using Avalonia.Controls;
using Avalonia.Input;
using Avalonia.Interactivity;
using Avalonia.Media.Imaging;
using Avalonia.Threading;
using Harmonia.Core.Caching;
using Harmonia.Core.Imaging;
using Harmonia.Core.Playlists;
using Harmonia.UI.ViewModels;
using Microsoft.Extensions.Caching.Memory;
using System;
using System.Collections.Concurrent;
using System.IO;
using System.Threading;
using System.Threading.Tasks;

namespace Harmonia.UI.Views;

public partial class PlaylistView : UserControl
{
    private readonly PlaylistViewModel _viewModel;
    private readonly ConcurrentDictionary<int, CancellationTokenSource> _imageCancellationTokens = [];

    public PlaylistView()
    {
        InitializeComponent();
        _viewModel = (PlaylistViewModel)DataContext!;
    }

    private void ListBox_DoubleTapped(object? sender, TappedEventArgs e)
    {
        if (sender is ListBox listBox && listBox.SelectedItem is PlaylistSong playlistSong)
        {
            _viewModel.PlaySong(playlistSong);
        }
    }

    private void Image_Loaded(object? sender, RoutedEventArgs e)
    {
        if (sender is not Image image)
            return;

        if (image.DataContext is not PlaylistSong playlistSong)
            return;

        Task.Run(() => DoSomethingAsync(image, playlistSong));
    }

    private async Task DoSomethingAsync(Image image, PlaylistSong playlistSong)
    {
        int hashCode = image.GetHashCode();

        _imageCancellationTokens.TryGetValue(hashCode, out CancellationTokenSource? cancellationTokenSource);
        cancellationTokenSource?.Cancel();

        cancellationTokenSource = new();

        Bitmap? bitmap = await _viewModel.GetBitmapAsync(playlistSong, cancellationTokenSource.Token);

        if (bitmap == null)
            return;

        await Dispatcher.UIThread.InvokeAsync(() => SetSongImageSource(image, bitmap));
    }

    private static void SetSongImageSource(Image image, Bitmap bitmap)
    {
        image.Source = bitmap;
    }

    private void Image_Unloaded(object? sender, RoutedEventArgs e)
    {
        if (sender is not Image image)
            return;

        if (image.DataContext is not PlaylistSong playlistSong)
            return;

        if (image.Source is Bitmap bitmap)
        {
            bitmap.Dispose();
        }

        image.Source = null;

        int hashCode = image.GetHashCode();

        _imageCancellationTokens.TryGetValue(hashCode, out CancellationTokenSource? cancellationTokenSource);
        cancellationTokenSource?.Cancel();
    }
}