"""Lambda function module."""
import boto3
import sqlalchemy
from vector_utils.aws_utils import sqs

import config
from src import logger, sql_queries
from src.connectors import art_relations


def select_and_add_upcs_to_sqs(event_detail_type, log=None):
    """Select unused upcs and add them to upc_repository-queue."""
    sqs_client = boto3.client('sqs', region_name='us-east-1')

    response = sqs_client.get_queue_attributes(
        QueueUrl=config.QUEUE_NAME_UPC_PROVISIONER,
        AttributeNames=['ApproximateNumberOfMessages']
    )

    current_messages_in_queue = int(
        response['Attributes']['ApproximateNumberOfMessages']
    )

    # If there are more upcs in queue then our threshold we want to set to 0 instead of -n
    needed_upcs = max(
        config.UPCS_AR_SELECT_LIMIT_ALARM - current_messages_in_queue,
        0
    )

    if needed_upcs == 0:
        log.info('No upcs needed')
        return

    with art_relations.session_scope() as session:
        result_select = session.execute(
            sqlalchemy.text(sql_queries.SELECT_UPCS),
            {
                'limit': needed_upcs,
                'offset': config.UPCS_AR_SELECT_OFFSET
            })
        upc_list = [row['upc'] for row in result_select]

        session.execute(
            sqlalchemy.text(sql_queries.UPDATE_STATUS),
            {
                'list': upc_list
            })

        log.info(f'Number of UPCs claimed: {len(upc_list)}')
    return sqs.add_messages_to_sqs(
        config.QUEUE_NAME_UPC_PROVISIONER, upc_list)


def handler(event, context):
    """Lambda entry point."""
    log = logger.get_current_logger()
    event_detail_type = event.get('detail-type')
    sqs_response = select_and_add_upcs_to_sqs(event_detail_type, log)
    log.info('SQS response after pushing to queue: ', sqs_response)
    return sqs_response