voice: real pause (saves position), waveform tap seek, resume from position

- AudioRecorderManager: playFromPosition(startMs), pausePlayback, elapsedMs tracking
  playVoiceFile now delegates to playFromPosition. fade skipped PCM frames on seek.
- ViewModel: playVoiceMessage with pause toggle, seekVoice method
- VoiceBubble: click tap on waveform → seek, pause state (⏸ keeps cursor visible)
  Webform canvas with detectTapGestures for seek input

tools/chatgui-android/app/src/main/java/com/utun/chat/data/AudioRecorderManager.kt

@@ -181,11 +181,19 @@ class AudioRecorderManager {
     }
 
     @Volatile private var playing = false
+    @Volatile var isPaused = false; private set
+    @Volatile var elapsedMs: Int = 0; private set
+    var pausedElapsedMs: Int = 0; private set
     private var playThread: Thread? = null
+    private var currentPlayPath: String? = null
 
-    fun playVoiceFile(filePath: String, onProgress: (Float) -> Unit = {}, onComplete: () -> Unit = {}) {
-        if (playing) stopPlayback()
-        playing = true
+    fun playVoiceFile(filePath: String, onProgress: ((Float) -> Unit)? = null, onComplete: () -> Unit = {}) {
+        playFromPosition(filePath, 0, onProgress, onComplete)
+    }
+
+    fun playFromPosition(filePath: String, startMs: Int, onProgress: ((Float) -> Unit)? = null, onComplete: () -> Unit = {}) {
+        stopPlayback()
+        isPaused = false; elapsedMs = startMs; playing = true; currentPlayPath = filePath
 
         playThread = Thread {
             try {
@@ -193,10 +201,21 @@ class AudioRecorderManager {
                 val handle = NativeLib.voiceDecodeOpen(filePath, info)
                 if (handle == 0L) {
                     LogManager.addLog("ERROR", "AudioPlayer", "decode open failed: $filePath")
-                    playing = false; return@Thread
+                    playing = false; onComplete(); return@Thread
                 }
                 val sampleRate = info[0]; val channels = info[1]; val totalSamples = info[2]
 
+                /* skip to startMs by decoding and discarding frames */
+                val frameSamples = FRAME_SAMPLES * channels
+                val skipFrames = startMs / FRAME_MS
+                val skipBuf = ShortArray(frameSamples)
+                var skippedSamples = 0L
+                for (f in 0 until skipFrames) {
+                    val dec = NativeLib.voiceDecodeRead(handle, skipBuf)
+                    if (dec <= 0) break
+                    skippedSamples += dec
+                }
+
                 val bufSize = AudioTrack.getMinBufferSize(
                     sampleRate,
                     if (channels == 2) AudioFormat.CHANNEL_OUT_STEREO else AudioFormat.CHANNEL_OUT_MONO,
@@ -204,16 +223,13 @@ class AudioRecorderManager {
                 )
 
                 val track = AudioTrack(
-                    AudioManager.STREAM_MUSIC,
-                    sampleRate,
+                    AudioManager.STREAM_MUSIC, sampleRate,
                     if (channels == 2) AudioFormat.CHANNEL_OUT_STEREO else AudioFormat.CHANNEL_OUT_MONO,
-                    AudioFormat.ENCODING_PCM_16BIT,
-                    bufSize,
-                    AudioTrack.MODE_STREAM
+                    AudioFormat.ENCODING_PCM_16BIT, bufSize, AudioTrack.MODE_STREAM
                 )
                 track.play()
 
-                val pcm = ShortArray(FRAME_SAMPLES * channels)
+                val pcm = ShortArray(frameSamples)
                 var readTotal = 0L
                 var read: Int
                 while (playing) {
@@ -221,22 +237,28 @@ class AudioRecorderManager {
                     if (read <= 0) break
                     track.write(pcm, 0, read)
                     readTotal += read
-                    if (totalSamples > 0) onProgress(readTotal.toFloat() / totalSamples.toFloat())
+                    val total = (skippedSamples + readTotal).toFloat() / (totalSamples * channels).coerceAtLeast(1).toFloat()
+                    elapsedMs = startMs + (readTotal * FRAME_MS / frameSamples).toInt()
+                    onProgress?.invoke(total)
                 }
-                track.stop()
-                track.release()
+                track.stop(); track.release()
                 NativeLib.voiceDecodeClose(handle)
             } catch (e: Exception) {
                 LogManager.addLog("ERROR", "AudioPlayer", "play error: ${e.message}")
             }
-            playing = false
+            playing = false; isPaused = false; currentPlayPath = null
             onComplete()
         }.apply { start() }
     }
 
+    fun pausePlayback() {
+        pausedElapsedMs = elapsedMs
+        isPaused = true; playing = false
+        playThread?.join(500); playThread = null
+    }
+
     fun stopPlayback() {
-        playing = false
-        playThread?.join(500)
-        playThread = null
+        playing = false; isPaused = false; pausedElapsedMs = 0
+        playThread?.join(500); playThread = null
     }
 }

tools/chatgui-android/app/src/main/java/com/utun/chat/ui/components/MessageBubble.kt

@@ -20,6 +20,7 @@ import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.foundation.gestures.detectTapGestures
 import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalDensity
@@ -31,7 +32,8 @@ import com.utun.chat.data.NativeLib
 import kotlinx.coroutines.delay
 
 @Composable
-fun MessageBubble(message: Message, onPlayVoice: (String, () -> Unit) -> Unit = { _, _ -> }) {
+fun MessageBubble(message: Message, onPlayVoice: (String, () -> Unit, () -> Unit) -> Unit = { _, _, _ -> },
+                   onSeekVoice: (String, Int, () -> Unit) -> Unit = { _, _, _ -> }) {
     val bgColor = if (message.isOutgoing) Color(0xFF4A90D9) else Color(0xFFE8E8E8)
     val textColor = if (message.isOutgoing) Color.White else Color.Black
     val alignment = if (message.isOutgoing) Arrangement.End else Arrangement.Start
@@ -56,7 +58,7 @@ fun MessageBubble(message: Message, onPlayVoice: (String, () -> Unit) -> Unit =
             Spacer(Modifier.height(2.dp))
 
             when {
-                isVoice -> VoiceBubble(message, textColor, onPlayVoice)
+                isVoice -> VoiceBubble(message, textColor, onPlayVoice, onSeekVoice)
                 isMedia -> Text("\uD83D\uDCC4 ${message.text}", fontSize = 15.sp, color = textColor)
                 else -> {
                     Text(message.author, fontSize = 13.sp, fontWeight = FontWeight.Bold, color = textColor.copy(alpha = 0.7f))
@@ -78,23 +80,26 @@ fun MessageBubble(message: Message, onPlayVoice: (String, () -> Unit) -> Unit =
     }
 }
 @Composable
-private fun VoiceBubble(message: Message, textColor: Color, onPlay: (String, () -> Unit) -> Unit) {
+private fun VoiceBubble(message: Message, textColor: Color,
+                         onPlay: (String, () -> Unit, () -> Unit) -> Unit,
+                         onSeek: (String, Int, () -> Unit) -> Unit) {
     val wf = message.waveform  // List<Float> 0..1, 100 elements
     val wfCount = wf.size
     val durMs = message.voiceDurationMs
     var playing by remember { mutableStateOf(false) }
+    var paused by remember { mutableStateOf(false) }
     var elapsedMs by remember { mutableStateOf(0) }
     var progress by remember { mutableStateOf(0f) }
 
-    /* auto-reset on complete */
-    val onDone = remember { { playing = false; elapsedMs = 0; progress = 0f } }
+    val onDone = remember { { playing = false; paused = false; elapsedMs = 0; progress = 0f } }
+    val onPaused = remember { { paused = true; playing = false } }
 
     /* elapsed timer while playing */
     LaunchedEffect(playing) {
-        if (playing) {
-            val start = System.currentTimeMillis()
-            while (playing) {
-                elapsedMs = (System.currentTimeMillis() - start).toInt()
+        if (playing && !paused) {
+            val start = System.currentTimeMillis() - elapsedMs
+            while (playing && !paused) {
+                elapsedMs = (System.currentTimeMillis() - start).toInt().coerceIn(0, durMs)
                 if (durMs > 0) progress = (elapsedMs.toFloat() / durMs.toFloat()).coerceIn(0f, 1f)
                 delay(80)
             }
@@ -108,47 +113,52 @@ private fun VoiceBubble(message: Message, textColor: Color, onPlay: (String, ()
                 modifier = Modifier.size(32.dp).background(Color.White, CircleShape)
                     .clickable {
                         if (message.filePath.isNotEmpty()) {
-                            playing = true; elapsedMs = 0; progress = 0f
-                            onPlay(message.filePath, onDone)
+                            if (playing && !paused) {
+                                onPlay(message.filePath, onDone, onPaused)
+                            } else {
+                                playing = true; paused = false
+                                onPlay(message.filePath, onDone, onPaused)
+                            }
                         }
                     },
                 contentAlignment = Alignment.Center
             ) {
-                Text(if (playing) "\u23F8" else "\u25B6", fontSize = 14.sp, color = Color.Black)
+                Text(if (playing && !paused) "\u23F8" else "\u25B6", fontSize = 14.sp, color = Color.Black)
             }
             Spacer(Modifier.width(8.dp))
 
-            /* Waveform */
+            /* Waveform with seek on tap */
             if (wfCount >= 2) {
-                Canvas(modifier = Modifier.weight(1f).height(28.dp)) {
+                Canvas(modifier = Modifier.weight(1f).height(28.dp)
+                    .pointerInput(message.filePath) {
+                        detectTapGestures { offset ->
+                            if (message.filePath.isEmpty()) return@detectTapGestures
+                            val seekFrac = (offset.x / size.width).coerceIn(0f, 1f)
+                            val seekMs = (seekFrac * durMs).toInt()
+                            playing = true; paused = false; elapsedMs = seekMs; progress = seekFrac
+                            onSeek(message.filePath, seekMs, onDone)
+                        }
+                    }
+                ) {
                     val barW = size.width / wfCount
                     val ph = size.height
-                    val playedIdx = if (playing && progress > 0f) (progress * wfCount).toInt() else 0
+                    val showCursor = playing && !paused
+                    val playedIdx = if (showCursor && progress > 0f) (progress * wfCount).toInt() else 0
                     for (i in 0 until wfCount) {
                         val level = wf[i].coerceIn(0f, 1f)
                         val barH = (2f + level * (ph - 2f)).coerceAtMost(ph)
                         val x = i.toFloat() * barW
                         val y = ph - barH
-                        val played = playing && i < playedIdx
+                        val played = showCursor && i < playedIdx
                         drawRect(
-                            color = when {
-                                played -> Color.White
-                                playing -> Color(0xFFCCCCD4).copy(alpha = 0.8f)
-                                else -> Color(0xFFCCCCD4).copy(alpha = 0.8f)
-                            },
+                            color = when { played -> Color.White; else -> Color(0xFFCCCCD4).copy(alpha = 0.8f) },
                             topLeft = Offset(x, y),
                             size = Size(barW * 0.75f, barH)
                         )
                     }
-                    /* yellow cursor line */
-                    if (playing && progress > 0f && progress < 1f) {
+                    if (showCursor && progress > 0f && progress < 1f) {
                         val cursorX = progress * size.width
-                        drawLine(
-                            color = Color(0xFFFFD600),
-                            start = Offset(cursorX, 0f),
-                            end = Offset(cursorX, ph),
-                            strokeWidth = 2.5f
-                        )
+                        drawLine(Color(0xFFFFD600), Offset(cursorX, 0f), Offset(cursorX, ph), strokeWidth = 2.5f)
                     }
                 }
             }
@@ -163,7 +173,7 @@ private fun VoiceBubble(message: Message, textColor: Color, onPlay: (String, ()
             verticalAlignment = Alignment.Bottom
         ) {
             Text(
-                if (playing) "${formatDurationMs(elapsedMs)} / ${formatDurationMs(durMs)}"
+                if (playing && !paused) "${formatDurationMs(elapsedMs)} / ${formatDurationMs(durMs)}"
                 else formatDurationMs(durMs),
                 fontSize = 12.sp,
                 color = textColor.copy(alpha = 0.55f)

tools/chatgui-android/app/src/main/java/com/utun/chat/ui/screens/ChatScreen.kt

@@ -63,9 +63,13 @@ fun ChatScreen(
             state = listState
         ) {
             items(messages.size) { idx ->
-                MessageBubble(messages[idx], onPlayVoice = { path, onDone ->
-                    viewModel.playVoiceMessage(path, onDone)
-                })
+                MessageBubble(messages[idx],
+                    onPlayVoice = { path, onDone, onPaused ->
+                        viewModel.playVoiceMessage(path, onDone, onPaused)
+                    },
+                    onSeekVoice = { path, seekMs, onDone ->
+                        viewModel.seekVoice(path, seekMs, onDone)
+                    })
             }
             item { Spacer(Modifier.height(8.dp)) }
         }

tools/chatgui-android/app/src/main/java/com/utun/chat/viewmodel/ChatViewModel.kt

@@ -266,20 +266,26 @@ class ChatViewModel : ViewModel() {
 
     private var _currentPlayingPath: String? = null
 
-    fun playVoiceMessage(filePath: String, onComplete: () -> Unit) {
+    fun playVoiceMessage(filePath: String, onDone: () -> Unit, onPaused: () -> Unit) {
         if (_currentPlayingPath == filePath) {
-            audioRecorder.stopPlayback()
-            _currentPlayingPath = null
-            onComplete()
+            if (audioRecorder.isPaused) {
+                audioRecorder.playFromPosition(filePath, audioRecorder.pausedElapsedMs, onComplete = onDone)
+            } else {
+                audioRecorder.pausePlayback()
+                onPaused()
+            }
             return
         }
         audioRecorder.stopPlayback()
         _currentPlayingPath = filePath
         LogManager.addLog("INFO", "VM", "play voice: $filePath")
-        audioRecorder.playVoiceFile(filePath, onComplete = {
-            _currentPlayingPath = null
-            onComplete()
-        })
+        audioRecorder.playVoiceFile(filePath, onComplete = { _currentPlayingPath = null; onDone() })
+    }
+
+    fun seekVoice(filePath: String, seekMs: Int, onDone: () -> Unit) {
+        audioRecorder.stopPlayback()
+        _currentPlayingPath = filePath
+        audioRecorder.playFromPosition(filePath, seekMs, onComplete = onDone)
     }
 
     fun clearState() {