using System.Linq;
using System.Text;
using Superlazy;
using UnityEngine;

public class SpriteText : SLTag
{
    public override string Tag => "ST";

    private Texture2D baseTex;

    public override string GetValue(SLEntity value)
    {
        if (baseTex == null) InitTexture();

        if (SLGame.Session["SpriteTexts"][value] == false)
        {
            var path = SLSystem.Data["ImageSprites"][value]["Path"];
            if (path == false) return value;
            var sprite = SLResources.GetSprite(path);

            var spritePixels = Clone(sprite.texture, sprite.textureRect).GetPixels();

            var targetPixels = Resize(spritePixels, Mathf.RoundToInt(sprite.rect.width), Mathf.RoundToInt(sprite.rect.height), 128, 128);

            var idx = SLGame.Session["SpriteTexts"].Count();
            SLGame.Session["SpriteTexts"][value]["Index"] = idx;
            var baseX = idx % 16 * 128;
            var baseY = (2048 - 128) - (idx / 16 * 128);

            for (var x = 0; x < 128; ++x)
            {
                for (var y = 0; y < 128; ++y)
                {
                    var color = targetPixels[y * 128 + x];

                    baseTex.SetPixel(x + baseX, y + baseY, color);
                }
            }

            baseTex.Apply(false);
        }

        return $"<sprite={SLGame.Session["SpriteTexts"][value]["Index"]}>"; // "Sprite=0" 같은 형태
    }

    private void InitTexture()
    {
        baseTex = Resources.Load<Texture2D>("SpriteTextBase");
    }

    private Texture2D Clone(Texture2D source, Rect rect)
    {
        // 새 텍스처를 스프라이트 크기로 생성
        var readableTexture = new Texture2D((int)rect.width, (int)rect.height, TextureFormat.RGBA32, false);

        // 원본 텍스처에서 스프라이트 영역의 픽셀을 읽어들임
        var renderTex = RenderTexture.GetTemporary(source.width, source.height, 0);
        Graphics.Blit(source, renderTex);

        // 읽을 영역을 설정 (rect를 사용하여 원본에서 스프라이트 부분만 읽음)
        RenderTexture.active = renderTex;
        readableTexture.ReadPixels(new Rect(rect.x, rect.y, rect.width, rect.height), 0, 0);
        readableTexture.Apply();

        RenderTexture.active = null;
        RenderTexture.ReleaseTemporary(renderTex);

        return readableTexture;
    }

    private Color[] Resize(Color[] colors, int sourceWidth, int sourceHeight, int targetWidth, int targetHeight)
    {
        var ret = new Color[targetWidth * targetHeight];

        var ratioX = 1.0f / ((float)targetWidth / (sourceWidth - 1));
        var ratioY = 1.0f / ((float)targetHeight / (sourceWidth - 1));
        for (var y = 0; y < targetHeight; y++)
        {
            var yFloor = Mathf.FloorToInt(y * ratioY);
            for (var x = 0; x < targetWidth; x++)
            {
                var xFloor = Mathf.FloorToInt(x * ratioX);
                var c1 = colors[xFloor * sourceHeight + yFloor];
                var c2 = colors[xFloor * sourceHeight + yFloor];
                var c3 = colors[xFloor * sourceHeight + yFloor + 1];
                var c4 = colors[(xFloor + 1) * sourceHeight + yFloor + 1];

                var xLerp = x * ratioX - xFloor;
                var yLerp = y * ratioY - yFloor;

                var top = Color.Lerp(c1, c2, xLerp);
                var bottom = Color.Lerp(c3, c4, xLerp);
                ret[x * targetHeight + y] = Color.Lerp(top, bottom, yLerp);
            }
        }
        return ret;
    }
}