Build a chess game

• A Board of 8x8 squares and Piece classes (pawn, knight, bishop, rook, queen, king), each defining its own movement rules; pieces are blocked by others and may capture opponents only
• Game.move(from, to) validates the move (correct turn, piece movement, no self-check), updates the board, switches turns and appends to the move history in algebraic coordinates
• Check detection after every move: a move that leaves one's own king attacked is rejected, and the game status reports check
• Checkmate and stalemate are detected from the absence of legal moves for the player to move (with and without check)
• Special moves: castling (king and rook unmoved, empty squares between, king not passing through check), en passant, and pawn promotion (default queen)
• legalMoves(square) returns destinations for a piece, history() lists moves, and status() returns active, check, checkmate, stalemate or draw

Only after every requirement works.

• Draw rules: threefold repetition, fifty-move rule and insufficient material
• Undo and replay of moves, and loading a position from FEN
• A simple computer opponent using minimax with a small depth