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# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.

from __future__ import annotations

from typing import List, Optional, Tuple, TYPE_CHECKING, Union

from flask import current_app, g

from superset.tasks.exceptions import ExecutorNotFoundError
from superset.tasks.types import ExecutorType

if TYPE_CHECKING:
    from superset.models.dashboard import Dashboard
    from superset.models.slice import Slice
    from superset.reports.models import ReportSchedule


# pylint: disable=too-many-branches
def get_executor(
    executor_types: List[ExecutorType],
    model: Union[Dashboard, ReportSchedule, Slice],
    current_user: Optional[str] = None,
) -> Tuple[ExecutorType, str]:
    """
    Extract the user that should be used to execute a scheduled task. Certain executor
    types extract the user from the underlying object (e.g. CREATOR), the constant
    Selenium user (SELENIUM), or the user that initiated the request.

    :param executor_types: The requested executor type in descending order. When the
           first user is found it is returned.
    :param model: The underlying object
    :param current_user: The username of the user that initiated the task. For
           thumbnails this is the user that requested the thumbnail, while for alerts
           and reports this is None (=initiated by Celery).
    :return: User to execute the report as
    :raises ScheduledTaskExecutorNotFoundError: If no users were found in after
            iterating through all entries in `executor_types`
    """
    owners = model.owners
    owner_dict = {owner.id: owner for owner in owners}
    for executor_type in executor_types:
        if executor_type == ExecutorType.SELENIUM:
            return executor_type, current_app.config["THUMBNAIL_SELENIUM_USER"]
        if executor_type == ExecutorType.CURRENT_USER and current_user:
            return executor_type, current_user
        if executor_type == ExecutorType.CREATOR_OWNER:
            if (user := model.created_by) and (owner := owner_dict.get(user.id)):
                return executor_type, owner.username
        if executor_type == ExecutorType.CREATOR:
            if user := model.created_by:
                return executor_type, user.username
        if executor_type == ExecutorType.MODIFIER_OWNER:
            if (user := model.changed_by) and (owner := owner_dict.get(user.id)):
                return executor_type, owner.username
        if executor_type == ExecutorType.MODIFIER:
            if user := model.changed_by:
                return executor_type, user.username
        if executor_type == ExecutorType.OWNER:
            owners = model.owners
            if len(owners) == 1:
                return executor_type, owners[0].username
            if len(owners) > 1:
                if modifier := model.changed_by:
                    if modifier and (user := owner_dict.get(modifier.id)):
                        return executor_type, user.username
                if creator := model.created_by:
                    if creator and (user := owner_dict.get(creator.id)):
                        return executor_type, user.username
                return executor_type, owners[0].username

    raise ExecutorNotFoundError()


def get_current_user() -> Optional[str]:
    user = g.user if hasattr(g, "user") and g.user else None
    if user and not user.is_anonymous:
        return user.username

    return None