#!/usr/bin/env ruby


###########################################################################
# Copyright (c) 2017 Alan Yorinks - All Rights Reserved.
#
# This file is part of Ruby-Banyan.
#
# Ruby Banyan is free software; you can redistribute it and/or
# modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
# Version 3 as published by the Free Software Foundation; either
# or (at your option) any later version.
# This library 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 AFFERO GENERAL PUBLIC LICENSE
# along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#
# banyan_base.rb
#############################################################################

require 'rubygems'
require 'ffi-rzmq'
require 'socket'
require 'msgpack'
require 'optparse'

###################################################################
# This the banyan backplane for ruby. It must be started before
# any other banyan components are invoked.

###################################################################

# noinspection RubyResolve,RubyResolve

class BackPlane

  def initialize(subscriber_port: '43125', publisher_port: '43124',
                 process_name: 'Backplane', loop_time: 0.001)

    # This is the initializer for the Banyan BackPlane class. The class must be instantiated
    # before starting any other Python Banyan modules

    # :param subscriber_port: subscriber IP port number
    # :param publisher_port: publisher IP port number
    # :param backplane_name: name to appear on the console for this backplane
    # :param loop_time: event loop idle timer

    @subscriber_port = subscriber_port
    @publisher_port = publisher_port
    @process_name = process_name
    @loop_time = loop_time

    @back_plane_ip_address = Socket.ip_address_list[1].ip_address

    puts('************************************************************')
    # noinspection RubyResolve
    puts(process_name + ' BackPlane on IP address: ' +
             @back_plane_ip_address)
    puts('Subscriber Port = ' + @subscriber_port)
    puts('Publisher  Port = ' + @publisher_port)
    puts('Loop Time = ' + @loop_time.to_s + ' seconds')
    puts('************************************************************')

    # establish the zeromq sub and pub sockets and connect to the backplane
    @context = ZMQ::Context.create

    @subscriber = @context.socket ZMQ::SUB
    @publisher = @context.socket ZMQ::PUB

    # subscribe to all messages
    @subscriber.setsockopt ZMQ::SUBSCRIBE, ''

    # noinspection RubyResolve
    # this looks backwards, but is correct. the backplane
    # accepts messages and re-sends them.
    @subscriber.bind 'tcp://' + @back_plane_ip_address + ':' + @publisher_port
    @publisher.bind 'tcp://' + @back_plane_ip_address + ':' + @subscriber_port
    trap("INT") {puts "Control C detected - bye bye."; @publisher.close; @subscriber.close; @context.terminate; exit}

    loop do
      list = []
      p = @subscriber.recv_strings(list, ZMQ::DONTWAIT)
      begin
        if p == -1
          sleep(@loop_time)
          if ZMQ::Util.errno == ZMQ::EAGAIN
            next
          else
            puts ZMQ::Util.errno
          end
        else
          @publisher.send_strings(list, flags = ZMQ::DONTWAIT)
        end
      rescue Interrupt
        clean_up
      end
    end
  end

  def clean_up
    # cleanup before exiting

    @publisher.close
    @subscriber.close
    @context.terminate
    exit
  end
end

options = {publisher_port: '43124',
           subscriber_port: '43125', process_name: 'Unknown',
           loop_time: '0.01'}

optparse = OptionParser.new do |opts|

  opts.on('-p', '--p PUBLISHER PORT', 'Publisher Port Number') do |publisher_port|
    options[:publisher_port] = publisher_port
  end

  opts.on('-s', '--s SUBSCRIBER PORT', 'Subscriber Port Number') do |subscriber_port|
    options[:subscriber_port] = subscriber_port
  end

  opts.on('-n', '--n Process Name', 'Name Of This Banyan Component') do |process_name|
    options[:process_name] = process_name
  end

  opts.on('-t', '--t Loop Delay Time', 'Time In Seconds') do |loop_time|
    options[:loop_time] = loop_time
  end
  opts.on('-h', '--help', 'Display this screen') do
    puts opts
    exit
  end
end

begin
  optparse.parse!
end

options[:loop_time] = options[:loop_time].to_f
BackPlane.new(subscriber_port: options[:subscriber_port],
              publisher_port: options[:publisher_port],
              process_name: options[:process_name],
              loop_time: options[:loop_time])