# HTML Chess Game - Complete Planning Documentation

## 📋 Project Overview

A browser-based chess game built with vanilla HTML, CSS, and JavaScript. This project demonstrates clean architecture, modular design, and comprehensive chess rule implementation without any external dependencies.

### 🎯 Objectives

- **Zero Dependencies**: Pure HTML/CSS/JavaScript implementation
- **Complete Chess Rules**: All standard chess rules including special moves
- **Clean Architecture**: Modular, maintainable, testable code
- **Professional Quality**: Production-ready code with comprehensive testing
- **Educational Value**: Well-documented code suitable for learning

## ✨ Features

### Core Gameplay
- ♟️ Full chess rule implementation (pawns, knights, bishops, rooks, queens, kings)
- 🎮 Interactive drag-and-drop piece movement
- 👁️ Move validation and legal move highlighting
- ✅ Check, checkmate, and stalemate detection
- 🔄 Turn-based gameplay with move history

### Special Moves
- 🏰 Castling (kingside and queenside)
- 🎯 En passant capture
- 👑 Pawn promotion with piece selection

### Game Management
- 📝 Move history with algebraic notation
- ⏮️ Undo/redo functionality
- 💾 Game state persistence (localStorage)
- 🔄 New game and reset options
- 🏆 Win/draw/resign conditions

### User Interface
- 🎨 Beautiful, responsive chess board
- 🖱️ Intuitive drag-and-drop interaction
- 💡 Visual feedback for legal moves
- 📊 Game status display
- 🎯 Captured pieces display
- ⏱️ Optional timer support

## 🏗️ Technology Stack

- **HTML5**: Semantic markup, drag-and-drop API
- **CSS3**: Grid layout, animations, responsive design
- **JavaScript (ES6+)**: Modules, classes, async/await
- **No frameworks or libraries**: Pure vanilla implementation

## 📚 Documentation Structure

This documentation package includes:

1. **[README.md](README.md)** (this file) - Project overview and quick start
2. **[IMPLEMENTATION_GUIDE.md](IMPLEMENTATION_GUIDE.md)** - Step-by-step implementation handbook
3. **[API_REFERENCE.md](API_REFERENCE.md)** - Complete API documentation
4. **[CHESS_RULES.md](CHESS_RULES.md)** - Chess rules and logic reference
5. **[DEVELOPER_GUIDE.md](DEVELOPER_GUIDE.md)** - Development workflow and best practices
6. **[HANDOFF_CHECKLIST.md](HANDOFF_CHECKLIST.md)** - Implementation checklist and timeline
7. **[diagrams/](diagrams/)** - Architecture and flow diagrams

## 🚀 Quick Start

### For Implementation Team

1. **Read the handoff checklist** → [HANDOFF_CHECKLIST.md](HANDOFF_CHECKLIST.md)
2. **Follow the implementation guide** → [IMPLEMENTATION_GUIDE.md](IMPLEMENTATION_GUIDE.md)
3. **Reference API docs as needed** → [API_REFERENCE.md](API_REFERENCE.md)
4. **Consult chess rules** → [CHESS_RULES.md](CHESS_RULES.md)

### For Reviewers

1. Review architecture diagrams in [diagrams/](diagrams/)
2. Check API specifications in [API_REFERENCE.md](API_REFERENCE.md)
3. Validate against requirements in [HANDOFF_CHECKLIST.md](HANDOFF_CHECKLIST.md)

### For End Users (After Implementation)

1. Open `index.html` in a modern browser
2. Start playing chess immediately
3. Use drag-and-drop to move pieces
4. Click pieces to see legal moves

## 📁 Project Structure

```
chess-game/
├── index.html              # Main HTML file
├── css/
│   ├── board.css          # Chess board styling
│   ├── pieces.css         # Piece styling
│   └── ui.css             # UI components
├── js/
│   ├── main.js            # Application entry point
│   ├── game/
│   │   ├── ChessGame.js   # Game controller
│   │   ├── Board.js       # Board state management
│   │   └── GameState.js   # Game state and history
│   ├── pieces/
│   │   ├── Piece.js       # Base piece class
│   │   ├── Pawn.js        # Pawn logic
│   │   ├── Knight.js      # Knight logic
│   │   ├── Bishop.js      # Bishop logic
│   │   ├── Rook.js        # Rook logic
│   │   ├── Queen.js       # Queen logic
│   │   └── King.js        # King logic
│   ├── moves/
│   │   ├── MoveValidator.js    # Move validation
│   │   ├── MoveGenerator.js    # Legal move generation
│   │   └── SpecialMoves.js     # Castling, en passant, promotion
│   ├── ui/
│   │   ├── BoardRenderer.js    # Board rendering
│   │   ├── DragDropHandler.js  # Drag-and-drop
│   │   └── UIController.js     # UI state management
│   └── utils/
│       ├── notation.js         # Chess notation (PGN, FEN)
│       ├── storage.js          # localStorage wrapper
│       └── helpers.js          # Utility functions
├── assets/
│   └── pieces/            # Piece images (SVG)
├── tests/
│   ├── unit/              # Unit tests
│   └── integration/       # Integration tests
└── docs/                  # This documentation
```

## 🎯 Success Criteria

### Functional Requirements
- ✅ All chess pieces move according to official rules
- ✅ All special moves work correctly (castling, en passant, promotion)
- ✅ Check and checkmate detection is accurate
- ✅ Game can be saved and restored
- ✅ Move history is properly tracked

### Non-Functional Requirements
- ✅ Code is modular and maintainable
- ✅ No external dependencies
- ✅ Works in all modern browsers
- ✅ Responsive design for different screen sizes
- ✅ 80%+ test coverage

### User Experience
- ✅ Intuitive drag-and-drop interface
- ✅ Clear visual feedback for legal moves
- ✅ Responsive and smooth animations
- ✅ Accessible keyboard navigation
- ✅ Clear game state indicators

## 🔧 Development Setup

### Prerequisites
- Modern web browser (Chrome, Firefox, Safari, Edge)
- Text editor or IDE
- Optional: Local web server for testing

### Running Locally
```bash
# Option 1: Simple file-based access
# Just open index.html in your browser

# Option 2: Using Python's built-in server
python -m http.server 8000

# Option 3: Using Node.js http-server
npx http-server -p 8000

# Then open http://localhost:8000 in your browser
```

## 🧪 Testing

### Manual Testing
1. Test each piece type individually
2. Verify special moves (castling, en passant, promotion)
3. Test check and checkmate scenarios
4. Verify UI interactions (drag-drop, click)
5. Test game save/load functionality

### Automated Testing
```bash
# Run all tests
npm test

# Run specific test suites
npm test -- --grep "MoveValidator"
npm test -- --grep "Piece"

# Generate coverage report
npm run test:coverage
```

## 📈 Project Timeline

- **Phase 1**: Core architecture and board (Week 1)
- **Phase 2**: Piece movement and validation (Week 2)
- **Phase 3**: Special moves and game logic (Week 3)
- **Phase 4**: UI polish and testing (Week 4)
- **Phase 5**: Documentation and deployment (Week 5)

See [HANDOFF_CHECKLIST.md](HANDOFF_CHECKLIST.md) for detailed timeline.

## 🤝 Contributing

### Code Style
- Use ES6+ features (classes, modules, arrow functions)
- Follow consistent naming conventions
- Add JSDoc comments for all public methods
- Keep functions small and focused
- Write tests for new features

### Commit Guidelines
- Use descriptive commit messages
- Reference issue numbers
- Keep commits atomic
- Run tests before committing

## 📞 Support

### Questions?
- Check the [IMPLEMENTATION_GUIDE.md](IMPLEMENTATION_GUIDE.md)
- Review [API_REFERENCE.md](API_REFERENCE.md)
- Consult [DEVELOPER_GUIDE.md](DEVELOPER_GUIDE.md)

### Issues?
- Check common pitfalls in implementation guide
- Review test cases for examples
- Consult chess rules reference

## 📄 License

This is a planning document for an educational chess game implementation.

## 🙏 Acknowledgments

This comprehensive planning documentation was created to ensure a smooth handoff to the implementation team. Every detail has been thought through to minimize ambiguity and maximize success.

---

**Ready to implement?** Start with [HANDOFF_CHECKLIST.md](HANDOFF_CHECKLIST.md) → [IMPLEMENTATION_GUIDE.md](IMPLEMENTATION_GUIDE.md)
