#!/usr/bin/env python3
# This file is placed in the Public Domain.


"daemon"


import getpass
import os
import pathlib
import pwd
import sys


from nixt.modules import face
from nixt.persist import Workdir
from nixt.runtime import errors, forever, init 


from nixt import NAME

def daemon(verbose=False):
    "switch to background."
    pid = os.fork()
    if pid != 0:
        os._exit(0)
    os.setsid()
    pid2 = os.fork()
    if pid2 != 0:
        os._exit(0)
    if not verbose:
        with open('/dev/null', 'r', encoding="utf-8") as sis:
            os.dup2(sis.fileno(), sys.stdin.fileno())
        with open('/dev/null', 'a+', encoding="utf-8") as sos:
            os.dup2(sos.fileno(), sys.stdout.fileno())
        with open('/dev/null', 'a+', encoding="utf-8") as ses:
            os.dup2(ses.fileno(), sys.stderr.fileno())
    os.umask(0)
    os.chdir("/")
    os.nice(10)


def pidfile(name):
    "write the pid to a file."
    pidfile = os.path.join(Workdir.wdr, f"{name}.pid")
    if os.path.exists(pidfile):
        os.unlink(pidfile)
    path = pathlib.Path(pidfile)
    path.parent.mkdir(parents=True, exist_ok=True)
    with open(pidfile, "w", encoding="utf-8") as fds:
        fds.write(str(os.getpid()))


def privileges(username):
    "drop privileges."
    pwnam = pwd.getpwnam(username)
    os.setgid(pwnam.pw_gid)
    os.setuid(pwnam.pw_uid)


def main():
    "main"
    daemon(True)
    privileges(getpass.getuser())
    pidfile(NAME)
    init(face)
    forever()


if __name__ == "__main__":
    main()
