using ytLive.Services.Audio;
using ytLive.Services.Encoder;

namespace ytLive.Services;

/// <summary>
/// TASK 21: decodes a local media file (any format ffmpeg handles) into
/// <see cref="VideoFrame"/>s for a MediaSource. This is the <see cref="IMediaFrameSource"/>
/// shape over the shared <see cref="VideoClipPipe"/> — the same pipe an alert clip uses
/// (TASK 47), so the two features cannot drift apart again in how they decode.
/// <para>Video AND the file's own soundtrack are decoded. The manager scales the audio by
/// the layer's level/mute and hands it to the mixer's desktop group.</para>
/// </summary>
public sealed class MediaVideoSource : IMediaFrameSource
{
    public event Action<VideoFrame>? FrameAvailable;
    public event Action<AudioSample>? AudioAvailable;
    public event Action? Completed;

    public string Key => _path;

    public bool Looping
    {
        get => _clip.Looping;
        set => _clip.Looping = value;
    }

    private readonly string _path;
    private readonly VideoClipPipe _clip;

    public MediaVideoSource(
        string path,
        int width,
        int height,
        IFfmpegLocator locator,
        Func<IDecodeProcess> processFactory,
        IFrameRateProbe? frameRateProbe = null,
        Func<TimeSpan, CancellationToken, Task>? delay = null)
    {
        _path = path;
        _clip = new VideoClipPipe(
            path, width, height, locator, processFactory, frameRateProbe, delay, audio: true);
        _clip.FrameAvailable += frame => FrameAvailable?.Invoke(frame);
        _clip.AudioAvailable += sample => AudioAvailable?.Invoke(sample);
        _clip.Completed += () => Completed?.Invoke();
    }

    public Task StartAsync(CancellationToken cancellationToken = default) => _clip.StartAsync(cancellationToken);

    public Task StopAsync() => _clip.StopAsync();

    public void Dispose() => _clip.Dispose();
}