#
#--
# Copyright (c) 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.
#++
#
# $Id$
#

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

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

require 'monitor'

require 'rubygems'
require 'atom/collection'

require 'openwfe/participants/participant'


module OpenWFE

    #
    # Stores the incoming workitem into an 'atom feed'
    #
    # An example :
    #
    #     feed0 = AtomParticipant.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 = AtomParticipant.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 = AtomParticipant.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 AtomParticipant
        include LocalParticipant, MonitorMixin

        attr_accessor \
            :content_type       # blocks may manipulate them

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

            super()

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

            @feed = Atom::Collection.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.length > @max_item_count

            publish(workitem)

            reply_to_engine(workitem)
        end

        protected

            def render (workitem)

                fe = get_flow_expression(workitem)

                template = if @block_template
                    @block_template.call(fe, self, workitem)
                elsif @template
                    if @template.kind_of? File
                        @template.readlines
                    else
                        @template.to_s
                    end
                else
                    "(no template given)"
                end

                return OpenWFE::dosub(template, fe, workitem)
            end

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

end