music: update hashing

Update id hashing to correctly handle null artists and take discs
and durations into account.

Note that we try not to hash values only obtained with the ExoPlayer
parser, as those could feasibly change if the setting was toggled,
thus causing the playback state to wipe.

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

@@ -112,10 +112,10 @@ data class Song(
         get() {
             var result = rawName.hashCode().toLong()
             result = 31 * result + album.rawName.hashCode()
-            result = 31 * result + album.artist.rawName.hashCode()
+            result = 31 * result + (album.artist.rawName ?: MediaStore.UNKNOWN_STRING).hashCode()
             result = 31 * result + (track ?: 0)
-            // TODO: Rework hashing to add discs and handle null values correctly
-            result = 31 * result + durationMs.hashCode()
+            result = 31 * result + (disc ?: 0)
+            result = 31 * result + durationMs
             return result
         }
 
@@ -160,7 +160,7 @@ data class Song(
 
     /** Internal field. Do not use. */
     val _genreGroupingId: Long
-        get() = (_genreName ?: MediaStore.UNKNOWN_STRING).hashCode().toLong()
+        get() = (_genreName?.lowercase() ?: MediaStore.UNKNOWN_STRING).hashCode().toLong()
 
     /** Internal field. Do not use. */
     val _artistGroupingName: String?
@@ -220,7 +220,7 @@ data class Album(
     override val id: Long
         get() {
             var result = rawName.hashCode().toLong()
-            result = 31 * result + artist.rawName.hashCode()
+            result = 31 * result + (artist.rawName ?: MediaStore.UNKNOWN_STRING).hashCode()
             result = 31 * result + (date?.year ?: 0)
             return result
         }
@@ -292,9 +292,9 @@ data class Genre(override val rawName: String?, override val songs: List<Song>)
 /**
  * An ISO-8601/RFC 3339 Date.
  *
- * Unlike a typical Date within the standard library, this class is simply a 1:1 mapping between the
- * tag date format of ID3v2 and (presumably) the Vorbis date format, implementing only format
- * validation and excluding advanced or locale-specific date functionality..
+ * Unlike a typical Date within the standard library, this class just represents the ID3v2/Vorbis
+ * date format, which is largely assumed to be a subset of ISO-8601. No validation outside of
+ * format validation is done.
  *
  * The reasoning behind Date is that Auxio cannot trust any kind of metadata date to actually make
  * sense in a calendar, due to bad tagging, locale-specific issues, or simply from the limited
@@ -305,7 +305,7 @@ data class Genre(override val rawName: String?, override val songs: List<Song>)
  * [fromYear] or [parseTimestamp]. The string representation of a Date is RFC 3339, with granular
  * position depending on the presence of particular tokens.
  *
- * Please, *Do not use this for anything important related to time.* I cannot stress this enough.
+ * Please, **Do not use this for anything important related to time.** I cannot stress this enough.
  * This class will blow up if you try to do that.
  *
  * @author OxygenCobalt
@@ -327,6 +327,9 @@ class Date private constructor(private val tokens: List<Int>) : Comparable<Date>
     val year: Int
         get() = tokens[0]
 
+    /** Resolve the year field in a way suitable for the UI. */
+    fun resolveYear(context: Context) = context.getString(R.string.fmt_number, year)
+
     private val month: Int?
         get() = tokens.getOrNull(1)
 
@@ -342,7 +345,6 @@ class Date private constructor(private val tokens: List<Int>) : Comparable<Date>
     private val second: Int?
         get() = tokens.getOrNull(5)
 
-    fun resolveYear(context: Context) = context.getString(R.string.fmt_number, year)
 
     override fun hashCode() = tokens.hashCode()
 

app/src/main/java/org/oxycblt/auxio/playback/state/PlaybackStateDatabase.kt

@@ -307,7 +307,7 @@ class PlaybackStateDatabase private constructor(context: Context) :
         const val COLUMN_INDEX = "queue_index"
         const val COLUMN_PLAYBACK_MODE = "playback_mode"
         const val COLUMN_IS_SHUFFLED = "is_shuffling"
-        const val COLUMN_REPEAT_MODE = "loop_mode"
+        const val COLUMN_REPEAT_MODE = "repeat_mode"
     }
 
     private object QueueColumns {
@@ -318,7 +318,7 @@ class PlaybackStateDatabase private constructor(context: Context) :
 
     companion object {
         const val DB_NAME = "auxio_state_database.db"
-        const val DB_VERSION = 6
+        const val DB_VERSION = 7
 
         const val TABLE_NAME_STATE = "playback_state_table"
         const val TABLE_NAME_QUEUE = "queue_table"