"""Generic linux daemon base class for python 3.x."""
import uuid
import sys
import os
import time
import threading


class daemon(object):
    """A generic daemon class.

    Usage: subclass the daemon class and override the run() method."""

    def __init__(self):
        self._thread = threading.Thread(target=self.test, name='task_queue', daemon=True)

    def test(self):
        for i in range(3):
            print('running loop %s' % i)
            time.sleep(1)

    def daemonize(self):
        """Daemonizes the current process. Returns the new pid"""
        try:
            pid = os.fork()
            if pid > 0:
                # exit first parent
                sys.exit(0)
        except OSError as err:
            sys.stderr.write('fork #1 failed: {0}\n'.format(err))
            sys.exit(1)

        # decouple from parent environment
        os.chdir('/')
        os.setsid()
        os.umask(0)

        print('First fork pid %s' % os.getpid())

        # do second fork
        try:
            pid = os.fork()
            if pid > 0:
                # exit from second parent
                sys.exit(0)
        except OSError as err:
            sys.stderr.write('fork #2 failed: {0}\n'.format(err))
            sys.exit(1)

        # redirect standard file descriptors
        sys.stdout.flush()
        sys.stderr.flush()
        si = open(os.devnull, 'r')
        so = open('/tmp/file', 'a+')
        se = open('/tmp/file', 'a+')

        os.dup2(si.fileno(), sys.stdin.fileno())
        os.dup2(so.fileno(), sys.stdout.fileno())
        os.dup2(se.fileno(), sys.stderr.fileno())

    def start(self):
        """Start the daemon."""
        # Start the daemon
        self.daemonize()
        self._thread.start()
        self.wait()

    def wait(self):
        """
        Waits for the thread to exit.
        Allows abortion of task queue with ctrl-c
        """
        try:
            print('thread alive is %s' % self._thread.is_alive())
            while self._thread.is_alive():
                print('pid %s wait sleep thread alive is %s' % (os.getpid(), self._thread.is_alive()))
                time.sleep(0.5)
        except KeyboardInterrupt:
            print('Got ctrl-c, shutting down after running task (if any) completes')
            # We still wait to finish cleanly, pressing ctrl-c again will abort
            while self._thread.is_alive():
                time.sleep(0.5)

d = daemon()
d.start()