#Sharifah Hana Humaira
#52224122452
#Lab 2 Project Semester 3

import network
import time
import ujson
from machine import Pin
from hcsr04 import HCSR04
from umqtt.simple import MQTTClient

# WiFi parameters
WIFI_SSID = "wokwi-guest"
WIFI_PASSWORD = ""
# MQTT parameters
MQTT_CLIENT_ID = ""
MQTT_BROKER = "mqtt-dashboard.com"
MQTT_USER = ""
MQTT_PASSWORD = ""
MQTT_TOPIC = "wokwi"

# Initialize ultrasonic sensor
sensor = HCSR04(trigger_pin=25, echo_pin=26)

print("Connecting to WiFi", end="")
sta_if = network.WLAN(network.STA_IF)
sta_if.active(True)
sta_if.connect('Wokwi-GUEST','')
while not sta_if.isconnected():
    print(".", end="")
    time.sleep(0.1)
print(" Connected!")

print("Connecting to MQTT server... ", end="")
client = MQTTClient(MQTT_CLIENT_ID, MQTT_BROKER, user=MQTT_USER, password=MQTT_PASSWORD)
client.connect()
print("Connected!")

prev_distance = None
while True:
    print("Measuring distance... ", end="")
    distance_cm = sensor.distance_cm()
    message = ujson.dumps({"distance_cm": distance_cm})
    if distance_cm != prev_distance:
        print("Updated!")
        print("Reporting to MQTT topic {}: {}".format(MQTT_TOPIC, message))
        client.publish(MQTT_TOPIC, message)
        prev_distance = distance_cm
    else:
        print("No change")
    time.sleep(1)