#--
# CyborgHood, a distributed system management software.
# Copyright (c) 2009-2010 Marc Dequènes (Duck) <Duck@DuckCorp.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#++

require 'cyborghood/cyborg/interface'
require 'cyborghood/cyborg/conversation'
require 'cyborghood/cyborg/botnet_dsl'
require 'set'

module CyborgHood
  # default interface if not overridden
  # a mere "BotClient" would then always have a default basic interface
  class EmptyInterface
    include CyborgServerInterface
    include CyborgServerRootInterfaceAddon
  end

  module BotNetClientUNIXSocket
    def identifier_prefix
      "unix_socket"
    end

    def setup
      super
      @pending_conversation_close = Set.new
    end

    def peer_socket(peer)
      File.join(Config::RUN_DIR, peer.downcase + ".sock")
    end

    def contact_peer(peer, &block)
      if @comm_list.has_key? peer
        block.call @comm_list[peer]
      else
        if @comm_list_attempt.has_key? peer
          @comm_list_attempt[peer] << block
        else
          @comm_list_attempt[peer] = [block]

          # demultiplex callbacks
          callback = proc do |conversation|
            block_list = @comm_list_attempt[peer]
            # purge list at once to avoid races
            @comm_list_attempt.delete(peer)

            block_list.each do |block|
              block.call conversation
            end
          end
          begin
            EventMachine.connect_unix_domain(peer_socket(peer), Conversation, self, callback)
          rescue
            # TODO: retry (wait_timer + recursive call + counter)
            block.call false
          end
        end
      end
    end
  end

  module BotNet
    attr_reader :interface

    def self.included(base)
      case Config.instance.botnet.connection_type
      when 'unix_socket'
        return base.class_eval("include BotNetClientUNIXSocket")
      else
        raise CyberError.new(:unrecoverable, "config", "Unknown botnet connection type")
      end
    end

    def setup
      super
      @comm_list = {}
      @comm_list_attempt = {}
    end

    # used to quit properly and later to reuse communication channels
    def register_communication(peer, conversation)
      @comm_list[peer] = conversation
    end

    def unregister_communication(peer)
      @comm_list.delete(peer)
      @pending_conversation_close.delete(peer)
    end

    def ask_to_stop
      @comm_list.values.each {|conv| conv.bye }
      super
    end

    def interface
      EmptyInterface.instance
    end

    protected

    def process_system_notification(msg)
      if msg[:topic] == 'CONVERSATION IDLE'
        peer = @comm_list[msg[:peer]]
        return if peer.nil?

        peer.bye
      else
        super
      end
    end

    def ready_to_stop?
      @comm_list.empty? and super
    end
  end
end