#
#--
# 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/utils'
require 'openwfe/util/scheduler'
require 'openwfe/expressions/flowexpression'


module OpenWFE

    #
    # An environment is a store for variables.
    # It's an expression as it's storable in the expression pool.
    #
    class Environment < FlowExpression
        include Schedulable

        names :environment

        attr_accessor \
            :variables

        def initialize \
            (id, parent, environment_id, application_context, attributes)

            super(id, parent, environment_id, application_context, attributes)

            @variables = {}
        end

        def [] (key)

            #if OpenWFE::starts_with(key, "//")
            #    return get_expression_pool()\
            #        .get_engine_environment()[key[2..-1]]
            #end
            #if OpenWFE::starts_with(key, "/")
            #    return get_root_environment()[key[1..-1]]
            #end

            value = @variables[key]

            return value \
                if @variables.has_key?(key) or is_engine_environment?
                #if value or is_engine_environment?

            return get_parent[key] if @parent_id

            return get_expression_pool.fetch_engine_environment[key]
        end

        def []= (key, value)

            #if OpenWFE::starts_with(key, "//")
            #    key = key[2..-1]
            #    get_expression_pool().fetch_engine_environment()[key] = value
            #elsif OpenWFE::starts_with(key, "/")
            #    key = key[1..-1]
            #    get_root_environment()[key] = value
            #else
            #    @variables[key] = value
            #    store_itself()
            #    #ldebug { "[]= #{@fei.to_debug_s}  :  '#{key}' -> '#{value}'" }
            #end

            @variables[key] = value
            store_itself()
        end

        def delete (key)

            #if OpenWFE::starts_with(key, "//")
            #    key = key[2..-1]
            #    get_expression_pool().fetch_engine_environment().delete(key)
            #elsif OpenWFE::starts_with(key, "/")
            #    key = key[1..-1]
            #    get_root_environment().delete(key)
            #else
            #    @variables.delete(key)
            #    store_itself()
            #end

            @variables.delete key
            store_itself()
        end

        #
        # This method is usually called before the environment gets wiped
        # out of the expression pool.
        # It takes care of removing subprocess templates pointed at by
        # variables in this environment.
        #
        def unbind ()

            @variables.each do |key, value|

                #ldebug { "unbind() '#{key}' => #{value.class}" }

                if value.kind_of? FlowExpressionId
                    get_expression_pool().remove(value)
                elsif value.kind_of? FlowExpression
                    value.cancel
                end
            end
        end

        #
        # Returns true if this environment is the engine environment
        #
        def is_engine_environment?
            return @fei == get_expression_pool().engine_environment_id
        end

        #
        # Should never get used, only the reschedule() method is relevant
        # for the Schedulable aspect of an environment expression.
        #
        def trigger (params)
            raise "an environment should never get directly triggered"
        end

        #
        # Will reschedule any 'Schedulable' variable found in this environment
        # this method especially targets cron expressions that are stored
        # as variables and need to be rescheduled upon engine restart.
        #
        def reschedule (scheduler)

            @variables.each do |key, value|
                ldebug { "reschedule()  - item of class #{value.class}" }
                next unless value.kind_of? Schedulable
                value.application_context = @application_context
                value.reschedule(scheduler)
            end

            store_itself()
        end

        #
        # Returns the top environment for the process instance.
        #
        def get_root_environment ()

            #ldebug { "get_root_environment()\n#{self}" }

            return self if not @parent_id
            return get_parent().get_root_environment()
        end
    end

end