#
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# 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

import logging
import os
import pathlib
import shutil
from functools import cached_property
from typing import TYPE_CHECKING

import attrs

from airflow.providers.amazon.aws.hooks.s3 import S3Hook
from airflow.providers.amazon.version_compat import AIRFLOW_V_3_0_PLUS
from airflow.providers.common.compat.sdk import conf
from airflow.utils.log.file_task_handler import FileTaskHandler
from airflow.utils.log.logging_mixin import LoggingMixin

if TYPE_CHECKING:
    from airflow.models.taskinstance import TaskInstance
    from airflow.sdk.types import RuntimeTaskInstanceProtocol as RuntimeTI
    from airflow.utils.log.file_task_handler import LogMessages, LogSourceInfo


@attrs.define
class S3RemoteLogIO(LoggingMixin):  # noqa: D101
    remote_base: str
    base_log_folder: pathlib.Path = attrs.field(converter=pathlib.Path)
    delete_local_copy: bool

    processors = ()

    def upload(self, path: os.PathLike | str, ti: RuntimeTI):
        """Upload the given log path to the remote storage."""
        path = pathlib.Path(path)
        if path.is_absolute():
            local_loc = path
            remote_loc = os.path.join(self.remote_base, path.relative_to(self.base_log_folder))
        else:
            local_loc = self.base_log_folder.joinpath(path)
            remote_loc = os.path.join(self.remote_base, path)

        if local_loc.is_file():
            # read log and remove old logs to get just the latest additions
            log = local_loc.read_text()
            has_uploaded = self.write(log, remote_loc)
            if has_uploaded and self.delete_local_copy:
                shutil.rmtree(os.path.dirname(local_loc))
            elif has_uploaded:
                local_loc.write_text("")

    @cached_property
    def hook(self):
        """Returns S3Hook."""
        return S3Hook(
            aws_conn_id=conf.get("logging", "REMOTE_LOG_CONN_ID"),
            transfer_config_args={"use_threads": False, "preferred_transfer_client": "classic"},
        )

    def s3_log_exists(self, remote_log_location: str) -> bool:
        """
        Check if remote_log_location exists in remote storage.

        :param remote_log_location: log's location in remote storage
        :return: True if location exists else False
        """
        return self.hook.check_for_key(remote_log_location)

    def s3_read(self, remote_log_location: str, return_error: bool = False) -> str:
        """
        Return the log found at the remote_log_location or '' if no logs are found or there is an error.

        :param remote_log_location: the log's location in remote storage
        :param return_error: if True, returns a string error message if an
            error occurs. Otherwise returns '' when an error occurs.
        :return: the log found at the remote_log_location
        """
        try:
            return self.hook.read_key(remote_log_location)
        except Exception as error:
            msg = f"Could not read logs from {remote_log_location} with error: {error}"
            self.log.exception(msg)
            # return error if needed
            if return_error:
                return msg
        return ""

    def write(
        self,
        log: str,
        remote_log_location: str,
        append: bool = True,
        max_retry: int = 1,
    ) -> bool:
        """
        Write the log to the remote_log_location; return `True` or fails silently and return `False`.

        :param log: the contents to write to the remote_log_location
        :param remote_log_location: the log's location in remote storage
        :param append: if False, any existing log file is overwritten. If True,
            the new log is appended to any existing logs.
        :param max_retry: Maximum number of times to retry on upload failure
        :return: whether the log is successfully written to remote location or not.
        """
        try:
            if append and self.s3_log_exists(remote_log_location):
                old_log = self.s3_read(remote_log_location)
                if old_log:
                    sep = "" if old_log.endswith("\n") else "\n"
                    log = f"{old_log}{sep}{log}"
        except Exception:
            self.log.exception("Could not verify previous log to append")
            return False

        # Default to a single retry attempt because s3 upload failures are
        # rare but occasionally occur.  Multiple retry attempts are unlikely
        # to help as they usually indicate non-ephemeral errors.
        for try_num in range(1 + max_retry):
            try:
                self.hook.load_string(
                    log,
                    key=remote_log_location,
                    replace=True,
                    encrypt=conf.getboolean("logging", "ENCRYPT_S3_LOGS"),
                )
                break
            except Exception:
                if try_num < max_retry:
                    self.log.warning(
                        "Failed attempt to write logs to %s, will retry",
                        remote_log_location,
                    )
                else:
                    self.log.exception("Could not write logs to %s", remote_log_location)
                    return False
        return True

    def read(self, relative_path: str, ti: RuntimeTI) -> tuple[LogSourceInfo, LogMessages | None]:
        logs: list[str] = []
        messages = []
        bucket, prefix = self.hook.parse_s3_url(s3url=os.path.join(self.remote_base, relative_path))
        keys = self.hook.list_keys(bucket_name=bucket, prefix=prefix)
        if keys:
            keys = sorted(f"s3://{bucket}/{key}" for key in keys)
            if AIRFLOW_V_3_0_PLUS:
                messages = keys
            else:
                messages.append("Found logs in s3:")
                messages.extend(f"  * {key}" for key in keys)
            for key in keys:
                logs.append(self.s3_read(key, return_error=True))
            return messages, logs
        return messages, None


class S3TaskHandler(FileTaskHandler, LoggingMixin):
    """
    S3TaskHandler is a python log handler that handles and reads task instance logs.

    It extends airflow FileTaskHandler and uploads to and reads from S3 remote storage.
    """

    def __init__(
        self,
        base_log_folder: str,
        s3_log_folder: str,
        max_bytes: int = 0,
        backup_count: int = 0,
        delay: bool = False,
        **kwargs,
    ) -> None:
        # support log file size handling of FileTaskHandler
        super().__init__(
            base_log_folder=base_log_folder, max_bytes=max_bytes, backup_count=backup_count, delay=delay
        )
        self.handler: logging.FileHandler | None = None
        self.remote_base = s3_log_folder
        self.log_relative_path = ""
        self._hook = None
        self.closed = False
        self.upload_on_close = True
        self.io = S3RemoteLogIO(
            remote_base=s3_log_folder,
            base_log_folder=base_log_folder,
            delete_local_copy=kwargs.get(
                "delete_local_copy", conf.getboolean("logging", "delete_local_logs")
            ),
        )

    def set_context(self, ti: TaskInstance, *, identifier: str | None = None) -> None:
        super().set_context(ti, identifier=identifier)
        # Local location and remote location is needed to open and
        # upload local log file to S3 remote storage.
        if TYPE_CHECKING:
            assert self.handler is not None

        self.ti = ti

        full_path = self.handler.baseFilename
        self.log_relative_path = pathlib.Path(full_path).relative_to(self.local_base).as_posix()
        is_trigger_log_context = getattr(ti, "is_trigger_log_context", False)
        self.upload_on_close = is_trigger_log_context or not getattr(ti, "raw", None)
        # Clear the file first so that duplicate data is not uploaded
        # when reusing the same path (e.g. with rescheduled sensors)
        if self.upload_on_close:
            with open(self.handler.baseFilename, "w"):
                pass

    def close(self):
        """Close and upload local log file to remote storage S3."""
        # When application exit, system shuts down all handlers by
        # calling close method. Here we check if logger is already
        # closed to prevent uploading the log to remote storage multiple
        # times when `logging.shutdown` is called.
        if self.closed:
            return

        super().close()

        if not self.upload_on_close:
            return

        if hasattr(self, "ti"):
            self.io.upload(self.log_relative_path, self.ti)

        # Mark closed so we don't double write if close is called twice
        self.closed = True

    def _read_remote_logs(self, ti, try_number, metadata=None) -> tuple[LogSourceInfo, LogMessages]:
        # Explicitly getting log relative path is necessary as the given
        # task instance might be different than task instance passed in
        # in set_context method.
        worker_log_rel_path = self._render_filename(ti, try_number)

        messages, logs = self.io.read(worker_log_rel_path, ti)

        if logs is None:
            logs = []
            if not AIRFLOW_V_3_0_PLUS:
                messages.append(f"No logs found on s3 for ti={ti}")

        return messages, logs
