musikr: re-connect cover to model

app/src/main/java/org/oxycblt/auxio/image/CoverView.kt

@@ -374,7 +374,7 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
     fun bind(songs: List<Song>, desc: String, @DrawableRes errorRes: Int) =
         bindImpl(Cover.multi(songs), desc, errorRes)
 
-    private fun bindImpl(cover: Cover, desc: String, @DrawableRes errorRes: Int) {
+    private fun bindImpl(cover: Cover?, desc: String, @DrawableRes errorRes: Int) {
         val request =
             ImageRequest.Builder(context)
                 .data(cover)

app/src/main/java/org/oxycblt/musikr/Music.kt

@@ -265,7 +265,7 @@ interface Song : Music {
     /** The date the audio file was added to the device, as a unix epoch timestamp. */
     val dateAdded: Long
     /** Useful information to quickly obtain the album cover. */
-    val cover: Cover.Single
+    val cover: Cover.Single?
     /**
      * The parent [Album]. If the metadata did not specify an album, it's parent directory is used
      * instead.

app/src/main/java/org/oxycblt/musikr/cache/Cache.kt

@@ -34,7 +34,7 @@ interface Cache {
     }
 }
 
-data class CachedSong(val parsedTags: ParsedTags, val cover: Cover?)
+data class CachedSong(val parsedTags: ParsedTags, val cover: Cover.Single?)
 
 private class FullCache(private val cacheInfoDao: CacheInfoDao) : Cache {
     override suspend fun read(file: DeviceFile) =

app/src/main/java/org/oxycblt/musikr/cache/CacheDatabase.kt

@@ -88,7 +88,7 @@ internal data class CachedInfo(
     val albumArtistNames: List<String>,
     val albumArtistSortNames: List<String>,
     val genreNames: List<String>,
-    val cover: Cover? = null
+    val cover: Cover.Single? = null
 ) {
     fun intoCachedSong() =
         CachedSong(
@@ -128,7 +128,7 @@ internal data class CachedInfo(
 
         @TypeConverter fun toDate(string: String?) = string?.let(Date::from)
 
-        @TypeConverter fun fromCover(cover: Cover?) = cover?.key
+        @TypeConverter fun fromCover(cover: Cover.Single?) = cover?.key
 
         @TypeConverter fun toCover(key: String?) = key?.let { Cover.Single(it) }
     }

app/src/main/java/org/oxycblt/musikr/cover/Cover.kt

@@ -41,7 +41,7 @@ sealed interface Cover {
 
         private fun order(songs: Collection<Song>) =
             FALLBACK_SORT.songs(songs)
-                .map { it.cover }
+                .mapNotNull { it.cover }
                 .groupBy { it.key }
                 .entries
                 .sortedByDescending { it.value.size }

app/src/main/java/org/oxycblt/musikr/model/SongImpl.kt

@@ -22,7 +22,6 @@ import org.oxycblt.musikr.Album
 import org.oxycblt.musikr.Artist
 import org.oxycblt.musikr.Genre
 import org.oxycblt.musikr.Song
-import org.oxycblt.musikr.cover.Cover
 import org.oxycblt.musikr.tag.interpret.PreSong
 
 interface SongCore {
@@ -56,7 +55,7 @@ class SongImpl(private val handle: SongCore) : Song {
     override val replayGainAdjustment = preSong.replayGainAdjustment
     override val lastModified = preSong.lastModified
     override val dateAdded = preSong.dateAdded
-    override val cover = Cover.single("")
+    override val cover = preSong.cover
     override val album: Album
         get() = handle.resolveAlbum()
 

app/src/main/java/org/oxycblt/musikr/pipeline/ExtractStep.kt

@@ -96,5 +96,6 @@ constructor(
 }
 
 sealed interface ExtractedMusic {
-    data class Song(val file: DeviceFile, val tags: ParsedTags, val cover: Cover?) : ExtractedMusic
+    data class Song(val file: DeviceFile, val tags: ParsedTags, val cover: Cover.Single?) :
+        ExtractedMusic
 }

app/src/main/java/org/oxycblt/musikr/tag/interpret/PreMusic.kt

@@ -48,7 +48,7 @@ data class PreSong(
     val replayGainAdjustment: ReplayGainAdjustment,
     val lastModified: Long,
     val dateAdded: Long,
-    val cover: Cover?,
+    val cover: Cover.Single?,
     val preAlbum: PreAlbum,
     val preArtists: List<PreArtist>,
     val preGenres: List<PreGenre>

app/src/main/java/org/oxycblt/musikr/tag/interpret/TagInterpreter.kt

@@ -36,7 +36,7 @@ interface TagInterpreter {
     fun interpret(
         file: DeviceFile,
         parsedTags: ParsedTags,
-        cover: Cover?,
+        cover: Cover.Single?,
         interpretation: Interpretation
     ): PreSong
 }
@@ -45,7 +45,7 @@ class TagInterpreterImpl @Inject constructor() : TagInterpreter {
     override fun interpret(
         file: DeviceFile,
         parsedTags: ParsedTags,
-        cover: Cover?,
+        cover: Cover.Single?,
         interpretation: Interpretation
     ): PreSong {
         val individualPreArtists =