const int ledPins[] = {2, 3, 4, 5};      // LED pins
const int buttonPins[] = {6, 7, 8, 9};   // Button pins
const int buzzerPin = 10;                // Buzzer pin
int sequence[100];                       // Array to store the sequence
int level = 0;                           // Current level of the game

const int notes[] = {262, 294, 330, 349}; // Notes corresponding to each LED

void setup() {
  for (int i = 0; i < 4; i++) {
    pinMode(ledPins[i], OUTPUT);         // Set LED pins as OUTPUT
    pinMode(buttonPins[i], INPUT_PULLUP);// Set button pins as INPUT with internal pull-up resistors
  }
  pinMode(buzzerPin, OUTPUT);            // Set buzzer pin as OUTPUT
  randomSeed(analogRead(0));             // Seed random number generator
  newSequence();                         // Generate the first sequence
}

void loop() {
  showSequence();                        // Show the current sequence
  if (playerTurn()) {                    // Check player's input
    level++;                             // Increase level if correct
    delay(1000);                         // Wait before next level
    newSequence();                       // Generate a new sequence
  } else {
    level = 0;                           // Reset game if wrong
    delay(1000);                         // Wait before restart
    newSequence();                       // Generate a new sequence
  }
}

void newSequence() {
  for (int i = 0; i <= level; i++) {
    sequence[i] = random(4);             // Generate a random number between 0 and 3
  }
}

void showSequence() {
  for (int i = 0; i <= level; i++) {
    int led = sequence[i];
    digitalWrite(ledPins[led], HIGH);     // Turn on LED
    tone(buzzerPin, notes[led], 200);     // Play corresponding tone
    delay(500);                           // Wait
    digitalWrite(ledPins[led], LOW);      // Turn off LED
    delay(500);                           // Wait
  }
}

bool playerTurn() {
  for (int i = 0; i <= level; i++) {
    bool buttonPressed = false;
    while (!buttonPressed) {
      for (int j = 0; j < 4; j++) {
        if (digitalRead(buttonPins[j]) == LOW) {  // Check if button is pressed
          buttonPressed = true;
          if (j != sequence[i]) {
            tone(buzzerPin, 200, 500);             // Play error tone
            return false;                         // If the wrong button is pressed, return false
          }
          tone(buzzerPin, notes[j], 200);         // Play corresponding tone for correct press
          delay(300);                             // Debounce delay
          while (digitalRead(buttonPins[j]) == LOW); // Wait for button release
          delay(300);                             // Debounce delay
        }
      }
    }
  }
  return true;                                    // If all buttons are pressed correctly, return true
}