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

// Definisi pin
#define TRIGGER_PIN 2  // Pin trigger sensor ultrasonik
#define ECHO_PIN 3     // Pin echo sensor ultrasonik
#define GREEN_LED 4   // LED hijau
#define YELLOW_LED 5  // LED kuning
#define RED_LED 6     // LED merah
#define BUZZER 7      // Buzzer
#define START_BUTTON 8 // Tombol start

// Inisialisasi LCD (sesuaikan alamat I2C jika berbeda)
LiquidCrystal_I2C lcd(0x27, 20, 4);

// Variabel global
float waterLevel = 0.0;
bool isRunning = false;
unsigned long previousMillis = 0; // Untuk mengatur interval buzzer
bool buzzerState = false;       // Status buzzer

void setup() {
  // Inisialisasi pin
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(GREEN_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(RED_LED, OUTPUT);
  pinMode(BUZZER, OUTPUT);
  pinMode(START_BUTTON, INPUT_PULLUP);

  // Inisialisasi I2C dengan pin spesifik
  Wire.setSDA(16);  // SDA di GPIO 16
  Wire.setSCL(17);  // SCL di GPIO 17

  // Inisialisasi LCD
  lcd.init();
  lcd.backlight();

  // Inisialisasi Serial untuk debug
  Serial.begin(9600);

  // Tampilan awal
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Detektor Banjir");
  lcd.setCursor(0, 1);
  lcd.print("Tekan Tombol Mulai");

  // Matikan semua LED dan buzzer
  digitalWrite(GREEN_LED, LOW);
  digitalWrite(YELLOW_LED, LOW);
  digitalWrite(RED_LED, LOW);
  digitalWrite(BUZZER, LOW);
}

void loop() {
  // Cek tombol start
  if (digitalRead(START_BUTTON) == LOW) {
    delay(50); // Debounce
    isRunning = !isRunning;

    // Reset semua indikator
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(YELLOW_LED, LOW);
    digitalWrite(RED_LED, LOW);
    digitalWrite(BUZZER, LOW);
    noTone(BUZZER);

    // Tampilan saat dimulai
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Sistem Aktif");
    lcd.setCursor(0, 1);
    lcd.print("Mengukur Banjir...");

    delay(1000);
  }

  if (isRunning) {
    // Ukur ketinggian air
    waterLevel = measureWaterLevel();

    // Debugging: tampilkan nilai waterLevel
    Serial.print("Water Level: ");
    Serial.println(waterLevel);

    // Update LCD
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Level Air: ");
    lcd.print(waterLevel);
    lcd.print(" m");

    // Logika indikator banjir
    if (waterLevel >= 0 && waterLevel < 1) {
      digitalWrite(GREEN_LED, HIGH);
      digitalWrite(YELLOW_LED, LOW);
      digitalWrite(RED_LED, LOW);
      digitalWrite(BUZZER, LOW);
      noTone(BUZZER);
      lcd.setCursor(0, 1);
      lcd.print("Status: Aman");
    }
    else if (waterLevel >= 1 && waterLevel < 2) {
      digitalWrite(GREEN_LED, LOW);
      digitalWrite(YELLOW_LED, HIGH);
      digitalWrite(RED_LED, LOW);
      digitalWrite(BUZZER, LOW);
      noTone(BUZZER);
      lcd.setCursor(0, 1);
      lcd.print("Status: Waspada");
    }
    else { // Jika waterLevel >= 2 (Bahaya)
      digitalWrite(GREEN_LED, LOW);
      digitalWrite(YELLOW_LED, LOW);
      digitalWrite(RED_LED, HIGH);
      lcd.setCursor(0, 1);
      lcd.print("Status: Bahaya");

      // Aktifkan buzzer dengan pola tut-tut
      unsigned long currentMillis = millis();
      if (currentMillis - previousMillis >= 500) { // Interval 500 ms
        previousMillis = currentMillis;
        buzzerState = !buzzerState;
        if (buzzerState) {
          tone(BUZZER, 1000); // Frekuensi 1000 Hz
        } else {
          noTone(BUZZER);
        }
      }
      Serial.println("BAHAYA - Buzzer ON");
    }

    delay(1000); // Tunda 1 detik antara pembacaan
  }
}

float measureWaterLevel() {
  // Fungsi untuk mengukur ketinggian air menggunakan sensor ultrasonik
  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER_PIN, LOW);

  // Baca durasi pantulan
  long duration = pulseIn(ECHO_PIN, HIGH);

  // Debugging: tampilkan durasi
  Serial.print("Duration: ");
  Serial.println(duration);

  // Hitung jarak (dalam meter)
  float distance = (duration * 0.034 / 2) / 100; // Konversi ke meter

  // Jika durasi terlalu besar atau kecil, anggap level 0 (menangani error)
  if (duration <= 0 || duration > 30000) {
    distance = 0;
  }

  // Pastikan hasil dalam rentang 0 hingga 3.7 meter
  if (distance < 0) {
    distance = 0;
  } else if (distance > 3.7) {
    distance = 3.7;
  }

  return distance;
}