'use strict';

// https://github.com/imathis/hsl-picker/blob/master/assets/javascripts/modules/color.coffee
const rHex3 = /^#[0-9a-f]{3}$/;
const rHex6 = /^#[0-9a-f]{6}$/;
const rRGB = /^rgba?\(\s*(\d{1,3})\s*,\s*(\d{1,3})\s*,\s*(\d{1,3})\s*,?\s*(0?\.?\d+)?\s*\)$/;
const rHSL = /^hsla?\(\s*(\d{1,3})\s*,\s*(\d{1,3})%\s*,\s*(\d{1,3})%\s*,?\s*(0?\.?\d+)?\s*\)$/;

// https://www.w3.org/TR/css3-color/#svg-color
const colorNames = {
  aliceblue: {r: 240, g: 248, b: 255, a: 1},
  antiquewhite: {r: 250, g: 235, b: 215, a: 1},
  aqua: {r: 0, g: 255, b: 255, a: 1},
  aquamarine: {r: 127, g: 255, b: 212, a: 1},
  azure: {r: 240, g: 255, b: 255, a: 1},
  beige: {r: 245, g: 245, b: 220, a: 1},
  bisque: {r: 255, g: 228, b: 196, a: 1},
  black: {r: 0, g: 0, b: 0, a: 1},
  blanchedalmond: {r: 255, g: 235, b: 205, a: 1},
  blue: {r: 0, g: 0, b: 255, a: 1},
  blueviolet: {r: 138, g: 43, b: 226, a: 1},
  brown: {r: 165, g: 42, b: 42, a: 1},
  burlywood: {r: 222, g: 184, b: 135, a: 1},
  cadetblue: {r: 95, g: 158, b: 160, a: 1},
  chartreuse: {r: 127, g: 255, b: 0, a: 1},
  chocolate: {r: 210, g: 105, b: 30, a: 1},
  coral: {r: 255, g: 127, b: 80, a: 1},
  cornflowerblue: {r: 100, g: 149, b: 237, a: 1},
  cornsilk: {r: 255, g: 248, b: 220, a: 1},
  crimson: {r: 220, g: 20, b: 60, a: 1},
  cyan: {r: 0, g: 255, b: 255, a: 1},
  darkblue: {r: 0, g: 0, b: 139, a: 1},
  darkcyan: {r: 0, g: 139, b: 139, a: 1},
  darkgoldenrod: {r: 184, g: 134, b: 11, a: 1},
  darkgray: {r: 169, g: 169, b: 169, a: 1},
  darkgreen: {r: 0, g: 100, b: 0, a: 1},
  darkgrey: {r: 169, g: 169, b: 169, a: 1},
  darkkhaki: {r: 189, g: 183, b: 107, a: 1},
  darkmagenta: {r: 139, g: 0, b: 139, a: 1},
  darkolivegreen: {r: 85, g: 107, b: 47, a: 1},
  darkorange: {r: 255, g: 140, b: 0, a: 1},
  darkorchid: {r: 153, g: 50, b: 204, a: 1},
  darkred: {r: 139, g: 0, b: 0, a: 1},
  darksalmon: {r: 233, g: 150, b: 122, a: 1},
  darkseagreen: {r: 143, g: 188, b: 143, a: 1},
  darkslateblue: {r: 72, g: 61, b: 139, a: 1},
  darkslategray: {r: 47, g: 79, b: 79, a: 1},
  darkslategrey: {r: 47, g: 79, b: 79, a: 1},
  darkturquoise: {r: 0, g: 206, b: 209, a: 1},
  darkviolet: {r: 148, g: 0, b: 211, a: 1},
  deeppink: {r: 255, g: 20, b: 147, a: 1},
  deepskyblue: {r: 0, g: 191, b: 255, a: 1},
  dimgray: {r: 105, g: 105, b: 105, a: 1},
  dimgrey: {r: 105, g: 105, b: 105, a: 1},
  dodgerblue: {r: 30, g: 144, b: 255, a: 1},
  firebrick: {r: 178, g: 34, b: 34, a: 1},
  floralwhite: {r: 255, g: 250, b: 240, a: 1},
  forestgreen: {r: 34, g: 139, b: 34, a: 1},
  fuchsia: {r: 255, g: 0, b: 255, a: 1},
  gainsboro: {r: 220, g: 220, b: 220, a: 1},
  ghostwhite: {r: 248, g: 248, b: 255, a: 1},
  gold: {r: 255, g: 215, b: 0, a: 1},
  goldenrod: {r: 218, g: 165, b: 32, a: 1},
  gray: {r: 128, g: 128, b: 128, a: 1},
  green: {r: 0, g: 128, b: 0, a: 1},
  greenyellow: {r: 173, g: 255, b: 47, a: 1},
  grey: {r: 128, g: 128, b: 128, a: 1},
  honeydew: {r: 240, g: 255, b: 240, a: 1},
  hotpink: {r: 255, g: 105, b: 180, a: 1},
  indianred: {r: 205, g: 92, b: 92, a: 1},
  indigo: {r: 75, g: 0, b: 130, a: 1},
  ivory: {r: 255, g: 255, b: 240, a: 1},
  khaki: {r: 240, g: 230, b: 140, a: 1},
  lavender: {r: 230, g: 230, b: 250, a: 1},
  lavenderblush: {r: 255, g: 240, b: 245, a: 1},
  lawngreen: {r: 124, g: 252, b: 0, a: 1},
  lemonchiffon: {r: 255, g: 250, b: 205, a: 1},
  lightblue: {r: 173, g: 216, b: 230, a: 1},
  lightcoral: {r: 240, g: 128, b: 128, a: 1},
  lightcyan: {r: 224, g: 255, b: 255, a: 1},
  lightgoldenrodyellow: {r: 250, g: 250, b: 210, a: 1},
  lightgray: {r: 211, g: 211, b: 211, a: 1},
  lightgreen: {r: 144, g: 238, b: 144, a: 1},
  lightgrey: {r: 211, g: 211, b: 211, a: 1},
  lightpink: {r: 255, g: 182, b: 193, a: 1},
  lightsalmon: {r: 255, g: 160, b: 122, a: 1},
  lightseagreen: {r: 32, g: 178, b: 170, a: 1},
  lightskyblue: {r: 135, g: 206, b: 250, a: 1},
  lightslategray: {r: 119, g: 136, b: 153, a: 1},
  lightslategrey: {r: 119, g: 136, b: 153, a: 1},
  lightsteelblue: {r: 176, g: 196, b: 222, a: 1},
  lightyellow: {r: 255, g: 255, b: 224, a: 1},
  lime: {r: 0, g: 255, b: 0, a: 1},
  limegreen: {r: 50, g: 205, b: 50, a: 1},
  linen: {r: 250, g: 240, b: 230, a: 1},
  magenta: {r: 255, g: 0, b: 255, a: 1},
  maroon: {r: 128, g: 0, b: 0, a: 1},
  mediumaquamarine: {r: 102, g: 205, b: 170, a: 1},
  mediumblue: {r: 0, g: 0, b: 205, a: 1},
  mediumorchid: {r: 186, g: 85, b: 211, a: 1},
  mediumpurple: {r: 147, g: 112, b: 219, a: 1},
  mediumseagreen: {r: 60, g: 179, b: 113, a: 1},
  mediumslateblue: {r: 123, g: 104, b: 238, a: 1},
  mediumspringgreen: {r: 0, g: 250, b: 154, a: 1},
  mediumturquoise: {r: 72, g: 209, b: 204, a: 1},
  mediumvioletred: {r: 199, g: 21, b: 133, a: 1},
  midnightblue: {r: 25, g: 25, b: 112, a: 1},
  mintcream: {r: 245, g: 255, b: 250, a: 1},
  mistyrose: {r: 255, g: 228, b: 225, a: 1},
  moccasin: {r: 255, g: 228, b: 181, a: 1},
  navajowhite: {r: 255, g: 222, b: 173, a: 1},
  navy: {r: 0, g: 0, b: 128, a: 1},
  oldlace: {r: 253, g: 245, b: 230, a: 1},
  olive: {r: 128, g: 128, b: 0, a: 1},
  olivedrab: {r: 107, g: 142, b: 35, a: 1},
  orange: {r: 255, g: 165, b: 0, a: 1},
  orangered: {r: 255, g: 69, b: 0, a: 1},
  orchid: {r: 218, g: 112, b: 214, a: 1},
  palegoldenrod: {r: 238, g: 232, b: 170, a: 1},
  palegreen: {r: 152, g: 251, b: 152, a: 1},
  paleturquoise: {r: 175, g: 238, b: 238, a: 1},
  palevioletred: {r: 219, g: 112, b: 147, a: 1},
  papayawhip: {r: 255, g: 239, b: 213, a: 1},
  peachpuff: {r: 255, g: 218, b: 185, a: 1},
  peru: {r: 205, g: 133, b: 63, a: 1},
  pink: {r: 255, g: 192, b: 203, a: 1},
  plum: {r: 221, g: 160, b: 221, a: 1},
  powderblue: {r: 176, g: 224, b: 230, a: 1},
  purple: {r: 128, g: 0, b: 128, a: 1},
  red: {r: 255, g: 0, b: 0, a: 1},
  rosybrown: {r: 188, g: 143, b: 143, a: 1},
  royalblue: {r: 65, g: 105, b: 225, a: 1},
  saddlebrown: {r: 139, g: 69, b: 19, a: 1},
  salmon: {r: 250, g: 128, b: 114, a: 1},
  sandybrown: {r: 244, g: 164, b: 96, a: 1},
  seagreen: {r: 46, g: 139, b: 87, a: 1},
  seashell: {r: 255, g: 245, b: 238, a: 1},
  sienna: {r: 160, g: 82, b: 45, a: 1},
  silver: {r: 192, g: 192, b: 192, a: 1},
  skyblue: {r: 135, g: 206, b: 235, a: 1},
  slateblue: {r: 106, g: 90, b: 205, a: 1},
  slategray: {r: 112, g: 128, b: 144, a: 1},
  slategrey: {r: 112, g: 128, b: 144, a: 1},
  snow: {r: 255, g: 250, b: 250, a: 1},
  springgreen: {r: 0, g: 255, b: 127, a: 1},
  steelblue: {r: 70, g: 130, b: 180, a: 1},
  tan: {r: 210, g: 180, b: 140, a: 1},
  teal: {r: 0, g: 128, b: 128, a: 1},
  thistle: {r: 216, g: 191, b: 216, a: 1},
  tomato: {r: 255, g: 99, b: 71, a: 1},
  turquoise: {r: 64, g: 224, b: 208, a: 1},
  violet: {r: 238, g: 130, b: 238, a: 1},
  wheat: {r: 245, g: 222, b: 179, a: 1},
  white: {r: 255, g: 255, b: 255, a: 1},
  whitesmoke: {r: 245, g: 245, b: 245, a: 1},
  yellow: {r: 255, g: 255, b: 0, a: 1},
  yellowgreen: {r: 154, g: 205, b: 50, a: 1}
};

const convertHue = (p, q, h) => {
  if (h < 0) h++;
  if (h > 1) h--;

  let color;

  if (h * 6 < 1) {
    color = p + ((q - p) * h * 6);
  } else if (h * 2 < 1) {
    color = q;
  } else if (h * 3 < 2) {
    color = p + ((q - p) * ((2 / 3) - h) * 6);
  } else {
    color = p;
  }

  return Math.round(color * 255);
};

const convertRGB = value => {
  const str = value.toString(16);
  if (value < 16) return `0${str}`;

  return str;
};

const mixValue = (a, b, ratio) => a + ((b - a) * ratio);

class Color {

  /**
   * @param {string|{ r: number; g: number; b: number; a: number;}} color
   */
  constructor(color) {
    if (typeof color === 'string') {
      this._parse(color);
    } else if (color != null && typeof color === 'object') {
      this.r = color.r | 0;
      this.g = color.g | 0;
      this.b = color.b | 0;
      this.a = +color.a;
    } else {
      throw new TypeError('color is required!');
    }

    if (this.r < 0 || this.r > 255
      || this.g < 0 || this.g > 255
      || this.b < 0 || this.b > 255
      || this.a < 0 || this.a > 1) {
      throw new RangeError(`{r: ${this.r}, g: ${this.g}, b: ${this.b}, a: ${this.a}} is invalid.`);
    }
  }

  /**
   * @param {string} color
   */
  _parse(color) {
    color = color.toLowerCase();

    if (Object.prototype.hasOwnProperty.call(colorNames, color)) {
      const obj = colorNames[color];

      this.r = obj.r;
      this.g = obj.g;
      this.b = obj.b;
      this.a = obj.a;

      return;
    }

    if (rHex3.test(color)) {
      const txt = color.substring(1);
      const code = parseInt(txt, 16);

      this.r = ((code & 0xF00) >> 8) * 17;
      this.g = ((code & 0xF0) >> 4) * 17;
      this.b = (code & 0xF) * 17;
      this.a = 1;

      return;
    }

    if (rHex6.test(color)) {
      const txt = color.substring(1);
      const code = parseInt(txt, 16);

      this.r = (code & 0xFF0000) >> 16;
      this.g = (code & 0xFF00) >> 8;
      this.b = code & 0xFF;
      this.a = 1;

      return;
    }

    let match = color.match(rRGB);

    if (match) {
      this.r = match[1] | 0;
      this.g = match[2] | 0;
      this.b = match[3] | 0;
      this.a = match[4] ? +match[4] : 1;

      return;
    }

    match = color.match(rHSL);

    if (match) {
      const h = +match[1] / 360;
      const s = +match[2] / 100;
      const l = +match[3] / 100;

      this.a = match[4] ? +match[4] : 1;

      if (!s) {
        this.r = l * 255;
        this.g = this.r;
        this.b = this.r;
      }

      const q = l < 0.5 ? l * (1 + s) : l + s - (l * s);
      const p = (2 * l) - q;

      const rt = h + (1 / 3);
      const gt = h;
      const bt = h - (1 / 3);

      this.r = convertHue(p, q, rt);
      this.g = convertHue(p, q, gt);
      this.b = convertHue(p, q, bt);

      return;
    }

    throw new Error(`${color} is not a supported color format.`);
  }

  toString() {
    if (this.a === 1) {
      const r = convertRGB(this.r);
      const g = convertRGB(this.g);
      const b = convertRGB(this.b);

      if (this.r % 17 || this.g % 17 || this.b % 17) {
        return `#${r}${g}${b}`;
      }

      return `#${r[0]}${g[0]}${b[0]}`;
    }

    return `rgba(${this.r}, ${this.g}, ${this.b}, ${parseFloat(this.a.toFixed(2))})`;
  }

  /**
   * @param {string|{ r: number; g: number; b: number; a: number;}} color
   * @param {number} ratio
   */
  mix(color, ratio) {
    if (ratio > 1 || ratio < 0) {
      throw new RangeError('Valid numbers is only between 0 and 1.');
    }
    switch (ratio) {
      case 0:
        return new Color(this);

      case 1:
        return new Color(color);
    }

    return new Color({
      r: Math.round(mixValue(this.r, color.r, ratio)),
      g: Math.round(mixValue(this.g, color.g, ratio)),
      b: Math.round(mixValue(this.b, color.b, ratio)),
      a: mixValue(this.a, color.a, ratio)
    });
  }
}

module.exports = Color;