updated TODO.md

Signed-off-by: Vimal Kumar <[email protected]>

docs/TODO.md

@@ -1,111 +1,209 @@
 # Crossword Puzzle Webapp - TODO List
 
-## Implementation Tasks
-
-### Phase 1: Project Setup
-- [ ] Set up project structure and initialize repositories
-  - Create frontend/ and backend/ directories
-  - Initialize package.json files
-  - Set up Git repository
-  - Configure ESLint and Prettier
-
-### Phase 2: Database & Data Management
-- [ ] Create database schema and seed data
-  - Design PostgreSQL tables (Topics, Words, Clues)
-  - Create migration scripts
-  - Seed database with initial word lists by topic
-  - Set up Prisma ORM configuration
-
-### Phase 3: Core Algorithm Development
-- [ ] Implement crossword generation algorithm
-  - Word selection logic based on topics
-  - Grid placement algorithm with intersections
-  - Backtracking for conflict resolution
-  - Grid optimization (minimize size, maximize density)
-
-### Phase 4: Backend API
-- [ ] Build backend API endpoints
-  - GET /topics - List available topics
-  - POST /generate - Generate crossword puzzle
-  - POST /validate - Validate user answers
-  - Error handling and validation middleware
-  - CORS configuration
-
-### Phase 5: Frontend Components
-- [ ] Create frontend components (TopicSelector, PuzzleGrid, ClueList)
-  - TopicSelector with multi-select functionality
-  - PuzzleGrid with CSS Grid layout
-  - ClueList component (Across/Down)
-  - LoadingSpinner for generation feedback
-  - PuzzleControls (Reset/New/Difficulty)
-
-### Phase 6: Interactive Features
-- [ ] Implement interactive crossword grid functionality
-  - Click-to-focus input cells
-  - Keyboard navigation (arrow keys, tab)
-  - Real-time input validation
-  - Highlight current word being filled
-  - Auto-advance to next cell
-
-### Phase 7: User Experience
-- [ ] Add puzzle validation and user input handling
-  - Check answers against solution
-  - Provide visual feedback (correct/incorrect)
-  - Show completion status
-  - Reset and new puzzle functionality
-
-### Phase 8: Styling & Polish
-- [ ] Style the application and improve UX
-  - Responsive design for mobile/desktop
-  - Professional color scheme
-  - Smooth animations and transitions
-  - Loading states and error messages
-  - Print-friendly styles
-
-### Phase 9: Environment Setup
-- [ ] Set up development and production environments
-  - Configure environment variables
-  - Set up local development database
-  - Configure build scripts
-  - Set up CI/CD pipeline with GitHub Actions
-
-### Phase 10: Deployment
-- [ ] Deploy application and test end-to-end
-  - Deploy backend to Railway/Heroku
-  - Deploy frontend to Vercel/Netlify
-  - Configure production database
-  - End-to-end testing
-  - Performance optimization
-
-## Detailed Sub-tasks
-
-### Technical Specifications
-- **Database Schema**: See `database-schema.sql`
-- **API Endpoints**: See `api-specification.md`
-
-### Component Props
-```javascript
-// TopicSelector.jsx
-const TopicSelector = ({ topics, selectedTopics, onTopicChange, loading }) => {}
-
-// PuzzleGrid.jsx  
-const PuzzleGrid = ({ grid, onCellChange, currentCell, answers }) => {}
-
-// ClueList.jsx
-const ClueList = ({ clues, direction, onClueClick, completedClues }) => {}
-```
-
-### Key Files to Create
-- `backend/src/services/crosswordGenerator.js` - Core algorithm
-- `backend/src/controllers/puzzleController.js` - API handlers
-- `frontend/src/hooks/useCrossword.js` - State management
-- `frontend/src/utils/gridHelpers.js` - Grid utilities
-- `frontend/src/styles/puzzle.css` - Crossword styling
-
-## Priority Order
-1. Setup project structure and basic backend
-2. Implement word placement algorithm
-3. Create basic frontend with grid display
-4. Add topic selection and API integration
-5. Implement interactive features
-6. Polish UI/UX and deploy
+## 🎯 Current Status: **Phases 1-5 Complete - Phase 6 (LLM Enhancement) In Progress**
+
+## ✅ COMPLETED PHASES (Phases 1-5)
+
+### ✅ Phase 1: Project Setup 
+- [x] ✅ Set up project structure and initialize repositories
+  - [x] Create frontend/ and backend/ directories
+  - [x] Initialize package.json files
+  - [x] Set up Git repository
+  - [x] Modern ES modules configuration
+
+### ✅ Phase 2: Data Management (JSON-based)
+- [x] ✅ Create data structure and seed data
+  - [x] JSON-based word lists by topic (animals.json, science.json, etc.)
+  - [x] 400+ words with quality clues
+  - [x] In-memory caching system
+  - [x] WordService for data management
+
+### ✅ Phase 3: Core Algorithm Development
+- [x] ✅ Implement advanced crossword generation algorithm
+  - [x] Smart word selection with crossword suitability scoring
+  - [x] Sophisticated grid placement with intersection optimization
+  - [x] Robust backtracking with timeout handling
+  - [x] Grid optimization with automatic trimming
+
+### ✅ Phase 4: Backend API
+- [x] ✅ Build comprehensive backend API endpoints
+  - [x] GET /api/topics - List available topics
+  - [x] POST /api/generate - Generate crossword puzzle
+  - [x] POST /api/validate - Validate user answers
+  - [x] GET /api/words/:topic - Get words for topic
+  - [x] GET /api/health - Health check
+  - [x] Error handling, rate limiting, CORS, security headers
+
+### ✅ Phase 5: Frontend Components & Features
+- [x] ✅ Create all frontend components
+  - [x] TopicSelector with multi-select buttons and visual feedback
+  - [x] PuzzleGrid with CSS Grid layout and interactive cells
+  - [x] ClueList component (Across/Down) with click navigation
+  - [x] LoadingSpinner with generation progress messages
+  - [x] PuzzleControls (Reset/Reveal/Generate buttons)
+
+### ✅ Phase 6: Interactive Features
+- [x] ✅ Implement full interactive crossword functionality
+  - [x] Click-to-focus input cells with keyboard navigation
+  - [x] Real-time input validation and auto-uppercase
+  - [x] Completion detection and success messages
+  - [x] Solution reveal functionality
+
+### ✅ Phase 7: User Experience & Styling
+- [x] ✅ Professional UI/UX with responsive design
+  - [x] Mobile-responsive design (tested on iPhone 14)
+  - [x] Professional color scheme and typography
+  - [x] Loading states and error messages
+  - [x] Smooth user interactions
+
+### ✅ Phase 8: Deployment
+- [x] ✅ Deploy to production
+  - [x] Docker containerization
+  - [x] HuggingFace Spaces deployment
+  - [x] Public access at https://vimalk78-abc123.hf.space/
+  - [x] Production environment configuration
+
+---
+
+## 🚀 CURRENT FOCUS: Phase 6 - LLM-Enhanced Dynamic Word Generation
+
+### 🔄 IN PROGRESS
+
+#### 6.1 Core LLM Infrastructure
+- [ ] Install and configure HuggingFace dependencies
+  - [ ] Add `@huggingface/inference` package to backend
+  - [ ] Set up environment variables for HF API keys
+  - [ ] Create HuggingFace account and configure access tokens
+
+- [ ] Implement EmbeddingWordService class
+  - [ ] Create `backend/src/services/embeddingWordService.js`
+  - [ ] Integrate `sentence-transformers/all-MiniLM-L6-v2` model
+  - [ ] Implement semantic similarity search for word generation
+  - [ ] Add error handling and fallback to static words
+
+#### 6.2 Dynamic Word Generation
+- [ ] Build topic-aware word generation system
+  - [ ] Implement semantic word discovery using embeddings
+  - [ ] Create word quality filtering for crossword suitability
+  - [ ] Add word difficulty scoring and classification
+  - [ ] Implement content validation (filter inappropriate words)
+
+- [ ] Enhance word selection algorithm
+  - [ ] Integrate AI-generated words with existing crossword algorithm
+  - [ ] Optimize word selection for better grid placement
+  - [ ] Add intersection-aware word generation
+
+#### 6.3 LLM-Powered Clue Generation
+- [ ] Implement intelligent clue generation
+  - [ ] Set up small language model for clue creation
+  - [ ] Create template-based clue generation with topic context
+  - [ ] Ensure crossword-appropriate clue formatting
+  - [ ] Add clue quality validation and scoring
+
+- [ ] Enhance clue system
+  - [ ] Context-aware clue generation based on topic
+  - [ ] Difficulty-matched clue complexity
+  - [ ] Multiple clue variations per word
+  - [ ] A/B testing for clue quality
+
+#### 6.4 Advanced Caching Implementation
+- [ ] Design multi-tier cache architecture
+  - [ ] L1: In-Memory (session cache) - existing ✅
+  - [ ] L2: Redis integration for cross-session caching
+  - [ ] L3: Enhanced fallback to JSON files
+
+- [ ] Implement smart cache policies
+  - [ ] Hybrid TTL + LRU eviction strategy
+  - [ ] Usage-based scoring: `(frequency × 0.4) + (recency × 0.3) + (cost × 0.3)`
+  - [ ] Adaptive TTL based on API response times and error rates
+  - [ ] Topic-aware cache eviction with different TTL for popular vs niche topics
+
+#### 6.5 Performance & Reliability
+- [ ] Build robust fallback systems
+  - [ ] Graceful degradation when LLM APIs fail
+  - [ ] Offline mode with cached content
+  - [ ] Error recovery and retry logic with exponential backoff
+  - [ ] Health monitoring for LLM services
+
+- [ ] Optimize for performance
+  - [ ] Batch word generation requests
+  - [ ] Precompute popular topic combinations
+  - [ ] Async generation with real-time progress indicators
+  - [ ] Request deduplication and coalescence
+
+#### 6.6 Quality Control & Monitoring
+- [ ] Implement content validation systems
+  - [ ] Word appropriateness filtering
+  - [ ] Crossword intersection analysis for AI-generated words
+  - [ ] Difficulty consistency checking
+  - [ ] User feedback collection system
+
+- [ ] Add continuous improvement features
+  - [ ] Analytics for AI-generated content quality metrics
+  - [ ] Model performance monitoring
+  - [ ] User rating system for generated puzzles
+  - [ ] A/B testing framework for different models
+
+### 🎯 FUTURE ENHANCEMENTS (Phase 7+)
+
+#### 7.1 Advanced Features
+- [ ] Custom topic support
+  - [ ] User-defined topic combinations
+  - [ ] Real-time topic similarity recommendations
+  - [ ] Trending topic suggestions
+  - [ ] Personal topic history
+
+- [ ] Enhanced difficulty system
+  - [ ] AI-driven difficulty assessment
+  - [ ] Personalized difficulty scaling
+  - [ ] Learning curve adaptation
+  - [ ] Challenge progression system
+
+#### 7.2 User Experience Improvements
+- [ ] Advanced UI features
+  - [ ] Puzzle saving and sharing
+  - [ ] User accounts and puzzle history
+  - [ ] Social features (puzzle sharing, challenges)
+  - [ ] Mobile app development
+
+#### 7.3 Analytics & Business Intelligence
+- [ ] User behavior analytics
+- [ ] Content performance metrics
+- [ ] API usage monitoring
+- [ ] Cost optimization analysis
+
+## 📋 CURRENT SPRINT TASKS
+
+**Week 1-2 (Current)**:
+1. Set up HuggingFace integration
+2. Create EmbeddingWordService class
+3. Implement basic dynamic word generation
+4. Add Redis caching layer
+
+**Week 3-4**:
+1. LLM clue generation system
+2. Quality control and validation
+3. Performance optimization
+4. Comprehensive testing
+
+**Week 5-6**:
+1. Advanced caching strategies
+2. Error handling and fallbacks
+3. User feedback collection
+4. Production deployment of Phase 6
+
+## 🔗 Key Files Created ✅
+- ✅ `backend/src/services/crosswordGenerator.js` - Advanced algorithm
+- ✅ `backend/src/controllers/puzzleController.js` - API handlers
+- ✅ `backend/src/services/wordService.js` - Data management
+- ✅ `frontend/src/hooks/useCrossword.js` - State management
+- ✅ `frontend/src/utils/gridHelpers.js` - Grid utilities
+- ✅ `frontend/src/styles/puzzle.css` - Professional styling
+- ✅ `backend/src/routes/api.js` - API routing
+- ✅ `Dockerfile` - Production deployment
+
+## 🎯 Next Priority Tasks
+1. **LLM Integration Setup** - HuggingFace API and embeddings
+2. **Dynamic Word Generation** - Semantic similarity-based word discovery
+3. **Advanced Caching** - Redis integration with smart eviction policies
+4. **Quality Control** - Validation and feedback systems