#!/usr/bin/env python3

# ------------------------------------------------------------------------------
# MQTTWatcher
# Marco Panato 2018/01/13
#
# Simple utility that can monitor topics on a broker and notify users with
# messages sent by a telegram bot.
# ------------------------------------------------------------------------------


import ssl
import time
import telegram                 # sudo pip3 install python-telegram-bot
import paho.mqtt.client as mqtt # sudo pip3 install paho-mqtt


# ------------------------------------------------------------------------------
# Params

TELEGRAM_BOT_TOKEN = 'TOKEN'

# Mqtt broker address and port
MQTT_BROKER_ADDR = 'ADDRESS'
MQTT_BROKER_PORT = 1883

# Mqtt broker credentials, comment these lines if anonymous access is granted
#MQTT_BROKER_USERNAME = 'USERNAME'
#MQTT_BROKER_PASSWORD = 'PASSWORD'

# Mqtt broker ssl
MQTT_BROKER_SSL_ENABLED = False
MQTT_BROKER_SSL_CA_PATH = ''
MQTT_BROKER_SSL_CERT_PATH = ''
MQTT_BROKER_SSL_KEY_PATH = ''

# A list of topics to subscribe to
TOPIC_TO_WATCH = [
    'prova/topic1'
]

# Telegram (user-id:username) tuple list
USERS_TO_NOTIFY = [
    (33343434, 'USERNAME 1') # 33343434 is a RANDOM userid
]
# ------------------------------------------------------------------------------


# ------------------------------------------------------------------------------
# Mqtt callbacks
def on_message(mqttc, userdata, message):
    print('[TOPIC] Topic %s changed to %s!' % (message.topic, str(message.payload)))
    text = 'MqttWatcher\n%s : %s' % (message.topic,str(message.payload))
    for user in USERS_TO_NOTIFY:
        print('[MQTT] Notifying %s' % user[1])
        userdata.send_message(chat_id=user[0], text=text)


def on_connect(mqttc, userdata, flags, rc):
    print("[MQTT] Connected with result code "+str(rc))

    # Subscribing in on_connect() means that if we lose the connection and
    # reconnect then subscriptions will be renewed.
    for topic in TOPIC_TO_WATCH:
        print('[MQTT] Subscribing to topic: %s' % topic)
        mqttc.subscribe(topic, 0)


def on_disconnect(mqttc, userdata, rc):
    print('[MQTT] Connection closed!')
    if rc != 0:
        print('[MQTT] Trying to reconnect...')
# ------------------------------------------------------------------------------

# ------------------------------------------------------------------------------
# Main loop
if __name__ == '__main__':
    print('MQTT Topic Watcher\nMarco Panato 2018/01/13')

    # Telegram bot
    print('[MAIN] Initializing TelegramBot')
    telegrambot = telegram.Bot(token=TELEGRAM_BOT_TOKEN)

    # Mqtt client
    print('[MAIN] Initializing MQTT Client')
    mqttc = mqtt.Client(userdata = telegrambot)
    mqttc.on_connect = on_connect
    mqttc.on_disconnect = on_disconnect
    mqttc.on_message = on_message
    if 'MQTT_BROKER_USERNAME' in dir() and 'MQTT_BROKER_PASSWORD' in dir():
        print('[MAIN] Setting username and password for MQTT')
        mqttc.username_pw_set(MQTT_BROKER_USERNAME, MQTT_BROKER_PASSWORD)
    if MQTT_BROKER_SSL_ENABLED:
        print('[MAIN] Enabling SSL support for MQTT')
        mqttc.tls_set(ca_certs=MQTT_BROKER_SSL_CA_PATH, certfile=MQTT_BROKER_SSL_CERT_PATH, keyfile=MQTT_BROKER_SSL_KEY_PATH, cert_reqs=ssl.CERT_NONE)
    mqttc.connect(MQTT_BROKER_ADDR, MQTT_BROKER_PORT)

    # Main loop
    mqttc.loop_start()
    print('[MAIN] App ready! Press CTRL-C to quit...')
    try:
        while True:
            time.sleep(100)
    except KeyboardInterrupt:
        pass

    print('[MAIN] Quitting...')
    mqttc.loop_stop()
    mqttc.disconnect()
# ------------------------------------------------------------------------------