music: add picker dialog

Add a dialog for picking a genre from several choices.

This basically completes multi-genre support in Auxio, save more
internal reworks.

Note that it is extremely likely that the "Play from genre" setting
will be removed soon. This feature has made me realize that such does
not many any real sense, as genres are more semantically similar to
playlists than artists or albums. This implementation only exists to
make multi-artist support an easy plug-and-play operation.

Resolves #201

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

@@ -29,16 +29,20 @@ import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import androidx.recyclerview.widget.LinearSmoothScroller
 import com.google.android.material.transition.MaterialSharedAxis
+import org.oxycblt.auxio.MainFragmentDirections
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentDetailBinding
 import org.oxycblt.auxio.detail.recycler.AlbumDetailAdapter
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.ui.Sort
+import org.oxycblt.auxio.music.Sort
+import org.oxycblt.auxio.music.picker.PickerMode
 import org.oxycblt.auxio.settings.Settings
+import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.fragment.MenuFragment
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.util.canScroll
@@ -125,11 +129,19 @@ class AlbumDetailFragment :
 
     override fun onItemClick(item: Item) {
         check(item is Song) { "Unexpected datatype: ${item::class.simpleName}" }
-        val playbackMode = settings.detailPlaybackMode
+        when (settings.detailPlaybackMode) {
-        if (playbackMode != null) {
+            null, MusicMode.ALBUMS -> playbackModel.playFromAlbum(item)
-            playbackModel.play(item, playbackMode)
+            MusicMode.SONGS -> playbackModel.play(item)
-        } else {
+            MusicMode.ARTISTS -> playbackModel.playFromArtist(item)
-            playbackModel.playFromAlbum(item)
+            MusicMode.GENRES -> if (item.genres.size > 1) {
+                navModel.mainNavigateTo(
+                    MainNavigationAction.Directions(
+                        MainFragmentDirections.showGenrePickerDialog(item.uid, PickerMode.PLAY)
+                    )
+                )
+            } else {
+                playbackModel.playFromGenre(item, item.genres[0])
+            }
         }
     }
 

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

@@ -26,6 +26,7 @@ import androidx.fragment.app.activityViewModels
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import com.google.android.material.transition.MaterialSharedAxis
+import org.oxycblt.auxio.MainFragmentDirections
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentDetailBinding
 import org.oxycblt.auxio.detail.recycler.ArtistDetailAdapter
@@ -33,10 +34,13 @@ import org.oxycblt.auxio.detail.recycler.DetailAdapter
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.ui.Sort
+import org.oxycblt.auxio.music.Sort
+import org.oxycblt.auxio.music.picker.PickerMode
 import org.oxycblt.auxio.settings.Settings
+import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.fragment.MenuFragment
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.util.collect
@@ -117,11 +121,19 @@ class ArtistDetailFragment :
     override fun onItemClick(item: Item) {
         when (item) {
             is Song -> {
-                val playbackMode = settings.detailPlaybackMode
+                when (settings.detailPlaybackMode) {
-                if (playbackMode != null) {
+                    null, MusicMode.ARTISTS -> playbackModel.playFromArtist(item)
-                    playbackModel.play(item, playbackMode)
+                    MusicMode.SONGS -> playbackModel.play(item)
-                } else {
+                    MusicMode.ALBUMS -> playbackModel.playFromAlbum(item)
-                    playbackModel.playFromArtist(item)
+                    MusicMode.GENRES -> if (item.genres.size > 1) {
+                        navModel.mainNavigateTo(
+                            MainNavigationAction.Directions(
+                                MainFragmentDirections.showGenrePickerDialog(item.uid, PickerMode.PLAY)
+                            )
+                        )
+                    } else {
+                        playbackModel.playFromGenre(item, item.genres[0])
+                    }
                 }
             }
             is Album -> navModel.exploreNavigateTo(item)

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

@@ -38,7 +38,7 @@ import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.ReleaseType
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.ui.Sort
+import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.ui.recycler.Header
 import org.oxycblt.auxio.ui.recycler.Item

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

@@ -26,6 +26,7 @@ import androidx.fragment.app.activityViewModels
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import com.google.android.material.transition.MaterialSharedAxis
+import org.oxycblt.auxio.MainFragmentDirections
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentDetailBinding
 import org.oxycblt.auxio.detail.recycler.DetailAdapter
@@ -34,10 +35,13 @@ 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.MusicParent
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.ui.Sort
+import org.oxycblt.auxio.music.Sort
+import org.oxycblt.auxio.music.picker.PickerMode
 import org.oxycblt.auxio.settings.Settings
+import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.fragment.MenuFragment
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.util.collect
@@ -117,11 +121,20 @@ class GenreDetailFragment :
 
     override fun onItemClick(item: Item) {
         check(item is Song) { "Unexpected datatype: ${item::class.simpleName}" }
-        val playbackMode = settings.detailPlaybackMode
+        when (settings.detailPlaybackMode) {
-        if (playbackMode != null) {
+            null -> playbackModel.playFromGenre(item, unlikelyToBeNull(detailModel.currentGenre.value))
-            playbackModel.play(item, playbackMode)
+            MusicMode.SONGS -> playbackModel.play(item)
-        } else {
+            MusicMode.ALBUMS -> playbackModel.playFromAlbum(item)
-            playbackModel.playFromGenre(item, unlikelyToBeNull(detailModel.currentGenre.value))
+            MusicMode.ARTISTS -> playbackModel.playFromArtist(item)
+            MusicMode.GENRES -> if (item.genres.size > 1) {
+                navModel.mainNavigateTo(
+                    MainNavigationAction.Directions(
+                        MainFragmentDirections.showGenrePickerDialog(item.uid, PickerMode.PLAY)
+                    )
+                )
+            } else {
+                playbackModel.playFromGenre(item, item.genres[0])
+            }
         }
     }
 

app/src/main/java/org/oxycblt/auxio/home/AdaptiveTabStrategy.kt

@@ -21,7 +21,7 @@ import android.content.Context
 import com.google.android.material.tabs.TabLayout
 import com.google.android.material.tabs.TabLayoutMediator
 import org.oxycblt.auxio.R
-import org.oxycblt.auxio.music.ui.MusicMode
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.util.logD
 
 /**

app/src/main/java/org/oxycblt/auxio/home/HomeFragment.kt

@@ -48,11 +48,11 @@ 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.MusicViewModel
 import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.music.system.Indexer
-import org.oxycblt.auxio.music.ui.MusicMode
-import org.oxycblt.auxio.music.ui.Sort
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.NavigationViewModel

app/src/main/java/org/oxycblt/auxio/home/HomeViewModel.kt

@@ -26,10 +26,10 @@ import org.oxycblt.auxio.home.tabs.Tab
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Genre
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.ui.MusicMode
+import org.oxycblt.auxio.music.Sort
-import org.oxycblt.auxio.music.ui.Sort
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.util.application
 import org.oxycblt.auxio.util.logD

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

@@ -24,11 +24,11 @@ import android.view.ViewGroup
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.music.Album
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
+import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.music.formatDurationMs
 import org.oxycblt.auxio.music.secsToMs
-import org.oxycblt.auxio.music.ui.MusicMode
-import org.oxycblt.auxio.music.ui.Sort
 import org.oxycblt.auxio.ui.recycler.AlbumViewHolder
 import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item

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

@@ -23,10 +23,10 @@ import android.view.ViewGroup
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.music.Artist
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
+import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.music.formatDurationMs
-import org.oxycblt.auxio.music.ui.MusicMode
-import org.oxycblt.auxio.music.ui.Sort
 import org.oxycblt.auxio.ui.recycler.ArtistViewHolder
 import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item

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

@@ -23,10 +23,10 @@ import android.view.ViewGroup
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.music.Genre
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
+import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.music.formatDurationMs
-import org.oxycblt.auxio.music.ui.MusicMode
-import org.oxycblt.auxio.music.ui.Sort
 import org.oxycblt.auxio.ui.recycler.GenreViewHolder
 import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item

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

@@ -21,15 +21,18 @@ import android.os.Bundle
 import android.text.format.DateUtils
 import android.view.View
 import android.view.ViewGroup
+import org.oxycblt.auxio.MainFragmentDirections
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.music.formatDurationMs
+import org.oxycblt.auxio.music.picker.PickerMode
 import org.oxycblt.auxio.music.secsToMs
-import org.oxycblt.auxio.music.ui.MusicMode
-import org.oxycblt.auxio.music.ui.Sort
 import org.oxycblt.auxio.settings.Settings
+import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.ui.recycler.MenuItemListener
@@ -109,7 +112,20 @@ class SongListFragment : HomeListFragment<Song>() {
 
     override fun onItemClick(item: Item) {
         check(item is Song) { "Unexpected datatype: ${item::class.java}" }
-        playbackModel.play(item, settings.libPlaybackMode)
+        when (settings.libPlaybackMode) {
+            MusicMode.SONGS -> playbackModel.play(item)
+            MusicMode.ALBUMS -> playbackModel.playFromAlbum(item)
+            MusicMode.ARTISTS -> playbackModel.playFromArtist(item)
+            MusicMode.GENRES -> if (item.genres.size > 1) {
+                navModel.mainNavigateTo(
+                    MainNavigationAction.Directions(
+                        MainFragmentDirections.showGenrePickerDialog(item.uid, PickerMode.PLAY)
+                    )
+                )
+            } else {
+                playbackModel.playFromGenre(item, item.genres[0])
+            }
+        }
     }
 
     override fun onOpenMenu(item: Item, anchor: View) {

app/src/main/java/org/oxycblt/auxio/home/tabs/Tab.kt

@@ -21,7 +21,7 @@ import org.oxycblt.auxio.home.tabs.Tab.Companion.fromSequence
 import org.oxycblt.auxio.home.tabs.Tab.Companion.toSequence
 import org.oxycblt.auxio.home.tabs.Tab.Invisible
 import org.oxycblt.auxio.home.tabs.Tab.Visible
-import org.oxycblt.auxio.music.ui.MusicMode
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.util.logE
 
 /**

app/src/main/java/org/oxycblt/auxio/home/tabs/TabAdapter.kt

@@ -24,7 +24,7 @@ import android.view.ViewGroup
 import androidx.recyclerview.widget.RecyclerView
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.ItemTabBinding
-import org.oxycblt.auxio.music.ui.MusicMode
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.ui.recycler.DialogViewHolder
 import org.oxycblt.auxio.util.inflater
 

app/src/main/java/org/oxycblt/auxio/home/tabs/TabCustomizeDialog.kt

@@ -25,7 +25,7 @@ import androidx.recyclerview.widget.RecyclerView
 import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.DialogTabsBinding
-import org.oxycblt.auxio.music.ui.MusicMode
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.ui.fragment.ViewBindingDialogFragment
 import org.oxycblt.auxio.util.context

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

@@ -34,7 +34,7 @@ import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Genre
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.ui.Sort
+import org.oxycblt.auxio.music.Sort
 import kotlin.math.min
 
 /** A basic keyer for music data. */

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

@@ -26,8 +26,6 @@ import kotlinx.parcelize.Parcelize
 import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.music.Date.Companion.from
-import org.oxycblt.auxio.music.ui.MusicMode
-import org.oxycblt.auxio.music.ui.Sort
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.util.inRangeOrNull
 import org.oxycblt.auxio.util.nonZeroOrNull
@@ -105,43 +103,34 @@ sealed class Music : Item {
      */
     @Parcelize
     class UID private constructor(
-        private val isMusicBrainz: Boolean,
+        private val format: Format,
         private val mode: MusicMode,
         private val uuid: UUID
     ) : Parcelable {
         // Cache the hashCode for speed
-        @IgnoredOnParcel private val hashCode: Int
+        @IgnoredOnParcel private var hashCode = format.hashCode()
 
         init {
-            var result = isMusicBrainz.hashCode()
+            hashCode = 31 * hashCode + mode.hashCode()
-            result = 31 * result + mode.hashCode()
+            hashCode = 31 * hashCode + uuid.hashCode()
-            result = 31 * result + uuid.hashCode()
-            hashCode = result
         }
 
         override fun hashCode() = hashCode
 
         override fun equals(other: Any?) = other is UID &&
-            isMusicBrainz == other.isMusicBrainz &&
+            format == other.format &&
             mode == other.mode && uuid == other.uuid
 
-        override fun toString(): String {
+        // UID string format is roughly:
-            // Format comes first, delimited by a ":".
+        // format_namespace:music_mode_int-uuid
-            val format = if (isMusicBrainz) {
+        override fun toString() = "${format.namespace}:${mode.intCode.toString(16)}-$uuid"
-                FORMAT_MUSICBRAINZ
-            } else {
-                FORMAT_AUXIO
-            }
 
-            // Instead of making new string values for the mode, be lazy and just append it's
+        private enum class Format(val namespace: String) {
-            // intCode in front of the UUID.
+            AUXIO("org.oxycblt.auxio"),
-            return "$format:${mode.intCode.toString(16)}-$uuid"
+            MUSICBRAINZ("org.musicbrainz")
         }
 
         companion object {
-            private const val FORMAT_AUXIO = "org.oxycblt.auxio"
-            private const val FORMAT_MUSICBRAINZ = "org.musicbrainz"
-
             /** Parse a [UID] from the string [uid]. Returns null if not valid. */
             fun fromString(uid: String): UID? {
                 val split = uid.split(':', limit = 2)
@@ -149,9 +138,9 @@ sealed class Music : Item {
                     return null
                 }
 
-                val isMusicBrainz = when (split[0]) {
+                val format = when (split[0]) {
-                    FORMAT_MUSICBRAINZ -> true
+                    Format.AUXIO.namespace -> Format.AUXIO
-                    FORMAT_AUXIO -> false
+                    Format.MUSICBRAINZ.namespace -> Format.MUSICBRAINZ
                     else -> return null
                 }
 
@@ -163,7 +152,7 @@ sealed class Music : Item {
                 val mode = MusicMode.fromInt(ids[0].toIntOrNull(16) ?: return null) ?: return null
                 val uuid = UUID.fromString(ids[1])
 
-                return UID(isMusicBrainz, mode, uuid)
+                return UID(format, mode, uuid)
             }
 
             /**
@@ -178,7 +167,7 @@ sealed class Music : Item {
                 val digest = MessageDigest.getInstance("MD5")
                 updates(digest)
                 val uuid = digest.digest().toUuid()
-                return UID(false, mode, uuid)
+                return UID(Format.AUXIO, mode, uuid)
             }
         }
     }

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

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.music.ui
+package org.oxycblt.auxio.music
 
 import org.oxycblt.auxio.IntegerTable
 

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

@@ -26,7 +26,6 @@ import android.provider.MediaStore
 import android.text.format.DateUtils
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.util.logD
-import java.util.UUID
 
 /** Shortcut for making a [ContentResolver] query with less superfluous arguments. */
 fun ContentResolver.queryCursor(

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

@@ -15,18 +15,12 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.music.ui
+package org.oxycblt.auxio.music
 
 import androidx.annotation.IdRes
 import org.oxycblt.auxio.IntegerTable
 import org.oxycblt.auxio.R
-import org.oxycblt.auxio.music.Album
+import org.oxycblt.auxio.music.Sort.Mode
-import org.oxycblt.auxio.music.Artist
-import org.oxycblt.auxio.music.Date
-import org.oxycblt.auxio.music.Genre
-import org.oxycblt.auxio.music.Music
-import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.ui.Sort.Mode
 
 /**
  * Represents the sort modes used in Auxio.

app/src/main/java/org/oxycblt/auxio/music/dirs/MusicDirAdapter.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.music.settings
+package org.oxycblt.auxio.music.dirs
 
 import android.view.View
 import android.view.ViewGroup

app/src/main/java/org/oxycblt/auxio/music/dirs/MusicDirs.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.music.settings
+package org.oxycblt.auxio.music.dirs
 
 import org.oxycblt.auxio.music.Directory
 

app/src/main/java/org/oxycblt/auxio/music/dirs/MusicDirsDialog.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.music.settings
+package org.oxycblt.auxio.music.dirs
 
 import android.net.Uri
 import android.os.Bundle

app/src/main/java/org/oxycblt/auxio/music/picker/GenreChoiceAdapter.kt

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2022 Auxio Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * 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.picker
+
+import android.view.View
+import android.view.ViewGroup
+import androidx.recyclerview.widget.RecyclerView
+import org.oxycblt.auxio.databinding.ItemPickerChoiceBinding
+import org.oxycblt.auxio.music.Genre
+import org.oxycblt.auxio.ui.recycler.DialogViewHolder
+import org.oxycblt.auxio.ui.recycler.ItemClickListener
+import org.oxycblt.auxio.util.context
+import org.oxycblt.auxio.util.inflater
+
+/**
+ * The adapter that displays a list of genre choices in the picker UI.
+ */
+class GenreChoiceAdapter(private val listener: ItemClickListener) : RecyclerView.Adapter<GenreChoiceViewHolder>() {
+    private var genres = listOf<Genre>()
+
+    override fun getItemCount() = genres.size
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
+        GenreChoiceViewHolder.new(parent)
+
+    override fun onBindViewHolder(holder: GenreChoiceViewHolder, position: Int) =
+        holder.bind(genres[position], listener)
+
+    fun submitList(newGenres: List<Genre>) {
+        if (newGenres != genres) {
+            genres = newGenres
+
+            @Suppress("NotifyDataSetChanged")
+            notifyDataSetChanged()
+        }
+    }
+}
+
+/**
+ * The ViewHolder that displays a genre choice. Smaller than other parent items due to dialog
+ * constraints.
+ */
+class GenreChoiceViewHolder(private val binding: ItemPickerChoiceBinding) : DialogViewHolder(binding.root) {
+    fun bind(genre: Genre, listener: ItemClickListener) {
+        binding.pickerImage.bind(genre)
+        binding.pickerName.text = genre.resolveName(binding.context)
+        binding.root.setOnClickListener {
+            listener.onItemClick(genre)
+        }
+    }
+
+    companion object {
+        fun new(parent: View) =
+            GenreChoiceViewHolder(ItemPickerChoiceBinding.inflate(parent.context.inflater))
+    }
+}

app/src/main/java/org/oxycblt/auxio/music/picker/GenrePickerDialog.kt

@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2022 Auxio Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * 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.picker
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import androidx.appcompat.app.AlertDialog
+import androidx.fragment.app.activityViewModels
+import androidx.fragment.app.viewModels
+import androidx.navigation.fragment.findNavController
+import androidx.navigation.fragment.navArgs
+import org.oxycblt.auxio.R
+import org.oxycblt.auxio.databinding.DialogMusicPickerBinding
+import org.oxycblt.auxio.music.Genre
+import org.oxycblt.auxio.playback.PlaybackViewModel
+import org.oxycblt.auxio.ui.NavigationViewModel
+import org.oxycblt.auxio.ui.fragment.ViewBindingDialogFragment
+import org.oxycblt.auxio.ui.recycler.Item
+import org.oxycblt.auxio.ui.recycler.ItemClickListener
+import org.oxycblt.auxio.util.androidActivityViewModels
+import org.oxycblt.auxio.util.collectImmediately
+import org.oxycblt.auxio.util.unlikelyToBeNull
+
+/**
+ * A dialog that shows several genre options if the result of an genre-reliant operation is
+ * ambiguous.
+ * @author OxygenCobalt
+ */
+class GenrePickerDialog : ViewBindingDialogFragment<DialogMusicPickerBinding>(), ItemClickListener {
+    private val pickerModel: PickerViewModel by viewModels()
+    private val playbackModel: PlaybackViewModel by androidActivityViewModels()
+    private val navModel: NavigationViewModel by activityViewModels()
+
+    private val args: GenrePickerDialogArgs by navArgs()
+    private val adapter = GenreChoiceAdapter(this)
+
+    override fun onCreateBinding(inflater: LayoutInflater) =
+        DialogMusicPickerBinding.inflate(inflater)
+
+    override fun onConfigDialog(builder: AlertDialog.Builder) {
+        builder
+            .setTitle(
+                when (args.pickerMode) {
+                    PickerMode.GO -> R.string.lbl_go_genre
+                    PickerMode.PLAY -> R.string.lbl_play_genre
+                }
+            )
+            .setNegativeButton(R.string.lbl_cancel, null)
+    }
+
+    override fun onBindingCreated(binding: DialogMusicPickerBinding, savedInstanceState: Bundle?) {
+        pickerModel.setSongUid(args.songUid)
+
+        binding.pickerRecycler.adapter = adapter
+
+        collectImmediately(pickerModel.currentSong) { song ->
+            if (song != null) {
+                adapter.submitList(song.genres)
+            } else {
+                findNavController().navigateUp()
+            }
+        }
+    }
+
+    override fun onDestroyBinding(binding: DialogMusicPickerBinding) {
+        binding.pickerRecycler.adapter = null
+    }
+
+    override fun onItemClick(item: Item) {
+        check(item is Genre) { "Unexpected datatype: ${item::class.simpleName}" }
+        findNavController().navigateUp()
+        when (args.pickerMode) {
+            PickerMode.GO -> navModel.exploreNavigateTo(item)
+            PickerMode.PLAY -> {
+                val song = unlikelyToBeNull(pickerModel.currentSong.value)
+                playbackModel.playFromGenre(song, item)
+            }
+        }
+    }
+}

app/src/main/java/org/oxycblt/auxio/music/picker/PickerMode.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2022 Auxio Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * 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.picker
+
+/**
+ * Represents the actions available to the picker UI.
+ */
+enum class PickerMode {
+    PLAY,
+    GO
+}

app/src/main/java/org/oxycblt/auxio/music/picker/PickerViewModel.kt

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2022 Auxio Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * 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.picker
+
+import androidx.lifecycle.ViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import org.oxycblt.auxio.music.Music
+import org.oxycblt.auxio.music.MusicStore
+import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.util.unlikelyToBeNull
+
+/**
+ * A small ViewModel holding and updating the current song being shown in the picker UI.
+ * @author OxygenCobalt
+ */
+class PickerViewModel : ViewModel(), MusicStore.Callback {
+    private val musicStore = MusicStore.getInstance()
+
+    private val _currentSong = MutableStateFlow<Song?>(null)
+    val currentSong: StateFlow<Song?> get() = _currentSong
+
+    fun setSongUid(uid: Music.UID) {
+        if (_currentSong.value?.uid == uid) return
+        val library = unlikelyToBeNull(musicStore.library)
+        _currentSong.value = requireNotNull(library.find(uid)) { "Invalid song id provided" }
+    }
+
+    override fun onLibraryChanged(library: MusicStore.Library?) {
+        if (library != null) {
+            val song = _currentSong.value
+            if (song != null) {
+                _currentSong.value = library.sanitize(song)
+            }
+        }
+    }
+}

app/src/main/java/org/oxycblt/auxio/music/separators/SeparatorsDialog.kt

@@ -15,14 +15,13 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.music.settings
+package org.oxycblt.auxio.music.separators
 
 import android.os.Bundle
 import android.view.LayoutInflater
 import androidx.appcompat.app.AlertDialog
 import androidx.core.view.children
 import com.google.android.material.checkbox.MaterialCheckBox
-import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.DialogSeparatorsBinding
 import org.oxycblt.auxio.settings.Settings

app/src/main/java/org/oxycblt/auxio/music/system/Indexer.kt

@@ -32,12 +32,12 @@ import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Genre
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.music.extractor.Api21MediaStoreLayer
 import org.oxycblt.auxio.music.extractor.Api29MediaStoreLayer
 import org.oxycblt.auxio.music.extractor.Api30MediaStoreLayer
 import org.oxycblt.auxio.music.extractor.CacheLayer
 import org.oxycblt.auxio.music.extractor.MetadataLayer
-import org.oxycblt.auxio.music.ui.Sort
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.logE
 import org.oxycblt.auxio.util.logW

app/src/main/java/org/oxycblt/auxio/playback/PlaybackViewModel.kt

@@ -32,7 +32,6 @@ import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.music.dsToMs
 import org.oxycblt.auxio.music.msToDs
-import org.oxycblt.auxio.music.ui.MusicMode
 import org.oxycblt.auxio.playback.state.InternalPlayer
 import org.oxycblt.auxio.playback.state.PlaybackStateDatabase
 import org.oxycblt.auxio.playback.state.PlaybackStateManager
@@ -92,19 +91,9 @@ class PlaybackViewModel(application: Application) :
 
     // --- PLAYING FUNCTIONS ---
 
-    /** Play a [song] with the [mode] specified, */
+    /** Play a [song] from all songs. */
-    fun play(song: Song, mode: MusicMode) {
+    fun play(song: Song) {
-        // TODO: Remove this function when selection is implemented
+        playbackManager.play(song, null, settings)
-
-        val parent =
-            when (mode) {
-                MusicMode.GENRES -> song.album
-                MusicMode.ARTISTS -> song.album.artist
-                MusicMode.ALBUMS -> song.genres.maxBy { it.songs.size }
-                MusicMode.SONGS -> null
-            }
-
-        playbackManager.play(song, parent, settings)
     }
 
     /** Play a song from it's album. */

app/src/main/java/org/oxycblt/auxio/playback/replaygain/PreAmpCustomizeDialog.kt

@@ -21,7 +21,6 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import android.widget.TextView
 import androidx.appcompat.app.AlertDialog
-import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.DialogPreAmpBinding
 import org.oxycblt.auxio.settings.Settings

app/src/main/java/org/oxycblt/auxio/search/SearchFragment.kt

@@ -29,16 +29,19 @@ import androidx.core.widget.addTextChangedListener
 import androidx.fragment.app.Fragment
 import androidx.navigation.fragment.findNavController
 import com.google.android.material.transition.MaterialSharedAxis
+import org.oxycblt.auxio.MainFragmentDirections
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentSearchBinding
 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.MusicParent
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.ui.MusicMode
+import org.oxycblt.auxio.music.picker.PickerMode
 import org.oxycblt.auxio.settings.Settings
+import org.oxycblt.auxio.ui.MainNavigationAction
 import org.oxycblt.auxio.ui.fragment.MenuFragment
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.ui.recycler.MenuItemListener
@@ -147,7 +150,20 @@ class SearchFragment :
 
     override fun onItemClick(item: Item) {
         when (item) {
-            is Song -> playbackModel.play(item, settings.libPlaybackMode)
+            is Song -> when (settings.libPlaybackMode) {
+                MusicMode.SONGS -> playbackModel.play(item)
+                MusicMode.ALBUMS -> playbackModel.playFromAlbum(item)
+                MusicMode.ARTISTS -> playbackModel.playFromArtist(item)
+                MusicMode.GENRES -> if (item.genres.size > 1) {
+                    navModel.mainNavigateTo(
+                        MainNavigationAction.Directions(
+                            MainFragmentDirections.showGenrePickerDialog(item.uid, PickerMode.PLAY)
+                        )
+                    )
+                } else {
+                    playbackModel.playFromGenre(item, item.genres[0])
+                }
+            }
             is MusicParent -> navModel.exploreNavigateTo(item)
         }
     }

app/src/main/java/org/oxycblt/auxio/search/SearchViewModel.kt

@@ -33,10 +33,10 @@ 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.MusicStore
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.music.ui.MusicMode
+import org.oxycblt.auxio.music.Sort
-import org.oxycblt.auxio.music.ui.Sort
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.ui.recycler.Header
 import org.oxycblt.auxio.ui.recycler.Item

app/src/main/java/org/oxycblt/auxio/settings/Settings.kt

@@ -28,9 +28,9 @@ import org.oxycblt.auxio.IntegerTable
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.home.tabs.Tab
 import org.oxycblt.auxio.music.Directory
-import org.oxycblt.auxio.music.settings.MusicDirs
+import org.oxycblt.auxio.music.MusicMode
-import org.oxycblt.auxio.music.ui.MusicMode
+import org.oxycblt.auxio.music.Sort
-import org.oxycblt.auxio.music.ui.Sort
+import org.oxycblt.auxio.music.dirs.MusicDirs
 import org.oxycblt.auxio.playback.BarAction
 import org.oxycblt.auxio.playback.replaygain.ReplayGainMode
 import org.oxycblt.auxio.playback.replaygain.ReplayGainPreAmp

app/src/main/res/layout/dialog_music_picker.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<org.oxycblt.auxio.ui.recycler.DialogRecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/picker_recycler"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
+    tools:listitem="@layout/item_picker_choice" />

app/src/main/res/layout/item_picker_choice.xml

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:background="?attr/selectableItemBackground"
+    android:paddingStart="@dimen/spacing_mid_large"
+    android:paddingTop="@dimen/spacing_medium"
+    android:paddingEnd="@dimen/spacing_mid_large"
+    android:paddingBottom="@dimen/spacing_medium">
+
+    <org.oxycblt.auxio.image.ImageGroup
+        android:id="@+id/picker_image"
+        style="@style/Widget.Auxio.Image.Small"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        tools:staticIcon="@drawable/ic_song_24" />
+
+    <TextView
+        android:id="@+id/picker_name"
+        style="@style/Widget.Auxio.TextView.Item.Primary"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_marginEnd="@dimen/spacing_mid_medium"
+        android:textColor="@color/sel_accented_primary"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toEndOf="@+id/picker_image"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintVertical_chainStyle="packed"
+        tools:text="Artist" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/navigation/nav_main.xml

@@ -17,8 +17,24 @@
         <action
             android:id="@+id/action_show_details"
             app:destination="@id/song_detail_dialog" />
+        <action
+            android:id="@+id/show_genre_picker_dialog"
+            app:destination="@id/genre_picker_dialog" />
     </fragment>
 
+    <dialog
+        android:id="@+id/genre_picker_dialog"
+        android:name="org.oxycblt.auxio.music.picker.GenrePickerDialog"
+        android:label="genre_picker_dialog"
+        tools:layout="@layout/dialog_music_picker">
+        <argument
+            android:name="songUid"
+            app:argType="org.oxycblt.auxio.music.Music$UID" />
+        <argument
+            android:name="pickerMode"
+            app:argType="org.oxycblt.auxio.music.picker.PickerMode" />
+    </dialog>
+
     <dialog
         android:id="@+id/song_detail_dialog"
         android:name="org.oxycblt.auxio.detail.SongDetailDialog"
@@ -67,12 +83,12 @@
         tools:layout="@layout/dialog_pre_amp" />
     <dialog
         android:id="@+id/music_dirs_dialog"
-        android:name="org.oxycblt.auxio.music.settings.MusicDirsDialog"
+        android:name="org.oxycblt.auxio.music.dirs.MusicDirsDialog"
         android:label="music_dirs_dialog"
         tools:layout="@layout/dialog_music_dirs" />
     <dialog
         android:id="@+id/separators_dialog"
-        android:name="org.oxycblt.auxio.music.settings.SeparatorsDialog"
+        android:name="org.oxycblt.auxio.music.separators.SeparatorsDialog"
         android:label="music_dirs_dialog"
         tools:layout="@layout/dialog_separators" />
 

app/src/main/res/values/strings.xml

@@ -102,8 +102,11 @@
     <string name="lbl_play_next">Play next</string>
     <string name="lbl_queue_add">Add to queue</string>
 
+    <string name="lbl_go_genre">Go to genre</string>
     <string name="lbl_go_artist">Go to artist</string>
     <string name="lbl_go_album">Go to album</string>
+    <string name="lbl_play_genre">Play from genre</string>
+    <string name="lbl_play_artist">Play from artist</string>
     <string name="lbl_song_detail">View properties</string>
 
     <string name="lbl_props">Song properties</string>
@@ -203,8 +206,8 @@
     <string name="set_playback_mode_none">Play from shown item</string>
     <string name="set_playback_mode_all">Play from all songs</string>
     <string name="set_playback_mode_album">Play from album</string>
-    <string name="set_playback_mode_artist">Play from artist</string>
+    <string name="set_playback_mode_artist">@string/lbl_play_artist</string>
-    <string name="set_playback_mode_genre">Play from genre</string>
+    <string name="set_playback_mode_genre">@string/lbl_play_genre</string>
     <string name="set_keep_shuffle">Remember shuffle</string>
     <string name="set_keep_shuffle_desc">Keep shuffle on when playing a new song</string>
     <string name="set_rewind_prev">Rewind before skipping back</string>