Chess Engine

A comprehensive chess implementation in C# featuring a complete chess board representation, move validation, special moves, game state management, modern GUI interface, and AI opponent using Minimax algorithm. Thoroughly tested with 300+ automated test cases using GitHub Actions CI/CD pipeline.

Features

Core Chess Functionality

• Complete Chess Rules Implementation: Full support all standard chess rules and piece movements
• Special Moves Support:
  • Castling
  • En Passant captures
  • Pawn promotion
• Game State Detection
  • Check detection
  • Checkmate detection
  • Stalement detection
  • Draw conditions (50-move rule)

User Interface & Experience

• Cross-platform GUI: Built using Avalonia UI framework for Windows, macOS, and Linux
• Interactive Chess Board: click to move interface with visual feedback
• Real-Time Game State visualization:
  • Square highlighting for possible moves
  • Selected piece indication
  • King in check visual warning
  • Point advantage display
• AI button: Able to use AI to help determine next move
• Undo: full undo functionality with visual state updates

Artificial Intelligence

• Minimax Algorithm Implementation: Strategic AI opponent that evaluates positions
• Asynchronous AI Processing: makes sure the application does not crash

Technical Architecture

MVVM Pattern Implementation

The GUI follows the Model-View-ViewModel pattern:

• Model: ChessBoard - Pure game logic and state
• View: Avalonia UI components - Visual representation
• ViewModel: ChessViewModel - UI binding and interaction logic

Strategy Pattern

Each piece type implements its own movement strategy:

• PawnStrategy
• RookStrategy
• KnightStrategy
• BishopStrategy
• QueenStrategy
• KingStrategy

Move Types

• Normal: Standard piece movements
• CastleKingSide/CastleQueenSide: Castling moves
• PawnPromote: Pawn promotion with piece selection
• EnPassant: En passant captures

Quality Assurance

Comprehensive Testing Suite

• 300+ Automated Test Cases: Extensive test coverage ensuring reliability and correctness
• GitHub Actions CI/CD: Continuous integration pipeline running all tests on every commit
• Test Categories:
  • Unit tests for individual piece movements
  • Integration tests for complex game scenarios
  • Edge case validation (castling conditions, en passant timing, etc.)
  • Game state detection accuracy (checkmate, stalemate, draw conditions)
  • Move validation and legal move generation
  • Board state integrity after move application/undo

Technical Highlights

Efficient Board Representation

private byte[,] board = new byte[BoardSize, 4];

The board uses a compact 4-bit representation per square, storing both piece type and player information efficiently.

Contributing

This chess engine demonstrates advanced C# programming concepts including:

• Strategy design pattern for piece movements
• MVVM architectural pattern for GUI applications
• Efficient data structures and memory optimization
• Complex game logic implementation with comprehensive testing
• Asynchronous programming for responsive UI
• Cross-platform application development with Avalonia
• AI algorithm implementation (Minimax)
• Observable pattern for real-time UI updates