// Define the button pin
#define buttonPin 2 

// State variables for managing LED states and button debouncing
volatile int ledState = 0;          // Keeps track of the current LED pattern (0 = all off, 1 = LED1 on, etc.)

void setup() {
  // Set pins for LEDs (Pin 13, 12, and 11) as outputs
  DDRB |= (1 << PB5) | (1 << PB4) | (1 << PB3);  // Configure PB5, PB4, PB3 as outputs for LEDs

  // Attach an interrupt to the button pin to trigger the interrupt on a FALLING edge (button press)
  attachInterrupt(digitalPinToInterrupt(buttonPin), IntCallback, FALLING);

  // Set the button pin (pin 2) as an input
  DDRD &= ~(1 << PD2);  // Pin 2 (PD2) set as input
}

void loop() {
  // The main loop is empty because the button press is handled via interrupts
  // No need for continuous polling of the button in the loop
}

// Interrupt callback function that handles button press
void IntCallback() {
  // Cycle through LED patterns on each button press
  if (ledState < 3) {
    ledState++;  // Move to the next LED state (1 -> 2 -> 3)
  } else {
    ledState = 0;  // Reset to the first LED state (0 = all off)
  }

  // Update the LEDs based on the current ledState
  updateLEDs();
}

// Function to update LEDs based on the current state
void updateLEDs() {
  // Control LEDs based on the value of ledState
  if (ledState == 1) {
    // Turn on only LED 1 (Pin 13), keep the others off
    PORTB |= (1 << PB5);  // Set PB5 high (LED 1 ON)
  } else if (ledState == 2) {
    // Turn on LED 2 (Pin 12), keep the others off
    PORTB &= ~(1 << PB5); // Set PB5 low (LED 1 OFF)
    PORTB |= (1 << PB4);  // Set PB4 high (LED 2 ON)
  } else if (ledState == 3) {
    // Turn on LED 3 (Pin 11), keep the others off
    PORTB &= ~(1 << PB4); // Set PB4 low (LED 2 OFF)
    PORTB |= (1 << PB3);  // Set PB3 high (LED 3 ON)
  } else {
    // Turn off all LEDs
    PORTB &= ~(1 << PB3); // Set PB3 low (LED 3 OFF)
  }
}