from __future__ import absolute_import

from typing import Any

from argparse import ArgumentParser
from django.core.management.base import BaseCommand
from django.core.management import CommandError
from django.conf import settings
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")

    help = "Runs a queue processing worker"
    def handle(self, *args, **options):
        # type: (*Any, **Any) -> None
        logging.basicConfig()
        logger = logging.getLogger('process_queue')

        if not settings.USING_RABBITMQ:
            logger.error("Cannot run a queue processor when USING_RABBITMQ is False!")
            sys.exit(1)

        if options['all']:
            for queue_name in get_active_worker_queues():
                logger.info('launching queue worker thread ' + queue_name)
                td = Threaded_worker(queue_name)
                td.start()
        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):
                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)

            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()