require 'thread'
require 'monitor'
require 'singleton'

module MirrorConcurrentUtil
	THREAD_COUNT = 10
	QUEUE_SIZE = 20

	class MirrorThreadPool
	  include Singleton
	  include MonitorMixin

	  attr_accessor :thread_pool, :work_queue, :thread_available

      def initialize
	    @thread_pool = Array.new(MirrorConcurrentUtil::THREAD_COUNT)
	    @work_queue = SizedQueue.new(MirrorConcurrentUtil::QUEUE_SIZE)
	    @threads_available = self.new_cond
	  end

	end

	class MirrorProducer
	  def self.run(jobs) do
	  	thread_pool = MirrorThreadPool.instance.thread_pool
	  	threads_available = MirrorThreadPool.instance.threads_available
	  	work_queue = MirrorThreadPool.instance.work_queue

	    Thread.new do
	      jobs.each do |job|
	        work_queue << job

	        thread_pool.synchronize do
	          threads_available.signal
	        end
	      end
	    end
	  end
	end

	class MirrorConsumer
	  def self.run()
	    thread_pool = MirrorThreadPool.instance.thread_pool
	    threads_available = MirrorThreadPool.instance.threads_available
	    work_queue = MirrorThreadPool.instance.work_queue

	    Thread.new do
	      loop do
	        break if sysexit && MirrorThreadPool.instance.work_queue == 0
	        available_thread_index = nil

	        thread_pool.synchronize do
	          threads_available.wait_while do
	            thread_pool.select { |thread| thread.nil? || thread.status == false ||
	                                                         thread["finished"].nil? == false }.length == 0
	          end

	          available_thread_index = thread_pool.rindex { |thread| thread.nil? || thread.status == false ||
                                                                     thread["finished"].nil? == false }
            end

            job = work_queue.pop

            thread_pool[available_thread_index] = Thread.new(job) do
            	#Register rsync start time/date
            	#Run rsync(job)
            	#register rsync end time/date
            	Thread.current["finished"] = true

            	thread_pool.synchronize do
            	  threads_available.signal
            	end
            end
        end
      end
	end
end