Currently playing music track displayed under Options-Sound (#5357)

android/assets/jsons/translations/template.properties

@@ -474,6 +474,7 @@ Turns between autosaves =
 Sound effects volume = 
 Music volume = 
 Pause between tracks = 
+Currently playing: [title] = 
 Download music = 
 Downloading... = 
 Could not download music! = 

core/src/com/unciv/ui/audio/MusicController.kt

@@ -78,13 +78,39 @@ class MusicController {
     /** Keeps paths of recently played track to reduce repetition */
     private val musicHistory = ArrayDeque<String>(musicHistorySize)
 
+    /** One potential listener gets notified when track changes */
+    private var onTrackChangeListener: ((String)->Unit)? = null
+
     //endregion
     //region Pure functions
 
     /** @return the path of the playing track or null if none playing */
-    fun currentlyPlaying() = if (state != ControllerState.Playing && state != ControllerState.PlaySingle) null
+    private fun currentlyPlaying(): String = if (state != ControllerState.Playing && state != ControllerState.PlaySingle) ""
         else musicHistory.peekLast()
 
+    /** Registers a callback that will be called with the new track name every time it changes.
+     *  The track name will be prettified ("Modname: Track" instead of "mods/Modname/music/Track.ogg").
+     *
+     *  Will be called on a background thread, so please decouple UI access on the receiving side.
+     */
+    fun onChange(listener: ((String)->Unit)?) {
+        onTrackChangeListener = listener
+        fireOnChange()
+    }
+    private fun fireOnChange() {
+        val fileName = currentlyPlaying()
+        if (fileName.isEmpty()) {
+            onTrackChangeListener?.invoke(fileName)
+            return
+        }
+        val fileNameParts = fileName.split('/')
+        val modName = if (fileNameParts.size > 1 && fileNameParts[0] == "mods") fileNameParts[1] else ""
+        var trackName = fileNameParts[if (fileNameParts.size > 3 && fileNameParts[2] == "music") 3 else 1]
+        for (extension in fileExtensions)
+            trackName = trackName.removeSuffix(".$extension")
+        onTrackChangeListener?.invoke(modName + (if (modName.isEmpty()) "" else ": ") + trackName)
+    }
+
     /**
      * Determines whether any music tracks are available for the options menu
      */
@@ -112,12 +138,15 @@ class MusicController {
                         // no music to play - begin silence or shut down
                         ticksOfSilence = 0
                         state = if (state == ControllerState.PlaySingle) ControllerState.Shutdown else ControllerState.Silence
+                        fireOnChange()
                     } else if (next!!.state.canPlay) {
                         // Next track - if top slot empty and a next exists, move it to top and start
                         current = next
                         next = null
                         if (!current!!.play())
                             state = ControllerState.Shutdown
+                        else
+                            fireOnChange()
                     } // else wait for the thread of next.load() to finish
                 } else if (!current!!.isPlaying()) {
                     // normal end of track
@@ -133,10 +162,13 @@ class MusicController {
                     ticksOfSilence = 0
                     chooseTrack()
                 }
-            ControllerState.Shutdown, ControllerState.Idle -> {
+            ControllerState.Shutdown -> {
+                // Fade out first, when all queue entries are idle set up for real shutdown
+                if (current?.shutdownTick() != false && next?.shutdownTick() != false)
                     state = ControllerState.Idle
-                shutdown()
             }
+            ControllerState.Idle ->
+                shutdown()  // stops timer so this will not repeat
             ControllerState.Pause ->
                 current?.timerTick()
         }
@@ -311,8 +343,10 @@ class MusicController {
     }
 
     /** Forceful shutdown of music playback and timers - see [gracefulShutdown] */
-    fun shutdown() {
+    private fun shutdown() {
         state = ControllerState.Idle
+        fireOnChange()
+        onTrackChangeListener = null
         if (musicTimer != null) {
             musicTimer!!.cancel()
             musicTimer = null

core/src/com/unciv/ui/audio/MusicTrackController.kt

@@ -99,7 +99,9 @@ class MusicTrackController(private var volume: Float) {
     }
     private fun fadeOutStep() {
         // fade-out: linearly ramp fadeVolume to 0.0, then act according to Status (Playing->Silence/Pause/Shutdown)
+        // This needs to guard against the music backend breaking mid-fade away during game shutdown
         fadeVolume -= fadeStep
+        try {
             if (fadeVolume >= 0.001f && music != null && music!!.isPlaying) {
                 music!!.volume = volume * fadeVolume
                 return
@@ -107,6 +109,7 @@ class MusicTrackController(private var volume: Float) {
             fadeVolume = 0f
             music!!.volume = 0f
             music!!.pause()
+        } catch (_: Throwable) {}
         state = State.Idle
     }
 
@@ -121,6 +124,19 @@ class MusicTrackController(private var volume: Float) {
         state = fade
     }
 
+    /** Graceful shutdown tick event - fade out then report Idle
+     *  @return `true` shutdown can proceed, `false` still fading out
+     */
+    fun shutdownTick(): Boolean {
+        if (!state.canPlay) state = State.Idle
+        if (state == State.Idle) return true
+        if (state != State.FadeOut) {
+            state = State.FadeOut
+            fadeStep = MusicController.defaultFadingStep
+        }
+        return timerTick() == State.Idle
+    }
+
     /** @return [Music.isPlaying] (Gdx music stream is playing) unless [state] says it won't make sense */
     fun isPlaying() = state.canPlay && music?.isPlaying == true
 

core/src/com/unciv/ui/worldscreen/mainmenu/OptionsPopup.kt

@@ -84,6 +84,7 @@ class OptionsPopup(val previousScreen: CameraStageBaseScreen) : Popup(previousSc
         }
 
         addCloseButton {
+            previousScreen.game.musicController.onChange(null)
             previousScreen.game.limitOrientationsHelper?.allowPortrait(settings.allowAndroidPortrait)
             if (previousScreen is WorldScreen)
                 previousScreen.enableNextTurnButtonAfterOptions()
@@ -210,6 +211,7 @@ class OptionsPopup(val previousScreen: CameraStageBaseScreen) : Popup(previousSc
         if (previousScreen.game.musicController.isMusicAvailable()) {
             addMusicVolumeSlider()
             addMusicPauseSlider()
+            addMusicCurrentlyPlaying()
         } else {
             addDownloadMusic()
         }
@@ -456,6 +458,17 @@ class OptionsPopup(val previousScreen: CameraStageBaseScreen) : Popup(previousSc
         add(pauseLengthSlider).pad(5f).row()
     }
 
+    private fun Table.addMusicCurrentlyPlaying() {
+        val label = WrappableLabel("", this.width - 10f, Color(-0x2f5001), 16)
+        label.wrap = true
+        add(label).padTop(20f).colspan(2).fillX().row()
+        previousScreen.game.musicController.onChange {
+            Gdx.app.postRunnable {
+                label.setText("Currently playing: [$it]".tr())
+            }
+        }
+    }
+
     private fun Table.addDownloadMusic() {
         val downloadMusicButton = "Download music".toTextButton()
         add(downloadMusicButton).colspan(2).row()