harmonia/Harmonia.Core/Playlists/PlaylistManager.cs

namespace Harmonia.Core.Playlists;

public class PlaylistManager : IPlaylistManager
{
    private readonly IPlaylistRepository playlistRepository;
    private readonly List<Playlist> _playlists = [];

    public IReadOnlyList<Playlist> Playlists => _playlists;

    private Playlist? _currentPlaylist;
    public Playlist? CurrentPlaylist
    {
        get
        {
            return _currentPlaylist;
        }
        set
        {
            _currentPlaylist = value;
            CurrentPlaylistChanged?.Invoke(this, new());
        }
    }

    public event EventHandler? CurrentPlaylistChanged;
    public event EventHandler<PlaylistAddedEventArgs>? PlaylistAdded;
    public event EventHandler<PlaylistRemovedEventArgs>? PlaylistRemoved;

    public PlaylistManager(IPlaylistRepository playlistRepository)
    {
        this.playlistRepository = playlistRepository;
    }

    public async Task InitializeAsync()
    {
        _playlists.AddRange(playlistRepository.Get());

        foreach (Playlist playlist in _playlists)
        {
            playlist.PlaylistUpdated += OnPlaylistUpdated;
        }

        CurrentPlaylist = _playlists.Count > 0 ? _playlists[0] : await AddPlaylistAsync();
    }

    public async Task<Playlist> AddPlaylistAsync()
    {
        Playlist playlist = new()
        {
            Name = "New Playlist"
        };

        playlist.PlaylistUpdated += OnPlaylistUpdated;
        _playlists.Add(playlist);

        await playlistRepository.SaveAsync(playlist);

        PlaylistAdded?.Invoke(this, new(playlist));

        return playlist;
    }

    public void RemovePlaylist(Playlist playlist)
    {
        playlist.PlaylistUpdated -= OnPlaylistUpdated;
        _playlists.Remove(playlist);

        playlistRepository.Delete(playlist);

        PlaylistRemoved?.Invoke(this, new(playlist));
    }

    public Playlist? GetPlaylist(PlaylistSong playlistSong)
    {
        return _playlists.FirstOrDefault(playlist => playlist.Songs.Any(song => song.UID == playlistSong.UID));
    }

    private async void OnPlaylistUpdated(object? sender, PlaylistUpdatedEventArgs e)
    {
        if (sender is not Playlist playlist)
            return;

        await playlistRepository.SaveAsync(playlist);
    }
}