music: handle numbers when sorting

Now sort by logical numeric order with music names.

This is a nice QoL improvement.

Resolves #394.

app/src/main/java/org/oxycblt/auxio/detail/AlbumDetailFragment.kt

@@ -52,9 +52,6 @@ import org.oxycblt.auxio.util.*
  * A [ListFragment] that shows information about an [Album].
  *
  * @author Alexander Capehart (OxygenCobalt)
- *
- * TODO: Split up list and header adapters, and then work from there. Header item works fine. Make
- *   sure that other pos-dependent code functions
  */
 @AndroidEntryPoint
 class AlbumDetailFragment :

app/src/main/java/org/oxycblt/auxio/home/list/AlbumListFragment.kt

@@ -94,11 +94,10 @@ class AlbumListFragment :
         // Change how we display the popup depending on the current sort mode.
         return when (homeModel.getSortForTab(MusicMode.ALBUMS).mode) {
             // By Name -> Use Name
-            is Sort.Mode.ByName -> album.collationKey?.run { sourceString.first().uppercase() }
+            is Sort.Mode.ByName -> album.sortName?.thumbString
 
             // By Artist -> Use name of first artist
-            is Sort.Mode.ByArtist ->
-                album.artists[0].collationKey?.run { sourceString.first().uppercase() }
+            is Sort.Mode.ByArtist -> album.artists[0].sortName?.thumbString
 
             // Date -> Use minimum date (Maximum dates are not sorted by, so showing them is odd)
             is Sort.Mode.ByDate -> album.dates?.run { min.resolveDate(requireContext()) }

app/src/main/java/org/oxycblt/auxio/home/list/ArtistListFragment.kt

@@ -93,7 +93,7 @@ class ArtistListFragment :
         // Change how we display the popup depending on the current sort mode.
         return when (homeModel.getSortForTab(MusicMode.ARTISTS).mode) {
             // By Name -> Use Name
-            is Sort.Mode.ByName -> artist.collationKey?.run { sourceString.first().uppercase() }
+            is Sort.Mode.ByName -> artist.sortName?.thumbString
 
             // Duration -> Use formatted duration
             is Sort.Mode.ByDuration -> artist.durationMs?.formatDurationMs(false)

app/src/main/java/org/oxycblt/auxio/home/list/GenreListFragment.kt

@@ -92,7 +92,7 @@ class GenreListFragment :
         // Change how we display the popup depending on the current sort mode.
         return when (homeModel.getSortForTab(MusicMode.GENRES).mode) {
             // By Name -> Use Name
-            is Sort.Mode.ByName -> genre.collationKey?.run { sourceString.first().uppercase() }
+            is Sort.Mode.ByName -> genre.sortName?.thumbString
 
             // Duration -> Use formatted duration
             is Sort.Mode.ByDuration -> genre.durationMs.formatDurationMs(false)

app/src/main/java/org/oxycblt/auxio/home/list/SongListFragment.kt

@@ -100,15 +100,13 @@ class SongListFragment :
         // based off the names of the parent objects and not the child objects.
         return when (homeModel.getSortForTab(MusicMode.SONGS).mode) {
             // Name -> Use name
-            is Sort.Mode.ByName -> song.collationKey?.run { sourceString.first().uppercase() }
+            is Sort.Mode.ByName -> song.sortName?.thumbString
 
             // Artist -> Use name of first artist
-            is Sort.Mode.ByArtist ->
-                song.album.artists[0].collationKey?.run { sourceString.first().uppercase() }
+            is Sort.Mode.ByArtist -> song.album.artists[0].sortName?.thumbString
 
             // Album -> Use Album Name
-            is Sort.Mode.ByAlbum ->
-                song.album.collationKey?.run { sourceString.first().uppercase() }
+            is Sort.Mode.ByAlbum -> song.album.sortName?.thumbString
 
             // Year -> Use Full Year
             is Sort.Mode.ByDate -> song.album.dates?.resolveDate(requireContext())

app/src/main/java/org/oxycblt/auxio/list/Sort.kt

@@ -203,7 +203,7 @@ data class Sort(val mode: Mode, val direction: Direction) {
         /**
          * Sort by the item's name.
          *
-         * @see Music.collationKey
+         * @see Music.sortName
          */
         object ByName : Mode() {
             override val intCode: Int
@@ -248,7 +248,7 @@ data class Sort(val mode: Mode, val direction: Direction) {
         /**
          * Sort by the [Artist] name of an item. Only available for [Song] and [Album].
          *
-         * @see Artist.collationKey
+         * @see Artist.sortName
          */
         object ByArtist : Mode() {
             override val intCode: Int
@@ -536,8 +536,8 @@ data class Sort(val mode: Mode, val direction: Direction) {
          */
         private class BasicComparator<T : Music> private constructor() : Comparator<T> {
             override fun compare(a: T, b: T): Int {
-                val aKey = a.collationKey
-                val bKey = b.collationKey
+                val aKey = a.sortName
+                val bKey = b.sortName
                 return when {
                     aKey != null && bKey != null -> aKey.compareTo(bKey)
                     aKey == null && bKey != null -> -1 // a < b

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

@@ -23,6 +23,7 @@ import android.net.Uri
 import android.os.Parcelable
 import java.security.MessageDigest
 import java.text.CollationKey
+import java.text.Collator
 import java.util.UUID
 import kotlin.math.max
 import kotlinx.parcelize.IgnoredOnParcel
@@ -34,6 +35,7 @@ import org.oxycblt.auxio.music.metadata.ReleaseType
 import org.oxycblt.auxio.music.storage.MimeType
 import org.oxycblt.auxio.music.storage.Path
 import org.oxycblt.auxio.util.concatLocalized
+import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.toUuidOrNull
 
 /**
@@ -74,15 +76,11 @@ sealed interface Music : Item {
     val rawSortName: String?
 
     /**
-     * A [CollationKey] derived from [rawName] and [rawSortName] that can be used to sort items in a
-     * semantically-correct manner. Will be null if the item has no name.
-     *
-     * The key will have the following attributes:
-     * - If [rawSortName] is present, this key will be derived from it. Otherwise [rawName] is used.
-     * - If the string begins with an article, such as "the", it will be stripped, as is usually
-     *   convention for sorting media. This is not internationalized.
+     * A black-box value derived from [rawSortName] and [rawName] that can be used for user-friendly
+     * sorting in the context of music. This should be preferred over [rawSortName] in most cases.
+     * Null if there are no [rawName] or [rawSortName] values to build on.
      */
-    val collationKey: CollationKey?
+    val sortName: SortName?
 
     /**
      * A unique identifier for a piece of music.
@@ -359,6 +357,78 @@ interface Genre : MusicParent {
     val durationMs: Long
 }
 
+/**
+ * A black-box datatype for a variation of music names that is suitable for music-oriented sorting.
+ * It will automatically handle articles like "The" and numeric components like "An".
+ * @author Alexander Capehart (OxygenCobalt)
+ */
+class SortName(name: String, musicSettings: MusicSettings) : Comparable<SortName> {
+    private val number: Int?
+    private val collationKey: CollationKey
+    val thumbString: String?
+
+    init {
+        var sortName = name
+        if (musicSettings.automaticSortNames) {
+            sortName =
+                sortName.run {
+                    when {
+                        length > 5 && startsWith("the ", ignoreCase = true) -> substring(4)
+                        length > 4 && startsWith("an ", ignoreCase = true) -> substring(3)
+                        length > 3 && startsWith("a ", ignoreCase = true) -> substring(2)
+                        else -> this
+                    }
+                }
+        }
+
+        // Parse out numeric portions of the title and use those for sorting, if applicable.
+        val numericEnd = sortName.indexOfFirst { !it.isDigit() }
+        when (numericEnd) {
+            // No numeric component.
+            0 -> number = null
+            // Whole title is numeric.
+            -1 -> {
+                number = sortName.toIntOrNull()
+                sortName = ""
+            }
+            // Part of the title is numeric.
+            else -> {
+                number = sortName.slice(0 until numericEnd).toIntOrNull()
+                sortName = sortName.slice(numericEnd until sortName.length)
+            }
+        }
+
+        collationKey = COLLATOR.getCollationKey(sortName)
+
+        // Keep track of a string to use in the thumb view.
+        // TODO: This needs to be moved elsewhere.
+        thumbString = (number?.toString() ?: collationKey?.run { sourceString.first().uppercase() })
+    }
+
+    override fun toString(): String = number?.toString() ?: collationKey.sourceString
+
+    override fun compareTo(other: SortName) =
+        when {
+            number != null && other.number != null -> number.compareTo(other.number)
+            number != null && other.number == null -> -1 // a < b
+            number == null && other.number != null -> 1 // a > b
+            else -> collationKey.compareTo(other.collationKey)
+        }
+
+    override fun equals(other: Any?) =
+        other is SortName && number == other.number && collationKey == other.collationKey
+
+    override fun hashCode(): Int {
+        var hashCode = collationKey.hashCode()
+        if (number != null) hashCode = 31 * hashCode + number
+        return hashCode
+    }
+
+    private companion object {
+        val COLLATOR: Collator = Collator.getInstance().apply { strength = Collator.PRIMARY }
+    }
+}
+
 /**
  * Run [Music.resolveName] on each instance in the given list and concatenate them into a [String]
  * in a localized manner.

app/src/main/java/org/oxycblt/auxio/music/model/MusicImpl.kt

@@ -21,17 +21,9 @@ package org.oxycblt.auxio.music.model
 import android.content.Context
 import androidx.annotation.VisibleForTesting
 import java.security.MessageDigest
-import java.text.CollationKey
-import java.text.Collator
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.list.Sort
-import org.oxycblt.auxio.music.Album
-import org.oxycblt.auxio.music.Artist
-import org.oxycblt.auxio.music.Genre
-import org.oxycblt.auxio.music.Music
-import org.oxycblt.auxio.music.MusicMode
-import org.oxycblt.auxio.music.MusicSettings
-import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.music.*
 import org.oxycblt.auxio.music.metadata.Date
 import org.oxycblt.auxio.music.metadata.Disc
 import org.oxycblt.auxio.music.metadata.ReleaseType
@@ -72,7 +64,7 @@ class SongImpl(rawSong: RawSong, musicSettings: MusicSettings) : Song {
             }
     override val rawName = requireNotNull(rawSong.name) { "Invalid raw: No title" }
     override val rawSortName = rawSong.sortName
-    override val collationKey = makeCollationKey(musicSettings)
+    override val sortName = SortName((rawSortName ?: rawName), musicSettings)
     override fun resolveName(context: Context) = rawName
 
     override val track = rawSong.track
@@ -248,7 +240,7 @@ class AlbumImpl(
             }
     override val rawName = rawAlbum.name
     override val rawSortName = rawAlbum.sortName
-    override val collationKey = makeCollationKey(musicSettings)
+    override val sortName = SortName((rawSortName ?: rawName), musicSettings)
     override fun resolveName(context: Context) = rawName
 
     override val dates = Date.Range.from(songs.mapNotNull { it.date })
@@ -341,7 +333,7 @@ class ArtistImpl(
             ?: Music.UID.auxio(MusicMode.ARTISTS) { update(rawArtist.name) }
     override val rawName = rawArtist.name
     override val rawSortName = rawArtist.sortName
-    override val collationKey = makeCollationKey(musicSettings)
+    override val sortName = (rawSortName ?: rawName)?.let { SortName(it, musicSettings) }
     override fun resolveName(context: Context) = rawName ?: context.getString(R.string.def_artist)
     override val songs: List<Song>
 
@@ -426,7 +418,7 @@ class GenreImpl(
     override val uid = Music.UID.auxio(MusicMode.GENRES) { update(rawGenre.name) }
     override val rawName = rawGenre.name
     override val rawSortName = rawName
-    override val collationKey = makeCollationKey(musicSettings)
+    override val sortName = (rawSortName ?: rawName)?.let { SortName(it, musicSettings) }
     override fun resolveName(context: Context) = rawName ?: context.getString(R.string.def_genre)
 
     override val albums: List<Album>
@@ -532,31 +524,3 @@ fun MessageDigest.update(n: Int?) {
         update(0)
     }
 }
-
-/** Cached collator instance re-used with [makeCollationKey]. */
-private val COLLATOR: Collator = Collator.getInstance().apply { strength = Collator.PRIMARY }
-
-/**
- * Provided implementation to create a [CollationKey] in the way described by [Music.collationKey].
- * This should be used in all overrides of all [CollationKey].
- *
- * @param musicSettings [MusicSettings] required for user parsing configuration.
- * @return A [CollationKey] that follows the specification described by [Music.collationKey].
- */
-private fun Music.makeCollationKey(musicSettings: MusicSettings): CollationKey? {
-    var sortName = (rawSortName ?: rawName) ?: return null
-
-    if (musicSettings.automaticSortNames) {
-        sortName =
-            sortName.run {
-                when {
-                    length > 5 && startsWith("the ", ignoreCase = true) -> substring(4)
-                    length > 4 && startsWith("an ", ignoreCase = true) -> substring(3)
-                    length > 3 && startsWith("a ", ignoreCase = true) -> substring(2)
-                    else -> this
-                }
-            }
-    }
-
-    return COLLATOR.getCollationKey(sortName)
-}

app/src/main/java/org/oxycblt/auxio/playback/queue/QueueAdapter.kt

@@ -173,7 +173,6 @@ class QueueSongViewHolder private constructor(private val binding: ItemQueueSong
         fun from(parent: View) =
             QueueSongViewHolder(ItemQueueSongBinding.inflate(parent.context.inflater))
 
-        // TODO: This is not good enough, I need to compare item indices as well.
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK = SongViewHolder.DIFF_CALLBACK
     }

app/src/main/java/org/oxycblt/auxio/playback/queue/QueueDragCallback.kt

@@ -33,8 +33,6 @@ import org.oxycblt.auxio.util.logD
  * such as an animation when lifting items.
  *
  * @author Alexander Capehart (OxygenCobalt)
- *
- * TODO: Why is item movement so expensive???
  */
 class QueueDragCallback(private val playbackModel: QueueViewModel) : ItemTouchHelper.Callback() {
     private var shouldLift = true