feat(player): add IQueueService orchestrating album playback above the single-slot player (P11 11.F)

Queue owns ordered tracks, current index, skip-fwd/back, and auto-advance via the player's TrackEnded hook; binds through Attach (no ctor growth, no service-locator). Player-bar skip controls; empty-queue play unchanged. Adds QueueService unit tests.
2026-06-16 00:04:44 -04:00
parent 56e205082d
commit 2b42e01cd0
14 changed files with 771 additions and 2 deletions
@@ -21,6 +21,10 @@ else
                                         Fixed="Fixed"
                                         TogglePlayPause="@TogglePlayPause"
                                         Stop="@Stop"
+                                         HasNext="HasNext"
+                                         HasPrevious="HasPrevious"
+                                         SkipNext="@SkipNext"
+                                         SkipPrevious="@SkipPrevious"
                                         Class="transport-zone"/>

                    <VolumeZone Volume="@Volume" VolumeChanged="@OnVolumeChange"/>
@@ -9,6 +9,7 @@ namespace DeepDrftPublic.Client.Controls.AudioPlayerBar;
 public partial class AudioPlayerBar : ComponentBase, IAsyncDisposable
 {
    [CascadingParameter] public IStreamingPlayerService? PlayerService { get; set; }
+    [CascadingParameter] public IQueueService? QueueService { get; set; }
    [Parameter] public bool Fixed { get; set; } = false;

    [Parameter] public EventCallback<bool> OnMinimized { get; set; }
@@ -19,6 +20,7 @@ public partial class AudioPlayerBar : ComponentBase, IAsyncDisposable
    private bool _isSeeking = false;
    private double _seekPosition = 0;
    private IStreamingPlayerService? _subscribedService;
+    private IQueueService? _subscribedQueue;

    // Spacer-height bridge: the expanded dock is position:fixed, so MainLayout's
    // spacer reserves its space. We mirror this element's live height into a CSS
@@ -48,6 +50,11 @@ public partial class AudioPlayerBar : ComponentBase, IAsyncDisposable
    private double LoadProgress => PlayerService?.LoadProgress ?? 0;
    private string? ErrorMessage => PlayerService?.ErrorMessage;

+    // Skip affordances reflect live queue state. With no queue (null) or an empty queue both are
+    // false, so the buttons sit disabled and the bar behaves exactly as it did before the queue.
+    private bool HasNext => QueueService?.HasNext ?? false;
+    private bool HasPrevious => QueueService?.HasPrevious ?? false;
+
    /// <summary>
    /// Display time - shows seek position while dragging, otherwise current playback time.
    /// </summary>
@@ -76,10 +83,35 @@ public partial class AudioPlayerBar : ComponentBase, IAsyncDisposable
            PlayerService.StateChanged += OnPlayerStateChanged;
            _subscribedService = PlayerService;
        }
+
+        // The queue cascade is also IsFixed, so re-render the skip affordances off its own
+        // change signal — same posture as the player StateChanged subscription above.
+        if (QueueService != null && !ReferenceEquals(QueueService, _subscribedQueue))
+        {
+            if (_subscribedQueue != null)
+                _subscribedQueue.QueueChanged -= OnQueueChanged;
+
+            QueueService.QueueChanged += OnQueueChanged;
+            _subscribedQueue = QueueService;
+        }
    }

    private void OnPlayerStateChanged() => InvokeAsync(StateHasChanged);

+    private void OnQueueChanged() => InvokeAsync(StateHasChanged);
+
+    private async Task SkipNext()
+    {
+        if (QueueService == null) return;
+        await QueueService.Next();
+    }
+
+    private async Task SkipPrevious()
+    {
+        if (QueueService == null) return;
+        await QueueService.Previous();
+    }
+
    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        // Only the docked, expanded shape needs a spacer: the Fixed embed is
@@ -2,12 +2,25 @@
@using DeepDrftPublic.Client.Controls

 <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="2">
+    @if (!Fixed)
+    {
+        <MudIconButton Icon="@Icons.Material.Filled.SkipPrevious"
+                       Color="Color.Primary"
+                       Size="Size.Large"
+                       OnClick="@SkipPrevious"
+                       Disabled="!HasPrevious"/>
+    }
    <PlayStateIcon Size="Size.Large"
                   Color="Color.Primary"
                   Disabled="!CanPlay"
                   OnToggle="@TogglePlayPause"/>
    @if (!Fixed)
    {
+        <MudIconButton Icon="@Icons.Material.Filled.SkipNext"
+                       Color="Color.Primary"
+                       Size="Size.Large"
+                       OnClick="@SkipNext"
+                       Disabled="!HasNext"/>
        <MudIconButton Icon="@Icons.Material.Filled.Stop"
                       Color="Color.Primary"
                       Size="Size.Large"
@@ -16,4 +16,13 @@ public partial class PlayerControls : ComponentBase
    [Parameter] public bool Fixed { get; set; } = false;
    [Parameter] public required EventCallback TogglePlayPause { get; set; }
    [Parameter] public required EventCallback Stop { get; set; }
+
+    /// <summary>Whether the queue has a track to skip forward to. Drives the skip-next affordance.</summary>
+    [Parameter] public bool HasNext { get; set; }
+
+    /// <summary>Whether the queue has a track to step back to. Drives the skip-previous affordance.</summary>
+    [Parameter] public bool HasPrevious { get; set; }
+
+    [Parameter] public EventCallback SkipNext { get; set; }
+    [Parameter] public EventCallback SkipPrevious { get; set; }
 }
@@ -6,7 +6,11 @@
                        CanPlay="CanPlay"
                        Fixed="Fixed"
                        TogglePlayPause="TogglePlayPause"
-                        Stop="Stop"/>
+                        Stop="Stop"
+                        HasNext="HasNext"
+                        HasPrevious="HasPrevious"
+                        SkipNext="SkipNext"
+                        SkipPrevious="SkipPrevious"/>
        @if (IsLoading && !IsStreaming)
        {
            <MudProgressCircular Color="Color.Tertiary"
@@ -14,5 +14,9 @@ public partial class PlayerTransportZone : ComponentBase
    [Parameter] public bool Fixed { get; set; } = false;
    [Parameter] public EventCallback TogglePlayPause { get; set; }
    [Parameter] public EventCallback Stop { get; set; }
+    [Parameter] public bool HasNext { get; set; }
+    [Parameter] public bool HasPrevious { get; set; }
+    [Parameter] public EventCallback SkipNext { get; set; }
+    [Parameter] public EventCallback SkipPrevious { get; set; }
    [Parameter] public string? Class { get; set; }
 }
@@ -3,5 +3,7 @@
   If instance swapping at runtime is ever needed, change IsFixed to false (adds subscription
   overhead on every parent re-render, but allows children to see the new reference). *@
 <CascadingValue Value="@(_audioPlayerService)" IsFixed="true">
-    @ChildContent
+    <CascadingValue Value="@(_queueService)" IsFixed="true">
+        @ChildContent
+    </CascadingValue>
 </CascadingValue>
@@ -12,6 +12,7 @@ public partial class AudioPlayerProvider : ComponentBase, IAsyncDisposable
    [Inject] public required ILogger<StreamingAudioPlayerService> Logger { get; set; }

    private IStreamingPlayerService? _audioPlayerService;
+    private QueueService? _queueService;

    [Parameter] public RenderFragment? ChildContent { get; set; }

@@ -29,6 +30,13 @@ public partial class AudioPlayerProvider : ComponentBase, IAsyncDisposable
        // Children must not wrap or replace this callback.
        _audioPlayerService.OnStateChanged = new EventCallback(this, () => InvokeAsync(StateHasChanged));
        // OnTrackSelected will be set by individual child components that need it
+
+        // The queue orchestrates above the single-slot player. The player is not DI-registered
+        // (constructed here), so the queue binds to it via Attach rather than constructor injection —
+        // no construction cycle, no IServiceProvider. Cascaded alongside the player so the bar and a
+        // future up-next panel both read it.
+        _queueService = new QueueService();
+        _queueService.Attach(_audioPlayerService);
    }

    /// <summary>
@@ -38,6 +46,11 @@ public partial class AudioPlayerProvider : ComponentBase, IAsyncDisposable
    /// </summary>
    public async ValueTask DisposeAsync()
    {
+        // Dispose the queue first so it unsubscribes from the player's TrackEnded before the
+        // player tears down.
+        _queueService?.Dispose();
+        _queueService = null;
+
        if (_audioPlayerService is IAsyncDisposable disposable)
        {
            await disposable.DisposeAsync();
@@ -43,6 +43,9 @@ public abstract class AudioPlayerService : IPlayerService, IAsyncDisposable
    /// <inheritdoc />
    public event Action? StateChanged;

+    /// <inheritdoc />
+    public event Action? TrackEnded;
+
    protected AudioPlayerService(AudioInteropService audioInterop, TrackMediaClient trackMediaClient)
    {
        _audioInterop = audioInterop;
@@ -268,6 +271,12 @@ public abstract class AudioPlayerService : IPlayerService, IAsyncDisposable
        CurrentTime = 0;
        Duration = null;
        await NotifyStateChanged();
+
+        // Fire AFTER the state notification so any queue orchestrator that advances on this
+        // signal selects the next track against a fully-settled idle state. Raised only on
+        // organic end-of-stream — stop/unload/track-switch go through ResetToIdle, which does
+        // not raise this — so a subscriber can treat it unambiguously as "advance the queue."
+        TrackEnded?.Invoke();
    }


@@ -40,6 +40,15 @@ public interface IPlayerService
    /// <see cref="OnStateChanged"/> (throttled to ~10/s during streaming).
    /// </summary>
    event Action? StateChanged;
+
+    /// <summary>
+    /// Raised once when the current track reaches its natural end of playback (the JS
+    /// end-of-stream callback), distinct from a stop/unload/track-switch. This is the single
+    /// hook the play-queue subscribes to in order to auto-advance to the next track. It does
+    /// NOT fire when playback is stopped, the track is switched, or the player is unloaded —
+    /// only on organic completion — so an orchestrator can treat it as "advance the queue."
+    /// </summary>
+    event Action? TrackEnded;
    
    // Control methods
    Task InitializeAsync();
@@ -0,0 +1,80 @@
+using DeepDrftModels.DTOs;
+
+namespace DeepDrftPublic.Client.Services;
+
+/// <summary>
+/// Orchestrates ordered playback ("what plays next") <em>above</em> the single-slot
+/// <see cref="IStreamingPlayerService"/>. The player stays a single-track device; the queue owns the
+/// track list, the current position, skip-forward/back, and auto-advance on natural track end. It
+/// drives playback solely through the player's existing <see cref="IStreamingPlayerService.SelectTrackStreaming"/>
+/// — it adds no new playback semantics.
+///
+/// <para>
+/// Extension posture (open/closed): future shuffle, repeat modes, reordering, and persistence are
+/// expected. They are additive — a shuffle/repeat strategy slots in behind <see cref="Next"/>/
+/// <see cref="Previous"/> as the "which index is next" decision; reordering mutates <see cref="Items"/>
+/// and re-emits <see cref="QueueChanged"/>; persistence snapshots/restores <see cref="Items"/> +
+/// <see cref="CurrentIndex"/>. None of those require changing this interface's existing members, only
+/// adding new ones — so consumers written against today's surface keep working.
+/// </para>
+///
+/// <para>
+/// With an empty queue (<see cref="CurrentIndex"/> == -1) the queue is dormant: it drives nothing and
+/// auto-advances nothing, so direct single-track play through the player behaves exactly as it did
+/// before the queue existed.
+/// </para>
+/// </summary>
+public interface IQueueService
+{
+    /// <summary>The ordered tracks currently queued. Empty when nothing is enqueued.</summary>
+    IReadOnlyList<TrackDto> Items { get; }
+
+    /// <summary>
+    /// Index into <see cref="Items"/> of the track the queue considers current, or -1 when the
+    /// queue is empty. Always a valid index into <see cref="Items"/> when non-negative.
+    /// </summary>
+    int CurrentIndex { get; }
+
+    /// <summary>The current track, or null when the queue is empty.</summary>
+    TrackDto? Current { get; }
+
+    /// <summary>True when there is a track after <see cref="CurrentIndex"/> to advance to.</summary>
+    bool HasNext { get; }
+
+    /// <summary>True when there is a track before <see cref="CurrentIndex"/> to step back to.</summary>
+    bool HasPrevious { get; }
+
+    /// <summary>
+    /// Raised whenever the queue's contents or current position change. The player bar subscribes
+    /// to re-render its skip-forward/back affordances. Fires on enqueue, advance, step-back, and clear.
+    /// </summary>
+    event Action? QueueChanged;
+
+    /// <summary>
+    /// Replaces the queue with <paramref name="tracks"/> (in the order given) and begins streaming
+    /// the track at <paramref name="startIndex"/>. This is the "play album" entry point the Cuts
+    /// detail page consumes: pass the release's tracks in ordinal order. A header Play uses
+    /// <c>startIndex: 0</c>; a mid-album row play passes that row's index so the queue continues to
+    /// the end from there. No-op when <paramref name="tracks"/> is empty.
+    /// </summary>
+    Task PlayRelease(IEnumerable<TrackDto> tracks, int startIndex = 0);
+
+    /// <summary>Appends a track to the end of the queue without changing what is currently playing.</summary>
+    void Enqueue(TrackDto track);
+
+    /// <summary>Appends tracks to the end of the queue without changing what is currently playing.</summary>
+    void EnqueueRange(IEnumerable<TrackDto> tracks);
+
+    /// <summary>
+    /// Advances to the next track and streams it. No-op when <see cref="HasNext"/> is false.
+    /// </summary>
+    Task Next();
+
+    /// <summary>
+    /// Steps back to the previous track and streams it. No-op when <see cref="HasPrevious"/> is false.
+    /// </summary>
+    Task Previous();
+
+    /// <summary>Empties the queue and resets the position. Does not stop the player.</summary>
+    void Clear();
+}
@@ -0,0 +1,136 @@
+using DeepDrftModels.DTOs;
+
+namespace DeepDrftPublic.Client.Services;
+
+/// <summary>
+/// Default <see cref="IQueueService"/>: a single-slot orchestrator over an
+/// <see cref="IStreamingPlayerService"/>. Holds the ordered list and current index as pure state,
+/// drives playback through the player's existing <see cref="IStreamingPlayerService.SelectTrackStreaming"/>,
+/// and auto-advances on the player's <see cref="IPlayerService.TrackEnded"/> signal.
+///
+/// <para>
+/// The player instance is not DI-registered — <c>AudioPlayerProvider</c> constructs and cascades it.
+/// So the queue is bound to the player via <see cref="Attach"/> (called once by the provider after it
+/// creates the player) rather than constructor injection. This keeps the player single-slot, avoids a
+/// construction cycle between provider/player/queue, and needs no <c>IServiceProvider</c>. The queue's
+/// own constructor stays parameterless, so the queue logic is unit-testable against a fake player with
+/// no container.
+/// </para>
+/// </summary>
+public sealed class QueueService : IQueueService, IDisposable
+{
+    private readonly List<TrackDto> _items = new();
+    private IStreamingPlayerService? _player;
+
+    public IReadOnlyList<TrackDto> Items => _items;
+
+    public int CurrentIndex { get; private set; } = -1;
+
+    public TrackDto? Current =>
+        CurrentIndex >= 0 && CurrentIndex < _items.Count ? _items[CurrentIndex] : null;
+
+    public bool HasNext => CurrentIndex >= 0 && CurrentIndex < _items.Count - 1;
+
+    public bool HasPrevious => CurrentIndex > 0;
+
+    public event Action? QueueChanged;
+
+    /// <summary>
+    /// Binds the queue to the player instance the provider owns, and subscribes to its track-ended
+    /// signal so the queue auto-advances. Idempotent and re-bindable: re-attaching detaches the prior
+    /// player first, so the queue never holds a stale subscription after a player swap. Owned by the
+    /// provider's lifecycle; <see cref="Dispose"/> unsubscribes.
+    /// </summary>
+    public void Attach(IStreamingPlayerService player)
+    {
+        if (ReferenceEquals(_player, player)) return;
+
+        if (_player != null)
+            _player.TrackEnded -= OnTrackEnded;
+
+        _player = player;
+        _player.TrackEnded += OnTrackEnded;
+    }
+
+    public async Task PlayRelease(IEnumerable<TrackDto> tracks, int startIndex = 0)
+    {
+        var list = tracks as IReadOnlyList<TrackDto> ?? tracks.ToList();
+        if (list.Count == 0) return;
+
+        var start = Math.Clamp(startIndex, 0, list.Count - 1);
+
+        _items.Clear();
+        _items.AddRange(list);
+        CurrentIndex = start;
+        QueueChanged?.Invoke();
+
+        await PlayCurrent();
+    }
+
+    public void Enqueue(TrackDto track)
+    {
+        _items.Add(track);
+        QueueChanged?.Invoke();
+    }
+
+    public void EnqueueRange(IEnumerable<TrackDto> tracks)
+    {
+        var before = _items.Count;
+        _items.AddRange(tracks);
+        if (_items.Count != before)
+            QueueChanged?.Invoke();
+    }
+
+    public async Task Next()
+    {
+        if (!HasNext) return;
+        CurrentIndex++;
+        QueueChanged?.Invoke();
+        await PlayCurrent();
+    }
+
+    public async Task Previous()
+    {
+        if (!HasPrevious) return;
+        CurrentIndex--;
+        QueueChanged?.Invoke();
+        await PlayCurrent();
+    }
+
+    public void Clear()
+    {
+        if (_items.Count == 0 && CurrentIndex == -1) return;
+        _items.Clear();
+        CurrentIndex = -1;
+        QueueChanged?.Invoke();
+    }
+
+    // Advance on organic end-of-stream only. TrackEnded is not raised by stop/unload/track-switch,
+    // so a manual stop or a fresh single-track selection elsewhere never spuriously advances the
+    // queue. When the queue is past its last track, end-of-stream simply stops — nothing to advance.
+    private void OnTrackEnded()
+    {
+        if (!HasNext) return;
+        // Fire-and-forget is deliberate: TrackEnded is a synchronous event invoked from the player's
+        // end-of-playback callback continuation; we must not block it. Advancing kicks off the next
+        // stream, whose own failures surface through the player's ErrorMessage/state — the queue does
+        // not own playback error handling.
+        _ = Next();
+    }
+
+    private async Task PlayCurrent()
+    {
+        var track = Current;
+        if (track is null || _player is null) return;
+        await _player.SelectTrackStreaming(track);
+    }
+
+    public void Dispose()
+    {
+        if (_player != null)
+        {
+            _player.TrackEnded -= OnTrackEnded;
+            _player = null;
+        }
+    }
+}