#define WIFI_SSID "Wokwi-GUEST"
#define WIFI_PASSWORD ""
#define MQTT_SERVER "broker.hivemq.com"
#define MQTT_PORT 1883
#define MQTT_TOPIC "testing"
#define DHT_PIN 15        
#define LED_PIN 32       

#include "DHTesp.h"
#include <LiquidCrystal_I2C.h>
#include <WiFi.h>
#include <PubSubClient.h> // MQTT library
#include <ArduinoJson.h>

DHTesp dhtSensor;        
LiquidCrystal_I2C lcd(0x27, 20, 4); 
WiFiClient espClient;
PubSubClient client(espClient);

float lastTemp = -100.0; 
float lastHumid = -100.0;
const char* username = "test";
const char* password = "";

void mqttCallback(char* topic, byte* payload, unsigned int length) {
 
  char msg[50];
  memcpy(msg, payload, length);
  Serial.println(msg);
  msg[length] = '\0';  
  JsonDocument doc;
  deserializeJson(doc, msg);
 
  Serial.println("Temp and humid");
  int temp = doc["Temp"];
  int humid = doc["Humid"];
  Serial.println(temp);
  Serial.println(humid);
 
  if (temp < 30.0) {
    digitalWrite(LED_PIN, HIGH);  
    Serial.println("LED turned ON (Temperature < 30°C)");
  } else {
    digitalWrite(LED_PIN, LOW); 
    Serial.println("LED turned OFF (Temperature >= 30°C)");
  }

}

void setup() {
  Serial.begin(9600);
  Serial.println("ESP32 collecting sensor data");
 
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD, 7);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi!");
 
  client.setServer(MQTT_SERVER, MQTT_PORT);
  client.setCallback(mqttCallback);
  reconnect();
 
  dhtSensor.setup(DHT_PIN, DHTesp::DHT22);
 
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);
 
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("ESP32 collecting data...");
  delay(500);
}

void reconnect() {

  while (!client.connected()) {
    Serial.println("Connecting to MQTT...");
    if (client.connect("a4b40540-2fab-4da8-a1f3-6f3d04287205", username, password)) {
      Serial.println("Connected to MQTT broker");
      
      client.subscribe(MQTT_TOPIC);
    } else {
      Serial.print("Failed to connect, retrying in 5 seconds...");
      delay(500);
    }
  }
}

void loop() {
delay(1000);
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
client.setCallback(mqttCallback);

  TempAndHumidity data = dhtSensor.getTempAndHumidity();
  float temp = data.temperature;
  float humid = data.humidity;


  if (isnan(temp) || isnan(humid)) {
    Serial.println("Failed to read from DHT sensor!");
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Sensor error!");
    delay(200);
    return;
  }


  String stemp = String(temp, 1) + "C";
  String shumid = String(humid, 1) + "%";


  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temp: " + stemp);
  lcd.setCursor(0, 1);
  lcd.print("Humidity: " + shumid);

}