'use strict';

const internals = {
  kCircularString: '[Circular]',
  kAnsiCodes: {
    bold: '[1m',
    italics: '[3m',
    underline: '[4m',
    inverse: '[7m',
    strikethrough: '[9m',
    bold_off: '[22m',
    italics_off: '[23m',
    underline_off: '[24m',
    inverse_off: '[27m',
    strikethrough_off: '[29m',
    black: '[30m',
    red: '[31m',
    green: '[32m',
    yellow: '[33m',
    blue: '[34m',
    magenta: '[35m',
    cyan: '[36m',
    white: '[37m',
    default: '[39m',
    black_bg: '[40m',
    red_bg: '[41m',
    green_bg: '[42m',
    yellow_bg: '[43m',
    blue_bg: '[44m',
    magenta_bg: '[45m',
    cyan_bg: '[46m',
    white_bg: '[47m',
    default_bg: '[49m',
    reset: '[0m'
  },

  // Get High Res time depending on platform. Currently only supporting node.

  getHighResTime() {

    return process.hrtime.bigint();
  }
};

// Initialise relative time.

internals.initialTimestamp = BigInt(Date.now()) * 1000000n;
internals.initialHighResTime = internals.getHighResTime();

/**
 * Container object for utilities used by loggers.
 *
 * @class Utilities
 */
module.exports = {

  /**
   * Returns the current timestamp in nanoseconds as a bigint.
   *
   * @function now
   * @memberof Utilities
   * @return {bigint} current time in nanoseconds, including fractions.
   */
  now() {

    return internals.initialTimestamp + internals.getHighResTime() - internals.initialHighResTime;
  },

  /**
   * Stringifies objects, avoiding circular references.
   *
   * @function stringify
   * @memberof Utilities
   * @param {Object} object the object to stringify
   * @return {String} the stringified object
   */
  stringify(object) {

    const cache = new Set();

    return JSON.stringify(object, (key, value) => {

      if (typeof value === 'bigint') {
        return String(value) + 'n';
      }

      if (typeof value === 'object' && value !== null) {
        if (cache.has(value)) {
          return internals.kCircularString;
        }

        cache.add(value);
      }

      return value;
    });
  },

  /**
   * Given an ansi keyword, it will return the appropriate code.
   *
   * @function getAnsiCode
   * @memberof Utilities
   * @param {String} ansiString the name of the desired code
   * @return {String} the ansi code
   */
  getAnsiCode(ansiString) {

    return internals.kAnsiCodes[ansiString] || internals.kAnsiCodes.reset;
  },

  /**
   * Given a level, it will return the appropriate ansi keyword related
   * to it.
   *
   * @function getLevelAnsi
   * @memberof Utilities
   * @param {number} level the level of the log
   * @return {String} the ansi keyword
   */
  getLevelAnsi(level) {

    switch (level) {
    case 0:
    case 1:
    case 2:
    case 3:
      return 'red';
    case 4:
      return 'yellow';
    case 5:
    case 6:
      return 'blue';
    case 7:
      return 'green';
    default:
      return 'default';
    }
  }
};