using Avalonia.Controls;
using Avalonia.Input;
using Avalonia.Media.Imaging;
using LindtLeerformPlugin.ViewModels;

namespace LindtLeerformPlugin.Views;

public partial class CalibrationWindow : Window
{
    private static readonly Cursor HandCursor = new(StandardCursorType.Hand);
    private static readonly Cursor DefaultCursor = new(StandardCursorType.Arrow);

    public CalibrationWindow()
    {
        InitializeComponent();

        PreviewImageControl.PointerMoved += OnPreviewPointerMoved;
        PreviewImageControl.PointerPressed += OnPreviewPointerPressed;
        PreviewImageControl.PointerExited += OnPreviewPointerExited;
    }

    protected override void OnClosing(WindowClosingEventArgs e)
    {
        (DataContext as CalibrationWindowViewModel)?.Dispose();
        base.OnClosing(e);
    }

    private (int x, int y)? ToImageCoordinates(Avalonia.Point pointerPos)
    {
        if (PreviewImageControl.Source is not Bitmap bitmap)
            return null;

        var ctrlSize = PreviewImageControl.Bounds.Size;
        var imgSize = bitmap.Size;
        if (ctrlSize.Width <= 0 || ctrlSize.Height <= 0 || imgSize.Width <= 0 || imgSize.Height <= 0)
            return null;

        var scale = System.Math.Min(ctrlSize.Width / imgSize.Width, ctrlSize.Height / imgSize.Height);
        var displayW = imgSize.Width * scale;
        var displayH = imgSize.Height * scale;
        var offsetX = (ctrlSize.Width - displayW) / 2;
        var offsetY = (ctrlSize.Height - displayH) / 2;

        var imgX = (pointerPos.X - offsetX) / scale;
        var imgY = (pointerPos.Y - offsetY) / scale;

        if (imgX < 0 || imgY < 0 || imgX >= imgSize.Width || imgY >= imgSize.Height)
            return null;

        return ((int)imgX, (int)imgY);
    }

    private void OnPreviewPointerMoved(object? sender, PointerEventArgs e)
    {
        if (DataContext is not CalibrationWindowViewModel vm)
            return;

        var coords = ToImageCoordinates(e.GetPosition(PreviewImageControl));
        if (coords == null)
        {
            PreviewImageControl.Cursor = DefaultCursor;
            return;
        }

        var cellIndex = vm.HitTestCell(coords.Value.x, coords.Value.y);
        PreviewImageControl.Cursor = cellIndex.HasValue ? HandCursor : DefaultCursor;
    }

    private void OnPreviewPointerExited(object? sender, PointerEventArgs e)
    {
        PreviewImageControl.Cursor = DefaultCursor;
    }

    private async void OnPreviewPointerPressed(object? sender, PointerPressedEventArgs e)
    {
        if (DataContext is not CalibrationWindowViewModel vm)
            return;
        if (!e.GetCurrentPoint(PreviewImageControl).Properties.IsLeftButtonPressed)
            return;

        var coords = ToImageCoordinates(e.GetPosition(PreviewImageControl));
        if (coords == null)
            return;

        await vm.ShowCellHistogramAsync(coords.Value.x, coords.Value.y, this);
    }
}