require 'localized_each_validator'

# Validates email addresses. Uses the `invalid_email` error message key.
#
# @example
#   validates :email_address, email: true
#
# Options
# -------
#
# |              |                                                                                                                                                                                                                                                                     |
# |:-------------|:--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
# | `:format`    | By default, uses a simple email regex that matches most email addresses. If `:rfc_5322`, uses a full RFC 5322 email regex that will match common typos as well. If `:rfc_5322_simple`, uses a simplified version of the previous regex to ignore some common typos. |
# | `:message`   | A custom message to use if the email is invalid.                                                                                                                                                                                                                    |
# | `:allow_nil` | If true, `nil` values are allowed.                                                                                                                                                                                                                                  |

class EmailValidator < LocalizedEachValidator
  # Regular expression describing valid emails.
  RFC5322_REGEX        = /(?:[a-z0-9!#$%&'*+\/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+\/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])/i
  RFC5322_SIMPLE_REGEX = /[a-z0-9!#$%&'*+\/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+\/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?/i
  BASIC_REGEX          = /[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}/i

  error_key :invalid_email

  # @private
  def valid?(_, _, value)
    regex = case options[:format]
              when :rfc_5322 then RFC5322_REGEX
              when :rfc_5322_simple then RFC5322_SIMPLE_REGEX
              else BASIC_REGEX
            end
    (value =~ /\A#{regex}\z/i || value =~ /\A.+\s+<#{regex}>\z/i) != nil
  end
end