#
#--
# 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

  #
  # A small mixin providing value for looking up the attributes
  # variable/var/v and field/fld/f.
  #
  module ValueMixin

    #
    # Expressions that include the ValueMixin let it gather values and
    # then, in their reply() methods do the job with the values.
    # The gathering task is performed by the ValueMixin.
    #
    def apply (workitem)

      escape = lookup_boolean_attribute('escape', workitem, false)

      if @children.length < 1

        workitem.attributes[FIELD_RESULT] =
          lookup_value workitem, :escape => escape

        reply workitem
        return
      end

      child = @children.first

      if child.kind_of?(OpenWFE::FlowExpressionId)

        handle_child child, workitem
        return
      end

      workitem.attributes[FIELD_RESULT] =
        fetch_text_content workitem, escape

      reply workitem
    end

    def lookup_variable_attribute (workitem)

      lookup [ "variable", "var", "v" ], workitem
    end

    def lookup_field_attribute (workitem)

      lookup [ "field", "fld", "f" ], workitem
    end

    protected

      def handle_child (child, workitem)

        raw_child, _fei = get_expression_pool.fetch(child)

        if raw_child.is_definition?

          #body_fei = get_expression_pool.evaluate child, workitem
          #workitem.attributes[FIELD_RESULT] = body_fei

          workitem.attributes[FIELD_RESULT] = raw_child
            #
            # storing the child raw expression

          reply workitem
        else

          get_expression_pool.apply raw_child, workitem
        end
      end

    private

      def lookup (name_array, workitem)

        name_array.each do |n|
          v = lookup_string_attribute n, workitem
          return v if v
        end

        nil
      end
  end

end