#!/usr/bin/env python

""" xos-policy.py

    Standalone interface to model_policy engine.

    Normally model policies are run by the synchronizer. This file allows them to be run independently as an aid
    to development.
"""

import os
import argparse
import sys

sys.path.append('/opt/xos')

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "xos.settings")
from xos.config import Config, DEFAULT_CONFIG_FN
from xos.logger import Logger, logging, logger
import time
from synchronizers.new_base.model_policy_loop import XOSPolicyEngine
from synchronizers.new_base.modelaccessor import *

config = Config()

logger = Logger(level=logging.INFO)

# after http://www.erlenstar.demon.co.uk/unix/faq_2.html
def daemon():
    """Daemonize the current process."""
    if os.fork() != 0: os._exit(0)
    os.setsid()
    if os.fork() != 0: os._exit(0)
    os.umask(0)
    devnull = os.open(os.devnull, os.O_RDWR)
    os.dup2(devnull, 0)
    # xxx fixme - this is just to make sure that nothing gets stupidly lost - should use devnull
    logdir=os.path.dirname(config.observer_logfile)
    # when installed in standalone we might not have httpd installed
    if not os.path.isdir(logdir): os.mkdir(logdir)
    crashlog = os.open('%s'%config.observer_logfile, os.O_RDWR | os.O_APPEND | os.O_CREAT, 0644)
    os.dup2(crashlog, 1)
    os.dup2(crashlog, 2)

    if hasattr(config, "observer_pidfile"):
        pidfile = config.get("observer_pidfile")
    else:
        pidfile = "/var/run/xosobserver.pid"
    try:
        file(pidfile,"w").write(str(os.getpid()))
    except:
        print "failed to create pidfile %s" % pidfile

def main():
    # Generate command line parser
    parser = argparse.ArgumentParser(usage='%(prog)s [options]')
    parser.add_argument('-d', '--daemon', dest='daemon', action='store_true', default=False,
                        help='Run as daemon.')
    # smbaker: util/config.py parses sys.argv[] directly to get config file name; include the option here to avoid
    #   throwing unrecognized argument exceptions
    parser.add_argument('-C', '--config', dest='config_file', action='store', default=DEFAULT_CONFIG_FN,
                        help='Name of config file.')
    args = parser.parse_args()

    if args.daemon: daemon()

    models_active = False
    wait = False
    while not models_active:
        try:
            _ = Instance.objects.first()
            _ = NetworkTemplate.objects.first()
            models_active = True
        except Exception,e:
            logger.info(str(e))
            logger.info('Waiting for data model to come up before starting...')
            time.sleep(10)
            wait = True

    if (wait):
        time.sleep(60) # Safety factor, seeing that we stumbled waiting for the data model to come up.

    # start model policies thread
    policies_dir = Config().observer_model_policies_dir

    XOSPolicyEngine(policies_dir=policies_dir).run()

if __name__ == '__main__':
    main()