music: make playlist uids random

Make playlist UIDs randomly generated.

This will allow multiple playlists with the same name, which may be
useful.

app/src/main/java/org/oxycblt/auxio/music/Music.kt

@@ -22,7 +22,6 @@ import android.content.Context
 import android.net.Uri
 import android.os.Parcelable
 import androidx.room.TypeConverter
-import java.security.MessageDigest
 import java.text.CollationKey
 import java.text.Collator
 import java.util.UUID
@@ -147,47 +146,13 @@ sealed interface Music : Item {
 
         companion object {
             /**
-             * Creates an Auxio-style [UID] with a [UUID] composed of a hash of the non-subjective,
-             * unlikely-to-change metadata of the music.
+             * Creates an Auxio-style [UID] with a [UUID] generated by internal Auxio code.
              *
              * @param mode The analogous [MusicMode] of the item that created this [UID].
-             * @param updates Block to update the [MessageDigest] hash with the metadata of the
-             *   item. Make sure the metadata hashed semantically aligns with the format
-             *   specification.
+             * @param uuid The generated [UUID] for this item.
              * @return A new auxio-style [UID].
              */
-            fun auxio(mode: MusicMode, updates: MessageDigest.() -> Unit): UID {
-                val digest =
-                    MessageDigest.getInstance("SHA-256").run {
-                        updates()
-                        digest()
-                    }
-                // Convert the digest to a UUID. This does cleave off some of the hash, but this
-                // is considered okay.
-                val uuid =
-                    UUID(
-                        digest[0]
-                            .toLong()
-                            .shl(56)
-                            .or(digest[1].toLong().and(0xFF).shl(48))
-                            .or(digest[2].toLong().and(0xFF).shl(40))
-                            .or(digest[3].toLong().and(0xFF).shl(32))
-                            .or(digest[4].toLong().and(0xFF).shl(24))
-                            .or(digest[5].toLong().and(0xFF).shl(16))
-                            .or(digest[6].toLong().and(0xFF).shl(8))
-                            .or(digest[7].toLong().and(0xFF)),
-                        digest[8]
-                            .toLong()
-                            .shl(56)
-                            .or(digest[9].toLong().and(0xFF).shl(48))
-                            .or(digest[10].toLong().and(0xFF).shl(40))
-                            .or(digest[11].toLong().and(0xFF).shl(32))
-                            .or(digest[12].toLong().and(0xFF).shl(24))
-                            .or(digest[13].toLong().and(0xFF).shl(16))
-                            .or(digest[14].toLong().and(0xFF).shl(8))
-                            .or(digest[15].toLong().and(0xFF)))
-                return UID(Format.AUXIO, mode, uuid)
-            }
+            fun auxio(mode: MusicMode, uuid: UUID) = UID(Format.AUXIO, mode, uuid)
 
             /**
              * Creates a MusicBrainz-style [UID] with a [UUID] derived from the MusicBrainz ID
@@ -198,7 +163,7 @@ sealed interface Music : Item {
              *   file.
              * @return A new MusicBrainz-style [UID].
              */
-            fun musicBrainz(mode: MusicMode, mbid: UUID): UID = UID(Format.MUSICBRAINZ, mode, mbid)
+            fun musicBrainz(mode: MusicMode, mbid: UUID) = UID(Format.MUSICBRAINZ, mode, mbid)
 
             /**
              * Convert a [UID]'s string representation back into a concrete [UID] instance.

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

@@ -32,8 +32,8 @@ import org.oxycblt.auxio.util.logD
  * Organized music library information obtained from device storage.
  *
  * This class allows for the creation of a well-formed music library graph from raw song
- * information. It's generally not expected to create this yourself and instead use
- * [MusicRepository].
+ * information. Instances are immutable. It's generally not expected to create this yourself and
+ * instead use [MusicRepository].
  *
  * @author Alexander Capehart
  */

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

@@ -21,6 +21,7 @@ package org.oxycblt.auxio.music.device
 import android.content.Context
 import androidx.annotation.VisibleForTesting
 import java.security.MessageDigest
+import java.util.*
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.list.Sort
 import org.oxycblt.auxio.music.*
@@ -48,7 +49,7 @@ class SongImpl(rawSong: RawSong, musicSettings: MusicSettings) : Song {
     override val uid =
         // Attempt to use a MusicBrainz ID first before falling back to a hashed UID.
         rawSong.musicBrainzId?.toUuidOrNull()?.let { Music.UID.musicBrainz(MusicMode.SONGS, it) }
-            ?: Music.UID.auxio(MusicMode.SONGS) {
+            ?: createHashedUid(MusicMode.SONGS) {
                 // Song UIDs are based on the raw data without parsing so that they remain
                 // consistent across music setting changes. Parents are not held up to the
                 // same standard since grouping is already inherently linked to settings.
@@ -231,7 +232,7 @@ class AlbumImpl(
     override val uid =
         // Attempt to use a MusicBrainz ID first before falling back to a hashed UID.
         rawAlbum.musicBrainzId?.let { Music.UID.musicBrainz(MusicMode.ALBUMS, it) }
-            ?: Music.UID.auxio(MusicMode.ALBUMS) {
+            ?: createHashedUid(MusicMode.ALBUMS) {
                 // Hash based on only names despite the presence of a date to increase stability.
                 // I don't know if there is any situation where an artist will have two albums with
                 // the exact same name, but if there is, I would love to know.
@@ -330,7 +331,7 @@ class ArtistImpl(
     override val uid =
         // Attempt to use a MusicBrainz ID first before falling back to a hashed UID.
         rawArtist.musicBrainzId?.let { Music.UID.musicBrainz(MusicMode.ARTISTS, it) }
-            ?: Music.UID.auxio(MusicMode.ARTISTS) { update(rawArtist.name) }
+            ?: createHashedUid(MusicMode.ARTISTS) { update(rawArtist.name) }
     override val rawName = rawArtist.name
     override val rawSortName = rawArtist.sortName
     override val sortName = (rawSortName ?: rawName)?.let { SortName(it, musicSettings) }
@@ -415,7 +416,7 @@ class GenreImpl(
     musicSettings: MusicSettings,
     override val songs: List<SongImpl>
 ) : Genre {
-    override val uid = Music.UID.auxio(MusicMode.GENRES) { update(rawGenre.name) }
+    override val uid = createHashedUid(MusicMode.GENRES) { update(rawGenre.name) }
     override val rawName = rawGenre.name
     override val rawSortName = rawName
     override val sortName = (rawSortName ?: rawName)?.let { SortName(it, musicSettings) }
@@ -473,6 +474,48 @@ class GenreImpl(
     }
 }
 
+/**
+ * Generate a [Music.UID] derived from the hash of objective music metadata.
+ *
+ * @param mode The analogous [MusicMode] of the item that created this [UID].
+ * @param updates Block to update the [MessageDigest] hash with the metadata of the item. Make sure
+ *   the metadata hashed semantically aligns with the format specification.
+ * @return A new [Music.UID] of Auxio format whose [UUID] was derived from the SHA-256 hash of the
+ *   metadata given.
+ */
+fun createHashedUid(mode: MusicMode, updates: MessageDigest.() -> Unit): Music.UID {
+    val digest =
+        MessageDigest.getInstance("SHA-256").run {
+            updates()
+            digest()
+        }
+    // Convert the digest to a UUID. This does cleave off some of the hash, but this
+    // is considered okay.
+    val uuid =
+        UUID(
+            digest[0]
+                .toLong()
+                .shl(56)
+                .or(digest[1].toLong().and(0xFF).shl(48))
+                .or(digest[2].toLong().and(0xFF).shl(40))
+                .or(digest[3].toLong().and(0xFF).shl(32))
+                .or(digest[4].toLong().and(0xFF).shl(24))
+                .or(digest[5].toLong().and(0xFF).shl(16))
+                .or(digest[6].toLong().and(0xFF).shl(8))
+                .or(digest[7].toLong().and(0xFF)),
+            digest[8]
+                .toLong()
+                .shl(56)
+                .or(digest[9].toLong().and(0xFF).shl(48))
+                .or(digest[10].toLong().and(0xFF).shl(40))
+                .or(digest[11].toLong().and(0xFF).shl(32))
+                .or(digest[12].toLong().and(0xFF).shl(24))
+                .or(digest[13].toLong().and(0xFF).shl(16))
+                .or(digest[14].toLong().and(0xFF).shl(8))
+                .or(digest[15].toLong().and(0xFF)))
+    return Music.UID.auxio(mode, uuid)
+}
+
 /**
  * Update a [MessageDigest] with a lowercase [String].
  *

app/src/main/java/org/oxycblt/auxio/music/user/PlaylistImpl.kt

@@ -19,20 +19,36 @@
 package org.oxycblt.auxio.music.user
 
 import android.content.Context
+import java.util.*
 import org.oxycblt.auxio.music.*
 import org.oxycblt.auxio.music.device.DeviceLibrary
 
-class PlaylistImpl(
+class PlaylistImpl
+private constructor(
+    override val uid: Music.UID,
+    override val rawName: String,
+    override val songs: List<Song>,
+    musicSettings: MusicSettings
+) : Playlist {
+    constructor(
+        name: String,
+        songs: List<Song>,
+        musicSettings: MusicSettings
+    ) : this(Music.UID.auxio(MusicMode.PLAYLISTS, UUID.randomUUID()), name, songs, musicSettings)
+
+    constructor(
         rawPlaylist: RawPlaylist,
         deviceLibrary: DeviceLibrary,
         musicSettings: MusicSettings
-) : Playlist {
-    override val uid = rawPlaylist.playlistInfo.playlistUid
-    override val rawName = rawPlaylist.playlistInfo.name
+    ) : this(
+        rawPlaylist.playlistInfo.playlistUid,
+        rawPlaylist.playlistInfo.name,
+        rawPlaylist.songs.mapNotNull { deviceLibrary.findSong(it.songUid) },
+        musicSettings)
+
     override fun resolveName(context: Context) = rawName
     override val rawSortName = null
     override val sortName = SortName(rawName, musicSettings)
-    override val songs = rawPlaylist.songs.mapNotNull { deviceLibrary.findSong(it.songUid) }
     override val durationMs = songs.sumOf { it.durationMs }
     override val albums =
         songs.groupBy { it.album }.entries.sortedByDescending { it.value.size }.map { it.key }

app/src/main/java/org/oxycblt/auxio/music/user/UserLibrary.kt

@@ -20,10 +20,7 @@ package org.oxycblt.auxio.music.user
 
 import javax.inject.Inject
 import kotlinx.coroutines.channels.Channel
-import org.oxycblt.auxio.music.Music
-import org.oxycblt.auxio.music.MusicMode
-import org.oxycblt.auxio.music.MusicSettings
-import org.oxycblt.auxio.music.Playlist
+import org.oxycblt.auxio.music.*
 import org.oxycblt.auxio.music.device.DeviceLibrary
 
 /**
@@ -54,6 +51,7 @@ interface UserLibrary {
          *
          * @param deviceLibrary Asynchronously populated [DeviceLibrary] that can be obtained later.
          *   This allows database information to be read before the actual instance is constructed.
+         * @return A new [UserLibrary] with the required implementation.
          */
         suspend fun read(deviceLibrary: Channel<DeviceLibrary>): UserLibrary
     }
@@ -77,15 +75,8 @@ private class UserLibraryImpl(
         get() = playlistMap.values.toList()
 
     init {
-        val uid = Music.UID.auxio(MusicMode.PLAYLISTS) { update("Playlist 1".toByteArray()) }
-        playlistMap[uid] =
-            PlaylistImpl(
-                RawPlaylist(
-                    PlaylistInfo(uid, "Playlist 1"),
-                    deviceLibrary.songs.slice(10..30).map { PlaylistSong(it.uid) }),
-                deviceLibrary,
-                musicSettings,
-            )
+        val playlist = PlaylistImpl("Playlist 1", deviceLibrary.songs.slice(58..100), musicSettings)
+        playlistMap[playlist.uid] = playlist
     }
 
     override fun findPlaylist(uid: Music.UID) = playlistMap[uid]