#include <Wire.h>
#include <SPI.h>
#include <MFRC522.h>
#include <LiquidCrystal_I2C.h>

// -------- RFID --------
#define SS_PIN 10
#define RST_PIN 9
MFRC522 rfid(SS_PIN, RST_PIN);

// -------- LCD --------
LiquidCrystal_I2C lcd(0x27, 16, 2);

// -------- Button --------
int buttonPin = 2;
bool machineRunning = false;

// -------- Timing --------
unsigned long startTime = 0;
unsigned long duration = 0;
unsigned long lastPressTime = 0;

// -------- Worker --------
String workerName = "None";

// -------- SETTINGS --------
const int OFF_DELAY = 1000; // 1 sec delay for stability

void setup() {
  Serial.begin(9600);

  SPI.begin();
  rfid.PCD_Init();

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

  pinMode(buttonPin, INPUT_PULLUP);

  lcd.print("System Ready");
  delay(2000);
  lcd.clear();
}

void loop() {

  // -------- BUTTON LOGIC --------
  int buttonState = digitalRead(buttonPin);

  // Pressed (LOW)
  if (buttonState == LOW) {
    lastPressTime = millis();

    if (!machineRunning) {
      machineRunning = true;
      startTime = millis();
    }
  }

  // Released → turn OFF after delay
  if (machineRunning && (millis() - lastPressTime > OFF_DELAY)) {
    machineRunning = false;
    duration = (millis() - startTime) / 1000;
  }

  // -------- RFID --------
  if (rfid.PICC_IsNewCardPresent() && rfid.PICC_ReadCardSerial()) {

    String uid = "";

    for (byte i = 0; i < rfid.uid.size; i++) {
      uid += String(rfid.uid.uidByte[i], HEX);
    }

    uid.toLowerCase();

    if (uid == "a35f2c91") {
      workerName = "Ravi";
    }
    else if (uid == "b4129af3") {
      workerName = "Vinay";
    }
    else {
      workerName = "Ashwin";
    }

    rfid.PICC_HaltA();
  }

  // -------- DISPLAY --------
  lcd.clear();

  unsigned long currentDuration;

  if (machineRunning) {
    currentDuration = (millis() - startTime) / 1000;
  } else {
    currentDuration = duration;
  }

  int minutes = currentDuration ;

  lcd.setCursor(0, 0);
  lcd.print("Time: ");
  lcd.print(minutes);
  lcd.print(" min");

  lcd.setCursor(0, 1);
  lcd.print("Worker: ");
  lcd.print(workerName);

  delay(500);
}