from __future__ import absolute_import
from typing import Any, Callable, Mapping

from django.conf import settings
from django.core.handlers.wsgi import WSGIRequest
from django.core.handlers.base import BaseHandler
from zerver.models import get_user_profile_by_email, \
    get_user_profile_by_id, get_prereg_user_by_email, get_client, \
    UserMessage, Message
from zerver.lib.context_managers import lockfile
from zerver.lib.queue import SimpleQueueClient, queue_json_publish
from zerver.lib.timestamp import timestamp_to_datetime
from zerver.lib.notifications import handle_missedmessage_emails, enqueue_welcome_emails, \
    clear_followup_emails_queue, send_local_email_template_with_delay
from zerver.lib.actions import do_send_confirmation_email, \
    do_update_user_activity, do_update_user_activity_interval, do_update_user_presence, \
    internal_send_message, check_send_message, extract_recipients, \
    handle_push_notification, render_incoming_message, do_update_embedded_data
from zerver.lib.url_preview import preview as url_preview
from zerver.lib.digest import handle_digest_email
from zerver.lib.email_mirror import process_message as mirror_email
from zerver.decorator import JsonableError
from zerver.tornado.socket import req_redis_key
from confirmation.models import Confirmation
from zerver.lib.db import reset_queries
from django.core.mail import EmailMessage
from zerver.lib.redis_utils import get_redis_client
from zerver.context_processors import common_context

import os
import sys
import ujson
from collections import defaultdict
import email
import time
import datetime
import logging
import requests
import simplejson
from six.moves import cStringIO as StringIO

class WorkerDeclarationException(Exception):
    pass

def assign_queue(queue_name, enabled=True):
    # type: (str, bool) -> Callable[[QueueProcessingWorker], QueueProcessingWorker]
    def decorate(clazz):
        # type: (QueueProcessingWorker) -> QueueProcessingWorker
        clazz.queue_name = queue_name
        if enabled:
            register_worker(queue_name, clazz)
        return clazz
    return decorate

worker_classes = {} # type: Dict[str, Any] # Any here should be QueueProcessingWorker type
def register_worker(queue_name, clazz):
    # type: (str, QueueProcessingWorker) -> None
    worker_classes[queue_name] = clazz

def get_worker(queue_name):
    # type: (str) -> QueueProcessingWorker
    return worker_classes[queue_name]()

def get_active_worker_queues():
    # type: () -> List[str]
    return list(worker_classes.keys())

class QueueProcessingWorker(object):
    queue_name = None # type: str

    def __init__(self):
        # type: () -> None
        self.q = None # type: SimpleQueueClient
        if self.queue_name is None:
            raise WorkerDeclarationException("Queue worker declared without queue_name")

    def consume(self, data):
        # type: (Mapping[str, Any]) -> None
        raise WorkerDeclarationException("No consumer defined!")

    def consume_wrapper(self, data):
        # type: (Mapping[str, Any]) -> None
        try:
            self.consume(data)
        except Exception:
            self._log_problem()
            if not os.path.exists(settings.QUEUE_ERROR_DIR):
                os.mkdir(settings.QUEUE_ERROR_DIR)
            fname = '%s.errors' % (self.queue_name,)
            fn = os.path.join(settings.QUEUE_ERROR_DIR, fname)
            line = u'%s\t%s\n' % (time.asctime(), ujson.dumps(data))
            lock_fn = fn + '.lock'
            with lockfile(lock_fn):
                with open(fn, 'ab') as f:
                    f.write(line.encode('utf-8'))
        reset_queries()

    def _log_problem(self):
        # type: () -> None
        logging.exception("Problem handling data on queue %s" % (self.queue_name,))

    def setup(self):
        # type: () -> None
        self.q = SimpleQueueClient()

    def start(self):
        # type: () -> None
        self.q.register_json_consumer(self.queue_name, self.consume_wrapper)
        self.q.start_consuming()

    def stop(self):
        # type: () -> None
        self.q.stop_consuming()

@assign_queue('signups')
class SignupWorker(QueueProcessingWorker):
    def consume(self, data):
        # type: (Mapping[str, Any]) -> None
        # This should clear out any invitation reminder emails
        clear_followup_emails_queue(data['email_address'])
        if settings.MAILCHIMP_API_KEY and settings.PRODUCTION:
            endpoint = "https://%s.api.mailchimp.com/3.0/lists/%s/members" % \
                       (settings.MAILCHIMP_API_KEY.split('-')[1], settings.ZULIP_FRIENDS_LIST_ID)
            params = dict(data)
            params['list_id'] = settings.ZULIP_FRIENDS_LIST_ID
            params['status'] = 'subscribed'
            r = requests.post(endpoint, auth=('apikey', settings.MAILCHIMP_API_KEY), json=params, timeout=10)
            if r.status_code == 400 and ujson.loads(r.text)['title'] == 'Member Exists':
                logging.warning("Attempted to sign up already existing email to list: %s" %
                                (data['email_address'],))
            else:
                r.raise_for_status()

        enqueue_welcome_emails(data['email_address'], data['merge_fields']['NAME'])

@assign_queue('invites')
class ConfirmationEmailWorker(QueueProcessingWorker):
    def consume(self, data):
        # type: (Mapping[str, Any]) -> None
        invitee = get_prereg_user_by_email(data["email"])
        referrer = get_user_profile_by_email(data["referrer_email"])
        do_send_confirmation_email(invitee, referrer)

        # queue invitation reminder for two days from now.
        link = Confirmation.objects.get_link_for_object(invitee, host=referrer.realm.host)
        context = common_context(referrer)
        context.update({
            'activate_url': link,
            'referrer': referrer,
            'verbose_support_offers': settings.VERBOSE_SUPPORT_OFFERS,
            'support_email': settings.ZULIP_ADMINISTRATOR
        })
        send_local_email_template_with_delay(
            [{'email': data["email"], 'name': ""}],
            "zerver/emails/invitation/invitation_reminder_email",
            context,
            datetime.timedelta(days=2),
            tags=["invitation-reminders"],
            sender={'email': settings.ZULIP_ADMINISTRATOR, 'name': 'Zulip'})

@assign_queue('user_activity')
class UserActivityWorker(QueueProcessingWorker):
    def consume(self, event):
        # type: (Mapping[str, Any]) -> None
        user_profile = get_user_profile_by_id(event["user_profile_id"])
        client = get_client(event["client"])
        log_time = timestamp_to_datetime(event["time"])
        query = event["query"]
        do_update_user_activity(user_profile, client, query, log_time)

@assign_queue('user_activity_interval')
class UserActivityIntervalWorker(QueueProcessingWorker):
    def consume(self, event):
        # type: (Mapping[str, Any]) -> None
        user_profile = get_user_profile_by_id(event["user_profile_id"])
        log_time = timestamp_to_datetime(event["time"])
        do_update_user_activity_interval(user_profile, log_time)

@assign_queue('user_presence')
class UserPresenceWorker(QueueProcessingWorker):
    def consume(self, event):
        # type: (Mapping[str, Any]) -> None
        logging.info("Received event: %s" % (event),)
        user_profile = get_user_profile_by_id(event["user_profile_id"])
        client = get_client(event["client"])
        log_time = timestamp_to_datetime(event["time"])
        status = event["status"]
        do_update_user_presence(user_profile, client, log_time, status)

@assign_queue('missedmessage_emails')
class MissedMessageWorker(QueueProcessingWorker):
    def start(self):
        # type: () -> None
        while True:
            missed_events = self.q.drain_queue("missedmessage_emails", json=True)
            by_recipient = defaultdict(list) # type: Dict[int, List[Dict[str, Any]]]

            for event in missed_events:
                logging.info("Received event: %s" % (event,))
                by_recipient[event['user_profile_id']].append(event)

            for user_profile_id, events in by_recipient.items():
                handle_missedmessage_emails(user_profile_id, events)

            reset_queries()
            # Aggregate all messages received every 2 minutes to let someone finish sending a batch
            # of messages
            time.sleep(2 * 60)

@assign_queue('missedmessage_mobile_notifications')
class PushNotificationsWorker(QueueProcessingWorker):
    def consume(self, data):
        # type: (Mapping[str, Any]) -> None
        handle_push_notification(data['user_profile_id'], data)

def make_feedback_client():
    # type: () -> Any # Should be zulip.Client, but not necessarily importable
    sys.path.append(os.path.join(os.path.dirname(__file__), '../../api'))
    import zulip
    return zulip.Client(
        client="ZulipFeedback/0.1",
        email=settings.DEPLOYMENT_ROLE_NAME,
        api_key=settings.DEPLOYMENT_ROLE_KEY,
        verbose=True,
        site=settings.FEEDBACK_TARGET)

# We probably could stop running this queue worker at all if ENABLE_FEEDBACK is False
@assign_queue('feedback_messages')
class FeedbackBot(QueueProcessingWorker):
    def start(self):
        # type: () -> None
        if settings.ENABLE_FEEDBACK and settings.FEEDBACK_EMAIL is None:
            self.staging_client = make_feedback_client()
        QueueProcessingWorker.start(self)

    def consume(self, event):
        # type: (Mapping[str, Any]) -> None
        logging.info("Received feedback from %s" % (event["sender_email"],))
        if not settings.ENABLE_FEEDBACK:
            return
        if settings.FEEDBACK_EMAIL is not None:
            to_email = settings.FEEDBACK_EMAIL
            subject = "Zulip feedback from %s" % (event["sender_email"],)
            content = event["content"]
            from_email = '"%s" <%s>' % (event["sender_full_name"], settings.ZULIP_ADMINISTRATOR)
            headers = {'Reply-To': '"%s" <%s>' % (event["sender_full_name"], event["sender_email"])}
            msg = EmailMessage(subject, content, from_email, [to_email], headers=headers)
            msg.send()
        else:
            # This code has been untested with the new API, and
            # the endpoint it hits also uses a home-grown ticketing
            # system that was from early days of Zulip, pre-open-source.
            self.staging_client.call_endpoint(
                method='POST',
                url='deployments/feedback',
                request=dict(message=simplejson.dumps(event))
            )

@assign_queue('error_reports')
class ErrorReporter(QueueProcessingWorker):
    def start(self):
        # type: () -> None
        if settings.DEPLOYMENT_ROLE_KEY:
            self.staging_client = make_feedback_client()
            self.staging_client._register(
                'forward_error',
                method='POST',
                url='deployments/report_error',
                make_request=(lambda type, report: {'type': type, 'report': simplejson.dumps(report)}),
                )
        QueueProcessingWorker.start(self)

    def consume(self, event):
        # type: (Mapping[str, Any]) -> None
        if settings.DEPLOYMENT_ROLE_KEY:
            self.staging_client.forward_error(event['type'], event['report'])
        elif settings.ZILENCER_ENABLED:
            from zilencer.views import do_report_error
            do_report_error(settings.DEPLOYMENT_ROLE_NAME, event['type'], event['report'])

@assign_queue('slow_queries')
class SlowQueryWorker(QueueProcessingWorker):
    def start(self):
        # type: () -> None
        while True:
            self.process_one_batch()
            # Aggregate all slow query messages in 1-minute chunks to avoid message spam
            time.sleep(1 * 60)

    def process_one_batch(self):
        # type: () -> None
        slow_queries = self.q.drain_queue("slow_queries", json=True)

        if settings.ERROR_BOT is None:
            return

        if len(slow_queries) > 0:
            topic = "%s: slow queries" % (settings.EXTERNAL_HOST,)

            content = ""
            for query in slow_queries:
                content += "    %s\n" % (query,)

            internal_send_message(settings.ERROR_BOT, "stream", "logs", topic, content)

        reset_queries()

@assign_queue("message_sender")
class MessageSenderWorker(QueueProcessingWorker):
    def __init__(self):
        # type: () -> None
        super(MessageSenderWorker, self).__init__()
        self.redis_client = get_redis_client()
        self.handler = BaseHandler()
        self.handler.load_middleware()

    def consume(self, event):
        # type: (Mapping[str, Any]) -> None
        server_meta = event['server_meta']

        environ = {'REQUEST_METHOD': 'SOCKET',
                   'SCRIPT_NAME': '',
                   'PATH_INFO': '/json/messages',
                   'SERVER_NAME': '127.0.0.1',
                   'SERVER_PORT': 9993,
                   'SERVER_PROTOCOL': 'ZULIP_SOCKET/1.0',
                   'wsgi.version': (1, 0),
                   'wsgi.input': StringIO(),
                   'wsgi.errors': sys.stderr,
                   'wsgi.multithread': False,
                   'wsgi.multiprocess': True,
                   'wsgi.run_once': False,
                   'zulip.emulated_method': 'POST'}
        # We're mostly using a WSGIRequest for convenience
        environ.update(server_meta['request_environ'])
        request = WSGIRequest(environ)
        # Note: If we ever support non-POST methods, we'll need to change this.
        request._post = event['request']
        request.csrf_processing_done = True

        user_profile = get_user_profile_by_id(server_meta['user_id'])
        request._cached_user = user_profile

        resp = self.handler.get_response(request)
        server_meta['time_request_finished'] = time.time()
        server_meta['worker_log_data'] = request._log_data

        resp_content = resp.content.decode('utf-8')
        result = {'response': ujson.loads(resp_content), 'req_id': event['req_id'],
                  'server_meta': server_meta}

        redis_key = req_redis_key(event['req_id'])
        self.redis_client.hmset(redis_key, {'status': 'complete',
                                            'response': resp_content})

        queue_json_publish(server_meta['return_queue'], result, lambda e: None)

@assign_queue('digest_emails')
class DigestWorker(QueueProcessingWorker):
    # Who gets a digest is entirely determined by the enqueue_digest_emails
    # management command, not here.
    def consume(self, event):
        # type: (Mapping[str, Any]) -> None
        logging.info("Received digest event: %s" % (event,))
        handle_digest_email(event["user_profile_id"], event["cutoff"])

@assign_queue('email_mirror')
class MirrorWorker(QueueProcessingWorker):
    # who gets a digest is entirely determined by the enqueue_digest_emails
    # management command, not here.
    def consume(self, event):
        # type: (Mapping[str, Any]) -> None
        mirror_email(email.message_from_string(event["message"]),
                     rcpt_to=event["rcpt_to"], pre_checked=True)

@assign_queue('test')
class TestWorker(QueueProcessingWorker):
    # This worker allows you to test the queue worker infrastructure without
    # creating significant side effects.  It can be useful in development or
    # for troubleshooting prod/staging.  It pulls a message off the test queue
    # and appends it to a file in /tmp.
    def consume(self, event):
        # type: (Mapping[str, Any]) -> None
        fn = settings.ZULIP_WORKER_TEST_FILE
        message = ujson.dumps(event)
        logging.info("TestWorker should append this message to %s: %s" % (fn, message))
        with open(fn, 'a') as f:
            f.write(message + '\n')

@assign_queue('embed_links')
class FetchLinksEmbedData(QueueProcessingWorker):
    def consume(self, event):
        # type: (Mapping[str, Any]) -> None
        for url in event['urls']:
            url_preview.get_link_embed_data(url)

        message = Message.objects.get(id=event['message_id'])
        # If the message changed, we will run this task after updating the message
        # in zerver.views.messages.update_message_backend
        if message.content != event['message_content']:
            return
        if message.content is not None:
            ums = UserMessage.objects.filter(
                message=message.id).select_related("user_profile")
            message_users = {um.user_profile for um in ums}
            # If rendering fails, the called code will raise a JsonableError.
            rendered_content = render_incoming_message(
                message,
                content=message.content,
                message_users=message_users)
            do_update_embedded_data(
                message.sender, message, message.content, rendered_content)
