import json
from urllib2 import Request, urlopen, URLError, HTTPError
import logging

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

slack_hook_url = "<ADD SLACK WEBHOOK URL HERE>" #get yours from the incoming webhooks you created in Slack
display_username = "GitHub Alert from repo" #repo name will be tacked onto the end of this
display_emoji = ":speak_no_evil:" #change the emoji from the list @ http://www.emoji-cheat-sheet.com/

def lambda_handler(event, context):

    #get the values we want from the GitHub pull request payload (https://developer.github.com/v3/activity/events/types/#pullrequestevent)
    username = event['pull_request']['user']['login']
    repotitle = event['pull_request']['title']
    actionmess = event['action']
    pullrequestnum = event['number']
    reponame = event['pull_request']['head']['repo']['name']
    pullrequesturl = event['pull_request']['html_url']

    #create the slack message
    slack_message = {
        'text': "%s - %s pull request <%s|#%s> from %s"%(username, actionmess, pullrequesturl, str(pullrequestnum), reponame),
        'username' : "%s %s"%(display_username, reponame),
        'icon_emoji' : display_emoji
    }

    #send the message to slack
    try:
        req = Request(slack_hook_url, json.dumps(slack_message))
        response = urlopen(req)
        response.read()
        logger.info(slack_message) 
    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 None