unsigned long timerDuration = 210000; // 3.5 minutes in milliseconds
unsigned long flashDuration = 30000; // 30 seconds Flashing duration after the initial timer in milliseconds
unsigned long startTime = 0; // Variable to store the start time
int ledPin = 13; // LED connected to digital pin 13
int doorSwitchPin = 2; // door switch connected to digital pin 2
bool doorOpened = false; // Flag to track door state
bool timerStarted = false; // Flag to track timer state
bool flashMode = false; // Flag to indicate flashing mode

void setup() {
  pinMode(ledPin, OUTPUT); // Set the LED pin as an output
  pinMode(doorSwitchPin, INPUT_PULLUP); // Set the door switch pin as input with internal pull-up resistor
}

void loop() {
  // Check the state of the door switch
  if (digitalRead(doorSwitchPin) == LOW) {
    doorOpened = true; // door is opened
  } else {
    doorOpened = false; // door is closed
  }

  if (doorOpened && !timerStarted) {
    //door is opened and timer is not started
    startTime = millis(); // Save the current time as the start time
    timerStarted = true; // Set the flag to indicate timer started
  }

  if (timerStarted) {
    unsigned long currentTime = millis(); // Get the current time

    if (!flashMode) {
      unsigned long elapsedTime = currentTime - startTime; // Calculate elapsed time

      if (elapsedTime < timerDuration) { // Countdown timer
        // LED off during the countdown
        digitalWrite(ledPin, LOW);
      } else {
        // Timer finished, turn on the LED
        digitalWrite(ledPin, HIGH);
        flashMode = true; // Set the flag for flashing mode
        startTime = currentTime; // Reset the start time for flashing
      }
    } else {
      unsigned long flashElapsedTime = currentTime - startTime; // Calculate elapsed time for flashing

      if (flashElapsedTime < flashDuration) {
        // Flash the LED every 1 second
        if (flashElapsedTime % 1000 < 500) {
          digitalWrite(ledPin, HIGH); // Turn on the LED for half of the second
        } else {
          digitalWrite(ledPin, LOW); // Turn off the LED for the other half of the second
        }
      } else {
        flashMode = false; // End flashing mode
        digitalWrite(ledPin, LOW); // Turn off the LED
      }
    }
  }
}