# Copyright 2011-2012 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
#     http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.

module AWS
  module Core
    class Client

      # When a client class extends this module, its API configuration is
      # parsed.  For each operation in the API configuration, one client
      # method is added.
      #
      # Clients extending QueryJSON all have in common their method of
      # serializing request (input) parameters and parsing response
      # (output) JSON.
      #
      module QueryJSON
          
        def self.extended base
          base.send(:include, ErrorParser)
          base.send(:define_client_methods)
        end
  
        # @return [Hash<Symbol,OptionGrammar>] Returns a hash option
        #   parsers.  Hash keys are client method names and hash
        #   values are {OptionGrammar} objects.
        # @private
        def option_parsers
          @option_parsers ||= {}
        end
  
        protected
  
        # Enumerates through the operations specified in the API 
        # configuration (yaml configuration file found in lib/api_config/)
        # and defines one request method per operation.
        def define_client_methods
          api_config[:operations].each do |op|
  
            method_name = op[:method]
  
            option_parsers[method_name] = OptionGrammar.customize(op[:inputs])
  
          end
        end
  
        def define_client_method method_name, operation
          add_client_request_method(method_name) do
  
            configure_request do |request, options|

              parser = self.class.option_parsers[method_name]
              x_amz_target = self.class::TARGET_PREFIX + operation

              request.headers["content-type"] = "application/x-amz-json-1.0"
              request.headers["x-amz-target"] = x_amz_target
              request.body = parser.to_json(options)

            end
  
            process_response do |response|
              response_body = response.http_response.body
              response_body = "{}" if response_body == ""
              data = JSON.load(response_body)
              MetaUtils.extend_method(response, :data) { data }
            end
  
            simulate_response do |response|
              data = {}
              MetaUtils.extend_method(response, :data) { data }
            end
  
          end
        end
  
        module ErrorParser
  
          def extract_error_details response
            if 
              response.http_response.status >= 300 and
              body = response.http_response.body and
              json = (JSON.load(body) rescue nil) and
              type = json["__type"] and
              matches = type.match(/\#(.*)$/)
            then
              code = matches[1]
              if code == 'RequestEntityTooLarge'
                message = 'Request body must be less than 1 MB'
              else
                message = json['message']
              end
              [code, message]
            end
          end
  
        end

      end
    end
  end
end