using System.Collections.Generic;
using System.Runtime.CompilerServices;
using Sprite = Glass.SpriteMaterial;

namespace Glass.Testbed
{
    /// <summary>
    /// The four cells of ResizeCursors.png, laid out as a 2x2 grid with no border between cells.
    /// </summary>
    [SpriteSheet(spriteSizeX: 16, spriteSizeY: 16, borderSize: 0,
        "Glass.Testbed.SampleMaterials.ResizeCursors.png")]
    public sealed class ResizeCursorMaterials
    {
        public static readonly Sprite Horizontal = CreateIcon(0, 0);
        public static readonly Sprite Vertical = CreateIcon(1, 0);
        public static readonly Sprite DiagonalNwSe = CreateIcon(0, 1);
        public static readonly Sprite DiagonalNeSw = CreateIcon(1, 1);

        /// <summary>
        /// A cursor for every ResizeZone, for a ResizablePanel's ResizeCursors.
        /// </summary>
        public static readonly IReadOnlyDictionary<ResizeZone, Cursor> ByZone = BuildByZone();

        private static Sprite CreateIcon(int x, int y, [CallerMemberName] string debugName = "")
        {
            return MaterialLibrary<ResizeCursorMaterials>.CreateSprite(new Point(x, y), debugName);
        }

        private static IReadOnlyDictionary<ResizeZone, Cursor> BuildByZone()
        {
            // One cursor per arrow, shared by the two zones each double-headed arrow serves.
            var center = new Point(8, 8);
            Cursor horizontal = new SpriteCursor(Horizontal, center);
            Cursor vertical = new SpriteCursor(Vertical, center);
            Cursor diagonalNwSe = new SpriteCursor(DiagonalNwSe, center);
            Cursor diagonalNeSw = new SpriteCursor(DiagonalNeSw, center);

            return new Dictionary<ResizeZone, Cursor>
            {
                [ResizeZone.E] = horizontal,
                [ResizeZone.W] = horizontal,
                [ResizeZone.N] = vertical,
                [ResizeZone.S] = vertical,
                [ResizeZone.NW] = diagonalNwSe,
                [ResizeZone.SE] = diagonalNwSe,
                [ResizeZone.NE] = diagonalNeSw,
                [ResizeZone.SW] = diagonalNeSw,
            };
        }
    }
}