#
#--
# 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
#

module OpenWFE

    #
    # ExpressionPool methods available via the engine.
    #
    module ExpoolMethods

        #--
        # METHODS FROM THE EXPRESSION POOL
        #
        # These methods are 'proxy' to method found in the expression pool.
        # They are made available here for a simpler model.
        #++

        #
        # Returns the list of applied expressions belonging to a given
        # workflow instance.
        # May be used to determine where a process instance currently is.
        #
        # This method returns all the expressions (the stack) a process
        # went through to reach its current state.
        #
        # If the unapplied optional parameter is set to true, all the
        # expressions (even those not yet applied) that compose the process
        # instance will be returned.
        #
        def process_stack (workflow_instance_id, unapplied=false)

            get_expression_pool.process_stack workflow_instance_id, unapplied
        end
        alias :get_process_stack :process_stack
        alias :get_flow_stack :process_stack

        #
        # A shortcut for process_stack(wfid, true).representation
        #
        # Returns the representation (tree) for the actual version of the
        # given process instance (returns the tree as running, modifications
        # included).
        #
        def process_representation (workflow_instance_id)

          process_stack(workflow_instance_id, true).representation
        end

        #
        # Lists all workflow (process) instances currently in the expool (in
        # the engine).
        # This method will return a list of "process-definition" expressions
        # (i.e. OpenWFE::DefineExpression objects -- each representing the root
        # element of a flow).
        #
        # :wfid ::
        #     will list only one process,
        #     <tt>:wfid => '20071208-gipijiwozo'</tt>
        # :parent_wfid ::
        #     will list only one process, and its subprocesses,
        #     <tt>:parent_wfid => '20071208-gipijiwozo'</tt>
        # :consider_subprocesses ::
        #     if true, "process-definition" expressions
        #     of subprocesses will be returned as well.
        # :wfid_prefix ::
        #     allows your to query for specific workflow instance
        #     id prefixes. for example :
        #     <tt>:wfid_prefix => "200712"</tt>
        #     for the processes started in December.
        # :wfname ::
        #     will return only the process instances who belongs to the given
        #     workflow [name].
        # :wfrevision ::
        #     usued in conjuction with :wfname, returns only the process
        #     instances of a given workflow revision.
        #
        def list_processes (options={})

            get_expression_pool.list_processes options
        end
        alias :list_workflows :list_processes

        #
        # Given any expression of a process, cancels the complete process
        # instance.
        #
        def cancel_process (exp_or_wfid)

            get_expression_pool.cancel_process exp_or_wfid
        end
        alias :cancel_flow :cancel_process
        alias :abort_process :cancel_process

        #
        # Cancels the given expression (and its children if any)
        # (warning : advanced method)
        #
        # Cancelling the root expression of a process is equivalent to
        # cancelling the process.
        #
        def cancel_expression (exp_or_fei)

            get_expression_pool.cancel_expression exp_or_fei
        end

        #
        # Forgets the given expression (make it an orphan)
        # (warning : advanced method)
        #
        def forget_expression (exp_or_fei)

            get_expression_pool.forget exp_or_fei
        end

        protected

            #
            # In case of wfid, returns the root expression of the process,
            # in case of fei, returns the expression itself.
            #
            def fetch_exp (fei_or_wfid)

                exp = if fei_or_wfid.is_a?(String)

                    get_expression_pool.fetch_root fei_or_wfid

                else

                    get_expression_pool.fetch_expression fei_or_wfid
                end

                exp or raise "no expression found for '#{fei_or_wfid.to_s}'"
            end
    end
end