import logging
import time
from datetime import timedelta
from typing import Any

from django.conf import settings
from django.core.management.base import BaseCommand
from django.db import transaction
from django.utils.timezone import now as timezone_now

from zerver.lib.actions import build_message_send_dict, do_send_messages
from zerver.lib.logging_util import log_to_file
from zerver.lib.message import SendMessageRequest
from zerver.models import Message, ScheduledMessage, get_user_by_delivery_email

## Setup ##
logger = logging.getLogger(__name__)
log_to_file(logger, settings.DELIVER_SCHEDULED_MESSAGES_LOG_PATH)


class Command(BaseCommand):
    help = """Deliver scheduled messages from the ScheduledMessage table.
Run this command under supervisor.

This management command is run via supervisor.

Usage: ./manage.py deliver_scheduled_messages
"""

    def construct_message(self, scheduled_message: ScheduledMessage) -> SendMessageRequest:
        message = Message()
        original_sender = scheduled_message.sender
        message.content = scheduled_message.content
        message.recipient = scheduled_message.recipient
        message.subject = scheduled_message.subject
        message.date_sent = timezone_now()
        message.sending_client = scheduled_message.sending_client

        delivery_type = scheduled_message.delivery_type
        if delivery_type == ScheduledMessage.SEND_LATER:
            message.sender = original_sender
        elif delivery_type == ScheduledMessage.REMIND:
            message.sender = get_user_by_delivery_email(
                settings.NOTIFICATION_BOT, original_sender.realm
            )

        return build_message_send_dict(
            message=message, stream=scheduled_message.stream, realm=scheduled_message.realm
        )

    def handle(self, *args: Any, **options: Any) -> None:
        try:
            while True:
                with transaction.atomic():
                    messages_to_deliver = ScheduledMessage.objects.filter(
                        scheduled_timestamp__lte=timezone_now(), delivered=False
                    ).select_for_update()
                    for message in messages_to_deliver:
                        do_send_messages([self.construct_message(message)])
                        message.delivered = True
                        message.save(update_fields=["delivered"])

                cur_time = timezone_now()
                time_next_min = (cur_time + timedelta(minutes=1)).replace(second=0, microsecond=0)
                sleep_time = (time_next_min - cur_time).total_seconds()
                time.sleep(sleep_time)
        except KeyboardInterrupt:
            pass