module ActiveResource
  # A module to support custom REST methods and sub-resources, allowing you to break out
  # of the "default" REST methods with your own custom resource requests.  For example,
  # say you use Rails to expose a REST service and configure your routes with:
  #
  #    map.resources :people, :new => { :register => :post },
  #                           :member => { :promote => :put, :deactivate => :delete }
  #                           :collection => { :active => :get }
  #
  #  This route set creates routes for the following HTTP requests:
  #
  #    POST    /people/new/register.xml # PeopleController.register
  #    PUT     /people/1/promote.xml    # PeopleController.promote with :id => 1
  #    DELETE  /people/1/deactivate.xml # PeopleController.deactivate with :id => 1
  #    GET     /people/active.xml       # PeopleController.active
  #
  # Using this module, Active Resource can use these custom REST methods just like the
  # standard methods.
  #
  #   class Person < ActiveResource::Base
  #     self.site = "http://37s.sunrise.i:3000"
  #   end
  #
  #   Person.new(:name => 'Ryan).post(:register)  # POST /people/new/register.xml
  #   # => { :id => 1, :name => 'Ryan' }
  #
  #   Person.find(1).put(:promote, :position => 'Manager') # PUT /people/1/promote.xml
  #   Person.find(1).delete(:deactivate) # DELETE /people/1/deactivate.xml
  #
  #   Person.get(:active)  # GET /people/active.xml
  #   # => [{:id => 1, :name => 'Ryan'}, {:id => 2, :name => 'Joe'}]
  #
  module CustomMethods 
    def self.included(base)
      base.class_eval do
        extend ActiveResource::CustomMethods::ClassMethods
        include ActiveResource::CustomMethods::InstanceMethods

        class << self
          alias :orig_delete :delete

          # Invokes a GET to a given custom REST method. For example:
          #
          #   Person.get(:active)  # GET /people/active.xml
          #   # => [{:id => 1, :name => 'Ryan'}, {:id => 2, :name => 'Joe'}]
          #
          #   Person.get(:active, :awesome => true)  # GET /people/active.xml?awesome=true
          #   # => [{:id => 1, :name => 'Ryan'}]
          #
          # Note: the objects returned from this method are not automatically converted
          # into ActiveResource::Base instances - they are ordinary Hashes. If you are expecting
          # ActiveResource::Base instances, use the <tt>find</tt> class method with the
          # <tt>:from</tt> option. For example:
          #
          #   Person.find(:all, :from => :active)
          def get(custom_method_name, options = {})
            connection.get(custom_method_collection_url(custom_method_name, options), headers)
          end

          def post(custom_method_name, options = {}, body = '')
            connection.post(custom_method_collection_url(custom_method_name, options), body, headers)
          end

          def put(custom_method_name, options = {}, body = '')
            connection.put(custom_method_collection_url(custom_method_name, options), body, headers)
          end

          def delete(custom_method_name, options = {})
            # Need to jump through some hoops to retain the original class 'delete' method
            if custom_method_name.is_a?(Symbol)
              connection.delete(custom_method_collection_url(custom_method_name, options), headers)
            else
              orig_delete(custom_method_name, options)
            end
          end
        end
      end
    end

    module ClassMethods
      def custom_method_collection_url(method_name, options = {})
        prefix_options, query_options = split_options(options)
        "#{prefix(prefix_options)}#{collection_name}/#{method_name}.#{format.extension}#{query_string(query_options)}"
      end
    end
    
    module InstanceMethods
      def get(method_name, options = {})
        connection.get(custom_method_element_url(method_name, options), self.class.headers)
      end
      
      def post(method_name, options = {}, body = '')
        if new?
          connection.post(custom_method_new_element_url(method_name, options), (body.nil? ? to_xml : body), self.class.headers)
        else
          connection.post(custom_method_element_url(method_name, options), body, self.class.headers)
        end
      end
      
      def put(method_name, options = {}, body = '')
        connection.put(custom_method_element_url(method_name, options), body, self.class.headers)
      end
      
      def delete(method_name, options = {})
        connection.delete(custom_method_element_url(method_name, options), self.class.headers)
      end


      private
        def custom_method_element_url(method_name, options = {})
          "#{self.class.prefix(prefix_options)}#{self.class.collection_name}/#{id}/#{method_name}.#{self.class.format.extension}#{self.class.send!(:query_string, options)}"
        end
      
        def custom_method_new_element_url(method_name, options = {})
          "#{self.class.prefix(prefix_options)}#{self.class.collection_name}/new/#{method_name}.#{self.class.format.extension}#{self.class.send!(:query_string, options)}"
        end
    end
  end
end