#!/usr/bin/python3

from __future__ import absolute_import
from __future__ import print_function
import socket, time, os

if socket.gethostname()=="work.salstar.sk":
  default_sap_ip = '233.10.47.10'
else: # Antik
  default_sap_ip = '224.2.127.254'
sdp_dir = os.environ.get("SDP_DIR")

class multicast:
  def __init__(self, group=default_sap_ip, port=9875, join=True):
      self.group = group
      sock = socket.socket(
               socket.AF_INET,
               socket.SOCK_DGRAM,
               #socket.IPPROTO_UDP
             )
      self.sock = sock
      sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
      sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 32)
      sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 1)
      sock.bind((os.environ.get("SAP_BIND_IP", ""), port))
      self.host = socket.gethostbyname(socket.gethostname())
      sock.setsockopt(
        socket.SOL_IP, socket.IP_MULTICAST_IF,
        socket.inet_aton(self.host)
      )
      if join:
        sock.setsockopt(
          socket.SOL_IP, socket.IP_ADD_MEMBERSHIP,
          socket.inet_aton(group) + socket.inet_aton(self.host)
        )
      # functions
      self.recv = self.sock.recv
      self.recvfrom = self.sock.recvfrom
      self.send = self.sock.send
      self.sendall = self.sock.sendall
  def close(self):
      self.sock.setsockopt(
        socket.SOL_IP, socket.IP_DROP_MEMBERSHIP,
        socket.inet_aton(self.group) + socket.inet_aton(self.host)
      )
      self.sock.close()

class sdp(dict):
  def __init__(self, data):
      d0 = data[0]
      self.ver = d0>>5
      self.addr = (d0>>4)&1
      self.mtype = (d0>>2)&1
      self.encryption = (d0>>1)&1
      self.compress = d0&1
      self.auth_len = data[1]
      self.msg_id = data[2]*256+data[3]
      if self.addr==0:
        self.source = data[4:8]
        self.data = data[8:].rstrip(b'\n')
      else:
        self.source = data[4:20]
        self.data = data[20:].rstrip(b'\n')
      if b'\x00' in self.data:
        self.ctype, self.data = self.data.split(b'\x00', 1)
      else:
        self.ctype = b""
      if self.ver>=1:
        self.list = [
          x.rstrip(b'\r').decode("utf8").split('=', 1)
          for x in self.data.split(b'\n')
          if b'=' in x
        ]
        dict.__init__(self, **dict(self.list))
  def ok(self):
      if self.encryption:
        print("ENCRYPTED:", self)
      return self.ver==1 and self.addr==0 and self.mtype==0 \
             and self.encryption==0 and self.compress==0 \
             and self['s'] and ('m' in self) and ('c' in self)
  def name(self):
      return self['s']
  def filename(self):
      return self['s'].replace(" ", "_").replace("/", "_") + ".sdp"
  def ip(self):
      return self['c'].split(' ')[2].split('/', 1)[0]
  def port(self):
      return self['m'].split(' ')[1]
  def media(self):
      return self['m'].split(' ')[0]
  def url(self):
      return "rtp://%s:%s/" % (self.ip(), self.port())
  def group(self):
      return self.a('x-plgroup')
  def a(self, search):
      search = search+":"
      for key, value in self.list:
        if key=="a" and value.startswith(search):
          return value.split(":", 1)[1]
      return ''

def search(group=default_sap_ip, port=9875, timeout=5):
    mcast = multicast(group, port)
    all = []
    tend = time.time()+timeout
    while time.time()<tend:
      try:
        data, addr = mcast.recvfrom(1024)
        if data in all:
          continue
        all.append(data)
        d = sdp(data)
        if d.ok():
          if sdp_dir:
            open(os.path.join(sdp_dir, d.filename()), "wb").write(d.data)
          yield d
      except socket.error as e:
        print('Expection', e)
        break
    mcast.close()

if __name__ == '__main__':
  import sys
  if len(sys.argv)>1:
    ip = sys.argv[1]
  else:
    ip = default_sap_ip
  timeout = int(os.environ.get("TIMEOUT", "10"))
  if "--php" in sys.argv:
    print("<?php")
    for i, d in enumerate(sorted(search(ip, timeout=timeout), key=lambda x: x.url())):
      print('multicast("%s", "%s", "%s");' % (d.group(), d.name(), d.url()))
  else:
    print("CHANNELS = [")
    for i, d in enumerate(sorted(search(ip, timeout=timeout), key=lambda x: x.url())):
      print('  # %d.' % i)
      print('  multicast(u"%s", "%s", "%s"),' % (d.name(), d.url(), d.group()))
    print("]")