#
#--
# 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 
# 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.
#++
#
# $Id: definitions.rb 2725 2006-06-02 13:26:32Z jmettraux $
#

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

require 'openwfe/workitem'
require 'openwfe/flowexpressionid'
require 'openwfe/expressions/flowexpression'
require 'openwfe/expressions/fe_utils'


#
# expressions like 'set' and 'unset' and their utility methods
#

module OpenWFE

    class SetValueExpression < FlowExpression

        def apply (workitem)

            if @children.length < 1
                workitem.attributes[FIELD_RESULT] = \
                    OpenWFE::lookup_value(self, workitem)
                reply(workitem)
                return
            end

            child = @children[0]

            if child.kind_of? OpenWFE::FlowExpressionId
                handle_child(child, workitem)
                return
            end

            #workitem.attributes[FIELD_RESULT] = child.to_s
            workitem.attributes[FIELD_RESULT] = \
                OpenWFE::fetch_text_content(self, workitem)

            reply(workitem)
        end

        def reply (workitem)

            vkey = lookup_attribute("variable", workitem)
            fkey = lookup_attribute("field", workitem)

            value = workitem.attributes[FIELD_RESULT]

            #puts "value is '#{value}'"

            if vkey
                set_variable(vkey, value)
            elsif fkey
                workitem.attributes[fkey] = value
            else
                raise "'variable' or 'field' attribute missing from 'set' expression"
            end

            reply_to_parent(workitem)
        end

        protected 

            def handle_child (child, workitem)

                child, _fei = get_expression_pool().fetch(child)

                if child.is_definition?
                    fei = get_expression_pool().evaluate(child, workitem)
                    workitem.attributes[FIELD_RESULT] = fei
                    reply(workitem)
                else
                    get_expression_pool().apply(child, workitem)
                end
            end

            #def determine_value (workitem)
            #    if @children.length > 0
            #        child = @children[0]
            #        if child.kind_of? FlowExpressionId
            #            return "nada"
            #        else
            #            return child
            #        end
            #    end
            #    return OpenWFE::lookup_value(self, workitem)
            #end
    end

    class UnsetValueExpression < FlowExpression

        def apply (workitem)

            vkey = lookup_attribute("variable", workitem)
            fkey = lookup_attribute("field", workitem)

            if vkey
                delete_variable(vkey)
            elsif fkey
                workitem.attributes.delete(fkey)
            else
                raise "attribute 'variable' or 'field' is missing for 'unset' expression"
            end

            reply_to_parent(workitem)
        end

        #def reply (workitem)
        #end
    end

    class ComparisonExpression < FlowExpression

        def apply (workitem)

            value_a = OpenWFE::lookup_value(self, workitem)
            value_b = OpenWFE::lookup_value(self, workitem, 'other')

            result = compare(value_a, value_b)

            ldebug { "apply() result is '#{result}'  #{@fei.to_debug_s}" }

            OpenWFE::set_result(workitem, result)

            reply_to_parent(workitem)
        end

        protected

            def compare (a, b)
                raise "not yet implemented : '#{@fei.expressionName}'"
            end
    end

    #
    # <equals/>
    #
    class EqualsExpression < ComparisonExpression

        protected

            def compare (a, b)
                #ldebug { "compare()  #{fei.to_debug_s}" }
                #ldebug { "compare() '#{a}' == '#{b}'" }
                return a == b
            end
    end

    #
    #     <if/>
    #
    class IfExpression < FlowExpression

        attr_accessor \
            :condition_replied

        def apply (workitem)

            reply_to_parent(workitem) if @children.length < 1

            @condition_replied = false

            store_itself()

            get_expression_pool.apply(@children[0], workitem)
        end

        def reply (workitem)

            if @condition_replied
                reply_to_parent(workitem)
                return
            end

            result = workitem.attributes[FIELD_RESULT]

            @condition_replied = true

            store_itself()

            if result
                apply_consequence(1, workitem)
            else
                apply_consequence(2, workitem)
            end
        end

        def reply_to_parent(workitem)
            clean_children()
            super(workitem)
        end

        protected

            def apply_consequence (index, workitem)
                if index >= @children.length
                    reply_to_parent(workitem)
                else
                    get_expression_pool.apply(@children[index], workitem)
                end
            end
    end

end