import network
import time
import machine
import math
from machine import Pin, ADC
from umqtt.simple import MQTTClient

# --- Configuration ---
SSID = "Wokwi-GUEST"
PASSWORD = ""
MQTT_BROKER = "broker.hivemq.com"

TOPIC_TEMP = "esp32/temp"
TOPIC_RELAY_CMD = "esp32/relay_cmd"
TOPIC_THRESHOLD = "esp32/set_threshold"

# --- Hardware Setup ---
relay = Pin(21, Pin.OUT)
adc = ADC(Pin(34))
adc.width(ADC.WIDTH_10BIT)
adc.atten(ADC.ATTN_11DB)

# --- Variables ---
mode = "manual"  # can be "manual" or "auto"
threshold = 30   # default temperature threshold in °C

# --- WiFi Connection ---
def connect_wifi():
    print("Connecting to Wi-Fi...")
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    wlan.connect(SSID, PASSWORD)
    while not wlan.isconnected():
        time.sleep(0.5)
    print("Connected to Wi-Fi:", wlan.ifconfig())

# --- MQTT Callback ---
def mqtt_callback(topic, msg):
    global mode, threshold
    topic = topic.decode()
    msg = msg.decode()
    
    print("Received:", topic, msg)
    
    if topic == TOPIC_RELAY_CMD:
        mode = "manual"
        if msg == "on":
            relay.value(1)
            print("Relay turned ON (manual)")
        elif msg == "off":
            relay.value(0)
            print("Relay turned OFF (manual)")

    elif topic == TOPIC_THRESHOLD:
        mode = "auto"
        try:
            threshold = float(msg)
            print("Threshold updated to:", threshold)
        except:
            print("Invalid threshold value!")

# --- Temperature Reading ---
def read_temperature():
    BETA = 3950
    value = adc.read()
    if value == 0:
        return 0
    celsius = 1 / (math.log(1 / (1023. / value - 1)) / BETA + 1.0 / 298.15) - 273.15
    return round(celsius, 2)

# --- Main Program ---
def main():
    connect_wifi()
    client = MQTTClient("esp32_client", MQTT_BROKER)
    client.set_callback(mqtt_callback)
    client.connect()
    print("MQTT Connected!")

    client.subscribe(TOPIC_RELAY_CMD)
    client.subscribe(TOPIC_THRESHOLD)

    while True:
        temp = read_temperature()
        print("Temperature:", temp, "°C")
        
        # Publish temperature
        client.publish(TOPIC_TEMP, str(temp))
        
        # Auto mode logic
        if mode == "auto":
            if temp > threshold:
                relay.value(1)
                print("Relay ON (auto)")
            else:
                relay.value(0)
                print("Relay OFF (auto)")

        # Check MQTT messages
        client.check_msg()

        time.sleep(2)

# --- Run ---
main()