using System;
using System.Linq;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using Chernobyl.Mathematics;
using Chernobyl.Mathematics.Geometry;
using Chernobyl.Mathematics.Vectors;

namespace Chernobyl.App.Patterns
{
    /// <summary>
    /// Extensions for working with WPF images.
    /// </summary>
    public static class Image
    {
        /// <summary>
        /// Creates a bitmap image using the color function.
        /// </summary>
        /// <param name="factory">A method that outputs a value based on a normalized (0 to 1)
        /// position it is given. For X, 0 is the left most side and 1 is the right most. For Y,
        /// 0 is the bottom most and 1 the top most.</param>
        /// <param name="width">The horizontal size of the 2D image. Must be at least 2.</param>
        /// <param name="height">The vertical size of the 2D image. Must be at least 2.</param>
        public static ImageSource CreateBitmap(this Func<Vector2d, Graphics.ColorRgba> factory, int width, int height)
        {
            var pixels = factory
                .To1D(width, height)
                .SelectMany(color => color.Bgra.AsEnumerable())
                .ToArray();

            Int32Rect rect = new Int32Rect(0, 0, width, height);
            int stride = 4 * width;

            var bitmap = new WriteableBitmap(width, height, 96, 96, PixelFormats.Bgra32, null);
            bitmap.WritePixels(rect, pixels, stride, 0);

            return bitmap;
        }
    }
}