#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Pins
const int trueBtnPin = 2;
const int falseBtnPin = 3;
const int buzzerPin = 8;

int score = 0;
int questionCount = 0;
const int totalQuestions = 10;
bool isAnswerCorrect;

void setup() {
  lcd.begin(16, 2);       // ✅ Correct usage for most I2C LCD libraries
  lcd.backlight();
  pinMode(trueBtnPin, INPUT);
  pinMode(falseBtnPin, INPUT);
  pinMode(buzzerPin, OUTPUT);

  lcd.setCursor(0, 0);
  lcd.print("Algebra Game!");
  delay(2000);
  lcd.clear();

  randomSeed(analogRead(0));
  generateQuestion();
}

void loop() {
  if (digitalRead(trueBtnPin) == HIGH) {
    checkAnswer(true);
    delay(300);
  }

  if (digitalRead(falseBtnPin) == HIGH) {
    checkAnswer(false);
    delay(300);
  }
}

void generateQuestion() {
  lcd.clear();
  int gameType = random(1, 11);  // 1 to 10
  int a = random(1, 11);
  int b = random(1, 11);
  int result;
  int display;
  String q;

  switch (gameType) {
    case 1:  // Addition
      result = a + b;
      display = result + random(-2, 2);
      isAnswerCorrect = (display == result);
      q = String(a) + "+" + String(b) + "=" + String(display);
      break;

    case 2:  // Subtraction
      result = a - b;
      display = result + random(-2, 2);
      isAnswerCorrect = (display == result);
      q = String(a) + "-" + String(b) + "=" + String(display);
      break;

    case 3:  // Multiplication
      result = a * b;
      display = result + random(-2, 2);
      isAnswerCorrect = (display == result);
      q = String(a) + "*" + String(b) + "=" + String(display);
      break;

    case 4:  // Division
      result = a;
      int temp = a * b;
      display = result + random(-1, 2);
      isAnswerCorrect = (display == result);
      q = String(temp) + "/" + String(b) + "=" + String(display);
      break;

    case 5:  // Square
      result = a * a;
      display = result + random(-3, 4);
      isAnswerCorrect = (display == result);
      q = String(a) + "^2=" + String(display);
      break;

    case 6:  // Cube
      result = a * a * a;
      display = result + random(-5, 6);
      isAnswerCorrect = (display == result);
      q = String(a) + "^3=" + String(display);
      break;

    case 7:  // Linear: 2x + 3 = ?
      result = 2 * a + 3;
      display = result + random(-2, 3);
      isAnswerCorrect = (display == result);
      q = "2*" + String(a) + "+3=" + String(display);
      break;

    case 8:  // Quadratic: x^2 + 2x + 1
      result = a * a + 2 * a + 1;
      display = result + random(-3, 4);
      isAnswerCorrect = (display == result);
      q = String(a) + "^2+2*" + String(a) + "+1=" + String(display);
      break;

    case 9:  // x + b = c, find x
      int x = a;
      int c = a + b;
      display = x + random(-1, 2);
      isAnswerCorrect = (display == x);
      q = "x+" + String(b) + "=" + String(c) + ",x=" + String(display);
      break;

    case 10:  // Exponent match
      result = pow(2, a);
      display = result + random(-5, 6);
      isAnswerCorrect = (display == result);
      q = "2^" + String(a) + "=" + String(display);
      break;
  }

  lcd.setCursor(0, 0);
  lcd.print(q.substring(0, 16));
  lcd.setCursor(0, 1);
  lcd.print("Score:" + String(score));
}

void checkAnswer(bool userInput) {
  questionCount++;
  if (userInput == isAnswerCorrect) {
    score++;
    tone(buzzerPin, 1000, 200); // correct
  } else {
    tone(buzzerPin, 300, 500); // wrong
  }

  delay(1000);

  if (questionCount >= totalQuestions) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Game Over");
    lcd.setCursor(0, 1);
    lcd.print("Score: " + String(score));
    while (1); // Freeze game
  } else {
    generateQuestion();
  }
}