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

LiquidCrystal_I2C lcd(0x27, 16, 2); // Change 0x27 to 0x3F if needed

#define IR_SENSOR 2
#define SET_BTN   3
#define UP_BTN    4
#define DOWN_BTN  5
#define BUZZER    6

int count = 0;
int preset = 10; 
bool lastIRState = HIGH;
bool setMode = false;
unsigned long lastDebounce = 0;

void setup() {
  pinMode(IR_SENSOR, INPUT);
  pinMode(SET_BTN, INPUT_PULLUP);
  pinMode(UP_BTN, INPUT_PULLUP);
  pinMode(DOWN_BTN, INPUT_PULLUP);
  pinMode(BUZZER, OUTPUT);
  
  lcd.init();
  lcd.backlight();
  
  // Read from EEPROM
  EEPROM.get(0, count);
  EEPROM.get(10, preset);
  if (preset == 0xFFFF) preset = 10; // First time default
  if (count == 0xFFFF) count = 0;
  
  updateDisplay();
}

void loop() {
  // SET button - toggle set mode or long press to reset count
  if (digitalRead(SET_BTN) == LOW && millis() - lastDebounce > 200) {
    lastDebounce = millis();
    if (!setMode) {
      setMode = true;
    } else {
      setMode = false;
      EEPROM.put(10, preset); // Save preset
    }
    updateDisplay();
    while(digitalRead(SET_BTN) == LOW); // Wait release
  }
  
  // Long press SET to reset count
  if (digitalRead(SET_BTN) == LOW) {
    delay(2000);
    if (digitalRead(SET_BTN) == LOW) {
      count = 0;
      EEPROM.put(0, count);
      digitalWrite(BUZZER, LOW);
      updateDisplay();
      while(digitalRead(SET_BTN) == LOW);
    }
  }

  // UP/DOWN only work in setMode
  if (setMode) {
    if (digitalRead(UP_BTN) == LOW && millis() - lastDebounce > 200) {
      preset++;
      lastDebounce = millis();
      updateDisplay();
    }
    if (digitalRead(DOWN_BTN) == LOW && millis() - lastDebounce > 200) {
      preset = max(1, preset - 1); // Min preset = 1
      lastDebounce = millis();
      updateDisplay();
    }
  } 
  else {
    // Normal counting mode
    bool irState = digitalRead(IR_SENSOR);
    if (irState == LOW && lastIRState == HIGH) { // Object detected
      delay(50); // debounce
      if (digitalRead(IR_SENSOR) == LOW) {
        count++;
        EEPROM.put(0, count); // Save to EEPROM each count
        updateDisplay();
        
        if (count >= preset) {
          digitalWrite(BUZZER, HIGH); // Preset reached
        }
      }
    }
    lastIRState = irState;
  }
}

void updateDisplay() {
  lcd.clear();
  if (setMode) {
    lcd.setCursor(0,0);
    lcd.print("SET PRESET MODE");
    lcd.setCursor(0,1);
    lcd.print("Preset: ");
    lcd.print(preset);
  } else {
    lcd.setCursor(0,0);
    lcd.print("Count: ");
    lcd.print(count);
    lcd.setCursor(0,1);
    lcd.print("Preset: ");
    lcd.print(preset);
    if (count >= preset) {
      lcd.setCursor(13,0);
      lcd.print("ALM");
    }
  }
}