#include <LiquidCrystal_I2C.h>

/* ================= PIN CONFIG ================= */

#define TRIG_PIN 5
#define ECHO_PIN 18
#define SSR_PIN 23

// A4988 DRIVER
#define STEP_PIN 19
#define DIR_PIN 21
#define EN_PIN 22      // Optional tapi disarankan

#define BUZZER_LED 2

/* ================= LCD ================= */

LiquidCrystal_I2C lcd(0x27, 16, 2);

/* ================= GLOBAL VAR ================= */

long duration;
float distance;
float setPoint = 0;

unsigned long startTime;

/* ================= ULTRASONIC ================= */

float readUltrasonic() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  duration = pulseIn(ECHO_PIN, HIGH, 30000); // timeout biar ga hang

  if (duration == 0) return 0; // jika gagal baca

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

/* ================= STEPPER CONTROL ================= */

void stepMotor(int steps, bool dir, int delayMicros) {

  digitalWrite(DIR_PIN, dir);

  for (int i = 0; i < steps; i++) {
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(delayMicros);
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(delayMicros);
  }
}

/* ================= FUZZY LOGIC ================= */

void fuzzyLogic(float jarak) {

  if (jarak >= 15) {
    setPoint = 40;
    stepMotor(200, HIGH, 600);   // Pelan
  } 
  else if (jarak > 5 && jarak < 15) {
    setPoint = 60;
    stepMotor(200, HIGH, 1500);    // Cepat
  } 
  else if (jarak <= 5 && jarak > 0) {
    setPoint = 75;
    stepMotor(200, HIGH, 1500);    // Cepat
  }
}

/* ================= SETUP ================= */

void setup() {

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(SSR_PIN, OUTPUT);

  pinMode(STEP_PIN, OUTPUT);
  pinMode(DIR_PIN, OUTPUT);
  pinMode(EN_PIN, OUTPUT);

  pinMode(BUZZER_LED, OUTPUT);

  digitalWrite(EN_PIN, LOW);     // Enable A4988 (LOW = aktif)
  digitalWrite(SSR_PIN, HIGH);   // Heater ON

  lcd.init();
  lcd.backlight();

  startTime = millis();
}

/* ================= LOOP ================= */

void loop() {

  unsigned long currentTime = millis();

  // AUTO OFF 30 MENIT
  if (currentTime - startTime >= 1800000) {

    digitalWrite(SSR_PIN, LOW);     // Heater OFF
    digitalWrite(BUZZER_LED, HIGH); // Alarm ON

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Proses Selesai");
    lcd.setCursor(0, 1);
    lcd.print("Heater OFF");

    while (true); // Stop sistem
  }

  distance = readUltrasonic();

  fuzzyLogic(distance);

  lcd.setCursor(0, 0);
  lcd.print("Jarak: ");
  lcd.print(distance, 1);
  lcd.print(" cm   ");

  lcd.setCursor(0, 1);
  lcd.print("SP Suhu: ");
  lcd.print(setPoint);
  lcd.print(" C   ");

  delay(200);
}