feat(player): Android queue — reorder, remove, art, auto-follow, clear — #1944

Queue screen gains: album-art thumbnails (ServerImage), drag-to-reorder via a
grip handle (offset->delta on release, mirroring the web), a remove button per
row, auto-follow of the now-playing track with a 'Jump to current' pill when
scrolled away, a clear-queue action, and a header count + total-time summary.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

android/app/src/main/java/com/fabledsword/minstrel/player/ui/QueueScreen.kt

@@ -1,18 +1,25 @@
 package com.fabledsword.minstrel.player.ui
 
+import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.gestures.detectDragGestures
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.itemsIndexed
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.FilledTonalButton
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -21,23 +28,43 @@ import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.material3.TopAppBar
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.layout.onSizeChanged
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import androidx.compose.ui.zIndex
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.navigation.NavHostController
+import com.composables.icons.lucide.ArrowDown
 import com.composables.icons.lucide.ArrowLeft
+import com.composables.icons.lucide.GripVertical
 import com.composables.icons.lucide.Lucide
+import com.composables.icons.lucide.Music
+import com.composables.icons.lucide.Trash2
 import com.composables.icons.lucide.Volume2
+import com.composables.icons.lucide.X
 import com.fabledsword.minstrel.models.TrackRef
 import com.fabledsword.minstrel.shared.formatDuration
 import com.fabledsword.minstrel.shared.widgets.EmptyState
 import com.fabledsword.minstrel.shared.widgets.LikeButton
+import com.fabledsword.minstrel.shared.widgets.ServerImage
+import kotlin.math.roundToInt
+import kotlinx.coroutines.launch
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -51,12 +78,30 @@ fun QueueScreen(
         modifier = Modifier.fillMaxSize(),
         topBar = {
             TopAppBar(
-                title = { Text("Queue") },
+                title = {
+                    Column {
+                        Text("Queue")
+                        if (state.queue.isNotEmpty()) {
+                            Text(
+                                text = queueSummary(state.queue),
+                                style = MaterialTheme.typography.bodySmall,
+                                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                            )
+                        }
+                    }
+                },
                 navigationIcon = {
                     IconButton(onClick = { navController.popBackStack() }) {
                         Icon(Lucide.ArrowLeft, contentDescription = "Back")
                     }
                 },
+                actions = {
+                    if (state.queue.isNotEmpty()) {
+                        IconButton(onClick = viewModel::clearQueue) {
+                            Icon(Lucide.Trash2, contentDescription = "Clear queue")
+                        }
+                    }
+                },
             )
         },
     ) { inner ->
@@ -73,12 +118,15 @@ fun QueueScreen(
                     likedTrackIds = likedTrackIds,
                     onJumpTo = viewModel::seekToIndex,
                     onToggleLike = viewModel::toggleLikeTrack,
+                    onMove = viewModel::moveInQueue,
+                    onRemove = viewModel::removeFromQueue,
                 )
             }
         }
     }
 }
 
+@Suppress("LongParameterList") // Compose list wiring — layout + queue callbacks, not logic.
 @Composable
 private fun QueueList(
     tracks: List<TrackRef>,
@@ -86,36 +134,90 @@ private fun QueueList(
     likedTrackIds: Set<String>,
     onJumpTo: (Int) -> Unit,
     onToggleLike: (String) -> Unit,
+    onMove: (Int, Int) -> Unit,
+    onRemove: (Int) -> Unit,
 ) {
-    // Open scrolled to the now-playing track so it's in view immediately.
-    // Seeding the initial index (rather than animating post-layout) avoids a
-    // flash of the list top; it's captured once per entry, so the view stays
-    // put as the track later auto-advances — matching "show me where I am now."
     val listState = rememberLazyListState(
         initialFirstVisibleItemIndex = currentIndex.coerceIn(0, tracks.lastIndex),
     )
-    LazyColumn(state = listState, modifier = Modifier.fillMaxSize()) {
-        itemsIndexed(items = tracks, key = { _, track -> track.id }) { index, track ->
-            QueueRow(
-                track = track,
-                isCurrent = index == currentIndex,
-                liked = track.id in likedTrackIds,
-                onClick = { onJumpTo(index) },
-                onToggleLike = { onToggleLike(track.id) },
-            )
-            HorizontalDivider()
+    val scope = rememberCoroutineScope()
+
+    // Follow the now-playing row as the track auto-advances, but only while it's
+    // near the visible window — if the user has scrolled away to browse, leave
+    // them there (the pill offers the way back). Parity with the web queue.
+    LaunchedEffect(currentIndex) {
+        if (currentIndex < 0) return@LaunchedEffect
+        val visible = listState.layoutInfo.visibleItemsInfo
+        val first = visible.firstOrNull()?.index ?: 0
+        val last = visible.lastOrNull()?.index ?: 0
+        if (currentIndex in (first - 1)..(last + 1)) {
+            listState.animateScrollToItem(currentIndex)
         }
     }
+
+    val currentVisible by remember {
+        derivedStateOf {
+            listState.layoutInfo.visibleItemsInfo.any { it.index == currentIndex }
+        }
+    }
+
+    Box(modifier = Modifier.fillMaxSize()) {
+        LazyColumn(state = listState, modifier = Modifier.fillMaxSize()) {
+            itemsIndexed(items = tracks, key = { _, track -> track.id }) { index, track ->
+                QueueRow(
+                    track = track,
+                    index = index,
+                    queueSize = tracks.size,
+                    isCurrent = index == currentIndex,
+                    liked = track.id in likedTrackIds,
+                    onClick = { onJumpTo(index) },
+                    onToggleLike = { onToggleLike(track.id) },
+                    onRemove = { onRemove(index) },
+                    onMove = onMove,
+                )
+                HorizontalDivider()
+            }
+        }
+        JumpToCurrentPill(
+            visible = currentIndex >= 0 && !currentVisible,
+            onClick = {
+                scope.launch { listState.animateScrollToItem(currentIndex.coerceAtLeast(0)) }
+            },
+            modifier = Modifier.align(Alignment.BottomCenter).padding(bottom = 16.dp),
+        )
+    }
 }
 
+@Composable
+private fun JumpToCurrentPill(
+    visible: Boolean,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    AnimatedVisibility(visible = visible, modifier = modifier) {
+        FilledTonalButton(onClick = onClick) {
+            Icon(Lucide.ArrowDown, contentDescription = null, modifier = Modifier.size(18.dp))
+            Spacer(modifier = Modifier.width(6.dp))
+            Text("Jump to current")
+        }
+    }
+}
+
+@Suppress("LongParameterList") // Compose row wiring — layout + queue callbacks, not logic.
 @Composable
 private fun QueueRow(
     track: TrackRef,
+    index: Int,
+    queueSize: Int,
     isCurrent: Boolean,
     liked: Boolean,
     onClick: () -> Unit,
     onToggleLike: () -> Unit,
+    onRemove: () -> Unit,
+    onMove: (Int, Int) -> Unit,
 ) {
+    var dragOffsetY by remember { mutableFloatStateOf(0f) }
+    var rowHeightPx by remember { mutableIntStateOf(0) }
     val highlight = if (isCurrent) {
         MaterialTheme.colorScheme.primary.copy(alpha = HIGHLIGHT_ALPHA)
     } else {
@@ -124,12 +226,23 @@ private fun QueueRow(
     Row(
         modifier = Modifier
             .fillMaxWidth()
+            .onSizeChanged { rowHeightPx = it.height }
+            .zIndex(if (dragOffsetY != 0f) 1f else 0f)
+            .graphicsLayer { translationY = dragOffsetY }
             .background(highlight)
             .clickable(onClick = onClick)
             .padding(horizontal = 16.dp, vertical = 12.dp),
         verticalAlignment = Alignment.CenterVertically,
         horizontalArrangement = Arrangement.spacedBy(12.dp),
     ) {
+        DragHandle(
+            index = index,
+            queueSize = queueSize,
+            rowHeightPx = rowHeightPx,
+            onOffsetChange = { dragOffsetY = it },
+            onMove = onMove,
+        )
+        QueueRowThumbnail(track = track)
         if (isCurrent) {
             Icon(
                 Lucide.Volume2,
@@ -137,26 +250,7 @@ private fun QueueRow(
                 tint = MaterialTheme.colorScheme.primary,
             )
         }
-        Column(modifier = Modifier.weight(1f)) {
-            Text(
-                text = track.title,
-                style = MaterialTheme.typography.bodyLarge,
-                color = MaterialTheme.colorScheme.onSurface,
-                fontWeight = if (isCurrent) FontWeight.Medium else FontWeight.Normal,
-                maxLines = 1,
-                overflow = TextOverflow.Ellipsis,
-            )
-            val subtitle = queueSubtitle(track)
-            if (subtitle.isNotEmpty()) {
-                Text(
-                    text = subtitle,
-                    style = MaterialTheme.typography.bodySmall,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                    maxLines = 1,
-                    overflow = TextOverflow.Ellipsis,
-                )
-            }
-        }
+        QueueRowText(track = track, isCurrent = isCurrent, modifier = Modifier.weight(1f))
         if (track.durationSec > 0) {
             Text(
                 text = formatDuration(track.durationSec),
@@ -165,6 +259,94 @@ private fun QueueRow(
             )
         }
         LikeButton(liked = liked, onToggle = onToggleLike)
+        IconButton(onClick = onRemove) {
+            Icon(Lucide.X, contentDescription = "Remove from queue")
+        }
+    }
+}
+
+@Composable
+private fun DragHandle(
+    index: Int,
+    queueSize: Int,
+    rowHeightPx: Int,
+    onOffsetChange: (Float) -> Unit,
+    onMove: (Int, Int) -> Unit,
+) {
+    // Mirrors the web queue: the row follows the finger during a drag, then on
+    // release we translate the accumulated offset into a row delta and reorder.
+    var offset by remember { mutableFloatStateOf(0f) }
+    Icon(
+        Lucide.GripVertical,
+        contentDescription = "Reorder track",
+        tint = MaterialTheme.colorScheme.onSurfaceVariant,
+        modifier = Modifier.pointerInput(index, queueSize, rowHeightPx) {
+            detectDragGestures(
+                onDrag = { change, dragAmount ->
+                    change.consume()
+                    offset += dragAmount.y
+                    onOffsetChange(offset)
+                },
+                onDragEnd = {
+                    val delta = if (rowHeightPx > 0) (offset / rowHeightPx).roundToInt() else 0
+                    val target = (index + delta).coerceIn(0, queueSize - 1)
+                    if (target != index) onMove(index, target)
+                    offset = 0f
+                    onOffsetChange(0f)
+                },
+                onDragCancel = {
+                    offset = 0f
+                    onOffsetChange(0f)
+                },
+            )
+        },
+    )
+}
+
+@Composable
+private fun QueueRowThumbnail(track: TrackRef) {
+    Box(
+        modifier = Modifier
+            .size(48.dp)
+            .clip(RoundedCornerShape(4.dp))
+            .background(MaterialTheme.colorScheme.surfaceVariant),
+        contentAlignment = Alignment.Center,
+    ) {
+        ServerImage(
+            url = track.coverUrl,
+            contentDescription = null,
+            modifier = Modifier.size(48.dp),
+        ) {
+            Icon(
+                Lucide.Music,
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        }
+    }
+}
+
+@Composable
+private fun QueueRowText(track: TrackRef, isCurrent: Boolean, modifier: Modifier = Modifier) {
+    Column(modifier = modifier) {
+        Text(
+            text = track.title,
+            style = MaterialTheme.typography.bodyLarge,
+            color = MaterialTheme.colorScheme.onSurface,
+            fontWeight = if (isCurrent) FontWeight.Medium else FontWeight.Normal,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+        )
+        val subtitle = queueSubtitle(track)
+        if (subtitle.isNotEmpty()) {
+            Text(
+                text = subtitle,
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+            )
+        }
     }
 }
 
@@ -173,4 +355,18 @@ private fun queueSubtitle(track: TrackRef): String = listOf(track.artistName, tr
     .filter { it.isNotEmpty() }
     .joinToString(" · ")
 
+/** "N tracks · 12 min" header summary. */
+private fun queueSummary(tracks: List<TrackRef>): String {
+    val minutes = tracks.sumOf { it.durationSec } / SECONDS_PER_MINUTE
+    val length = if (minutes >= MINUTES_PER_HOUR) {
+        "${minutes / MINUTES_PER_HOUR}h ${minutes % MINUTES_PER_HOUR}m"
+    } else {
+        "$minutes min"
+    }
+    val noun = if (tracks.size == 1) "track" else "tracks"
+    return "${tracks.size} $noun · $length"
+}
+
 private const val HIGHLIGHT_ALPHA = 0.12f
+private const val SECONDS_PER_MINUTE = 60
+private const val MINUTES_PER_HOUR = 60