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

// LCD setup (common I2C addresses: 0x27 or 0x3F)
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Keypad setup
const byte ROWS = 4, COLS = 4;
char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {9, 8, 7, 6};
byte colPins[COLS] = {5, 4, 3, 2};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Game state
int a, b, correctAnswer;
char operation;
String userInput = "";
int difficulty = 0;  // 0: easy, 1: medium, 2: hard
int score = 0, total = 0;
int highScore = 0;
int strikes = 0;

void setup() {
  Wire.begin();
  lcd.init();
  lcd.backlight();
  randomSeed(analogRead(0));
  highScore = EEPROM.read(0);
  showMenu();
}

void loop() {
  char key = keypad.getKey();
  if (key) {
    if (key == 'A') { difficulty = 0; startGame(); }
    else if (key == 'B') { difficulty = 1; startGame(); }
    else if (key == 'C') { difficulty = 2; startGame(); }

    if (key >= '0' && key <= '9') {
      userInput += key;
      lcd.setCursor(0, 1);
      lcd.print("Ans: " + userInput + "      ");
    } else if (key == '#') {
      int userAnswer = userInput.toInt();
      total++;
      lcd.setCursor(0, 1);

      if (userAnswer == correctAnswer) {
        score++;
        lcd.print("Correct!         ");
      } else {
        lcd.print("Wrong! " + String(correctAnswer));
        strikes++;
      }

      if (score > highScore) {
        highScore = score;
        EEPROM.update(0, highScore);
      }

      delay(2000);

      if (strikes >= 3) {
        lcd.clear();
        lcd.setCursor(3, 0);
        lcd.print("GAME OVER");
        lcd.setCursor(1, 1);
        lcd.print("Score: " + String(score));
        delay(3000);
        showMenu();
        return;
      }

      askNewQuestion();
    } else if (key == '*') {
      userInput = "";
      lcd.setCursor(0, 1);
      lcd.print("Ans:             ");
    }
  }
}

void startGame() {
  score = 0;
  total = 0;
  strikes = 0;
  askNewQuestion();
}

void askNewQuestion() {
  int minVal = 1, maxVal;
  byte opCount;

  if (difficulty == 0) {
    maxVal = 9;
    opCount = 1; // only +
  } else if (difficulty == 1) {
    maxVal = 99;
    opCount = 2; // + and -
  } else {
    maxVal = 999;
    opCount = 4; // + - * /
  }

  a = random(minVal, maxVal + 1);
  b = random(minVal, maxVal + 1);

  int op = random(0, opCount); // Only from allowed ops

  switch (op) {
    case 0: operation = '+'; correctAnswer = a + b; break;
    case 1: operation = '-'; correctAnswer = a - b; break;
    case 2: operation = '*'; correctAnswer = a * b; break;
    case 3:
      b = random(1, maxVal);
      correctAnswer = random(1, maxVal / b);
      a = b * correctAnswer;
      operation = '/';
      break;
  }

  userInput = "";
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(String(a) + operation + String(b) + " = ?");
  lcd.setCursor(0, 1);
  lcd.print("Ans: ");
  showScore();
}

void showScore() {
  lcd.setCursor(9, 1);
  lcd.print("S:");
  lcd.print(score);
  lcd.print("/");
  lcd.print(total);

  // Show strikes in top-right corner
  lcd.setCursor(13, 0);
  for (int i = 0; i < 3; i++) {
    if (i < strikes) lcd.print("X");
    else lcd.print(" ");
  }
}

void showMenu() {
  userInput = "";
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Press A/B/C to");
  lcd.setCursor(0, 1);
  lcd.print("Choose Level");
}