"""Connector for SQS service."""

import copy
import decimal
import json
import uuid

from botocore import exceptions

from accounting.flows.reserve_payouts import connectors
from accounting.flows.reserve_payouts import setting
from accounting.flows.reserve_payouts.constants import sqs as sqs_constants
from accounting.util import sqs


def health_check():
    """Perform a simple query to do the health check.

    Returns:
        namedtuple: with bool and message attributes,
            (True, '') if connection is ok,
            (False, 'Error message') otherwise.

    """
    try:
        queue = sqs.get_queue_by_name(setting.SQS_QUEUE)
        sqs.get_queue_number_of_messages(queue)
    except (exceptions.BotoCoreError, exceptions.ClientError) as e:
        result = connectors.HealthCheckResult(False, str(e))
    else:
        result = connectors.HealthCheckResult(True, '')
    return result


def get_queue_message_count():
    """Get the approximate number of messages in the queue.

    Returns:
        int: Approximate number of messages

    """
    queue = sqs.get_queue_by_name(setting.SQS_QUEUE)
    queue.reload()
    return sqs.get_queue_number_of_messages(queue)


def construct_vendor_message(vendor_data):
    """Construct a message for the SQS queue.

    Args:
        vendor_data (dict): message payload (vendor specific data)

    Returns:
        dict: queue.send_message suitable dict

    """
    json_valid_vendor_data = copy.deepcopy(vendor_data)
    for field_name, field_value in json_valid_vendor_data.items():
        if type(field_value) == decimal.Decimal:
            json_valid_vendor_data[field_name] = float(field_value)
    msg = {
        sqs_constants.SQS_MESSAGE_BODY: json.dumps(json_valid_vendor_data),
        sqs_constants.SQS_MESSAGE_ID: str(uuid.uuid4()),
    }
    return msg


def batch_vendor_send_messages(message_list):
    """Send vendor data messages to SQS in batch.

    Args:
        message_list (list): vendor transactions sum and contract terms

    """
    queue = sqs.get_queue_by_name(setting.SQS_QUEUE)
    sublists_generator = sqs.yield_sublists(
        message_list, setting.SQS_MAX_BATCH_SIZE)
    for sublist in sublists_generator:
        res = queue.send_messages(Entries=sublist)
        # according to boto3 documentation, sqs can contain failed items
        if 'Failed' in res:
            response_str = json.dumps(res)
            msg = 'Failures detected in SQS response: {}'.format(response_str)
            raise Exception(msg)


def get_message():
    """Receive a message from the queue.

    Returns:
        boto3.resources.factory.sqs.Message: SQS message or None

    """
    queue = sqs.get_queue_by_name(setting.SQS_QUEUE)
    queue.set_attributes(
        Attributes={'VisibilityTimeout': str(setting.SQS_VISIBILITY_TIMEOUT)})
    return sqs.get_message(queue)