#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <RTClib.h>
#include <SPI.h>
#include <SD.h>

// --- KONFIGURASI PIN ---
#define PIN_CS_SD    4   // Chip Select SD Card
#define PIN_TOMBOL   2   // Tombol (Simulasi RFID)
#define PIN_BUZZER   4   // Buzzer (Saya set ke Pin 4 sesuai request terakhir)

// Inisialisasi Komponen
LiquidCrystal_I2C lcd(0x27, 16, 2);
RTC_DS1307 rtc;
File myFile;

void setup() {
  Serial.begin(9600);
  
  // Setup Pin
  pinMode(PIN_TOMBOL, INPUT_PULLUP);
  pinMode(PIN_BUZZER, OUTPUT);

  // 1. Setup LCD
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0,0); lcd.print("Booting System...");
  delay(500);

  // 2. Setup RTC (Jam)
  if (!rtc.begin()) {
    lcd.setCursor(0,1); lcd.print("RTC Error!");
    while(1);
  }
  if (!rtc.isrunning()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }

  // 3. Setup SD Card
  Serial.print("Cek SD Card...");
  if (!SD.begin(PIN_CS_SD)) {
    lcd.setCursor(0,1); lcd.print("SD Card Gagal!");
    return;
  }
  Serial.println("OK!");

  // Buat Header File Excel
  myFile = SD.open("absen.csv", FILE_WRITE);
  if (myFile) {
    if (myFile.size() == 0) {
      myFile.println("TANGGAL,JAM,NAMA,STATUS");
    }
    myFile.close();
  }

  tampilanAwal();
}

void loop() {
  // --- LOGIKA BARU (LANGSUNG RESPON) ---
  
  // Cek apakah tombol ditekan (LOW)
  if (digitalRead(PIN_TOMBOL) == LOW) {
    
    // 1. LANGSUNG BUNYI & EKSEKUSI (Tanpa Delay Pengecekan)
    tone(PIN_BUZZER, 2000); 
    
    // 2. Data Simulasi
    String nama = "Ust. Budi"; 
    DateTime now = rtc.now();
    
    // 3. Tampilkan di LCD
    lcd.clear();
    lcd.setCursor(0,0); lcd.print("Ahlan wa Sahlan");
    lcd.setCursor(0,1); lcd.print(nama);
    
    // 4. Simpan ke SD Card
    simpanData(now, nama);
    
    delay(100);             // Durasi bunyi buzzer
    noTone(PIN_BUZZER);     // Matikan buzzer
    
    // 5. Tahan layar sebentar (biar terbaca)
    delay(1500);
    
    // 6. Balik ke menu awal
    tampilanAwal();
    
    // 7. KUNCI TOMBOL (Agar tidak absen berulang-ulang kalau ditahan)
    // Selama tombol masih ditekan, program berhenti di baris ini
    while(digitalRead(PIN_TOMBOL) == LOW) {
      delay(10); 
    }
  }
}

void tampilanAwal() {
  lcd.clear();
  lcd.setCursor(0,0); lcd.print("SIAP ABSENSI");
  lcd.setCursor(0,1); lcd.print("Tempel Kartu...");
}

void simpanData(DateTime tgl, String nm) {
  myFile = SD.open("absen.csv", FILE_WRITE);
  if (myFile) {
    myFile.print(tgl.year()); myFile.print("/");
    myFile.print(tgl.month()); myFile.print("/");
    myFile.print(tgl.day()); myFile.print(",");
    
    myFile.print(tgl.hour()); myFile.print(":");
    myFile.print(tgl.minute()); myFile.print(":");
    myFile.print(tgl.second()); myFile.print(",");
    
    myFile.print(nm); myFile.println(",HADIR");
    myFile.close();
    Serial.println("Sukses: " + nm);
  } else {
    Serial.println("Gagal SD Card!");
  }
}