#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include "DHT.h"

// DHT Sensor
#define pinDHT 8
#define typeDHT DHT22
DHT dht(pinDHT, typeDHT);

// LCD
LiquidCrystal_I2C lcd(0x27, 16, 2); // Default address 0x27 for 16x2 LCD

// Pin definitions
int sensor_gas = A0;  
int redLED = 4;  
int greenLED = 3; 
int buzzer = 5;  
int buttonOFF = 9;
int buttonON = 10;
int relayPin = 7;

// Thresholds
int sensorThreshold = 400; 
float tempThreshold = 40.0;

bool alarmMuted = false; // Status untuk alarm
bool systemOn = false; // Status untuk sistem
unsigned long previousMillis = 0; // Store last time tone was played
const long interval = 300; // Interval between tones in milliseconds

void setup() {
  // Setup pinMode
  pinMode(sensor_gas, INPUT);
  pinMode(redLED, OUTPUT);
  pinMode(greenLED, OUTPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(buttonOFF, INPUT_PULLUP);
  pinMode(buttonON, INPUT_PULLUP);
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, HIGH); // Pastikan relay dimatikan saat mulai

  // Setup LCD
  lcd.begin(16, 2);
  lcd.clear();
  lcd.backlight();

  // Setup DHT
  dht.begin();

  // Initialize Serial Monitor
  Serial.begin(9600);
}

void loop() {
  // Check button states
  if (digitalRead(buttonON) == LOW) {
    systemOn = true;
    delay(50); // Debounce delay
  }
  
  if (digitalRead(buttonOFF) == LOW) {
    systemOn = false;
    delay(50); // Debounce delay
  }

  if (systemOn) {
    int analogSensor = analogRead(sensor_gas);
    float h = dht.readHumidity();
    float t = dht.readTemperature();
    unsigned long currentMillis = millis();

    // Display temperature and humidity on Serial Monitor
    Serial.print("Temperature: ");
    Serial.print(t);
    Serial.print(" *C, Humidity: ");
    Serial.print(h);
    Serial.println(" %");

    // High temperature notification
    if (t > tempThreshold) {
      if(analogSensor > sensorThreshold) {
        lcd.setCursor(0, 0);
        lcd.print("SUHU ");
        lcd.print(t);
        lcd.print(" *C      ");
        lcd.setCursor(0, 1);
        lcd.print("GAS BOCOR!     ");
        digitalWrite(greenLED, LOW);
        digitalWrite(redLED, HIGH);
        digitalWrite(relayPin, LOW); // Mematikan relay (memutus listrik)
        
        // If alarm is not muted, alternate between two tones
        if (!alarmMuted && currentMillis - previousMillis >= interval) {
          previousMillis = currentMillis;
          tone(buzzer, (currentMillis / interval) % 2 == 0 ? 2000 : 2500); // Alternate between 2000Hz and 2500Hz
        } else {
          noTone(buzzer);
        }
      } else {
        lcd.setCursor(0, 0);
        lcd.print("SUHU TINGGI!    ");
        lcd.setCursor(0, 1);
        lcd.print(t);
        lcd.print(" *C       ");
        noTone(buzzer);
        digitalWrite(relayPin, HIGH); // Menghidupkan kembali relay (menyambung listrik)
      }
    } else {
      // Check for gas leakage
      if (analogSensor > sensorThreshold) {
        lcd.setCursor(0, 0);
        lcd.print("Kondisi Ruangan:");
        lcd.setCursor(0, 1);
        lcd.print("GAS BOCOR!      ");
        digitalWrite(redLED, LOW);
        digitalWrite(greenLED, LOW);
        digitalWrite(relayPin, HIGH); // Menghidupkan kembali relay (menyambung listrik)
        delay(500);
        digitalWrite(redLED, HIGH);
        
        // If alarm is not muted, alternate between two tones
        if (!alarmMuted && currentMillis - previousMillis >= interval) {
          previousMillis = currentMillis;
          tone(buzzer, (currentMillis / interval) % 2 == 0 ? 1000 : 1500); // Alternate between 1000Hz and 1500Hz
        } else {
          noTone(buzzer);
        }
      } else {
        lcd.setCursor(0, 0);
        lcd.print("Kondisi Ruangan:");
        lcd.setCursor(0, 1);
        lcd.print("Gas aman.     ");
        digitalWrite(redLED, LOW);
        digitalWrite(greenLED, HIGH);
        noTone(buzzer);
        alarmMuted = false;
        digitalWrite(relayPin, HIGH); // Menghidupkan kembali relay (menyambung listrik)
      }
    }
  } else {
    // System is off, turn off everything
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Sistem Mati");
    digitalWrite(redLED, LOW);
    digitalWrite(greenLED, LOW);
    noTone(buzzer);
    digitalWrite(relayPin, HIGH); // Memastikan relay tetap mati
  }

  delay(1000); // 1 second delay for the next reading
}