text: from typing import Any, Mapping, Optional
  
  from django.http import HttpRequest, HttpResponse
  
  from zerver.decorator import authenticated_rest_api_view
  from zerver.lib.request import REQ, has_request_variables
  from zerver.lib.response import json_success
  from zerver.lib.validator import check_dict
  from zerver.lib.webhooks.common import check_send_webhook_message
  from zerver.lib.webhooks.git import TOPIC_WITH_BRANCH_TEMPLATE, \
      get_push_commits_event_message
  from zerver.models import UserProfile
  
  
  @authenticated_rest_api_view(webhook_client_name="Bitbucket")
  @has_request_variables
  def api_bitbucket_webhook(request: HttpRequest, user_profile: UserProfile,
                            payload: Mapping[str, Any]=REQ(validator=check_dict([])),
                            branches: Optional[str]=REQ(default=None)) -> HttpResponse:
      repository = payload['repository']
  
      commits = [
          {
              'name': commit.get('author') or payload.get('user'),
              'sha': commit.get('raw_node'),
              'message': commit.get('message'),
              'url': '{}{}commits/{}'.format(
                  payload.get('canon_url'),
                  repository.get('absolute_url'),
                  commit.get('raw_node'))
          }
          for commit in payload['commits']
      ]
  
      if len(commits) == 0:
          # Bitbucket doesn't give us enough information to really give
          # a useful message :/
          subject = repository['name']
          content = ("%s [force pushed](%s)."
                     % (payload.get('user', 'Someone'),
                        payload['canon_url'] + repository['absolute_url']))
      else:
          branch = payload['commits'][-1]['branch']
          if branches is not None and branches.find(branch) == -1:
              return json_success()
  
          committer = payload.get('user')
          content = get_push_commits_event_message(
              committer if committer is not None else 'Someone',
              None, branch, commits)
          subject = TOPIC_WITH_BRANCH_TEMPLATE.format(repo=repository['name'], branch=branch)
  
      check_send_webhook_message(request, user_profile, subject, content,
                                 unquote_url_parameters=True)
      return json_success()
  