# 09. Image Caching & Coil Optimization

meta:
  id: android-production-09
  feature: android-production
  priority: P2
  depends_on: []
  tags: [performance, caching, production]

objective:
- Optimize Coil image caching and loading for better performance and reduced network usage

deliverables:
- Coil cache configuration
- Image loading optimization
- Lazy loading for lists
- Memory and disk cache limits

steps:
1. Configure Coil:
   - Set up ImageLoader in KordantApp.kt
   - Configure memory cache (50MB)
   - Configure disk cache (100MB)
   - Set crossfade animation
   - Configure placeholder and error drawables
2. Optimize image loading:
   - Use appropriate image sizes (thumbnail vs full)
   - Enable image transformations (circle crop for avatars)
   - Use WebP format where supported
   - Configure request priorities
3. Implement lazy loading:
   - Use LazyColumn for all lists
   - Implement pagination for long lists
   - Add prefetching for adjacent items
   - Show skeleton placeholders while loading
4. Add offline support:
   - Cache images for offline viewing
   - Show cached images when offline
   - Handle network errors gracefully
5. Optimize memory usage:
   - Clear memory cache on low memory
   - Limit concurrent image loads
   - Cancel loads for off-screen items
6. Add tests:
   - Test cache hit/miss behavior
   - Test scrolling performance with many images

tests:
- Unit: Test cache configuration
- Performance: Test scrolling with 1000 images
- Memory: Verify no memory leaks

acceptance_criteria:
- Coil ImageLoader configured with 50MB memory / 100MB disk cache
- Lazy loading on all lists with pagination
- Image placeholders while loading
- Error state for failed loads
- Cache cleared on low memory
- Offline image viewing working
- Smooth 60fps scrolling on image-heavy screens
- No memory leaks in image loading
- Crossfade animation on image load
- Appropriate image sizes requested from backend

validation:
- Scroll through alert list → smooth, no stuttering
- Turn on airplane mode → cached images still visible
- Monitor memory → stable during image browsing
- Check cache directory → images stored with correct expiration

notes:
- Coil is already included in dependencies (libs.coil.compose)
- Configuration happens in Application class
- Use rememberAsyncImagePainter for Compose integration
- Test on low-end devices for performance validation