#
#--
# Copyright (c) 2006-2008, 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 'openwfe/utils'


module OpenWFE

  #
  # This expression is used to launch/call a subprocess.
  #
  # For example :
  #
  #   <process-definition name="subtest0" revision="0">
  #     <sequence>
  #       <subprocess ref="sub0" a="A" b="B" c="C" />
  #       <sub0 a="A" b="B" c="C" />
  #     </sequence>
  #
  #     <process-definition name="sub0">
  #       <print>${a}${b}${c}</print>
  #     </process-definition>
  #
  #   </process-definition>
  #
  # It's totally OK to have URLs as referenced processes :
  #
  #   require 'openwfe/def'
  #
  #   class AnotherDefinition0 < OpenWFE::ProcessDefinition
  #    sequence do
  #      participant :ref => "toto"
  #      subprocess :ref => "http://company.process.server/def0.rb"
  #    end
  #   end
  #
  # (but the engine parameter :remove_definitions_allowed must be set to true,
  # as it's dangerous to fetch process definitions from other [untrusted]
  # hosts)
  #
  # The 'subprocess' expression accepts a 'forget' attribute :
  #
  #   class AnotherDefinition1 < OpenWFE::ProcessDefinition
  #     sequence do
  #       subprocess :ref => "my_subprocess", :forget => true
  #       participant :ref => "ringo"
  #     end
  #     process-definition :name => "my_subprocess" do
  #       participant :ref => "fake steve jobs"
  #     end
  #   end
  #
  # Note that a 'forgotten subprocess' will not have access to the variables
  # of its parent process.
  #
  # The 'subprocess' expression accepts an 'if' (or 'unless') attribute :
  #
  #   subprocess :ref => "interview_process", :if => "${f:screened}"
  #     # will trigger the subprocess only if the field screened
  #     # contains the string 'true' or the boolean 'true'
  #
  #   interview_process :if => "${f:screened}"
  #     # idem
  #
  #   interview_process :unless => "${f:has_had_problem_with_justice_?}"
  #     # well...
  #
  class SubProcessRefExpression < FlowExpression
    include ConditionMixin

    names :subprocess

    attr_accessor :subprocess_fei


    def apply (workitem)

      conditional = eval_condition(:if, workitem, :unless)

      return reply_to_parent(workitem) \
        if conditional == false

      ref = lookup_ref workitem

      raise "'subprocess' expression misses a 'ref', 'field-ref' or 'variable-ref' attribute" unless ref

      template_uri = OpenWFE::parse_known_uri ref

      template = template_uri || lookup_variable(ref)

      raise "did not find any subprocess named '#{ref}'" \
        if not template

      forget = lookup_boolean_attribute :forget, workitem

      params = lookup_attributes workitem

      text = fetch_text_content workitem, false
      params["0"] = text if text

      #puts
      #puts " ... params are #{params.keys.join(', ')}"
      #puts " ... values are #{params.values.join(', ')}"

      #requester = if forget
      #  @fei.workflow_instance_id
      #else
      #  @fei
      #end
      #sub_fei = get_expression_pool.launch_template(
      #  requester, nil, get_next_sub_id, template, workitem, params)

      sub_fei = get_expression_pool.launch_subprocess(
        self, template, forget, workitem, params)

      if forget
        reply_to_parent workitem.dup
      else
        @subprocess_fei = sub_fei.dup
        store_itself # to keep track of @subprocess_fei
      end
    end

    #
    # Takes care of cancelling the subprocess as well if any
    #
    def cancel

      return nil unless @subprocess_fei
      get_expression_pool.cancel @subprocess_fei
    end
  end

end