Add metronome count-in before play midi file on desktop & android

composeApp/src/androidMain/kotlin/mg/dot/feufaro/midi/MidiPlayer.kt

@@ -11,6 +11,7 @@ import java.io.RandomAccessFile
 
 actual class FMediaPlayer actual constructor(
     private val filename: String,
+    private val sharedScreenModel: SharedScreenModel,
     private val onFinished: () -> Unit
 ): KoinComponent {
     private data class MidiEvent(
@@ -643,17 +644,68 @@ actual class FMediaPlayer actual constructor(
         }
     }
 
+    private var countInJob: Job? = null
+
+    private fun getCountInBeats(measureStr: String): Int {
+        val firstNumeratorChar = measureStr.substringBefore('/').trim()
+        return firstNumeratorChar.toIntOrNull() ?: 4
+    }
     actual fun play() {
         if (sequence == null) return
-        applyVoiceStates()
+        if(currentTickPos == 0L) {
-        startPlaybackLoop()
+            playCountIn()
-        println("Android MIDI play — tick=$currentTickPos bpm=$targetBpm")
+        } else {
+            applyVoiceStates()
+            startPlaybackLoop()
+            println("Android MIDI play — tick=$currentTickPos bpm=$targetBpm")
+        }
+    }
+
+    private fun playCountIn() {
+        countInJob?.cancel()
+        countInJob = playerScope.launch(Dispatchers.Default) {
+            val bpm = targetBpm
+            val beatDurationMs = (60_000L / bpm).toLong()
+
+            val noteEvent = 42 // 39:Hand clap
+            val velocity = 100
+            val originalMeasure = sharedScreenModel.measureInt.value
+            val nbSilent = sharedScreenModel.silentDurationBefore.value
+
+            val adjustedMeasure = when {
+                originalMeasure == 6 -> 3
+                originalMeasure % 2 != 0 && originalMeasure > 3 -> 3
+                originalMeasure % 2 == 0 && originalMeasure > 4 -> 4
+                else -> originalMeasure
+            }
+            val anacrouseBeats = nbSilent / 4
+            val totalBeats = if (anacrouseBeats > 5) anacrouseBeats else adjustedMeasure + anacrouseBeats
+//            println("Android Décompte total : $totalBeats bips ($adjustedMeasure de préparation + $anacrouseBeats d'anacrouse) à $bpm BPM")
+
+            val noteOnEvent = byteArrayOf(0x99.toByte(), noteEvent.toByte(), velocity.toByte())
+            val noteOffEvent = byteArrayOf(0x89.toByte(), noteEvent.toByte(), 0.toByte())
+
+            for (i in 1..totalBeats) {
+                midiDriver.write(noteOnEvent)
+                delay(100)
+                midiDriver.write(noteOffEvent)
+
+                delay((beatDurationMs - 100).coerceAtLeast(0L))
+            }
+
+            withContext(Dispatchers.Main) {
+                applyVoiceStates()
+                startPlaybackLoop()
+            }
+        }
     }
     actual fun pause() {
+        countInJob?.cancel()
         isRunning = false; isHolding = false
         playJob?.cancel(); allNotesOff()
     }
     actual fun stop() {
+        countInJob?.cancel()
         isRunning = false; isHolding = false
         playJob?.cancel(); navigationJob?.cancel()
         allNotesOff(); currentTickPos = 0L

composeApp/src/commonMain/kotlin/mg/dot/feufaro/midi/MidiPlayer.kt

@@ -4,7 +4,7 @@ import SharedScreenModel
 import mg.dot.feufaro.FileRepository
 import mg.dot.feufaro.viewmodel.MidiMarkers
 
-expect class FMediaPlayer(filename: String, onFinished: () -> Unit) {
+expect class FMediaPlayer(filename: String, sharedScreenModel: SharedScreenModel, onFinished: () -> Unit) {
     fun play()
     fun pause()
     fun stop()

composeApp/src/commonMain/kotlin/mg/dot/feufaro/solfa/Solfa.kt

@@ -1991,12 +1991,41 @@ class Solfa(val sharedScreenModel: SharedScreenModel, private val fileRepository
         T.add(newTemplateItem)
     }
 
+    private fun decodeDuration(duration: String): Int {
+        return when (duration) {
+            "0" -> 0
+            "1" -> 1
+            "2" -> 2
+            "3" -> 3
+            "4" -> 4
+            "6" -> 6
+            "8" -> 8
+            "A" -> 10
+            "B" -> 11
+            "C" -> 12
+            "E" -> 14
+            "G" -> 16
+            "K" -> 20
+            "O" -> 24
+            "S" -> 28
+            "W" -> 32
+            else -> 0
+        }
+    }
     fun loadU(line: String) {
         val measureLong = meta.getOrElse("m") { "4/4" }
         val measure = measureLong.split("/")[0].toIntOrNull() ?: 4
         val uObject = ParseULine(line, measure)
         val parsedULine = uObject.parsed()
         loadT(parsedULine)
+
+        val regex = Regex("""z([^:]):""")
+        val match = regex.find(line)
+        val silentDuration = match?.groupValues?.get(1) ?: "0"
+
+        sharedScreenModel.setMeasureInt(measure)
+        sharedScreenModel.setSilentDurBefr(decodeDuration(silentDuration))
+//        println(silentDuration)
     }
 
     fun loadO(index: Int, line: String) {

composeApp/src/commonMain/kotlin/mg/dot/feufaro/viewmodel/SharedScreenModel.kt

@@ -88,6 +88,19 @@ class SharedScreenModel(private val fileRepository: FileRepository) : ScreenMode
         }
         .stateIn(screenModelScope, SharingStarted.Lazily, emptyList())
 
+
+    private val _measureInt = MutableStateFlow<Int>(4)
+    val measureInt: StateFlow<Int> = _measureInt.asStateFlow()
+    fun setMeasureInt(measure: Int) {
+        _measureInt.value = measure
+    }
+
+    private val _silentDurationBefore = MutableStateFlow<Int>(0)
+    val silentDurationBefore: StateFlow<Int> = _silentDurationBefore.asStateFlow()
+    fun setSilentDurBefr(silent: Int) {
+        _silentDurationBefore.value = silent
+    }
+
     private val playlistFilename = "playlist.json"
     private val _playlistPaths = MutableStateFlow<List<String>>(emptyList())
     val playlistItems: StateFlow<List<DrawerItem>> = combine(_playlistPaths, _drawerItems) { paths, allItems ->
@@ -567,7 +580,7 @@ class SharedScreenModel(private val fileRepository: FileRepository) : ScreenMode
         try {
             val midiFileName = fileRepository.getFileName(newMidiFile)
             println("Opening xx129 $midiFileName")
-            _mediaPlayer = FMediaPlayer(filename = midiFileName, onFinished = {
+            _mediaPlayer = FMediaPlayer(filename = midiFileName, sharedScreenModel = this, onFinished = {
 //            _isPos.value = true
 //            _isPlay.value = false
                 _currentPos.value = 0f
@@ -666,6 +679,7 @@ class SharedScreenModel(private val fileRepository: FileRepository) : ScreenMode
         _editModeState.value = false
         _harmonyView.value = false
         setTranspositionInterval(0)
+        setSilentDurBefr(0)
         _midiMarkersList.value = emptyList()
         _tuoTimestamps.value   = emptyList()
         _searchTitle.value = ""

composeApp/src/desktopMain/kotlin/mg/dot/feufaro/midi/MidiPlayer.kt

@@ -18,6 +18,7 @@ import javax.sound.sampled.FloatControl
 
 actual class FMediaPlayer actual constructor(
     private val filename: String,
+    private val sharedScreenModel: SharedScreenModel,
     private val onFinished: () -> Unit
 ) {
     private var sequencer: Sequencer? = try {
@@ -636,7 +637,64 @@ actual class FMediaPlayer actual constructor(
         applyVoiceStates()
     }
 
+    private fun getCountInBeats(measureStr: String): Int {
+        val firstNumeratorChar = measureStr.substringBefore('/').trim()
+        return firstNumeratorChar.toIntOrNull() ?: 4
+    }
     actual fun play(){
+        if (sequencer?.isOpen == true) {
+            val currentTick = sequencer?.tickPosition ?: 0L
+            if (currentTick == 0L) {
+                playCountIn()
+            } else {
+                startMidiPlayback()
+            }
+        }
+    }
+    private var countInJob: Job? = null
+
+    private fun playCountIn() {
+        val nbMeasure = sharedScreenModel.measureInt.value
+        val nbSilent = sharedScreenModel.silentDurationBefore.value
+        countInJob?.cancel()
+        countInJob = playerScope.launch(Dispatchers.Default) {
+            if (sequencer?.isOpen == true && synthetizer?.isOpen == true) {
+                val bpm = targetBpm
+                val beatDurationMs = (60_000L / bpm).toLong()
+
+                val metronomeChannel = synthetizer?.channels?.getOrNull(9)
+                val noteEvent = 42
+                val velocity = 100
+
+                val originalMeasure = sharedScreenModel.measureInt.value
+                val nbSilent = sharedScreenModel.silentDurationBefore.value
+
+                val adjustedMeasure = when {
+                    originalMeasure == 6 -> 3
+                    originalMeasure % 2 != 0 && originalMeasure > 3 -> 3
+                    originalMeasure % 2 == 0 && originalMeasure > 4 -> 4
+                    else -> originalMeasure
+                }
+
+                val anacrouseBeats = nbSilent / 4
+                val totalBeats = if(anacrouseBeats > 5) anacrouseBeats else adjustedMeasure + anacrouseBeats
+//                println("Décompte total : $totalBeats bips ($adjustedMeasure de préparation + $anacrouseBeats d'anacrouse [$nbSilent / $4 ]) à $bpm BPM")
+
+                for (i in 1..totalBeats) {
+                    metronomeChannel?.noteOn(noteEvent, velocity)
+                    delay(100)
+                    metronomeChannel?.noteOff(noteEvent)
+
+                    delay((beatDurationMs - 100).coerceAtLeast(0L))
+                }
+
+                withContext(Dispatchers.Main) {
+                    startMidiPlayback()
+                }
+            }
+        }
+    }
+    private fun startMidiPlayback() {
         if (sequencer?.isOpen == true){
             applyBpm()
             sequencer?.start()
@@ -645,6 +703,7 @@ actual class FMediaPlayer actual constructor(
         }
     }
     actual fun pause(){
+        countInJob?.cancel()
         sequencer?.stop()
     }
     actual fun requestSync(sharedScreenModel: SharedScreenModel) {
@@ -700,6 +759,7 @@ actual class FMediaPlayer actual constructor(
 
     actual fun stop(){
         //        sequencer?.stop()
+        countInJob?.cancel()
         sequencer?.microsecondPosition = 0
         navigationJob?.cancel()
         resetNavigationFlags()