print("SMART CLASSROOM SYSTEM - SCADA EDITION")
print("BY: SOUKAINA MALAK HAFIDA")

import network
from machine import Pin, PWM
import dht
from utime import sleep, ticks_ms
from umqtt.simple import MQTTClient
import ujson

# ================= MQTT CONFIG =================
MQTT_BROKER    = "broker.hivemq.com"
MQTT_CLIENT_ID = "ESP32_SmartClass_SOUKAINA"
MQTT_TOPIC     = "hackathon/team:SOUKAINA/salle1/data"
MQTT_STATUS    = "hackathon/team:SOUKAINA/salle1/status"
MQTT_CONTROL   = "hackathon/team:SOUKAINA/salle1/control"

# ================= HARDWARE =================
PIR_sensor   = Pin(13, Pin.IN)
Green_led   = Pin(4, Pin.OUT)
Red_led     = Pin(2, Pin.OUT)
Buzzer      = PWM(Pin(18))
dht_sensor  = dht.DHT22(Pin(26))

# ================= TEMPERATURE LIMITS =================
TEMP_MAX = 30  # °C
TEMP_MIN = 15  # °C

# ================= WIFI =================
def connect_wifi():
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    wlan.connect("Wokwi-GUEST", "")
    while not wlan.isconnected():
        print(".", end="")
        sleep(0.5)
    print("\nWiFi Connected!")

# ================= MQTT CALLBACK =================
def sub_cb(topic, msg):
    message = msg.decode()
    print("Message from SCADA:", message)
    if message == "OFF":
        Buzzer.duty(0)
    elif message == "ON":
        Buzzer.freq(1000)
        Buzzer.duty(512)

# ================= MQTT CONNECT =================
def connect_mqtt():
    client = MQTTClient(MQTT_CLIENT_ID, MQTT_BROKER, port=1883)
    client.set_callback(sub_cb)
    client.connect()
    client.subscribe(MQTT_CONTROL)
    client.publish(MQTT_STATUS, "online", retain=True)
    print("MQTT Connected & Subscribed!")
    return client

# ================= START =================
connect_wifi()
client = connect_mqtt()

# ================= VARIABLES =================
Number_of_people = 0
Total_student = 10
last_motion_time = 0
motion_delay = 3000  # debounce 3 seconds

# ================= MAIN LOOP =================
while True:
    client.check_msg()
    
    # -------- DHT READ --------
    try:
        dht_sensor.measure()
        temp = dht_sensor.temperature()
        hum  = dht_sensor.humidity()
    except:
        temp, hum = None, None

    # -------- TEMPERATURE ALERT --------
    if temp is not None and (temp > TEMP_MAX or temp < TEMP_MIN):
        alert = 1
        Red_led.on()
        Green_led.off()
        Buzzer.freq(1000)
        Buzzer.duty(512)
    else:
        alert = 0
        Red_led.off()
        Green_led.on()
        Buzzer.duty(0)

    # -------- PRESENCE DETECTION (room_status always Empty/Occupied) --------
    motion_status = PIR_sensor.value()
    current_time = ticks_ms()
    if motion_status == 0 and (current_time - last_motion_time) > motion_delay:
        Number_of_people = min(Number_of_people + 1, Total_student)
        last_motion_time = current_time

    if Number_of_people > 0:
        status_msg = "Occupied"
    else:
        status_msg = "Empty"
    
    absent = Total_student - Number_of_people

    # -------- MQTT PAYLOAD --------
    payload = ujson.dumps({
        "temperature": temp,
        "humidity": hum,
        "presence": 1 if Number_of_people > 0 else 0,
        "students_count": Number_of_people,
        "absent_count": absent,
        "room_status": status_msg,
        "alert": alert
    })

    try:
        client.publish(MQTT_TOPIC, payload)
        print("Data sent to SCADA:", payload)
    except:
        print("MQTT Reconnecting...")
        client = connect_mqtt()
    
    sleep(5)