using System.Windows;
using EmbyToolbox.ViewModels;

namespace EmbyToolbox.Behaviors;

public static class ConversionQueueDropTargetBehavior
{
    public static readonly DependencyProperty IsDropTargetEnabledProperty = DependencyProperty.RegisterAttached(
        "IsDropTargetEnabled",
        typeof(bool),
        typeof(ConversionQueueDropTargetBehavior),
        new PropertyMetadata(false, OnIsDropTargetEnabledChanged));

    public static void SetIsDropTargetEnabled(DependencyObject d, bool value) => d.SetValue(IsDropTargetEnabledProperty, value);
    public static bool GetIsDropTargetEnabled(DependencyObject d) => (bool)d.GetValue(IsDropTargetEnabledProperty);

    private static void OnIsDropTargetEnabledChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (d is not UIElement el)
        {
            return;
        }

        if (e.OldValue is true)
        {
            el.PreviewDragOver -= OnPreviewDragOver;
            el.DragLeave -= OnDragLeave;
            el.Drop -= OnDrop;
        }

        if (e.NewValue is not true)
        {
            return;
        }

        el.AllowDrop = true;
        el.PreviewDragOver += OnPreviewDragOver;
        el.DragLeave += OnDragLeave;
        el.Drop += OnDrop;
    }

    private static void OnDragLeave(object sender, DragEventArgs e)
    {
        if (sender is not FrameworkElement fe)
        {
            return;
        }

        if (fe.DataContext is ConversionViewModel vm)
        {
            vm.IsQueueDropHighlight = false;
        }
    }

    private static void OnPreviewDragOver(object sender, DragEventArgs e)
    {
        if (sender is not FrameworkElement fe)
        {
            return;
        }

        if (fe.DataContext is not ConversionViewModel vm)
        {
            return;
        }

        if (e.Data.GetDataPresent(DataFormats.FileDrop))
        {
            e.Effects = DragDropEffects.Copy;
            e.Handled = true;
            vm.IsQueueDropHighlight = true;
            return;
        }

        e.Effects = DragDropEffects.None;
        vm.IsQueueDropHighlight = false;
    }

    private static void OnDrop(object sender, DragEventArgs e)
    {
        if (sender is not FrameworkElement fe)
        {
            return;
        }

        if (fe.DataContext is not ConversionViewModel vm)
        {
            return;
        }

        vm.IsQueueDropHighlight = false;

        if (e.Data.GetData(DataFormats.FileDrop) is not string[] paths || paths.Length == 0)
        {
            e.Handled = true;
            return;
        }

        vm.ProcessPathsDroppedOnQueue(paths);
        e.Handled = true;
    }
}