Interactive Chess

1. Project Overview

The goal of this project was to develop a fully functional, browser-based chess application suitable for both casual players and ambitious amateurs. The app was designed not only to offer a smooth gaming experience in Player-vs-Player (PvP) and Player-vs-Environment (PvE) modes but also to create genuine added value through the integration of advanced AI functions. The focus was on a clean, intuitive user interface, responsive design, and high performance.

2. The Challenge

Developing a chess application presents several complex challenges:

Implementing Game Rules: The exact implementation of all chess rules—including special moves like castling, en passant captures, and pawn promotion—is fundamental and prone to errors.

• Developing an AI Opponent: Creating a computer opponent whose difficulty is scalable to provide a challenge for various skill levels without freezing the browser due to excessive computational load.
• Responsive User Experience: The design had to adapt seamlessly to a variety of screen sizes, from large desktop monitors to small smartphone displays, without sacrificing functionality or aesthetics.
• Meaningful AI Integration: Beyond pure gameplay, external AI services (Google Gemini) were to be connected to provide the user with analysis, learning, and strategy tools.
• Performance Optimization: AI calculations, in particular, could not be allowed to impair the interactivity of the user interface (UI freeze).

3. The Solution

To meet these challenges, a well-thought-out technological approach was chosen, and a range of key features were implemented.

Technology Stack:
The application was deliberately developed with vanilla JavaScript, HTML5, and modern CSS3. This decision against a heavy front-end framework like React or Angular allowed for maximum control over the code, lean loading times, and optimized performance.

Core Features:

• Robust Chess Engine: An engine written in pure JavaScript forms the core of the application. It validates moves, detects check, checkmate, and stalemate situations, and manages the entire game state.
• Scalable AI Opponent:
  • The computer opponent is based on the minimax algorithm with alpha-beta pruning for increased efficiency.
  • Three difficulty levels (Easy, Medium, Hard) were implemented, differing in the search depth of the algorithm.
  • To ensure performance, the AI calculations are offloaded to a Web Worker. This runs in a separate background thread, preventing the user interface from blocking during the computer’s thinking time.
• Intelligent & Responsive UI/UX:
  • A dark/light mode adapts to user preferences and system settings.
  • A flexible layout using CSS Flexbox and Grid ensures optimal display on all devices.
  • Visual feedback, such as highlighting possible moves, marking the king when in check, and a clear display of captured pieces and move history, creates an intuitive user experience.
• Integration of the Gemini API: The application leverages the power of Google Gemini to provide the player with unique tools:
  • Hint: Suggests a good next move and briefly explains the reason.
  • Analysis: Evaluates the last move played.
  • Strategy: Provides general strategic recommendations for the current position.
  • Opening: Recognizes and names the chess opening being played.
  • Summary: Creates a narrative summary of the game after it ends.

4. The Result

The result is a sophisticated, high-performance, and visually appealing chess application that runs directly in the browser. It demonstrates that complex logic and advanced features can be realized without the use of large frameworks. The well-conceived architecture, with the Web Worker for the AI and seamless API integration, provides a fluid and educational experience that goes far beyond a simple chess simulation.

5. Outlook

The application’s modular codebase provides an excellent foundation for future expansions. Conceivable next steps include implementing an online multiplayer mode, connecting user accounts to save games and statistics, and expanding the analysis functions.