#!/usr/bin/python
"""UDP test client.

This implements the client side of the UDP connection testing tool to evaluate
the effective speed of a link using bursts of UDP traffic.
"""
import select
import socket
import struct
import sys
import time

import options

optspec = """
udp_test_client.py [options...] host_ip
--
i,interval=     Specify the cycle interval in seconds [2.0]
t,time=         Specify the test length in seconds; zero means unlimited. [0]
"""

try:
  import monotime
except ImportError:
  pass
try:
  monotime = time.monotime
except AttributeError:
  monotime = time.time


def parse_address(raw_address):
  port = 5001

  raw_host_addr = raw_address.split(':')
  if len(raw_host_addr) > 1:
    port = int(raw_host_addr[1])

  return (raw_host_addr[0], port)


def main():
  o = options.Options(optspec)
  opt, _, extra = o.parse(sys.argv[1:])

  interval_length = float(opt.interval)

  host_addr = parse_address(extra[0])
  sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

  packet_counter = 0
  packets_sent = 0
  packets_recv = 0
  respond_time = monotime()
  start_time = monotime()
  server_count = 0
  last_heard = monotime()

  print 'Host Address: %s' % host_addr[0]

  while True:
    wait_time = interval_length - (monotime() - respond_time)
    if wait_time < 0:
      wait_time = 0
    sock_ready, _, _ = select.select([sock], [], [], wait_time)
    if sock_ready:
      data = sock.recv(65536)
      magic, pack_type = struct.unpack('!4s4s', data[0:8])

      if magic != 'TPDO':
        continue

      if pack_type == 'RNNG':
        packet_counter += 1
        _, _, server_count = struct.unpack('!4s4si', data[0:12])
        last_heard = monotime()
    if monotime() - respond_time > interval_length:
      temp_time = monotime()
      counter_msg = struct.pack('!4s4siid', 'TPDO', 'UPDT', server_count,
                                packet_counter, temp_time)
      sock.sendto(counter_msg, host_addr)

      if packet_counter > 0:
        cycle_time = temp_time - respond_time
        send_rate = server_count - packets_sent
        recv_rate = packet_counter - packets_recv
        if send_rate == 0:
          success_rate = 0
        else:
          success_rate = float(recv_rate) / send_rate

        print ('Send Rate: %.2fMbps, Receive Rate: %.2fMbps, '
               'Success Rate: %.2f%%' %
               (send_rate * len(data) * 8 / 1000000 / cycle_time,
                recv_rate * len(data) * 8 / 1000000 / cycle_time,
                success_rate * 100))

        packets_sent = server_count
        packets_recv = packet_counter
      respond_time = monotime()
    if monotime() - start_time > float(opt.time) and opt.time:
      break

    if monotime() - last_heard > interval_length * 4:
      sys.stderr.write('Failed, Connection Timed out')
      sys.exit(1)

if __name__ == '__main__':
  main()