text: # Webhooks for external integrations.
  import re
  from typing import Any, Dict, List
  
  from django.http import HttpRequest, HttpResponse
  
  from zerver.decorator import webhook_view
  from zerver.lib.exceptions import UnsupportedWebhookEventType
  from zerver.lib.request import REQ, has_request_variables
  from zerver.lib.response import json_success
  from zerver.lib.webhooks.common import check_send_webhook_message
  from zerver.models import UserProfile
  
  TOPIC_TEMPLATE = "{service_url}"
  
  
  def send_message_for_event(
      request: HttpRequest, user_profile: UserProfile, event: Dict[str, Any]
  ) -> None:
      event_type = get_event_type(event)
      subject = TOPIC_TEMPLATE.format(service_url=event["check"]["url"])
      body = EVENT_TYPE_BODY_MAPPER[event_type](event)
      check_send_webhook_message(request, user_profile, subject, body, event_type)
  
  
  def get_body_for_up_event(event: Dict[str, Any]) -> str:
      body = "Service is `up`"
      event_downtime = event["downtime"]
      if event_downtime["started_at"]:
          body = f"{body} again"
          string_date = get_time_string_based_on_duration(event_downtime["duration"])
          if string_date:
              body = f"{body} after {string_date}"
      return f"{body}."
  
  
  def get_time_string_based_on_duration(duration: int) -> str:
      days, reminder = divmod(duration, 86400)
      hours, reminder = divmod(reminder, 3600)
      minutes, seconds = divmod(reminder, 60)
  
      string_date = ""
      string_date += add_time_part_to_string_date_if_needed(days, "day")
      string_date += add_time_part_to_string_date_if_needed(hours, "hour")
      string_date += add_time_part_to_string_date_if_needed(minutes, "minute")
      string_date += add_time_part_to_string_date_if_needed(seconds, "second")
      return string_date.rstrip()
  
  
  def add_time_part_to_string_date_if_needed(value: int, text_name: str) -> str:
      if value == 1:
          return f"1 {text_name} "
      if value > 1:
          return f"{value} {text_name}s "
      return ""
  
  
  def get_body_for_down_event(event: Dict[str, Any]) -> str:
      return "Service is `down`. It returned a {} error at {}.".format(
          event["downtime"]["error"],
          event["downtime"]["started_at"].replace("T", " ").replace("Z", " UTC"),
      )
  
  
  EVENT_TYPE_BODY_MAPPER = {
      "up": get_body_for_up_event,
      "down": get_body_for_down_event,
  }
  ALL_EVENT_TYPES = list(EVENT_TYPE_BODY_MAPPER.keys())
  
  
  @webhook_view("Updown", all_event_types=ALL_EVENT_TYPES)
  @has_request_variables
  def api_updown_webhook(
      request: HttpRequest,
      user_profile: UserProfile,
      payload: List[Dict[str, Any]] = REQ(argument_type="body"),
  ) -> HttpResponse:
      for event in payload:
          send_message_for_event(request, user_profile, event)
      return json_success()
  
  
  def get_event_type(event: Dict[str, Any]) -> str:
      event_type_match = re.match("check.(.*)", event["event"])
      if event_type_match:
          event_type = event_type_match.group(1)
          if event_type in EVENT_TYPE_BODY_MAPPER:
              return event_type
      raise UnsupportedWebhookEventType(event["event"])
  