#!/usr/bin/python

import os
import sys
import pwd
import errno
import argparse
import time
import configobj
import validate
import subprocess
import threading
import daemon
# workaround for python-daemon >= 1.6
try:
    import daemon.pidlockfile as pidfile
except ImportError:
    import daemon.pidfile as pidfile

class Thread(threading.Thread):

    def __init__(self):
        threading.Thread.__init__(self)
        self.setDaemon(True)


class FetcherThread(Thread):
    """ Run py-i2phosts-fetcher periodically """

    def run(self):
        while True:
            run_prog('py-i2phosts-fetcher')
            time.sleep(float(config['fetch_interval']))


class CheckerThread(Thread):
    """ Run py-i2phosts-checker, py-i2phosts-maint, py-i2phosts-builder periodically """

    def run(self):
        while True:
            run_prog('py-i2phosts-checker')
            run_prog('py-i2phosts-maint')
            run_prog('py-i2phosts-builder')
            time.sleep(float(config['check_interval']))


def run_prog(prog):
    try:
        log.info('starting: %s', prog)
        sp_args = [prog]
        if args.debug or args.verbose:
            sp_args.append('-d')
        p = subprocess.Popen(sp_args, shell=False)
    except OSError, e:
        log.error('failed to exec %s: %s', prog, e)
        if e.errno == errno.ENOENT:
            log.error('   maybe it isn\'t in PATH?')
    else:
        p.wait()
        log.info('finished: %s', prog)


def main():
    def run_fetcher():
        fetcher = FetcherThread()
        fetcher.start()
        return fetcher

    def run_checker():
        checker = CheckerThread()
        checker.start()
        return checker

    # if we're just started, wait while fetcher get some new hosts
    fetcher = run_fetcher()
    log.debug('just started, delaying checker run for 300 secs')
    fetcher.join(300) # wait for 5 mins
    # start checker and other
    checker = run_checker()

    while True:
        log.debug('checking fetcher and checker threads status')
        if fetcher.isAlive() == False:
            log.warning('fetcher thread is dead, respawning...')
            fetcher = run_fetcher()
        else:
            log.debug('fetcher thread: alive')
        if checker.isAlive() == False:
            log.warning('checker thread is dead, respawning...')
            checker = run_checker()
        else:
            log.debug('checker thread: alive')
        # do check every 30 mins
        time.sleep(1800)

# parse command line options
parser = argparse.ArgumentParser(
        description='Master daemon for py-i2phosts.',
        epilog='Report bugs to https://github.com/i2phosts/py-i2phosts/issues')
parser.add_argument('-d', '--debug', action='store_true',
        help='run in debug mode without detaching from terminal'),
parser.add_argument('-v', '--verbose', action='store_true',
        help='run in verbose mode without detaching from terminal'),
parser.add_argument('-c', '--config', default='/etc/py-i2phosts/master.conf', dest='config_file',
        help='config file to use')
args = parser.parse_args()

# read and validate config
spec = '''
    log_file = string(default='/var/log/py-i2phosts/master.log')
    log_level = option('debug', 'info', 'warning', 'error', 'critical', default='info')
    pid_file = string(default='/var/run/py-i2phosts/master.pid')
    runas = string(default='_pyi2phosts')
    check_interval = integer(default=43200)
    fetch_interval = integer(default=1800)
    '''
spec = spec.split('\n')
config = configobj.ConfigObj(args.config_file, configspec=spec)
if 'include' in config:
    config_included = configobj.ConfigObj(config['include'])
    config.merge(config_included)

# django setup
DJANGO_SETTINGS_MODULE = 'pyi2phosts.settings'
if 'DJANGO_PROJECT_PATH' in config:
    DJANGO_PROJECT_PATH = config['DJANGO_PROJECT_PATH']
else:
    DJANGO_PROJECT_PATH = os.path.dirname(sys.argv[0]) + '/..'
sys.path.insert(1, DJANGO_PROJECT_PATH)
os.environ['DJANGO_SETTINGS_MODULE'] = DJANGO_SETTINGS_MODULE
import django
django.setup()
from pyi2phosts.lib.utils import get_logger
from pyi2phosts.lib.utils import validate_config

# validate config
validate_config(config)

# configure logger
if args.debug == True:
    log_level = 'debug'
    log_file = None
elif args.verbose == True:
    log_level = 'info'
    log_file = None
else:
    log_level = config['log_level']
    log_file = config['log_file']

if not args.debug and not args.verbose:
    # get pid object for daemon
    pid = pidfile.TimeoutPIDLockFile(config['pid_file'], 10)
    # create daemon context
    d = daemon.DaemonContext(pidfile=pid, umask=022)
    # write stderr to logfile # FIXME: and how we will deal with log rotation?
    logfile = open(config['log_file'], 'a')
    d.stderr = logfile
    d.stdout = logfile
    # drop privileges when started as root
    if os.getuid() == 0:
        runas = config['runas']
        pw_entry = pwd.getpwnam(runas)
        d.uid = pw_entry[2]
        d.gid = pw_entry[3]
    os.chown(config['log_file'], d.uid, d.gid)
    d.open() # become daemon
log = get_logger(filename=log_file, log_level=log_level)
log.info('started')
main()