"""Utils."""

from src import lambda_exceptions


def extract_triggered_key(cloudwatch_event):
    """Get S3 bucket and key from CloudWatch event.

    Args:
        cloudwatch_event (dict): AWS CloudWatch event data object.
    Returns:
         (str, str): Tuple of bucket and key names.

    """
    try:
        if cloudwatch_event['detail-type'] == 'Object Created':
            detail = cloudwatch_event['detail']
            bucket_name = detail['bucket']['name']
            key = detail['object']['key']
            return bucket_name, key
        elif cloudwatch_event['detail-type'] == (
                'GuardDuty Malware Protection Object Scan Result'):
            s3_object_details = (
                cloudwatch_event['detail']['s3ObjectDetails'])
            bucket_name = s3_object_details['bucketName']
            key = s3_object_details['objectKey']
            return bucket_name, key
        else:
            # Default to old event structure for backward compatibility
            request_params = cloudwatch_event['detail']['requestParameters']
            bucket_name = request_params['bucketName']
            key = request_params['key']
            return bucket_name, key

    except KeyError as e:
        raise lambda_exceptions.UnexpectedEventBody([str(e)])