"""Lambda pp_identity function module."""
from kafka_utils.producer.event import EventProducer
from kafka_utils.producer.serializer.simple_json import SimpleJSONSerializer
from lambdacommon.common_config import logger
import config


def handler(event, context):
    """Lambda entry point."""
    try:
        produce_records_to_kafka(event['Records'])
        return {'status': 'OK'}
    except Exception as e:
        logger.exception(str(e))
        raise e


def produce_records_to_kafka(records: list[dict]):
    """Produce records to Kafka.

    Args:
        records: All records received from DynamoDB Streams trigger.
    """
    with EventProducer(
            bootstrap_servers=config.KAFKA_BOOTSTRAP_SERVERS,
            value_serializer=SimpleJSONSerializer(),
            security_protocol=config.KAFKA_SECURITY_PROTOCOL
    ) as producer:
        for record in records:
            transformed_record = transform(record)
            producer.produce(
                topic=config.KAFKA_TARGET_TOPIC,
                event_key=None,
                event_value=transformed_record,
                auto_flush=False
            )


def transform(item: dict):
    """Transform record to camel-aws-ddb-streams-source Kafka Connector format.

    This recursive function walks through the record and does the following:
    - Converts keys from Pascal Case to Camel Case
    - Adds a 'type' key to the DynamoDB items

    Args:
        item: Record to transform.

    Returns:
        dict: Transformed record.
    """
    if isinstance(item, dict):
        # d = {_change_key_case(k): transform(v) for k, v in item.items()}
        d = {}
        for k, v in item.items():
            if k == 'ApproximateCreationDateTime':
                v = int(v * 1000)
            d[_change_key_case(k)] = transform(v)
        if len(d) == 1:
            key = list(item.keys())[0]
            if key.upper() in config.DYNAMODB_DATA_TYPES:
                d['type'] = key
                for k, v in config.CAMEL_CONNECTOR_DEFAULT_ATTRIBUTES.items():
                    if k not in d:
                        d[k] = v
        return d
    elif isinstance(item, list):
        return [transform(i) for i in item]
    else:
        return item


def _change_key_case(key):
    if key in config.DYNAMODB_DATA_TYPES:
        return key.lower()
    return key[0].lower() + key[1:]