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

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

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

// Paddle settings
#define PADDLE_WIDTH  20
#define PADDLE_HEIGHT 4
#define PADDLE_Y      (SCREEN_HEIGHT - 6)
int paddleX = (SCREEN_WIDTH - PADDLE_WIDTH) / 2;

// Ball settings
const int ballSize = 3;
int ballX, ballY;
int ballDX, ballDY;

// Buttons
const int buttonLeftPin = 2;
const int buttonRightPin = 3;

// Game state
bool gameRunning = true;
int score = 0;
int level = 1;
int baseSpeed = 10;  // Base delay in ms
int gameSpeed = baseSpeed;
int minSpeed = 2;    // Minimum speed (i.e., max ball speed)

void setup() {
  pinMode(buttonLeftPin, INPUT_PULLUP);
  pinMode(buttonRightPin, INPUT_PULLUP);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    while (true); // OLED not found
  }

  display.clearDisplay();
  display.display();

  resetGame();
}

void loop() {
  if (gameRunning) {
    // Button controls
    bool moveLeft = digitalRead(buttonLeftPin) == LOW;
    bool moveRight = digitalRead(buttonRightPin) == LOW;

    if (moveLeft && paddleX > 0) paddleX -= 2;
    if (moveRight && paddleX < SCREEN_WIDTH - PADDLE_WIDTH) paddleX += 2;

    // Ball movement
    ballX += ballDX;
    ballY += ballDY;

    // Bounce from walls
    if (ballX <= 0 || ballX >= SCREEN_WIDTH - ballSize) ballDX *= -1;
    if (ballY <= 0) ballDY *= -1;

    // Paddle collision
    if (ballY + ballSize >= PADDLE_Y && ballY + ballSize <= PADDLE_Y + PADDLE_HEIGHT) {
      if (ballX + ballSize >= paddleX && ballX <= paddleX + PADDLE_WIDTH) {
        ballDY *= -1;
        ballY = PADDLE_Y - ballSize;
        score++;

        // 🆕 Update level every 10 points
        level = (score / 10) + 1;

        // Adjust speed
        gameSpeed = baseSpeed - (level - 1);
        if (gameSpeed < minSpeed) gameSpeed = minSpeed;
      }
    }

    // Missed paddle
    if (ballY > SCREEN_HEIGHT) {
      gameRunning = false;
      delay(1000); // Show missed ball for a moment
      showGameOver();
      waitForRestart();
    }

    // Drawing
    display.clearDisplay();

    // Paddle
    display.fillRect(paddleX, PADDLE_Y, PADDLE_WIDTH, PADDLE_HEIGHT, SSD1306_WHITE);

    // Ball
    display.fillRect(ballX, ballY, ballSize, ballSize, SSD1306_WHITE);

    // Level and Score
    display.setTextSize(1);
    display.setTextColor(SSD1306_WHITE);
    display.setCursor(0, 0);
    display.print("Lvl: ");
    display.print(level);

    display.setCursor(64, 0);
    display.print("Score: ");
    display.print(score);

    display.display();

    delay(gameSpeed);
  }
}

void resetGame() {
  paddleX = (SCREEN_WIDTH - PADDLE_WIDTH) / 2;
  ballX = SCREEN_WIDTH / 2;
  ballY = SCREEN_HEIGHT / 2;
  ballDX = 1;
  ballDY = -1;
  score = 0;
  level = 1;
  gameSpeed = baseSpeed;
  gameRunning = true;
  display.clearDisplay();
}

void showGameOver() {
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);

  // Line 1: Game Over
  display.setTextSize(1);
  display.setCursor((SCREEN_WIDTH - 12 * 6) / 2, 5);
  display.println("Game Over");

  // Line 2: Level and Score
  display.setTextSize(1);
  String scoreText = "Level: " + String(level) + "  Score: " + String(score);
  int16_t x1, y1;
  uint16_t w, h;
  display.getTextBounds(scoreText, 0, 0, &x1, &y1, &w, &h);
  display.setCursor((SCREEN_WIDTH - w) / 2, 32);
  display.println(scoreText);

  // Line 3: Restart prompt
  String restartMsg = "Press any button";
  display.getTextBounds(restartMsg, 0, 0, &x1, &y1, &w, &h);
  display.setCursor((SCREEN_WIDTH - w) / 2, 48);
  display.println(restartMsg);

  display.display();
}

void waitForRestart() {
  while (true) {
    if (digitalRead(buttonLeftPin) == LOW || digitalRead(buttonRightPin) == LOW) {
      resetGame();
      break;
    }
    delay(100);
  }
}