#--
# gravaty
# Copyright © 2013, 2014, 2015, 2016, 2017, 2018, 2019  Marco Bresciani
#
# This file is part of gravaty.
#
# gravaty is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation, either version 3 of the License, or (at your
# option) any later version.
#
# gravaty is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License
# along with gravaty. If not, see <http://www.gnu.org/licenses/>.
#++

require 'cgi'

require_relative '../constants'

module Gravaty
  module Parsers

    # This class is an implementation of the Parsable duck type that
    # checks the default option. The only needed parameter is a valid
    # default option.
    #
    # Author:: {Marco Bresciani}[mailto:marcobresciani_1974@libero.it]
    # Copyright:: Copyright © 2013, 2014, 2015, 2016, 2017, 2018,
    # 2019  Marco Bresciani
    # License:: GNU General Public License version 3
    class Default

      # The parsable duck type interface to every parser usage.
      def parse(value = nil)
        unless value.nil? or value.empty?
          unless DEFAULT_OPTIONS.include? value
            valid = %w(http https).index {|scheme| valid?(value, scheme)}

            raise ArgumentError, I18n.t('error.uri', value: value) if valid.nil?
          end

          return 'd=' + CGI::escape(value).to_s
        end
        ''
      end

      # ------------------------ here starts the list of private methods

      private

      def valid?(value, scheme)
        return false if value.nil?
        return false if value.empty?

        parser = URI::Parser.new
        an_uri = parser.extract(value.downcase, scheme)

        return false if an_uri.nil?
        return false if an_uri.empty?

        begin
          an_uri = parser.parse an_uri[0]

          #See URI validation rules at
          # http://en.gravatar.com/site/implement/images/#default-image

          #rule 2
          return false if (an_uri.scheme == 'http') and
              (an_uri.port != Net::HTTP.http_default_port)
          return false if (an_uri.scheme == 'https') and
              (an_uri.port != Net::HTTP.https_default_port)

          #rule 3
          allowed = IMAGES_FORMATS
                        .index {|format| an_uri.path.end_with? format}
          return false if allowed.nil?

          #rule 4
          return false unless an_uri.query.nil?
        rescue
          return false
        end
        true
      end
    end
  end
end