1 files changed, 97 insertions, 0 deletions
diff --git a/src/audio/include/audio_playback.hpp b/src/audio/include/audio_playback.hpp
new file mode 100644
index 00000000..41ab46d2
--- /dev/null
+++ b/src/audio/include/audio_playback.hpp
@@ -0,0 +1,97 @@
+#pragma once
+
+#include <cstdint>
+#include <memory>
+#include <string>
+
+#include "audio_common.h"
+#include "audio_element.h"
+#include "audio_event_iface.h"
+#include "audio_pipeline.h"
+#include "esp_err.h"
+#include "fatfs_stream.h"
+#include "i2s_stream.h"
+#include "mp3_decoder.h"
+#include "result.hpp"
+
+#include "audio_output.hpp"
+#include "dac.hpp"
+#include "storage.hpp"
+
+namespace drivers {
+
+/*
+ * Sends an I2S audio stream to the DAC. Includes basic controls for pausing
+ * and resuming the stream, as well as support for gapless playback of the next
+ * queued song, but does not implement any kind of sophisticated queing or
+ * playback control; these should be handled at a higher level.
+ */
+class AudioPlayback {
+ public:
+  enum Error { FATFS_INIT, I2S_INIT, PIPELINE_INIT };
+  static auto create(std::unique_ptr<IAudioOutput> output)
+      -> cpp::result<std::unique_ptr<AudioPlayback>, Error>;
+
+  AudioPlayback(std::unique_ptr<IAudioOutput>& output,
+                audio_pipeline_handle_t pipeline,
+                audio_element_handle_t source_element,
+                audio_event_iface_handle_t event_interface);
+  ~AudioPlayback();
+
+  /*
+   * Replaces any currently playing file with the one given, and begins
+   * playback.
+   *
+   * Any value set in `set_next_file` is cleared by this method.
+   */
+  auto Play(const std::string& filename) -> void;
+  /* Toogle between resumed and paused. */
+  auto Toggle() -> void;
+  auto Resume() -> void;
+  auto Pause() -> void;
+
+  enum PlaybackState { PLAYING, PAUSED, STOPPED };
+  auto GetPlaybackState() const -> PlaybackState;
+
+  /*
+   * Handles any pending events from the underlying audio pipeline. This must
+   * be called regularly in order to handle configuring the I2S stream for
+   * different audio types (e.g. sample rate, bit depth), and for gapless
+   * playback.
+   */
+  auto ProcessEvents(uint16_t max_time_ms) -> void;
+
+  /*
+   * Sets the file that should be played immediately after the current file
+   * finishes. This is used for gapless playback
+   */
+  auto SetNextFile(const std::string& filename) -> void;
+
+  auto SetVolume(uint8_t volume) -> void;
+  auto GetVolume() const -> uint8_t;
+
+  // Not copyable or movable.
+  AudioPlayback(const AudioPlayback&) = delete;
+  AudioPlayback& operator=(const AudioPlayback&) = delete;
+
+ private:
+  PlaybackState playback_state_;
+
+  enum Decoder { NONE, MP3, AMR, OPUS, OGG, FLAC, WAV, AAC };
+  auto GetDecoderForFilename(std::string filename) const -> Decoder;
+  auto CreateDecoder(Decoder decoder) const -> audio_element_handle_t;
+  auto ReconfigurePipeline(Decoder decoder) -> void;
+
+  std::unique_ptr<IAudioOutput> output_;
+
+  std::string next_filename_ = "";
+
+  audio_pipeline_handle_t pipeline_;
+  audio_element_handle_t source_element_;
+  audio_event_iface_handle_t event_interface_;
+
+  audio_element_handle_t decoder_ = nullptr;
+  Decoder decoder_type_ = NONE;
+};
+
+}  // namespace drivers