/* ---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/
// Some code copied and modified from https://github.com/microsoft/vscode/blob/1.44.0/src/vs/base/common/color.ts

import { CharCode } from '@opensumi/ide-core-common';

function roundFloat(num: number, decimalPoints: number): number {
  const decimal = Math.pow(10, decimalPoints);
  return Math.round(num * decimal) / decimal;
}

export class RGBA {
  _rgbaBrand: void;

  /**
   * Red: integer in [0-255]
   */
  readonly r: number;

  /**
   * Green: integer in [0-255]
   */
  readonly g: number;

  /**
   * Blue: integer in [0-255]
   */
  readonly b: number;

  /**
   * Alpha: float in [0-1]
   */
  readonly a: number;

  constructor(r: number, g: number, b: number, a = 1) {
    this.r = Math.min(255, Math.max(0, r)) | 0;
    this.g = Math.min(255, Math.max(0, g)) | 0;
    this.b = Math.min(255, Math.max(0, b)) | 0;
    this.a = roundFloat(Math.max(Math.min(1, a), 0), 3);
  }

  static equals(a: RGBA, b: RGBA): boolean {
    return a.r === b.r && a.g === b.g && a.b === b.b && a.a === b.a;
  }
}

export class HSLA {
  _hslaBrand: void;

  /**
   * Hue: integer in [0, 360]
   */
  readonly h: number;

  /**
   * Saturation: float in [0, 1]
   */
  readonly s: number;

  /**
   * Luminosity: float in [0, 1]
   */
  readonly l: number;

  /**
   * Alpha: float in [0, 1]
   */
  readonly a: number;

  constructor(h: number, s: number, l: number, a: number) {
    this.h = Math.max(Math.min(360, h), 0) | 0;
    this.s = roundFloat(Math.max(Math.min(1, s), 0), 3);
    this.l = roundFloat(Math.max(Math.min(1, l), 0), 3);
    this.a = roundFloat(Math.max(Math.min(1, a), 0), 3);
  }

  static equals(a: HSLA, b: HSLA): boolean {
    return a.h === b.h && a.s === b.s && a.l === b.l && a.a === b.a;
  }

  /**
   * Converts an RGB color value to HSL. Conversion formula
   * adapted from http://en.wikipedia.org/wiki/HSL_color_space.
   * Assumes r, g, and b are contained in the set [0, 255] and
   * returns h in the set [0, 360], s, and l in the set [0, 1].
   */
  static fromRGBA(rgba: RGBA): HSLA {
    const r = rgba.r / 255;
    const g = rgba.g / 255;
    const b = rgba.b / 255;
    const a = rgba.a;

    const max = Math.max(r, g, b);
    const min = Math.min(r, g, b);
    let h = 0;
    let s = 0;
    const l = (min + max) / 2;
    const chroma = max - min;

    if (chroma > 0) {
      s = Math.min(l <= 0.5 ? chroma / (2 * l) : chroma / (2 - 2 * l), 1);

      switch (max) {
        case r:
          h = (g - b) / chroma + (g < b ? 6 : 0);
          break;
        case g:
          h = (b - r) / chroma + 2;
          break;
        case b:
          h = (r - g) / chroma + 4;
          break;
      }

      h *= 60;
      h = Math.round(h);
    }
    return new HSLA(h, s, l, a);
  }

  private static _hue2rgb(p: number, q: number, t: number): number {
    if (t < 0) {
      t += 1;
    }
    if (t > 1) {
      t -= 1;
    }
    if (t < 1 / 6) {
      return p + (q - p) * 6 * t;
    }
    if (t < 1 / 2) {
      return q;
    }
    if (t < 2 / 3) {
      return p + (q - p) * (2 / 3 - t) * 6;
    }
    return p;
  }

  /**
   * Converts an HSL color value to RGB. Conversion formula
   * adapted from http://en.wikipedia.org/wiki/HSL_color_space.
   * Assumes h in the set [0, 360] s, and l are contained in the set [0, 1] and
   * returns r, g, and b in the set [0, 255].
   */
  static toRGBA(hsla: HSLA): RGBA {
    const h = hsla.h / 360;
    const { s, l, a } = hsla;
    let r: number;
    let g: number;
    let b: number;

    if (s === 0) {
      r = g = b = l; // achromatic
    } else {
      const q = l < 0.5 ? l * (1 + s) : l + s - l * s;
      const p = 2 * l - q;
      r = HSLA._hue2rgb(p, q, h + 1 / 3);
      g = HSLA._hue2rgb(p, q, h);
      b = HSLA._hue2rgb(p, q, h - 1 / 3);
    }

    return new RGBA(Math.round(r * 255), Math.round(g * 255), Math.round(b * 255), a);
  }
}

export class HSVA {
  _hsvaBrand: void;

  /**
   * Hue: integer in [0, 360]
   */
  readonly h: number;

  /**
   * Saturation: float in [0, 1]
   */
  readonly s: number;

  /**
   * Value: float in [0, 1]
   */
  readonly v: number;

  /**
   * Alpha: float in [0, 1]
   */
  readonly a: number;

  constructor(h: number, s: number, v: number, a: number) {
    this.h = Math.max(Math.min(360, h), 0) | 0;
    this.s = roundFloat(Math.max(Math.min(1, s), 0), 3);
    this.v = roundFloat(Math.max(Math.min(1, v), 0), 3);
    this.a = roundFloat(Math.max(Math.min(1, a), 0), 3);
  }

  static equals(a: HSVA, b: HSVA): boolean {
    return a.h === b.h && a.s === b.s && a.v === b.v && a.a === b.a;
  }

  // from http://www.rapidtables.com/convert/color/rgb-to-hsv.htm
  static fromRGBA(rgba: RGBA): HSVA {
    const r = rgba.r / 255;
    const g = rgba.g / 255;
    const b = rgba.b / 255;
    const cmax = Math.max(r, g, b);
    const cmin = Math.min(r, g, b);
    const delta = cmax - cmin;
    const s = cmax === 0 ? 0 : delta / cmax;
    let m: number;

    if (delta === 0) {
      m = 0;
    } else if (cmax === r) {
      m = ((((g - b) / delta) % 6) + 6) % 6;
    } else if (cmax === g) {
      m = (b - r) / delta + 2;
    } else {
      m = (r - g) / delta + 4;
    }

    return new HSVA(Math.round(m * 60), s, cmax, rgba.a);
  }

  // from http://www.rapidtables.com/convert/color/hsv-to-rgb.htm
  static toRGBA(hsva: HSVA): RGBA {
    const { h, s, v, a } = hsva;
    const c = v * s;
    const x = c * (1 - Math.abs(((h / 60) % 2) - 1));
    const m = v - c;
    let [r, g, b] = [0, 0, 0];

    if (h < 60) {
      r = c;
      g = x;
    } else if (h < 120) {
      r = x;
      g = c;
    } else if (h < 180) {
      g = c;
      b = x;
    } else if (h < 240) {
      g = x;
      b = c;
    } else if (h < 300) {
      r = x;
      b = c;
    } else if (h < 360) {
      r = c;
      b = x;
    }

    r = Math.round((r + m) * 255);
    g = Math.round((g + m) * 255);
    b = Math.round((b + m) * 255);

    return new RGBA(r, g, b, a);
  }
}

export class Color {
  static fromHex(hex: string): Color {
    return Color.Format.CSS.parseHex(hex) || Color.red;
  }

  readonly rgba: RGBA;
  private _hsla?: HSLA;
  get hsla(): HSLA {
    if (this._hsla) {
      return this._hsla;
    } else {
      return HSLA.fromRGBA(this.rgba);
    }
  }

  private _hsva?: HSVA;
  get hsva(): HSVA {
    if (this._hsva) {
      return this._hsva;
    }
    return HSVA.fromRGBA(this.rgba);
  }

  constructor(arg: RGBA | HSLA | HSVA) {
    if (!arg) {
      throw new Error('Color needs a value');
    } else if (arg instanceof RGBA) {
      this.rgba = arg;
    } else if (arg instanceof HSLA) {
      this._hsla = arg;
      this.rgba = HSLA.toRGBA(arg);
    } else if (arg instanceof HSVA) {
      this._hsva = arg;
      this.rgba = HSVA.toRGBA(arg);
    } else {
      throw new Error('Invalid color ctor argument');
    }
  }

  equals(other: Color): boolean {
    return (
      !!other &&
      RGBA.equals(this.rgba, other.rgba) &&
      HSLA.equals(this.hsla, other.hsla) &&
      HSVA.equals(this.hsva, other.hsva)
    );
  }

  /**
   * http://www.w3.org/TR/WCAG20/#relativeluminancedef
   * Returns the number in the set [0, 1]. O => Darkest Black. 1 => Lightest white.
   */
  getRelativeLuminance(): number {
    const R = Color._relativeLuminanceForComponent(this.rgba.r);
    const G = Color._relativeLuminanceForComponent(this.rgba.g);
    const B = Color._relativeLuminanceForComponent(this.rgba.b);
    const luminance = 0.2126 * R + 0.7152 * G + 0.0722 * B;

    return roundFloat(luminance, 4);
  }

  private static _relativeLuminanceForComponent(color: number): number {
    const c = color / 255;
    return c <= 0.03928 ? c / 12.92 : Math.pow((c + 0.055) / 1.055, 2.4);
  }

  /**
   * http://www.w3.org/TR/WCAG20/#contrast-ratiodef
   * Returns the contrast ration number in the set [1, 21].
   */
  getContrastRatio(another: Color): number {
    const lum1 = this.getRelativeLuminance();
    const lum2 = another.getRelativeLuminance();
    return lum1 > lum2 ? (lum1 + 0.05) / (lum2 + 0.05) : (lum2 + 0.05) / (lum1 + 0.05);
  }

  /**
   *	http://24ways.org/2010/calculating-color-contrast
   *  Return 'true' if darker color otherwise 'false'
   */
  isDarker(): boolean {
    const yiq = (this.rgba.r * 299 + this.rgba.g * 587 + this.rgba.b * 114) / 1000;
    return yiq < 128;
  }

  /**
   *	http://24ways.org/2010/calculating-color-contrast
   *  Return 'true' if lighter color otherwise 'false'
   */
  isLighter(): boolean {
    const yiq = (this.rgba.r * 299 + this.rgba.g * 587 + this.rgba.b * 114) / 1000;
    return yiq >= 128;
  }

  isLighterThan(another: Color): boolean {
    const lum1 = this.getRelativeLuminance();
    const lum2 = another.getRelativeLuminance();
    return lum1 > lum2;
  }

  isDarkerThan(another: Color): boolean {
    const lum1 = this.getRelativeLuminance();
    const lum2 = another.getRelativeLuminance();
    return lum1 < lum2;
  }

  lighten(factor: number): Color {
    return new Color(new HSLA(this.hsla.h, this.hsla.s, this.hsla.l + this.hsla.l * factor, this.hsla.a));
  }

  darken(factor: number): Color {
    return new Color(new HSLA(this.hsla.h, this.hsla.s, this.hsla.l - this.hsla.l * factor, this.hsla.a));
  }

  transparent(factor: number): Color {
    const { r, g, b, a } = this.rgba;
    return new Color(new RGBA(r, g, b, a * factor));
  }

  isTransparent(): boolean {
    return this.rgba.a === 0;
  }

  isOpaque(): boolean {
    return this.rgba.a === 1;
  }

  opposite(): Color {
    return new Color(new RGBA(255 - this.rgba.r, 255 - this.rgba.g, 255 - this.rgba.b, this.rgba.a));
  }

  blend(c: Color): Color {
    const rgba = c.rgba;

    // Convert to 0..1 opacity
    const thisA = this.rgba.a;
    const colorA = rgba.a;

    const a = thisA + colorA * (1 - thisA);
    if (a < 1e-6) {
      return Color.transparent;
    }

    const r = (this.rgba.r * thisA) / a + (rgba.r * colorA * (1 - thisA)) / a;
    const g = (this.rgba.g * thisA) / a + (rgba.g * colorA * (1 - thisA)) / a;
    const b = (this.rgba.b * thisA) / a + (rgba.b * colorA * (1 - thisA)) / a;

    return new Color(new RGBA(r, g, b, a));
  }

  makeOpaque(opaqueBackground: Color): Color {
    if (this.isOpaque() || opaqueBackground.rgba.a !== 1) {
      // only allow to blend onto a non-opaque color onto a opaque color
      return this;
    }

    const { r, g, b, a } = this.rgba;

    // https://stackoverflow.com/questions/12228548/finding-equivalent-color-with-opacity
    return new Color(
      new RGBA(
        opaqueBackground.rgba.r - a * (opaqueBackground.rgba.r - r),
        opaqueBackground.rgba.g - a * (opaqueBackground.rgba.g - g),
        opaqueBackground.rgba.b - a * (opaqueBackground.rgba.b - b),
        1,
      ),
    );
  }

  flatten(...backgrounds: Color[]): Color {
    const background = backgrounds.reduceRight((accumulator, color) => Color._flatten(color, accumulator));
    return Color._flatten(this, background);
  }

  private static _flatten(foreground: Color, background: Color) {
    const backgroundAlpha = 1 - foreground.rgba.a;
    return new Color(
      new RGBA(
        backgroundAlpha * background.rgba.r + foreground.rgba.a * foreground.rgba.r,
        backgroundAlpha * background.rgba.g + foreground.rgba.a * foreground.rgba.g,
        backgroundAlpha * background.rgba.b + foreground.rgba.a * foreground.rgba.b,
      ),
    );
  }

  toString(): string {
    return '' + Color.Format.CSS.format(this);
  }

  static getLighterColor(of: Color, relative: Color, factor?: number): Color {
    if (of.isLighterThan(relative)) {
      return of;
    }
    factor = factor ? factor : 0.5;
    const lum1 = of.getRelativeLuminance();
    const lum2 = relative.getRelativeLuminance();
    factor = (factor * (lum2 - lum1)) / lum2;
    return of.lighten(factor);
  }

  static getDarkerColor(of: Color, relative: Color, factor?: number): Color {
    if (of.isDarkerThan(relative)) {
      return of;
    }
    factor = factor ? factor : 0.5;
    const lum1 = of.getRelativeLuminance();
    const lum2 = relative.getRelativeLuminance();
    factor = (factor * (lum1 - lum2)) / lum1;
    return of.darken(factor);
  }

  static readonly white = new Color(new RGBA(255, 255, 255, 1));
  static readonly black = new Color(new RGBA(0, 0, 0, 1));
  static readonly red = new Color(new RGBA(255, 0, 0, 1));
  static readonly blue = new Color(new RGBA(0, 0, 255, 1));
  static readonly green = new Color(new RGBA(0, 255, 0, 1));
  static readonly cyan = new Color(new RGBA(0, 255, 255, 1));
  static readonly lightgrey = new Color(new RGBA(211, 211, 211, 1));
  static readonly transparent = new Color(new RGBA(0, 0, 0, 0));
}

export namespace Color {
  export namespace Format {
    export namespace CSS {
      export function formatRGB(color: Color): string {
        if (color.rgba.a === 1) {
          return `rgb(${color.rgba.r}, ${color.rgba.g}, ${color.rgba.b})`;
        }

        return Color.Format.CSS.formatRGBA(color);
      }

      export function formatRGBA(color: Color): string {
        return `rgba(${color.rgba.r}, ${color.rgba.g}, ${color.rgba.b}, ${+color.rgba.a.toFixed(2)})`;
      }

      export function formatHSL(color: Color): string {
        if (color.hsla.a === 1) {
          return `hsl(${color.hsla.h}, ${(color.hsla.s * 100).toFixed(2)}%, ${(color.hsla.l * 100).toFixed(2)}%)`;
        }

        return Color.Format.CSS.formatHSLA(color);
      }

      export function formatHSLA(color: Color): string {
        return `hsla(${color.hsla.h}, ${(color.hsla.s * 100).toFixed(2)}%, ${(color.hsla.l * 100).toFixed(
          2,
        )}%, ${color.hsla.a.toFixed(2)})`;
      }

      function _toTwoDigitHex(n: number): string {
        const r = n.toString(16);
        return r.length !== 2 ? '0' + r : r;
      }

      /**
       * Formats the color as #RRGGBB
       */
      export function formatHex(color: Color): string {
        return `#${_toTwoDigitHex(color.rgba.r)}${_toTwoDigitHex(color.rgba.g)}${_toTwoDigitHex(color.rgba.b)}`;
      }

      /**
       * Formats the color as #RRGGBBAA
       * If 'compact' is set, colors without transparency will be printed as #RRGGBB
       */
      export function formatHexA(color: Color, compact = false): string {
        if (compact && color.rgba.a === 1) {
          return Color.Format.CSS.formatHex(color);
        }

        return `#${_toTwoDigitHex(color.rgba.r)}${_toTwoDigitHex(color.rgba.g)}${_toTwoDigitHex(
          color.rgba.b,
        )}${_toTwoDigitHex(Math.round(color.rgba.a * 255))}`;
      }

      /**
       * The default format will use HEX if opaque and RGBA otherwise.
       */
      export function format(color: Color): string | null {
        if (!color) {
          return null;
        }

        if (color.isOpaque()) {
          return Color.Format.CSS.formatHex(color);
        }

        return Color.Format.CSS.formatRGBA(color);
      }

      /**
       * Converts an Hex color value to a Color.
       * returns r, g, and b are contained in the set [0, 255]
       * @param hex string (#RGB, #RGBA, #RRGGBB or #RRGGBBAA).
       */
      export function parseHex(hex: string): Color | null {
        if (!hex) {
          // Invalid color
          return null;
        }

        const length = hex.length;

        if (length === 0) {
          // Invalid color
          return null;
        }

        if (hex.charCodeAt(0) !== CharCode.Hash) {
          // Does not begin with a #
          return null;
        }

        if (length === 7) {
          // #RRGGBB format
          const r = 16 * _parseHexDigit(hex.charCodeAt(1)) + _parseHexDigit(hex.charCodeAt(2));
          const g = 16 * _parseHexDigit(hex.charCodeAt(3)) + _parseHexDigit(hex.charCodeAt(4));
          const b = 16 * _parseHexDigit(hex.charCodeAt(5)) + _parseHexDigit(hex.charCodeAt(6));
          return new Color(new RGBA(r, g, b, 1));
        }

        if (length === 9) {
          // #RRGGBBAA format
          const r = 16 * _parseHexDigit(hex.charCodeAt(1)) + _parseHexDigit(hex.charCodeAt(2));
          const g = 16 * _parseHexDigit(hex.charCodeAt(3)) + _parseHexDigit(hex.charCodeAt(4));
          const b = 16 * _parseHexDigit(hex.charCodeAt(5)) + _parseHexDigit(hex.charCodeAt(6));
          const a = 16 * _parseHexDigit(hex.charCodeAt(7)) + _parseHexDigit(hex.charCodeAt(8));
          return new Color(new RGBA(r, g, b, a / 255));
        }

        if (length === 4) {
          // #RGB format
          const r = _parseHexDigit(hex.charCodeAt(1));
          const g = _parseHexDigit(hex.charCodeAt(2));
          const b = _parseHexDigit(hex.charCodeAt(3));
          return new Color(new RGBA(16 * r + r, 16 * g + g, 16 * b + b));
        }

        if (length === 5) {
          // #RGBA format
          const r = _parseHexDigit(hex.charCodeAt(1));
          const g = _parseHexDigit(hex.charCodeAt(2));
          const b = _parseHexDigit(hex.charCodeAt(3));
          const a = _parseHexDigit(hex.charCodeAt(4));
          return new Color(new RGBA(16 * r + r, 16 * g + g, 16 * b + b, (16 * a + a) / 255));
        }

        // Invalid color
        return null;
      }

      function _parseHexDigit(charCode: CharCode): number {
        switch (charCode) {
          case CharCode.Digit0:
            return 0;
          case CharCode.Digit1:
            return 1;
          case CharCode.Digit2:
            return 2;
          case CharCode.Digit3:
            return 3;
          case CharCode.Digit4:
            return 4;
          case CharCode.Digit5:
            return 5;
          case CharCode.Digit6:
            return 6;
          case CharCode.Digit7:
            return 7;
          case CharCode.Digit8:
            return 8;
          case CharCode.Digit9:
            return 9;
          case CharCode.a:
            return 10;
          case CharCode.A:
            return 10;
          case CharCode.b:
            return 11;
          case CharCode.B:
            return 11;
          case CharCode.c:
            return 12;
          case CharCode.C:
            return 12;
          case CharCode.d:
            return 13;
          case CharCode.D:
            return 13;
          case CharCode.e:
            return 14;
          case CharCode.E:
            return 14;
          case CharCode.f:
            return 15;
          case CharCode.F:
            return 15;
        }
        return 0;
      }
    }
  }
}
