FIX: Media Explorer panel preview cho phép zoom in zoom out và copy nội dung

app/static/js/app.jsx

@@ -9009,7 +9009,7 @@ const MEDIA_LIBRARY_SAMPLES = [
   { name: "MIDI_Loop_06.mid", events: 88, lengthQn: 16, time: "0:08.000", tpqn: 480, bpm: 130, kind: "midi" }
 ];
 
-const MediaExplorerPanel = ({ height }) => {
+const MediaExplorerPanel = ({ height, clipboardRef }) => {
   const [userFiles, setUserFiles] = React.useState([]);
   const [folder, setFolder] = React.useState('library');
   const [selected, setSelected] = React.useState(null);
@@ -9034,7 +9034,13 @@ const MediaExplorerPanel = ({ height }) => {
   const [tempo, setTempo] = React.useState(function() {
     var saved = localStorage.getItem('studio_media_explorer_tempo');
     return saved ? parseInt(saved) : 120;
-  }());
+  });
+
+  const [zoom, setZoom] = React.useState(1.0);
+  const [selStart, setSelStart] = React.useState(null);
+  const [selEnd, setSelEnd] = React.useState(null);
+  const [isDragging, setIsDragging] = React.useState(false);
+  const [previewCtxMenu, setPreviewCtxMenu] = React.useState(null); // { x, y }
   // Refs mirror latest state so drawCanvas (also called from rAF clock with a
   // stale closure) always draws the currently selected file, not the old one.
   const selectedRef = React.useRef(null);
@@ -9065,6 +9071,201 @@ const MediaExplorerPanel = ({ height }) => {
   folderRef.current = folder;
   tempoRef.current = tempo;
   currentTimeRef.current = currentTime;
+
+  const getCanvasLayout = () => {
+    const canvas = canvasRef.current;
+    if (!canvas) return { w: 300, h: 100, pxPerBeat: 42, pxPerSec: 84, offset: 0, dur: 0, contentW: 0 };
+    const w = canvas.clientWidth;
+    const h = canvas.clientHeight;
+    const f = selectedRef.current;
+    const isMidi = isMidiFile(f);
+    const curTempo = tempoRef.current || 120;
+    const pxPerBeat = 42 * zoom;
+    const pxPerSec = pxPerBeat * curTempo / 60;
+    const dur = fileDuration(f);
+    
+    let contentW = 0;
+    if (isMidi) {
+      const isRealMidi = midiNotesRef.current && midiNotesRef.current.length && midiTotalBeatsRef.current > 0;
+      const totalBeats = isRealMidi ? Math.max(midiTotalBeatsRef.current, 4) : Math.max(4, Math.ceil(dur * curTempo / 60) || 16);
+      contentW = Math.max(1, totalBeats * pxPerBeat);
+    } else {
+      contentW = Math.max(1, dur * pxPerSec);
+    }
+    
+    let offset = 0;
+    if (isPlayingRef.current && contentW > w && dur > 0) {
+      offset = Math.max(0, Math.min(contentW - w, currentTimeRef.current * pxPerSec - w / 2));
+    }
+    return { w, h, pxPerBeat, pxPerSec, offset, dur, contentW };
+  };
+
+  const getSelectedAudioBuffer = async () => {
+    if (audioBufferRef.current) return audioBufferRef.current;
+    if (!selectedRef.current) return null;
+    const buf = await readLocalFileBuffer(selectedRef.current);
+    if (!buf) return null;
+    try {
+      const ctx = getAudioContext();
+      const decoded = await ctx.decodeAudioData(buf);
+      setAudioBuffer(decoded);
+      return decoded;
+    } catch (e) {
+      console.error(e);
+      return null;
+    }
+  };
+
+  const handleCanvasWheel = (e) => {
+    if (!selected) return;
+    e.preventDefault();
+    const zoomFactor = 1.15;
+    if (e.deltaY < 0) {
+      setZoom(prev => Math.min(10.0, prev * zoomFactor));
+    } else {
+      setZoom(prev => Math.max(0.2, prev / zoomFactor));
+    }
+  };
+
+  const handleCanvasMouseDown = (e) => {
+    if (!selected) return;
+    if (e.button === 2) return; // Right click context menu
+    const canvas = canvasRef.current;
+    if (!canvas) return;
+    const rect = canvas.getBoundingClientRect();
+    const clientX = e.clientX - rect.left;
+    const { pxPerSec, pxPerBeat, offset } = getCanvasLayout();
+    
+    const isMidi = isMidiFile(selected);
+    const value = isMidi 
+      ? (clientX + offset) / pxPerBeat // in beats
+      : (clientX + offset) / pxPerSec; // in seconds
+      
+    setSelStart(value);
+    setSelEnd(value);
+    setIsDragging(true);
+    setPreviewCtxMenu(null);
+  };
+
+  const handleCanvasMouseMove = (e) => {
+    if (!isDragging || !selected) return;
+    const canvas = canvasRef.current;
+    if (!canvas) return;
+    const rect = canvas.getBoundingClientRect();
+    const clientX = e.clientX - rect.left;
+    const { pxPerSec, pxPerBeat, offset } = getCanvasLayout();
+    
+    const isMidi = isMidiFile(selected);
+    const value = isMidi 
+      ? (clientX + offset) / pxPerBeat 
+      : (clientX + offset) / pxPerSec;
+      
+    setSelEnd(value);
+  };
+
+  const handleCanvasMouseUp = (e) => {
+    if (isDragging) {
+      setIsDragging(false);
+    }
+  };
+
+  const handleCanvasContextMenu = (e) => {
+    e.preventDefault();
+    if (!selected || selStart === null || selEnd === null || Math.abs(selStart - selEnd) < 0.01) return;
+    setPreviewCtxMenu({
+      x: e.clientX,
+      y: e.clientY
+    });
+  };
+
+  const handleCopySelection = async () => {
+    if (!selected || selStart === null || selEnd === null) return;
+    const isMidi = isMidiFile(selected);
+    const startVal = Math.min(selStart, selEnd);
+    const endVal = Math.max(selStart, selEnd);
+    
+    if (isMidi) {
+      if (!midiNotes || !midiNotes.length) {
+        window.showToast && window.showToast('Không có dữ liệu MIDI để sao chép', 'warning');
+        return;
+      }
+      
+      const copiedNotes = midiNotes
+        .filter(n => n.start_beat >= startVal && n.start_beat <= endVal)
+        .map(n => ({
+          ...n,
+          start_beat: n.start_beat - startVal
+        }));
+        
+      if (!copiedNotes.length) {
+        window.showToast && window.showToast('Không có note MIDI nào trong vùng chọn', 'warning');
+        return;
+      }
+      
+      const selectDurBeats = endVal - startVal;
+      const secondsPerBeat = 60 / (tempo || 120);
+      const selectDurSec = selectDurBeats * secondsPerBeat;
+      
+      const clipObj = {
+        type: 'midi',
+        notes: copiedNotes,
+        duration: selectDurSec,
+        name: selected.name || 'MIDI Selection',
+        color: '#a855f7'
+      };
+      
+      if (clipboardRef) clipboardRef.current = clipObj;
+      window.globalStudioClipboard = clipObj;
+      
+      window.showToast && window.showToast(`Đã sao chép ${copiedNotes.length} notes MIDI.`, 'success');
+    } else {
+      const activeBuf = await getSelectedAudioBuffer();
+      if (!activeBuf) {
+        window.showToast && window.showToast('Không thể tải dữ liệu âm thanh để sao chép', 'error');
+        return;
+      }
+      
+      const sr = activeBuf.sampleRate;
+      const startSample = Math.floor(startVal * sr);
+      const endSample = Math.floor(endVal * sr);
+      const len = Math.max(1, endSample - startSample);
+      
+      try {
+        const ctx = getAudioContext();
+        const numCh = activeBuf.numberOfChannels || 1;
+        const clipBuffer = ctx.createBuffer(numCh, len, sr);
+        for (let ch = 0; ch < numCh; ch++) {
+          clipBuffer.copyToChannel(activeBuf.getChannelData(ch).subarray(startSample, endSample), ch);
+        }
+        
+        const clipObj = {
+          buffer: clipBuffer,
+          name: selected.name || 'Audio Selection',
+          volumeDb: 0,
+          pan: 0,
+          color: '#10b981',
+          sampleRate: sr,
+          channels: numCh,
+          speed: 1.0
+        };
+        
+        if (clipboardRef) clipboardRef.current = clipObj;
+        window.globalStudioClipboard = clipObj;
+        
+        window.showToast && window.showToast(`Đã sao chép đoạn audio dài ${(len / sr).toFixed(2)}s.`, 'success');
+      } catch (e) {
+        console.error(e);
+        window.showToast && window.showToast('Lỗi khi trích xuất âm thanh vùng chọn', 'error');
+      }
+    }
+  };
+
+  React.useEffect(() => {
+    const handleGlobalClick = () => setPreviewCtxMenu(null);
+    window.addEventListener('click', handleGlobalClick);
+    return () => window.removeEventListener('click', handleGlobalClick);
+  }, []);
+
   const [computerRoots, setComputerRoots] = React.useState(null);
   const [computerTree, setComputerTree] = React.useState({});
   const [computerPath, setComputerPath] = React.useState(null);
@@ -9370,6 +9571,7 @@ const MediaExplorerPanel = ({ height }) => {
   const openMyComputer = async () => {
     setFolder('computer');
     const useClientRoot = async (rootHandle) => {
+      setComputerTree({}); // Dọn sạch cache cây thư mục cũ
       setComputerMode('client');
       setClientRoot(rootHandle);
       const rootEntry = { name: rootHandle.name, path: 'root', is_dir: true, handle: rootHandle };
@@ -9524,12 +9726,27 @@ const MediaExplorerPanel = ({ height }) => {
     // Cố gắng tìm handle trong cây đã load để mở trực tiếp
     const node = computerTree[fav.path];
     if (node && node.handle) {
+      setComputerTree({}); // Reset cache
       browseComputerDir({ ...entry, handle: node.handle });
     } else if (fav.path && fav.path.startsWith('client:')) {
       (async () => {
         let favHandle = null;
         try { favHandle = await loadClientRootHandle(fav.path); } catch (e) {}
         if (favHandle) {
+          // Yêu cầu quyền đọc (permission có thể bị thu hồi)
+          let permitted = true;
+          try {
+            if (typeof favHandle.queryPermission === 'function') {
+              const st = await favHandle.queryPermission({ mode: 'read' });
+              if (st !== 'granted' && typeof favHandle.requestPermission === 'function') {
+                const r = await favHandle.requestPermission({ mode: 'read' });
+                permitted = r === 'granted';
+              }
+            }
+          } catch (e) { permitted = false; }
+
+          if (permitted) {
+            setComputerTree({}); // Reset cache
             setClientRoot(favHandle);
             setComputerMode('client');
             const rootEntry = { name: favHandle.name, path: 'root', is_dir: true, handle: favHandle };
@@ -9537,6 +9754,9 @@ const MediaExplorerPanel = ({ height }) => {
             setComputerPath('root');
             setComputerFiles([]);
             await browseComputerDir(rootEntry);
+          } else {
+            window.showToast && window.showToast('Không có quyền truy cập thư mục này', 'warning');
+          }
         } else {
           window.showToast && window.showToast('Không thể khôi phục quyền truy cập thư mục này', 'error');
         }
@@ -9803,7 +10023,7 @@ const MediaExplorerPanel = ({ height }) => {
     ctx.scale(2, 2);
     ctx.clearRect(0, 0, w, h);
     ctx.fillStyle = '#181818'; ctx.fillRect(0, 0, w, h);
-    // Read from refs so the rAF clock's stale closure still draws the latest file
+    
     const f = selectedRef.current;
     const curPeaks = peaksRef.current;
     const curAudioBuffer = audioBufferRef.current;
@@ -9819,32 +10039,35 @@ const MediaExplorerPanel = ({ height }) => {
       return;
     }
     const dur = fileDuration(f);
+    
+    // Scale layout parameters using zoom
+    const pxPerBeat = 42 * zoom;
+    const pxPerSec = pxPerBeat * (curTempo || 120) / 60;
+    
     if (isMidiFile(f)) {
       ctx.strokeStyle = '#333';
       for (let y = 0; y < h - 14; y += 10) { ctx.beginPath(); ctx.moveTo(0, y); ctx.lineTo(w, y); ctx.stroke(); }
       ctx.strokeStyle = '#444';
-      // Content scrolls when wider than frame: playhead stays at frame center
-      const bpmV = curTempo || 120;
-      const pxPerBeat = 42;
-      const totalBeats = (curMidiNotes && curMidiNotes.length && curMidiTotalBeats > 0)
-        ? curMidiTotalBeats
-        : Math.max(curMidiTotal * bpmV / 60, 4);
+      
+      const isRealMidi = curMidiNotes && curMidiNotes.length && curMidiTotalBeats > 0;
+      const totalBeats = isRealMidi ? curMidiTotalBeats : Math.max(curMidiTotal * (curTempo || 120) / 60, 4);
       const beats = Math.max(totalBeats, 4);
       const contentW = Math.max(w, beats * pxPerBeat);
-      const pxPerSec = pxPerBeat * bpmV / 60;
+      
       let offset = 0;
       if (playing && contentW > w && dur > 0) {
         offset = Math.max(0, Math.min(contentW - w, t * pxPerSec - w / 2));
       }
-      // bar lines (every 4 beats) + beat labels
+      
+      // bar lines (every 4 beats)
       for (let b = 0; b <= beats; b += 4) {
         const x = b * pxPerBeat - offset;
         if (x < -10 || x > w + 10) continue;
         ctx.beginPath(); ctx.moveTo(x, 0); ctx.lineTo(x, h - 14); ctx.stroke();
       }
+      
       ctx.fillStyle = '#9ca3af';
       if (curMidiNotes && curMidiNotes.length) {
-        // Real piano-roll: rows = pitches (48..84), columns = beats
         const pitchMin = 48, pitchMax = 84;
         const pitchRange = Math.max(1, pitchMax - pitchMin);
         curMidiNotes.forEach(n => {
@@ -9862,8 +10085,23 @@ const MediaExplorerPanel = ({ height }) => {
           ctx.fillRect(nx, ny, Math.max(8, (i % 5 + 1) * 10), 3);
         }
       }
-      // playhead (drawn over MIDI): moves to frame center, then stops there & content scrolls.
-      // Khi content không scroll được nữa (offset đạt max) thì playhead tiếp tục chạy tới cuối canvas.
+      
+      // Draw selection overlay
+      if (selStart !== null && selEnd !== null && Math.abs(selStart - selEnd) > 0.01) {
+        const startVal = Math.min(selStart, selEnd);
+        const endVal = Math.max(selStart, selEnd);
+        const xStart = startVal * pxPerBeat - offset;
+        const xEnd = endVal * pxPerBeat - offset;
+        ctx.fillStyle = 'rgba(59, 130, 246, 0.25)';
+        ctx.fillRect(xStart, 0, xEnd - xStart, h - 14);
+        ctx.strokeStyle = '#3b82f6';
+        ctx.lineWidth = 1;
+        ctx.beginPath();
+        ctx.moveTo(xStart, 0); ctx.lineTo(xStart, h - 14);
+        ctx.moveTo(xEnd, 0); ctx.lineTo(xEnd, h - 14);
+        ctx.stroke();
+      }
+      
       const midiPlayheadX = contentW > w ? Math.max(0, Math.min(w, t * pxPerSec - offset)) : Math.min(w, t * pxPerSec);
       if (playing && dur > 0) {
         ctx.fillStyle = '#ef4444';
@@ -9872,10 +10110,6 @@ const MediaExplorerPanel = ({ height }) => {
     } else {
       const pk = curPeaks && curPeaks.length > 0 ? curPeaks : null;
       if (pk) {
-        // Audio hiển thị theo tỉ lệ tempo (pxPerSec), không giãn đầy khung preview
-        const audioBpm = curTempo || 120;
-        const pxPerBeat = 42;
-        const pxPerSec = pxPerBeat * audioBpm / 60;
         const contentW = Math.max(1, dur * pxPerSec);
         let offset = 0;
         if (playing && contentW > w && dur > 0) {
@@ -9890,8 +10124,23 @@ const MediaExplorerPanel = ({ height }) => {
           const ph = Math.max(2, pk[i] * (h / 2 - 4));
           ctx.fillRect(x, mid - ph, barW, ph * 2);
         }
-        // Playhead theo tỉ lệ tempo; khi content rộng hơn frame thì khóa giữa + scroll.
-        // Khi content không scroll được nữa (offset đạt max) thì playhead tiếp tục chạy tới cuối canvas.
+        
+        // Draw selection overlay
+        if (selStart !== null && selEnd !== null && Math.abs(selStart - selEnd) > 0.01) {
+          const startVal = Math.min(selStart, selEnd);
+          const endVal = Math.max(selStart, selEnd);
+          const xStart = startVal * pxPerSec - offset;
+          const xEnd = endVal * pxPerSec - offset;
+          ctx.fillStyle = 'rgba(59, 130, 246, 0.25)';
+          ctx.fillRect(xStart, 0, xEnd - xStart, h - 14);
+          ctx.strokeStyle = '#3b82f6';
+          ctx.lineWidth = 1;
+          ctx.beginPath();
+          ctx.moveTo(xStart, 0); ctx.lineTo(xStart, h - 14);
+          ctx.moveTo(xEnd, 0); ctx.lineTo(xEnd, h - 14);
+          ctx.stroke();
+        }
+        
         const audioPlayheadX = contentW > w ? Math.max(0, Math.min(w, t * pxPerSec - offset)) : (t * pxPerSec);
         if (playing && dur > 0) {
           ctx.fillStyle = '#ef4444';
@@ -9902,25 +10151,22 @@ const MediaExplorerPanel = ({ height }) => {
         ctx.fillText('Waveform unavailable', 10, h / 2);
       }
     }
+    
     // ruler
     ctx.fillStyle = '#111'; ctx.fillRect(0, h - 14, w, 14);
     ctx.fillStyle = '#888'; ctx.font = '9px JetBrains Mono, monospace';
-    const rulerBpm = curTempo || 120;
-    const rulerPxPerBeat = 42;
     const isRealMidi = isMidiFile(f) && curMidiNotes && curMidiNotes.length && curMidiTotalBeats > 0;
-    const rulerTotalBeats = isRealMidi ? Math.max(curMidiTotalBeats, 4) : Math.max(4, Math.ceil(dur * rulerBpm / 60) || 16);
-    // Tỉ lệ theo tempo (không giãn đầy khung)
-    const rulerContentW = Math.max(1, rulerTotalBeats * rulerPxPerBeat);
-    const rulerPxPerSec = rulerPxPerBeat * rulerBpm / 60;
-    const rulerOffset = (playing && rulerContentW > w && dur > 0) ? Math.max(0, Math.min(rulerContentW - w, t * rulerPxPerSec - w / 2)) : 0;
+    const rulerTotalBeats = isRealMidi ? Math.max(curMidiTotalBeats, 4) : Math.max(4, Math.ceil(dur * (curTempo || 120) / 60) || 16);
+    const rulerContentW = Math.max(1, rulerTotalBeats * pxPerBeat);
+    const rulerOffset = (playing && rulerContentW > w && dur > 0) ? Math.max(0, Math.min(rulerContentW - w, t * pxPerSec - w / 2)) : 0;
     for (let b = 0; b <= rulerTotalBeats; b += 4) {
-      const x = b * rulerPxPerBeat - rulerOffset;
+      const x = b * pxPerBeat - rulerOffset;
       if (x < -20 || x > w + 20) continue;
       ctx.fillText(String(Math.floor(b / 4)), x + 2, h - 3);
     }
   };
 
-  React.useEffect(() => { drawCanvas(currentTime); }, [peaks, audioBuffer, audioDuration, midiNotes, selected, folder, isPlaying]);
+  React.useEffect(() => { drawCanvas(currentTime); }, [peaks, audioBuffer, audioDuration, midiNotes, selected, folder, isPlaying, zoom, selStart, selEnd]);
   React.useEffect(() => () => { if (rafRef.current) cancelAnimationFrame(rafRef.current); }, []);
 
   const handleSelect = (f) => {
@@ -9933,6 +10179,9 @@ const MediaExplorerPanel = ({ height }) => {
     setAudioBuffer(null);
     setAudioDuration(0);
     setMidiNotes(null);
+    setSelStart(null);
+    setSelEnd(null);
+    setPreviewCtxMenu(null);
     stopMediaPlayback();
     if (f.kind === 'other') return;
     if (autoPlay) { playSelected(f, token); }
@@ -10030,25 +10279,17 @@ const MediaExplorerPanel = ({ height }) => {
             <div className="space-y-0.5 font-sans">
             <div className="flex items-center gap-1 px-1 py-0.5 text-slate-700"><span className="w-3"></span> &lt;Track Templates&gt;</div>
             <div className="flex items-center gap-1 px-1 py-0.5 text-slate-700"><span className="w-3"></span> &lt;Project Directory&gt;</div>
-            <div className={`flex items-center gap-1 px-1 py-0.5 cursor-pointer rounded-sm ${folder === 'computer' && computerPath !== 'favorited' ? 'bg-slate-300 text-slate-900 font-semibold' : 'hover:bg-slate-200 text-slate-800'}`} onClick={openMyComputer}>
-              <i className="fa-solid fa-computer text-[11px] text-slate-600"></i> My Computer
-            </div>
-            {folder === 'computer' && computerPath !== 'favorited' && computerRoots && (
-              <div className="pl-3 space-y-0.5">
-                {computerRoots.map(root => renderComputerNode(root, 0, true))}
-              </div>
-            )}
-
-            <div className={`flex items-center gap-1 px-1 py-0.5 cursor-pointer rounded-sm ${folder === 'computer' && computerPath === 'favorited' ? 'bg-slate-300 text-slate-900 font-semibold' : 'hover:bg-slate-200 text-slate-800'}`} onClick={openFavorited}>
-              <i className={`fa-solid ${favoritedExpanded ? 'fa-minus' : 'fa-plus'} text-[9px] text-slate-500 w-3 text-center shrink-0`} onClick={e => { e.stopPropagation(); setFavoritedExpanded(!favoritedExpanded); }}></i>
-              <i className="fa-solid fa-star text-amber-500 text-[10px]"></i> Favorited
+            {/* FAVORITED */}
+            <div className={`flex items-center gap-1 px-1 py-0.5 cursor-pointer rounded-sm font-bold ${folder === 'computer' && computerPath === 'favorited' ? 'bg-slate-300 text-slate-900' : 'hover:bg-slate-200 text-slate-800'}`} 
+              onClick={() => { openFavorited(); setFavoritedExpanded(!favoritedExpanded); }}>
+              <i className="fa-solid fa-star text-amber-500 text-[11px] font-bold"></i> Favorited
             </div>
             {favoritedExpanded && (
               <div className="pl-3 space-y-0.5">
                 {favorites.map((fav, fi) => (
                   <div key={fav.path + fi}
-                    className="flex items-center gap-1 px-1 py-0.5 cursor-pointer pl-4 rounded-sm hover:bg-amber-100 text-slate-800"
-                    style={{ paddingLeft: 24 }}
+                    className="flex items-center gap-1 px-1 py-0.5 cursor-pointer rounded-sm hover:bg-amber-100 text-slate-800"
+                    style={{ paddingLeft: 20 }}
                     onClick={() => openFavorite(fav)}
                     onContextMenu={e => { e.preventDefault(); e.stopPropagation(); setFavContext(Object.assign({}, fav, { x: e.clientX, y: e.clientY })); }}>
                     <i className="fa-solid fa-folder text-[#d9a752] shrink-0"></i>
@@ -10062,6 +10303,16 @@ const MediaExplorerPanel = ({ height }) => {
               </div>
             )}
 
+            {/* MY COMPUTER */}
+            <div className={`flex items-center gap-1 px-1 py-0.5 cursor-pointer rounded-sm ${folder === 'computer' && computerPath !== 'favorited' ? 'bg-slate-300 text-slate-900 font-semibold' : 'hover:bg-slate-200 text-slate-800'}`} onClick={openMyComputer}>
+              <i className="fa-solid fa-computer text-[11px] text-slate-600"></i> My Computer
+            </div>
+            {folder === 'computer' && computerPath !== 'favorited' && computerRoots && (
+              <div className="pl-3 space-y-0.5">
+                {computerRoots.map(root => renderComputerNode(root, 0, true))}
+              </div>
+            )}
+
             <div className={`flex items-center gap-1 px-1 py-0.5 cursor-pointer font-semibold rounded-sm ${folder === 'library' ? 'bg-slate-300 text-slate-900' : 'hover:bg-slate-200 text-slate-800'}`} onClick={() => setFolder('library')}>
               <i className="fa-solid fa-folder-open text-[#d9a752]"></i> Media Library
             </div>
@@ -10251,7 +10502,65 @@ const MediaExplorerPanel = ({ height }) => {
         {/* CANVAS + METADATA */}
         <div className="flex items-stretch gap-2 my-1 flex-1 min-h-0">
           <div className="flex-1 bg-[#181818] border border-[#3a3a3a] relative overflow-hidden">
-            <canvas ref={canvasRef} className="w-full h-full block cursor-pointer"></canvas>
+            <canvas 
+              ref={canvasRef} 
+              className="w-full h-full block cursor-pointer"
+              onMouseDown={handleCanvasMouseDown}
+              onMouseMove={handleCanvasMouseMove}
+              onMouseUp={handleCanvasMouseUp}
+              onContextMenu={handleCanvasContextMenu}
+              onWheel={handleCanvasWheel}
+            ></canvas>
+            
+            {/* FLOATING ZOOM CONTROLS */}
+            <div className="absolute top-1.5 right-1.5 flex gap-1 z-10">
+              <button 
+                className="w-5 h-5 bg-[#2a2a2a] hover:bg-slate-700 border border-[#444] rounded flex items-center justify-center text-white text-xs font-bold select-none cursor-pointer" 
+                title="Zoom In" 
+                onClick={() => setZoom(prev => Math.min(10.0, prev * 1.25))}
+              >
+                +
+              </button>
+              <button 
+                className="w-5 h-5 bg-[#2a2a2a] hover:bg-slate-700 border border-[#444] rounded flex items-center justify-center text-white text-xs font-bold select-none cursor-pointer" 
+                title="Zoom Out" 
+                onClick={() => setZoom(prev => Math.max(0.2, prev / 1.25))}
+              >
+                -
+              </button>
+              <button 
+                className="w-5 h-5 bg-[#2a2a2a] hover:bg-slate-700 border border-[#444] rounded flex items-center justify-center text-white text-[9px] select-none cursor-pointer" 
+                title="Reset Zoom" 
+                onClick={() => setZoom(1.0)}
+              >
+                1x
+              </button>
+            </div>
+
+            {/* PREVIEW CONTEXT MENU */}
+            {previewCtxMenu && (
+              <div 
+                className="fixed bg-[#1e1e24] border border-[#3e3e4a] rounded shadow-md z-[9999] py-1 font-sans text-xs text-slate-300 w-32 cursor-pointer select-none"
+                style={{ top: previewCtxMenu.y, left: previewCtxMenu.x }}
+                onClick={(e) => e.stopPropagation()}
+              >
+                <div 
+                  className="px-3 py-1.5 hover:bg-slate-700 hover:text-white flex items-center gap-2"
+                  onClick={() => {
+                    handleCopySelection();
+                    setPreviewCtxMenu(null);
+                  }}
+                >
+                  <i className="fa-solid fa-copy"></i> Copy
+                </div>
+                <div 
+                  className="px-3 py-1.5 hover:bg-slate-700 hover:text-white border-t border-[#3e3e4a] flex items-center gap-2"
+                  onClick={() => setPreviewCtxMenu(null)}
+                >
+                  <i className="fa-solid fa-xmark"></i> Cancel
+                </div>
+              </div>
+            )}
           </div>
           <div className="w-48 bg-[#181818] border border-[#3a3a3a] p-1.5 font-mono text-[10px] text-slate-300 leading-tight overflow-y-auto shrink-0">
             {selected ? (
@@ -12176,13 +12485,43 @@ const App = () => {
   };
   const handleSubTabPaste = tabId => {
     const st = subTabsRef.current.find(s => s.id === tabId);
-    if (!st || !st.buffer) return;
-    if (!clipboardRef.current || !clipboardRef.current.buffer) {
-      showToast('Clipboard trống.', 'warning');
+    if (!st) return;
+
+    // Check if Piano Roll Tab
+    if (st.type === 'PIANO_ROLL') {
+      const clip = clipboardRef.current || window.globalStudioClipboard;
+      if (!clip || clip.type !== 'midi' || !clip.notes) {
+        showToast('Clipboard không chứa dữ liệu MIDI.', 'warning');
+        return;
+      }
+      const secondsPerBeat = 60 / (bpm || 120);
+      const pasteBeat = (st.currentTime || 0) / secondsPerBeat;
+      
+      const newNotes = clip.notes.map(n => ({
+        id: 'note_' + Math.random().toString(36).substr(2, 9),
+        pitch: n.pitch,
+        start_beat: pasteBeat + n.start_beat,
+        duration_beats: n.duration_beats,
+        velocity: n.velocity || 0.8
+      }));
+      
+      setSubTabs(prev => prev.map(s => s.id === tabId ? {
+        ...s,
+        notes: [...(s.notes || []), ...newNotes]
+      } : s));
+      showToast('Đã dán note MIDI vào Piano Roll.', 'success');
+      return;
+    }
+
+    // Default Waveform Audio Paste
+    if (!st.buffer) return;
+    const clip = clipboardRef.current || window.globalStudioClipboard;
+    if (!clip || !clip.buffer) {
+      showToast('Clipboard trống hoặc không chứa dữ liệu âm thanh.', 'warning');
       return;
     }
     const ctx = getAudioContext();
-    const clipBuf = clipboardRef.current.buffer;
+    const clipBuf = clip.buffer;
     const sr = st.buffer.sampleRate;
     const data = st.buffer.getChannelData(0);
     const insertTime = st.currentTime || 0;
@@ -13730,10 +14069,74 @@ const App = () => {
     contextMenuDelete();
   };
   const doPaste = (targetTrackId, pasteTime) => {
-    if (!clipboardRef.current || !clipboardRef.current.buffer) {
+    const clip = clipboardRef.current || window.globalStudioClipboard;
+    if (!clip) {
       showToast('Clipboard trống.', 'warning');
       return null;
     }
+    
+    // Support MIDI Clip Paste
+    if (clip.type === 'midi') {
+      const { notes, name, duration, color } = clip;
+      const targetTrack = activeTracks.find(t => t.id === targetTrackId);
+      const newMidiItem = {
+        id: 'midi_' + Date.now(),
+        startTime: pasteTime,
+        duration: duration || 4,
+        name: (name || 'Pasted MIDI').replace(/\.\w+$/, '') + ' (Pasted)',
+        notes: notes.map(n => ({
+          id: 'note_' + Math.random().toString(36).substr(2, 9),
+          pitch: n.pitch,
+          start_beat: n.start_beat,
+          duration_beats: n.duration_beats,
+          velocity: n.velocity || 0.8
+        }))
+      };
+      
+      if (targetTrack) {
+        updateActiveTracks(p => p.map(t => {
+          if (t.id === targetTrackId) {
+            const existingMidi = t.midiItems || [];
+            return {
+              ...t,
+              midiItems: [...existingMidi, newMidiItem]
+            };
+          }
+          return t;
+        }));
+        setCurrentTime(pasteTime);
+        showToast('Đã dán MIDI vào track.', 'success');
+        return targetTrackId;
+      } else {
+        const colors = ['#0f766e', '#1d4ed8', '#701a75', '#a21caf', '#b45309'];
+        const rearrangeNewId = 'track_pasted_midi_' + Date.now();
+        updateActiveTracks(prev => [...prev, {
+          id: rearrangeNewId,
+          name: `Pasted_${name || 'MIDI'}`,
+          buffer: null,
+          startTime: 0,
+          clips: [],
+          midiItems: [newMidiItem],
+          volumeDb: 0,
+          pan: 0,
+          muted: false,
+          solo: false,
+          color: color || colors[prev.length % colors.length],
+          markers: [],
+          serverFileId: null
+        }]);
+        setSelectedTrackId(rearrangeNewId);
+        setCurrentTime(pasteTime);
+        showToast('Đã dán track MIDI mới từ clipboard.', 'success');
+        return rearrangeNewId;
+      }
+    }
+    
+    // Default Audio Clip Paste
+    if (!clip.buffer) {
+      showToast('Clipboard không chứa dữ liệu âm thanh hợp lệ.', 'warning');
+      return null;
+    }
     const {
       buffer: clipBuffer,
       name,
@@ -13743,7 +14146,7 @@ const App = () => {
       sampleRate,
       channels,
       speed
-    } = clipboardRef.current;
+    } = clip;
     const ctx = getAudioContext();
     const targetTrack = activeTracks.find(t => t.id === targetTrackId);
     const newClip = {
@@ -22664,7 +23067,8 @@ const App = () => {
     })))), /*#__PURE__*/React.createElement("div", {
       className: "flex-1 min-h-0 overflow-hidden bg-[#262626]"
     }, /*#__PURE__*/React.createElement(MediaExplorerPanel, {
-      height: mediaExplorerPanelHeight
+      height: mediaExplorerPanelHeight,
+      clipboardRef: clipboardRef
     }))));
   })(), /*#__PURE__*/React.createElement("div", {
     className: "h-6 bg-[#141414] border-t border-zinc-900 px-4 flex items-center justify-between text-xs text-zinc-500 select-none shrink-0"