#
#--
# Copyright (c) 2006-2007, 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 
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
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#++
#
# $Id: definitions.rb 2725 2006-06-02 13:26:32Z jmettraux $
#

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

require 'openwfe/utils'
require 'openwfe/rudefinitions'
require 'openwfe/expressions/filter'
require 'openwfe/expressions/timeout'


#
# The participant expression, in its own file
#

module OpenWFE

    #
    # Participants sit at the edge between the engine and the external
    # world. The participant expression transmit the workitem applied
    # to it to the Participant instance it looks up in the participant map
    # tied to the engine.
    #
    #  direct reference to participant alpha :
    #
    #     <participant ref="alpha" />
    #
    #  the name of the participant is the value found in 
    #  the field 'target' :
    #
    #     <participant field-ref="target" />
    #     <participant ref="${f:target}" />
    #
    #  the name of the participant is the value found in 
    #  the variable 'target' :
    #
    #     <participant variable-ref="target" />
    #     <participant ref="${target}" />
    #
    #  direct reference to participant 'alpha'
    #  if a subprocess named 'alpha' has been defined, the 
    #  subprocess will be called instead :
    #
    #     <alpha />
    #
    # The Participant expressions includes the FilterMixin and thus
    # understands and applies the "filter" attribute.
    #
    # Since OpenWFEru 0.9.9, the attributes of the participant expression are
    # set inside a hash field named 'params' just available to the participant.
    # Thus in
    #
    #     <participant ref="toto" task="play golf" location="Minami Center" />
    #
    # participant 'toto' will receive a workitem with a field named 'params'
    # containing the hash 
    # { "ref"=>"toto", "task"=>"play golf", "location"=>"Minami Center" }.
    # 
    # When the workitem gets back from the participant, the field 'params' is 
    # deleted.
    #
    # The participant expressions include the TimeoutMixin, it means that
    # a timeout can be stated :
    #
    #     <participant ref="toto" timeout="2w1d" />
    #
    # If after 2 weeks and 1 day (15 days), participant "toto" hasn't replied,
    # the workitem will get cancelled and the flow will resume (behind the 
    # scene, participant "toto", will receive a CancelItem instance bearing
    # the same FlowExpressionId as the initial workitem and the participant
    # implementation is responsible for the cancel application).
    #
    class ParticipantExpression < FlowExpression
        include FilterMixin
        include TimeoutMixin

        names :participant

        attr_accessor \
            :participant_name,
            :applied_workitem

        def apply (workitem)

            remove_timedout_flag workitem

            @applied_workitem = workitem.dup

            @participant_name = lookup_ref workitem

            @participant_name = fetch_text_content workitem \
                unless @participant_name

            schedule_timeout()

            filter_in workitem

            store_itself()
            
            workitem.params = lookup_attributes workitem

            get_participant_map.dispatch @participant_name, workitem
            get_participant_map.onotify @participant_name, :apply, workitem
                #
                # these two pmap calls were combined, but with the :reply
                # notification in reply_to_parent() it feels more
                # elegant like that
        end

        def reply_to_parent (workitem)

            get_participant_map.onotify @participant_name, :reply, workitem
                #
                # for 'listen' expressions waiting for replies

            unschedule_timeout()

            workitem.attributes.delete "params"

            filter_out workitem

            super workitem
        end

        #
        # The cancel() method of a ParticipantExpression is particular : it
        # will emit a CancelItem instance towards the participant itself
        # to notify it of the cancellation.
        #
        def cancel

            unschedule_timeout()

            wi = super()

            return wi unless @applied_workitem

            #
            # have to cancel the workitem on the participant side

            cancelitem = OpenWFE::CancelItem.new(@applied_workitem)
            get_participant_map.dispatch(@participant_name, cancelitem)

            nil
        end

        #
        # Upon timeout, the ParticipantExpression will cancel itself and
        # the flow will resume.
        #
        def trigger (scheduler)

            ldebug { "trigger() timeout requested for #{@fei.to_debug_s}" }

            begin

                #@scheduler_job_id = nil
                    #
                    # so that cancel won't unschedule without need 

                cancel()

                set_timedout_flag(@applied_workitem)

                reply_to_parent(@applied_workitem)
            rescue
                lerror do
                    "trigger() problem while timing out\n"+
                    OpenWFE::exception_to_s($!)
                end
            end
        end
    end

end