// Source & more langs: https://gist.github.com/sgmurphy/3095196

/* eslint-disable object-property-newline */
const char_map = {
  // Latin
  'À': 'A', 'Á': 'A', 'Â': 'A', 'Ã': 'A', 'Ä': 'A', 'Å': 'A', 'Æ': 'AE', 'Ç': 'C',
  'È': 'E', 'É': 'E', 'Ê': 'E', 'Ë': 'E', 'Ì': 'I', 'Í': 'I', 'Î': 'I', 'Ï': 'I',
  'Ð': 'D', 'Ñ': 'N', 'Ò': 'O', 'Ó': 'O', 'Ô': 'O', 'Õ': 'O', 'Ö': 'O', 'Ő': 'O',
  'Ø': 'O', 'Ù': 'U', 'Ú': 'U', 'Û': 'U', 'Ü': 'U', 'Ű': 'U', 'Ý': 'Y', 'Þ': 'TH',
  'ß': 'ss',
  'à': 'a', 'á': 'a', 'â': 'a', 'ã': 'a', 'ä': 'a', 'å': 'a', 'æ': 'ae', 'ç': 'c',
  'è': 'e', 'é': 'e', 'ê': 'e', 'ë': 'e', 'ì': 'i', 'í': 'i', 'î': 'i', 'ï': 'i',
  'ð': 'd', 'ñ': 'n', 'ò': 'o', 'ó': 'o', 'ô': 'o', 'õ': 'o', 'ö': 'o', 'ő': 'o',
  'ø': 'o', 'ù': 'u', 'ú': 'u', 'û': 'u', 'ü': 'u', 'ű': 'u', 'ý': 'y', 'þ': 'th',
  'ÿ': 'y',

  // Latin symbols
  '©': '(c)',

  // Czech
  'Č': 'C', 'Ď': 'D', 'Ě': 'E', 'Ň': 'N', 'Ř': 'R', 'Š': 'S', 'Ť': 'T', 'Ů': 'U',
  'Ž': 'Z',
  'č': 'c', 'ď': 'd', 'ě': 'e', 'ň': 'n', 'ř': 'r', 'š': 's', 'ť': 't', 'ů': 'u',
  'ž': 'z',

  // Polish
  'Ą': 'A', 'Ć': 'C', 'Ę': 'e', 'Ł': 'L', 'Ń': 'N', 'Ś': 'S', 'Ź': 'Z',
  'Ż': 'Z',
  'ą': 'a', 'ć': 'c', 'ę': 'e', 'ł': 'l', 'ń': 'n', 'ś': 's', 'ź': 'z',
  'ż': 'z'
}
/* eslint-enable object-property-newline */

const alnum = new RegExp('[^a-z0-9]+', 'ig')

/**
 * Create a web friendly URL slug from a string.
 *
 * Although supported, transliteration is discouraged because
 *     1) most web browsers support UTF-8 characters in URLs
 *     2) transliteration causes a loss of information
 *
 * @author Sean Murphy <sean@iamseanmurphy.com>
 * @copyright Copyright 2012 Sean Murphy. All rights reserved.
 * @license http://creativecommons.org/publicdomain/zero/1.0/
 *
 * @return string
 * @param {string} s
 * @param {object} opt
 */
function url_slug (s, opt) {
  let k

  s = String(s)
  opt = Object(opt)

  const defaults = {
    'delimiter': '-',
    'limit': undefined,
    'lowercase': true,
    'replacements': {},
    'transliterate': true
  }

  // Merge options
  for (k in defaults) {
    if (defaults.hasOwnProperty(k) && !opt.hasOwnProperty(k)) {
      opt[k] = defaults[k]
    }
  }

  // Make custom replacements
  for (k in opt.replacements) {
    if (opt.replacements.hasOwnProperty(k)) {
      s = s.replace(new RegExp(k, 'g'), opt.replacements[k])
    }
  }

  // Transliterate characters to ASCII
  if (opt.transliterate) {
    for (k in char_map) {
      if (char_map.hasOwnProperty(k)) {
        s = s.replace(new RegExp(k, 'g'), char_map[k])
      }
    }
  }

  // Replace non-alphanumeric characters with our delimiter
  s = s.replace(alnum, opt.delimiter)

  // Remove duplicate delimiters
  s = s.replace(new RegExp('[' + opt.delimiter + ']{2,}', 'g'), opt.delimiter)

  // Truncate slug to max. characters
  s = s.substring(0, opt.limit)

  // Remove delimiter from ends
  s = s.replace(new RegExp('(^' + opt.delimiter + '|' + opt.delimiter + '$)', 'g'), '')

  return opt.lowercase ? s.toLowerCase() : s
}

module.exports = url_slug