using System;
using System.Collections.Generic;
using System.Drawing;
using System.Text;

namespace HTEXLib
{
    /// <summary>
    /// 类      名：ColorHelper
    /// 功      能：提供从RGB到HSV/HSL色彩空间的相互转换
    /// </summary>
    public static class ColorHelper
    {
        /// <summary>
        /// RGB转换HSV
        /// </summary>
        /// <param name="rgb"></param>
        /// <returns></returns>
        public static ColorHSV RgbToHsv(this ColorRGB rgb)
        {
            double min, max, tmp, H, S, V;
            double R = rgb.R * 1.0f / 255, G = rgb.G * 1.0f / 255, B = rgb.B * 1.0f / 255;
            tmp = System.Math.Min(R, G);
            min = System.Math.Min(tmp, B);
            tmp = System.Math.Max(R, G);
            max = System.Math.Max(tmp, B);
            // H
            H = 0;
            if (max == min)
            {
                H = 0;
            }
            else if (max == R && G > B)
            {
                H = 60 * (G - B) * 1.0f / (max - min) + 0;
            }
            else if (max == R && G < B)
            {
                H = 60 * (G - B) * 1.0f / (max - min) + 360;
            }
            else if (max == G)
            {
                H = H = 60 * (B - R) * 1.0f / (max - min) + 120;
            }
            else if (max == B)
            {
                H = H = 60 * (R - G) * 1.0f / (max - min) + 240;
            }
            // S
            if (max == 0)
            {
                S = 0;
            }
            else
            {
                S = (max - min) * 1.0f / max;
            }
            // V
            V = max;
            return new ColorHSV((int)H, (int)(S * 255), (int)(V * 255));
        }

        /// <summary>
        /// HSV转换RGB
        /// </summary>
        /// <param name="hsv"></param>
        /// <returns></returns>
        public static ColorRGB HsvToRgb( this ColorHSV hsv)
        {
            if (hsv.H == 360) hsv.H = 359; // 360为全黑，原因不明
            double R = 0f, G = 0f, B = 0f;
            if (hsv.S == 0)
            {
                return new ColorRGB(hsv.V, hsv.V, hsv.V);
            }
            double S = hsv.S * 1.0f / 255, V = hsv.V * 1.0f / 255;
            int H1 = (int)(hsv.H * 1.0f / 60), H = hsv.H;
            double F = H * 1.0f / 60 - H1;
            double P = V * (1.0f - S);
            double Q = V * (1.0f - F * S);
            double T = V * (1.0f - (1.0f - F) * S);
            switch (H1)
            {
                case 0: R = V; G = T; B = P; break;
                case 1: R = Q; G = V; B = P; break;
                case 2: R = P; G = V; B = T; break;
                case 3: R = P; G = Q; B = V; break;
                case 4: R = T; G = P; B = V; break;
                case 5: R = V; G = P; B = Q; break;
            }
            R = R * 255;
            G = G * 255;
            B = B * 255;
            while (R > 255) R -= 255;
            while (R < 0) R += 255;
            while (G > 255) G -= 255;
            while (G < 0) G += 255;
            while (B > 255) B -= 255;
            while (B < 0) B += 255;
            return new ColorRGB((int)R, (int)G, (int)B);
        }

        /// <summary>
        /// RGB转换HSL
        /// </summary>
        /// <param name="rgb"></param>
        /// <returns></returns>
        public static ColorHSL RgbToHsl( this ColorRGB rgb)
        {
            double min, max, tmp, H = 0, S = 0, L = 0;
            double R = rgb.R * 1.0f / 255, G = rgb.G * 1.0f / 255, B = rgb.B * 1.0f / 255;
            tmp = System.Math.Min(R, G);
            min = System.Math.Min(tmp, B);
            tmp = System.Math.Max(R, G);
            max = System.Math.Max(tmp, B);
            L = (max + min) / 2.0d;
            if (min == max)
            {
                H = S = 0;
            }
            else
            {
                double d = max - min;
                S = L > 0.5 ? d / (2 - max - min) : d / (max + min);
                if (max == R)
                {
                    H = (G - B) / d + (G < B ? 6 : 0);
                }
                else if (max == G)
                {
                    H = (G - R) / d + 2;
                }
                else if (max == B)
                {
                    H = (R - G) / d + 4;
                }
            }
            H = H / 6.0F;
            return new ColorHSL() { H = H, S = S, L = L };
        }

        public static double hue2rgb(double p, double q, double t)
        {
            if (t < 0) t += 1;

            if (t > 1) t -= 1;

            if (t < 1.0 / 6.0d) return p + (q - p) * 6 * t;

            if (t < 1.0 / 2.0d) return q;

            if (t < 2.0 / 3.0d) return p + (q - p) * (2.0d / 3.0d - t) * 6.0d;

            return p;
        }

        /// <summary>
        /// HSL转换RGB
        /// </summary>
        /// <param name="hsl"></param>
        /// <returns></returns>
        public static ColorRGB HslToRgb( this ColorHSL hsl)
        {
            var l = hsl.L;
            var s = hsl.S;
            var h = hsl.H;
            double R = 0, G = 0, B = 0;
            if (hsl.S == 0)
            {
                R = G = B = hsl.L;
            }
            else
            {
                var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
                var p = 2 * l - q;
                R = hue2rgb(p, q, h + 1.0d / 3.0d);
                G = hue2rgb(p, q, h);
                B = hue2rgb(p, q, h - 1.0d / 3.0d);
            }
            R = R * 255; G = G * 255; B = B * 255;
            return new ColorRGB(int.Parse(System.Math.Round(R, 0) + ""), int.Parse(System.Math.Round(G, 0) + ""), int.Parse(System.Math.Round(B, 0) + ""));
        }
        private static double HueToRGB(double p, double q, double h)
        {
            if (h < 0) h += 1;
            if (h > 1) h -= 1;
            if (6 * h < 1)
            {
                return p + ((q - p) * 6 * h);
            }
            if (2 * h < 1)
            {
                return q;
            }
            if (3 * h < 2)
            {
                return p + ((q - p) * 6 * ((2.0f / 3.0f) - h));
            }
            return p;
        }
        /// <summary>
        /// 处理图像饱和度
        /// </summary>
        /// <param name="color"></param>
        /// <param name="lumMod"></param>
        /// <param name="lumOff"></param>
        /// <returns></returns>
        public static string GetColorLumModAndLumOff(Color color, int lumMod = 0, int lumOff = 0)
        {
            ColorHSL colorHSL = RgbToHsl(new ColorRGB(color.R, color.G, color.B));
            colorHSL.L = colorHSL.L * lumMod / 100_000.0 + lumOff / 100_000.0;
            ColorRGB colorRGB = HslToRgb(colorHSL);
            return ColorTranslator.ToHtml(Color.FromArgb(colorRGB.R, colorRGB.G, colorRGB.B)).Replace("#","");
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="color">原色RGB</param>
        /// <param name="pa">混合原色占百分比/100% </param>
        /// <param name="Type">Shade 与黑色混合  Tint与白色混合</param>
        /// <returns></returns>
        public static string  GetShadeOrTintColor(Color color, double val, string Type)
        {
            ColorConverter converter = new ColorConverter();
            if (Type.Equals("Shade"))
            {
                return converter.SetShade(color, val);
            }
            else if (Type.Equals("Tint"))
            {
                return converter.SetTint(color, val);
            }
            else { return ColorTranslator.ToHtml(color).Replace("#",""); }
        }

    }
}