#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>

#define TFT_CS   10
#define TFT_DC   9
#define TFT_RST  8

#define JOY_X    A0
#define JOY_Y    A1

Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_RST);

const int gridSize = 10;
const int maxLength = 100;
int snakeX[maxLength], snakeY[maxLength];
int length = 5;
int dirX = 1, dirY = 0;
int foodX, foodY;
bool gameOver = false;
unsigned long lastMove = 0;
int moveInterval = 150;

void setup() {
  tft.begin();
  tft.setRotation(1);
  tft.fillScreen(ILI9341_BLACK);

  for (int i = 0; i < length; i++) {
    snakeX[i] = 50 - i * gridSize;
    snakeY[i] = 50;
  }

  spawnFood();
}

void loop() {
  if (gameOver) return;

  readJoystick();

  if (millis() - lastMove > moveInterval) {
    moveSnake();
    lastMove = millis();
  }
}

void readJoystick() {
  int xVal = analogRead(JOY_X);
  int yVal = analogRead(JOY_Y);

  if (xVal < 400 && dirX != 1) { dirX = -1; dirY = 0; }
  else if (xVal > 600 && dirX != -1) { dirX = 1; dirY = 0; }

  if (yVal < 400 && dirY != 1) { dirX = 0; dirY = -1; }
  else if (yVal > 600 && dirY != -1) { dirX = 0; dirY = 1; }
}

void moveSnake() {
  tft.fillRect(snakeX[length - 1], snakeY[length - 1], gridSize, gridSize, ILI9341_BLACK);

  for (int i = length - 1; i > 0; i--) {
    snakeX[i] = snakeX[i - 1];
    snakeY[i] = snakeY[i - 1];
  }

  snakeX[0] += dirX * gridSize;
  snakeY[0] += dirY * gridSize;

  if (snakeX[0] < 0 || snakeX[0] >= tft.width() ||
      snakeY[0] < 0 || snakeY[0] >= tft.height()) {
    endGame();
    return;
  }

  for (int i = 1; i < length; i++) {
    if (snakeX[0] == snakeX[i] && snakeY[0] == snakeY[i]) {
      endGame();
      return;
    }
  }

  if (snakeX[0] == foodX && snakeY[0] == foodY) {
    if (length < maxLength) length++;
    spawnFood();
  }

  tft.fillRect(snakeX[0], snakeY[0], gridSize, gridSize, ILI9341_GREEN);
}

void spawnFood() {
  foodX = random(0, tft.width() / gridSize) * gridSize;
  foodY = random(0, tft.height() / gridSize) * gridSize;
  tft.fillRect(foodX, foodY, gridSize, gridSize, ILI9341_RED);
}

void endGame() {
  gameOver = true;
  tft.setCursor(60, 100);
  tft.setTextColor(ILI9341_WHITE);
  tft.setTextSize(2);
  tft.println("Game Over!");
}