#
#--
# Copyright (c) 2007, John Mettraux, OpenWFE.org
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without 
# modification, are permitted provided that the following conditions are met:
# 
# . Redistributions of source code must retain the above copyright notice, this
#   list of conditions and the following disclaimer.  
# 
# . Redistributions in binary form must reproduce the above copyright notice, 
#   this list of conditions and the following disclaimer in the documentation 
#   and/or other materials provided with the distribution.
# 
# . Neither the name of the "OpenWFE" nor the names of its contributors may be
#   used to endorse or promote products derived from this software without
#   specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
# POSSIBILITY OF SUCH DAMAGE.
#++
#

#
# "made in Japan"
#
# John Mettraux at openwfe.org
#

require 'yaml'
require 'socket'
require 'timeout'

require 'openwfe/orest/xmlcodec'
require 'openwfe/participants/participant'


module OpenWFE

    #
    # This participant implementation dispatches workitems over TCP sockets.
    # By default the workitem are dumped as YAML strings, but you can override 
    # the encode_workitem(wi) method.
    #
    # A small example :
    #
    #     require 'openwfe/particpants/socketparticipants'
    #
    #     sp = OpenWFE::SocketParticipant.new("target.host.xx", 7007)
    #
    #     engine.register_participant("Alfred", sp)
    #
    class SocketParticipant

        attr_accessor :host, :port

        #
        # The constructor
        #
        def initialize (host, port)

            @host = host
            @port = port
        end

        #
        # The method called by the engine for each incoming workitem.
        # Will dispatch the workitem over a TCP connection.
        #
        def consume (workitem)

            dispatch(workitem)
        end

        def dispatch (workitem)

            socket = TCPSocket.new(@host, @port)
            socket.puts encode_workitem(workitem)
            socket.puts
            socket.close_write

            #print "\n__socket.closed? #{socket.closed?}"

            reply = fetch_reply(socket)

            socket.close

            decode_reply(reply)
        end

        #
        # A 'static' method for dispatching workitems, you can use it
        # directly, without instantiating the SocketParticipant :
        #
        #     require 'openwfe/participants/socketparticipants'
        #
        #     SocketParticipant.dispatch("127.0.0.1", 7007, workitem)
        #
        def SocketParticipant.dispatch (host, port, workitem)

            SocketParticipant.new(host, port).dispatch(workitem)
        end

        protected

            #
            # By default, uses YAML to serialize the workitem
            # (of course you can override this method).
            #
            def encode_workitem (wi)
                YAML.dump(wi)
            end

            #
            # By default, will just return the reply without touching it
            #
            def decode_reply (r)
                r
            end

            #
            # The code that waits for the reply from the server, nicely
            # wrapped inside a timeout and a rescue block.
            #
            def fetch_reply (socket)

                reply = ""

                begin

                    timeout(7) do
                        while true
                            r = socket.gets
                            break unless r
                            reply << r
                        end
                    end

                rescue Exception => e
                    puts e
                    raise "timeout while waiting for reply"
                end

                reply
            end
    end

    #
    # This extension of of SocketParticipant can be used to dispatch
    # workitems towards an OpenWFEja instance, but OpenWFEru's SocketListener
    # understands XML workitems as well.
    #
    class XmlSocketParticipant < SocketParticipant

        #def initialize (host, port)
        #    super
        #end

        #
        # A 'static' method for dispatching workitems, you can use it
        # directly, without instantiating the SocketParticipant :
        #
        #     require 'openwfe/participants/socketparticipants'
        #
        #     SocketParticipant.dispatch("127.0.0.1", 7007, workitem)
        #
        def XmlSocketParticipant.dispatch (host, port, workitem)

            XmlSocketParticipant.new(host, port).consume(workitem)
        end

        protected

            #
            # This implementation encodes the workitem as an XML document.
            # This is compatible with OpenWFEja.
            #
            def encode_workitem (wi)

                sxml = OpenWFE::XmlCodec::encode(wi)

                s = "xmlCoder #{sxml.length}\n"
                s << "\n"
                s << sxml
                s << "\n"
                s << "\n"
                s
            end
    end

end