import boto3
from queue import Queue
from threading import Event
import logging
import time
from sorteerhoed.Signal import Signal

class SqsListener:
    def __init__(self, config, eventQ: Queue, runningEvent: Event):
        self.isRunning = runningEvent
        self.eventQ = eventQ
        self.config = config
        self.logger = logging.getLogger('sorteerhoed').getChild('sqs')
        
    def start(self):
        # create a boto3 client
        sqs = boto3.client('sqs',
           aws_access_key_id = self.config['amazon']['user_id'],
           aws_secret_access_key = self.config['amazon']['user_secret'],
           region_name=self.config['amazon']['sqs_region_name'],
           endpoint_url=self.config['amazon']['sqs_endpoint_url']
        )

        while self.isRunning.is_set():
            messages = sqs.receive_message(
                QueueUrl=self.config['amazon']['sqs_url'],
                MaxNumberOfMessages=1,
                WaitTimeSeconds=20)
            if 'Messages' in messages: # when the queue is exhausted, the response dict contains no 'Messages' key
                for message in messages['Messages']: # 'Messages' is a list
                    # process the messages
                    self.debug(f"received: {message}")
                    try:
                        for event in message['Body']['Events']:
                            self.eventQ.put(Signal(
                                f"sqs.{event['EventType']}",
                                {'event': event}
                            ))
                    except Exception:
                        pass
                    # next, we delete the message from the queue so no one else will process it again
                    sqs.delete_message(
                        QueueUrl=self.config['amazon']['sqs_url'],
                        ReceiptHandle=message['ReceiptHandle']
                    )
            else:
                self.logger.debug('SQS is empty')
                time.sleep(1)
        self.logger.info("Stopping SQS")