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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define SCREEN_ADDRESS 0x3C

// --- MUX & PINS ---
const int S0 = 0; const int S1 = 1; const int S2 = 2; const int S3 = 3;
const int SIG_PIN = 26; 

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// --- GAME VARIABLES ---
float playerY = 32;
float smoothedInput = 512;
float alpha = 0.2; // Mario-smoothness factor
int wallX = 128;
int gapY = 32;
int score = 0;
bool gameOver = false;

void setup() {
  Wire.setSDA(6); Wire.setSCL(7); Wire.begin();
  pinMode(S0, OUTPUT); pinMode(S1, OUTPUT);
  pinMode(S2, OUTPUT); pinMode(S3, OUTPUT);
  
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) for(;;);
  display.clearDisplay();
}

void resetGame() {
  wallX = 128;
  score = 0;
  gameOver = false;
  gapY = random(10, 50);
}

void loop() {
  if (gameOver) {
    display.clearDisplay();
    display.setTextSize(2);
    display.setCursor(10, 20);
    display.println("GAME OVER");
    display.setTextSize(1);
    display.setCursor(30, 45);
    display.print("Score: "); display.println(score);
    display.display();
    
    // To restart: Turn the pot all the way down and back up
    int r = analogRead(SIG_PIN);
    if (r < 50) resetGame();
    return;
  }

  // 1. SELECT J1 & READ
  digitalWrite(S0, LOW); digitalWrite(S1, LOW);
  digitalWrite(S2, LOW); digitalWrite(S3, LOW);
  int raw = analogRead(SIG_PIN);

  // 2. SMOOTH MOVEMENT (Mario Physics)
  smoothedInput = (alpha * raw) + ((1.0 - alpha) * smoothedInput);
  playerY = map((int)smoothedInput, 0, 1023, SCREEN_HEIGHT - 5, 5);

  // 3. MOVE WALLS
  wallX -= 3; // Game speed
  if (wallX < -10) {
    wallX = 128;
    gapY = random(10, 45); // Randomize the next gap
    score++;
  }

  // 4. COLLISION DETECTION
  // Check if player (X=20) hits the wall (wallX) outside the gap (gapY)
  if (wallX > 15 && wallX < 25) {
    if (playerY < gapY - 8 || playerY > gapY + 8) {
      gameOver = true;
    }
  }

  // 5. DRAWING
  display.clearDisplay();

  // Draw Player (Mario/Square)
  display.fillRect(20, (int)playerY - 2, 5, 5, SSD1306_WHITE);

  // Draw Walls (with a gap)
  display.drawFastVLine(wallX, 0, gapY - 10, SSD1306_WHITE); // Top wall
  display.drawFastVLine(wallX, gapY + 10, SCREEN_HEIGHT, SSD1306_WHITE); // Bottom wall

  // Score
  display.setTextSize(1);
  display.setCursor(0,0);
  display.print("Score: "); display.print(score);

  display.display();
  delay(20);
}