# Copyright 2010 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License 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.

require 'json'
require 'addressable/template'

module Google #:nodoc:
  class APIClient #:nodoc:
    ##
    # A discovery document handler.
    class Discovery

      ##
      # The default discovery configuration values.  These may be overrided
      # simply by passing in the same key to the constructor.
      DEFAULTS = {
      }

      ##
      # A set of default configuration values specific to each service.  These
      # may be overrided simply by passing in the same key to the constructor.
      SERVICE_DEFAULTS = {
      }

      ##
      # Creates a new API discovery handler.
      #
      # @param [Hash] options
      #   <code>:service</code>::
      #     The name of the service.
      #   <code>:service_version</code>::
      #     The version of the service.
      #   <code>:discovery_uri</code>::
      #     The URI of the discovery document.
      #
      # @return [Google::APIClient::Discovery] The API discovery handler.
      def initialize(options={})
        if options[:service] && SERVICE_DEFAULTS[options[:service]]
          @options = DEFAULTS.merge(SERVICE_DEFAULTS[options[:service]])
        else
          @options = DEFAULTS.clone
        end
        @options.merge!(options)
        if @options[:service] && !@options[:discovery_uri]
          service_id = @options[:service]
          service_version = @options[:service_version] || '1.0'
          @options[:discovery_uri] =
            "http://www.googleapis.com/discovery/0.1/describe" +
            "?api=#{service_id}&apiVersion=#{service_version}"
        end
        unless @options[:discovery_uri]
          raise ArgumentError,
            'Missing required configuration value, :discovery_uri.'
        end
        # Handle any remaining configuration here
      end

      ##
      # Returns the configuration of the handler.  Configuration options that
      # are not recognized by the handler are ignored.
      #
      # @return [Hash] The configuration options.
      def options
        return @options
      end

      ##
      # Returns the URI of the discovery document.
      #
      # @return [String] The URI of the discovery document.
      def discovery_uri
        return @options[:discovery_uri]
      end
    end
  end
end