# Product Requirements Document: Auto-Save Functionality

## Executive Summary
Implement an intelligent auto-save system for all admin forms and editors to prevent data loss and improve the content creation experience.

## Problem Statement
Currently, users must manually save their work in the admin interface, which can lead to:
- Data loss if the browser crashes or connection is interrupted
- Anxiety about losing work during long editing sessions
- Inefficient workflow with frequent manual saves
- No recovery mechanism for unsaved changes

## Goals & Success Metrics

### Primary Goals
1. Prevent data loss during content creation
2. Provide seamless, unobtrusive saving experience
3. Enable recovery from unexpected interruptions
4. Maintain data consistency and integrity

### Success Metrics
- 0% data loss from browser crashes or network issues
- <3 second save latency for typical content
- 95% of saves complete without user intervention
- User satisfaction with editing experience improvement

## User Stories

### As a content creator
- I want my work to be automatically saved so I don't lose progress
- I want to see clear feedback about save status
- I want to recover my work if something goes wrong
- I want control over when auto-save is active

### As a site administrator
- I want to ensure data integrity across all saves
- I want to minimize server load from frequent saves
- I want to track save patterns for optimization

## Functional Requirements

### Core Auto-Save System

#### 1. Smart Debouncing
- **Content changes**: 2-second delay after user stops typing
- **Metadata changes**: Immediate save for critical fields
- **Navigation events**: Immediate save before leaving page
- **Keyboard shortcut**: Cmd/Ctrl+S for manual save

#### 2. Save States & Feedback
- **Idle**: No pending changes
- **Saving**: Active save in progress with spinner
- **Saved**: Confirmation with timestamp
- **Error**: Clear error message with retry option
- **Conflict**: Detection and resolution UI

#### 3. Data Persistence
- **Server-first**: Primary storage in database
- **Local backup**: IndexedDB for offline/recovery
- **Conflict detection**: Version tracking with timestamps
- **Partial saves**: Only send changed fields

### Visual Design

#### Status Indicator
```
States:
- Idle: No indicator (clean UI)
- Saving: "Saving..." with subtle spinner
- Saved: "All changes saved" (fades after 2s)
- Error: Red indicator with retry button
- Offline: "Working offline" badge
```

#### Positioning
- Fixed position in editor header
- Non-intrusive, doesn't shift content
- Responsive to different screen sizes
- Accessible color contrast

### API Design

#### New Endpoints
```typescript
// Auto-save endpoint
POST /api/posts/[id]/autosave
Body: {
  content?: JSONContent,
  title?: string,
  metadata?: object,
  lastModified: timestamp
}
Response: {
  success: boolean,
  lastModified: timestamp,
  conflict?: {
    serverVersion: object,
    serverModified: timestamp
  }
}

// Recovery endpoint  
GET /api/posts/[id]/recover
Response: {
  localDraft?: object,
  serverVersion: object,
  timestamps: {
    local?: timestamp,
    server: timestamp
  }
}
```

### Integration Points

#### Form Components to Update
1. **EssayForm.svelte** - Blog posts and essays
2. **ProjectForm.svelte** - Project case studies
3. **AlbumForm.svelte** - Album descriptions
4. **SimplePostForm.svelte** - Simple text posts
5. **PhotoPostForm.svelte** - Photo posts with captions

#### Composer Integration
- Hook into TipTap editor's `onUpdate` event
- Track content changes separately from metadata
- Handle rich media embeds appropriately

## Technical Requirements

### Frontend Architecture

#### Auto-Save Hook (`useAutoSave.svelte.ts`)
```typescript
class AutoSave {
  private state = $state<'idle' | 'saving' | 'saved' | 'error'>('idle')
  private lastSaved = $state<Date | null>(null)
  private saveTimer: NodeJS.Timeout | null = null
  private saveQueue: Set<string> = new Set()
  
  constructor(options: AutoSaveOptions) {
    // Initialize with endpoint, auth, debounce settings
  }
  
  track(field: string, value: any): void
  save(immediate?: boolean): Promise<void>
  recover(): Promise<RecoveryData>
  reset(): void
}
```

#### Svelte 5 Integration
- Use `$state` rune for reactive state
- Use `$effect` for side effects and cleanup
- Use `$derived` for computed values
- Maintain compatibility with existing stores

### Backend Requirements

#### Database Schema Updates
```sql
-- Add version tracking
ALTER TABLE posts ADD COLUMN version INTEGER DEFAULT 1;
ALTER TABLE posts ADD COLUMN last_auto_save TIMESTAMP;

-- Auto-save drafts table
CREATE TABLE auto_save_drafts (
  id SERIAL PRIMARY KEY,
  entity_type VARCHAR(50),
  entity_id INTEGER,
  user_id INTEGER,
  content JSONB,
  created_at TIMESTAMP DEFAULT NOW()
);
```

#### Performance Optimizations
- Implement request coalescing for rapid changes
- Use database transactions for consistency
- Add Redis caching for conflict detection
- Implement rate limiting per user

### Security Considerations
- Validate user ownership before auto-save
- Sanitize content to prevent XSS
- Rate limit to prevent abuse
- Encrypt local storage data
- Audit trail for all saves

## Non-Functional Requirements

### Performance
- Save latency <500ms for text content
- <2MB memory overhead per form
- Debounce efficiency >90% reduction in requests
- Support 100+ concurrent editors

### Reliability
- 99.9% save success rate
- Graceful degradation on network issues
- Automatic retry with exponential backoff
- Data recovery from last 24 hours

### Usability
- Zero configuration for basic use
- Clear, non-technical error messages
- Intuitive conflict resolution
- Keyboard accessible

### Compatibility
- Chrome 90+, Firefox 88+, Safari 14+
- Mobile responsive
- Works with screen readers
- Progressive enhancement

## Implementation Plan

### Phase 1: Core Infrastructure (Week 1-2)
- [ ] Create `useAutoSave` hook
- [ ] Implement debouncing logic
- [ ] Add basic status component
- [ ] Create auto-save API endpoint

### Phase 2: Form Integration (Week 2-3)
- [ ] Integrate with EssayForm
- [ ] Integrate with ProjectForm
- [ ] Add keyboard shortcuts
- [ ] Implement local storage backup

### Phase 3: Advanced Features (Week 3-4)
- [ ] Conflict detection and resolution
- [ ] Offline support with service worker
- [ ] Recovery interface
- [ ] Performance monitoring

### Phase 4: Polish & Testing (Week 4-5)
- [ ] UI/UX refinements
- [ ] Comprehensive testing
- [ ] Documentation
- [ ] Performance optimization

## Testing Strategy

### Unit Tests
- Debounce logic validation
- State management correctness
- API error handling
- Local storage operations

### Integration Tests
- Form component integration
- API endpoint validation
- Conflict resolution flow
- Recovery scenarios

### E2E Tests
- Complete save flow
- Network interruption handling
- Multi-tab scenarios
- Mobile experience

### Performance Tests
- Load testing with concurrent users
- Memory leak detection
- Network bandwidth usage
- Database query optimization

## Rollout Strategy

1. **Beta Testing**: Deploy to staging with select users
2. **Gradual Rollout**: Enable for 10% → 50% → 100% of forms
3. **Monitoring**: Track save success rates and user feedback
4. **Iteration**: Refine based on real-world usage

## Future Enhancements

### Version 2.0
- Real-time collaboration indicators
- Revision history with diff view
- Auto-save templates and drafts
- AI-powered content suggestions

### Version 3.0
- Multi-device sync
- Offline-first architecture
- Advanced merge conflict resolution
- Team collaboration features

## Risks & Mitigations

| Risk | Impact | Mitigation |
|------|--------|------------|
| Data corruption | High | Implement checksums and validation |
| Performance degradation | Medium | Rate limiting and request batching |
| User confusion | Low | Clear UI feedback and documentation |
| Storage limits | Low | Implement cleanup and quotas |

## Dependencies

### External Libraries
- None required (uses native Svelte/SvelteKit features)

### Internal Systems
- Existing authentication system
- Toast notification system
- TipTap editor integration
- Prisma database client

## Acceptance Criteria

- [ ] Auto-save activates within 2 seconds of changes
- [ ] Visual feedback appears for all save states
- [ ] Manual save button remains functional
- [ ] Recovery works after browser crash
- [ ] No data loss in normal operation
- [ ] Performance metrics meet targets
- [ ] Accessibility standards met
- [ ] Documentation complete

## Appendix

### Competitive Analysis
- **Notion**: Instant save with "Saving..." indicator
- **Google Docs**: Real-time with conflict resolution
- **WordPress**: Auto-save drafts every 60 seconds
- **Medium**: Continuous save with version history

### User Research Insights
- Users expect auto-save in modern editors
- Visual feedback reduces anxiety
- Recovery options increase trust
- Performance is critical for user satisfaction

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**Document Version**: 1.0  
**Last Updated**: 2025-01-30  
**Author**: System Architecture Team  
**Status**: Ready for Implementation