'use strict';

const internals = {
  kCircularString: '[Circular]',

  // 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) {

    switch (ansiString) {
    case 'bold':
      return '[1m';
    case 'italics':
      return '[3m';
    case 'underline':
      return '[4m';
    case 'inverse':
      return '[7m';
    case 'strikethrough':
      return '[9m';
    case 'bold_off':
      return '[22m';
    case 'italics_off':
      return '[23m';
    case 'underline_off':
      return '[24m';
    case 'inverse_off':
      return '[27m';
    case 'strikethrough_off':
      return '[29m';
    case 'black':
      return '[30m';
    case 'red':
      return '[31m';
    case 'green':
      return '[32m';
    case 'yellow':
      return '[33m';
    case 'blue':
      return '[34m';
    case 'magenta':
      return '[35m';
    case 'cyan':
      return '[36m';
    case 'white':
      return '[37m';
    case 'default':
      return '[39m';
    case 'black_bg':
      return '[40m';
    case 'red_bg':
      return '[41m';
    case 'green_bg':
      return '[42m';
    case 'yellow_bg':
      return '[43m';
    case 'blue_bg':
      return '[44m';
    case 'magenta_bg':
      return '[45m';
    case 'cyan_bg':
      return '[46m';
    case 'white_bg':
      return '[47m';
    case 'default_bg':
      return '[49m';
    case 'reset': // for informative purpouses
    default:
      return '[0m';
    }
  },

  /**
   * 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';
    }
  }
};