"""Lambda data-alarm-slack function module."""

from __future__ import print_function

import json
import logging
import urllib

import config

from urllib.request import urlopen
from urllib.error import HTTPError
from urllib.error import URLError

logger = logging.getLogger()
logger.setLevel(logging.INFO)


def handler(event, context):
    """Lambda entry point."""
    logger.info('Event: ' + str(event))
    for record in event['Records']:
        message = record['Sns']['Message']
        logger.info('Message: ' + str(message))

        alarm_name = message['AlarmName']
        new_state = message['NewStateValue']
        reason = message['NewStateReason']

        slack_message = {
            'channel': config.SLACK_CHANNEL,
            'text': '%s state is now %s: %s' % (alarm_name, new_state, reason)
        }

        req = urllib.request.Request(config.HOOK_URL, json.dumps(slack_message)
                                     .encode('utf-8'))
        try:
            response = urlopen(req)
            response.read()
            logger.info('Message posted to %s', slack_message['channel'])
        except HTTPError as e:
            logger.error('Request failed: %d %s', e.code, e.reason)
        except URLError as e:
            logger.error('Server connection failed: %s', e.reason)

    return {'status': 'OK'}