harmonia/Harmonia.UI/ViewModels/PlaylistViewModel.cs

using Harmonia.Core.Player;
using Harmonia.Core.Playlists;
using System;
using System.Collections.ObjectModel;
using System.Threading.Tasks;
using System.Threading;
using Avalonia.Media.Imaging;
using System.Collections.Concurrent;
using Harmonia.UI.Caching;

namespace Harmonia.UI.ViewModels;

public class PlaylistViewModel : ViewModelBase
{
    private readonly IAudioPlayer _audioPlayer;
    private readonly IAudioBitmapCache _audioBitmapImageCache;
    private readonly ConcurrentDictionary<string, Bitmap> _bitmapDictionary = [];

    public PlaylistSong? PlayingSong => _audioPlayer.PlayingSong;

    private ObservableCollection<PlaylistSong> _playlistSongs = [];
    public ObservableCollection<PlaylistSong> PlaylistSongs
    {
        get
        {
            return _playlistSongs;
        }
        set
        {
            _playlistSongs = value;
            OnPropertyChanged();
        }
    }

    public PlaylistViewModel(IAudioPlayer audioPlayer, IAudioBitmapCache audioBitmapImageCache)
    {
        _audioPlayer = audioPlayer;
        _audioPlayer.PlaylistChanged += OnAudioPlayerPlaylistChanged;
        _audioPlayer.PlayingSongChanged += OnAudioPlayerPlayingSongChanged;

        _audioBitmapImageCache = audioBitmapImageCache;
    }

    private void OnAudioPlayerPlaylistChanged(object? sender, EventArgs e)
    {
        PlaylistSong[] playlistSongs = _audioPlayer.Playlist?.Songs.ToArray() ?? [];

        PlaylistSongs = [.. playlistSongs];
    }

    private void OnAudioPlayerPlayingSongChanged(object? sender, EventArgs e)
    {
        OnPropertyChanged(nameof(PlayingSong));
    }

    public void PlaySong(PlaylistSong playlistSong)
    {
        _audioPlayer.LoadAsync(playlistSong, PlaybackMode.LoadAndPlay);
    }

    public async Task<Bitmap?> GetBitmapAsync(PlaylistSong playlistSong, CancellationToken cancellationToken)
    {
        return await _audioBitmapImageCache.GetAsync(playlistSong.Song, cancellationToken);
    }
}