#
#--
# 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
#

#
# this participant requires atom-tools from
#
# http://code.necronomicorp.com/trac/atom-tools
#
# atom-tools' license is X11/MIT
#

require 'monitor'

require 'atom/collection' # gem 'atom-tools'

require 'openwfe/participants/participant'


module OpenWFE::Extras

  #
  # Stores the incoming workitem into an 'atom feed'
  #
  # An example :
  #
  #   feed0 = AtomFeedParticipant.new(
  #     20,              # no more than 20 entries are kept
  #     """
  #     <p>
  #       <h1>${f:colour}</h1>
  #     </p>
  #     """)             # the template for each entry
  #
  # The 'template' parameter may contain an instance of File instead of
  # an instance of String.
  #
  #   feed0 = AtomFeedParticipant.new(
  #     20, File.new("path/to/my/atom/template.txt")
  #
  # The template can be passed as the second parameter (after the max entry
  # count) or as a block :
  #
  #   feed1 = AtomFeedParticipant.new(20) do |flow_expression, atom_participant, workitem|
  #     #
  #     # usually only the workitem parameter is used
  #     # but the other two allow for advanced tricks...
  #
  #     atom_participant.content_type = "xml"
  #       # by default, it's "xhtml"
  #
  #     s = "<task>"
  #     s << "<name>#{workitem.task_name}</name>"
  #     s << "<assignee>#{workitem.task_assignee}</assignee>"
  #     s << "<duedate>#{workitem.task_duedate}</duedate>"
  #     s << "</task>"
  #
  #     # the block is supposed to 'return' a string which is the
  #     # effective template
  #   end
  #
  # This participant uses
  # "atom-tools" from http://code.necronomicorp.com/trac/atom-tools
  #
  #
  class AtomFeedParticipant
    include MonitorMixin
    include OpenWFE::LocalParticipant
    include OpenWFE::TemplateMixin

    #
    # Made accessible so that blocks may set it.
    #
    attr_accessor :content_type

    def initialize (max_item_count, template=nil, &block)

      super() # very important as this class includes MonitorMixin

      @template = template
      @max_item_count = max_item_count
      @block_template = block

      @feed = Atom::Feed.new("http://localhost")
      @content_type = "xhtml"
    end

    def consume (workitem)

      e = Atom::Entry.new

      e.id = \
        "#{workitem.fei.workflow_instance_id}--" +
        "#{workitem.fei.expression_id}"

      e.title = workitem.atom_entry_title
      e.content = render(workitem)

      e.content["type"] = @content_type

      @feed << e

      @feed = @feed[0, @max_item_count] \
        if @feed.entries.size > @max_item_count

      publish workitem

      reply_to_engine workitem
    end

    protected

      #
      # This base implementation simply calls the eval_template()
      # method of the TemplateMixin.
      # Feel free to override this render() method for custom
      # representations.
      #
      def render (workitem)

        eval_template workitem
      end

      #
      # For the moment, just dumps the feed into a file.
      #
      def publish (workitem)
        synchronize do
          filename = "work/atom_#{workitem.participant_name}.xml"
          f = File.open(filename, "w")
          f << @feed.to_s
          f.close()
        end
      end
  end

end