using o0.Geometry2D.Float;
using o0InfraredLocate.ZIM;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Unity.VisualScripting;
using UnityEngine;
using UnityEngine.Internal;

namespace ZIM.Unity
{
    public static partial class Extension
    {

        public static UnityEngine.Color UnityColor(this o0.Color c)
        {
            return new UnityEngine.Color(c.r, c.g, c.b, c.a);
        }

        public static o0.Color o0Color(this UnityEngine.Color c)
        {
            return new o0.Color(c.r, c.g, c.b, c.a);
        }

        public static Texture2D zimAutoLightSimple(this WebCamTexture texture)
        {
            var pixel = texture.GetPixels();
            return pixel.zimAutoLightSimple(texture.width, texture.height);
        }

        public static Texture2D zimAutoLightSimple(this Texture2D texture)
        {
            var pixel = texture.GetPixels();
            return pixel.zimAutoLightSimple(texture.width, texture.height);
        }

        public static Vector2 Size(this Texture2D texture)
        {
            return new Vector2(texture.width, texture.height);
        }

        // 亮点放大到1
        public static Texture2D zimAutoLightSpot(this WebCamTexture texture)
        {
            var pixel = texture.GetPixels();
            float[] brightness = new float[pixel.Length];
            Parallel.For(0, pixel.Length, (i) => brightness[i] = pixel[i].Brightness());

            var max = Enumerable.Max(brightness);
            var scale = max >= 0.5f ? 1 / max : 1.3f;        // 设个阈值 0.5

            Parallel.For(0, pixel.Length, (i) => pixel[i] = pixel[i].RGBMutiply(scale));

            var tex = new Texture2D(texture.width, texture.height);
            tex.SetPixels(pixel);
            tex.Apply();
            return tex;
        }

        public static Texture2D zimAutoLight(this WebCamTexture texture)
        {
            var pixel = texture.GetPixels();
            return zimAutoLight(pixel, texture.width, texture.height, 0);
        }
        public static Texture2D zimAutoLight(this Texture2D texture, int brightness)
        {
            var pixel = texture.GetPixels();
            return zimAutoLight(pixel, texture.width, texture.height, brightness);
        }
        public static Texture2D zimAutoLight(this Color[] pixel, int width, int height, [DefaultValue("0")] int brightness)
        {
            float[] p = new float[pixel.Length];
            Parallel.For(0, pixel.Length, (i) => p[i] = pixel[i].Brightness());

            var scale = 1 / Enumerable.Max(p) * (2 + brightness);
            if (float.IsInfinity(scale))
                return null;
            Parallel.For(0, p.Length, (i) => pixel[i] = pixel[i].RGBMutiply(scale));        // 归一化

            var tex = new Texture2D(width, height);
            tex.SetPixels(pixel);
            tex.Apply();
            return tex;
        }

        public static Texture2D zimAutoLevelEqualization(this WebCamTexture texture, int bit = 256)
        {
            var pixel = texture.GetPixels();
            float[] p = new float[pixel.Length];
            Parallel.For(0, pixel.Length, (i) => p[i] = pixel[i].r);        // 红通道

            bit -= 1;
            var scale = 1 / Enumerable.Max(p);
            if (float.IsInfinity(scale))
                return null;
            Parallel.For(0, p.Length, (i) => p[i] *= scale);        // 归一化

            int[] pint = new int[p.Length];
            Parallel.For(0, p.Length, i => pint[i] = (int)(p[i] * bit));        // 映射到256色彩

            //Debug.Log(Enumerable.Max(pint) + ", " + scale);

            int[] H = new int[bit + 1];
            for (int i = 0; i < p.Length; i++)
                H[pint[i]]++;
            float[] HF = new float[bit + 1];
            for (int i = 0; i <= bit; i++)
                HF[i] = H[i] / (float)p.Length;       // 概率

            float[] D = new float[bit + 1];
            float temp = 0;
            for (int i = 1; i <= bit; i++)      // 不取颜色为0的概率
            {
                temp += HF[i];
                D[i] = temp;        // 累计密度
            }
            Parallel.For(0, p.Length, i => p[i] = D[pint[i]] / D.Last());       // 取密度为颜色，并归一化

            UnityEngine.Color[] pixelLighted = new UnityEngine.Color[pixel.Length];
            Parallel.For(0, pixel.Length, (i) => pixelLighted[i] = new UnityEngine.Color(p[i], 0, 0));
            var tex = new Texture2D(texture.width, texture.height);
            tex.SetPixels(pixelLighted);
            tex.Apply();
            return tex;
        }


        public static void CopyTo(this RenderTexture src, Texture2D dst)
        {
            var pre = RenderTexture.active;

            RenderTexture.active = src;
            dst.ReadPixels(new Rect(0, 0, src.width, src.height), 0, 0);
            dst.Apply();

            RenderTexture.active = pre;
        }
    }

}