// Copyright (c) Arlo Godfrey. All Rights Reserved.
// Licensed under the GNU Lesser General Public License, Version 3.0 with additional terms.
// See the LICENSE, LICENSE.LESSER and LICENSE.ADDITIONAL files in the project root for more information.

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using CommunityToolkit.Diagnostics;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using OwlCore;
using OwlCore.Events;
using OwlCore.Extensions;
using StrixMusic.Sdk.AdapterModels;
using StrixMusic.Sdk.AppModels;
using StrixMusic.Sdk.BaseModels;
using StrixMusic.Sdk.CoreModels;
using StrixMusic.Sdk.Extensions;
using StrixMusic.Sdk.MediaPlayback;
using StrixMusic.Sdk.ViewModels.Helpers;

namespace StrixMusic.Sdk.ViewModels
{
    /// <summary>
    /// A ViewModel for <see cref="IArtist"/>.
    /// </summary>
    public sealed class ArtistViewModel : ObservableObject, IArtist, ISdkViewModel, IAlbumCollectionViewModel, ITrackCollectionViewModel, IImageCollectionViewModel, IGenreCollectionViewModel, IUrlCollectionViewModel
    {
        private readonly IArtist _artist;

        private readonly SemaphoreSlim _populateTracksMutex = new(1, 1);
        private readonly SemaphoreSlim _populateAlbumsMutex = new(1, 1);
        private readonly SemaphoreSlim _populateImagesMutex = new(1, 1);
        private readonly SemaphoreSlim _populateGenresMutex = new(1, 1);
        private readonly SemaphoreSlim _populateUrlsMutex = new(1, 1);
        private readonly SynchronizationContext _syncContext;

        /// <summary>
        /// Initializes a new instance of the <see cref="ArtistViewModel"/> class.
        /// </summary>
        /// <param name="artist">The <see cref="IArtist"/> to wrap.</param>
        public ArtistViewModel(IArtist artist)
        {
            _syncContext = SynchronizationContext.Current;

            _artist = artist;

            if (_artist.RelatedItems != null)
                RelatedItems = new PlayableCollectionGroupViewModel(_artist.RelatedItems);

            UnsortedTracks = new ObservableCollection<TrackViewModel>();
            UnsortedAlbums = new ObservableCollection<IAlbumCollectionItem>();
            Tracks = new ObservableCollection<TrackViewModel>();
            Albums = new ObservableCollection<IAlbumCollectionItem>();
            Images = new ObservableCollection<IImage>();
            Genres = new ObservableCollection<IGenre>();
            Urls = new ObservableCollection<IUrl>();

            PlayTrackCollectionAsyncCommand = new AsyncRelayCommand(PlayTrackCollectionAsync);
            PauseTrackCollectionAsyncCommand = new AsyncRelayCommand(PauseTrackCollectionAsync);
            PlayAlbumCollectionAsyncCommand = new AsyncRelayCommand(PlayAlbumCollectionAsync);
            PauseAlbumCollectionAsyncCommand = new AsyncRelayCommand(PauseAlbumCollectionAsync);

            PlayTrackAsyncCommand = new AsyncRelayCommand<ITrack>((x, y) => _artist.PlayTrackCollectionAsync(x ?? ThrowHelper.ThrowArgumentNullException<ITrack>(nameof(x)), y));
            PlayAlbumAsyncCommand = new AsyncRelayCommand<IAlbumCollectionItem>((x, y) => _artist.PlayAlbumCollectionAsync(x ?? ThrowHelper.ThrowArgumentNullException<IAlbumCollectionItem>(nameof(x)), y));

            ChangeNameAsyncCommand = new AsyncRelayCommand<string>(ChangeNameInternalAsync);
            ChangeDescriptionAsyncCommand = new AsyncRelayCommand<string?>(ChangeDescriptionAsync);
            ChangeDurationAsyncCommand = new AsyncRelayCommand<TimeSpan>(ChangeDurationAsync);

            PopulateMoreAlbumsCommand = new AsyncRelayCommand<int>(PopulateMoreAlbumsAsync);
            PopulateMoreTracksCommand = new AsyncRelayCommand<int>(PopulateMoreTracksAsync);
            PopulateMoreImagesCommand = new AsyncRelayCommand<int>(PopulateMoreImagesAsync);
            PopulateMoreGenresCommand = new AsyncRelayCommand<int>(PopulateMoreGenresAsync);
            PopulateMoreUrlsCommand = new AsyncRelayCommand<int>(PopulateMoreUrlsAsync);

            InitAlbumCollectionAsyncCommand = new AsyncRelayCommand(InitAlbumCollectionAsync);
            InitGenreCollectionAsyncCommand = new AsyncRelayCommand(InitGenreCollectionAsync);
            InitImageCollectionAsyncCommand = new AsyncRelayCommand(InitImageCollectionAsync);
            InitTrackCollectionAsyncCommand = new AsyncRelayCommand(InitTrackCollectionAsync);

            ChangeAlbumCollectionSortingTypeCommand = new RelayCommand<AlbumSortingType>(x => SortAlbumCollection(x, CurrentAlbumSortingDirection));
            ChangeAlbumCollectionSortingDirectionCommand = new RelayCommand<SortDirection>(x => SortAlbumCollection(CurrentAlbumSortingType, x));
            ChangeTrackCollectionSortingTypeCommand = new RelayCommand<TrackSortingType>(x => SortTrackCollection(x, CurrentTracksSortingDirection));
            ChangeTrackCollectionSortingDirectionCommand = new RelayCommand<SortDirection>(x => SortTrackCollection(CurrentTracksSortingType, x));

            AttachEvents();
        }

        private void AttachEvents()
        {
            PlaybackStateChanged += ArtistPlaybackStateChanged;
            DescriptionChanged += ArtistDescriptionChanged;
            NameChanged += ArtistNameChanged;
            LastPlayedChanged += OnLastPlayedChanged;
            DownloadInfoChanged += OnDownloadInfoChanged;

            IsPlayTrackCollectionAsyncAvailableChanged += OnIsPlayTrackCollectionAsyncAvailableChanged;
            IsPauseTrackCollectionAsyncAvailableChanged += OnIsPauseTrackCollectionAsyncAvailableChanged;
            IsPlayAlbumCollectionAsyncAvailableChanged += OnIsPlayAlbumCollectionAsyncAvailableChanged;
            IsPauseAlbumCollectionAsyncAvailableChanged += OnIsPauseAlbumCollectionAsyncAvailableChanged;

            IsChangeNameAsyncAvailableChanged += OnIsChangeNameAsyncAvailableChanged;
            IsChangeDurationAsyncAvailableChanged += OnIsChangeDurationAsyncAvailableChanged;
            IsChangeDescriptionAsyncAvailableChanged += OnIsChangeDescriptionAsyncAvailableChanged;

            AlbumItemsCountChanged += Artist_AlbumItemsCountChanged;
            TracksCountChanged += ArtistOnTrackItemsCountChanged;
            ImagesCountChanged += ArtistViewModel_ImagesCountChanged;
            GenresCountChanged += ArtistViewModel_GenresCountChanged;
            UrlsCountChanged += ArtistViewModel_UrlsCountChanged;

            AlbumItemsChanged += ArtistViewModel_AlbumItemsChanged;
            TracksChanged += ArtistViewModel_TrackItemsChanged;
            ImagesChanged += ArtistViewModel_ImagesChanged;
            GenresChanged += ArtistViewModel_GenresChanged;
            ImagesChanged += ArtistViewModel_ImagesChanged;
        }

        private void DetachEvents()
        {
            PlaybackStateChanged -= ArtistPlaybackStateChanged;
            DescriptionChanged -= ArtistDescriptionChanged;
            NameChanged -= ArtistNameChanged;
            LastPlayedChanged -= OnLastPlayedChanged;
            DownloadInfoChanged -= OnDownloadInfoChanged;

            IsPlayTrackCollectionAsyncAvailableChanged -= OnIsPlayTrackCollectionAsyncAvailableChanged;
            IsPauseTrackCollectionAsyncAvailableChanged -= OnIsPauseTrackCollectionAsyncAvailableChanged;
            IsPlayAlbumCollectionAsyncAvailableChanged -= OnIsPlayAlbumCollectionAsyncAvailableChanged;
            IsPauseAlbumCollectionAsyncAvailableChanged -= OnIsPauseAlbumCollectionAsyncAvailableChanged;

            IsChangeNameAsyncAvailableChanged -= OnIsChangeNameAsyncAvailableChanged;
            IsChangeDurationAsyncAvailableChanged -= OnIsChangeDurationAsyncAvailableChanged;
            IsChangeDescriptionAsyncAvailableChanged -= OnIsChangeDescriptionAsyncAvailableChanged;

            AlbumItemsCountChanged -= Artist_AlbumItemsCountChanged;
            TracksCountChanged -= ArtistOnTrackItemsCountChanged;
            ImagesCountChanged -= ArtistViewModel_ImagesCountChanged;
            GenresCountChanged -= ArtistViewModel_GenresCountChanged;

            AlbumItemsChanged -= ArtistViewModel_AlbumItemsChanged;
            TracksChanged -= ArtistViewModel_TrackItemsChanged;
            ImagesChanged -= ArtistViewModel_ImagesChanged;
            GenresChanged -= ArtistViewModel_GenresChanged;
        }

        /// <inheritdoc/>
        public event EventHandler? SourcesChanged
        {
            add => _artist.SourcesChanged += value;
            remove => _artist.SourcesChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<TimeSpan>? DurationChanged
        {
            add => _artist.DurationChanged += value;
            remove => _artist.DurationChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<DateTime?>? LastPlayedChanged
        {
            add => _artist.LastPlayedChanged += value;
            remove => _artist.LastPlayedChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<bool>? IsPlayTrackCollectionAsyncAvailableChanged
        {
            add => _artist.IsPlayTrackCollectionAsyncAvailableChanged += value;
            remove => _artist.IsPlayTrackCollectionAsyncAvailableChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<bool>? IsPauseTrackCollectionAsyncAvailableChanged
        {
            add => _artist.IsPauseTrackCollectionAsyncAvailableChanged += value;
            remove => _artist.IsPauseTrackCollectionAsyncAvailableChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<bool>? IsPlayAlbumCollectionAsyncAvailableChanged
        {
            add => _artist.IsPlayAlbumCollectionAsyncAvailableChanged += value;
            remove => _artist.IsPlayAlbumCollectionAsyncAvailableChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<bool>? IsPauseAlbumCollectionAsyncAvailableChanged
        {
            add => _artist.IsPauseAlbumCollectionAsyncAvailableChanged += value;
            remove => _artist.IsPauseAlbumCollectionAsyncAvailableChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<bool>? IsChangeNameAsyncAvailableChanged
        {
            add => _artist.IsChangeNameAsyncAvailableChanged += value;
            remove => _artist.IsChangeNameAsyncAvailableChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<bool>? IsChangeDescriptionAsyncAvailableChanged
        {
            add => _artist.IsChangeDescriptionAsyncAvailableChanged += value;
            remove => _artist.IsChangeDescriptionAsyncAvailableChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<bool>? IsChangeDurationAsyncAvailableChanged
        {
            add => _artist.IsChangeDurationAsyncAvailableChanged += value;
            remove => _artist.IsChangeDurationAsyncAvailableChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<PlaybackState>? PlaybackStateChanged
        {
            add => _artist.PlaybackStateChanged += value;
            remove => _artist.PlaybackStateChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<DownloadInfo>? DownloadInfoChanged
        {
            add => _artist.DownloadInfoChanged += value;
            remove => _artist.DownloadInfoChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<string>? NameChanged
        {
            add => _artist.NameChanged += value;
            remove => _artist.NameChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<string?>? DescriptionChanged
        {
            add => _artist.DescriptionChanged += value;
            remove => _artist.DescriptionChanged -= value;
        }

        /// <inheritdoc />
        public event CollectionChangedEventHandler<IAlbumCollectionItem>? AlbumItemsChanged
        {
            add => _artist.AlbumItemsChanged += value;
            remove => _artist.AlbumItemsChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<int>? AlbumItemsCountChanged
        {
            add => _artist.AlbumItemsCountChanged += value;
            remove => _artist.AlbumItemsCountChanged -= value;
        }

        /// <inheritdoc />
        public event CollectionChangedEventHandler<ITrack>? TracksChanged
        {
            add => _artist.TracksChanged += value;
            remove => _artist.TracksChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<int>? TracksCountChanged
        {
            add => _artist.TracksCountChanged += value;
            remove => _artist.TracksCountChanged -= value;
        }

        /// <inheritdoc />
        public event EventHandler<int>? ImagesCountChanged
        {
            add => _artist.ImagesCountChanged += value;
            remove => _artist.ImagesCountChanged -= value;
        }

        /// <inheritdoc />
        public event CollectionChangedEventHandler<IImage>? ImagesChanged
        {
            add => _artist.ImagesChanged += value;
            remove => _artist.ImagesChanged -= value;
        }

        /// <inheritdoc/>
        public event CollectionChangedEventHandler<IGenre>? GenresChanged
        {
            add => _artist.GenresChanged += value;
            remove => _artist.GenresChanged -= value;
        }

        /// <inheritdoc/>
        public event EventHandler<int>? GenresCountChanged
        {
            add => _artist.GenresCountChanged += value;
            remove => _artist.GenresCountChanged -= value;
        }

        /// <inheritdoc />
        public event CollectionChangedEventHandler<IUrl>? UrlsChanged
        {
            add => _artist.UrlsChanged += value;
            remove => _artist.UrlsChanged -= value;
        }

        /// <inheritdoc/>
        public event EventHandler<int>? UrlsCountChanged
        {
            add => _artist.UrlsCountChanged += value;
            remove => _artist.UrlsCountChanged -= value;
        }

        private void ArtistNameChanged(object sender, string e) => _syncContext.Post(_ => OnPropertyChanged(nameof(Name)), null);

        private void ArtistDescriptionChanged(object sender, string? e) => _syncContext.Post(_ => OnPropertyChanged(nameof(Description)), null);

        private void ArtistPlaybackStateChanged(object sender, PlaybackState e) => _syncContext.Post(_ => OnPropertyChanged(nameof(PlaybackState)), null);

        private void OnDownloadInfoChanged(object sender, DownloadInfo e) => _syncContext.Post(_ => OnPropertyChanged(nameof(DownloadInfo)), null);

        private void ArtistOnTrackItemsCountChanged(object sender, int e) => _syncContext.Post(_ => OnPropertyChanged(nameof(TotalTrackCount)), null);

        private void Artist_AlbumItemsCountChanged(object sender, int e) => _syncContext.Post(_ => OnPropertyChanged(nameof(TotalAlbumItemsCount)), null);

        private void ArtistViewModel_ImagesCountChanged(object sender, int e) => _syncContext.Post(_ => OnPropertyChanged(nameof(TotalImageCount)), null);

        private void ArtistViewModel_UrlsCountChanged(object sender, int e) => _syncContext.Post(_ => OnPropertyChanged(nameof(TotalUrlCount)), null);

        private void ArtistViewModel_GenresCountChanged(object sender, int e) => _syncContext.Post(_ => OnPropertyChanged(nameof(TotalGenreCount)), null);

        private void OnLastPlayedChanged(object sender, DateTime? e) => _syncContext.Post(_ => OnPropertyChanged(nameof(LastPlayed)), null);

        private void OnIsChangeDescriptionAsyncAvailableChanged(object sender, bool e) => _syncContext.Post(_ => OnPropertyChanged(nameof(IsChangeDescriptionAsyncAvailable)), null);

        private void OnIsChangeDurationAsyncAvailableChanged(object sender, bool e) => _syncContext.Post(_ => OnPropertyChanged(nameof(IsChangeDurationAsyncAvailable)), null);

        private void OnIsChangeNameAsyncAvailableChanged(object sender, bool e) => _syncContext.Post(_ => OnPropertyChanged(nameof(IsChangeNameAsyncAvailable)), null);

        private void OnIsPauseTrackCollectionAsyncAvailableChanged(object sender, bool e) => _syncContext.Post(_ => OnPropertyChanged(nameof(IsPauseTrackCollectionAsyncAvailable)), null);

        private void OnIsPlayTrackCollectionAsyncAvailableChanged(object sender, bool e) => _syncContext.Post(_ => OnPropertyChanged(nameof(IsPlayTrackCollectionAsyncAvailable)), null);

        private void OnIsPauseAlbumCollectionAsyncAvailableChanged(object sender, bool e) => _syncContext.Post(_ => OnPropertyChanged(nameof(IsPauseAlbumCollectionAsyncAvailable)), null);

        private void OnIsPlayAlbumCollectionAsyncAvailableChanged(object sender, bool e) => _syncContext.Post(_ => OnPropertyChanged(nameof(IsPlayAlbumCollectionAsyncAvailable)), null);

        private void ArtistViewModel_ImagesChanged(object sender, IReadOnlyList<CollectionChangedItem<IImage>> addedItems, IReadOnlyList<CollectionChangedItem<IImage>> removedItems) => _syncContext.Post(_ =>
        {
            Images.ChangeCollection(addedItems, removedItems);
        }, null);

        private void ArtistViewModel_GenresChanged(object sender, IReadOnlyList<CollectionChangedItem<IGenre>> addedItems, IReadOnlyList<CollectionChangedItem<IGenre>> removedItems) => _syncContext.Post(_ =>
        {
            Genres.ChangeCollection(addedItems, removedItems);
        }, null);

        private void ArtistViewModel_TrackItemsChanged(object sender, IReadOnlyList<CollectionChangedItem<ITrack>> addedItems, IReadOnlyList<CollectionChangedItem<ITrack>> removedItems) => _syncContext.Post(_ =>
        {
            if (CurrentTracksSortingType == TrackSortingType.Unsorted)
            {
                Tracks.ChangeCollection(addedItems, removedItems, x => new TrackViewModel(x.Data));
            }
            else
            {
                // Make sure both ordered and unordered tracks are updated. 
                UnsortedTracks.ChangeCollection(addedItems, removedItems, x => new TrackViewModel(x.Data));

                foreach (var item in UnsortedTracks)
                {
                    if (!Tracks.Contains(item))
                        Tracks.Add(item);
                }

                foreach (var item in Tracks.ToArray())
                {
                    if (!UnsortedTracks.Contains(item))
                        Tracks.Remove(item);
                }

                SortTrackCollection(CurrentTracksSortingType, CurrentTracksSortingDirection);
            }
        }, null);

        private void ArtistViewModel_AlbumItemsChanged(object sender, IReadOnlyList<CollectionChangedItem<IAlbumCollectionItem>> addedItems, IReadOnlyList<CollectionChangedItem<IAlbumCollectionItem>> removedItems) => _syncContext.Post(_ =>
        {
            if (CurrentAlbumSortingType == AlbumSortingType.Unsorted)
            {
                Albums.ChangeCollection(addedItems, removedItems, item => item.Data switch
                {
                    IAlbum album => new AlbumViewModel(album),
                    IAlbumCollection collection => new AlbumCollectionViewModel(collection),
                    _ => ThrowHelper.ThrowNotSupportedException<IAlbumCollectionItem>(
                        $"{item.Data.GetType()} not supported for adding to {GetType()}")
                });
            }
            else
            {
                // Make sure both ordered and unordered albums are updated. 
                UnsortedAlbums.ChangeCollection(addedItems, removedItems, item => item.Data switch
                {
                    IAlbum album => new AlbumViewModel(album),
                    IAlbumCollection collection => new AlbumCollectionViewModel(collection),
                    _ => ThrowHelper.ThrowNotSupportedException<IAlbumCollectionItem>(
                        $"{item.Data.GetType()} not supported for adding to {GetType()}")
                });

                foreach (var item in UnsortedAlbums)
                {
                    if (!Albums.Contains(item))
                        Albums.Add(item);
                }

                foreach (var item in Albums.ToArray())
                {
                    if (!UnsortedAlbums.Contains(item))
                        Albums.Remove(item);
                }

                SortAlbumCollection(CurrentAlbumSortingType, CurrentAlbumSortingDirection);
            }
        }, null);

        /// <summary>
        /// The sources that were merged to form this member.
        /// </summary>
        public IReadOnlyList<ICoreArtist> Sources => _artist.GetSources<ICoreArtist>();

        /// <inheritdoc />
        IReadOnlyList<ICoreArtist> IMerged<ICoreArtist>.Sources => Sources;

        /// <inheritdoc />
        IReadOnlyList<ICoreTrackCollection> IMerged<ICoreTrackCollection>.Sources => Sources;

        /// <inheritdoc />
        IReadOnlyList<ICoreAlbumCollection> IMerged<ICoreAlbumCollection>.Sources => Sources;

        /// <inheritdoc />
        IReadOnlyList<ICoreAlbumCollectionItem> IMerged<ICoreAlbumCollectionItem>.Sources => Sources;

        /// <inheritdoc />
        IReadOnlyList<ICoreArtistCollectionItem> IMerged<ICoreArtistCollectionItem>.Sources => Sources;

        /// <inheritdoc />
        IReadOnlyList<ICoreGenreCollection> IMerged<ICoreGenreCollection>.Sources => Sources;

        /// <inheritdoc />
        IReadOnlyList<ICoreImageCollection> IMerged<ICoreImageCollection>.Sources => Sources;

        /// <inheritdoc />
        IReadOnlyList<ICoreUrlCollection> IMerged<ICoreUrlCollection>.Sources => Sources;

        /// <inheritdoc />
        public string Id => _artist.Id;

        /// <inheritdoc cref="IPlayableBase.Duration" />
        public TimeSpan Duration => _artist.Duration;

        /// <inheritdoc />
        public DateTime? LastPlayed => _artist.LastPlayed;

        /// <inheritdoc />
        public DateTime? AddedAt => _artist.AddedAt;

        /// <inheritdoc />
        public bool IsInitialized { get; private set; }

        /// <inheritdoc />
        public IPlayableCollectionGroup? RelatedItems { get; }

        /// <inheritdoc />
        public TrackSortingType CurrentTracksSortingType { get; private set; }

        /// <inheritdoc />
        public SortDirection CurrentTracksSortingDirection { get; private set; }

        /// <inheritdoc />
        public AlbumSortingType CurrentAlbumSortingType { get; private set; }

        /// <inheritdoc />
        public SortDirection CurrentAlbumSortingDirection { get; private set; }

        /// <inheritdoc />
        public ObservableCollection<TrackViewModel> Tracks { get; set; }

        /// <inheritdoc />
        public ObservableCollection<TrackViewModel> UnsortedTracks { get; }

        /// <inheritdoc />
        public ObservableCollection<IAlbumCollectionItem> Albums { get; }

        ///<inheritdoc />
        public ObservableCollection<IAlbumCollectionItem> UnsortedAlbums { get; }

        /// <inheritdoc />
        public ObservableCollection<IImage> Images { get; }

        /// <inheritdoc />
        public ObservableCollection<IGenre> Genres { get; }

        /// <inheritdoc />
        public ObservableCollection<IUrl> Urls { get; }

        /// <inheritdoc />
        public string Name => _artist.Name;

        /// <inheritdoc />
        public int TotalAlbumItemsCount => _artist.TotalAlbumItemsCount;

        /// <inheritdoc />
        public int TotalTrackCount => _artist.TotalTrackCount;

        /// <inheritdoc />
        public int TotalImageCount => _artist.TotalImageCount;

        /// <inheritdoc />
        public int TotalGenreCount => _artist.TotalGenreCount;

        /// <inheritdoc />
        public int TotalUrlCount => _artist.TotalTrackCount;

        /// <inheritdoc />
        public string? Description => _artist.Description;

        /// <inheritdoc />
        public PlaybackState PlaybackState => _artist.PlaybackState;

        /// <inheritdoc />
        public DownloadInfo DownloadInfo => _artist.DownloadInfo;

        /// <inheritdoc />
        public bool IsPlayTrackCollectionAsyncAvailable => _artist.IsPlayTrackCollectionAsyncAvailable;

        /// <inheritdoc />
        public bool IsPauseTrackCollectionAsyncAvailable => _artist.IsPauseTrackCollectionAsyncAvailable;

        /// <inheritdoc />
        public bool IsPlayAlbumCollectionAsyncAvailable => _artist.IsPlayAlbumCollectionAsyncAvailable;

        /// <inheritdoc />
        public bool IsPauseAlbumCollectionAsyncAvailable => _artist.IsPauseAlbumCollectionAsyncAvailable;

        /// <inheritdoc />
        public bool IsChangeNameAsyncAvailable => _artist.IsChangeNameAsyncAvailable;

        /// <inheritdoc />
        public bool IsChangeDescriptionAsyncAvailable => _artist.IsChangeDescriptionAsyncAvailable;

        /// <inheritdoc />
        public bool IsChangeDurationAsyncAvailable => _artist.IsChangeDurationAsyncAvailable;

        /// <inheritdoc />
        public Task PlayTrackCollectionAsync(CancellationToken cancellationToken = default) => _artist.PlayTrackCollectionAsync(cancellationToken);

        /// <inheritdoc />
        public Task PlayAlbumCollectionAsync(CancellationToken cancellationToken = default) => _artist.PlayAlbumCollectionAsync(cancellationToken);

        /// <inheritdoc />
        public Task PauseTrackCollectionAsync(CancellationToken cancellationToken = default) => _artist.PauseTrackCollectionAsync(cancellationToken);

        /// <inheritdoc />
        public Task PauseAlbumCollectionAsync(CancellationToken cancellationToken = default) => _artist.PauseAlbumCollectionAsync(cancellationToken);

        /// <inheritdoc />
        public Task ChangeNameAsync(string name, CancellationToken cancellationToken = default) => ChangeNameInternalAsync(name, cancellationToken);

        /// <inheritdoc />
        public Task ChangeDescriptionAsync(string? description, CancellationToken cancellationToken = default) => _artist.ChangeDescriptionAsync(description, cancellationToken);

        /// <inheritdoc />
        public Task ChangeDurationAsync(TimeSpan duration, CancellationToken cancellationToken = default) => _artist.ChangeDurationAsync(duration, cancellationToken);

        /// <inheritdoc />
        public Task StartDownloadOperationAsync(DownloadOperation operation, CancellationToken cancellationToken = default) => _artist.StartDownloadOperationAsync(operation, cancellationToken);

        /// <inheritdoc />
        public Task<bool> IsAddAlbumItemAvailableAsync(int index, CancellationToken cancellationToken = default) => _artist.IsAddAlbumItemAvailableAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task<bool> IsAddTrackAvailableAsync(int index, CancellationToken cancellationToken = default) => _artist.IsAddTrackAvailableAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task<bool> IsAddGenreAvailableAsync(int index, CancellationToken cancellationToken = default) => _artist.IsAddGenreAvailableAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task<bool> IsAddImageAvailableAsync(int index, CancellationToken cancellationToken = default) => _artist.IsAddImageAvailableAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task<bool> IsAddUrlAvailableAsync(int index, CancellationToken cancellationToken = default) => _artist.IsAddUrlAvailableAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task<bool> IsRemoveTrackAvailableAsync(int index, CancellationToken cancellationToken = default) => _artist.IsRemoveTrackAvailableAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task<bool> IsRemoveAlbumItemAvailableAsync(int index, CancellationToken cancellationToken = default) => _artist.IsRemoveAlbumItemAvailableAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task<bool> IsRemoveGenreAvailableAsync(int index, CancellationToken cancellationToken = default) => _artist.IsRemoveGenreAvailableAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task<bool> IsRemoveImageAvailableAsync(int index, CancellationToken cancellationToken = default) => _artist.IsRemoveImageAvailableAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task<bool> IsRemoveUrlAvailableAsync(int index, CancellationToken cancellationToken = default) => _artist.IsRemoveUrlAvailableAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task PlayAlbumCollectionAsync(IAlbumCollectionItem albumItem, CancellationToken cancellationToken = default) => _artist.PlayAlbumCollectionAsync(albumItem, cancellationToken);

        /// <inheritdoc />
        public Task PlayTrackCollectionAsync(ITrack track, CancellationToken cancellationToken = default) => _artist.PlayTrackCollectionAsync(track, cancellationToken);

        /// <inheritdoc />
        public IAsyncEnumerable<ITrack> GetTracksAsync(int limit, int offset, CancellationToken cancellationToken = default) => _artist.GetTracksAsync(limit, offset, cancellationToken);

        /// <inheritdoc />
        public IAsyncEnumerable<IAlbumCollectionItem> GetAlbumItemsAsync(int limit, int offset, CancellationToken cancellationToken = default) => _artist.GetAlbumItemsAsync(limit, offset, cancellationToken);

        /// <inheritdoc/>
        public IAsyncEnumerable<IImage> GetImagesAsync(int limit, int offset, CancellationToken cancellationToken = default) => _artist.GetImagesAsync(limit, offset, cancellationToken);

        /// <inheritdoc/>
        public IAsyncEnumerable<IGenre> GetGenresAsync(int limit, int offset, CancellationToken cancellationToken = default) => _artist.GetGenresAsync(limit, offset, cancellationToken);

        /// <inheritdoc/>
        public IAsyncEnumerable<IUrl> GetUrlsAsync(int limit, int offset, CancellationToken cancellationToken = default) => _artist.GetUrlsAsync(limit, offset, cancellationToken);

        /// <inheritdoc />
        public void SortAlbumCollection(AlbumSortingType albumSorting, SortDirection sortDirection)
        {
            CurrentAlbumSortingType = albumSorting;
            CurrentAlbumSortingDirection = sortDirection;

            CollectionSorting.SortAlbums(Albums, albumSorting, sortDirection, UnsortedAlbums);
        }

        /// <inheritdoc />
        public void SortTrackCollection(TrackSortingType trackSorting, SortDirection sortDirection)
        {
            CurrentTracksSortingType = trackSorting;
            CurrentTracksSortingDirection = sortDirection;

            CollectionSorting.SortTracks(Tracks, trackSorting, sortDirection, UnsortedTracks);
        }

        /// <inheritdoc />
        public async Task PopulateMoreAlbumsAsync(int limit, CancellationToken cancellationToken = default)
        {
            using (await Flow.EasySemaphore(_populateAlbumsMutex))
            {
                using var releaseReg = cancellationToken.Register(() => _populateAlbumsMutex.Release());

                _syncContext.Post(async _ =>
                {
                    await foreach (var item in _artist.GetAlbumItemsAsync(limit, Albums.Count, cancellationToken))
                    {
                        switch (item)
                        {
                            case IAlbum album:
                                var avm = new AlbumViewModel(album);
                                Albums.Add(avm);
                                UnsortedAlbums.Add(avm);
                                break;
                            case IAlbumCollection collection:
                                var acvm = new AlbumCollectionViewModel(collection);
                                Albums.Add(acvm);
                                UnsortedAlbums.Add(acvm);
                                break;
                        }
                    }
                }, null);
            }
        }

        /// <inheritdoc />
        public async Task PopulateMoreTracksAsync(int limit, CancellationToken cancellationToken = default)
        {
            using (await Flow.EasySemaphore(_populateTracksMutex))
            {
                using var releaseReg = cancellationToken.Register(() => _populateTracksMutex.Release());

                _syncContext.Post(async _ =>
                {
                    await foreach (var item in GetTracksAsync(limit, Tracks.Count, cancellationToken))
                    {
                        var tvm = new TrackViewModel(item);
                        Tracks.Add(tvm);
                        UnsortedTracks.Add(tvm);
                    }
                }, null);
            }
        }

        /// <inheritdoc />
        public async Task PopulateMoreImagesAsync(int limit, CancellationToken cancellationToken = default)
        {
            using (await Flow.EasySemaphore(_populateImagesMutex))
            {
                using var releaseReg = cancellationToken.Register(() => _populateImagesMutex.Release());

                _syncContext.Post(async _ =>
                {
                    await foreach (var item in _artist.GetImagesAsync(limit, Images.Count, cancellationToken))
                        Images.Add(item);
                }, null);
            }
        }

        /// <inheritdoc />
        public async Task PopulateMoreGenresAsync(int limit, CancellationToken cancellationToken = default)
        {
            using (await Flow.EasySemaphore(_populateGenresMutex))
            {
                using var releaseReg = cancellationToken.Register(() => _populateGenresMutex.Release());

                _syncContext.Post(async _ =>
                {
                    await foreach (var item in _artist.GetGenresAsync(limit, Genres.Count, cancellationToken))
                        Genres.Add(item);
                }, null);
            }
        }

        /// <inheritdoc />
        public async Task PopulateMoreUrlsAsync(int limit, CancellationToken cancellationToken = default)
        {
            using (await Flow.EasySemaphore(_populateUrlsMutex))
            {
                using var releaseReg = cancellationToken.Register(() => _populateUrlsMutex.Release());

                _syncContext.Post(async _ =>
                {
                    await foreach (var item in _artist.GetUrlsAsync(limit, Urls.Count, cancellationToken))
                    {
                        Urls.Add(item);
                    }
                }, null);
            }
        }

        /// <inheritdoc />
        public Task AddTrackAsync(ITrack track, int index, CancellationToken cancellationToken = default) => _artist.AddTrackAsync(track, index, cancellationToken);

        /// <inheritdoc />
        public Task AddAlbumItemAsync(IAlbumCollectionItem album, int index, CancellationToken cancellationToken = default) => _artist.AddAlbumItemAsync(album, index, cancellationToken);

        /// <inheritdoc/>
        public Task AddGenreAsync(IGenre genre, int index, CancellationToken cancellationToken = default) => _artist.AddGenreAsync(genre, index, cancellationToken);

        /// <inheritdoc />
        public Task AddImageAsync(IImage image, int index, CancellationToken cancellationToken = default) => _artist.AddImageAsync(image, index, cancellationToken);

        /// <inheritdoc />
        public Task AddUrlAsync(IUrl image, int index, CancellationToken cancellationToken = default) => _artist.AddUrlAsync(image, index, cancellationToken);

        /// <inheritdoc />
        public Task RemoveTrackAsync(int index, CancellationToken cancellationToken = default) => _artist.RemoveTrackAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task RemoveAlbumItemAsync(int index, CancellationToken cancellationToken = default) => _artist.RemoveAlbumItemAsync(index, cancellationToken);

        /// <inheritdoc/>
        public Task RemoveGenreAsync(int index, CancellationToken cancellationToken = default) => _artist.RemoveGenreAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task RemoveImageAsync(int index, CancellationToken cancellationToken = default) => _artist.RemoveImageAsync(index, cancellationToken);

        /// <inheritdoc />
        public Task RemoveUrlAsync(int index, CancellationToken cancellationToken = default) => _artist.RemoveUrlAsync(index, cancellationToken);

        /// <inheritdoc />
        public IAsyncRelayCommand<IAlbumCollectionItem> PlayAlbumAsyncCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand PlayAlbumCollectionAsyncCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand PauseAlbumCollectionAsyncCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand<ITrack> PlayTrackAsyncCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand PlayTrackCollectionAsyncCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand PauseTrackCollectionAsyncCommand { get; }

        /// <inheritdoc />
        public IRelayCommand<TrackSortingType> ChangeTrackCollectionSortingTypeCommand { get; }

        /// <inheritdoc />
        public IRelayCommand<SortDirection> ChangeTrackCollectionSortingDirectionCommand { get; }

        /// <inheritdoc />
        public IRelayCommand<AlbumSortingType> ChangeAlbumCollectionSortingTypeCommand { get; }

        /// <inheritdoc />
        public IRelayCommand<SortDirection> ChangeAlbumCollectionSortingDirectionCommand { get; }

        /// <summary>
        /// Command to change the name. It triggers <see cref="ChangeNameAsync"/>.
        /// </summary>
        public IAsyncRelayCommand<string> ChangeNameAsyncCommand { get; }

        /// <summary>
        /// Command to change the description. It triggers <see cref="ChangeDescriptionAsync"/>.
        /// </summary>
        public IAsyncRelayCommand<string?> ChangeDescriptionAsyncCommand { get; }

        /// <summary>
        /// Command to change the duration. It triggers <see cref="ChangeDurationAsync"/>.
        /// </summary>
        public IAsyncRelayCommand<TimeSpan> ChangeDurationAsyncCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand<int> PopulateMoreTracksCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand<int> PopulateMoreAlbumsCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand<int> PopulateMoreGenresCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand<int> PopulateMoreImagesCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand<int> PopulateMoreUrlsCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand InitAlbumCollectionAsyncCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand InitTrackCollectionAsyncCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand InitGenreCollectionAsyncCommand { get; }

        /// <inheritdoc />
        public IAsyncRelayCommand InitImageCollectionAsyncCommand { get; }

        /// <inheritdoc />
        public Task InitImageCollectionAsync(CancellationToken cancellationToken = default) => CollectionInit.ImageCollection(this, cancellationToken);

        /// <inheritdoc />
        public Task InitAlbumCollectionAsync(CancellationToken cancellationToken = default) => CollectionInit.AlbumCollection(this, cancellationToken);

        /// <inheritdoc />
        public Task InitTrackCollectionAsync(CancellationToken cancellationToken = default) => CollectionInit.TrackCollection(this, cancellationToken);

        /// <inheritdoc />
        public Task InitGenreCollectionAsync(CancellationToken cancellationToken = default) => CollectionInit.GenreCollection(this, cancellationToken);

        /// <inheritdoc />
        public bool Equals(ICoreArtistCollectionItem other) => _artist.Equals(other);

        /// <inheritdoc />
        public bool Equals(ICoreAlbumCollectionItem other) => _artist.Equals(other);

        /// <inheritdoc />
        public bool Equals(ICoreAlbumCollection other) => _artist.Equals(other);

        /// <inheritdoc />
        public bool Equals(ICoreTrackCollection other) => _artist.Equals(other);

        /// <inheritdoc />
        public bool Equals(ICoreGenreCollection other) => _artist.Equals(other);

        /// <inheritdoc />
        public bool Equals(ICoreImageCollection other) => _artist.Equals(other);

        /// <inheritdoc />
        public bool Equals(ICoreUrlCollection other) => _artist.Equals(other);

        /// <inheritdoc />
        public bool Equals(ICoreArtist other) => _artist.Equals(other);

        /// <inheritdoc />
        public Task InitAsync(CancellationToken cancellationToken = default)
        {
            if (IsInitialized)
                return Task.CompletedTask;

            IsInitialized = true;

            return Task.WhenAll(InitAlbumCollectionAsync(cancellationToken), InitGenreCollectionAsync(cancellationToken), InitImageCollectionAsync(cancellationToken), InitTrackCollectionAsync(cancellationToken));
        }

        private Task ChangeNameInternalAsync(string? name, CancellationToken cancellationToken = default)
        {
            Guard.IsNotNull(name, nameof(name));
            return _artist.ChangeNameAsync(name, cancellationToken);
        }

        /// <inheritdoc />
        public ValueTask DisposeAsync()
        {
            DetachEvents();
            return _artist.DisposeAsync();
        }
    }
}