<a href='https://play.google.com/store/apps/details?id=com.shenmareparas.chess'><img alt='Chess App Icon' src="https://github.com/shenmareparas/Chess/assets/112749923/54c38dbd-7a06-416e-8419-09f27654cbcd" width = 250/></a>

♟️ AI Chess - Flutter Chess Game

A feature-rich chess application built with Flutter and Flame engine, offering both single-player AI modes with varying difficulty levels and offline two-player gameplay. The app features beautiful customizable themes, multiple piece styles, and a powerful chess AI powered by the minimax algorithm with alpha-beta pruning.

<a href='https://play.google.com/store/apps/details?id=com.shenmareparas.chess'><img alt='Get it on Google Play' src='https://play.google.com/intl/en_us/badges/images/generic/en_badge_web_generic.png' width='300px'/></a>

✨ Features

🎮 Game Modes

• Single Player: Play against an intelligent AI opponent with 5 difficulty levels
• Two Player Mode: Offline multiplayer on the same device
• Side Selection: Choose to play as white, black, or random
• Timed Games: Optional time controls for competitive play

🎨 Customization

• 8 Beautiful Themes: Including Grey, Dark, Amoled, Lewis, Cherry Funk, Sage, Warm Tan, and Jargon Jade
• 7 Piece Themes: Classic, Angular, 8-Bit, Letters, Video Chess, Lewis Chessmen, and Mexico City
• Dark Mode Support: Multiple dark theme options including pure AMOLED black
• Custom Font: Jura font for elegant typography

🎯 Gameplay Features

• Move History: Track all moves throughout the game using Standard Algebraic Notation (SAN)
• Undo/Redo: Take back moves or replay them (configurable)
• Move Hints: Visual indicators for valid moves
• Board Notation: Algebraic notation (a-h, 1-8) coordinates on the board borders
• Sound Effects: Audio feedback for piece movements
• Board Rotation: Automatic board rotation based on turn
• Promotion Handling: Full support for pawn promotion
• Check Detection: Visual indicators for check and checkmate
• Stalemate Detection: Proper game-end condition handling

🤖 AI Features

• 5 Difficulty Levels: From beginner to expert (depth 1-5)
• Minimax Algorithm: With alpha-beta pruning optimization
• Iterative Deepening: Ensures best move ordering
• Quiescence Search: Avoids horizon effect for captures
• Null Move Pruning & LMR: Advanced search optimizations
• Opening Book: Pre-calculated moves for distinct openings

📸 Screenshots

Add your app screenshots here

🛠️ Technologies Used

• Flutter - UI framework
• Flame - 2D game engine for chess board rendering
• Provider - State management
• Shared Preferences - Local data persistence
• Flame Audio - Sound effects
• URL Launcher - External links

📦 Installation

Prerequisites

• Flutter SDK (3.0.0 or higher)
• Dart SDK (3.0.0 or higher)
• Android Studio / Xcode (for mobile development)
• A device or emulator

Steps

1. Clone the repository

   git clone https://github.com/shenmareparas/Chess.git
   cd Chess
   

2. Install dependencies

   flutter pub get
   

3. Run the app

   flutter run
   

4. Build for production (optional)

   # Android
   flutter build apk --release
   
   # iOS
   flutter build ios --release
   

📁 Project Structure

lib/
├── main.dart                 # App entry point
├── model/
│   ├── app_model.dart       # Main app state management
│   ├── app_themes.dart      # Theme definitions
│   ├── user_preferences.dart # SharedPreferences wrapper
│   └── player.dart          # Player enumerations
├── logic/
│   ├── chess_board.dart     # Board logic
│   ├── chess_game.dart      # Game controller
│   ├── chess_piece.dart     # Piece models
│   ├── chess_piece_sprite.dart  # Piece rendering
│   ├── shared_functions.dart    # Utility functions
│   ├── game_state_storage.dart  # History & undo/redo
│   ├── timer_service.dart   # Game clocks
│   ├── audio_service.dart   # Sound manager
│   └── move_calculation/    # Move validation and AI logic
└── views/
    ├── main_menu_view.dart  # Main menu screen
    ├── chess_view.dart      # Game screen
    ├── settings_view.dart   # Settings screen
    └── components/          # Reusable UI components

🧠 AI Algorithm

The chess AI uses the Minimax algorithm with alpha-beta pruning to determine optimal moves:

How It Works

1. Minimax Algorithm: Evaluates the game tree by simulating moves and counter-moves
2. Alpha-Beta Pruning: Optimizes search by eliminating branches that won't affect the final decision
3. Advanced Optimizations: Utilizes Quiescence Search, Null Move Pruning, and Late Move Reductions (LMR)
4. Depth-Based Difficulty:
   • Level 1: Depth 1 (1 half-move lookahead)
   • Level 2: Depth 2 (1 full move)
   • Level 3: Depth 3 (1.5 full moves)
   • Level 4: Depth 4 (2 full moves)
   • Level 5: Depth 5 (2.5 full moves)

Position Evaluation

The AI evaluates positions based on:

• Material advantage (piece values)
• Piece positioning and mobility
• King safety
• Pawn structure
• Control of center squares

Learn more: Alpha-Beta Pruning on Wikipedia

⚙️ Configuration

The app stores user preferences locally using SharedPreferences:

• Selected theme
• Piece theme preference
• Move history visibility
• Sound settings
• Hint display settings
• Board Rotation preference
• Board Notation visibility
• Undo/Redo availability

🎯 Usage

1. Start a New Game: From the main menu, configure your game settings
2. Select Mode: Choose between 1-player (vs AI) or 2-player mode
3. Choose Difficulty: For AI games, select from 5 difficulty levels
4. Customize: Pick your preferred theme and piece style
5. Play: Tap pieces to select them, then tap valid squares to move

🤝 Contributing

Contributions are welcome! Here's how you can help:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

📝 License

This project is licensed under the MIT License.

👨‍💻 Author

Paras Shenmare

• GitHub: @shenmareparas
• Google Play: Download Chess

🙏 Acknowledgments

• Chess piece graphics from various open-source sets
• Jura font by Daniel Johnson
• Flutter and Flame communities

📞 Support

If you encounter any issues or have suggestions, please open an issue.

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⭐ If you like this project, please give it a star on GitHub!