#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define RESET_PIN -1

const int btn_kiri = 6;
const int btn_atas = 7;
const int btn_kanan = 5;
const int btn_bawah = 4;
const int btn_okay = 3;

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, RESET_PIN);

int snakeX = SCREEN_WIDTH / 2;
int snakeY = SCREEN_HEIGHT / 2;
int foodX, foodY;
int snakeSpeed = 40;
int snakeLength = 1;
bool gameOver = false;

void setup() {
  Serial.begin(115200);
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("SSD1306 allocation failed");
    for (;;);
  }

  pinMode(btn_atas, INPUT_PULLUP);
  pinMode(btn_kiri, INPUT_PULLUP);
  pinMode(btn_bawah, INPUT_PULLUP);
  pinMode(btn_kanan, INPUT_PULLUP);
  pinMode(btn_okay, INPUT_PULLUP);

  randomSeed(analogRead(0));

  resetGame();
}

void loop() {
  if (!gameOver) {
    moveSnake();
    checkCollision();
    generateFood();
    displayGame();
    delay(100);
  } else {
    displayGameOver();
    delay(1000);
    resetGame();
  }
}

void resetGame() {
  snakeX = SCREEN_WIDTH / 2;
  snakeY = SCREEN_HEIGHT / 2;
  snakeSpeed = 1;
  snakeLength = 1;
  gameOver = false;
}

void moveSnake() {
  if (digitalRead(btn_kanan) == LOW) {
    snakeX += snakeSpeed;
  } else if (digitalRead(btn_kiri) == LOW) {
    snakeX -= snakeSpeed;
  } else if (digitalRead(btn_bawah) == LOW) {
    snakeY += snakeSpeed;
  } else if (digitalRead(btn_atas) == LOW) {
    snakeY -= snakeSpeed;
  }
}

void checkCollision() {
  if (snakeX >= SCREEN_WIDTH || snakeX < 0 || snakeY >= SCREEN_HEIGHT || snakeY < 0) {
    gameOver = true;
  }
  if (snakeX == foodX && snakeY == foodY) {
    foodX = random(SCREEN_WIDTH);
    foodY = random(SCREEN_HEIGHT);
    snakeLength++;
  }
}

void generateFood() {
  if (snakeLength > 0) {
    display.setCursor(foodX, foodY);
    display.println('A');
    display.display();
  }
}

void displayGame() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(snakeX, snakeY);
  for (int i = 0; i < snakeLength; i++) {
    display.println('S');
  }
  display.display();
}

void displayGameOver() {
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(10, SCREEN_HEIGHT / 2 - 10);
  display.println("Game Over");
  display.display();
  delay(1000);
}