa, 0x7d, 0xbe, 0xff, 0xf, 0xff, 0xff, 0xff,
-    0xff, 0xff, 0xff, 0xff, 0xff, 0xf0,
-
-    /* U+F1EB "" */
-    0x7, 0xc0, 0x7f, 0xf1, 0xe0, 0xf7, 0x0, 0x70,
-    0x7c, 0x3, 0xfe, 0x6, 0xc, 0x0, 0x0, 0x3,
-    0x80, 0x7, 0x0, 0xe, 0x0,
-
-    /* U+F240 "" */
-    0xff, 0xff, 0x80, 0x1f, 0x7f, 0xfe, 0xff, 0xbd,
-    0xff, 0xf8, 0x1, 0xff, 0xff, 0x80,
-
-    /* U+F241 "" */
-    0xff, 0xff, 0x80, 0x1f, 0x7f, 0x3e, 0xfe, 0x3d,
-    0xfc, 0xf8, 0x1, 0xff, 0xff, 0x80,
-
-    /* U+F242 "" */
-    0xff, 0xff, 0x80, 0x1f, 0x78, 0x3e, 0xf0, 0x3d,
-    0xe0, 0xf8, 0x1, 0xff, 0xff, 0x80,
-
-    /* U+F243 "" */
-    0xff, 0xff, 0x80, 0x1f, 0x60, 0x3e, 0xc0, 0x3d,
-    0x80, 0xf8, 0x1, 0xff, 0xff, 0x80,
-
-    /* U+F244 "" */
-    0xff, 0xff, 0x80, 0x1f, 0x0, 0x3e, 0x0, 0x3c,
-    0x0, 0xf8, 0x1, 0xff, 0xff, 0x80,
-
-    /* U+F287 "" */
-    0x0, 0xc0, 0x7, 0x80, 0x10, 0x7, 0x20, 0x6f,
-    0xff, 0xfc, 0x41, 0x80, 0x40, 0x0, 0xb8, 0x0,
-    0xf0,
-
-    /* U+F293 "" */
-    0x3e, 0x3b, 0x9c, 0xdb, 0x7c, 0xbf, 0x1f, 0x9f,
-    0x87, 0xd5, 0xf9, 0x9d, 0xc7, 0xc0,
-
-    /* U+F2ED "" */
-    0xe, 0x1f, 0xfc, 0x0, 0x0, 0x7, 0xfc, 0xd5,
-    0x9a, 0xb3, 0x56, 0x6a, 0xcd, 0x59, 0xab, 0x3f,
-    0xe0,
-
-    /* U+F304 "" */
-    0x0, 0x40, 0xe, 0x0, 0xf0, 0x37, 0x7, 0xa0,
-    0xfc, 0x1f, 0x83, 0xf0, 0x7e, 0xf, 0xc0, 0xf8,
-    0xf, 0x0, 0x80, 0x0,
-
-    /* U+F55A "" */
-    0xf, 0xfe, 0x3f, 0xfc, 0xfb, 0x3b, 0xf0, 0xff,
-    0xf3, 0xef, 0xc3, 0xcf, 0xb7, 0x8f, 0xff, 0xf,
-    0xfe,
-
-    /* U+F7C2 "" */
-    0x1f, 0x9a, 0xbe, 0xaf, 0xff, 0xff, 0xff, 0xff,
-    0xff, 0xff, 0xff, 0xff, 0xff, 0xf8,
-
-    /* U+F8A2 "" */
-    0x0, 0x0, 0x3, 0x30, 0x37, 0x3, 0xff, 0xff,
-    0xff, 0x70, 0x3, 0x0
-};
-
-
-/*---------------------
- *  GLYPH DESCRIPTION
- *--------------------*/
-
-static const lv_font_fmt_txt_glyph_dsc_t glyph_dsc[] = {
-    {.bitmap_index = 0, .adv_w = 0, .box_w = 0, .box_h = 0, .ofs_x = 0, .ofs_y = 0} /* id = 0 reserved */,
-    {.bitmap_index = 0, .adv_w = 192, .box_w = 12, .box_h = 12, .ofs_x = 0, .ofs_y = -2},
-    {.bitmap_index = 18, .adv_w = 192, .box_w = 12, .box_h = 9, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 32, .adv_w = 192, .box_w = 13, .box_h = 11, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 50, .adv_w = 192, .box_w = 12, .box_h = 9, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 64, .adv_w = 132, .box_w = 8, .box_h = 8, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 72, .adv_w = 192, .box_w = 12, .box_h = 12, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 90, .adv_w = 192, .box_w = 12, .box_h = 11, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 107, .adv_w = 216, .box_w = 14, .box_h = 10, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 125, .adv_w = 192, .box_w = 12, .box_h = 12, .ofs_x = 0, .ofs_y = -2},
-    {.bitmap_index = 143, .adv_w = 216, .box_w = 14, .box_h = 9, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 159, .adv_w = 192, .box_w = 12, .box_h = 13, .ofs_x = 0, .ofs_y = -2},
-    {.bitmap_index = 179, .adv_w = 96, .box_w = 6, .box_h = 8, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 185, .adv_w = 144, .box_w = 9, .box_h = 8, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 194, .adv_w = 216, .box_w = 13, .box_h = 11, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 212, .adv_w = 192, .box_w = 12, .box_h = 9, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 226, .adv_w = 168, .box_w = 8, .box_h = 10, .ofs_x = 1, .ofs_y = -1},
-    {.bitmap_index = 236, .adv_w = 168, .box_w = 11, .box_h = 13, .ofs_x = 0, .ofs_y = -2},
-    {.bitmap_index = 254, .adv_w = 168, .box_w = 11, .box_h = 10, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 268, .adv_w = 168, .box_w = 11, .box_h = 10, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 282, .adv_w = 168, .box_w = 8, .box_h = 10, .ofs_x = 1, .ofs_y = -1},
-    {.bitmap_index = 292, .adv_w = 168, .box_w = 11, .box_h = 11, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 308, .adv_w = 120, .box_w = 6, .box_h = 10, .ofs_x = 1, .ofs_y = -1},
-    {.bitmap_index = 316, .adv_w = 120, .box_w = 6, .box_h = 10, .ofs_x = 1, .ofs_y = -1},
-    {.bitmap_index = 324, .adv_w = 168, .box_w = 11, .box_h = 10, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 338, .adv_w = 168, .box_w = 11, .box_h = 2, .ofs_x = 0, .ofs_y = 3},
-    {.bitmap_index = 341, .adv_w = 216, .box_w = 13, .box_h = 9, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 356, .adv_w = 240, .box_w = 15, .box_h = 13, .ofs_x = 0, .ofs_y = -2},
-    {.bitmap_index = 381, .adv_w = 216, .box_w = 14, .box_h = 11, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 401, .adv_w = 192, .box_w = 12, .box_h = 11, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 418, .adv_w = 168, .box_w = 10, .box_h = 7, .ofs_x = 0, .ofs_y = 1},
-    {.bitmap_index = 427, .adv_w = 168, .box_w = 10, .box_h = 7, .ofs_x = 0, .ofs_y = 1},
-    {.bitmap_index = 436, .adv_w = 240, .box_w = 15, .box_h = 9, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 453, .adv_w = 192, .box_w = 12, .box_h = 9, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 467, .adv_w = 192, .box_w = 12, .box_h = 12, .ofs_x = 0, .ofs_y = -2},
-    {.bitmap_index = 485, .adv_w = 192, .box_w = 12, .box_h = 13, .ofs_x = 0, .ofs_y = -2},
-    {.bitmap_index = 505, .adv_w = 168, .box_w = 11, .box_h = 10, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 519, .adv_w = 168, .box_w = 11, .box_h = 11, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 535, .adv_w = 168, .box_w = 11, .box_h = 10, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 549, .adv_w = 120, .box_w = 7, .box_h = 4, .ofs_x = 0, .ofs_y = 2},
-    {.bitmap_index = 553, .adv_w = 120, .box_w = 8, .box_h = 12, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 565, .adv_w = 168, .box_w = 10, .box_h = 12, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 580, .adv_w = 168, .box_w = 11, .box_h = 12, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 597, .adv_w = 96, .box_w = 4, .box_h = 7, .ofs_x = 1, .ofs_y = 1},
-    {.bitmap_index = 601, .adv_w = 216, .box_w = 14, .box_h = 9, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 617, .adv_w = 192, .box_w = 12, .box_h = 13, .ofs_x = 0, .ofs_y = -2},
-    {.bitmap_index = 637, .adv_w = 144, .box_w = 9, .box_h = 12, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 651, .adv_w = 240, .box_w = 15, .box_h = 11, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 672, .adv_w = 240, .box_w = 15, .box_h = 7, .ofs_x = 0, .ofs_y = 1},
-    {.bitmap_index = 686, .adv_w = 240, .box_w = 15, .box_h = 7, .ofs_x = 0, .ofs_y = 1},
-    {.bitmap_index = 700, .adv_w = 240, .box_w = 15, .box_h = 7, .ofs_x = 0, .ofs_y = 1},
-    {.bitmap_index = 714, .adv_w = 240, .box_w = 15, .box_h = 7, .ofs_x = 0, .ofs_y = 1},
-    {.bitmap_index = 728, .adv_w = 240, .box_w = 15, .box_h = 7, .ofs_x = 0, .ofs_y = 1},
-    {.bitmap_index = 742, .adv_w = 240, .box_w = 15, .box_h = 9, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 759, .adv_w = 168, .box_w = 9, .box_h = 12, .ofs_x = 1, .ofs_y = -2},
-    {.bitmap_index = 773, .adv_w = 168, .box_w = 11, .box_h = 12, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 790, .adv_w = 192, .box_w = 12, .box_h = 13, .ofs_x = 0, .ofs_y = -2},
-    {.bitmap_index = 810, .adv_w = 240, .box_w = 15, .box_h = 9, .ofs_x = 0, .ofs_y = 0},
-    {.bitmap_index = 827, .adv_w = 144, .box_w = 10, .box_h = 11, .ofs_x = 0, .ofs_y = -1},
-    {.bitmap_index = 841, .adv_w = 193, .box_w = 12, .box_h = 8, .ofs_x = 0, .ofs_y = 1}
-};
-
-/*---------------------
- *  CHARACTER MAPPING
- *--------------------*/
-
-static const uint16_t unicode_list_0[] = {
-    0x0, 0x7, 0xa, 0xb, 0xc, 0x10, 0x12, 0x14,
-    0x18, 0x1b, 0x20, 0x25, 0x26, 0x27, 0x3d, 0x47,
-    0x4a, 0x4b, 0x4c, 0x50, 0x51, 0x52, 0x53, 0x66,
-    0x67, 0x6d, 0x6f, 0x70, 0x73, 0x76, 0x77, 0x78,
-    0x7a, 0x92, 0x94, 0xc3, 0xc4, 0xc6, 0xd6, 0xe6,
-    0xe9, 0xf2, 0x103, 0x11b, 0x123, 0x15a, 0x1ea, 0x23f,
-    0x240, 0x241, 0x242, 0x243, 0x286, 0x292, 0x2ec, 0x303,
-    0x559, 0x7c1, 0x8a1
-};
-
-/*Collect the unicode lists and glyph_id offsets*/
-static const lv_font_fmt_txt_cmap_t cmaps[] =
-{
-    {
-        .range_start = 61441, .range_length = 2210, .glyph_id_start = 1,
-        .unicode_list = unicode_list_0, .glyph_id_ofs_list = NULL, .list_length = 59, .type = LV_FONT_FMT_TXT_CMAP_SPARSE_TINY
-    }
-};
-
-
-
-/*--------------------
- *  ALL CUSTOM DATA
- *--------------------*/
-
-#if LV_VERSION_CHECK(8, 0, 0)
-/*Store all the custom data of the font*/
-static  lv_font_fmt_txt_glyph_cache_t cache;
-static const lv_font_fmt_txt_dsc_t font_dsc = {
-#else
-static lv_font_fmt_txt_dsc_t font_dsc = {
-#endif
-    .glyph_bitmap = glyph_bitmap,
-    .glyph_dsc = glyph_dsc,
-    .cmaps = cmaps,
-    .kern_dsc = NULL,
-    .kern_scale = 0,
-    .cmap_num = 1,
-    .bpp = 1,
-    .kern_classes = 0,
-    .bitmap_format = 0,
-#if LV_VERSION_CHECK(8, 0, 0)
-    .cache = &cache
-#endif
-};
-
-
-/*-----------------
- *  PUBLIC FONT
- *----------------*/
-
-/*Initialize a public general font descriptor*/
-#if LV_VERSION_CHECK(8, 0, 0)
-const lv_font_t font_symbols = {
-#else
-lv_font_t font_symbols = {
-#endif
-    .get_glyph_dsc = lv_font_get_glyph_dsc_fmt_txt,    /*Function pointer to get glyph's data*/
-    .get_glyph_bitmap = lv_font_get_bitmap_fmt_txt,    /*Function pointer to get glyph's bitmap*/
-    .line_height = 13,          /*The maximum line height required by the font*/
-    .base_line = 2,             /*Baseline measured from the bottom of the line*/
-#if !(LVGL_VERSION_MAJOR == 6 && LVGL_VERSION_MINOR == 0)
-    .subpx = LV_FONT_SUBPX_NONE,
-#endif
-#if LV_VERSION_CHECK(7, 4, 0) || LVGL_VERSION_MAJOR >= 8
-    .underline_position = -4,
-    .underline_thickness = 1,
-#endif
-    .dsc = &font_dsc           /*The custom font data. Will be accessed by `get_glyph_bitmap/dsc` */
-};
-
-
-
-#endif /*#if FONT_SYMBOLS*/
-
diff --git a/src/ui/icons/battery_20.c b/src/ui/icons/battery_20.c
deleted file mode 100644
index 3be6b614..00000000
--- a/src/ui/icons/battery_20.c
+++ /dev/null
@@ -1,52 +0,0 @@
-#ifdef __has_include
-    #if __has_include("lvgl.h")
-        #ifndef LV_LVGL_H_INCLUDE_SIMPLE
-            #define LV_LVGL_H_INCLUDE_SIMPLE
-        #endif
-    #endif
-#endif
-
-#if defined(LV_LVGL_H_INCLUDE_SIMPLE)
-    #include "lvgl.h"
-#else
-    #include "lvgl/lvgl.h"
-#endif
-
-
-#ifndef LV_ATTRIBUTE_MEM_ALIGN
-#define LV_ATTRIBUTE_MEM_ALIGN
-#endif
-
-#ifndef LV_ATTRIBUTE_IMG_BATTERY_20
-#define LV_ATTRIBUTE_IMG_BATTERY_20
-#endif
-
-static const LV_ATTRIBUTE_MEM_ALIGN LV_ATTRIBUTE_LARGE_CONST LV_ATTRIBUTE_IMG_BATTERY_20 uint8_t battery_20_map[] = {
-  0x00, 0x00, 0x00, 0xff, 	/*Color of index 0*/
-  0xfd, 0xfe, 0xfd, 0xff, 	/*Color of index 1*/
-  0x26, 0xc1, 0x38, 0xff, 	/*Color of index 2*/
-  0x01, 0xbe, 0x37, 0xff, 	/*Color of index 3*/
-
-  0x55, 0x00, 0x55, 
-  0x54, 0x00, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xff, 0x15, 
-  0x54, 0x00, 0x15, 
-};
-
-const lv_img_dsc_t kIconBattery20 = {
-  .header.cf = LV_IMG_CF_INDEXED_2BIT,
-  .header.always_zero = 0,
-  .header.reserved = 0,
-  .header.w = 12,
-  .header.h = 12,
-  .data_size = 52,
-  .data = battery_20_map,
-};
diff --git a/src/ui/icons/battery_40.c b/src/ui/icons/battery_40.c
deleted file mode 100644
index 4a6ead0c..00000000
--- a/src/ui/icons/battery_40.c
+++ /dev/null
@@ -1,52 +0,0 @@
-#ifdef __has_include
-    #if __has_include("lvgl.h")
-        #ifndef LV_LVGL_H_INCLUDE_SIMPLE
-            #define LV_LVGL_H_INCLUDE_SIMPLE
-        #endif
-    #endif
-#endif
-
-#if defined(LV_LVGL_H_INCLUDE_SIMPLE)
-    #include "lvgl.h"
-#else
-    #include "lvgl/lvgl.h"
-#endif
-
-
-#ifndef LV_ATTRIBUTE_MEM_ALIGN
-#define LV_ATTRIBUTE_MEM_ALIGN
-#endif
-
-#ifndef LV_ATTRIBUTE_IMG_BATTERY_40
-#define LV_ATTRIBUTE_IMG_BATTERY_40
-#endif
-
-static const LV_ATTRIBUTE_MEM_ALIGN LV_ATTRIBUTE_LARGE_CONST LV_ATTRIBUTE_IMG_BATTERY_40 uint8_t battery_40_map[] = {
-  0x00, 0x00, 0x00, 0xff, 	/*Color of index 0*/
-  0xfd, 0xfe, 0xfd, 0xff, 	/*Color of index 1*/
-  0x26, 0xc1, 0x38, 0xff, 	/*Color of index 2*/
-  0x01, 0xbe, 0x37, 0xff, 	/*Color of index 3*/
-
-  0x55, 0x00, 0x55, 
-  0x54, 0x00, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xff, 0x15, 
-  0x54, 0xff, 0x15, 
-  0x54, 0x00, 0x15, 
-};
-
-const lv_img_dsc_t kIconBattery40 = {
-  .header.cf = LV_IMG_CF_INDEXED_2BIT,
-  .header.always_zero = 0,
-  .header.reserved = 0,
-  .header.w = 12,
-  .header.h = 12,
-  .data_size = 52,
-  .data = battery_40_map,
-};
diff --git a/src/ui/icons/battery_60.c b/src/ui/icons/battery_60.c
deleted file mode 100644
index 4695cb73..00000000
--- a/src/ui/icons/battery_60.c
+++ /dev/null
@@ -1,52 +0,0 @@
-#ifdef __has_include
-    #if __has_include("lvgl.h")
-        #ifndef LV_LVGL_H_INCLUDE_SIMPLE
-            #define LV_LVGL_H_INCLUDE_SIMPLE
-        #endif
-    #endif
-#endif
-
-#if defined(LV_LVGL_H_INCLUDE_SIMPLE)
-    #include "lvgl.h"
-#else
-    #include "lvgl/lvgl.h"
-#endif
-
-
-#ifndef LV_ATTRIBUTE_MEM_ALIGN
-#define LV_ATTRIBUTE_MEM_ALIGN
-#endif
-
-#ifndef LV_ATTRIBUTE_IMG_BATTERY_60
-#define LV_ATTRIBUTE_IMG_BATTERY_60
-#endif
-
-static const LV_ATTRIBUTE_MEM_ALIGN LV_ATTRIBUTE_LARGE_CONST LV_ATTRIBUTE_IMG_BATTERY_60 uint8_t battery_60_map[] = {
-  0x00, 0x00, 0x00, 0xff, 	/*Color of index 0*/
-  0xfd, 0xfe, 0xfd, 0xff, 	/*Color of index 1*/
-  0x26, 0xc1, 0x38, 0xff, 	/*Color of index 2*/
-  0x01, 0xbe, 0x37, 0xff, 	/*Color of index 3*/
-
-  0x55, 0x00, 0x55, 
-  0x54, 0x00, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xff, 0x15, 
-  0x54, 0xff, 0x15, 
-  0x54, 0x00, 0x15, 
-};
-
-const lv_img_dsc_t kIconBattery60 = {
-  .header.cf = LV_IMG_CF_INDEXED_2BIT,
-  .header.always_zero = 0,
-  .header.reserved = 0,
-  .header.w = 12,
-  .header.h = 12,
-  .data_size = 52,
-  .data = battery_60_map,
-};
diff --git a/src/ui/icons/battery_80.c b/src/ui/icons/battery_80.c
deleted file mode 100644
index e0b60dfe..00000000
--- a/src/ui/icons/battery_80.c
+++ /dev/null
@@ -1,52 +0,0 @@
-#ifdef __has_include
-    #if __has_include("lvgl.h")
-        #ifndef LV_LVGL_H_INCLUDE_SIMPLE
-            #define LV_LVGL_H_INCLUDE_SIMPLE
-        #endif
-    #endif
-#endif
-
-#if defined(LV_LVGL_H_INCLUDE_SIMPLE)
-    #include "lvgl.h"
-#else
-    #include "lvgl/lvgl.h"
-#endif
-
-
-#ifndef LV_ATTRIBUTE_MEM_ALIGN
-#define LV_ATTRIBUTE_MEM_ALIGN
-#endif
-
-#ifndef LV_ATTRIBUTE_IMG_BATTERY_80
-#define LV_ATTRIBUTE_IMG_BATTERY_80
-#endif
-
-static const LV_ATTRIBUTE_MEM_ALIGN LV_ATTRIBUTE_LARGE_CONST LV_ATTRIBUTE_IMG_BATTERY_80 uint8_t battery_80_map[] = {
-  0x00, 0x00, 0x00, 0xff, 	/*Color of index 0*/
-  0xfd, 0xfe, 0xfd, 0xff, 	/*Color of index 1*/
-  0x26, 0xc1, 0x38, 0xff, 	/*Color of index 2*/
-  0x01, 0xbe, 0x37, 0xff, 	/*Color of index 3*/
-
-  0x55, 0x00, 0x55, 
-  0x54, 0x00, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0x55, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xff, 0x15, 
-  0x54, 0xff, 0x15, 
-  0x54, 0x00, 0x15, 
-};
-
-const lv_img_dsc_t kIconBattery80 = {
-  .header.cf = LV_IMG_CF_INDEXED_2BIT,
-  .header.always_zero = 0,
-  .header.reserved = 0,
-  .header.w = 12,
-  .header.h = 12,
-  .data_size = 52,
-  .data = battery_80_map,
-};
diff --git a/src/ui/icons/battery_empty.c b/src/ui/icons/battery_empty.c
deleted file mode 100644
index 26f84863..00000000
--- a/src/ui/icons/battery_empty.c
+++ /dev/null
@@ -1,52 +0,0 @@
-#ifdef __has_include
-    #if __has_include("lvgl.h")
-        #ifndef LV_LVGL_H_INCLUDE_SIMPLE
-            #define LV_LVGL_H_INCLUDE_SIMPLE
-        #endif
-    #endif
-#endif
-
-#if defined(LV_LVGL_H_INCLUDE_SIMPLE)
-    #include "lvgl.h"
-#else
-    #include "lvgl/lvgl.h"
-#endif
-
-
-#ifndef LV_ATTRIBUTE_MEM_ALIGN
-#define LV_ATTRIBUTE_MEM_ALIGN
-#endif
-
-#ifndef LV_ATTRIBUTE_IMG_BATTERY_EMPTY
-#define LV_ATTRIBUTE_IMG_BATTERY_EMPTY
-#endif
-
-const LV_ATTRIBUTE_MEM_ALIGN LV_ATTRIBUTE_LARGE_CONST LV_ATTRIBUTE_IMG_BATTERY_EMPTY uint8_t battery_empty_map[] = {
-  0xfd, 0xfd, 0xfd, 0xff, 	/*Color of index 0*/
-  0x00, 0x00, 0x00, 0xff, 	/*Color of index 1*/
-  0x26, 0x2c, 0xfa, 0xff, 	/*Color of index 2*/
-  0x00, 0x00, 0x00, 0x00, 	/*Color of index 3*/
-
-  0x00, 0x55, 0x00, 
-  0x01, 0x55, 0x40, 
-  0x01, 0x00, 0x40, 
-  0x01, 0x00, 0x40, 
-  0x01, 0x00, 0x40, 
-  0x01, 0x00, 0x40, 
-  0x01, 0x00, 0x40, 
-  0x01, 0x00, 0x40, 
-  0x01, 0x00, 0x40, 
-  0x01, 0xaa, 0x40, 
-  0x01, 0xaa, 0x40, 
-  0x01, 0x55, 0x40, 
-};
-
-const lv_img_dsc_t kIconBatteryEmpty = {
-  .header.cf = LV_IMG_CF_INDEXED_2BIT,
-  .header.always_zero = 0,
-  .header.reserved = 0,
-  .header.w = 12,
-  .header.h = 12,
-  .data_size = 52,
-  .data = battery_empty_map,
-};
diff --git a/src/ui/icons/battery_full.c b/src/ui/icons/battery_full.c
deleted file mode 100644
index 1e3b17e3..00000000
--- a/src/ui/icons/battery_full.c
+++ /dev/null
@@ -1,52 +0,0 @@
-#ifdef __has_include
-    #if __has_include("lvgl.h")
-        #ifndef LV_LVGL_H_INCLUDE_SIMPLE
-            #define LV_LVGL_H_INCLUDE_SIMPLE
-        #endif
-    #endif
-#endif
-
-#if defined(LV_LVGL_H_INCLUDE_SIMPLE)
-    #include "lvgl.h"
-#else
-    #include "lvgl/lvgl.h"
-#endif
-
-
-#ifndef LV_ATTRIBUTE_MEM_ALIGN
-#define LV_ATTRIBUTE_MEM_ALIGN
-#endif
-
-#ifndef LV_ATTRIBUTE_IMG_BATTERY_FULL
-#define LV_ATTRIBUTE_IMG_BATTERY_FULL
-#endif
-
-const LV_ATTRIBUTE_MEM_ALIGN LV_ATTRIBUTE_LARGE_CONST LV_ATTRIBUTE_IMG_BATTERY_FULL uint8_t battery_full_map[] = {
-  0x00, 0x00, 0x00, 0xff, 	/*Color of index 0*/
-  0xfd, 0xfe, 0xfd, 0xff, 	/*Color of index 1*/
-  0x26, 0xc1, 0x38, 0xff, 	/*Color of index 2*/
-  0x01, 0xbe, 0x37, 0xff, 	/*Color of index 3*/
-
-  0x55, 0x00, 0x55, 
-  0x54, 0x00, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xaa, 0x15, 
-  0x54, 0xff, 0x15, 
-  0x54, 0xff, 0x15, 
-  0x54, 0x00, 0x15, 
-};
-
-const lv_img_dsc_t kIconBatteryFull = {
-  .header.cf = LV_IMG_CF_INDEXED_2BIT,
-  .header.always_zero = 0,
-  .header.reserved = 0,
-  .header.w = 12,
-  .header.h = 12,
-  .data_size = 52,
-  .data = battery_full_map,
-};
diff --git a/src/ui/icons/bluetooth.c b/src/ui/icons/bluetooth.c
deleted file mode 100644
index 66322f8f..00000000
--- a/src/ui/icons/bluetooth.c
+++ /dev/null
@@ -1,54 +0,0 @@
-#ifdef __has_include
-    #if __has_include("lvgl.h")
-        #ifndef LV_LVGL_H_INCLUDE_SIMPLE
-            #define LV_LVGL_H_INCLUDE_SIMPLE
-        #endif
-    #endif
-#endif
-
-#if defined(LV_LVGL_H_INCLUDE_SIMPLE)
-    #include "lvgl.h"
-#else
-    #include "lvgl/lvgl.h"
-#endif
-
-
-#ifndef LV_ATTRIBUTE_MEM_ALIGN
-#define LV_ATTRIBUTE_MEM_ALIGN
-#endif
-
-#ifndef LV_ATTRIBUTE_IMG_BLUETOOTH
-#define LV_ATTRIBUTE_IMG_BLUETOOTH
-#endif
-
-static const LV_ATTRIBUTE_MEM_ALIGN LV_ATTRIBUTE_LARGE_CONST LV_ATTRIBUTE_IMG_BLUETOOTH uint8_t bluetooth_map[] = {
-  0xfe, 0xfe, 0xfe, 0xff, 	/*Color of index 0*/
-  0xff, 0x75, 0x00, 0xff, 	/*Color of index 1*/
-  0x00, 0x00, 0x00, 0x00, 	/*Color of index 2*/
-  0x00, 0x00, 0x00, 0x00, 	/*Color of index 3*/
-
-  0x00, 0x55, 0x40, 0x00, 
-  0x01, 0x51, 0x50, 0x00, 
-  0x05, 0x50, 0x54, 0x00, 
-  0x05, 0x51, 0x14, 0x00, 
-  0x05, 0x11, 0x04, 0x00, 
-  0x15, 0x40, 0x15, 0x00, 
-  0x15, 0x50, 0x55, 0x00, 
-  0x15, 0x40, 0x15, 0x00, 
-  0x05, 0x11, 0x04, 0x00, 
-  0x05, 0x51, 0x14, 0x00, 
-  0x05, 0x50, 0x54, 0x00, 
-  0x01, 0x51, 0x50, 0x00, 
-  0x00, 0x55, 0x40, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-};
-
-const lv_img_dsc_t kIconBluetooth = {
-  .header.cf = LV_IMG_CF_INDEXED_2BIT,
-  .header.always_zero = 0,
-  .header.reserved = 0,
-  .header.w = 14,
-  .header.h = 14,
-  .data_size = 72,
-  .data = bluetooth_map,
-};
diff --git a/src/ui/icons/pause.c b/src/ui/icons/pause.c
deleted file mode 100644
index 8201b5bb..00000000
--- a/src/ui/icons/pause.c
+++ /dev/null
@@ -1,54 +0,0 @@
-#ifdef __has_include
-    #if __has_include("lvgl.h")
-        #ifndef LV_LVGL_H_INCLUDE_SIMPLE
-            #define LV_LVGL_H_INCLUDE_SIMPLE
-        #endif
-    #endif
-#endif
-
-#if defined(LV_LVGL_H_INCLUDE_SIMPLE)
-    #include "lvgl.h"
-#else
-    #include "lvgl/lvgl.h"
-#endif
-
-
-#ifndef LV_ATTRIBUTE_MEM_ALIGN
-#define LV_ATTRIBUTE_MEM_ALIGN
-#endif
-
-#ifndef LV_ATTRIBUTE_IMG_PAUSE
-#define LV_ATTRIBUTE_IMG_PAUSE
-#endif
-
-static const LV_ATTRIBUTE_MEM_ALIGN LV_ATTRIBUTE_LARGE_CONST LV_ATTRIBUTE_IMG_PAUSE uint8_t pause_map[] = {
-  0xfe, 0xfe, 0xfe, 0xff, 	/*Color of index 0*/
-  0x00, 0x00, 0x00, 0xff, 	/*Color of index 1*/
-  0x00, 0x00, 0x00, 0x00, 	/*Color of index 2*/
-  0x00, 0x00, 0x00, 0x00, 	/*Color of index 3*/
-
-  0x00, 0x00, 0x00, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-  0x00, 0x50, 0x14, 0x00, 
-  0x00, 0x50, 0x14, 0x00, 
-  0x00, 0x50, 0x14, 0x00, 
-  0x00, 0x50, 0x14, 0x00, 
-  0x00, 0x50, 0x14, 0x00, 
-  0x00, 0x50, 0x14, 0x00, 
-  0x00, 0x50, 0x14, 0x00, 
-  0x00, 0x50, 0x14, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-};
-
-const lv_img_dsc_t kIconPause = {
-  .header.cf = LV_IMG_CF_INDEXED_2BIT,
-  .header.always_zero = 0,
-  .header.reserved = 0,
-  .header.w = 14,
-  .header.h = 14,
-  .data_size = 72,
-  .data = pause_map,
-};
diff --git a/src/ui/icons/play.c b/src/ui/icons/play.c
deleted file mode 100644
index 8984eae4..00000000
--- a/src/ui/icons/play.c
+++ /dev/null
@@ -1,54 +0,0 @@
-#ifdef __has_include
-    #if __has_include("lvgl.h")
-        #ifndef LV_LVGL_H_INCLUDE_SIMPLE
-            #define LV_LVGL_H_INCLUDE_SIMPLE
-        #endif
-    #endif
-#endif
-
-#if defined(LV_LVGL_H_INCLUDE_SIMPLE)
-    #include "lvgl.h"
-#else
-    #include "lvgl/lvgl.h"
-#endif
-
-
-#ifndef LV_ATTRIBUTE_MEM_ALIGN
-#define LV_ATTRIBUTE_MEM_ALIGN
-#endif
-
-#ifndef LV_ATTRIBUTE_IMG_PLAY
-#define LV_ATTRIBUTE_IMG_PLAY
-#endif
-
-static const LV_ATTRIBUTE_MEM_ALIGN LV_ATTRIBUTE_LARGE_CONST LV_ATTRIBUTE_IMG_PLAY uint8_t play_map[] = {
-  0xfe, 0xfe, 0xfe, 0xff, 	/*Color of index 0*/
-  0x00, 0x00, 0x00, 0xff, 	/*Color of index 1*/
-  0x00, 0x00, 0x00, 0x00, 	/*Color of index 2*/
-  0x00, 0x00, 0x00, 0x00, 	/*Color of index 3*/
-
-  0x00, 0x00, 0x00, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-  0x00, 0x50, 0x00, 0x00, 
-  0x00, 0x55, 0x00, 0x00, 
-  0x00, 0x55, 0x50, 0x00, 
-  0x00, 0x55, 0x54, 0x00, 
-  0x00, 0x55, 0x54, 0x00, 
-  0x00, 0x55, 0x50, 0x00, 
-  0x00, 0x55, 0x00, 0x00, 
-  0x00, 0x50, 0x00, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-  0x00, 0x00, 0x00, 0x00, 
-};
-
-const lv_img_dsc_t kIconPlay = {
-  .header.cf = LV_IMG_CF_INDEXED_2BIT,
-  .header.always_zero = 0,
-  .header.reserved = 0,
-  .header.w = 14,
-  .header.h = 14,
-  .data_size = 72,
-  .data = play_map,
-};
diff --git a/src/ui/include/ui_tick.hpp b/src/ui/include/ui_tick.hpp
deleted file mode 100644
index 37f8a8bd..00000000
--- a/src/ui/include/ui_tick.hpp
+++ /dev/null
@@ -1,11 +0,0 @@
-/*
- * Copyright 2023 jacqueline <me@jacqueline.id.au>
- *
- * SPDX-License-Identifier: GPL-3.0-only
- */
-
-#pragma once
-
-#include "esp_timer.h"
-
-#define LV_TICK_CUSTOM_SYS_TIME_EXPR (esp_timer_get_time() / 1000)
diff --git a/src/util/CMakeLists.txt b/src/util/CMakeLists.txt
index bb4ce320..49554be8 100644
--- a/src/util/CMakeLists.txt
+++ b/src/util/CMakeLists.txt
@@ -2,4 +2,4 @@
 #
 # SPDX-License-Identifier: GPL-3.0-only
 
-idf_component_register(SRCS INCLUDE_DIRS "include" REQUIRES "database" "span")
+idf_component_register(SRCS INCLUDE_DIRS "include" REQUIRES "memory")
diff --git a/src/util/include/debug.hpp b/src/util/include/debug.hpp
index 620b0974..27fb2999 100644
--- a/src/util/include/debug.hpp
+++ b/src/util/include/debug.hpp
@@ -8,13 +8,12 @@
 
 #include <iomanip>
 #include <ostream>
-
+#include <span>
 #include <string>
-#include "span.hpp"
 
 namespace util {
 
-inline std::string format_hex_string(cpp::span<const std::byte> data) {
+inline std::string format_hex_string(std::span<const std::byte> data) {
   std::ostringstream oss;
   std::ostringstream ascii_values;
   int count = 0;
diff --git a/src/util/random.cpp b/src/util/random.cpp
index ae543765..2b2af9c7 100644
--- a/src/util/random.cpp
+++ b/src/util/random.cpp
@@ -29,8 +29,8 @@ auto Random::Next() -> std::uint64_t {
   return komirand(&seed1_, &seed2_);
 }
 
-auto Random::RangeInclusive(std::uint64_t lower, std::uint64_t upper)
-    -> std::uint64_t {
+auto Random::RangeInclusive(std::uint64_t lower,
+                            std::uint64_t upper) -> std::uint64_t {
   return (Next() % (upper - lower + 1)) + lower;
 }