1 files changed, 307 insertions, 0 deletions
diff --git a/src/tangara/database/track.cpp b/src/tangara/database/track.cpp
new file mode 100644
index 00000000..1b1442a1
--- /dev/null
+++ b/src/tangara/database/track.cpp
@@ -0,0 +1,307 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "track.hpp"
+
+#include <iomanip>
+#include <iostream>
+#include <memory_resource>
+#include <span>
+#include <sstream>
+#include <string>
+
+#include "esp_log.h"
+#include "komihash.h"
+
+#include "memory_resource.hpp"
+
+namespace database {
+
+static constexpr char kGenreDelimiters[] = ",;";
+
+auto tagName(Tag t) -> std::string {
+  switch (t) {
+    case Tag::kTitle:
+      return "title";
+    case Tag::kArtist:
+      return "artist";
+    case Tag::kAlbum:
+      return "album";
+    case Tag::kAlbumArtist:
+      return "album_artist";
+    case Tag::kDisc:
+      return "disc";
+    case Tag::kTrack:
+      return "track";
+    case Tag::kAlbumOrder:
+      return "album_order";
+    case Tag::kGenres:
+      return "genre";
+  }
+  return "";
+}
+
+auto tagHash(const TagValue& t) -> uint64_t {
+  return std::visit(
+      [&](auto&& arg) {
+        using T = std::decay_t<decltype(arg)>;
+        if constexpr (std::is_same_v<T, std::monostate>) {
+          return static_cast<uint64_t>(0);
+        } else if constexpr (std::is_same_v<T, std::pmr::string>) {
+          return komihash(arg.data(), arg.size(), 0);
+        } else if constexpr (std::is_same_v<T, uint32_t>) {
+          return komihash(&arg, sizeof(arg), 0);
+        } else if constexpr (std::is_same_v<
+                                 T, std::span<const std::pmr::string>>) {
+          komihash_stream_t hash;
+          komihash_stream_init(&hash, 0);
+          for (const auto& i : arg) {
+            komihash_stream_update(&hash, i.data(), i.size());
+          }
+          return komihash_stream_final(&hash);
+        }
+      },
+      t);
+  return 0;
+}
+
+auto tagToString(const TagValue& val) -> std::string {
+  return std::visit(
+      [&](auto&& arg) -> std::string {
+        using T = std::decay_t<decltype(arg)>;
+        if constexpr (std::is_same_v<T, std::monostate>) {
+          return "";
+        } else if constexpr (std::is_same_v<T, std::pmr::string>) {
+          return {arg.data(), arg.size()};
+        } else if constexpr (std::is_same_v<T, uint32_t>) {
+          return std::to_string(arg);
+        } else if constexpr (std::is_same_v<
+                                 T, std::span<const std::pmr::string>>) {
+          std::ostringstream builder{};
+          for (const auto& str : arg) {
+            builder << std::string{str.data(), str.size()} << ",";
+          }
+          return builder.str();
+        }
+      },
+      val);
+  return "";
+}
+
+auto TrackTags::create() -> std::shared_ptr<TrackTags> {
+  return std::allocate_shared<TrackTags,
+                              std::pmr::polymorphic_allocator<TrackTags>>(
+      &memory::kSpiRamResource);
+}
+
+template <typename T>
+auto valueOrMonostate(std::optional<T> t) -> TagValue {
+  if (t) {
+    return *t;
+  }
+  return std::monostate{};
+}
+
+auto TrackTags::get(Tag t) const -> TagValue {
+  switch (t) {
+    case Tag::kTitle:
+      return valueOrMonostate(title_);
+    case Tag::kArtist:
+      return valueOrMonostate(artist_);
+    case Tag::kAlbum:
+      return valueOrMonostate(album_);
+    case Tag::kAlbumArtist:
+      return valueOrMonostate(album_artist_);
+    case Tag::kDisc:
+      return valueOrMonostate(disc_);
+    case Tag::kTrack:
+      return valueOrMonostate(track_);
+    case Tag::kAlbumOrder:
+      return albumOrder();
+    case Tag::kGenres:
+      return genres_;
+  }
+  return std::monostate{};
+}
+
+auto TrackTags::set(Tag t, std::string_view v) -> void {
+  switch (t) {
+    case Tag::kTitle:
+      title(v);
+      break;
+    case Tag::kArtist:
+      artist(v);
+      break;
+    case Tag::kAlbum:
+      album(v);
+      break;
+    case Tag::kAlbumArtist:
+      albumArtist(v);
+      break;
+    case Tag::kDisc:
+      disc(v);
+      break;
+    case Tag::kTrack:
+      track(v);
+      break;
+    case Tag::kAlbumOrder:
+      // This tag is derices from disc and track, and so it can't be set.
+      break;
+    case Tag::kGenres:
+      genres(v);
+      break;
+  }
+}
+
+auto TrackTags::allPresent() const -> std::vector<Tag> {
+  std::vector<Tag> out;
+  auto add_if_present = [&](Tag t, auto opt) {
+    if (opt) {
+      out.push_back(t);
+    }
+  };
+  add_if_present(Tag::kTitle, title_);
+  add_if_present(Tag::kArtist, artist_);
+  add_if_present(Tag::kAlbum, album_);
+  add_if_present(Tag::kAlbumArtist, album_artist_);
+  add_if_present(Tag::kDisc, disc_);
+  add_if_present(Tag::kTrack, track_);
+  add_if_present(Tag::kGenres, !genres_.empty());
+  return out;
+}
+
+auto TrackTags::title() const -> const std::optional<std::pmr::string>& {
+  return title_;
+}
+
+auto TrackTags::title(std::string_view s) -> void {
+  title_ = s;
+}
+
+auto TrackTags::artist() const -> const std::optional<std::pmr::string>& {
+  return artist_;
+}
+
+auto TrackTags::artist(std::string_view s) -> void {
+  artist_ = s;
+}
+
+auto TrackTags::album() const -> const std::optional<std::pmr::string>& {
+  return album_;
+}
+
+auto TrackTags::album(std::string_view s) -> void {
+  album_ = s;
+}
+
+auto TrackTags::albumArtist() const -> const std::optional<std::pmr::string>& {
+  return album_artist_;
+}
+
+auto TrackTags::albumArtist(std::string_view s) -> void {
+  album_artist_ = s;
+}
+
+auto TrackTags::disc() const -> const std::optional<uint8_t>& {
+  return disc_;
+}
+
+auto TrackTags::disc(const std::string_view s) -> void {
+  disc_ = std::strtol(s.data(), nullptr, 10);
+}
+
+auto TrackTags::track() const -> const std::optional<uint16_t>& {
+  return track_;
+}
+
+auto TrackTags::track(const std::string_view s) -> void {
+  track_ = std::strtol(s.data(), nullptr, 10);
+}
+
+auto TrackTags::albumOrder() const -> uint32_t {
+  return (disc_.value_or(0) << 16) | track_.value_or(0);
+}
+
+auto TrackTags::genres() const -> std::span<const std::pmr::string> {
+  return genres_;
+}
+
+auto TrackTags::genres(const std::string_view s) -> void {
+  genres_.clear();
+  std::string src = {s.data(), s.size()};
+  char* token = std::strtok(src.data(), kGenreDelimiters);
+
+  auto trim_and_add = [this](std::string_view s) {
+    std::string copy = {s.data(), s.size()};
+
+    // Trim the left
+    copy.erase(copy.begin(),
+               std::find_if(copy.begin(), copy.end(), [](unsigned char ch) {
+                 return !std::isspace(ch);
+               }));
+
+    // Trim the right
+    copy.erase(std::find_if(copy.rbegin(), copy.rend(),
+                            [](unsigned char ch) { return !std::isspace(ch); })
+                   .base(),
+               copy.end());
+
+    // Ignore empty strings.
+    if (!copy.empty()) {
+      genres_.push_back({copy.data(), copy.size()});
+    }
+  };
+
+  if (token == NULL) {
+    // No delimiters found in the input. Treat this as a single genre.
+    trim_and_add(s);
+  } else {
+    while (token != NULL) {
+      // Add tokens until no more delimiters found.
+      trim_and_add(token);
+      token = std::strtok(NULL, kGenreDelimiters);
+    }
+  }
+}
+
+/*
+ * Uses a komihash stream to incrementally hash tags. This lowers the
+ * function's memory footprint a little so that it's safe to call from any
+ * stack.
+ */
+auto TrackTags::Hash() const -> uint64_t {
+  // TODO(jacqueline): this function doesn't work very well for tracks with no
+  // tags at all.
+  komihash_stream_t stream;
+  komihash_stream_init(&stream, 0);
+
+  auto add = [&](const uint64_t& h) {
+    komihash_stream_update(&stream, &h, sizeof(h));
+  };
+
+  add(tagHash(get(Tag::kTitle)));
+  add(tagHash(get(Tag::kArtist)));
+  add(tagHash(get(Tag::kAlbum)));
+  add(tagHash(get(Tag::kAlbumArtist)));
+
+  // TODO: Should we be including this?
+  add(tagHash(get(Tag::kAlbumOrder)));
+
+  return komihash_stream_final(&stream);
+}
+
+auto Track::TitleOrFilename() const -> std::pmr::string {
+  auto title = tags().title();
+  if (title) {
+    return *title;
+  }
+  auto start = data().filepath.find_last_of('/');
+  if (start == std::pmr::string::npos) {
+    return data().filepath;
+  }
+  return data().filepath.substr(start + 1);
+}
+}  // namespace database