module IMW
  module Schemes

    # Defines methods for accessing a resource over HTTP.  Uses
    # RestClient to implement the basic HTTP verbs (GET, POST, PUT,
    # DELETE, HEAD).
    module HTTP

      # Many websites have HTML content without an <tt>.html</tt>
      # extension so automatically extend +obj+ with
      # IMW::Resources::Formats::HTML in this case.
      def self.extended obj
        obj.extend(IMW::Formats::Html) if obj.extension.blank?
      end

      # Is this resource being accessed via HTTP?
      #
      # @return [true, false]
      def via_http?
        true
      end

      # Copy this resource to the +new_uri+.
      #
      # @param [String, IMW::Resource] new_uri
      # @return [IMW::Resource] the new resource
      def cp new_uri
        IMW::Tools::Transferer.new(:cp, self, new_uri).transfer!
      end
      

      # Return the basename of the URI or <tt>_index</tt> if it's
      # blank, as in the case of <tt>http://www.google.com</tt>.
      #
      # @return [String]
      def effective_basename
        (basename.blank? || basename =~ %r{^/*$}) ? "_index" : basename
      end

      # Send a GET request to this resource's URI.
      #
      # If the response doesn't have HTTP code 2xx, a RestClient
      # error will be raised.
      #
      # If a block is given then the response will be passed to the
      # block, even in case of a non-2xx code.
      #
      # See the documentation for
      # RestClient[http://rdoc.info/projects/archiloque/rest-client]
      # for more information.
      #
      # @param [Hash] headers the headers to include in the request
      # @yield [RestClient::Response] the response from the server
      # @return [RestClient::Response] the response from the server
      # @raise [RestClient::NotModified, RestClient::Unauthorized, RestClient::ResourceNotFound, RestClient::RequestFailed] error from RestClient on non-2xx response codes
      def get headers={}, &block
        make_restclient_request do
          RestClient.get(uri.to_s, headers, &block)
        end
      end

      # Send a POST request to this resource's URI with data
      # +payload+.
      #
      # If the response doesn't have HTTP code 2xx, a RestClient
      # error will be raised.
      #
      # If a block is given then the response will be passed to the
      # block, even in case of a non-2xx code.
      #
      # See the documentation for
      # RestClient[http://rdoc.info/projects/archiloque/rest-client]
      # for more information.
      #
      # @param [Hash, String] payload the data to send
      # @param [Hash] headers the headers to include in the request
      # @yield [RestClient::Response] the response from the server
      # @return [RestClient::Response] the response from the server
      # @raise [RestClient::NotModified, RestClient::Unauthorized, RestClient::ResourceNotFound, RestClient::RequestFailed] error from RestClient on non-2xx response codes
      def post payload, headers={}, &block
        make_restclient_request do
          RestClient.post(uri.to_s, payload, headers, &block)
        end
      end

      # Send a PUT request to this resource's URI with data
      # +payload+.
      #
      # If the response doesn't have HTTP code 2xx, a RestClient
      # error will be raised.
      #
      # If a block is given then the response will be passed to the
      # block, even in case of a non-2xx code.
      #
      # See the documentation for
      # RestClient[http://rdoc.info/projects/archiloque/rest-client]
      # for more information.
      #
      # @param [Hash, String] payload the data to send
      # @param [Hash] headers the headers to include in the request
      # @yield [RestClient::Response] the response from the server
      # @return [RestClient::Response] the response from the server
      # @raise [RestClient::NotModified, RestClient::Unauthorized, RestClient::ResourceNotFound, RestClient::RequestFailed] error from RestClient on non-2xx response codes
      def put payload, headers={}, &block
        make_restclient_request do
          RestClient.put(uri.to_s, payload, headers, &block)
        end
      end
      
      # Send a DELETE request to this resource's URI.
      #
      # If the response doesn't have HTTP code 2xx, a RestClient
      # error will be raised.
      #
      # If a block is given then the response will be passed to the
      # block, even in case of a non-2xx code.
      #
      # See the documentation for
      # RestClient[http://rdoc.info/projects/archiloque/rest-client]
      # for more information.
      #
      # @param [Hash] headers the headers to include in the request
      # @yield [RestClient::Response] the response from the server
      # @return [RestClient::Response] the response from the server
      # @raise [RestClient::NotModified, RestClient::Unauthorized, RestClient::ResourceNotFound, RestClient::RequestFailed] error from RestClient on non-2xx response codes
      def delete headers={}, &block
        make_restclient_request do
          RestClient.delete(uri.to_s, headers, &block)
        end
      end
      
      # Send a HEAD request to this resource's URI.
      #
      # If the response doesn't have HTTP code 2xx, a RestClient
      # error will be raised.
      #
      # If a block is given then the response will be passed to the
      # block, even in case of a non-2xx code.
      #
      # See the documentation for
      # RestClient[http://rdoc.info/projects/archiloque/rest-client]
      # for more information.
      #
      # @param [Hash] headers the headers to include in the request
      # @yield [RestClient::Response] the response from the server
      # @return [RestClient::Response] the response from the server
      # @raise [RestClient::NotModified, RestClient::Unauthorized, RestClient::ResourceNotFound, RestClient::RequestFailed] error from RestClient on non-2xx response codes
      def head headers={}, &block
        make_restclient_request do
          RestClient.head(uri.to_s, headers, &block)
        end
      end

      protected
      def make_restclient_request &block # :nodoc
        require 'restclient'
        begin
          yield
        rescue RestClient::NotModified, RestClient::Unauthorized, RestClient::ResourceNotFound, RestClient::RequestFailed => e
          raise IMW::NetworkError.new("#{e.class} -- #{e.message}")
        end
      end
    end
  end
end