#define YELLOW_LED 9

#define GREEN_LED 10

#define RED_LED 11

#define BLUE_LED 12

#define YELLOW_BTN 2

#define GREEN_BTN 3

#define RED_BTN 4

#define BLUE_BTN 5

int sequence[100];

int level = 0;

void setup() {

  pinMode(YELLOW_LED, OUTPUT);

  pinMode(GREEN_LED, OUTPUT);

  pinMode(RED_LED, OUTPUT);

  pinMode(BLUE_LED, OUTPUT);

  pinMode(YELLOW_BTN, INPUT_PULLUP);

  pinMode(GREEN_BTN, INPUT_PULLUP);

  pinMode(RED_BTN, INPUT_PULLUP);

  pinMode(BLUE_BTN, INPUT_PULLUP);

  randomSeed(analogRead(A0));

  nextRound();

}

void loop() {

  for (int i = 0; i < level; i++) {

    int btn = waitForButton();

    if (btn != sequence[i]) {

      gameOver();

      return;

    }

  }

  delay(500);

  nextRound();

}

void nextRound() {

  sequence[level] = random(0, 4);

  level++;

  for (int i = 0; i < level; i++) {

    showColor(sequence[i]);

    delay(300);

  }

}

int waitForButton() {

  while (true) {

    if (!digitalRead(YELLOW_BTN)) {

      showColor(0);

      return 0;

    }

    if (!digitalRead(GREEN_BTN)) {

      showColor(1);

      return 1;

    }

    if (!digitalRead(RED_BTN)) {

      showColor(2);

      return 2;

    }

    if (!digitalRead(BLUE_BTN)) {

      showColor(3);

      return 3;

    }

  }

}

void showColor(int color) {

  int led;

  if (color == 0) led = YELLOW_LED;

  if (color == 1) led = GREEN_LED;

  if (color == 2) led = RED_LED;

  if (color == 3) led = BLUE_LED;

  digitalWrite(led, HIGH);

  delay(400);

  digitalWrite(led, LOW);

}

void gameOver() {

  for (int i = 0; i < 3; i++) {

    digitalWrite(RED_LED, HIGH);

    digitalWrite(GREEN_LED, HIGH);

    digitalWrite(BLUE_LED, HIGH);

    digitalWrite(YELLOW_LED, HIGH);

    delay(200);

    digitalWrite(RED_LED, LOW);

    digitalWrite(GREEN_LED, LOW);

    digitalWrite(BLUE_LED, LOW);

    digitalWrite(YELLOW_LED, LOW);

    delay(200);

  }

  level = 0;

  delay(500);

  nextRound();

}