from confluent_kafka import Producer
import json
import logging
from app.config import settings

logger = logging.getLogger(__name__)

class KafkaIntegration:
    _producer = None
    _config = {
        'bootstrap.servers': settings.KAFKA_BROKER,
        'client.id': 'loan-service-producer',
        'acks': 'all',
        'retries': 3
    }


    @staticmethod
    def _get_producer():
        """Kafka producer"""
        if not KafkaIntegration._producer:
            KafkaIntegration._producer = Producer(KafkaIntegration._config)
            logger.info(f"Connected to Kafka broker at {KafkaIntegration._config['bootstrap.servers']}")

        return KafkaIntegration._producer
    


    @staticmethod
    def delivery_report(err, msg):
        """Called once for each message produced"""
        if err is not None:
            logger.error(f'Message delivery failed: {err}')

            raise RuntimeError(f"Message delivery failed: {err}")
        
        else:
            logger.debug(f'Message delivered to {msg.topic()} [{msg.partition()}] @ offset {msg.offset()}')




    @staticmethod
    def send_loan_request(loan_data, request_id):
        """
        Send loan request to PROCESS_PAYMENT topic
        
        Args:
            loan_data: Loan request payload as dict
            request_id: Unique request identifier (used as Kafka key)
        """
        try:
         

            # Proceed to send loan request to Kafka
            producer = KafkaIntegration._get_producer()

            # Sending loan request message to Kafka
            producer.produce(
                topic="PROCESS_PAYMENT",
                key=str(request_id),
                value=json.dumps(loan_data).encode('utf-8'),
                callback=KafkaIntegration.delivery_report
            )
            producer.poll(0)
            logger.info(f"Loan request {request_id} queued for processing")

        except Exception as e:
            logger.error(f"Failed to send loan request to Kafka: {str(e)}", exc_info=True)
            raise Exception(f"Failed to send loan request to Kafka: {str(e)}")


    @staticmethod
    def flush():
        """Shutdown"""
        producer = KafkaIntegration._get_producer()
        producer.flush()