from types import FrameType
from typing import Any, List

from argparse import ArgumentParser
from django.core.management.base import BaseCommand
from django.conf import settings
from django.utils import autoreload
from zerver.worker.queue_processors import get_worker, get_active_worker_queues
import sys
import signal
import logging
import threading

class Command(BaseCommand):
    def add_arguments(self, parser):
        # type: (ArgumentParser) -> None
        parser.add_argument('--queue_name', metavar='<queue name>', type=str,
                            help="queue to process")
        parser.add_argument('--worker_num', metavar='<worker number>', type=int, nargs='?', default=0,
                            help="worker label")
        parser.add_argument('--all', dest="all", action="store_true", default=False,
                            help="run all queues")
        parser.add_argument('--multi_threaded', nargs='+',
                            metavar='<list of queue name>',
                            type=str, required=False,
                            help="list of queue to process")

    help = "Runs a queue processing worker"

    def handle(self, *args, **options):
        # type: (*Any, **Any) -> None
        logging.basicConfig()
        logger = logging.getLogger('process_queue')

        def exit_with_three(signal, frame):
            # type: (int, FrameType) -> None
            """
            This process is watched by Django's autoreload, so exiting
            with status code 3 will cause this process to restart.
            """
            logger.warning("SIGUSR1 received. Restarting this queue processor.")
            sys.exit(3)

        if not settings.USING_RABBITMQ:
            # Make the warning silent when running the tests
            if settings.TEST_SUITE:
                logger.info("Not using RabbitMQ queue workers in the test suite.")
            else:
                logger.error("Cannot run a queue processor when USING_RABBITMQ is False!")
            sys.exit(1)

        def run_threaded_workers(queues, logger):
            # type: (List[str], logging.Logger) -> None
            cnt = 0
            for queue_name in queues:
                if not settings.DEVELOPMENT:
                    logger.info('launching queue worker thread ' + queue_name)
                cnt += 1
                td = Threaded_worker(queue_name)
                td.start()
            assert len(queues) == cnt
            logger.info('%d queue worker threads were launched' % (cnt,))

        if options['all']:
            signal.signal(signal.SIGUSR1, exit_with_three)
            autoreload.main(run_threaded_workers, (get_active_worker_queues(), logger))
        elif options['multi_threaded']:
            signal.signal(signal.SIGUSR1, exit_with_three)
            queues = options['multi_threaded']
            autoreload.main(run_threaded_workers, (queues, logger))
        else:
            queue_name = options['queue_name']
            worker_num = options['worker_num']

            logger.info("Worker %d connecting to queue %s" % (worker_num, queue_name))
            worker = get_worker(queue_name)
            worker.setup()

            def signal_handler(signal, frame):
                # type: (int, FrameType) -> None
                logger.info("Worker %d disconnecting from queue %s" % (worker_num, queue_name))
                worker.stop()
                sys.exit(0)
            signal.signal(signal.SIGTERM, signal_handler)
            signal.signal(signal.SIGINT, signal_handler)
            signal.signal(signal.SIGUSR1, signal_handler)

            worker.start()

class Threaded_worker(threading.Thread):
    def __init__(self, queue_name):
        # type: (str) -> None
        threading.Thread.__init__(self)
        self.worker = get_worker(queue_name)

    def run(self):
        # type: () -> None
        self.worker.setup()
        logging.debug('starting consuming ' + self.worker.queue_name)
        self.worker.start()