<gh_stars>10-100
"""
Book: Hands-On MQTT Programming with Python
Author: <NAME> - Twitter.com/gastonhillar
Publisher: Packt Publishing Ltd. - http://www.packtpub.com
"""
from config import *
from vehicle_commands import *
import paho.mqtt.client as mqtt
import time
import json


vehicle_name = "vehiclepi01"
commands_topic = "vehicles/{}/commands".format(vehicle_name)
processed_commands_topic = "vehicles/{}/executedcommands".format(vehicle_name)


class LoopControl:
    is_last_command_processed = False


def on_connect(client, userdata, flags, rc):
    print("Result from connect: {}".format(
        mqtt.connack_string(rc)))
    # Check whether the result form connect is the CONNACK_ACCEPTED connack code
    if rc == mqtt.CONNACK_ACCEPTED:
        # Subscribe to the commands topic filter
        client.subscribe(
            processed_commands_topic, 
            qos=2)


def on_message(client, userdata, msg):
    if msg.topic == processed_commands_topic:
        print(str(msg.payload))
        if str(msg.payload).count(CMD_TURN_OFF_ENGINE) > 0:
            LoopControl.is_last_command_processed = True


def on_subscribe(client, userdata, mid, granted_qos):
    print("Subscribed with QoS: {}".format(granted_qos[0]))


def build_command_message(command_name, key="", value=""):
    if key:
        # The command requires a key
        command_message = json.dumps({
            COMMAND_KEY: command_name,
            key: value})
    else:
        # The command doesn't require a key
        command_message = json.dumps({
            COMMAND_KEY: command_name})
    return command_message

def publish_command(client, command_name, key="", value=""):
    command_message = build_command_message(
        command_name, key, value)
    result = client.publish(topic=commands_topic,
                            payload=command_message, qos=2)
    client.loop()
    time.sleep(1)
    return result


if __name__ == "__main__":
    client = mqtt.Client(protocol=mqtt.MQTTv311)
    client.on_connect = on_connect
    client.on_subscribe = on_subscribe
    client.on_message = on_message
    client.tls_set(ca_certs = ca_certificate,
        certfile=client_certificate,
        keyfile=client_key)
    # Set a will to be sent to the MQTT server in case the client
    # disconnects unexpectedly
    last_will_payload = build_command_message(CMD_PARK_IN_SAFE_PLACE)
    client.will_set(topic=commands_topic, 
        payload=last_will_payload, 
        qos=2)
    client.connect(host=mqtt_server_host,
       port=mqtt_server_port,
       keepalive=mqtt_keepalive)
    publish_command(client, CMD_SET_MAX_SPEED, KEY_MPH, 30)
    publish_command(client, CMD_SET_MIN_SPEED, KEY_MPH, 8)
    publish_command(client, CMD_LOCK_DOORS)
    publish_command(client, CMD_TURN_ON_ENGINE)
    publish_command(client, CMD_ROTATE_RIGHT, KEY_DEGREES, 15)
    publish_command(client, CMD_ACCELERATE)
    publish_command(client, CMD_ROTATE_RIGHT, KEY_DEGREES, 25)
    publish_command(client, CMD_ACCELERATE)
    publish_command(client, CMD_ROTATE_LEFT, KEY_DEGREES, 15)
    publish_command(client, CMD_ACCELERATE)
    publish_command(client, CMD_TURN_OFF_ENGINE)
    while LoopControl.is_last_command_processed == False:
        # Process messages and the commands every 500 milliseconds 
        client.loop()
        time.sleep(0.5)
    client.disconnect()
    client.loop()
