class MynaBird

  class MalformedEmailException < Exception
  end

  COMMON_LOCALS = %w(
    support info sales marketing admin webmaster help
  )

  COMMON_DOMAINS = %w(
    hotmail msn live yahoo yahoo.co.uk ymail rocketmail gmail googlemail aol
    fastmail.fm web inbox freemail rediff indiatimes lycos libero.it rambler.ru mac
    paracalls linkedin mynet interia.pl yandex sina 126 lycos bol in me
    voila.fr mail comcast netcom roadrunner verizon 1and1 att adelphia
    bigpond bluebottle blueyonder btopenworld charter cox earthlink sbc telus
    mailinator charter rogers sympatico tiscali tmail sbcglobal aim windowslive
    juno qq optonline.net mailhaven.com shaw.ca btinternet email orange.fr
    frontier.com outlook icloud reliable-mail
  ) + [
    /\.edu$/
  ]

  def self.convert(email)
    new(email).name
  end

  def initialize(email)
    # email must be in a somewhat sane format
    # i.e. have an @ sign and at least one letter or number on each side of it
    raise MalformedEmailException unless email =~ /^[^@]*[a-z0-9][^@]*@[^@]*[a-z0-9][^@]*$/i

    @email = email.downcase
    @local, @domain = @email.split('@')
  end


  # extract the name
  def name
    if common_local? && common_domain?
      local_name + '-at-' + domain_name
    elsif common_local?
      domain_name
    elsif common_domain?
      local_name
    else
      domain_name
    end
  end

  def domain_name
    just_the_host = @domain.split('.').first
    self.class.nameize(just_the_host)
  end

  def local_name
    local_sans_alias = @local.gsub(/\+.*$/, '')
    self.class.nameize(local_sans_alias)
  end

  def self.nameize(str)
    name = str.downcase
    name.gsub!(/[^a-z0-9]+/, '-')
    name.gsub!(/\-$/,'')
    name.gsub!(/^\-/,'')
    name
  end

  def common_domain?
    COMMON_DOMAINS.each do |domain|
      if domain.is_a?(Regexp)
        return true if domain.match(@domain)
      elsif domain =~ /\./
        return true if /#{domain}$/.match(@domain)
      else
        return true if /^#{domain}\./.match(@domain)
      end
    end

    return false
  end

  def common_local?
    COMMON_LOCALS.each do |local|
      if local.is_a?(Regexp)
        return true if local.match(@local)
      else
        return true if local == @local
      end
    end

    return false
  end

end