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checkmate complete

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This commit is contained in:
Lucas Morgan
2022-06-10 21:53:05 -05:00
parent dabdb6c6b0
commit 2dcc6ca417
7 changed files with 53 additions and 66 deletions
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89
Shogi.Domain/StandardRules.cs
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@@ -1,4 +1,5 @@
using Shogi.Domain.Pathing;
using Shogi.Domain.Pieces;
using BoardTile = System.Collections.Generic.KeyValuePair<System.Numerics.Vector2, Shogi.Domain.Pieces.Piece>;
namespace Shogi.Domain
@@ -9,7 +10,7 @@ namespace Shogi.Domain
internal StandardRules(ShogiBoardState board)
{
this.boardState = board;
boardState = board;
}
/// <summary>
@@ -179,19 +180,17 @@ namespace Shogi.Domain
return threatenedPiece.WhichPiece == WhichPiece.King;
}
internal bool IsPlayerInCheckMate(WhichPlayer whichPlayer)
internal bool IsOpponentInCheckMate()
{
// Assume checkmate, then try to disprove.
if (!boardState.InCheck.HasValue) return false;
// Get all pieces from "other player" who threaten the king in question.
var otherPlayer = whichPlayer == WhichPlayer.Player1 ? WhichPlayer.Player2 : WhichPlayer.Player1;
var tilesOccupiedByOtherPlayer = boardState.GetTilesOccupiedBy(otherPlayer);
var kingPosition = whichPlayer == WhichPlayer.Player1
// Get all pieces from opponent who threaten the king in question.
var opponent = boardState.WhoseTurn == WhichPlayer.Player1 ? WhichPlayer.Player2 : WhichPlayer.Player1;
var tilesOccupiedByOpponent = boardState.GetTilesOccupiedBy(opponent);
var kingPosition = boardState.WhoseTurn == WhichPlayer.Player1
? boardState.Player1KingPosition
: boardState.Player2KingPosition;
var threats = tilesOccupiedByOtherPlayer.Where(tile => PieceHasLineOfSight(tile, kingPosition)).ToList();
var threats = tilesOccupiedByOpponent.Where(tile => PieceHasLineOfSight(tile, kingPosition)).ToList();
if (threats.Count == 1)
{
/* If there is exactly one threat it is possible to block the check.
@@ -200,7 +199,7 @@ namespace Shogi.Domain
*/
var threat = threats.Single();
var pathFromThreatToKing = threat.Value.GetPathFromStartToEnd(threat.Key, kingPosition);
var tilesThatCouldBlockTheThreat = boardState.GetTilesOccupiedBy(whichPlayer);
var tilesThatCouldBlockTheThreat = boardState.GetTilesOccupiedBy(boardState.WhoseTurn);
foreach (var threatBlockingPosition in pathFromThreatToKing)
{
var tilesThatDoBlockThreat = tilesThatCouldBlockTheThreat
@@ -218,25 +217,35 @@ namespace Shogi.Domain
/*
* If no ability to block the check, maybe the king can evade check by moving.
*/
// TODO: Implement this in the Piece class instead.
var possibleSafePositions = new[]
foreach (var maybeSafePosition in GetPossiblePositionsForKing(this.boardState.WhoseTurn))
{
Direction.Up, Direction.Down, Direction.Left, Direction.Right, Direction.UpLeft, Direction.UpRight, Direction.DownLeft, Direction.DownRight
}
.Select(direction => kingPosition + direction);
foreach (var maybeSafePosition in possibleSafePositions)
{
threats = tilesOccupiedByOpponent
.Where(tile => PieceHasLineOfSight(tile, maybeSafePosition))
.ToList();
if (!threats.Any())
{
return false;
}
}
}
return true;
}
private IList<Vector2> GetPossiblePositionsForKing(WhichPlayer whichPlayer)
{
var kingPosition = whichPlayer == WhichPlayer.Player1
? boardState.Player1KingPosition
: boardState.Player2KingPosition;
return false;
return King.KingPaths
.Select(path => path.Direction + kingPosition)
.Where(newPosition => newPosition.IsInsideBoardBoundary())
// Where tile at position is empty, meaning the king could move there.
.Where(newPosition => boardState[newPosition] == null)
.ToList();
}
private bool PieceHasLineOfSight(BoardTile tile, Vector2 lineOfSightTarget)
@@ -244,41 +253,7 @@ namespace Shogi.Domain
var path = tile.Value.GetPathFromStartToEnd(tile.Key, lineOfSightTarget);
return path
.SkipLast(1)
.All(position => this.boardState[ShogiBoardState.ToBoardNotation(position)] == null);
}
public bool EvaluateCheckmate_Old()
{
if (!boardState.InCheck.HasValue) return false;
// Assume true and try to disprove.
var isCheckmate = true;
//boardState.ForEachNotNull((piece, from) => // For each piece...
//{
// Short circuit
//if (!isCheckmate) return;
//if (piece.Owner == boardState.InCheck) // ...owned by the player in check...
//{
// ...evaluate if any move gets the player out of check.
//PathEvery(from, (other, position) =>
//{
// var simulationBoard = new StandardRules(new ShogiBoardState(board));
// var fromNotation = ShogiBoardState.ToBoardNotation(from);
// var toNotation = ShogiBoardState.ToBoardNotation(position);
// var simulationResult = simulationBoard.Move(fromNotation, toNotation, false);
// if (simulationResult.Success)
// {
// //if (!IsPlayerInCheckAfterMove(from, position, board.InCheck.Value))
// //{
// // isCheckmate = false;
// //}
// }
//});
//}
// TODO: Assert that a player could not place a piece from their hand to avoid check.
//});
return isCheckmate;
.All(position => boardState[ShogiBoardState.ToBoardNotation(position)] == null);
}
}
}