#!/usr/bin/python2.7

""" DAB Streamer for Enigma2 using tsniv2ni and modified ni2http """

import os
import sys
import time
import atexit
import socket
import signal
import select

from signal import SIGTERM
 
from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler
from SocketServer import ThreadingMixIn
from urllib import unquote
from subprocess import Popen, PIPE

HOST_NAME = ""
PORT_NUMBER = 5237

def Stream(s, parameters):
    # construct the cmd
    tool = parameters[0]
    if tool == "tsniv2ni":
	_, sref, pid, sid = parameters
    	cmd = "wget http://127.0.0.1:8001/%s -q -O- | tsniv2ni %s | ni2out --sid %s" % (sref, pid, sid)
    elif tool == "ts2na":
        _, sref, pid, ofst, sid = parameters
        cmd = "wget http://127.0.0.1:8001/%s -q -O- | ts2na -p %s -s %s | na2ni | ni2out --sid %s" % (sref, pid, ofst, sid)
    elif tool == "ts2ni":
        _, sref, pid, ofst, sid = parameters
        cmd = "wget http://127.0.0.1:8001/%s -q -O- | ts2na -p %s -s %s | ni2out --sid %s" % (sref, pid, ofst, sid)
    elif tool == "fedi2eti":
        _, sref, pid, ip, port, sid = parameters
        cmd = "wget http://127.0.0.1:8001/%s -q -O- | fedi2eti %s %s %s | ni2out --sid %s" % (sref, pid, ip, port, sid)
    elif tool in  ("mpe2aac", "mpe2mpa"):
        _, sref, pid, ip, port = parameters
        cmd = "wget http://127.0.0.1:8001/%s -q -O- | %s %s %s %s" % (sref, tool, pid, ip, port)
    elif tool == "ott":
        _, sref, pid, ip, port = parameters
        cmd = "wget http://127.0.0.1:8001/%s -q -O- | dvb-ip-mpe2ts -i - -o - -p %s -a %s -n %s 2>/dev/null" % (sref, pid, ip, port)
    else:
        raise Exception("Unkown tool %s..." % tool)
    s.log_message("Using command %s", cmd)

    # run the shell as a subprocess:
    p = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE, shell=True, preexec_fn=os.setsid)

    try:
        Streamer(s.wfile, p.stdout)
    except socket.error as se:
        s.log_message("Got Socket Exception %s", se)
    except Exception as e:
        s.log_message("Got Exception: %s", e)
    else:
        s.wfile.close()
    finally:
        s.rfile.close()
        p.terminate()
        p.kill()
        os.killpg(os.getpgid(p.pid), signal.SIGTERM)  # Send the signal to all the process groups

def Streamer(wfile, stdout):
    # get the output
    while True:
        reads, _, _ = select.select([stdout], [], [], 30)
        if reads:
            buff = stdout.read(4096)
            if not buff:
                break
            wfile.write(buff)
        else:
            raise Exception('Timeout....')

class StreamHandler(BaseHTTPRequestHandler):

    def do_HEAD(s):
        s.send_response(200)
        s.send_header("Server", "DAB+ Streamer")
        s.send_header("Content-type", "text/html")
        s.end_headers()

    def do_GET(s):
        """Respond to a GET request."""
        s.send_response(200)
        s.send_header("Server", "DAB+ Streamer")
        s.send_header("Content-type", "text/html")
        s.end_headers()

        try:
            parameters = tuple(unquote(s.path[1:]).split("/"))
            s.log_message("Parameters: %s", s.path)
            Stream(s, parameters)
        except Exception as e:
            s.log_message("Exception occured when streaming %s", e)

    # https://stackoverflow.com/questions/6063416/python-basehttpserver-how-do-i-catch-trap-broken-pipe-errors
    def finish(self, *args, **kw):
        try:
            if not self.wfile.closed:
                self.wfile.flush()
                self.wfile.close()
        except socket.error:
            pass
        self.rfile.close()

    def handle(self):
        try:
            BaseHTTPRequestHandler.handle(self)
        except socket.error:
            pass


class ThreadedHTTPServer(ThreadingMixIn, HTTPServer):
    """Handle requests in a separate thread."""


def start():
    httpd = ThreadedHTTPServer((HOST_NAME, PORT_NUMBER), StreamHandler)
    print time.asctime(), "Server Starts - %s:%s" % (HOST_NAME, PORT_NUMBER)
    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        pass
    httpd.server_close()
    print time.asctime(), "Server Stops - %s:%s" % (HOST_NAME, PORT_NUMBER)


class Daemon:
	"""
	A generic daemon class.
	
	Usage: subclass the Daemon class and override the run() method
	"""
	def __init__(self, pidfile, stdin="/dev/null", stdout="/dev/null", stderr="/dev/null"):
		self.stdin = stdin
		self.stdout = stdout
		self.stderr = stderr
		self.pidfile = pidfile
	
	def daemonize(self):
		"""
		do the UNIX double-fork magic, see Stevens' "Advanced 
		Programming in the UNIX Environment" for details (ISBN 0201563177)
		http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16
		"""
		try: 
			pid = os.fork() 
			if pid > 0:
				# exit first parent
				sys.exit(0) 
		except OSError, e: 
			sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
			sys.exit(1)
	
		# decouple from parent environment
		os.chdir("/") 
		os.setsid() 
		os.umask(0) 
	
		# do second fork
		try: 
			pid = os.fork() 
			if pid > 0:
				# exit from second parent
				sys.exit(0) 
		except OSError, e: 
			sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
			sys.exit(1) 
	
		# redirect standard file descriptors
		sys.stdout.flush()
		sys.stderr.flush()
		si = file(self.stdin, "r")
		so = file(self.stdout, "a+")
		se = file(self.stderr, "a+", 0)
		os.dup2(si.fileno(), sys.stdin.fileno())
		os.dup2(so.fileno(), sys.stdout.fileno())
		os.dup2(se.fileno(), sys.stderr.fileno())
	
		# write pidfile
		atexit.register(self.delpid)
		pid = str(os.getpid())
		file(self.pidfile,"w+").write("%s\n" % pid)
	
	def delpid(self):
		os.remove(self.pidfile)

	def start(self):
		"""
		Start the daemon
		"""
		# Check for a pidfile to see if the daemon already runs
		try:
			pf = file(self.pidfile,"r")
			pid = int(pf.read().strip())
			pf.close()
		except IOError:
			pid = None
	
		if pid:
			message = "pidfile %s already exist. Daemon already running?\n"
			sys.stderr.write(message % self.pidfile)
			sys.exit(1)
		
		# Start the daemon
		self.daemonize()
		self.run()

	def stop(self):
		"""
		Stop the daemon
		"""
		# Get the pid from the pidfile
		try:
			pf = file(self.pidfile,"r")
			pid = int(pf.read().strip())
			pf.close()
		except IOError:
			pid = None
	
		if not pid:
			message = "pidfile %s does not exist. Daemon not running?\n"
			sys.stderr.write(message % self.pidfile)
			return # not an error in a restart

		# Try killing the daemon process	
		try:
			while 1:
				os.kill(pid, SIGTERM)
				time.sleep(0.1)
		except OSError, err:
			err = str(err)
			if err.find("No such process") > 0:
				if os.path.exists(self.pidfile):
					os.remove(self.pidfile)
			else:
				print str(err)
				sys.exit(1)

	def restart(self):
		"""
		Restart the daemon
		"""
		self.stop()
		self.start()

	def run(self):
		"""
		You should override this method when you subclass Daemon. It will be called after the process has been
		daemonized by start() or restart().
		"""


class DabStreamerDaemon(Daemon):
    def run(self):
        start()


if __name__ == "__main__":
    daemon = DabStreamerDaemon("/var/run/dabstreamer.pid")
    if len(sys.argv) == 2:
        if "start" == sys.argv[1]:
            daemon.start()
        elif "stop" == sys.argv[1]:
            daemon.stop()
        elif "restart" == sys.argv[1]:
            daemon.restart()
        elif "manualstart" == sys.argv[1]:
            start()
        else:
            print "Unknown command"
            sys.exit(2)
        sys.exit(0)
    else:
        print "usage: %s start|stop|restart|manualstart" % sys.argv[0]
        sys.exit(2)

