from aws_lambda_powertools import Logger
from aws_lambda_powertools.event_handler.api_gateway import Router
from layercake.dateutils import now
from layercake.dynamodb import DynamoDBPersistenceLayer, KeyPair

from boto3clients import dynamodb_client
from config import ENROLLMENT_TABLE
from exceptions import CancelPolicyConflictError, EnrollmentConflictError
from middlewares.authentication_middleware import User as Authenticated

logger = Logger(__name__)
router = Router()
dyn = DynamoDBPersistenceLayer(ENROLLMENT_TABLE, dynamodb_client)


@router.patch('/<enrollment_id>/cancel')
def cancel(enrollment_id: str):
    now_ = now()
    canceled_by: Authenticated = router.context['user']

    with dyn.transact_writer() as transact:
        transact.update(
            key=KeyPair(enrollment_id, '0'),
            cond_expr='attribute_exists(sk) AND #status = :pending',
            update_expr='SET #status = :canceled, \
                             canceled_at = :now, \
                             updated_at = :now',
            expr_attr_names={
                '#status': 'status',
            },
            expr_attr_values={
                ':pending': 'PENDING',
                ':canceled': 'CANCELED',
                ':now': now_,
            },
            exc_cls=EnrollmentConflictError,
        )
        transact.put(
            item={
                'id': enrollment_id,
                'sk': 'CANCELED',
                'user_id': canceled_by.id,
                'name': canceled_by.name,
                'created_at': now_,
            }
        )
        transact.delete(
            key=KeyPair(enrollment_id, 'CANCEL_POLICY'),
            cond_expr='attribute_exists(sk)',
            exc_cls=CancelPolicyConflictError,
        )