feat: offline playlist & album downloader

Dockerfile.release

@@ -0,0 +1,64 @@
+# syntax=docker/dockerfile:1
+FROM ubuntu:22.04
+
+ENV DEBIAN_FRONTEND=noninteractive \
+    FLUTTER_SUPPRESS_ANALYTICS=1 \
+    PUB_CACHE=/opt/pub-cache \
+    GRADLE_USER_HOME=/opt/gradle-cache
+
+# ── System deps ────────────────────────────────────────────────────────────────
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        openjdk-17-jdk-headless \
+        wget curl git unzip xz-utils zip \
+        libglu1-mesa ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+
+ENV JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64 \
+    PATH=/usr/lib/jvm/java-17-openjdk-amd64/bin:$PATH
+
+# ── Android SDK (including cmake so Gradle never tries to auto-install it) ─────
+ENV ANDROID_SDK_ROOT=/opt/android-sdk \
+    ANDROID_HOME=/opt/android-sdk
+RUN mkdir -p /opt/android-sdk/cmdline-tools \
+    && wget -q https://dl.google.com/android/repository/commandlinetools-linux-11076708_latest.zip \
+             -O /tmp/cmdline-tools.zip \
+    && unzip -q /tmp/cmdline-tools.zip -d /opt/android-sdk/cmdline-tools \
+    && mv /opt/android-sdk/cmdline-tools/cmdline-tools \
+          /opt/android-sdk/cmdline-tools/latest \
+    && rm /tmp/cmdline-tools.zip
+
+ENV PATH=/opt/android-sdk/cmdline-tools/latest/bin:/opt/android-sdk/platform-tools:$PATH
+
+RUN yes | sdkmanager --licenses > /dev/null 2>&1 || true \
+    && sdkmanager \
+        "platform-tools" \
+        "platforms;android-35" \
+        "build-tools;35.0.0" \
+        "ndk;27.0.12077973" \
+        "cmake;3.22.1"
+
+# ── Flutter SDK ────────────────────────────────────────────────────────────────
+RUN git clone --depth 1 --branch stable \
+        https://github.com/flutter/flutter.git /opt/flutter \
+    && git config --global --add safe.directory /opt/flutter
+
+ENV PATH=/opt/flutter/bin:$PATH
+
+RUN flutter --version
+RUN yes | flutter doctor --android-licenses > /dev/null 2>&1 || true
+
+# ── App source & build ─────────────────────────────────────────────────────────
+WORKDIR /app
+COPY . .
+
+# Cache mounts keep Gradle + pub downloads outside the overlay layer,
+# preventing "No space left on device" errors on large Gradle transform sets.
+RUN --mount=type=cache,target=/opt/gradle-cache \
+    --mount=type=cache,target=/opt/pub-cache \
+    flutter pub get
+
+RUN --mount=type=cache,target=/opt/gradle-cache \
+    --mount=type=cache,target=/opt/pub-cache \
+    flutter build apk --release
+
+# Output: /app/build/app/outputs/flutter-apk/app-release.apk

android/gradle.properties

@@ -1,2 +1,3 @@
 org.gradle.jvmargs=-Xmx8G -XX:MaxMetaspaceSize=4G -XX:ReservedCodeCacheSize=512m -XX:+HeapDumpOnOutOfMemoryError
 android.useAndroidX=true
+android.newDsl=false

build-release-apk.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# Build a release APK using Docker (data stored in /rw/docker).
+# Usage:  ./build-release-apk.sh [output-dir]
+# The APK is copied to <output-dir> (default: ./release-apk)
+set -euo pipefail
+
+OUTPUT_DIR="${1:-$(pwd)/release-apk}"
+IMAGE_TAG="musly-release-builder"
+CONTAINER_NAME="musly-apk-build"
+
+cd "$(dirname "$0")"
+
+echo "==> Building Docker image: $IMAGE_TAG"
+sudo docker build -f Dockerfile.release -t "$IMAGE_TAG" .
+
+echo "==> Extracting APK from image"
+sudo docker rm -f "$CONTAINER_NAME" 2>/dev/null || true
+sudo docker create --name "$CONTAINER_NAME" "$IMAGE_TAG" echo done
+mkdir -p "$OUTPUT_DIR"
+sudo docker cp \
+    "$CONTAINER_NAME:/app/build/app/outputs/flutter-apk/app-release.apk" \
+    "$OUTPUT_DIR/musly-release.apk"
+sudo docker rm -f "$CONTAINER_NAME"
+
+echo ""
+echo "==> APK ready: $OUTPUT_DIR/musly-release.apk"
+ls -lh "$OUTPUT_DIR/musly-release.apk"

lib/providers/player_provider.dart

@@ -1124,6 +1124,12 @@ class PlayerProvider extends ChangeNotifier {
       notifyListeners();
     });
 
+    // Resume any playlists that were queued for download but interrupted
+    _offlineService.initialize().then((_) {
+      _offlineService.resumeIncompleteDownloads(_subsonicService);
+    });
+
+
     _storageService.getRepeatMode().then((saved) {
       _repeatMode =
           RepeatMode.values[saved.clamp(0, RepeatMode.values.length - 1)];

lib/screens/album_screen.dart

@@ -24,12 +24,36 @@ class _AlbumScreenState extends State<AlbumScreen> {
   Album? _album;
   List<Song> _songs = [];
   bool _isLoading = true;
-  bool _isDownloading = false;
+
+  bool _allDownloaded = false;
+  bool _isQueued = false;
 
   @override
   void initState() {
     super.initState();
     _loadAlbum();
+    OfflineService().downloadedPlaylistIds.addListener(_updateDownloadState);
+    OfflineService().queuedPlaylistIds.addListener(_updateDownloadState);
+  }
+
+  @override
+  void dispose() {
+    OfflineService().downloadedPlaylistIds.removeListener(_updateDownloadState);
+    OfflineService().queuedPlaylistIds.removeListener(_updateDownloadState);
+    super.dispose();
+  }
+
+  void _updateDownloadState() {
+    if (!mounted || _album == null) return;
+    final offline = OfflineService();
+    final allDown = offline.downloadedPlaylistIds.value.contains(_album!.id);
+    final queued = offline.queuedPlaylistIds.value.contains(_album!.id);
+    if (allDown != _allDownloaded || queued != _isQueued) {
+      setState(() {
+        _allDownloaded = allDown;
+        _isQueued = queued;
+      });
+    }
   }
 
   Future<void> _loadAlbum() async {
@@ -62,6 +86,7 @@ class _AlbumScreenState extends State<AlbumScreen> {
           _songs = songs;
           _isLoading = false;
         });
+        _updateDownloadState();
       }
     } catch (e) {
       if (mounted) {
@@ -84,41 +109,74 @@ class _AlbumScreenState extends State<AlbumScreen> {
   }
 
   Future<void> _downloadAlbum() async {
-    if (_songs.isEmpty) return;
-
-    final subsonicService = Provider.of<SubsonicService>(
-      context,
-      listen: false,
-    );
+    if (_songs.isEmpty || _album == null) return;
     final offlineService = OfflineService();
+    final subsonicService = Provider.of<SubsonicService>(context, listen: false);
     await offlineService.initialize();
-
-    setState(() => _isDownloading = true);
-
-    offlineService.startBackgroundDownload(_songs, subsonicService).then((_) {
-      if (mounted) {
-        setState(() => _isDownloading = false);
-        ScaffoldMessenger.of(context).showSnackBar(
-          SnackBar(
-            content: Text(
-              'Downloaded ${_songs.length} songs from ${_album!.name}',
-            ),
-            duration: const Duration(seconds: 3),
-          ),
-        );
-      }
-    });
-
+    offlineService.queuePlaylistDownload(_album!.id, _songs, subsonicService);
     if (mounted) {
       ScaffoldMessenger.of(context).showSnackBar(
         SnackBar(
-          content: Text('Downloading ${_songs.length} songs in background…'),
+          content: Text('Queued ${_songs.length} songs for download…'),
           duration: const Duration(seconds: 2),
         ),
       );
     }
   }
 
+  Future<void> _cancelDownload() async {
+    if (_album == null) return;
+    await OfflineService().cancelPlaylistDownload(_album!.id);
+  }
+
+  Future<void> _removeDownloads() async {
+    if (_songs.isEmpty || _album == null) return;
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: const Text('Remove downloads?'),
+        content: Text('Remove all ${_songs.length} downloaded songs from "${_album!.name}"?'),
+        actions: [
+          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('Cancel')),
+          TextButton(
+            onPressed: () => Navigator.pop(ctx, true),
+            child: const Text('Remove', style: TextStyle(color: Colors.red)),
+          ),
+        ],
+      ),
+    );
+    if (confirmed == true && mounted) {
+      await OfflineService().cancelPlaylistDownload(_album!.id);
+      await OfflineService().deletePlaylistDownloads(_songs);
+    }
+  }
+
+  Widget _buildDownloadButton(BuildContext context) {
+    if (_allDownloaded) {
+      return IconButton(
+        tooltip: 'Downloaded — tap to remove',
+        onPressed: _removeDownloads,
+        icon: const Icon(Icons.cloud_done, color: Colors.green),
+      );
+    }
+    if (_isQueued) {
+      return IconButton(
+        tooltip: 'Downloading — tap to cancel',
+        onPressed: _cancelDownload,
+        icon: const SizedBox(
+          width: 20,
+          height: 20,
+          child: CircularProgressIndicator(strokeWidth: 2),
+        ),
+      );
+    }
+    return IconButton(
+      tooltip: 'Download album',
+      onPressed: _downloadAlbum,
+      icon: const Icon(CupertinoIcons.cloud_download),
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
@@ -224,39 +282,50 @@ class _AlbumScreenState extends State<AlbumScreen> {
                   onPressed: () => Navigator.pop(context),
                 ),
                 flexibleSpace: FlexibleSpaceBar(
-                  background: Stack(
-                    fit: StackFit.expand,
-                    children: [
-                      Padding(
-                        padding: EdgeInsets.only(
-                          top: MediaQuery.of(context).padding.top + 40,
-                          left: ScreenHelper.isSmallScreen(context) ? 24 : 40,
-                          right: ScreenHelper.isSmallScreen(context) ? 24 : 40,
-                          bottom: ScreenHelper.isSmallScreen(context) ? 60 : 80,
-                        ),
-                        child: AlbumArtwork(
-                          coverArt: _album!.coverArt,
-                          size: ScreenHelper.isSmallScreen(context) ? 200 : 280,
-                          borderRadius: 10,
-                          preserveAspectRatio: true,
-                        ),
-                      ),
-                    ],
+                  background: ValueListenableBuilder<Set<String>>(
+                    valueListenable: OfflineService().downloadedPlaylistIds,
+                    builder: (context, downloaded, _) {
+                      final allDownloaded = _album != null && downloaded.contains(_album!.id);
+                      return Stack(
+                        fit: StackFit.expand,
+                        children: [
+                          Padding(
+                            padding: EdgeInsets.only(
+                              top: MediaQuery.of(context).padding.top + 40,
+                              left: ScreenHelper.isSmallScreen(context) ? 24 : 40,
+                              right: ScreenHelper.isSmallScreen(context) ? 24 : 40,
+                              bottom: ScreenHelper.isSmallScreen(context) ? 60 : 80,
+                            ),
+                            child: AlbumArtwork(
+                              coverArt: _album!.coverArt,
+                              size: ScreenHelper.isSmallScreen(context) ? 200 : 280,
+                              borderRadius: 10,
+                              preserveAspectRatio: true,
+                            ),
+                          ),
+                          if (allDownloaded)
+                            Positioned(
+                              bottom: 86,
+                              right: 46,
+                              child: Container(
+                                decoration: const BoxDecoration(
+                                  color: Colors.white,
+                                  shape: BoxShape.circle,
+                                ),
+                                child: const Icon(
+                                  Icons.check_circle,
+                                  color: Colors.green,
+                                  size: 28,
+                                ),
+                              ),
+                            ),
+                        ],
+                      );
+                    },
                   ),
                 ),
                 actions: [
-                  if (!isOffline)
-                    IconButton(
-                      tooltip: 'Download album',
-                      onPressed: _isDownloading ? null : _downloadAlbum,
-                      icon: _isDownloading
-                          ? const SizedBox(
-                              width: 20,
-                              height: 20,
-                              child: CircularProgressIndicator(strokeWidth: 2),
-                            )
-                          : const Icon(CupertinoIcons.cloud_download),
-                    ),
+                  if (!isOffline) _buildDownloadButton(context),
                 ],
               ),
               SliverToBoxAdapter(