#03-welcome_message.py

import requests
from time import sleep

global OFFSET
OFFSET = 0

botToken = ""

global requestURL
global sendURL

requestURL = "http://api.telegram.org/bot" + botToken + "/getUpdates"
sendURL = "http://api.telegram.org/bot" + botToken + "/sendMessage"
print (requestURL)


def update (url):
    global OFFSET

    try:
        update_raw = requests.get(url + "?offset=" + str(OFFSET))
        update = update_raw.json()
        result = extract_result(update)

        if result != False:
            OFFSET = result['update_id'] + 1
            return result
        else:
            return False

    except requests.exceptions.ConnectionError:
        pass

def extract_result (dict):
    result_array = dict['result']

    if result_array == []:
        return False
    else:
        result_dic = result_array[0]
        return result_dic


def send_message (chatId, message):
    requests.post(sendURL + "?chat_id=" + str(chatId) + "&text=" + message)


while True:
    newmessage = update (requestURL)

    if newmessage != False:
        chattype = newmessage['message']['chat']['type']
        if  chattype == "group":
            if 'new_chat_participant' in newmessage['message']:
                membername = newmessage['message']['new_chat_participant']['first_name']
                chatid = newmessage['message']['chat']['id']
                send_message(chatid, "Herzlich willkommen, " + membername + " !")
      

    sleep (1)