module.exports = class RegExpExtensions
  # http://stackoverflow.com/questions/201323/using-a-regular-expression-to-validate-an-email-address
  @escapeRegExp: (string) -> (string?.replace? /[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, "\\$&") ? ''


  @findUrlProtocolRegExp: /([\w-]+)(:\/\/)/
  @findDomainRegExp:      ///
    localhost
    | [\w]+(?:-[\w]+)*(?:\.[\w]+(?:-[\w]+)*)*(?:\.[a-z]{2,20})
    | \d+ \. \d+ \. \d+ \. \d+
    ///i

  @urlQueryParamsRegExp:  ///(?:[-+=&*._\w]|%[a-f\d]{2})* (?!\.) (?:[-+=&*._\w]|%[a-f\d]{2})///i

  # https://stackoverflow.com/questions/4669692/valid-characters-for-directory-part-of-a-url-for-short-links
  # https://tools.ietf.org/html/rfc3986#section-3.3
  @findLegalUrlCharacterRegExp: /// [-._~!$&'()*+,;=:@\w] | %[a-f\d]{2} ///
  @findUrlPathRegExp:     /// (?: \/ (?: (?: #{@findLegalUrlCharacterRegExp.source} ) * (?!\.) (?:#{@findLegalUrlCharacterRegExp.source}) )? ) * ///
  @findUrlPortRegExp:     /(\:)(\d+)/
  @findUrlFragmentRegExp: /// (\#) ( (?: (?: \? | #{@findLegalUrlCharacterRegExp.source} ) * (?!\.) #{@findLegalUrlCharacterRegExp.source} | ) ) ///

  ###
  https://tools.ietf.org/html/rfc3696
  terms: local@domain
  lengths:
    total:  320 max
    local:  64 max
    domain: 255 max
  2012 unicode update: https://tools.ietf.org/html/rfc6531
  Argued here - make a permissive test:
  https://news.ycombinator.com/item?id=9089129
  So, here is my permissive test:
    I want something that can reasonably extract emails from random text.
    no spaces unless escaped or quoted
    at least something before @
    support for quotes (") and escapes (\.)
    at least one non-space in domain
    only one '@'
    Domain must have at least one '.' after a character and before a character

  Minimum Example:
    a@a.a
  ###
  @findEmailLocalRegExp: ///
    (
      (?: [^:@<>\s\n"\\] | \\. )+
      |
      " (?: [^@"\\] | \\. )* "
    )
    ///

  @findEmailRegExp:       ///
    #{@findEmailLocalRegExp.source}
    @
    (
      [^@:?\s\n<>.]+
      \.
      [^@:?\s\n<>]*
      [^@:?\s\n<>.]
    )
    ///i

  @emailRegExp:           ///^#{@findEmailRegExp.source}$///i

  @numberRegExp:          /([-]?\.[0-9]+)|([-]?[0-9]+(\.[0-9]+)?)/

  @urlProtocolRegExp:     ///^#{@findUrlProtocolRegExp.source}$///i
  @domainRegExp:          ///^#{@findDomainRegExp.source}$///i
  @urlPathRegExp:         ///^#{@findUrlPathRegExp.source}$///i
  @urlQueryRegExp:        ///^#{@urlQueryParamsRegExp.source}$///i

  @isoDateRegExp:         /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W([0-4]\d|5[0-2])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[1-6])))([T\s]((([01]\d|2[0-3])((:?)[0-5]\d)?|24\:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$/

  @hex16GreyColorRegExp:  /^#([a-f0-9])$/i
  @hex256GreyColorRegExp: /^#([a-f0-9]{2})$/i
  @hex16ColorRegExp:      /^#([a-f0-9])([a-f0-9])([a-f0-9])([a-f0-9])?$/i
  @hex256ColorRegExp:     /^#([a-f0-9]{2})([a-f0-9]{2})([a-f0-9]{2})([a-f0-9]{2})?$/i
  @rgbColorRegExp:        /rgb *\( *(\d+%?) *, *(\d+%?) *, *(\d+%?) *\)/
  @rgbaColorRegExp:       /rgba *\( *(\d+%?) *, *(\d+%?) *, *(\d+%?) *, *(\d*\.?\d*)\)/

  @findColorRegExp:
    ///
    (#{@hex16GreyColorRegExp.source}) |
    (#{@hex256GreyColorRegExp.source}) |
    (#{@hex16ColorRegExp.source}) |
    (#{@hex256ColorRegExp.source}) |
    (#{@rgbColorRegExp.source}) |
    (#{@rgbaColorRegExp.source})
    ///i

  @colorRegExp: /// ^ #{@findColorRegExp.source} $ ///

  @wordsRegExp: /[^\s]+/g
  @exactlyOneWordRegExp: /^[^\s]+$/

  # protocol, domain and port
  @findUrlOrigin: ///
    (?:#{@findUrlProtocolRegExp.source})
    (#{@findDomainRegExp.source})?
    (?:#{@findUrlPortRegExp.source})?
    ///i

  ###
  match OUTPUT: [url, protocol, '://', domain, ':', port, path, '?', query]

  USAGE:
    [__, protocol, __, domain, __, port, path, __, query, __, fragment] = str.match findUrlRegExp

  DESIGN NOTE:
    The reason why I included the fixed strings ('://', ':' and '?') was so that
    you can take the matchResult, alter individual elements and create a value url easily by:

      matchResult.slice(1).join ''
  ###
  @findUrlRegExp:  ///
    #{@findUrlOrigin.source}
    (#{@findUrlPathRegExp.source})?
    (?:(\?)(#{@urlQueryParamsRegExp.source})?)?
    (?:#{@findUrlFragmentRegExp.source})?
    ///i

  @findUrlWithOptionalProtocolRegExp:  ///
    (?:#{@findUrlProtocolRegExp.source})?
    (#{@findDomainRegExp.source})
    (?:#{@findUrlPortRegExp.source})?
    (#{@findUrlPathRegExp.source})?
    (?:(\?)(#{@urlQueryParamsRegExp.source})?)?
    (?:#{@findUrlFragmentRegExp.source})?
    ///i

  @findAllUrlsRegExp: ///#{@findUrlRegExp.source}///ig

  @findAllUrlsWithOptionalProtocolRegExp:  ///#{@findUrlWithOptionalProtocolRegExp.source}///ig

  @findSourceReferenceUrlRegExp: ///
    #{@findUrlOrigin.source}
    (#{@findUrlPathRegExp.source})?
    (?:(\?)(#{@urlQueryParamsRegExp.source})?)?
    (?:\:(\d+))?
    (?:\:(\d+))?
    ///i

  # OUT: see findUrlRegExp
  @urlRegExp: ///^#{@findUrlRegExp.source}$///i

  # OUT: see findUrlRegExp
  @urlWithOptionalProtocolRegExp: ///^#{@findUrlWithOptionalProtocolRegExp.source}$///i

  # *Regexp names DEPRICATED
  # *Regex names - maybe DEPRICATED... ?
  for k, v of @ when /RegExp$/.test k
    @[k.replace /RegExp/, "Regexp"] = v
    @[k.replace /RegExp/, "Regex"] = v

  lc = (s) -> s.toLocaleLowerCase()
  @normalizeUrl: (url) =>
    url = if @findUrlProtocolRegExp.exec(url)?.index == 0
      url
    else
      "http://#{url}"

    url
    .replace @findDomainRegExp, lc
    .replace @findUrlProtocolRegExp, lc