#include <LiquidCrystal.h>
#include <Keypad.h>
#include <HX711.h>
#include <Servo.h>

// =====================================
// 1. LCD 16x2 STANDAR (16 PIN)
// =====================================
// Urutan: RS, E, D4, D5, D6, D7
LiquidCrystal lcd(12, 11, 13, A2, A3, A4);

// =====================================
// 2. HX711 + LOAD CELL 5 KG
// =====================================
const byte HX_DOUT = A1;
const byte HX_SCK  = A0;

HX711 scale;

// GANTI setelah kalibrasi sensor.
// Nilai ini hanya nilai awal, belum tentu cocok.
float CAL_FACTOR = -7050.0;

// =====================================
// 3. SERVO SG90
// =====================================
const byte SERVO_PIN = 10;

const int SERVO_CLOSED = 0;
const int SERVO_OPEN   = 90;

Servo servo;

// =====================================
// 4. KEYPAD 4x4
// =====================================
const byte ROWS = 4;
const byte COLS = 4;

char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte rowPins[ROWS] = {9, 8, 7, 6};
byte colPins[COLS] = {5, 4, 3, 2};

Keypad keypad = Keypad(
  makeKeymap(keys),
  rowPins,
  colPins,
  ROWS,
  COLS
);

// =====================================
// 5. PENGATURAN TAKARAN
// =====================================
float targetWeight = 0;
float currentWeight = 0;

bool targetSelected = false;
bool dispensing = false;

// Nilai awal kompensasi aliran
const float STOP_MARGIN_G = 5.0;

// Batas waktu maksimum
const unsigned long MAX_DISPENSE_MS = 30000UL;

// =====================================
// 6. FUNGSI TAMPILAN LCD
// =====================================
void showMenu() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Pilih takaran:");
  lcd.setCursor(0, 1);
  lcd.print("1:100 2:250 3:500");
}

void showTarget() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Target dipilih:");
  lcd.setCursor(0, 1);
  lcd.print(targetWeight, 0);
  lcd.print(" g #=Mulai");
}

void showWeight() {
  lcd.setCursor(0, 0);
  lcd.print("Berat:");
  lcd.print(currentWeight, 1);
  lcd.print("g     ");

  lcd.setCursor(0, 1);
  lcd.print("Target:");
  lcd.print(targetWeight, 0);
  lcd.print("g     ");
}

void closeServo() {
  servo.write(SERVO_CLOSED);
}

void resetSystem() {
  closeServo();

  targetWeight = 0;
  targetSelected = false;
  dispensing = false;

  showMenu();
}

// =====================================
// 7. PEMILIHAN PRESET
// =====================================
void selectPreset(char key) {
  switch (key) {
    case '1':
      targetWeight = 100;
      break;

    case '2':
      targetWeight = 250;
      break;

    case '3':
      targetWeight = 500;
      break;

    case '4':
      targetWeight = 1000;
      break;

    default:
      return;
  }

  targetSelected = true;
  showTarget();

  Serial.print("Target dipilih: ");
  Serial.print(targetWeight);
  Serial.println(" gram");
}

// =====================================
// 8. PROSES DISPENSING
// =====================================
void dispense() {
  if (!targetSelected || targetWeight <= 0) {
    lcd.clear();
    lcd.print("Pilih preset");
    delay(1200);
    showMenu();
    return;
  }

  if (!scale.is_ready()) {
    closeServo();
    lcd.clear();
    lcd.print("ERROR HX711");
    lcd.setCursor(0, 1);
    lcd.print("Cek koneksi");
    delay(2000);
    resetSystem();
    return;
  }

  // Berat harus nol sebelum mulai.
  currentWeight = scale.get_units(5);

  if (currentWeight > 5.0) {
    lcd.clear();
    lcd.print("Wadah belum");
    lcd.setCursor(0, 1);
    lcd.print("kosong / tare");
    delay(1800);
    resetSystem();
    return;
  }

  dispensing = true;

  unsigned long startTime = millis();

  lcd.clear();
  lcd.print("Mengeluarkan...");
  lcd.setCursor(0, 1);
  lcd.print("Tekan * = Batal");

  // Buka pintu dispenser
  servo.write(SERVO_OPEN);

  while (dispensing) {
    char key = keypad.getKey();

    // Pembatalan
    if (key == '*') {
      closeServo();
      lcd.clear();
      lcd.print("Proses dibatal");
      lcd.setCursor(0, 1);
      lcd.print("Servo tertutup");
      delay(1500);

      resetSystem();
      return;
    }

    // Timeout
    if (millis() - startTime >= MAX_DISPENSE_MS) {
      closeServo();

      lcd.clear();
      lcd.print("TIMEOUT!");
      lcd.setCursor(0, 1);
      lcd.print("Cek mekanisme");

      Serial.println("ERROR: Timeout dispensing");

      delay(2000);
      resetSystem();
      return;
    }

    // Sensor harus tetap merespons
    if (!scale.is_ready()) {
      closeServo();

      lcd.clear();
      lcd.print("ERROR HX711");
      lcd.setCursor(0, 1);
      lcd.print("Servo ditutup");

      delay(2000);
      resetSystem();
      return;
    }

    currentWeight = scale.get_units(3);

    showWeight();

    Serial.print("Berat: ");
    Serial.print(currentWeight, 1);
    Serial.println(" g");

    // Target dikurangi margin kompensasi
    if (currentWeight >= targetWeight - STOP_MARGIN_G) {
      closeServo();
      dispensing = false;
    }

    delay(100);
  }

  // Tunggu berat stabil
  delay(1000);

  if (scale.is_ready()) {
    currentWeight = scale.get_units(10);
  }

  lcd.clear();
  lcd.print("Selesai!");
  lcd.setCursor(0, 1);
  lcd.print("Hasil:");
  lcd.print(currentWeight, 1);
  lcd.print("g");

  Serial.print("Target: ");
  Serial.print(targetWeight);
  Serial.print(" g | Hasil: ");
  Serial.print(currentWeight, 1);
  Serial.println(" g");

  delay(3000);

  resetSystem();
}

// =====================================
// 9. SETUP
// =====================================
void setup() {
  Serial.begin(9600);

  // LCD standar, bukan I2C
  lcd.begin(16, 2);
  lcd.clear();

  // Servo langsung ke posisi tertutup
  servo.attach(SERVO_PIN);
  closeServo();

  lcd.print("Smart Dispenser");
  lcd.setCursor(0, 1);
  lcd.print("Inisialisasi...");

  // Inisialisasi HX711
  scale.begin(HX_DOUT, HX_SCK);
  scale.set_scale(CAL_FACTOR);

  delay(1000);

  if (!scale.is_ready()) {
    lcd.clear();
    lcd.print("HX711 ERROR");
    lcd.setCursor(0, 1);
    lcd.print("Cek wiring");

    Serial.println("HX711 tidak siap.");

    // Jangan menjalankan dispensing
    while (true) {
      closeServo();
      delay(500);
    }
  }

  scale.tare(10);

  lcd.clear();
  lcd.print("Sistem siap!");
  delay(1500);

  showMenu();

  Serial.println("Smart Dispenser siap.");
}

// =====================================
// 10. LOOP UTAMA
// =====================================
void loop() {
  char key = keypad.getKey();

  if (key == NO_KEY) {
    return;
  }

  Serial.print("Tombol ditekan: ");
  Serial.println(key);

  if (key == '*') {
    closeServo();
    resetSystem();
    return;
  }

  if (key >= '1' && key <= '4') {
    selectPreset(key);
    return;
  }

  if (key == '#') {
    dispense();
  }
}