module GrapeDSL
  module Extend
    module Headers

      # example in yaml format
      # "header_name":
      #  - "header values"
      #  - "header value 2"
      #
      #
      # real  example for cors
      # "Access-Control-Allow-Headers":
      #    - "X-Idp-Id"
      #    - "X-Token"
      #    - "Content-Type"
      # "Access-Control-Allow-Origin":
      #    - "*"
      # "Access-Control-Allow-Methods":
      #    - HEAD
      #    - OPTIONS
      #    - GET
      #    - POST
      #    - PUT
      #    - DELETE
      #
      #
      # This will give headers to all call request response made after this
      # make sure to load BEFORE every route call going to be made
      def response_headers_to_new_calls(config_obj=nil)

        Grape::Endpoint.config_obj= config_obj unless config_obj.nil?
        Grape::API.inject_singleton_method :inherited, add: "after" do |subclass|

          subclass.class_eval do

            before do
              Grape::Endpoint.header_config_obj.each do |header_key,header_value|
                header header_key, header_value.join(', ')
              end
            end

          end

        end

        return nil
      end

      # same config obj format like to "response_headers_to_new_calls"
      # this will create headers for the options call to ALL already made route
      # make sure to load after every route has been made
      def response_headers_to_routes_options_request(config_obj=nil)

        Grape::Endpoint.header_config_obj= config_obj unless config_obj.nil?
        Grape::API.subclasses.each do |rest_api_model|
          rest_api_model.routes.map { |route| route.route_path.split('(.:format)')[0] }.uniq.each do |path|
            rest_api_model.class_eval do

              options path do
                Grape::Endpoint.header_config_obj.each do |header_key,header_value|
                  header header_key, header_value.join(', ')
                end
              end

            end
          end

        end

        return nil
      end

    end
  end
end

Grape.__send__ :extend, ::GrapeDSL::Extend::Headers