104 lines
3.1 KiB
C#
104 lines
3.1 KiB
C#
namespace Shogi.Domain
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{
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/// <summary>
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/// Facilitates Shogi board state transitions, cognisant of Shogi rules.
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/// The board is always from Player1's perspective.
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/// [0,0] is the lower-left position, [8,8] is the higher-right position
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/// </summary>
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public sealed class Shogi
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{
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private readonly ShogiBoardState board;
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private readonly StandardRules rules;
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public string Error { get; private set; }
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public Shogi(ShogiBoardState board)
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{
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this.board = board;
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rules = new StandardRules(this.board);
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}
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//public Shogi(IList<Move> moves) : this(new ShogiBoardState())
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//{
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// for (var i = 0; i < moves.Count; i++)
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// {
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// if (!Move(moves[i]))
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// {
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// throw new InvalidOperationException($"Unable to construct ShogiBoard with the given move at index {i}.");
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// }
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// }
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//}
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public MoveResult CanMove(string from, string to, bool isPromotion)
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{
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// TODO: ShogiBoardState.FromBoardNotation should not throw an execption in this query method.
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var fromVector = ShogiBoardState.FromBoardNotation(from);
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var toVector = ShogiBoardState.FromBoardNotation(to);
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var simulator = new StandardRules(new ShogiBoardState(board));
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return simulator.Move(fromVector, toVector, isPromotion);
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}
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public MoveResult CanMove(WhichPiece pieceInHand, string to)
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{
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var toVector = ShogiBoardState.FromBoardNotation(to);
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var simulator = new StandardRules(new ShogiBoardState(board));
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return simulator.Move(pieceInHand, toVector);
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}
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public void Move(string from, string to, bool isPromotion)
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{
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var fromVector = ShogiBoardState.FromBoardNotation(from);
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var toVector = ShogiBoardState.FromBoardNotation(to);
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var moveResult = rules.Move(fromVector, toVector, isPromotion);
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if (!moveResult.Success)
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{
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throw new InvalidOperationException(moveResult.Reason);
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}
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var otherPlayer = board.WhoseTurn == WhichPlayer.Player1 ? WhichPlayer.Player2 : WhichPlayer.Player1;
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if (rules.EvaluateCheckAfterMove(fromVector, toVector, otherPlayer))
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{
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board.InCheck = otherPlayer;
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board.IsCheckmate = rules.EvaluateCheckmate();
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}
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else
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{
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board.InCheck = null;
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}
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}
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///// <summary>
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///// Attempts a given move. Returns false if the move is illegal.
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///// </summary>
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//private bool TryMove(Move move)
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//{
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// // Try making the move in a "throw away" board.
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// var simulator = new StandardRules(new ShogiBoardState(this.board));
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// var simulatedMoveResults = move.PieceFromHand.HasValue
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// ? simulator.PlaceFromHand(move)
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// : simulator.PlaceFromBoard(move);
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// if (!simulatedMoveResults)
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// {
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// // Surface the error description.
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// Error = simulationBoard.Error;
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// return false;
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// }
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// // If already in check, assert the move that resulted in check no longer results in check.
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// if (InCheck == WhoseTurn)
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// {
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// // Sneakily using this.WhoseTurn instead of validationBoard.WhoseTurn;
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// if (simulationBoard.EvaluateCheckAfterMove(MoveHistory[^1], WhoseTurn))
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// {
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// return false;
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// }
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// }
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// // The move is valid and legal; update board state.
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// if (move.PieceFromHand.HasValue) PlaceFromHand(move);
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// else PlaceFromBoard(move);
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// return true;
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//}
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}
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}
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