#!/usr/bin/env python3
import argparse
import configparser
import logging
import os
import pwd
import shlex
import subprocess
import sys
import time

sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
from scripts.lib.zulip_tools import DEPLOYMENTS_DIR, ENDC, OKGREEN, WARNING, overwrite_symlink

logging.Formatter.converter = time.gmtime
logging.basicConfig(format="%(asctime)s restart-server: %(message)s",
                    level=logging.INFO)

parser = argparse.ArgumentParser()
parser.add_argument('--fill-cache', action='store_true',
                    help='Fill the memcached caches')
args = parser.parse_args()

deploy_path = os.path.realpath(os.path.join(os.path.dirname(__file__), '..'))
os.chdir(deploy_path)

if pwd.getpwuid(os.getuid()).pw_name != "zulip":
    logging.error("Must be run as user 'zulip'.")
    sys.exit(1)

# Send a statsd event on restarting the server
subprocess.check_call(["./manage.py", "send_stats", "incr", "events.server_restart", str(int(time.time()))])

if args.fill_cache:
    logging.info("Filling memcached caches")
    subprocess.check_call(["./manage.py", "fill_memcached_caches"])

core_server_services = ["zulip-django"]
if os.path.exists("/etc/supervisor/conf.d/thumbor.conf"):
    core_server_services.append("zulip-thumbor")

current_symlink = os.path.join(DEPLOYMENTS_DIR, "current")
last_symlink = os.path.join(DEPLOYMENTS_DIR, "last")
change_symlink = os.readlink(current_symlink) != deploy_path
if change_symlink:
    overwrite_symlink(os.readlink(current_symlink), last_symlink)
    overwrite_symlink(deploy_path, current_symlink)

config_file = configparser.RawConfigParser()
config_file.read("/etc/zulip/zulip.conf")

try:
    tornado_processes = int(config_file.get('application_server', 'tornado_processes'))
except (configparser.NoSectionError, configparser.NoOptionError):
    tornado_processes = 1

# We restart just the zulip-tornado service early, in order to
# minimize downtime of the tornado service caused by too many Python
# processes restarting at the same time resulting in it receiving
# insufficient priority.  This is important, because Tornado is the
# main source of user-visible downtime when we restart a Zulip server.
if tornado_processes > 1:
    for p in range(9800, 9800+tornado_processes):
        # Restart Tornado processes individually for a better rate of
        # restarts.  This also avoids behavior with restarting a whole
        # supervisord group where if any individual process is slow to
        # stop, the whole bundle stays stopped for an extended time.
        logging.info("Restarting Tornado process on port %s", p)
        subprocess.check_call(["supervisorctl", "restart", f"zulip-tornado:zulip-tornado-port-{p}"])
else:
    logging.info("Restarting Tornado process")
    subprocess.check_call(["supervisorctl", "restart", "zulip-tornado", "zulip-tornado:*"])

# Restart the uWSGI and related processes via supervisorctl.
logging.info("Stopping workers")
subprocess.check_call(["supervisorctl", "stop", "zulip-workers:*"])
logging.info("Stopping server core")
subprocess.check_call(["supervisorctl", "stop", *core_server_services])

logging.info("Starting server core")
subprocess.check_call(["supervisorctl", "start", *reversed(core_server_services)])
logging.info("Starting workers")
subprocess.check_call(["supervisorctl", "start", "zulip-workers:*"])

using_sso = subprocess.check_output(['./scripts/get-django-setting', 'USING_APACHE_SSO'])
if using_sso.strip() == b'True':
    logging.info("Restarting Apache WSGI process...")
    subprocess.check_call(["pkill", "-f", "apache2", "-u", "zulip"])

if os.path.exists("/etc/supervisor/conf.d/zulip_db.conf"):
    subprocess.check_call(["supervisorctl", "restart", "process-fts-updates"])

logging.info("Done!")
print(OKGREEN + "Application restarted successfully!" + ENDC)

if change_symlink and "PWD" in os.environ:
    for symlink in [last_symlink, current_symlink]:
        if os.path.commonprefix([os.environ["PWD"], symlink]) == symlink:
            print(
                """
{}Your shell entered its current directory through a symlink:
  {}
which has now changed. Your shell will not see this change until you run:
  cd {}
to traverse the symlink again.{}
""".format(WARNING, symlink, shlex.quote(os.environ["PWD"]), ENDC),
                file=sys.stderr,
            )