#include <Arduino.h>

// Pin assignments
const int ledPins[] = {2, 3, 4, 5};   // LED pins
const int buttonPins[] = {6, 7, 8, 9}; // Button pins
const int buzzerPin = 10;              // Buzzer pin

// Frequencies for each button
const int tones[] = {262, 330, 392, 494}; // C4, E4, G4, B4

// Game variables
const int sequenceMaxLength = 20;     // Maximum sequence length
int sequence[sequenceMaxLength];      // Stores the LED sequence
int sequenceLength = 0;               // Current sequence length
int playerIndex = 0;                  // Tracks player's progress
bool gameActive = false;              // Game status

// Function prototypes
void waitForStart();
void playSequence();
void getPlayerInput();
void lightLed(int index);
void turnOffLeds();
void gameOver();
void startGame();
void ledChaseEffect(int durationMs);

void setup() {
  // Configure LED and buzzer pins as outputs
  for (int i = 0; i < 4; i++) {
    pinMode(ledPins[i], OUTPUT);
    digitalWrite(ledPins[i], LOW);
  }
  pinMode(buzzerPin, OUTPUT);
  digitalWrite(buzzerPin, LOW);

  // Configure button pins as inputs with pull-up resistors
  for (int i = 0; i < 4; i++) {
    pinMode(buttonPins[i], INPUT_PULLUP);
  }

  // Initialize random seed
  randomSeed(analogRead(A0));

  // Wait for the player to start the game
  waitForStart();
}

void loop() {
  if (gameActive) {
    playSequence();
    getPlayerInput();
  }
}

// Waits for any button to be pressed to start the game
void waitForStart() {
  turnOffLeds();
  while (true) {
    for (int i = 0; i < 4; i++) {
      if (digitalRead(buttonPins[i]) == LOW) { // Button pressed
        lightLed(i); // Light up the LED corresponding to the button pressed
        delay(200);
        turnOffLeds();
        startGame(); // Start the game
        return;
      }
    }
  }
}

// Starts a new game
void startGame() {
  sequenceLength = 1; // Start with one LED in the sequence
  gameActive = true;

  // Generate the initial sequence
  for (int i = 0; i < sequenceMaxLength; i++) {
    sequence[i] = random(0, 4); // Random LED index (0-3)
  }
  delay(1000); // Wait before starting the game
}

// Plays the current sequence
void playSequence() {
  for (int i = 0; i < sequenceLength; i++) {
    lightLed(sequence[i]);
    delay(500); // LED on duration
    turnOffLeds();
    delay(300); // Pause between LEDs
  }
}

// Lights a specific LED and plays its tone
void lightLed(int index) {
  digitalWrite(ledPins[index], HIGH);
  tone(buzzerPin, tones[index], 300); // Play tone for 300ms
}

// Turns off all LEDs
void turnOffLeds() {
  for (int i = 0; i < 4; i++) {
    digitalWrite(ledPins[i], LOW);
  }
}

// Gets input from the player
void getPlayerInput() {
  playerIndex = 0; // Reset player's progress

  while (playerIndex < sequenceLength) {
    for (int i = 0; i < 4; i++) {
      if (digitalRead(buttonPins[i]) == LOW) { // Button pressed
        lightLed(i); // Light the corresponding LED and play tone
        delay(200);  // Short feedback duration
        turnOffLeds(); // Turn off LEDs quickly after feedback

        if (i == sequence[playerIndex]) {
          playerIndex++; // Correct input, move to the next
          delay(100);    // Debounce delay
        } else {
          gameOver();    // Incorrect input
          return;
        }
      }
    }
  }

  // If the player completes the sequence
  sequenceLength++; // Increase the sequence length
  delay(1000);      // Pause before the next round
}

// Ends the game with a buzzer sound and LED chase effect
void gameOver() {
  gameActive = false;

  // Play game-over sound
  for (int i = 0; i < 3; i++) {
    tone(buzzerPin, 200, 500);
    delay(500);
  }

  // Perform LED chase effect for 5 seconds
  ledChaseEffect(5000);

  // Wait for the player to restart
  waitForStart();
}

// Performs an LED chase effect for a given duration (in milliseconds)
void ledChaseEffect(int durationMs) {
  unsigned long startTime = millis();
  while (millis() - startTime < durationMs) {
    for (int i = 0; i < 4; i++) {
      lightLed(i);
      delay(100); // Delay between LED steps
      turnOffLeds();
    }
  }
}