import logging
from datetime import timedelta

from alibabacloud_tea_openapi.models import Config as AlicloudConfig
from alibabacloud_ros20190910.client import Client as AlicloudROSClient
from alibabacloud_ros20190910.models import (
    DeleteStackRequest,
    ListStacksRequest,
)
from celery import shared_task
from django.conf import settings
from django.utils import timezone

from labs.models import LabInstance as DBLabInstance

logger = logging.getLogger(__name__)


ALICLOUD_REGIONS = [
    "ap-southeast-1",
]


@shared_task
def alicloud_ros_housekeeping():
    """
    Fallback cleanup task for Alibaba Cloud ROS stacks.

    Purpose:
    - Acts as a safety net when a Lab Instance is not properly destroyed.
    - Scans configured regions and removes orphaned/expired stacks tied to lab instances.
    - Reduces cost by preventing unused resources from lingering.
    """
    for region in ALICLOUD_REGIONS:
        _alicloud_ros_housekeeping(region)


def _alicloud_ros_housekeeping(region: str):
    client = AlicloudROSClient(
        config=AlicloudConfig(
            access_key_id=settings.ALICLOUD_ROS_ACCESS_KEY_ID,
            access_key_secret=settings.ALICLOUD_ROS_ACCESS_KEY_SECRET,
            region_id=region,
        )
    )
    page_size = 50
    page_number = 1
    while True:
        response = client.list_stacks(
            request=ListStacksRequest(
                region_id=region,
                page_size=page_size,
                page_number=page_number,
            )
        )
        stacks = response.body.stacks
        for stack in stacks:
            stack_id = stack.stack_id
            stack_name = stack.stack_name
            stack_status = stack.status

            try:
                DBLabInstance.objects.get(
                    unique_tag=stack_name,
                    scheduled_terminate_at__lt=timezone.now()
                    # subtract 10 minutes to give normal recycle task time to execute;
                    # this housekeeping task is a final safety net if recycle fails
                    - timedelta(minutes=10),
                )
            except DBLabInstance.DoesNotExist:
                continue

            match stack_status:
                case "CREATE_COMPLETE" | "CREATE_FAILED":
                    logger.info(
                        f"Housekeeping[{region}]: Deleting stack {stack_name} in status {stack_status}"
                    )
                    try:
                        client.delete_stack(
                            request=DeleteStackRequest(
                                region_id=region,
                                stack_id=stack_id,
                            )
                        )
                    except Exception as e:
                        logger.error(
                            f"Housekeeping[{region}]: Failed to delete stack {stack_name}: {e}"
                        )
                case "DELETE_FAILED":
                    logger.error(
                        f"Housekeeping[{region}]: Find a stack in DELETE_FAILED status: {stack_name}, "
                        "please check manually"
                    )
                case _:
                    continue

        total_count = response.body.total_count
        if page_number * page_size >= total_count:
            break
        page_number += 1