/* Recommended usage
  16-bit colors:
    black
    darkblue
    green
    red
    brown
    purple
    gold
    yellow
    limegreen
    cyan
    lightblue
    blue
    pink
    darkgray
    gray
    white
  or any hex value prepended with #

  Formats:
    action
    code
    multicode (multiline code)
    bold
    italics
    emphasis
    strike
    underline
*/

import { thousandsSeparator, timeSince, toHHMMSS } from '../common';

// Color Utilities

export function colorDistance(s: string, t: string): number {
  if (!s.length || !t.length) {
    return 0;
  }

  return colorDistance(s.slice(2), t.slice(2)) +
      Math.abs(parseInt(s.slice(0, 2), 16) - parseInt(t.slice(0, 2), 16));
}

export function approximateB16Color(cl: string): string {
  const arr = [];
  let closest = 'white';

  for (const i in b16Colors) {
    arr.push(b16Colors[i].substring(1));
  }

  cl = cl.substring(1);

  arr.sort((a, b) => {
    return colorDistance(a, cl) - colorDistance(b, cl);
  });

  for (const i in b16Colors) {
    if (b16Colors[i] === '#' + arr[0]) {
      closest = i;
    }
  }

  return closest;
}

export function b16toHex(name: string): string {
  if (!b16Colors[name]) {
    return '#000000';
  }

  return b16Colors[name];
}

interface IMethod {
  start: string;
  end: string;
}

declare type Keyed = {[key: string]: string};
declare type Method = {[key: string]: IMethod};

const b16Colors: Keyed = {
  black: '#000000',
  darkblue: '#00007f',
  green: '#009300',
  red: '#ff0000',
  brown: '#7f0000',
  purple: '#9c009c',
  gold: '#fc7f00',
  yellow: '#ffff00',
  limegreen: '#00fc00',
  cyan: '#00ffff',
  lightblue: '#0000fc',
  blue: '#009393',
  pink: '#ff00ff',
  darkgray: '#7f7f7f',
  gray: '#d2d2d2',
  white: '#ffffff'
};

/**
 * Base class for message formatting
 */
export class Formatter {
  public colors: Keyed = {};
  public formatting: Method = {};
  public colorEscape = '';
  constructor(
    public supportFormatting = false,
    public supportColors = false
  ) {}

  public color(color: string, msg: string): string {
    return msg;
  }

  public format(method: string, msg: string): string {
    if (!this.supportFormatting) {
      return msg;
    }

    if (!this.formatting[method]) {
      return msg;
    }

    if (this.formatting[method].start && this.formatting[method].end) {
      return this.formatting[method].start + msg + this.formatting[method].end;
    } else {
      return this.formatting[method] + msg + this.formatting[method];
    }
  }

  public strip(msg: string): string {
    return msg;
  }

  // Object compositor.
  // This default function turns objects into plain text without any formatting.
  // Override this in your protocol for the desired effect.
  /*
    [
      ['element type', 'text', { param: value }],
      ...
    ]

    Element types:
      field - A field type
        Parameters:
          * label - Label for this field. If an array, the first item is considered an "icon" and wont have ':' appended to it.
          * type - The type of the field.
              title       - A title field
              description - Descriptive field
              metric      - A Number value. Requires integer, will be transformed into xxx,xxx,xxx
              time        - Time value. Requires UNIX timestamp.
              timesince   - Time since value. Requires UNIX timestamp, will be transformed into x seconds/minutes/hours/days ago
              duration    - Duration value. Requires integer, will be transformed into HH:MM:SS
              content     - Full message body.
          * color - The color of the field. Not always supported.
      bold/b/strong - Bold text
      i/italic - Italic text
      color - A colored text. Not always supported.
      url - An URL.
        Parameters:
          * label - Label for this URL
      image - An Image.
  */

  public compose(objs: any): any {
    const str = [];

    for (const i in objs) {
      const elem = objs[i];

      const elemType = elem[0];
      let elemValue = elem[1];
      const elemParams = elem[2];

      if (!elemValue) {
        continue;
      }

      // Special types
      if (elemParams && elemParams.type) {
        switch (elemParams.type) {
        case 'time':
          elemValue = new Date(elemValue).toString();
          break;
        case 'metric':
          elemValue = thousandsSeparator(elemValue);
          break;
        case 'timesince':
          elemValue = timeSince(elemValue);
          break;
        case 'duration':
          elemValue = toHHMMSS(elemValue);
          break;
        }
      }

      if (elemParams && elemParams.label) {
        let label = elemParams.label;

        // If the label param is an array, choose the last element
        // The last element is generally the text version, as opposed to
        // the first element being an icon.
        if (typeof label === 'object') {
          label = elemParams.label[elemParams.label.length - 1];
        }

        str.push(elemParams.label + ': ' + elemValue);
      } else {
        str.push(elemValue);
      }
    }

    // May return an object, but your protocol must support it.
    return str.join(' ');
  }
}

/**
 * Built-in formatter for HTML-enabled protocols
 */
export class HTMLFormatter extends Formatter {
  public formatting: Method = {
    code: {start: '<code>', end: '</code>'},
    action: {start: '<i>', end: '</i>'},
    bold: {start: '<b>', end: '</b>'},
    italics: {start: '<i>', end: '</i>'},
    emphasis: {start: '<em>', end: '</em>'},
    underline: {start: '<u>', end: '</u>'},
    multicode: {start: '<pre><code>', end: '</code></pre>'},
  };

  constructor() {
    super(true, true);
  }

  public color(color: string, msg: string): string {
    return `<span style="color:${color};">${msg}</span>`;
  }

  public format(method: string, msg: string): string {
    if (!this.formatting[method]) {
      return msg;
    }

    if (this.formatting[method].start && this.formatting[method].end) {
      return this.formatting[method].start + msg + this.formatting[method].end;
    } else {
      return this.formatting[method] + msg + this.formatting[method];
    }
  }

  public strip(msg: string): string {
    return msg.replace(/<\/?[^>]+(>|$)/g, '');
  }
}

/**
 * Built-in formatter for Markdown-enabled protocols
 */
export class MarkdownFormatter extends Formatter {
  public formatting: Method = {
    code: {start: '`', end: '`'},
    bold: {start: '**', end: '**'},
    action: {start: '*', end: '*'},
    italics: {start: '*', end: '*'},
    emphasis: {start: '*', end: '*'},
    underline: {start: '__', end: '__'},
    multicode: {start: '```', end: '```'},
  };

  constructor() {
    super(true, false);
  }

  public color(color: string, msg: string): string {
    return msg;
  }

  public format(method: string, msg: string): string {
    if (!this.formatting[method]) {
      return msg;
    }

    if (this.formatting[method].start && this.formatting[method].end) {
      return this.formatting[method].start + msg + this.formatting[method].end;
    } else {
      return this.formatting[method] + msg + this.formatting[method];
    }
  }

  public strip(msg: string): string {
    return msg;
  }
}