#include "DHT.h"

#define DHTPIN 4        
#define DHTTYPE DHT11   
#define TRIG1 5         
#define ECHO1 18        
#define TRIG2 19        
#define ECHO2 21        
#define MQ2_AOUT 34     
#define MQ2_DOUT 35     
#define BUZZER 32       // Updated buzzer pin
#define LED 33          // Updated LED pin

DHT dht(DHTPIN, DHTTYPE);

void setup() {
    Serial.begin(115200);
    pinMode(TRIG1, OUTPUT);
    pinMode(ECHO1, INPUT);
    pinMode(TRIG2, OUTPUT);
    pinMode(ECHO2, INPUT);
    pinMode(MQ2_AOUT, INPUT);
    pinMode(MQ2_DOUT, INPUT);
    pinMode(BUZZER, OUTPUT);
    pinMode(LED, OUTPUT);

    delay(2000); // Ensure DHT Sensor is ready
    dht.begin();
}

float getDistance(int trigPin, int echoPin) {
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    
    long duration = pulseIn(echoPin, HIGH, 30000); // Timeout after 30ms
    if (duration == 0) return -1; // Return -1 if no pulse detected

    float distance = duration * 0.034 / 2;
    return distance;
}

void loop() {
    float temperature = dht.readTemperature();
    float humidity = dht.readHumidity();
    float distance1 = getDistance(TRIG1, ECHO1);
    float distance2 = getDistance(TRIG2, ECHO2);
    int gasValue = analogRead(MQ2_AOUT);
    
    Serial.print("Temp: "); Serial.print(temperature); Serial.print("°C ");
    Serial.print("Humidity: "); Serial.print(humidity); Serial.print("% ");
    Serial.print("Dist1: "); Serial.print(distance1); Serial.print("cm ");
    Serial.print("Dist2: "); Serial.print(distance2); Serial.print("cm ");
    Serial.print("Gas: "); Serial.println(gasValue);

    // **Thresholds for Buzzer & LED**
    if (temperature > 40 || humidity < 20 || distance1 > 50 || distance2 > 50 || gasValue > 3000) {
        digitalWrite(LED, HIGH);
        Serial.println("⚠ WARNING: Unsafe Conditions! ⚠");
        Serial.println("Buzzer ON 🚨");

        tone(BUZZER, 1000);  // 1kHz alarm

        delay(2000);  // Keep buzzer ON for 2 sec
        noTone(BUZZER);  // Stop buzzer
    } else {
        digitalWrite(LED, LOW);
        digitalWrite(BUZZER, LOW);
    }

    delay(2000);  // Wait before next update
}