Script.js

// ===================================================
//  CalcAI — script.js
//  AI Calculator Logic
// ===================================================

// ===== STATE =====
let current    = '0';    // Jo number screen pe dikh raha hai
let prev       = '';     // Pehla number (operator se pehle)
let operator   = '';     // +, -, *, /
let justCalced = false;  // Abhi = daba ke aaya?

// ===== DOM ELEMENTS =====
const resultEl = document.getElementById('result');
const exprEl   = document.getElementById('expression');
const histEl   = document.getElementById('history');
const aiMsgEl  = document.getElementById('aiMsg');

// ===== OPERATOR SYMBOL MAP =====
const opSymbol = { '*': '×', '/': '÷', '-': '−', '+': '+' };

// ===================================================
//  DISPLAY UPDATE
// ===================================================
function updateDisplay() {
  // Main result
  resultEl.textContent = current;

  // Auto font size based on length
  const len = current.replace('-', '').replace('.', '').length;
  resultEl.className = 'result-line ' + (
    len <= 7  ? 'size-xl' :
    len <= 10 ? 'size-lg' :
    len <= 14 ? 'size-md' : 'size-sm'
  );

  // Expression line (e.g. "5 ×")
  if (prev && operator) {
    exprEl.textContent = prev + ' ' + opSymbol[operator];
  } else {
    exprEl.textContent = '';
  }
}

// Pop animation on result
function flashPop() {
  resultEl.classList.remove('pop');
  void resultEl.offsetWidth; // reflow trick
  resultEl.classList.add('pop');
}

// ===================================================
//  AI TIPS
// ===================================================
const tips = [
  "Wah! Bahut badhiya! 🎯",
  "Bilkul sahi calculation! ✅",
  "Scientific mode bhi try karein 🔬",
  "Perfect! Kuch aur calculate karein? ✨",
  "Excellent! 🏆",
  "Acha result aaya! 🚀",
  "Tip: % button se percentage nikaalein 💡",
  "Mathematics mein master ho raho! 🌟"
];

function setTip(msg) {
  aiMsgEl.textContent = msg || tips[Math.floor(Math.random() * tips.length)];
}

// ===================================================
//  CLOCK
// ===================================================
function updateClock() {
  const n = new Date();
  document.getElementById('clock').textContent =
    String(n.getHours()).padStart(2, '0') + ':' +
    String(n.getMinutes()).padStart(2, '0');
}
updateClock();
setInterval(updateClock, 1000);

// ===================================================
//  BUTTON HANDLERS
// ===================================================

// Number press (0–9)
function pressNum(n) {
  if (justCalced) {
    current = n;
    prev = '';
    operator = '';
    justCalced = false;
  } else {
    current = current === '0' ? n : current + n;
  }
  updateDisplay();
}

// Operator press (+, -, *, /)
function pressOp(op) {
  // Agar pehle se prev + operator hai toh pehle calculate karo
  if (prev && operator && !justCalced) {
    doCalc(false);
  }
  prev = current;
  operator = op;
  current = '0';
  justCalced = false;
  updateDisplay();
  setTip("Operator diya! Ab doosra number daalo aur = dabao 👇");
}

// Decimal point
function pressDot() {
  if (justCalced) {
    current = '0.';
    justCalced = false;
  } else if (!current.includes('.')) {
    current += '.';
  }
  updateDisplay();
}

// AC — All Clear
function clearAll() {
  current    = '0';
  prev       = '';
  operator   = '';
  justCalced = false;
  histEl.textContent = '';
  updateDisplay();
  setTip("Clear ho gaya! Naya calculation shuru karein 🌟");
}

// Backspace
function backspace() {
  if (justCalced) return;
  current = current.length <= 1 ? '0' : current.slice(0, -1);
  updateDisplay();
}

// Toggle +/−
function toggleSign() {
  if (current === '0') return;
  current = current.startsWith('-') ? current.slice(1) : '-' + current;
  updateDisplay();
}

// Percentage
function percent() {
  current = String(parseFloat(current) / 100);
  updateDisplay();
  setTip("Percentage calculate ho gayi! 💯");
}

// ===================================================
//  CORE CALCULATION
// ===================================================
function doCalc(showHistory = true) {
  const a = parseFloat(prev);
  const b = parseFloat(current);

  if (isNaN(a) || isNaN(b) || !operator) return;

  let res;
  switch (operator) {
    case '+': res = a + b; break;
    case '-': res = a - b; break;
    case '*': res = a * b; break;
    case '/':
      if (b === 0) {
        current  = 'Error';
        prev     = '';
        operator = '';
        updateDisplay();
        setTip("Zero se divide nahi hota! ⚠️");
        return;
      }
      res = a / b;
      break;
    default: return;
  }

  if (showHistory) {
    histEl.textContent = prev + ' ' + opSymbol[operator] + ' ' + current + ' =';
  }

  // Float precision fix
  current    = parseFloat(res.toFixed(10)).toString();
  prev       = '';
  operator   = '';
  justCalced = true;

  flashPop();
}

// = button
function calculate() {
  if (!prev || !operator) return;
  doCalc(true);
  updateDisplay();
  setTip(tips[Math.floor(Math.random() * tips.length)]);
}

// ===================================================
//  SCIENTIFIC FUNCTIONS
// ===================================================
function sciFunc(fn) {
  const val = parseFloat(current);
  let res, msg;

  switch (fn) {
    case 'sin':
      res = Math.sin(val * Math.PI / 180);
      msg = 'sin(' + val + '°) = ' + res.toFixed(6) + ' 📐';
      break;
    case 'cos':
      res = Math.cos(val * Math.PI / 180);
      msg = 'cos(' + val + '°) = ' + res.toFixed(6) + ' 📐';
      break;
    case 'tan':
      res = Math.tan(val * Math.PI / 180);
      msg = 'tan(' + val + '°) = ' + res.toFixed(6) + ' 📐';
      break;
    case 'log':
      if (val <= 0) { setTip("log sirf positive numbers ke liye hota hai! ⚠️"); return; }
      res = Math.log10(val);
      msg = 'log(' + val + ') calculate kiya! 🔬';
      break;
    case 'sqrt':
      if (val < 0) { setTip("Negative number ka square root nahi hota! ⚠️"); return; }
      res = Math.sqrt(val);
      msg = '√' + val + ' = ' + res.toFixed(6) + ' ✨';
      break;
    case 'sq':
      res = val * val;
      msg = val + '² = ' + res + ' 💥';
      break;
    case 'pi':
      current = '3.14159265358979';
      histEl.textContent = 'π =';
      updateDisplay();
      setTip("π — ek magical number! 🔵");
      return;
    case 'euler':
      current = '2.71828182845905';
      histEl.textContent = "Euler's e =";
      updateDisplay();
      setTip("e ≈ 2.718 — Euler ka number 🌀");
      return;
    default:
      return;
  }

  histEl.textContent = fn + '(' + val + ') =';
  current    = parseFloat(res.toFixed(10)).toString();
  justCalced = true;

  flashPop();
  updateDisplay();
  setTip(msg);
}

// ===================================================
//  MODE SWITCH (Basic / Scientific / % Tips)
// ===================================================
function setMode(m, btn) {
  // Update active tab
  document.querySelectorAll('.tab').forEach(t => t.classList.remove('active'));
  btn.classList.add('active');

  // Show/hide scientific row
  document.getElementById('sciRow').classList.toggle('show', m === 'sci');

  // Update AI tip
  if (m === 'pct') {
    setTip("Tip Mode: Koi number likho → % dabao → Discount ya tip milega! 💰");
  } else if (m === 'sci') {
    setTip("Scientific mode active! sin, cos, log, √ sab available hain 🔬");
  } else {
    setTip("Basic mode ready hai! Calculate karein ✨");
  }
}

// ===================================================
//  KEYBOARD SUPPORT
// ===================================================
document.addEventListener('keydown', function(e) {
  if (e.key >= '0' && e.key <= '9') pressNum(e.key);
  else if (e.key === '.')           pressDot();
  else if (e.key === '+')           pressOp('+');
  else if (e.key === '-')           pressOp('-');
  else if (e.key === '*')           pressOp('*');
  else if (e.key === '/') { e.preventDefault(); pressOp('/'); }
  else if (e.key === 'Enter' || e.key === '=') calculate();
  else if (e.key === 'Backspace')   backspace();
  else if (e.key === 'Escape')      clearAll();
});

// ===== INIT =====
updateDisplay();