#if WINDOWS
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;

namespace MeetingAssistant.Screenshots;

internal sealed class WindowsScreenshotImageCropper : IScreenshotImageCropper
{
#pragma warning disable CA1416
    public Task<string?> SaveCroppedScreenshotAsync(
        string screenshotPath,
        ScreenshotCropCoordinates crop,
        CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();
        try
        {
            using var original = new Bitmap(screenshotPath);
            ValidateCrop(crop, original.Width, original.Height);
            var cropRectangle = new Rectangle(crop.X, crop.Y, crop.Width, crop.Height);
            using var cropped = original.Clone(cropRectangle, original.PixelFormat);
            var croppedPath = Path.Combine(
                Path.GetDirectoryName(screenshotPath)!,
                $"{Path.GetFileNameWithoutExtension(screenshotPath)}-cropped.png");
            cropped.Save(croppedPath, ImageFormat.Png);
            return Task.FromResult<string?>(croppedPath);
        }
        catch (ExternalException exception)
        {
            throw new InvalidDataException(
                $"The screenshot crop {crop.X},{crop.Y},{crop.Width},{crop.Height} could not be applied.",
                exception);
        }
    }
#pragma warning restore CA1416

    private static void ValidateCrop(
        ScreenshotCropCoordinates crop,
        int imageWidth,
        int imageHeight)
    {
        if (crop.X < 0 ||
            crop.Y < 0 ||
            crop.Width <= 0 ||
            crop.Height <= 0 ||
            crop.X + crop.Width > imageWidth ||
            crop.Y + crop.Height > imageHeight)
        {
            throw new InvalidDataException(
                $"Screenshot crop {crop.X},{crop.Y},{crop.Width},{crop.Height} is outside image bounds {imageWidth}x{imageHeight}.");
        }
    }
}
#endif