From 5b493e5b4e0b50bf07554cdfe01704d6f160bcc0 Mon Sep 17 00:00:00 2001
From: Hasinjato <hasinarak3@gmail.com>
Date: Tue, 8 Sep 2026 10:32:07 +0300
Subject: [PATCH] Implement A-B looping based on measure - Android

---
 .../kotlin/mg/dot/feufaro/midi/MidiPlayer.kt  | 42 +++++++++++++++----
 .../mg/dot/feufaro/solfa/TimeUnitObject.kt    |  4 +-
 .../feufaro/viewmodel/SharedScreenModel.kt    |  8 ++--
 3 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/composeApp/src/androidMain/kotlin/mg/dot/feufaro/midi/MidiPlayer.kt b/composeApp/src/androidMain/kotlin/mg/dot/feufaro/midi/MidiPlayer.kt
index 1e69b44..6a51f48 100644
--- a/composeApp/src/androidMain/kotlin/mg/dot/feufaro/midi/MidiPlayer.kt
+++ b/composeApp/src/androidMain/kotlin/mg/dot/feufaro/midi/MidiPlayer.kt
@@ -391,10 +391,9 @@ actual class FMediaPlayer actual constructor(
                 lastEventNano = System.nanoTime()
 
                 // A-B loop
-                if (isLoopingAB && pointA >= 0 && pointB > pointA &&
-                    ticksToMs(currentTickPos) >= pointB) {
+                if (isLoopingAB && pointA >= 0L && pointB > pointA && currentTickPos >= pointB) {
                     allNotesOff()
-                    currentTickPos = msToTicks(pointA)
+                    currentTickPos = pointA
                     clockNano = System.nanoTime()
                     clockTick = currentTickPos
                     idx = events.indexOfFirst { it.tickAbsolute >= currentTickPos }
@@ -992,13 +991,38 @@ actual class FMediaPlayer actual constructor(
         startNavigationMonitor(sharedScreenModel)
         startSyncLoop(sharedScreenModel)
     }
-    actual fun setPointA() { pointA = getCurrentPosition() }
-    actual fun setPointB() {
-        pointB = getCurrentPosition()
-        if (pointB > pointA && pointA != -1L) isLoopingAB = true
+    actual fun setPointA(grid: Int) {
+        val tick = grid.toLong() * resolution
+        pointA = tick
+
+        val currentB = sharedScreenModel.loopingState.value.second
+        sharedScreenModel.updateLoopingState(grid, currentB)
     }
-    actual fun clearLoop() { isLoopingAB = false; pointA = -1L; pointB = -1L }
-    actual fun getLoopState() = Triple(pointA, pointB, isLoopingAB)
+
+    actual fun setPointB(grid: Int) {
+        val tick = (((grid + 1).toDouble() * resolution) - 1.0).toLong()
+        pointB = tick.coerceAtLeast(0L)
+
+        val currentA = sharedScreenModel.loopingState.value.first
+        sharedScreenModel.updateLoopingState(currentA, grid)
+
+        if (currentA != -1) {
+            seekToGrid(currentA)
+        }
+
+        if (pointB > pointA && pointA != -1L) {
+            isLoopingAB = true
+        }
+    }
+
+    actual fun clearLoop() {
+        isLoopingAB = false
+        pointA = -1
+        pointB = -1
+    }
+
+    actual fun getLoopState() = Triple(pointA.toLong(), pointB.toLong(), isLoopingAB)
+
     actual fun toggleVoice(index: Int) { applyVoiceStates() }
     private fun saveVoicesVolumes() {
         val data = voiceVolumes.joinToString(",")
diff --git a/composeApp/src/commonMain/kotlin/mg/dot/feufaro/solfa/TimeUnitObject.kt b/composeApp/src/commonMain/kotlin/mg/dot/feufaro/solfa/TimeUnitObject.kt
index c39278d..deb9180 100644
--- a/composeApp/src/commonMain/kotlin/mg/dot/feufaro/solfa/TimeUnitObject.kt
+++ b/composeApp/src/commonMain/kotlin/mg/dot/feufaro/solfa/TimeUnitObject.kt
@@ -639,7 +639,6 @@ fun LazyVerticalGridTUO(
 
     val platform = getPlatform()
     val isAndroid = platform.name.startsWith("Android")
-    val loopingState by sharedScreenModel.loopingState.collectAsState()
     val activeIndex by sharedScreenModel.activeIndex.collectAsState()
     val loopState by produceState(Triple(-1L, -1L, false), sharedScreenModel.mediaPlayer) {
         while (true) {
@@ -1011,7 +1010,8 @@ fun LazyVerticalGridTUO(
                     Row(modifier = Modifier.fillMaxWidth()) {
                         measureTUOs.forEachIndexed { indexInMeasure, oneTUO ->
                             val globalIndex = (measureIndex * gridColumnCount) + indexInMeasure
-                            val pointA =  loopingState.first
+                            val loopingState by sharedScreenModel.loopingState.collectAsState()
+                            val pointA = loopingState.first
                             val pointB = loopingState.second
 
                             val isInABrange = if (pointA != -1 && pointB != -1) {
diff --git a/composeApp/src/commonMain/kotlin/mg/dot/feufaro/viewmodel/SharedScreenModel.kt b/composeApp/src/commonMain/kotlin/mg/dot/feufaro/viewmodel/SharedScreenModel.kt
index 39d52b9..be6ebe1 100644
--- a/composeApp/src/commonMain/kotlin/mg/dot/feufaro/viewmodel/SharedScreenModel.kt
+++ b/composeApp/src/commonMain/kotlin/mg/dot/feufaro/viewmodel/SharedScreenModel.kt
@@ -445,11 +445,13 @@ class SharedScreenModel(private val fileRepository: FileRepository) : ScreenMode
         }
     }
 
-    private val _loopingState = MutableStateFlow(Pair(-1, -1))
-    val loopingState: StateFlow<Pair<Int, Int>> = _loopingState.asStateFlow()
+    data class LoopRange(val first: Int = -1, val second: Int = -1)
+
+    private val _loopingState = MutableStateFlow(LoopRange())
+    val loopingState: StateFlow<LoopRange> = _loopingState.asStateFlow()
 
     fun updateLoopingState(a: Int, b: Int) {
-        _loopingState.value = Pair(a, b)
+        _loopingState.value = LoopRange(a, b)
     }
 
     fun calculateSmartPointB(rawPointB: Int, isZeroIndexed: Boolean = false): Int {