# https://github.com/jholtmann/ip_discovery
"""Find other gateways and serve the udp socket"""

import os
import FindMyIP
from socket import *
from helpers import get_unix_time
from logger import get_logger

DEBUG = True if os.environ.get('DEBUG') is not None else False
DISCOVERY_ACK = 'IP_DISCOVERY_ACK'.encode()           # ACK for broadcast
DISCOVERY_OK = 'IP_DISCOVERY_OK'.encode()             # Not used yet
DISCOVERY_RSP_GTW = 'IP_DISCOVERY_RSP_GTW'.encode()   # RSP for gateway
DISCOVERY_RSP_MSH = 'IP_DISCOVERY_RSP_MSH'.encode()   # RSP for mesh
DISCOVERY_TIMEOUT = 0.5
SOCKET_TIMEOUT = 0.2
PORT_SERVER = 9434
PORT_CLIENT = 9435


def create_udp_socket():
  sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)
  sock.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
  sock.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
  return sock


def start_discovery_server():
  """Serves the UDP socket for UDP broadcast discovery"""
  logger = get_logger(__name__)
  sock = create_udp_socket()
  server_address = ('', PORT_SERVER)
  local_ip = FindMyIP.internal()

  try:
    sock.bind(server_address)
    logger.info("Started discovery socket")

    while True:
      data, addr = sock.recvfrom(4096)
      logger.debug(f"Received a packet from {addr}")
      logger.debug(f"{addr[0]} | {local_ip}")
      logger.debug(data)

      if str(addr[0]) == str(local_ip): continue
      logger.debug("IP accepted")

      if data == DISCOVERY_ACK:
        logger.debug("ACK accepted")
        sock.sendto(DISCOVERY_RSP_GTW, (addr[0], PORT_CLIENT))
        logger.debug(f"Send ACK to {addr}")

  except Exception as err:
    sock.close()
    logger.error(err)


def start_discovery_client():
  print("Started discovery client")
  sock = create_udp_socket()
  sock.settimeout(SOCKET_TIMEOUT)
  server_address = ('255.255.255.255', PORT_SERVER)
  start_time_stamp = get_unix_time()
  delta = round(get_unix_time() - start_time_stamp, 2)
  discovered_devices = []

  try:
    sock.bind(('', PORT_CLIENT))

    while delta <= DISCOVERY_TIMEOUT:
      delta = round(get_unix_time() - start_time_stamp, 2)
      sock.sendto(DISCOVERY_ACK, server_address)
      data, addr = sock.recvfrom(4096)

      if str(addr[0]) in discovered_devices: continue
      if data == DISCOVERY_RSP_GTW or data == DISCOVERY_RSP_MSH:
        discovered_devices.append(str(addr[0]))

  except Exception as err:
    print(err)

  finally:
    sock.close()
    return discovered_devices


devices = start_discovery_client()
print(f"Devices: {devices}")