"""Lambda fan-triggered-send-definitions function module."""
from concurrent.futures import ThreadPoolExecutor
import json
import time
import xml.etree.ElementTree as ET

from lambdacommon.common_config import logger
import requests
from sentry_sdk import capture_exception

import config  # noqa
from src import marketing_cloud_messages


def handler(event, context):
    """Lambda entry point."""
    try:
        business_units_xml, triggered_send_definitions_xml = get_business_units_and_triggered_send_definitions()
        response = prepare_response(business_units_xml, triggered_send_definitions_xml)
        return {
            'statusCode': 200,
            'headers': {
                'Content-Type': 'application/json'
            },
            'body': response
        }
    except Exception as e:
        logger.exception(str(e))
        capture_exception(e)
        return {
            'statusCode': 500,
            'body': 'Internal Server Error'
        }


def get_business_units_and_triggered_send_definitions():
    """Get business units and triggered send definitions from the Marketing Cloud API."""
    with ThreadPoolExecutor(max_workers=2) as executor:
        futures = [
            executor.submit(send_marketing_cloud_request, marketing_cloud_messages.BUSINESS_UNITS_MESSAGE),
            executor.submit(send_marketing_cloud_request, marketing_cloud_messages.TRIGGERED_SENDS_MESSAGE),
        ]
        business_units = futures[0].result()
        logger.info('Successfully fetched business units')
        triggered_sends = futures[1].result()
        logger.info('Successfully fetched triggered sends')
        return business_units, triggered_sends


def send_marketing_cloud_request(soap_request_message, max_attempts=3):
    """Get triggered send definitions from the Marketing Cloud API.

    Args:
        soap_request_message (str): The SOAP request message to send to the Marketing Cloud API.
        max_attempts (int): The maximum number of attempts to fetch the data from the API.

    Returns:
        str: The response from the Marketing Cloud API.

    Raises:
        RuntimeError: If request to Marketing Cloud API fails after several attempts.
    """
    attempt = 0
    while attempt < max_attempts:
        try:
            response = requests.post(
                config.MARKETING_CLOUD_SERVICE_API_URL,
                data=soap_request_message,
                headers={
                    'SOAPAction': 'Retrieve',
                    'Content-Type': 'text/xml; charset=utf-8',
                })
            response.raise_for_status()
            return response.text
        except requests.RequestException as e:
            attempt += 1
            if attempt == max_attempts:
                raise RuntimeError(f'Failed to fetch token after {max_attempts} attempts') from e
            retry_in = (2 ** (attempt - 1))
            logger.warning(
                f'Request to Marketing Cloud API failed. Attempt {attempt} of {max_attempts}. '
                f'Failure reason: {e}. Retrying in {retry_in} seconds.')
            time.sleep(retry_in)


def prepare_response(business_units_xml, triggered_send_definitions_xml) -> str:
    """Prepare the triggered send definitions response.

    Args:
        xml (str): The XML response from the Marketing Cloud API.

    Returns:
        str: The JSON response with triggered send definitions.
    """
    bu_root = ET.fromstring(business_units_xml)
    namespaces = {
        'ns': 'http://exacttarget.com/wsdl/partnerAPI'
    }
    business_units = {}
    for elem in bu_root.findall('.//ns:Results', namespaces):
        business_units[elem.find('ns:ID', namespaces).text] = elem.find('ns:Name', namespaces).text

    tsd_root = ET.fromstring(triggered_send_definitions_xml)
    namespaces = {
        'ns': 'http://exacttarget.com/wsdl/partnerAPI'
    }
    triggered_send_definitions = []
    for elem in tsd_root.findall('.//ns:Results', namespaces):
        mid = elem.find('ns:Client/ns:ID', namespaces).text
        triggered_send_definitions.append({
            'MID': mid,
            'BusinessUnitName': business_units.get(mid, ''),
            'TriggerSendDefinitionKey': elem.find('ns:CustomerKey', namespaces).text,
            'TriggerSendDefinitionName': elem.find('ns:Name', namespaces).text
        })
    return json.dumps({'TriggerSends': triggered_send_definitions})