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

// Definición de pines
#define SDA D4
#define SCL D5
#define potX D1
#define potY D2
#define startButton D0

// Características de la pantalla
#define height 64
#define width 128
#define rst -1

Adafruit_SSD1306 display(width, height, &Wire, rst);

// ====== ESTADOS DEL JUEGO ======
enum GameState {
  WAIT_START,
  PLAYING,
  GAME_OVER
};

GameState gameState = WAIT_START;
volatile bool startRequested = false;

// ====== VARIABLES DEL JUEGO ======
int posX = 64 - 4, posY = 30;
int palX = 64 - 12, palY = 64 - 1;
int vel = 4;
int velX = 5, velY = -2;

int centro[2] = {2048, 2048};

// ====== INTERRUPCIÓN ======
void IRAM_ATTR handleStart() {
  startRequested = true;
}
// ====== SETUP ======
void setup() {
  Serial.begin(115200);
  Wire.begin();

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("Oled Display NOT Found...");
    for (;;);
  }

  pinMode(startButton, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(startButton), handleStart, FALLING);

  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(15, 10);
  display.println("PONG BALL");
  display.display();
  delay(2000);
}

// ====== LOOP PRINCIPAL ======
void loop() {

  switch (gameState) {

    case WAIT_START:
      mostrarPantallaInicio();
      if (startRequested) {
        startRequested = false;
        resetGame();
        gameState = PLAYING;
      }
      break;

    case PLAYING:
      play();
      break;

    case GAME_OVER:
      mostrarGameOver();
      if (startRequested) {
        startRequested = false;
        resetGame();
        gameState = PLAYING;
      }
      break;
  }
}



// ====== PANTALLAS ======
void mostrarPantallaInicio() {
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(20, 15);
  display.println("READY?");
  display.setTextSize(1);
  display.setCursor(20, 40);
  display.println("Press Button");
  display.display();
}

void mostrarGameOver() {
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(30, 20);
  display.println("GAME");
  display.setCursor(30, 40);
  display.println("OVER");
  display.display();
}

// ====== RESET ======
void resetGame() {
  posX = 64 - 4;
  posY = 30;
  palX = 64 - 12;
  velX = 5;
  velY = -2;
}

// ====== JUEGO ======
void play() {

  int lectura = analogRead(potX);

  if (lectura - centro[0] > 100) palX -= vel;
  if (lectura - centro[0] < -100) palX += vel;

  moverBola();

  display.clearDisplay();
  pintarPaleta();
  pintarBola(posX, posY);
  display.display();

  delay(40);
}

// ====== FÍSICA ======
void moverBola() {

  posX += velX;
  posY += velY;

  // Rebote lateral
  if (posX >= width - 4) {
    posX = width - 4;
    velX = -velX;
  }

  if (posX <= 1) {
    posX = 1;
    velX = -velX;
  }

  // Rebote superior
  if (posY <= 1) {
    posY = 1;
    velY = -velY;
  }

  // Colisión inferior
  if (posY >= height - 6) {

    posY = height - 6;

    if (posX + 4 >= palX && posX <= palX + 24) {
      velY = -velY;  // rebote
    } else {
      gameState = GAME_OVER;
    }
  }
}

// ====== DIBUJO ======
void pintarBola(int x, int y) {
  display.fillRect(x, y, 4, 4, WHITE);
}

void pintarPaleta() {
  if (palX > 103) palX = 103;
  if (palX < 1) palX = 1;
  display.fillRect(palX, palY, 24, 2, WHITE);
}