study-wheel/index.html at main · developersuryaa/study-wheel · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>Study Subject Spin Wheel</title>
  <style>
    :root{--bg1:#4facfe;--bg2:#00f2fe}
    *{box-sizing:border-box}
    body{
      display:flex;flex-direction:column;align-items:center;justify-content:center;height:100vh;margin:0;
      background:linear-gradient(135deg,var(--bg1),var(--bg2));font-family:Poppins,system-ui,Segoe UI,Roboto; color:#fff;
    }
    .card{background:rgba(255,255,255,0.06);padding:28px;border-radius:20px;box-shadow:0 8px 30px rgba(0,0,0,0.25);text-align:center}
    canvas{display:block;margin:0 auto;max-width:420px;max-height:420px}
    #spinBtn{margin-top:18px;padding:12px 22px;font-size:16px;background:#fff;color:#111;border:none;border-radius:12px;cursor:pointer;transition:transform .15s}
    #spinBtn:active{transform:scale(.98)}
    #result{margin-top:14px;height:34px;font-weight:700;opacity:0;transform:translateY(6px);transition:opacity .45s,transform .45s}

    /* pointer */
    .pointer{width:0;height:0;border-left:18px solid transparent;border-right:18px solid transparent;border-bottom:28px solid #fff;position:relative;top:-18px;margin-bottom:-8px}
  </style>
</head>
<body>
  <div class="card">
    <h1 style="margin:0 0 12px 0">🎯 Study Subject Spin Wheel</h1>
    <div class="pointer" aria-hidden="true"></div>
    <canvas id="wheel" width="420" height="420" role="img" aria-label="Subject spin wheel"></canvas>

    <button id="spinBtn">Spin 🎡</button>
    <div id="result"> </div>
  </div>

  <script>
    // Subjects + colors
    const subjects = ['Compulsory Maths','Optional Maths','Science','Nepali','Social Studies','Education','English'];
    const colors = ['#ff6384','#36a2eb','#ffce56','#4bc0c0','#9966ff','#ff9f40','#ffcd56'];

    // Canvas setup
    const canvas = document.getElementById('wheel');
    const ctx = canvas.getContext('2d');
    const cx = canvas.width/2, cy = canvas.height/2, radius = Math.min(cx,cy)-12;
    const segmentCount = subjects.length;
    const segAngle = (Math.PI*2)/segmentCount;

    let rotation = 0; // current rotation in radians
    let isSpinning = false;
    let highlightIndex = -1; // hovered segment index

    function drawWheel(){
      ctx.clearRect(0,0,canvas.width,canvas.height);

      for(let i=0;i<segmentCount;i++){
        const start = rotation + i*segAngle;
        const end = start + segAngle;

        // default fill: WHITE (user asked white when not hover)
        ctx.beginPath();
        ctx.moveTo(cx,cy);
        ctx.arc(cx,cy,radius,start,end);
        ctx.closePath();

        if(i === highlightIndex){
          ctx.fillStyle = colors[i]; // show color on hover
        } else if(isSpinning && i===highlightIndex){
          ctx.fillStyle = colors[i];
        } else {
          ctx.fillStyle = '#ffffff'; // default white
        }
        ctx.fill();

        // colored border so segments are visible even when white
        ctx.strokeStyle = colors[i];
        ctx.lineWidth = 4;
        ctx.stroke();

        // label - always shown in contrasting color (dark) on white, and white on colored fill
        ctx.save();
        // label angle and position
        const mid = (start+end)/2;
        const labelX = cx + Math.cos(mid)*(radius*0.62);
        const labelY = cy + Math.sin(mid)*(radius*0.62);
        ctx.translate(labelX,labelY);
        ctx.rotate(mid + Math.PI/2);
        ctx.font = 'bold 14px sans-serif';
        ctx.textAlign = 'center';
        ctx.textBaseline = 'middle';
        if(i === highlightIndex){ ctx.fillStyle = '#fff'; } else { ctx.fillStyle = '#111'; }
        // small padding background to make text readable
        ctx.fillText(subjects[i],0,0);
        ctx.restore();
      }

      // center circle
      ctx.beginPath();ctx.arc(cx,cy,52,0,Math.PI*2);ctx.fillStyle='rgba(0,0,0,0.12)';ctx.fill();
    }

    // initial draw
    drawWheel();

    // pointer top position used to determine which segment is at pointer
    function indexAtPointer(){
      // pointer points at angle -90deg (i.e. -pi/2) relative to canvas center
      const pointerAngle = (-Math.PI/2 - rotation) % (Math.PI*2);
      // normalize
      let a = pointerAngle;
      if(a<0) a += Math.PI*2;
      const idx = Math.floor(a/segAngle) % segmentCount;
      return (segmentCount + idx) % segmentCount;
    }

    // hover handling
    canvas.addEventListener('mousemove', (e)=>{
      if(isSpinning) return; // ignore hover while spinning
      const rect = canvas.getBoundingClientRect();
      const x = e.clientX - rect.left - cx;
      const y = e.clientY - rect.top - cy;
      const angle = Math.atan2(y,x);
      // convert to wheel space (rotation applied)
      let adjusted = angle - rotation;
      while(adjusted < 0) adjusted += Math.PI*2;
      const idx = Math.floor(adjusted/segAngle) % segmentCount;
      highlightIndex = idx;
      drawWheel();
    });

    canvas.addEventListener('mouseleave', ()=>{ if(!isSpinning){ highlightIndex = -1; drawWheel(); } });

    // Spin animation
    const spinBtn = document.getElementById('spinBtn');
    const resultDiv = document.getElementById('result');

    function easeOutCubic(t){ return 1 - Math.pow(1-t,3); }

    function spinToIndex(targetIndex){
      if(isSpinning) return;
      isSpinning = true;
      resultDiv.style.opacity = 0; resultDiv.style.transform = 'translateY(6px)';

      // calculate target rotation so that targetIndex lands at pointer (-pi/2)
      // current rotation + spins*2pi + offset = -pi/2 - targetIndex*segAngle - segAngle/2 (centered)
      const current = rotation % (Math.PI*2);
      const randSpins = 3 + Math.floor(Math.random()*3); // 3 to 5 full spins
      const targetAngle = -Math.PI/2 - (targetIndex + 0.5)*segAngle; // center of segment at pointer
      // compute delta to rotate from current to targetAngle plus extra spins
      let delta = (randSpins * Math.PI*2) + (targetAngle - current);
      // ensure delta positive large enough
      if(delta < 0) delta += Math.PI*2;
      const duration = 3000 + Math.floor(Math.random()*800); // ms
      const start = performance.now();

      function frame(now){
        const elapsed = now - start;
        const t = Math.min(1, elapsed / duration);
        const eased = easeOutCubic(t);
        rotation = current + delta * eased;
        drawWheel();

        if(t < 1){ requestAnimationFrame(frame); }
        else { // finished
          isSpinning = false;
          // final index correction
          rotation = current + delta;
          highlightIndex = targetIndex;
          drawWheel();
          // flash the selected segment with small pulse
          flashSelected(targetIndex);
        }
      }
      requestAnimationFrame(frame);
    }

    function flashSelected(i){
      const times = 6;
      let count=0;
      const orig = highlightIndex;
      const iv = setInterval(()=>{
        highlightIndex = (count%2===0)?i:-1;
        drawWheel();
        count++;
        if(count>times){ clearInterval(iv); highlightIndex = i; drawWheel(); showResult(i); }
      },120);
    }

    function showResult(i){
      resultDiv.textContent = `📘 You should study: ${subjects[i]}!`;
      resultDiv.style.opacity = 1; resultDiv.style.transform='translateY(0)';
      // small confetti-like CSS animation could be added, but keeping lightweight
    }

    // On click, pick random index and spin
    spinBtn.addEventListener('click', ()=>{
      if(isSpinning) return;
      const rand = Math.floor(Math.random()*segmentCount);
      spinToIndex(rand);
    });

    // Allow keyboard spin with Space or Enter
    document.addEventListener('keydown',(e)=>{ if(e.code==='Space' || e.key==='Enter'){ e.preventDefault(); spinBtn.click(); } });

    // In case user wants to programmatically choose a subject later
    // expose function to window
    window.spinTo = (idx)=>{ if(typeof idx==='number' && idx>=0 && idx<segmentCount) spinToIndex(idx); }
  </script>
</body>
</html>