chess_interface_dart

Complete chess functionalities including FEN initialization, en-passant, checkmate and draw rules. This is a pure dart package for backend and doesn't include flutter components for front-end. Visit chess_interface for complete front-end package

Features

✅ Built-in move validation for all standard piece types
🔄 Supports en passant, castling, and pawn promotion logic
📐 Interface-driven board interaction for flexible state management
⏱️ Countdown stream for both players.

Getting Started

Add the package to your pubspec.yaml:

dependencies:
  chess_interface_dart:
    git:
      url: https://github.com/mryadavdilip/chess_interface_dart.git

dependencies:
  chess_interface_dart: ^1.1.0

Then import the pure Dart API:

import 'package:chess_interface_dart/logical_interface/interface.dart';

Note: chess_interface_dart is backend/rules only and does not ship any Flutter widgets or assets.

Example

For a runnable example, see:

example/main.dart
example/README.md

import 'package:chess_interface_dart/arbiter/arbiter.dart';
import 'package:chess_interface_dart/logical_interface/interface.dart';
import 'package:chess_interface_dart/logical_interface/move_validator.dart';
import 'package:chess_interface_dart/logical_interface/position.dart';

void main() {
  final game = ChessBoardInterface(
    fen: 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1',
    timeLimit: const Duration(minutes: 10),
  );

  final arbiter = Arbiter(
    onGameOver: (gameOverBy) {
      print('Game ended: $gameOverBy');
    },
  );

  arbiter.countdownSpectator(game);
  arbiter.checkForGameEnd(game);

  // Example move validation + move.
  final from = Position(row: 6, col: 4); // e2
  final to = Position(row: 4, col: 4);   // e4

  if (MoveValidator.isValidMove(game, from, to)) {
    game.move(from, to);
  }
}

Move Validation

Use MoveValidator.isValidMove() to validate legal chess moves:

bool isValid = MoveValidator.isValidMove(ChessBoardInterface game, Position from, Position to);

It supports:

All standard chess moves
Pawn special rules
Castling logic (including history tracking)
En passant and double pawn pushes

Arbiter

Arbiter to handle events like game over, time out and pawn promotion:

And more..

File Structure

arbiter.dart – Game over, timeOut, and promotion handler
interface.dart – Board interaction interface
move_validator.dart – Move legality checker
piece.dart – Piece model and asset loader

Contributing

Contributions are welcome! Please open issues and pull requests to help improve this Package.

License

MIT License. See LICENSE for details.