"""Handle DynamoDB Streams events.

1. Read a set of DDB Streams events.
2. Execute other lambda to handle event.
"""

import json

import boto3
from sentry_sdk import capture_exception
from src import config
from constants import fields


def handler(event, context):
    """Handle dynamoDB events, for each call the Lambda that saves to DD DB."""
    try:
        if event is None or fields.DDB_EVENT_RECORDS not in event:
            return
        client = boto3.client('lambda')
        for record in event[fields.DDB_EVENT_RECORDS]:
            # Get a part of the current record with new values only.
            if fields.DDB_EVENT_RECORD_MAIN not in record:
                continue
            ddb = record[fields.DDB_EVENT_RECORD_MAIN]
            if fields.DDB_EVENT_RECORD_NEW_VALUES not in ddb:
                continue
            new_item = ddb[fields.DDB_EVENT_RECORD_NEW_VALUES]
            config.logger.info('Processing record: %s', new_item)
            # Using synchronous (blocking) invocation here is important - we want
            # to save incoming events/records preserving the order.
            client.invoke(
                FunctionName=config.VO_TO_DD_SYNC_LAMBDA_NAME,
                Payload=json.dumps(new_item).encode()
            )
    except Exception as e:
        capture_exception(e)
        raise e