text: """
  spec:
  https://docs.mattermost.com/administration/bulk-export.html
  """
  import os
  import logging
  import subprocess
  import ujson
  import re
  import shutil
  
  from typing import Any, Callable, Dict, List, Set
  
  from django.conf import settings
  from django.utils.timezone import now as timezone_now
  from django.forms.models import model_to_dict
  
  from zerver.models import Recipient, RealmEmoji, Reaction, UserProfile
  from zerver.lib.utils import (
      process_list_in_batches,
  )
  from zerver.lib.emoji import name_to_codepoint
  from zerver.data_import.import_util import ZerverFieldsT, build_zerver_realm, \
      build_stream, build_realm, build_message, create_converted_data_files, \
      make_subscriber_map, build_recipients, build_user_profile, \
      build_stream_subscriptions, build_huddle_subscriptions, \
      build_personal_subscriptions, SubscriberHandler, \
      build_realm_emoji, make_user_messages, build_huddle
  
  from zerver.data_import.mattermost_user import UserHandler
  from zerver.data_import.sequencer import NEXT_ID, IdMapper
  
  def make_realm(realm_id: int, team: Dict[str, Any]) -> ZerverFieldsT:
      # set correct realm details
      NOW = float(timezone_now().timestamp())
      domain_name = settings.EXTERNAL_HOST
      realm_subdomain = team["name"]
  
      zerver_realm = build_zerver_realm(realm_id, realm_subdomain, NOW, 'Mattermost')
      realm = build_realm(zerver_realm, realm_id, domain_name)
  
      # We may override these later.
      realm['zerver_defaultstream'] = []
  
      return realm
  
  def process_user(user_dict: Dict[str, Any], realm_id: int, team_name: str,
                   user_id_mapper: IdMapper) -> ZerverFieldsT:
      def is_team_admin(user_dict: Dict[str, Any]) -> bool:
          if user_dict["teams"] is None:
              return False
          for team in user_dict["teams"]:
              if team["name"] == team_name and "team_admin" in team["roles"]:
                  return True
          return False
  
      def get_full_name(user_dict: Dict[str, Any]) -> str:
          full_name = "{} {}".format(user_dict["first_name"], user_dict["last_name"])
          if full_name.strip():
              return full_name
          return user_dict['username']
  
      avatar_source = 'G'
      full_name = get_full_name(user_dict)
      id = user_id_mapper.get(user_dict['username'])
      delivery_email = user_dict['email']
      email = user_dict['email']
      short_name = user_dict['username']
      date_joined = int(timezone_now().timestamp())
      timezone = 'UTC'
  
      role = UserProfile.ROLE_MEMBER
      if is_team_admin(user_dict):
          role = UserProfile.ROLE_REALM_ADMINISTRATOR
  
      if user_dict["is_mirror_dummy"]:
          is_active = False
          is_mirror_dummy = True
      else:
          is_active = True
          is_mirror_dummy = False
  
      return build_user_profile(
          avatar_source=avatar_source,
          date_joined=date_joined,
          delivery_email=delivery_email,
          email=email,
          full_name=full_name,
          id=id,
          is_active=is_active,
          role=role,
          is_mirror_dummy=is_mirror_dummy,
          realm_id=realm_id,
          short_name=short_name,
          timezone=timezone,
      )
  
  def convert_user_data(user_handler: UserHandler,
                        user_id_mapper: IdMapper,
                        user_data_map: Dict[str, Dict[str, Any]],
                        realm_id: int,
                        team_name: str) -> None:
  
      user_data_list = []
      for username in user_data_map:
          user = user_data_map[username]
          if check_user_in_team(user, team_name) or user["is_mirror_dummy"]:
              user_data_list.append(user)
  
      for raw_item in user_data_list:
          user = process_user(raw_item, realm_id, team_name, user_id_mapper)
          user_handler.add_user(user)
  
  def convert_channel_data(channel_data: List[ZerverFieldsT],
                           user_data_map: Dict[str, Dict[str, Any]],
                           subscriber_handler: SubscriberHandler,
                           stream_id_mapper: IdMapper,
                           user_id_mapper: IdMapper,
                           realm_id: int,
                           team_name: str) -> List[ZerverFieldsT]:
      channel_data_list = [
          d
          for d in channel_data
          if d['team'] == team_name
      ]
  
      channel_members_map = {}  # type: Dict[str, List[str]]
      channel_admins_map = {}  # type: Dict[str, List[str]]
  
      def initialize_stream_membership_dicts() -> None:
          for channel in channel_data:
              channel_name = channel["name"]
              channel_members_map[channel_name] = []
              channel_admins_map[channel_name] = []
  
          for username in user_data_map:
              user_dict = user_data_map[username]
              teams = user_dict["teams"]
              if user_dict["teams"] is None:
                  continue
  
              for team in teams:
                  if team["name"] != team_name:
                      continue
                  for channel in team["channels"]:
                      channel_roles = channel["roles"]
                      channel_name = channel["name"]
                      if "channel_admin" in channel_roles:
                          channel_admins_map[channel_name].append(username)
                      elif "channel_user" in channel_roles:
                          channel_members_map[channel_name].append(username)
  
      def get_invite_only_value_from_channel_type(channel_type: str) -> bool:
          # Channel can have two types in Mattermost
          # "O" for a public channel.
          # "P" for a private channel.
          if channel_type == 'O':
              return False
          elif channel_type == 'P':
              return True
          else:  # nocoverage
              raise Exception('unexpected value')
  
      streams = []
      initialize_stream_membership_dicts()
  
      for channel_dict in channel_data_list:
          now = int(timezone_now().timestamp())
          stream_id = stream_id_mapper.get(channel_dict['name'])
          stream_name = channel_dict["name"]
          invite_only = get_invite_only_value_from_channel_type(channel_dict['type'])
  
          stream = build_stream(
              date_created=now,
              realm_id=realm_id,
              name=channel_dict['display_name'],
              # Purpose describes how the channel should be used. It is similar to
              # stream description and is shown in channel list to help others decide
              # whether to join.
              # Header text always appears right next to channel name in channel header.
              # Can be used for advertising the purpose of stream, making announcements as
              # well as including frequently used links. So probably not a bad idea to use
              # this as description if the channel purpose is empty.
              description=channel_dict["purpose"] or channel_dict['header'],
              stream_id=stream_id,
              # Mattermost export don't include data of archived(~ deactivated) channels.
              deactivated=False,
              invite_only=invite_only,
          )
  
          channel_users = set()
          for username in channel_admins_map[stream_name]:
              channel_users.add(user_id_mapper.get(username))
  
          for username in channel_members_map[stream_name]:
              channel_users.add(user_id_mapper.get(username))
  
          subscriber_handler.set_info(
              users=channel_users,
              stream_id=stream_id,
          )
          streams.append(stream)
      return streams
  
  def generate_huddle_name(huddle_members: List[str]) -> str:
      # Simple hash function to generate a unique hash key for the
      # members of a huddle.  Needs to be consistent only within the
      # lifetime of export tool run, as it doesn't appear in the output.
      import hashlib
      return hashlib.md5(''.join(sorted(huddle_members)).encode('utf-8')).hexdigest()
  
  def convert_huddle_data(huddle_data: List[ZerverFieldsT],
                          user_data_map: Dict[str, Dict[str, Any]],
                          subscriber_handler: SubscriberHandler,
                          huddle_id_mapper: IdMapper,
                          user_id_mapper: IdMapper,
                          realm_id: int,
                          team_name: str) -> List[ZerverFieldsT]:
  
      zerver_huddle = []
      for huddle in huddle_data:
          if len(huddle["members"]) > 2:
              huddle_name = generate_huddle_name(huddle["members"])
              huddle_id = huddle_id_mapper.get(huddle_name)
              huddle_dict = build_huddle(huddle_id)
              huddle_user_ids = set()
              for username in huddle["members"]:
                  huddle_user_ids.add(user_id_mapper.get(username))
              subscriber_handler.set_info(
                  users=huddle_user_ids,
                  huddle_id=huddle_id,
              )
              zerver_huddle.append(huddle_dict)
      return zerver_huddle
  
  def build_reactions(realm_id: int, total_reactions: List[ZerverFieldsT], reactions: List[ZerverFieldsT],
                      message_id: int,
                      user_id_mapper: IdMapper, zerver_realmemoji: List[ZerverFieldsT]) -> None:
      realmemoji = {}
      for realm_emoji in zerver_realmemoji:
          realmemoji[realm_emoji['name']] = realm_emoji['id']
  
      # For the unicode emoji codes, we use equivalent of
      # function 'emoji_name_to_emoji_code' in 'zerver/lib/emoji' here
      for mattermost_reaction in reactions:
          emoji_name = mattermost_reaction['emoji_name']
          username = mattermost_reaction["user"]
          # Check in unicode emoji
          if emoji_name in name_to_codepoint:
              emoji_code = name_to_codepoint[emoji_name]
              reaction_type = Reaction.UNICODE_EMOJI
          # Check in realm emoji
          elif emoji_name in realmemoji:
              emoji_code = realmemoji[emoji_name]
              reaction_type = Reaction.REALM_EMOJI
          else:  # nocoverage
              continue
  
          if not user_id_mapper.has(username):
              continue
  
          reaction_id = NEXT_ID('reaction')
          reaction = Reaction(
              id=reaction_id,
              emoji_code=emoji_code,
              emoji_name=emoji_name,
              reaction_type=reaction_type)
  
          reaction_dict = model_to_dict(reaction, exclude=['message', 'user_profile'])
          reaction_dict['message'] = message_id
          reaction_dict['user_profile'] = user_id_mapper.get(username)
          total_reactions.append(reaction_dict)
  
  def get_mentioned_user_ids(raw_message: Dict[str, Any], user_id_mapper: IdMapper) -> Set[int]:
      user_ids = set()
      content = raw_message["content"]
  
      # usernames can be of the form user.name, user_name, username., username_, user.name_ etc
      matches = re.findall("(?<=^|(?<=[^a-zA-Z0-9-_.]))@(([A-Za-z0-9]+[_.]?)+)", content)
  
      for match in matches:
          possible_username = match[0]
          if user_id_mapper.has(possible_username):
              user_ids.add(user_id_mapper.get(possible_username))
      return user_ids
  
  def process_raw_message_batch(realm_id: int,
                                raw_messages: List[Dict[str, Any]],
                                subscriber_map: Dict[int, Set[int]],
                                user_id_mapper: IdMapper,
                                user_handler: UserHandler,
                                get_recipient_id_from_receiver_name: Callable[[str, int], int],
                                is_pm_data: bool,
                                output_dir: str,
                                zerver_realmemoji: List[Dict[str, Any]],
                                total_reactions: List[Dict[str, Any]],
                                ) -> None:
  
      def fix_mentions(content: str, mention_user_ids: Set[int]) -> str:
          for user_id in mention_user_ids:
              user = user_handler.get_user(user_id=user_id)
              mattermost_mention = '@{short_name}'.format(**user)
              zulip_mention = '@**{full_name}**'.format(**user)
              content = content.replace(mattermost_mention, zulip_mention)
  
          content = content.replace('@channel', '@**all**')
          content = content.replace('@all', '@**all**')
          # We don't have an equivalent for Mattermost's @here mention which mentions all users
          # online in the channel.
          content = content.replace('@here', '@**all**')
          return content
  
      mention_map = dict()  # type: Dict[int, Set[int]]
      zerver_message = []
  
      import html2text
      h = html2text.HTML2Text()
  
      pm_members = {}
  
      for raw_message in raw_messages:
          message_id = NEXT_ID('message')
          mention_user_ids = get_mentioned_user_ids(raw_message, user_id_mapper)
          mention_map[message_id] = mention_user_ids
  
          content = fix_mentions(
              content=raw_message['content'],
              mention_user_ids=mention_user_ids,
          )
          content = h.handle(content)
  
          if len(content) > 10000:  # nocoverage
              logging.info('skipping too-long message of length %s' % (len(content),))
              continue
  
          date_sent = raw_message['date_sent']
          sender_user_id = raw_message['sender_id']
          if "channel_name" in raw_message:
              recipient_id = get_recipient_id_from_receiver_name(raw_message["channel_name"], Recipient.STREAM)
          elif "huddle_name" in raw_message:
              recipient_id = get_recipient_id_from_receiver_name(raw_message["huddle_name"], Recipient.HUDDLE)
          elif "pm_members" in raw_message:
              members = raw_message["pm_members"]
              member_ids = {user_id_mapper.get(member) for member in members}
              pm_members[message_id] = member_ids
              if sender_user_id == user_id_mapper.get(members[0]):
                  recipient_id = get_recipient_id_from_receiver_name(members[1], Recipient.PERSONAL)
              else:
                  recipient_id = get_recipient_id_from_receiver_name(members[0], Recipient.PERSONAL)
          else:
              raise AssertionError("raw_message without channel_name, huddle_name or pm_members key")
  
          rendered_content = None
  
          topic_name = 'imported from mattermost'
  
          message = build_message(
              content=content,
              message_id=message_id,
              date_sent=date_sent,
              recipient_id=recipient_id,
              rendered_content=rendered_content,
              topic_name=topic_name,
              user_id=sender_user_id,
              has_attachment=False,
          )
          zerver_message.append(message)
          build_reactions(realm_id, total_reactions, raw_message["reactions"], message_id,
                          user_id_mapper, zerver_realmemoji)
  
      zerver_usermessage = make_user_messages(
          zerver_message=zerver_message,
          subscriber_map=subscriber_map,
          is_pm_data=is_pm_data,
          mention_map=mention_map,
      )
  
      message_json = dict(
          zerver_message=zerver_message,
          zerver_usermessage=zerver_usermessage,
      )
  
      dump_file_id = NEXT_ID('dump_file_id' + str(realm_id))
      message_file = "/messages-%06d.json" % (dump_file_id,)
      create_converted_data_files(message_json, output_dir, message_file)
  
  def process_posts(num_teams: int,
                    team_name: str,
                    realm_id: int,
                    post_data: List[Dict[str, Any]],
                    get_recipient_id_from_receiver_name: Callable[[str, int], int],
                    subscriber_map: Dict[int, Set[int]],
                    output_dir: str,
                    is_pm_data: bool,
                    masking_content: bool,
                    user_id_mapper: IdMapper,
                    user_handler: UserHandler,
                    username_to_user: Dict[str, Dict[str, Any]],
                    zerver_realmemoji: List[Dict[str, Any]],
                    total_reactions: List[Dict[str, Any]]) -> None:
  
      post_data_list = []
      for post in post_data:
          if "team" not in post:
              # Mattermost doesn't specify a team for private messages
              # in its export format.  This line of code requires that
              # we only be importing data from a single team (checked
              # elsewhere) -- we just assume it's the target team.
              post_team = team_name
          else:
              post_team = post["team"]
          if post_team == team_name:
              post_data_list.append(post)
  
      def message_to_dict(post_dict: Dict[str, Any]) -> Dict[str, Any]:
          sender_username = post_dict["user"]
          sender_id = user_id_mapper.get(sender_username)
          content = post_dict['message']
  
          if masking_content:
              content = re.sub('[a-z]', 'x', content)
              content = re.sub('[A-Z]', 'X', content)
  
          if "reactions" in post_dict:
              reactions = post_dict["reactions"] or []
          else:
              reactions = []
  
          message_dict = dict(
              sender_id=sender_id,
              content=content,
              date_sent=int(post_dict['create_at'] / 1000),
              reactions=reactions
          )
          if "channel" in post_dict:
              message_dict["channel_name"] = post_dict["channel"]
          elif "channel_members" in post_dict:
              # This case is for handling posts from PMs and huddles, not channels.
              # PMs and huddles are known as direct_channels in Slack and hence
              # the name channel_members.
              channel_members = post_dict["channel_members"]
              if len(channel_members) > 2:
                  message_dict["huddle_name"] = generate_huddle_name(channel_members)
              elif len(channel_members) == 2:
                  message_dict["pm_members"] = channel_members
          else:
              raise AssertionError("Post without channel or channel_members key.")
          return message_dict
  
      raw_messages = []
      for post_dict in post_data_list:
          raw_messages.append(message_to_dict(post_dict))
          message_replies = post_dict["replies"]
          # Replies to a message in Mattermost are stored in the main message object.
          # For now, we just append the replies immediately after the original message.
          if message_replies is not None:
              for reply in message_replies:
                  if 'channel' in post_dict:
                      reply["channel"] = post_dict["channel"]
                  else:  # nocoverage
                      reply["channel_members"] = post_dict["channel_members"]
                  raw_messages.append(message_to_dict(reply))
  
      def process_batch(lst: List[Dict[str, Any]]) -> None:
          process_raw_message_batch(
              realm_id=realm_id,
              raw_messages=lst,
              subscriber_map=subscriber_map,
              user_id_mapper=user_id_mapper,
              user_handler=user_handler,
              get_recipient_id_from_receiver_name=get_recipient_id_from_receiver_name,
              is_pm_data=is_pm_data,
              output_dir=output_dir,
              zerver_realmemoji=zerver_realmemoji,
              total_reactions=total_reactions,
          )
  
      chunk_size = 1000
  
      process_list_in_batches(
          lst=raw_messages,
          chunk_size=chunk_size,
          process_batch=process_batch,
      )
  
  def write_message_data(num_teams: int,
                         team_name: str,
                         realm_id: int,
                         post_data: Dict[str, List[Dict[str, Any]]],
                         zerver_recipient: List[ZerverFieldsT],
                         subscriber_map: Dict[int, Set[int]],
                         output_dir: str,
                         masking_content: bool,
                         stream_id_mapper: IdMapper,
                         huddle_id_mapper: IdMapper,
                         user_id_mapper: IdMapper,
                         user_handler: UserHandler,
                         username_to_user: Dict[str, Dict[str, Any]],
                         zerver_realmemoji: List[Dict[str, Any]],
                         total_reactions: List[Dict[str, Any]]) -> None:
      stream_id_to_recipient_id = {}
      huddle_id_to_recipient_id = {}
      user_id_to_recipient_id = {}
  
      for d in zerver_recipient:
          if d['type'] == Recipient.STREAM:
              stream_id_to_recipient_id[d['type_id']] = d['id']
          elif d['type'] == Recipient.HUDDLE:
              huddle_id_to_recipient_id[d['type_id']] = d['id']
          if d['type'] == Recipient.PERSONAL:
              user_id_to_recipient_id[d['type_id']] = d['id']
  
      def get_recipient_id_from_receiver_name(receiver_name: str, recipient_type: int) -> int:
          if recipient_type == Recipient.STREAM:
              receiver_id = stream_id_mapper.get(receiver_name)
              recipient_id = stream_id_to_recipient_id[receiver_id]
          elif recipient_type == Recipient.HUDDLE:
              receiver_id = huddle_id_mapper.get(receiver_name)
              recipient_id = huddle_id_to_recipient_id[receiver_id]
          elif recipient_type == Recipient.PERSONAL:
              receiver_id = user_id_mapper.get(receiver_name)
              recipient_id = user_id_to_recipient_id[receiver_id]
          else:
              raise AssertionError("Invalid recipient_type")
          return recipient_id
  
      if num_teams == 1:
          post_types = ["channel_post", "direct_post"]
      else:
          post_types = ["channel_post"]
          logging.warning("Skipping importing huddles and PMs since there are multiple teams in the export")
  
      for post_type in post_types:
          process_posts(
              num_teams=num_teams,
              team_name=team_name,
              realm_id=realm_id,
              post_data=post_data[post_type],
              get_recipient_id_from_receiver_name=get_recipient_id_from_receiver_name,
              subscriber_map=subscriber_map,
              output_dir=output_dir,
              is_pm_data=post_type == "direct_post",
              masking_content=masking_content,
              user_id_mapper=user_id_mapper,
              user_handler=user_handler,
              username_to_user=username_to_user,
              zerver_realmemoji=zerver_realmemoji,
              total_reactions=total_reactions,
          )
  
  def write_emoticon_data(realm_id: int,
                          custom_emoji_data: List[Dict[str, Any]],
                          data_dir: str,
                          output_dir: str) -> List[ZerverFieldsT]:
      '''
      This function does most of the work for processing emoticons, the bulk
      of which is copying files.  We also write a json file with metadata.
      Finally, we return a list of RealmEmoji dicts to our caller.
  
      In our data_dir we have a pretty simple setup:
  
          The exported JSON file will have emoji rows if it contains any custom emoji
              {
                  "type": "emoji",
                  "emoji": {"name": "peerdium", "image": "exported_emoji/h15ni7kf1bnj7jeua4qhmctsdo/image"}
              }
              {
                  "type": "emoji",
                  "emoji": {"name": "tick", "image": "exported_emoji/7u7x8ytgp78q8jir81o9ejwwnr/image"}
              }
  
          exported_emoji/ - contains a bunch of image files:
              exported_emoji/7u7x8ytgp78q8jir81o9ejwwnr/image
              exported_emoji/h15ni7kf1bnj7jeua4qhmctsdo/image
  
      We move all the relevant files to Zulip's more nested
      directory structure.
      '''
  
      logging.info('Starting to process emoticons')
  
      flat_data = [
          dict(
              path=d['image'],
              name=d['name'],
          )
          for d in custom_emoji_data
      ]
  
      emoji_folder = os.path.join(output_dir, 'emoji')
      os.makedirs(emoji_folder, exist_ok=True)
  
      def process(data: ZerverFieldsT) -> ZerverFieldsT:
          source_sub_path = data['path']
          source_path = os.path.join(data_dir, source_sub_path)
  
          target_fn = data["name"]
          target_sub_path = RealmEmoji.PATH_ID_TEMPLATE.format(
              realm_id=realm_id,
              emoji_file_name=target_fn,
          )
          target_path = os.path.join(emoji_folder, target_sub_path)
  
          os.makedirs(os.path.dirname(target_path), exist_ok=True)
  
          source_path = os.path.abspath(source_path)
          target_path = os.path.abspath(target_path)
  
          shutil.copyfile(source_path, target_path)
  
          return dict(
              path=target_path,
              s3_path=target_path,
              file_name=target_fn,
              realm_id=realm_id,
              name=data['name'],
          )
  
      emoji_records = list(map(process, flat_data))
      create_converted_data_files(emoji_records, output_dir, '/emoji/records.json')
  
      realmemoji = [
          build_realm_emoji(
              realm_id=realm_id,
              name=rec['name'],
              id=NEXT_ID('realmemoji'),
              file_name=rec['file_name'],
          )
          for rec in emoji_records
      ]
      logging.info('Done processing emoticons')
  
      return realmemoji
  
  def create_username_to_user_mapping(user_data_list: List[Dict[str, Any]]) -> Dict[str, Dict[str, Any]]:
      username_to_user = {}
      for user in user_data_list:
          username_to_user[user["username"]] = user
      return username_to_user
  
  def check_user_in_team(user: Dict[str, Any], team_name: str) -> bool:
      if user["teams"] is None:
          # This is null for users not on any team
          return False
      for team in user["teams"]:
          if team["name"] == team_name:
              return True
      return False
  
  def label_mirror_dummy_users(num_teams: int, team_name: str, mattermost_data: Dict[str, Any],
                               username_to_user: Dict[str, Dict[str, Any]]) -> None:
      # This function might looks like a great place to label admin users. But
      # that won't be fully correct since we are iterating only though posts and
      # it covers only users that has sent atleast one message.
      for post in mattermost_data["post"]["channel_post"]:
          post_team = post["team"]
          if post_team == team_name:
              user = username_to_user[post["user"]]
              if not check_user_in_team(user, team_name):
                  user["is_mirror_dummy"] = True
  
      if num_teams == 1:
          for post in mattermost_data["post"]["direct_post"]:
              assert("team" not in post)
              user = username_to_user[post["user"]]
              if not check_user_in_team(user, team_name):
                  user["is_mirror_dummy"] = True
  
  def reset_mirror_dummy_users(username_to_user: Dict[str, Dict[str, Any]]) -> None:
      for username in username_to_user:
          user = username_to_user[username]
          user["is_mirror_dummy"] = False
  
  def mattermost_data_file_to_dict(mattermost_data_file: str) -> Dict[str, Any]:
      mattermost_data = {}  # type: Dict[str, Any]
      mattermost_data["version"] = []
      mattermost_data["team"] = []
      mattermost_data["channel"] = []
      mattermost_data["user"] = []
      mattermost_data["post"] = {"channel_post": [], "direct_post": []}
      mattermost_data["emoji"] = []
      mattermost_data["direct_channel"] = []
  
      with open(mattermost_data_file, "r") as fp:
          for line in fp:
              row = ujson.loads(line.rstrip("\n"))
              data_type = row["type"]
              if data_type == "post":
                  mattermost_data["post"]["channel_post"].append(row["post"])
              elif data_type == "direct_post":
                  mattermost_data["post"]["direct_post"].append(row["direct_post"])
              else:
                  mattermost_data[data_type].append(row[data_type])
      return mattermost_data
  
  def do_convert_data(mattermost_data_dir: str, output_dir: str, masking_content: bool) -> None:
      username_to_user = {}  # type: Dict[str, Dict[str, Any]]
  
      os.makedirs(output_dir, exist_ok=True)
      if os.listdir(output_dir):  # nocoverage
          raise Exception("Output directory should be empty!")
  
      mattermost_data_file = os.path.join(mattermost_data_dir, "export.json")
      mattermost_data = mattermost_data_file_to_dict(mattermost_data_file)
  
      username_to_user = create_username_to_user_mapping(mattermost_data["user"])
  
      for team in mattermost_data["team"]:
          realm_id = NEXT_ID("realm_id")
          team_name = team["name"]
  
          user_handler = UserHandler()
          subscriber_handler = SubscriberHandler()
          user_id_mapper = IdMapper()
          stream_id_mapper = IdMapper()
          huddle_id_mapper = IdMapper()
  
          print("Generating data for", team_name)
          realm = make_realm(realm_id, team)
          realm_output_dir = os.path.join(output_dir, team_name)
  
          reset_mirror_dummy_users(username_to_user)
          label_mirror_dummy_users(len(mattermost_data["team"]), team_name, mattermost_data, username_to_user)
  
          convert_user_data(
              user_handler=user_handler,
              user_id_mapper=user_id_mapper,
              user_data_map=username_to_user,
              realm_id=realm_id,
              team_name=team_name,
          )
  
          zerver_stream = convert_channel_data(
              channel_data=mattermost_data["channel"],
              user_data_map=username_to_user,
              subscriber_handler=subscriber_handler,
              stream_id_mapper=stream_id_mapper,
              user_id_mapper=user_id_mapper,
              realm_id=realm_id,
              team_name=team_name,
          )
          realm['zerver_stream'] = zerver_stream
  
          zerver_huddle = []  # type: List[ZerverFieldsT]
          if len(mattermost_data["team"]) == 1:
              zerver_huddle = convert_huddle_data(
                  huddle_data=mattermost_data["direct_channel"],
                  user_data_map=username_to_user,
                  subscriber_handler=subscriber_handler,
                  huddle_id_mapper=huddle_id_mapper,
                  user_id_mapper=user_id_mapper,
                  realm_id=realm_id,
                  team_name=team_name,
              )
              realm['zerver_huddle'] = zerver_huddle
  
          all_users = user_handler.get_all_users()
  
          zerver_recipient = build_recipients(
              zerver_userprofile=all_users,
              zerver_stream=zerver_stream,
              zerver_huddle=zerver_huddle,
          )
          realm['zerver_recipient'] = zerver_recipient
  
          stream_subscriptions = build_stream_subscriptions(
              get_users=subscriber_handler.get_users,
              zerver_recipient=zerver_recipient,
              zerver_stream=zerver_stream,
          )
  
          huddle_subscriptions = build_huddle_subscriptions(
              get_users=subscriber_handler.get_users,
              zerver_recipient=zerver_recipient,
              zerver_huddle=zerver_huddle,
          )
  
          personal_subscriptions = build_personal_subscriptions(
              zerver_recipient=zerver_recipient,
          )
  
          # Mattermost currently supports only exporting messages from channels.
          # Personal messages and huddles are not exported.
          zerver_subscription = personal_subscriptions + stream_subscriptions + huddle_subscriptions
          realm['zerver_subscription'] = zerver_subscription
  
          zerver_realmemoji = write_emoticon_data(
              realm_id=realm_id,
              custom_emoji_data=mattermost_data["emoji"],
              data_dir=mattermost_data_dir,
              output_dir=realm_output_dir,
          )
          realm['zerver_realmemoji'] = zerver_realmemoji
  
          subscriber_map = make_subscriber_map(
              zerver_subscription=zerver_subscription,
          )
  
          total_reactions = []  # type: List[Dict[str, Any]]
          write_message_data(
              num_teams=len(mattermost_data["team"]),
              team_name=team_name,
              realm_id=realm_id,
              post_data=mattermost_data["post"],
              zerver_recipient=zerver_recipient,
              subscriber_map=subscriber_map,
              output_dir=realm_output_dir,
              masking_content=masking_content,
              stream_id_mapper=stream_id_mapper,
              huddle_id_mapper=huddle_id_mapper,
              user_id_mapper=user_id_mapper,
              user_handler=user_handler,
              username_to_user=username_to_user,
              zerver_realmemoji=zerver_realmemoji,
              total_reactions=total_reactions,
          )
          realm['zerver_reaction'] = total_reactions
          realm['zerver_userprofile'] = user_handler.get_all_users()
          realm['sort_by_date'] = True
  
          create_converted_data_files(realm, realm_output_dir, '/realm.json')
          # Mattermost currently doesn't support exporting avatars
          create_converted_data_files([], realm_output_dir, '/avatars/records.json')
          # Mattermost currently doesn't support exporting uploads
          create_converted_data_files([], realm_output_dir, '/uploads/records.json')
  
          # Mattermost currently doesn't support exporting attachments
          attachment = {"zerver_attachment": []}  # type: Dict[str, List[Any]]
          create_converted_data_files(attachment, realm_output_dir, '/attachment.json')
  
          logging.info('Start making tarball')
          subprocess.check_call(["tar", "-czf", realm_output_dir + '.tar.gz', realm_output_dir, '-P'])
          logging.info('Done making tarball')
  