// 1. React DevTools Profiler
// - Record a session
// - Look for long render times (> 16ms = frame drop)
// - Identify components rendering too often

// 2. Why Did You Render (development)
// npm install @welldone-software/why-did-you-render
import whyDidYouRender from '@welldone-software/why-did-you-render';
whyDidYouRender(React, { trackAllPureComponents: true });

// 3. Manual timing
console.time('[Render] MyComponent');
// ... render ...
console.timeEnd('[Render] MyComponent');

// 1. Memoize components
const MyComponent = React.memo(({ data }) => {
  return <div>{data.name}</div>;
});

// 2. Memoize expensive computations
const processedData = useMemo(() => {
  return expensiveProcessing(rawData);
}, [rawData]); // Only recalculate when rawData changes

// 3. Memoize callbacks
const handleClick = useCallback((id: string) => {
  doSomething(id);
}, []); // Stable reference

// 4. Use Zustand selectors properly
// BAD - re-renders on ANY store change
const state = useCanvasStore();

// GOOD - only re-renders when widgets change
const widgets = useCanvasStore((s) => s.widgets);

// BETTER - shallow compare for objects
import { shallow } from 'zustand/shallow';
const { widgets, selection } = useCanvasStore(
  (s) => ({ widgets: s.widgets, selection: s.selection }),
  shallow
);

import { FixedSizeList } from 'react-window';

// Instead of rendering all items:
// widgets.map((widget) => <WidgetCard widget={widget} />)

// Use virtualization:
<FixedSizeList
  height={600}
  width={300}
  itemCount={widgets.length}
  itemSize={80}
>
  {({ index, style }) => (
    <div style={style}>
      <WidgetCard widget={widgets[index]} />
    </div>
  )}
</FixedSizeList>

// Lazy load heavy components
const HeavyEditor = React.lazy(() => import('./HeavyEditor'));

// Use with Suspense
<Suspense fallback={<LoadingSpinner />}>
  <HeavyEditor />
</Suspense>

// Route-level lazy loading
const CanvasPage = React.lazy(() => import('./pages/CanvasPage'));

import { useFrame } from '@react-three/fiber';
import { useRef } from 'react';

function FPSMonitor() {
  const frames = useRef(0);
  const lastTime = useRef(performance.now());

  useFrame(() => {
    frames.current++;
    const now = performance.now();
    if (now - lastTime.current >= 1000) {
      console.log('[FPS]', frames.current);
      frames.current = 0;
      lastTime.current = now;
    }
  });

  return null;
}

// 1. Reuse geometries
const sharedGeometry = useMemo(() => new THREE.PlaneGeometry(1, 1), []);

// 2. Instanced meshes for many identical objects
import { Instances, Instance } from '@react-three/drei';

<Instances limit={1000} geometry={sharedGeometry} material={sharedMaterial}>
  {positions.map((pos, i) => (
    <Instance key={i} position={pos} />
  ))}
</Instances>

// 3. Merge static geometries
import { mergeGeometries } from 'three/examples/jsm/utils/BufferGeometryUtils';

// 1. Reuse materials
const sharedMaterial = useMemo(
  () => new THREE.MeshStandardMaterial({ color: '#1e1b4b' }),
  []
);

// 2. Use simpler materials when possible
<meshBasicMaterial />      // Fastest - no lighting
<meshLambertMaterial />    // Fast - simple lighting
<meshStandardMaterial />   // Medium - PBR
<meshPhysicalMaterial />   // Slow - full PBR

// 3. Disable features you don't need
<meshStandardMaterial
  flatShading        // Skip normal interpolation
  dithering={false}  // Skip dithering
/>

// 1. Frustum culling (enabled by default)
<mesh frustumCulled={true}>

// 2. Level of Detail
import { LOD } from 'three';

const lod = new LOD();
lod.addLevel(highDetailMesh, 0);    // Use when close
lod.addLevel(mediumDetailMesh, 50); // Use at 50 units
lod.addLevel(lowDetailMesh, 100);   // Use at 100 units

// 3. Distance-based rendering
const distance = camera.position.distanceTo(object.position);
if (distance > 100) return null; // Don't render far objects

// 1. Target 72fps minimum (Quest), 90fps (PC VR)
// Frame budget: ~14ms for 72fps, ~11ms for 90fps

// 2. Reduce draw calls
// - Batch similar materials
// - Use instancing
// - Merge static geometry

// 3. Foveated rendering (if supported)
// The center of view renders at full res, edges at lower res

// 4. Reduce Html components
// Each <Html> creates DOM overlay - expensive in XR
// Use <Text> from drei instead for labels

# Generate bundle analysis
npm run build -- --analyze

# Or use source-map-explorer
npx source-map-explorer dist/assets/*.js

// 1. Route-based splitting (automatic with lazy)
const routes = [
  { path: '/', element: lazy(() => import('./pages/Home')) },
  { path: '/canvas', element: lazy(() => import('./pages/Canvas')) },
];

// 2. Feature-based splitting
const loadAIFeatures = () => import('./features/ai');

// 3. Vendor chunking (vite.config.ts)
build: {
  rollupOptions: {
    output: {
      manualChunks: {
        'vendor-react': ['react', 'react-dom'],
        'vendor-three': ['three', '@react-three/fiber', '@react-three/drei'],
        'vendor-ui': ['@radix-ui/react-dialog', '@radix-ui/react-dropdown-menu'],
      },
    },
  },
}

// BAD - imports entire library
import _ from 'lodash';
_.debounce(fn, 100);

// GOOD - imports only what's needed
import debounce from 'lodash/debounce';
debounce(fn, 100);

// Also check for side-effect imports
import 'heavy-library'; // Might not tree-shake

// 1. Chrome DevTools Memory tab
// - Take heap snapshots before/after operations
// - Compare to find retained objects

// 2. Common leak sources:
// - Event listeners not removed
// - setInterval/setTimeout not cleared
// - Subscriptions not unsubscribed
// - Closures holding references

// 3. Cleanup pattern
useEffect(() => {
  const handler = () => { /* ... */ };
  window.addEventListener('resize', handler);

  const interval = setInterval(() => { /* ... */ }, 1000);

  const subscription = store.subscribe(() => { /* ... */ });

  return () => {
    window.removeEventListener('resize', handler);
    clearInterval(interval);
    subscription(); // Unsubscribe
  };
}, []);

// Dispose geometries and materials when done
useEffect(() => {
  return () => {
    geometry.dispose();
    material.dispose();
    texture?.dispose();
  };
}, []);

// For dynamic scenes, track and dispose
const disposables = useRef<THREE.Object3D[]>([]);

function addObject(obj: THREE.Object3D) {
  scene.add(obj);
  disposables.current.push(obj);
}

function cleanup() {
  disposables.current.forEach((obj) => {
    scene.remove(obj);
    if (obj instanceof THREE.Mesh) {
      obj.geometry.dispose();
      (obj.material as THREE.Material).dispose();
    }
  });
  disposables.current = [];
}