class EventMachine::Reactor

def add_selectable io
  @selectables[io.uuid] = io
end

def close_loopbreaker
  @loopbreak_writer.close
  @loopbreak_writer = nil
end

def crank_selectables
  #$stderr.write 'R'
  readers = @selectables.values.select {|io| io.select_for_reading?}
  writers = @selectables.values.select {|io| io.select_for_writing?}
  s = select( readers, writers, nil, @timer_quantum)
  s and s[1] and s[1].each {|w| w.eventable_write }
  s and s[0] and s[0].each {|r| r.eventable_read }
  @selectables.delete_if {|k,io|
    if io.close_scheduled?
      io.close
      begin
        EventMachine::event_callback io.uuid, ConnectionUnbound, nil
      rescue ConnectionNotBound; end
      true
    end
  }
end

def get_selectable uuid
  @selectables[uuid]
end

def initialize
  initialize_for_run
end

def initialize_for_run
  @running = false
  @stop_scheduled = false
  @selectables ||= {}; @selectables.clear
  @timers = SortedSet.new # []
  set_timer_quantum(0.1)
  @current_loop_time = Time.now
  @next_heartbeat = @current_loop_time + HeartbeatInterval
end

def install_oneshot_timer interval
  uuid = UuidGenerator::generate
  #@timers << [Time.now + interval, uuid]
  #@timers.sort! {|a,b| a.first <=> b.first}
  @timers.add([Time.now + interval, uuid])
  uuid
end

def open_loopbreaker
  # Can't use an IO.pipe because they can't be set nonselectable in Windows.
  # Pick a random localhost UDP port.
  #@loopbreak_writer.close if @loopbreak_writer
  #rd,@loopbreak_writer = IO.pipe
  @loopbreak_reader = UDPSocket.new
  @loopbreak_writer = UDPSocket.new
  bound = false
  100.times {
    @loopbreak_port = rand(10000) + 40000
    begin
      @loopbreak_reader.bind "127.0.0.1", @loopbreak_port
      bound = true
      break
    rescue
    end
  }
  raise "Unable to bind Loopbreaker" unless bound
  LoopbreakReader.new(@loopbreak_reader)
end

def run
  raise Error.new( "already running" ) if @running
  @running = true
  begin
    open_loopbreaker
    loop {
      @current_loop_time = Time.now
      break if @stop_scheduled
      run_timers
      break if @stop_scheduled
      crank_selectables
      break if @stop_scheduled
      run_heartbeats
    }
  ensure
    close_loopbreaker
    @selectables.each {|k, io| io.close}
    @selectables.clear
    @running = false
  end
end

def run_heartbeats
  if @next_heartbeat <= @current_loop_time
    @next_heartbeat = @current_loop_time + HeartbeatInterval
    @selectables.each {|k,io| io.heartbeat}
  end
end

def run_timers
  @timers.each {|t|
    if t.first <= @current_loop_time
      @timers.delete t
      EventMachine::event_callback "", TimerFired, t.last
    else
      break
    end
  }
  #while @timers.length > 0 and @timers.first.first <= now
  #  t = @timers.shift
  #  EventMachine::event_callback "", TimerFired, t.last
  #end
end

def set_timer_quantum interval_in_seconds
  @timer_quantum = interval_in_seconds
end

def signal_loopbreak
  begin
    @loopbreak_writer.send('+',0,"127.0.0.1",@loopbreak_port) if @loopbreak_writer
  rescue IOError; end
end

def stop
  raise Error.new( "not running") unless @running
  @stop_scheduled = true
end