import os
import time
import ujson
import smtplib
import re

from django.conf import settings
from django.test import override_settings
from mock import patch, MagicMock
from typing import Any, Callable, Dict, List, Mapping, Tuple

from zerver.lib.email_mirror import RateLimitedRealmMirror
from zerver.lib.email_mirror_helpers import encode_email_address
from zerver.lib.rate_limiter import RateLimiterLockingException, clear_history
from zerver.lib.send_email import FromAddress
from zerver.lib.test_helpers import simulated_queue_client
from zerver.lib.test_classes import ZulipTestCase
from zerver.models import get_client, UserActivity, PreregistrationUser, \
    get_system_bot, get_stream, get_realm
from zerver.worker import queue_processors
from zerver.worker.queue_processors import (
    get_active_worker_queues,
    QueueProcessingWorker,
    EmailSendingWorker,
    LoopQueueProcessingWorker,
    MissedMessageWorker,
    SlowQueryWorker,
)

from zerver.middleware import write_log_line

Event = Dict[str, Any]

# This is used for testing LoopQueueProcessingWorker, which
# would run forever if we don't mock time.sleep to abort the
# loop.
class AbortLoop(Exception):
    pass

class WorkerTest(ZulipTestCase):
    class FakeClient:
        def __init__(self) -> None:
            self.consumers = {}  # type: Dict[str, Callable[[Dict[str, Any]], None]]
            self.queue = []  # type: List[Tuple[str, Any]]

        def register_json_consumer(self,
                                   queue_name: str,
                                   callback: Callable[[Dict[str, Any]], None]) -> None:
            self.consumers[queue_name] = callback

        def start_consuming(self) -> None:
            for queue_name, data in self.queue:
                callback = self.consumers[queue_name]
                callback(data)
            self.queue = []

        def drain_queue(self, queue_name: str, json: bool) -> List[Event]:
            assert json
            events = [
                dct
                for (queue_name, dct)
                in self.queue
            ]

            # IMPORTANT!
            # This next line prevents us from double draining
            # queues, which was a bug at one point.
            self.queue = []

            return events

    @override_settings(SLOW_QUERY_LOGS_STREAM="errors")
    def test_slow_queries_worker(self) -> None:
        error_bot = get_system_bot(settings.ERROR_BOT)
        fake_client = self.FakeClient()
        worker = SlowQueryWorker()

        time_mock = patch(
            'zerver.worker.queue_processors.time.sleep',
            side_effect=AbortLoop,
        )

        send_mock = patch(
            'zerver.worker.queue_processors.internal_send_message'
        )

        with send_mock as sm, time_mock as tm:
            with simulated_queue_client(lambda: fake_client):
                try:
                    worker.setup()
                    # `write_log_line` is where we publish slow queries to the queue.
                    with patch('zerver.middleware.is_slow_query', return_value=True):
                        write_log_line(log_data=dict(test='data'), email='test@zulip.com',
                                       remote_ip='127.0.0.1', client_name='website', path='/test/',
                                       method='GET')
                    worker.start()
                except AbortLoop:
                    pass

        self.assertEqual(tm.call_args[0][0], 60)  # should sleep 60 seconds

        sm.assert_called_once()
        args = [c[0] for c in sm.call_args_list][0]
        self.assertEqual(args[0], error_bot.realm)
        self.assertEqual(args[1], error_bot.email)
        self.assertEqual(args[2], "stream")
        self.assertEqual(args[3], "errors")
        self.assertEqual(args[4], "testserver: slow queries")
        # Testing for specific query times can lead to test discrepancies.
        logging_info = re.sub(r'\(db: [0-9]+ms/13q\)', '', args[5])
        self.assertEqual(logging_info, '    127.0.0.1       GET     200 -1000ms '
                                       ' /test/ (test@zulip.com via website) (test@zulip.com)\n')

    def test_missed_message_worker(self) -> None:
        cordelia = self.example_user('cordelia')
        hamlet = self.example_user('hamlet')
        othello = self.example_user('othello')

        hamlet1_msg_id = self.send_personal_message(
            from_email=cordelia.email,
            to_email=hamlet.email,
            content='hi hamlet',
        )

        hamlet2_msg_id = self.send_personal_message(
            from_email=cordelia.email,
            to_email=hamlet.email,
            content='goodbye hamlet',
        )

        hamlet3_msg_id = self.send_personal_message(
            from_email=cordelia.email,
            to_email=hamlet.email,
            content='hello again hamlet',
        )

        othello_msg_id = self.send_personal_message(
            from_email=cordelia.email,
            to_email=othello.email,
            content='where art thou, othello?',
        )

        events = [
            dict(user_profile_id=hamlet.id, message_id=hamlet1_msg_id),
            dict(user_profile_id=hamlet.id, message_id=hamlet2_msg_id),
            dict(user_profile_id=othello.id, message_id=othello_msg_id),
        ]

        fake_client = self.FakeClient()
        for event in events:
            fake_client.queue.append(('missedmessage_emails', event))

        mmw = MissedMessageWorker()

        class MockTimer():
            is_running = False

            def is_alive(self) -> bool:
                return self.is_running

            def start(self) -> None:
                self.is_running = True

            def cancel(self) -> None:
                self.is_running = False

        timer = MockTimer()
        time_mock = patch(
            'zerver.worker.queue_processors.Timer',
            return_value=timer,
        )

        send_mock = patch(
            'zerver.lib.email_notifications.do_send_missedmessage_events_reply_in_zulip'
        )
        mmw.BATCH_DURATION = 0

        bonus_event = dict(user_profile_id=hamlet.id, message_id=hamlet3_msg_id)

        with send_mock as sm, time_mock as tm:
            with simulated_queue_client(lambda: fake_client):
                self.assertFalse(timer.is_alive())
                mmw.setup()
                mmw.start()
                self.assertTrue(timer.is_alive())
                fake_client.queue.append(('missedmessage_emails', bonus_event))

                # Double-calling start is our way to get it to run again
                self.assertTrue(timer.is_alive())
                mmw.start()

                # Now, we actually send the emails.
                mmw.maybe_send_batched_emails()
                self.assertFalse(timer.is_alive())

        self.assertEqual(tm.call_args[0][0], 5)  # should sleep 5 seconds

        args = [c[0] for c in sm.call_args_list]
        arg_dict = {
            arg[0].id: dict(
                missed_messages=arg[1],
                count=arg[2],
            )
            for arg in args
        }

        hamlet_info = arg_dict[hamlet.id]
        self.assertEqual(hamlet_info['count'], 3)
        self.assertEqual(
            {m['message'].content for m in hamlet_info['missed_messages']},
            {'hi hamlet', 'goodbye hamlet', 'hello again hamlet'},
        )

        othello_info = arg_dict[othello.id]
        self.assertEqual(othello_info['count'], 1)
        self.assertEqual(
            {m['message'].content for m in othello_info['missed_messages']},
            {'where art thou, othello?'}
        )

    @patch('zerver.worker.queue_processors.mirror_email')
    def test_mirror_worker(self, mock_mirror_email: MagicMock) -> None:
        fake_client = self.FakeClient()
        stream = get_stream('Denmark', get_realm('zulip'))
        stream_to_address = encode_email_address(stream)
        data = [
            dict(
                message=u'\xf3test',
                time=time.time(),
                rcpt_to=stream_to_address
            )
        ] * 3
        for element in data:
            fake_client.queue.append(('email_mirror', element))

        with simulated_queue_client(lambda: fake_client):
            worker = queue_processors.MirrorWorker()
            worker.setup()
            worker.start()

        self.assertEqual(mock_mirror_email.call_count, 3)

    @patch('zerver.lib.rate_limiter.logger.warning')
    @patch('zerver.worker.queue_processors.mirror_email')
    @override_settings(RATE_LIMITING_MIRROR_REALM_RULES=[(10, 2)])
    def test_mirror_worker_rate_limiting(self, mock_mirror_email: MagicMock,
                                         mock_warn: MagicMock) -> None:
        fake_client = self.FakeClient()
        realm = get_realm('zulip')
        clear_history(RateLimitedRealmMirror(realm))
        stream = get_stream('Denmark', realm)
        stream_to_address = encode_email_address(stream)
        data = [
            dict(
                message=u'\xf3test',
                time=time.time(),
                rcpt_to=stream_to_address
            )
        ] * 5
        for element in data:
            fake_client.queue.append(('email_mirror', element))

        with simulated_queue_client(lambda: fake_client):
            start_time = time.time()
            with patch('time.time', return_value=start_time):
                worker = queue_processors.MirrorWorker()
                worker.setup()
                worker.start()
                # Of the first 5 messages, only 2 should be processed
                # (the rest being rate-limited):
                self.assertEqual(mock_mirror_email.call_count, 2)

                # If a new message is sent into the stream mirror, it will get rejected:
                fake_client.queue.append(('email_mirror', data[0]))
                worker.start()
                self.assertEqual(mock_mirror_email.call_count, 2)

                # However, missed message emails don't get rate limited:
                with self.settings(EMAIL_GATEWAY_PATTERN="%s@example.com"):
                    address = 'mm' + ('x' * 32) + '@example.com'
                    event = dict(
                        message=u'\xf3test',
                        time=time.time(),
                        rcpt_to=address
                    )
                    fake_client.queue.append(('email_mirror', event))
                    worker.start()
                    self.assertEqual(mock_mirror_email.call_count, 3)

            # After some times passes, emails get accepted again:
            with patch('time.time', return_value=(start_time + 11.0)):
                fake_client.queue.append(('email_mirror', data[0]))
                worker.start()
                self.assertEqual(mock_mirror_email.call_count, 4)

                # If RateLimiterLockingException is thrown, we rate-limit the new message:
                with patch('zerver.lib.rate_limiter.incr_ratelimit',
                           side_effect=RateLimiterLockingException):
                    fake_client.queue.append(('email_mirror', data[0]))
                    worker.start()
                    self.assertEqual(mock_mirror_email.call_count, 4)
                    expected_warn = "Deadlock trying to incr_ratelimit for RateLimitedRealmMirror:zulip"
                    mock_warn.assert_called_with(expected_warn)

    def test_email_sending_worker_retries(self) -> None:
        """Tests the retry_send_email_failures decorator to make sure it
        retries sending the email 3 times and then gives up."""
        fake_client = self.FakeClient()

        data = {
            'template_prefix': 'zerver/emails/confirm_new_email',
            'to_emails': [self.example_email("hamlet")],
            'from_name': 'Zulip Account Security',
            'from_address': FromAddress.NOREPLY,
            'context': {}
        }
        fake_client.queue.append(('email_senders', data))

        def fake_publish(queue_name: str,
                         event: Dict[str, Any],
                         processor: Callable[[Any], None]) -> None:
            fake_client.queue.append((queue_name, event))

        with simulated_queue_client(lambda: fake_client):
            worker = queue_processors.EmailSendingWorker()
            worker.setup()
            with patch('zerver.lib.send_email.build_email',
                       side_effect=smtplib.SMTPServerDisconnected), \
                    patch('zerver.lib.queue.queue_json_publish',
                          side_effect=fake_publish), \
                    patch('logging.exception'):
                worker.start()

        self.assertEqual(data['failed_tries'], 4)

    def test_signups_worker_retries(self) -> None:
        """Tests the retry logic of signups queue."""
        fake_client = self.FakeClient()

        user_id = self.example_user('hamlet').id
        data = {'user_id': user_id, 'id': 'test_missed'}
        fake_client.queue.append(('signups', data))

        def fake_publish(queue_name: str, event: Dict[str, Any], processor: Callable[[Any], None]) -> None:
            fake_client.queue.append((queue_name, event))

        fake_response = MagicMock()
        fake_response.status_code = 400
        fake_response.text = ujson.dumps({'title': ''})
        with simulated_queue_client(lambda: fake_client):
            worker = queue_processors.SignupWorker()
            worker.setup()
            with patch('zerver.worker.queue_processors.requests.post',
                       return_value=fake_response), \
                    patch('zerver.lib.queue.queue_json_publish',
                          side_effect=fake_publish), \
                    patch('logging.info'), \
                    self.settings(MAILCHIMP_API_KEY='one-two',
                                  PRODUCTION=True,
                                  ZULIP_FRIENDS_LIST_ID='id'):
                worker.start()

        self.assertEqual(data['failed_tries'], 4)

    def test_signups_worker_existing_member(self) -> None:
        fake_client = self.FakeClient()

        user_id = self.example_user('hamlet').id
        data = {'user_id': user_id,
                'id': 'test_missed',
                'email_address': 'foo@bar.baz'}
        fake_client.queue.append(('signups', data))

        fake_response = MagicMock()
        fake_response.status_code = 400
        fake_response.text = ujson.dumps({'title': 'Member Exists'})
        with simulated_queue_client(lambda: fake_client):
            worker = queue_processors.SignupWorker()
            worker.setup()
            with patch('zerver.worker.queue_processors.requests.post',
                       return_value=fake_response), \
                    self.settings(MAILCHIMP_API_KEY='one-two',
                                  PRODUCTION=True,
                                  ZULIP_FRIENDS_LIST_ID='id'):
                with patch('logging.warning') as logging_warning_mock:
                    worker.start()
                    logging_warning_mock.assert_called_once_with(
                        "Attempted to sign up already existing email to list: foo@bar.baz")

    def test_signups_bad_request(self) -> None:
        fake_client = self.FakeClient()

        user_id = self.example_user('hamlet').id
        data = {'user_id': user_id, 'id': 'test_missed'}
        fake_client.queue.append(('signups', data))

        fake_response = MagicMock()
        fake_response.status_code = 444  # Any non-400 bad request code.
        fake_response.text = ujson.dumps({'title': 'Member Exists'})
        with simulated_queue_client(lambda: fake_client):
            worker = queue_processors.SignupWorker()
            worker.setup()
            with patch('zerver.worker.queue_processors.requests.post',
                       return_value=fake_response), \
                    self.settings(MAILCHIMP_API_KEY='one-two',
                                  PRODUCTION=True,
                                  ZULIP_FRIENDS_LIST_ID='id'):
                worker.start()
                fake_response.raise_for_status.assert_called_once()

    def test_invites_worker(self) -> None:
        fake_client = self.FakeClient()
        invitor = self.example_user('iago')
        prereg_alice = PreregistrationUser.objects.create(
            email=self.nonreg_email('alice'), referred_by=invitor, realm=invitor.realm)
        PreregistrationUser.objects.create(
            email=self.nonreg_email('bob'), referred_by=invitor, realm=invitor.realm)
        data = [
            dict(prereg_id=prereg_alice.id, referrer_id=invitor.id, email_body=None),
            # Nonexistent prereg_id, as if the invitation was deleted
            dict(prereg_id=-1, referrer_id=invitor.id, email_body=None),
            # Form with `email` is from versions up to Zulip 1.7.1
            dict(email=self.nonreg_email('bob'), referrer_id=invitor.id, email_body=None),
        ]
        for element in data:
            fake_client.queue.append(('invites', element))

        with simulated_queue_client(lambda: fake_client):
            worker = queue_processors.ConfirmationEmailWorker()
            worker.setup()
            with patch('zerver.worker.queue_processors.do_send_confirmation_email'), \
                    patch('zerver.worker.queue_processors.create_confirmation_link'), \
                    patch('zerver.worker.queue_processors.send_future_email') \
                    as send_mock, \
                    patch('logging.info'):
                worker.start()
                self.assertEqual(send_mock.call_count, 2)

    def test_UserActivityWorker(self) -> None:
        fake_client = self.FakeClient()

        user = self.example_user('hamlet')
        UserActivity.objects.filter(
            user_profile = user.id,
            client = get_client('ios')
        ).delete()

        data = dict(
            user_profile_id = user.id,
            client = 'ios',
            time = time.time(),
            query = 'send_message'
        )
        fake_client.queue.append(('user_activity', data))

        with simulated_queue_client(lambda: fake_client):
            worker = queue_processors.UserActivityWorker()
            worker.setup()
            worker.start()
            activity_records = UserActivity.objects.filter(
                user_profile = user.id,
                client = get_client('ios')
            )
            self.assertTrue(len(activity_records), 1)
            self.assertTrue(activity_records[0].count, 1)

    def test_error_handling(self) -> None:
        processed = []

        @queue_processors.assign_queue('unreliable_worker')
        class UnreliableWorker(queue_processors.QueueProcessingWorker):
            def consume(self, data: Mapping[str, Any]) -> None:
                if data["type"] == 'unexpected behaviour':
                    raise Exception('Worker task not performing as expected!')
                processed.append(data["type"])

        fake_client = self.FakeClient()
        for msg in ['good', 'fine', 'unexpected behaviour', 'back to normal']:
            fake_client.queue.append(('unreliable_worker', {'type': msg}))

        fn = os.path.join(settings.QUEUE_ERROR_DIR, 'unreliable_worker.errors')
        try:
            os.remove(fn)
        except OSError:  # nocoverage # error handling for the directory not existing
            pass

        with simulated_queue_client(lambda: fake_client):
            worker = UnreliableWorker()
            worker.setup()
            with patch('logging.exception') as logging_exception_mock:
                worker.start()
                logging_exception_mock.assert_called_once_with(
                    "Problem handling data on queue unreliable_worker")

        self.assertEqual(processed, ['good', 'fine', 'back to normal'])
        with open(fn, 'r') as f:
            line = f.readline().strip()
        event = ujson.loads(line.split('\t')[1])
        self.assertEqual(event["type"], 'unexpected behaviour')

    def test_worker_noname(self) -> None:
        class TestWorker(queue_processors.QueueProcessingWorker):
            def __init__(self) -> None:
                super().__init__()

            def consume(self, data: Mapping[str, Any]) -> None:
                pass  # nocoverage # this is intentionally not called
        with self.assertRaises(queue_processors.WorkerDeclarationException):
            TestWorker()

    def test_worker_noconsume(self) -> None:
        @queue_processors.assign_queue('test_worker')
        class TestWorker(queue_processors.QueueProcessingWorker):
            def __init__(self) -> None:
                super().__init__()

        with self.assertRaises(queue_processors.WorkerDeclarationException):
            worker = TestWorker()
            worker.consume({})

    def test_get_active_worker_queues(self) -> None:
        worker_queue_count = (len(QueueProcessingWorker.__subclasses__()) +
                              len(EmailSendingWorker.__subclasses__()) +
                              len(LoopQueueProcessingWorker.__subclasses__()) - 1)
        self.assertEqual(worker_queue_count, len(get_active_worker_queues()))
        self.assertEqual(1, len(get_active_worker_queues(queue_type='test')))