#
#--
# Copyright (c) 2007-2008, 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 'json' # gem 'json_pure'

require 'openwfe/util/xml'
require 'openwfe/expressions/flowexpression'


module OpenWFE

  #
  # This expression implementation gathers the 'f', 'q' and 'v' expressions,
  # along with their fullname 'field', 'variable' and 'quote'.
  #
  # These expressions place the value of the corresponding, field, variable
  # or quoted (direct value) in the 'result' field of the current workitem.
  #
  #   sequence do
  #
  #     set :field => "f0", :value => "fox"
  #     set :variable => "v0", :value => "vixen"
  #
  #     set :field => "f1" do
  #       v "v0"
  #     end
  #     set :variable => "v1" do
  #       f "f0"
  #     end
  #     set :variable => "v2" do
  #       f "f0"
  #     end
  #   end
  #
  # Well, this is perhaps not the best example.
  #
  class FqvExpression < FlowExpression

    names :f, :q, :v, :field, :quote, :variable

    #
    # apply / reply

    def apply (workitem)

      name = @fei.expression_name[0, 1]
      text = fetch_text_content workitem

      method = MAP[name]

      result = self.send method, text, workitem

      workitem.set_result(result) if result != nil

      reply_to_parent workitem
    end

    protected

      MAP = {
        "f" => :field,
        "q" => :quote,
        "v" => :variable
      }

      def field (text, workitem)
        workitem.attributes[text]
      end

      def quote (text, workitem)
        text
      end

      def variable (text, workitem)
        self.lookup_variable(text)
      end
  end

  #
  # The 'a' or 'attribute' expression. Directly describing some
  # variable or list content in XML or in YAML.
  #
  #   _set :field => "list" do
  #     _a """
  #       <array>
  #         <string>a</string>
  #         <string>b</string>
  #         <number>3</number>
  #         <string>d</string>
  #         <null/>
  #         <false/>
  #         <string>it's over</string>
  #       </array>
  #     """
  #   end
  #
  # or
  #
  #   _set :field => "list" do
  #     _attribute """
  #   ---
  #   - a
  #   - b
  #   - c
  #     """
  #    end
  #
  # Note that it's actually easier to write :
  #
  #   _set :field => "list" do
  #     reval "[ 'a', 'b', 'c' ]"
  #   end
  #
  # but it's less secure. The best way might be :
  #
  #   set :field => "list", :value => [ 'a', 'b', 'c' ]
  #
  # Yet another way, as this <a> expression accepts JSON :
  #
  #   set :field => 'list' do
  #     a '[1,2,false,"my name"]'
  #   end
  #
  #
  class AttributeExpression < FlowExpression

    names :a, :attribute

    XML_REGEX = /<.*>/


    def apply (workitem)

      child = @children.first

      text = if child.is_a?(String)

        #child
        fetch_text_content workitem

      elsif child.is_a?(FlowExpressionId)

        exp = get_expression_pool.fetch_expression child
        ExpressionTree.to_s exp.raw_representation

      else

        child.to_s
      end

      text = text.strip

      result = if text[0, 3] == '---'

        from_yaml text

      elsif text.match(XML_REGEX)

        from_xml text
      end

      result = from_json(text) if result == nil

      #p [ :result, result, text ]

      workitem.set_result(result) if result != nil

      reply_to_parent workitem
    end

    protected

      def from_yaml (text)

        begin

          YAML.load text

        rescue Exception => e
          linfo { "from_yaml() failed : #{e}" }
          nil
        end
      end

      def from_xml (text)

        begin

          OpenWFE::Xml.from_xml text

        rescue Exception => e
          linfo { "from_xml() failed : #{e}" }
          nil
        end
      end

      def from_json (text)

        begin

          return JSON.parse(text) if defined?(JSON)

          return ActiveSupport::JSON.decode(text) \
            if defined?(ActiveSupport::JSON)

        rescue Exception => e
          linfo { "from_json() failed : #{e}" }
          nil
        end
      end
  end

end