/**
 * For parsing color values
 * @module RGBColor
 * @author Stoyan Stefanov <sstoo@gmail.com>
 * @see https://www.phpied.com/rgb-color-parser-in-javascript/
 * @license MIT
*/
const simpleColors = {
  aliceblue: 'f0f8ff',
  antiquewhite: 'faebd7',
  aqua: '00ffff',
  aquamarine: '7fffd4',
  azure: 'f0ffff',
  beige: 'f5f5dc',
  bisque: 'ffe4c4',
  black: '000000',
  blanchedalmond: 'ffebcd',
  blue: '0000ff',
  blueviolet: '8a2be2',
  brown: 'a52a2a',
  burlywood: 'deb887',
  cadetblue: '5f9ea0',
  chartreuse: '7fff00',
  chocolate: 'd2691e',
  coral: 'ff7f50',
  cornflowerblue: '6495ed',
  cornsilk: 'fff8dc',
  crimson: 'dc143c',
  cyan: '00ffff',
  darkblue: '00008b',
  darkcyan: '008b8b',
  darkgoldenrod: 'b8860b',
  darkgray: 'a9a9a9',
  darkgreen: '006400',
  darkkhaki: 'bdb76b',
  darkmagenta: '8b008b',
  darkolivegreen: '556b2f',
  darkorange: 'ff8c00',
  darkorchid: '9932cc',
  darkred: '8b0000',
  darksalmon: 'e9967a',
  darkseagreen: '8fbc8f',
  darkslateblue: '483d8b',
  darkslategray: '2f4f4f',
  darkturquoise: '00ced1',
  darkviolet: '9400d3',
  deeppink: 'ff1493',
  deepskyblue: '00bfff',
  dimgray: '696969',
  dodgerblue: '1e90ff',
  feldspar: 'd19275',
  firebrick: 'b22222',
  floralwhite: 'fffaf0',
  forestgreen: '228b22',
  fuchsia: 'ff00ff',
  gainsboro: 'dcdcdc',
  ghostwhite: 'f8f8ff',
  gold: 'ffd700',
  goldenrod: 'daa520',
  gray: '808080',
  green: '008000',
  greenyellow: 'adff2f',
  honeydew: 'f0fff0',
  hotpink: 'ff69b4',
  indianred: 'cd5c5c',
  indigo: '4b0082',
  ivory: 'fffff0',
  khaki: 'f0e68c',
  lavender: 'e6e6fa',
  lavenderblush: 'fff0f5',
  lawngreen: '7cfc00',
  lemonchiffon: 'fffacd',
  lightblue: 'add8e6',
  lightcoral: 'f08080',
  lightcyan: 'e0ffff',
  lightgoldenrodyellow: 'fafad2',
  lightgrey: 'd3d3d3',
  lightgreen: '90ee90',
  lightpink: 'ffb6c1',
  lightsalmon: 'ffa07a',
  lightseagreen: '20b2aa',
  lightskyblue: '87cefa',
  lightslateblue: '8470ff',
  lightslategray: '778899',
  lightsteelblue: 'b0c4de',
  lightyellow: 'ffffe0',
  lime: '00ff00',
  limegreen: '32cd32',
  linen: 'faf0e6',
  magenta: 'ff00ff',
  maroon: '800000',
  mediumaquamarine: '66cdaa',
  mediumblue: '0000cd',
  mediumorchid: 'ba55d3',
  mediumpurple: '9370d8',
  mediumseagreen: '3cb371',
  mediumslateblue: '7b68ee',
  mediumspringgreen: '00fa9a',
  mediumturquoise: '48d1cc',
  mediumvioletred: 'c71585',
  midnightblue: '191970',
  mintcream: 'f5fffa',
  mistyrose: 'ffe4e1',
  moccasin: 'ffe4b5',
  navajowhite: 'ffdead',
  navy: '000080',
  oldlace: 'fdf5e6',
  olive: '808000',
  olivedrab: '6b8e23',
  orange: 'ffa500',
  orangered: 'ff4500',
  orchid: 'da70d6',
  palegoldenrod: 'eee8aa',
  palegreen: '98fb98',
  paleturquoise: 'afeeee',
  palevioletred: 'd87093',
  papayawhip: 'ffefd5',
  peachpuff: 'ffdab9',
  peru: 'cd853f',
  pink: 'ffc0cb',
  plum: 'dda0dd',
  powderblue: 'b0e0e6',
  purple: '800080',
  red: 'ff0000',
  rosybrown: 'bc8f8f',
  royalblue: '4169e1',
  saddlebrown: '8b4513',
  salmon: 'fa8072',
  sandybrown: 'f4a460',
  seagreen: '2e8b57',
  seashell: 'fff5ee',
  sienna: 'a0522d',
  silver: 'c0c0c0',
  skyblue: '87ceeb',
  slateblue: '6a5acd',
  slategray: '708090',
  snow: 'fffafa',
  springgreen: '00ff7f',
  steelblue: '4682b4',
  tan: 'd2b48c',
  teal: '008080',
  thistle: 'd8bfd8',
  tomato: 'ff6347',
  turquoise: '40e0d0',
  violet: 'ee82ee',
  violetred: 'd02090',
  wheat: 'f5deb3',
  white: 'ffffff',
  whitesmoke: 'f5f5f5',
  yellow: 'ffff00',
  yellowgreen: '9acd32'
};

// array of color definition objects
const colorDefs = [
  {
    re: /^rgb\((?<r>\d{1,3}),\s*(?<g>\d{1,3}),\s*(?<b>\d{1,3})\)$/,
    example: ['rgb(123, 234, 45)', 'rgb(255,234,245)'],
    process (_, ...bits) {
      return bits.map((b) => parseInt(b));
    }
  },
  {
    re: /^(?<r>\w{2})(?<g>\w{2})(?<b>\w{2})$/,
    example: ['#00ff00', '336699'],
    process (_, ...bits) {
      return bits.map((b) => parseInt(b, 16));
    }
  },
  {
    re: /^(?<r>\w{1})(?<g>\w{1})(?<b>\w{1})$/,
    example: ['#fb0', 'f0f'],
    process (_, ...bits) {
      return bits.map((b) => parseInt(b + b, 16));
    }
  }
];

/**
 * A class to parse color values.
 */
export default class RGBColor {
  /**
  * @param {string} colorString
  */
  constructor (colorString) {
    this.ok = false;

    // strip any leading #
    if (colorString.charAt(0) === '#') { // remove # if any
      colorString = colorString.substr(1, 6);
    }

    colorString = colorString.replace(/ /g, '');
    colorString = colorString.toLowerCase();

    // before getting into regexps, try simple matches
    // and overwrite the input
    if (colorString in simpleColors) {
      colorString = simpleColors[colorString];
    }
    // end of simple type-in colors

    // search through the definitions to find a match

    colorDefs.forEach(({re, process: processor}) => {
      const bits = re.exec(colorString);
      if (bits) {
        const [r, g, b] = processor(...bits);
        Object.assign(this, {r, g, b});
        this.ok = true;
      }
    });

    // validate/cleanup values
    this.r = (this.r < 0 || isNaN(this.r)) ? 0 : ((this.r > 255) ? 255 : this.r);
    this.g = (this.g < 0 || isNaN(this.g)) ? 0 : ((this.g > 255) ? 255 : this.g);
    this.b = (this.b < 0 || isNaN(this.b)) ? 0 : ((this.b > 255) ? 255 : this.b);
  }

  // some getters
  /**
  * @returns {string}
  */
  toRGB () {
    return 'rgb(' + this.r + ', ' + this.g + ', ' + this.b + ')';
  }

  /**
  * @returns {string}
  */
  toHex () {
    let r = this.r.toString(16);
    let g = this.g.toString(16);
    let b = this.b.toString(16);
    if (r.length === 1) { r = '0' + r; }
    if (g.length === 1) { g = '0' + g; }
    if (b.length === 1) { b = '0' + b; }
    return '#' + r + g + b;
  }

  /**
  * Offers a bulleted list of help.
  * @returns {HTMLUListElement}
  */
  static getHelpXML () {
    const examples = [
      // add regexps
      ...colorDefs.flatMap(({example}) => {
        return example;
      }),
      // add type-in colors
      ...Object.keys(simpleColors)
    ];

    const xml = document.createElement('ul');
    xml.setAttribute('id', 'rgbcolor-examples');

    xml.append(...examples.map((example) => {
      try {
        const listItem = document.createElement('li');
        const listColor = new RGBColor(example);
        const exampleDiv = document.createElement('div');
        exampleDiv.style.cssText = `
  margin: 3px;
  border: 1px solid black;
  background: ${listColor.toHex()};
  color: ${listColor.toHex()};`;
        exampleDiv.append('test');
        const listItemValue = ` ${example} -> ${listColor.toRGB()} -> ${listColor.toHex()}`;
        listItem.append(exampleDiv, listItemValue);
        return listItem;
      } catch (e) {
        return '';
      }
    }));
    return xml;
  }
}