"""Start SFN execution."""

import json
import time
import uuid

import boto3
from kafka_utils.consumer.deserializer.avro import AvroDeserializer
from kafka_utils.consumer.source.mapping import EventSourceMessage
from lambdacommon.common_config import logger
import config


def start_sfn_execution(event):
    """Start SFN execution."""
    logger.info(f'Extracting product id from event: {event}.')
    product_id = _get_product_id_from_event(event)
    logger.info(f'Starting SFN execution for product id: {product_id}.')
    execution_info = _start_execution(product_id)
    logger.info(f'Started SFN execution with '
                f'ARN: {execution_info["executionArn"]} '
                f'at {execution_info["startDate"]}.')
    return execution_info


def _get_product_id_from_event(event):
    """Get product id from the event."""
    _, msk_message = next(iter(EventSourceMessage(event)))
    deserializer = AvroDeserializer(schema_registry_url=config.SCHEMA_REGISTRY_URL)
    event_value = deserializer.deserialize(msk_message.value, msk_message.topic, 'value')
    return event_value['payload']['product_id']


def _start_execution(product_id: int):
    """Start SFN execution."""
    stepfunctions_client = boto3.client('stepfunctions', region_name=config.AWS_REGION)
    execution_name = f'product_id_{product_id}_timestamp_{int(time.time())}'
    response = stepfunctions_client.start_execution(
        stateMachineArn=config.STEP_FUNCTIONS_ARN,
        name=execution_name,
        input=json.dumps({'product_id': product_id}),
        traceHeader=f'Root=mcc-{uuid.uuid4()};Sampled=1')
    return response