image: properly differentiate cover types

- If we could find an embedded cover, then we can treat it as a
per-song cover
- Otherwise, just do our old album-based behavior.

app/src/main/java/org/oxycblt/auxio/image/extractor/Components.kt

@@ -27,7 +27,7 @@ import javax.inject.Inject
 
 class CoverKeyer @Inject constructor() : Keyer<Collection<Cover>> {
     override fun key(data: Collection<Cover>, options: Options) =
-        "${data.map { it.uniqueness }.hashCode()}"
+        "${data.map { it.key }.hashCode()}"
 }
 
 class CoverFetcher

app/src/main/java/org/oxycblt/auxio/image/extractor/Cover.kt

@@ -20,23 +20,28 @@ package org.oxycblt.auxio.image.extractor
 
 import android.net.Uri
 import org.oxycblt.auxio.list.sort.Sort
-import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.Song
 
-/**
- * Bundle of [Uri] information used in [CoverExtractor] to ensure consistent [Uri] use when loading
- * images.
- *
- * @param mediaStoreUri The album cover [Uri] obtained from MediaStore.
- * @param song The [Uri] of the first song (by track) of the album, which can also be used to obtain
- *   an album cover.
- * @author Alexander Capehart (OxygenCobalt)
- */
-data class Cover(val uniqueness: Uniqueness?, val mediaStoreUri: Uri, val songUri: Uri) {
-    sealed interface Uniqueness {
-        data class PerceptualHash(val perceptualHash: String) : Uniqueness
+sealed interface Cover {
+    val key: String
+    val mediaStoreCoverUri: Uri
 
-        data class UID(val uid: Music.UID) : Uniqueness
+    /**
+     * The song has an embedded cover art we support, so we can operate with it on a per-song
+     * basis.
+     */
+    data class Embedded(val songCoverUri: Uri, val songUri: Uri, val perceptualHash: String) : Cover {
+        override val mediaStoreCoverUri = songCoverUri
+        override val key = perceptualHash
+    }
+
+    /**
+     * We couldn't find any embedded cover art ourselves, but the android system might have some
+     * through a cover.jpg file or something similar.
+     */
+    data class External(val albumCoverUri: Uri) : Cover {
+        override val mediaStoreCoverUri = albumCoverUri
+        override val key = albumCoverUri.toString()
     }
 
     companion object {
@@ -45,7 +50,7 @@ data class Cover(val uniqueness: Uniqueness?, val mediaStoreUri: Uri, val songUr
         fun order(songs: Collection<Song>) =
             FALLBACK_SORT.songs(songs)
                 .map { it.cover }
-                .groupBy { it.uniqueness }
+                .groupBy { it.key }
                 .entries
                 .sortedByDescending { it.value.size }
                 .map { it.value.first() }

app/src/main/java/org/oxycblt/auxio/image/extractor/CoverExtractor.kt

@@ -140,21 +140,28 @@ constructor(
 
     private suspend fun openCoverInputStream(cover: Cover) =
         try {
-            when (imageSettings.coverMode) {
-                CoverMode.OFF -> null
-                CoverMode.MEDIA_STORE -> extractMediaStoreCover(cover)
-                CoverMode.QUALITY -> extractQualityCover(cover)
+            when (cover) {
+                is Cover.Embedded ->
+                    when (imageSettings.coverMode) {
+                        CoverMode.OFF -> null
+                        CoverMode.MEDIA_STORE -> extractMediaStoreCover(cover)
+                        CoverMode.QUALITY -> extractQualityCover(cover)
+                    }
+
+                is Cover.External -> {
+                    extractMediaStoreCover(cover)
+                }
             }
         } catch (e: Exception) {
             logE("Unable to extract album cover due to an error: $e")
             null
         }
 
-    private suspend fun extractQualityCover(cover: Cover) =
+    private suspend fun extractQualityCover(cover: Cover.Embedded) =
         extractAospMetadataCover(cover)
             ?: extractExoplayerCover(cover) ?: extractMediaStoreCover(cover)
 
-    private fun extractAospMetadataCover(cover: Cover): InputStream? =
+    private fun extractAospMetadataCover(cover: Cover.Embedded): InputStream? =
         MediaMetadataRetriever().run {
             // This call is time-consuming but it also doesn't seem to hold up the main thread,
             // so it's probably fine not to wrap it.rmt
@@ -166,7 +173,7 @@ constructor(
             embeddedPicture?.let { ByteArrayInputStream(it) }.also { release() }
         }
 
-    private suspend fun extractExoplayerCover(cover: Cover): InputStream? {
+    private suspend fun extractExoplayerCover(cover: Cover.Embedded): InputStream? {
         val tracks =
             MetadataRetriever.retrieveMetadata(mediaSourceFactory, MediaItem.fromUri(cover.songUri))
                 .asDeferred()
@@ -186,7 +193,7 @@ constructor(
 
     private suspend fun extractMediaStoreCover(cover: Cover) =
         // Eliminate any chance that this blocking call might mess up the loading process
-        withContext(Dispatchers.IO) { context.contentResolver.openInputStream(cover.mediaStoreUri) }
+        withContext(Dispatchers.IO) { context.contentResolver.openInputStream(cover.mediaStoreCoverUri) }
 
     /** Derived from phonograph: https://github.com/kabouzeid/Phonograph */
     private suspend fun createMosaic(streams: List<InputStream>, size: Size): FetchResult {

app/src/main/java/org/oxycblt/auxio/music/device/DeviceMusicImpl.kt

@@ -15,7 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
- 
+
 package org.oxycblt.auxio.music.device
 
 import org.oxycblt.auxio.R
@@ -29,8 +29,9 @@ import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicType
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.music.fs.MimeType
+import org.oxycblt.auxio.music.fs.toAlbumCoverUri
 import org.oxycblt.auxio.music.fs.toAudioUri
-import org.oxycblt.auxio.music.fs.toCoverUri
+import org.oxycblt.auxio.music.fs.toSongCoverUri
 import org.oxycblt.auxio.music.info.Date
 import org.oxycblt.auxio.music.info.Disc
 import org.oxycblt.auxio.music.info.Name
@@ -76,7 +77,8 @@ class SongImpl(
     override val name =
         nameFactory.parse(
             requireNotNull(rawSong.name) { "Invalid raw ${rawSong.path}: No title" },
-            rawSong.sortName)
+            rawSong.sortName
+        )
 
     override val track = rawSong.track
     override val disc = rawSong.disc?.let { Disc(it, rawSong.subtitle) }
@@ -114,11 +116,20 @@ class SongImpl(
         get() = _genres
 
     override val cover =
-        Cover(
-            rawSong.coverPerceptualHash?.let { Cover.Uniqueness.PerceptualHash(it) }
-                ?: Cover.Uniqueness.UID(uid),
-            requireNotNull(rawSong.mediaStoreId).toCoverUri(),
-            uri)
+        rawSong.coverPerceptualHash?.let {
+            // We were able to confirm that the song had a parsable cover and can be used on
+            // a per-song basis. Otherwise, just fall back to a per-album cover instead, as
+            // it implies either a cover.jpg pattern is used (likely) or ExoPlayer does not
+            // support the cover metadata of a given spec (unlikely).
+            Cover.Embedded(
+                requireNotNull(rawSong.mediaStoreId) { "Invalid raw ${rawSong.path}: No id" }.toSongCoverUri(),
+                uid,
+                it
+            )
+        }
+            ?: Cover.External(
+                requireNotNull(rawSong.albumMediaStoreId).toAlbumCoverUri()
+            )
 
     /**
      * The [RawAlbum] instances collated by the [Song]. This can be used to group [Song]s into an

app/src/main/java/org/oxycblt/auxio/music/fs/StorageUtil.kt

@@ -102,13 +102,15 @@ fun Long.toAudioUri() =
  * @return An external storage image [Uri]. May not exist.
  * @see ContentUris.withAppendedId
  */
-fun Long.toCoverUri(): Uri =
+fun Long.toSongCoverUri(): Uri =
     MediaStore.Audio.Media.EXTERNAL_CONTENT_URI.buildUpon().run {
-        appendPath(this@toCoverUri.toString())
+        appendPath(this@toSongCoverUri.toString())
         appendPath("albumart")
         build()
     }
 
+fun Long.toAlbumCoverUri(): Uri = ContentUris.withAppendedId(externalCoversUri, this)
+
 // --- STORAGEMANAGER UTILITIES ---
 // Largely derived from Material Files: https://github.com/zhanghai/MaterialFiles