def anno_insert(self, request):
        """
        Exposes an API endpoint to insert an anno for the current user.

        if current user doesn't exist, the user will be created first.
        """
        user = auth_user(self.request_state.headers)

        # checking if same anno exists
        exist_anno = Anno.is_anno_exists(user, request)
        if exist_anno is not None:
            raise endpoints.BadRequestException("Duplicate anno(%s) already exists." % exist_anno.key.id())

        entity = Anno.insert_anno(request, user)

        # find all hashtags
        tags = extract_tags_from_text(entity.anno_text.lower())
        for tag, count in tags.iteritems():
            # Write the cumulative amount per tag
            Tag.add_tag_total(tag, total=count)

        # index this document. strange exception here.
        put_search_document(entity.generate_search_document(), SearchIndexName.ANNO)

        # send push notifications
        ActivityPushNotifications.send_push_notification(first_user=user, anno=entity, action_type=AnnoActionType.CREATED)

        return entity.to_response_message(user)

    def anno_my_stuff(self, request):
        """
        Exposes an API endpoint to return all my anno list.
        """
        user = auth_user(self.request_state.headers)
        anno_list = Anno.query_anno_by_author(user)
        vote_list = Vote.query_vote_by_author(user)
        for vote in vote_list:
            anno = Anno.get_by_id(vote.anno_key.id())
            if anno is not None:
                anno_list.append(anno)
        flag_list = Flag.query_flag_by_author(user)
        for flag in flag_list:
            anno = Anno.get_by_id(flag.anno_key.id())
            if anno is not None:
                anno_list.append(anno)
        followup_list = FollowUp.query_followup_by_author(user)
        for followup in followup_list:
            anno = Anno.get_by_id(followup.anno_key.id())
            if anno is not None:
                anno_list.append(anno)
        anno_set = list(set(anno_list))

        anno_message_list = []
        for anno in anno_set:
            anno_message_list.append(anno.to_response_message())
        return AnnoListMessage(anno_list=anno_message_list)

    def anno_insert(self, request):
        """
        Exposes an API endpoint to insert an anno for the current user.

        if current user doesn't exist, the user will be created first.
        """
        user = auth_user(self.request_state.headers)
        if Anno.is_anno_exists(user, request):
            raise endpoints.BadRequestException("Duplicate anno already exists.")
        entity = Anno.insert_anno(request, user)
        return entity.to_response_message()

 def anno_delete(self, request):
     """
     Exposes an API endpoint to delete an existing anno.
     """
     user = auth_user(self.request_state.headers)
     if request.id is None:
         raise endpoints.BadRequestException('id field is required.')
     anno = Anno.get_by_id(request.id)
     if anno is None:
         raise endpoints.NotFoundException('No anno entity with the id "%s" exists.' % request.id)
     Anno.delete(anno)
     return message_types.VoidMessage()

    def vote_insert(self, request):
        """
        Exposes an API endpoint to insert a vote for the current user.
        """
        user = auth_user(self.request_state.headers)

        anno = Anno.get_by_id(request.anno_id)
        if anno is None:
            raise endpoints.NotFoundException('No anno entity with the id "%s" exists.' % request.id)

        vote = Vote()
        vote.anno_key = anno.key
        vote.creator = user.key
        if request.created is not None:
            vote.created = request.created
        vote.put()

        anno.vote_count += 1
        anno.last_update_time = datetime.datetime.now()
        anno.last_activity = 'vote'
        anno.last_update_type = 'create'
        anno.put()

        # update user anno state
        UserAnnoState.insert(user=user, anno=anno, type=AnnoActionType.UPVOTED)

        # update vote in search document
        put_search_document(anno.generate_search_document(), SearchIndexName.ANNO)

        return vote.to_message()

    def anno_merge(self, request):
        """
        Exposes an API endpoint to merge(update only the specified properties) an anno.
        """
        user = auth_user(self.request_state.headers)

        if request.id is None:
            raise endpoints.BadRequestException('id field is required.')

        anno = Anno.get_by_id(request.id)

        if anno is None:
            raise endpoints.NotFoundException('No anno entity with the id "%s" exists.' % request.id)

        anno.merge_from_message(request, user)
        # set last update time & activity
        anno.last_update_time = datetime.datetime.now()
        anno.last_activity = 'anno'
        anno.put()

        # update search document.
        put_search_document(anno.generate_search_document(), SearchIndexName.ANNO)

        # send notifications
        ActivityPushNotifications.send_push_notification(first_user=user, anno=anno, action_type=AnnoActionType.EDITED)

        # update last_read of UserAnnoState
        from model.userannostate import UserAnnoState
        UserAnnoState.update_last_read(user=user, anno=anno)

        return anno.to_response_message(user)

    def list_favorite_apps(cls, user_key):
        # We are using "query" on key for getting anno data instead of "get" or "get_multi"
        # Getting anno using "query" is more memory efficient than using "get" or "get_multi",
        # we don't know why.
        # Getting anno using "query" also create index for this.

        from model.userannostate import UserAnnoState
        from model.anno import Anno

        userannostate_list = UserAnnoState.list_by_user(user_key, 50)
        anno_key_list = [ userannostate.anno for userannostate in userannostate_list if userannostate.anno is not None ]

        if len(anno_key_list):
            anno_list = Anno.query(ndb.AND(Anno.key.IN(anno_key_list),
                                           Anno.app != None)
                                   )\
                            .fetch(projection=[Anno.app])
            app_key_list = [ anno.app for anno in anno_list ]
            app_key_list = sorted(app_key_list, key=app_key_list.count, reverse=True)
            unique_app_key_list = []
            [ unique_app_key_list.append(app_key) for app_key in app_key_list if app_key not in unique_app_key_list ]
            app_list = ndb.get_multi(unique_app_key_list)
        else:
            app_list = []

        favorite_apps_list = []
        for app in app_list:
            if app:
                app_message = UserFavoriteApp(name=app.name, icon_url=(app.icon_url or ""), version=(app.version or ""))
                favorite_apps_list.append(app_message)

        return favorite_apps_list

    def followup_insert(self, request):
        """
        Exposes and API endpoint to insert a follow up for the current user.
        """
        user = auth_user(self.request_state.headers)

        anno = Anno.get_by_id(request.anno_id)
        if anno is None:
            raise endpoints.NotFoundException('No anno entity with the id "%s" exists.' % request.id)

        followup = FollowUp()
        followup.anno_key = anno.key
        followup.creator = user.key
        followup.comment = request.comment
        if request.created is not None:
            followup.created = request.created
        followup.put()

        anno.followup_count += 1
        anno.last_update_time = datetime.datetime.now()
        anno.last_activity = 'follwup'
        anno.last_update_type = 'create'
        anno.put()
        # update search document
        put_search_document(anno.generate_search_document())
        return followup.to_message()

    def anno_insert(self, request):
        """
        Exposes an API endpoint to insert an anno for the current user.

        if current user doesn't exist, the user will be created first.
        """
        user = auth_user(self.request_state.headers)
        exist_anno = Anno.is_anno_exists(user, request)
        if exist_anno is not None:
            raise endpoints.BadRequestException("Duplicate anno(%s) already exists." % exist_anno.key.id())
        entity = Anno.insert_anno(request, user)

        # index this document. strange exception here.
        put_search_document(entity.generate_search_document())

        return entity.to_response_message()

    def flag_insert(self, request):
        """
        Exposes an API endpoint to insert a flag for the current user.
        """
        user = auth_user(self.request_state.headers)

        anno = Anno.get_by_id(request.anno_id)
        if anno is None:
            raise endpoints.NotFoundException('No anno entity with the id "%s" exists.')

        flag = Flag()
        flag.anno_key = anno.key
        flag.creator = user.key
        if request.created is not None:
            flag.created = request.created
        flag.put()

        anno.flag_count += 1
        anno.last_update_time = datetime.datetime.now()
        anno.last_activity = 'flag'
        anno.last_update_type = 'create'
        anno.put()

        # update user anno state
        UserAnnoState.insert(user=user, anno=anno, type=AnnoActionType.FLAGGED)

        # update flag in search document
        put_search_document(anno.generate_search_document(), SearchIndexName.ANNO)

        return flag.to_message()

    def flag_delete(self, request):
        """
        Exposes an API endpoint to delete an existing flag.
        """
        user = auth_user(self.request_state.headers)
        anno = None
        if request.id is None and request.anno_id is None:
            raise endpoints.BadRequestException('id or anno_id field is required.')
        if request.id is not None:
            flag = Flag.get_by_id(request.id)
            if flag is None:
                raise endpoints.NotFoundException('No flag entity with the id "%s" exists.' % request.id)

            anno = flag.anno_key.get()
            flag.key.delete()
            anno.flag_count -= 1
            anno.put()
        elif request.anno_id is not None:
            anno = Anno.get_by_id(request.anno_id)
            for key in Flag.query(Flag.anno_key == anno.key, Flag.creator == user.key).iter(keys_only=True):
                key.delete()
                anno.flag_count -= 1
                anno.put()
        put_search_document(anno.generate_search_document(), SearchIndexName.ANNO)
        return message_types.VoidMessage()

    def anno_get(self, request):
        """
        Exposes an API endpoint to get an anno detail by the specified id.
        """
        try:
            user = auth_user(self.request_state.headers)
        except Exception:
            user = None

        if request.id is None:
            raise endpoints.BadRequestException('id field is required.')

        anno = Anno.get_by_id(request.id)

        if anno is None:
            raise endpoints.NotFoundException('No anno entity with the id "%s" exists.' % request.id)

        # set anno basic properties
        anno_resp_message = anno.to_response_message(user, list_message=False)

        # set anno association with followups
        followups = FollowUp.find_by_anno(anno)
        followup_messages = [ entity.to_message(team_key=request.team_key) for entity in followups ]
        anno_resp_message.followup_list = followup_messages

        # set anno association with votes/flags
        # if current user exists, then fetch vote/flag.
        if user is not None:
            anno_resp_message.is_my_vote = Vote.is_belongs_user(anno, user)
            anno_resp_message.is_my_flag = Flag.is_belongs_user(anno, user)

            # update last_read of UserAnnoState
            UserAnnoState.update_last_read(user=user, anno=anno)

        return anno_resp_message

 def init_index_document(self, request):
     """
     Exposes an API endpoint to insert search document for legacy documents.
     """
     for anno in Anno.query():
         logging.info("generating search document for anno(%s)." % anno.key.id())
         put_search_document(anno.generate_search_document(), SearchIndexName.ANNO)
     return message_types.VoidMessage()

    def anno_dashboard_list(self, request):
        user = auth_user(self.request_state.headers)

        limit = 10
        if request.limit is not None:
            limit = request.limit

        curs = None
        if request.cursor is not None:
            try:
                curs = Cursor(urlsafe=request.cursor)
            except BadValueError:
                raise endpoints.BadRequestException('Invalid cursor %s.' % request.cursor)

        if request.query_type == AnnoQueryType.MY_MENTIONS:
            return Anno.query_by_my_mentions_for_dashboard(limit, curs, user)
        elif request.query_type == AnnoQueryType.ACTIVITY_COUNT:
            return Anno.query_by_count_for_dashboard(limit, curs, user, request.query_type)
        elif request.query_type == AnnoQueryType.VOTE_COUNT:
            return Anno.query_by_count_for_dashboard(limit, curs, user, request.query_type)
        elif request.query_type == AnnoQueryType.FLAG_COUNT:
            return Anno.query_by_count_for_dashboard(limit, curs, user, request.query_type)
        elif request.query_type == AnnoQueryType.ARCHIVED:
            return Anno.query_by_page_for_dashboard(limit, curs, user, query_by_archived=True)
        elif request.anno_id:
            return Anno.query_by_anno_for_dashboard(user, request.anno_id)
        else:
            return Anno.query_by_page_for_dashboard(limit, curs, user)

    def anno_list(self, request):
        """
        Exposes an API endpoint to retrieve a list of anno.
        """
        user = auth_user(self.request_state.headers)
        limit = 10
        if request.limit is not None:
            limit = request.limit

        curs = None
        if request.cursor is not None:
            try:
                curs = Cursor(urlsafe=request.cursor)
            except BadValueError:
                raise endpoints.BadRequestException('Invalid cursor %s.' % request.cursor)

        select_projection = None
        if request.select is not None:
            select_projection = request.select.split(',')

        if request.query_type == 'by_created':
            return Anno.query_by_app_by_created(request.app, limit, select_projection, curs)
        elif request.query_type == 'by_vote_count':
            return Anno.query_by_vote_count(request.app)
        elif request.query_type == 'by_flag_count':
            return Anno.query_by_flag_count(request.app)
        elif request.query_type == 'by_activity_count':
            return Anno.query_by_activity_count(request.app)
        elif request.query_type == 'by_last_activity':
            return Anno.query_by_last_activity(request.app)
        elif request.query_type == 'by_country':
            return Anno.query_by_country(request.app)
        else:
            return Anno.query_by_page(limit, select_projection, curs)

    def delete_by_anno(cls, anno_id=None, anno_key=None):
        if anno_key is None:
            anno = Anno.get_by_id(anno_id) if anno_id else None
            anno_key = anno.key if anno else None

        if anno_key:
            followups = cls.query(cls.anno_key == anno_key).fetch()
            followup_key_list = [ followup.key for followup in followups ]
            ndb.delete_multi(followup_key_list)

    def delete_by_anno(cls, anno_id=None, anno_key=None):
        if anno_key is None:
            anno = Anno.get_by_id(anno_id) if anno_id else None
            anno_key = anno.key if anno else None

        if anno_key:
            votes = cls.query(cls.anno_key == anno_key).fetch()
            vote_key_list = [ vote.key for vote in votes ]
            ndb.delete_multi(vote_key_list)

    def delete_by_anno(cls, anno_id=None, anno_key=None):
        if anno_key is None:
            anno = Anno.get_by_id(anno_id) if anno_id else None
            anno_key = anno.key if anno else None

        if anno_key:
            userannostates = cls.query(cls.anno == anno_key).fetch()
            userannostate_key_list = [ userannostate.key for userannostate in userannostates ]
            ndb.delete_multi(userannostate_key_list)

    def delete_by_anno(cls, anno_id=None, anno_key=None):
        if anno_key is None:
            anno = Anno.get_by_id(anno_id) if anno_id else None
            anno_key = anno.key if anno else None

        if anno_key:
            flags = cls.query(cls.anno_key == anno_key).fetch()
            flag_key_list = [ flag.key for flag in flags ]
            ndb.delete_multi(flag_key_list)

    def update_notify(self, request):
        user = auth_user(self.request_state.headers)
        anno = Anno.get_by_id(request.anno_id)
        entity = UserAnnoState.get(user=user, anno=anno)

        if entity:
            entity.notify = request.notify
            entity.put()

        return message_types.VoidMessage()