private static CheckStatus analyseCheckAfterEnpassent(
SimpleChessBoardInterface game, boolean whiteInCheck, Move lastMove) {
final Position kingPos = game.getKingPosition(whiteInCheck);
final List<Position> attackPositions = new ArrayList<Position>(2);
final Figure attackFigure = game.getFigure(lastMove.to);
Position passiveAttacker = getPassiveAttacker(game, kingPos, lastMove.from);
if (passiveAttacker == null) {
// an attackpath may have opend over the diagonal of the removed pawn
Position removedPawnPos = Position.get(lastMove.from.row, lastMove.to.column);
passiveAttacker = getPassiveAttacker(game, kingPos, removedPawnPos);
}
if (attackFigure.isReachable(kingPos, game)) {
attackPositions.add(attackFigure.getPosition());
}
if (passiveAttacker != null) {
attackPositions.add(passiveAttacker);
}
switch (attackPositions.size()) {
case 0:
return CheckStatus.NO_CHECK;
case 1:
return getPossiblePositions(kingPos, attackPositions.get(0));
case 2:
return CheckStatus.DOUBLE_CHECK;
default:
throw new IllegalStateException(
"more than 2 attackers are impossible " + attackPositions.size());
}
}
private static CheckStatus analyseCheckAfterPawnTransform(
SimpleChessBoardInterface game, boolean whiteInCheck, Move lastMove) {
final Position kingPos = game.getKingPosition(whiteInCheck);
final Figure transformedPawn = game.getFigure(lastMove.to);
final List<Position> attackPositions = new ArrayList<Position>(2);
final Position passiveAttacker = getPassiveAttacker(game, kingPos, lastMove.from);
if (transformedPawn.isReachable(kingPos, game)) {
attackPositions.add(lastMove.to);
}
if (passiveAttacker != null && !passiveAttacker.equalsPosition(lastMove.to)) {
attackPositions.add(passiveAttacker);
}
switch (attackPositions.size()) {
case 0:
return CheckStatus.NO_CHECK;
case 1:
return getPossiblePositions(kingPos, attackPositions.get(0));
case 2:
return CheckStatus.DOUBLE_CHECK;
default:
throw new IllegalStateException(
"more than 2 attackers are impossible " + attackPositions.size());
}
}
private static CheckStatus analyseCheckAfterRochade(
SimpleChessBoardInterface game, boolean whiteInCheck, Move lastMove) {
final Position kingPos = game.getKingPosition(whiteInCheck);
final int rock_row = lastMove.to.row;
final int rock_column = lastMove.to.column == 2 ? 3 : 5;
final Position rockPos = Position.get(rock_row, rock_column);
final Figure rock = game.getFigure(rockPos);
if (rock.isReachable(kingPos, game)) return getPossiblePositions(kingPos, rockPos);
return CheckStatus.NO_CHECK;
}
public static CheckStatus analyseCheck(SimpleChessBoardInterface game, boolean whiteInCheck) {
final Position kingPos = game.getKingPosition(whiteInCheck);
final boolean isWhite = game.getFigure(kingPos).isWhite();
final List<Position> attackPositions = new ArrayList<Position>(2);
isCheckByBishopOrQueen(game, kingPos, attackPositions, isWhite);
isCheckByKing(game, kingPos, attackPositions);
isCheckByKnight(game, kingPos, attackPositions, isWhite);
isCheckByPawn(game, kingPos, attackPositions, isWhite);
isCheckByRockOrQueen(game, kingPos, attackPositions, isWhite);
switch (attackPositions.size()) {
case 0:
return CheckStatus.NO_CHECK;
case 1:
return getPossiblePositions(kingPos, attackPositions.get(0));
case 2:
return CheckStatus.DOUBLE_CHECK;
default:
throw new IllegalStateException(
"more than 2 attackers are impossible " + attackPositions.size());
}
}
public static CheckStatus analyseCheck(
SimpleChessBoardInterface game, boolean whiteInCheck, ExtendedMove lastMove) {
if (lastMove == null) {
return analyseCheck(game, whiteInCheck);
}
if (lastMove.isEnpassent()) return analyseCheckAfterEnpassent(game, whiteInCheck, lastMove);
if (lastMove.isRochade()) return analyseCheckAfterRochade(game, whiteInCheck, lastMove);
if (lastMove.pawnTransformed())
return analyseCheckAfterPawnTransform(game, whiteInCheck, lastMove);
final Position kingPos = game.getKingPosition(whiteInCheck);
final Figure movedFigure = game.getFigure(lastMove.to);
final List<Position> attackPositions = new ArrayList<Position>(2);
if (movedFigure.isReachable(kingPos, game)) {
attackPositions.add(lastMove.to);
}
Position passiveAttacker = getPassiveAttacker(game, kingPos, lastMove.from);
if (passiveAttacker != null) {
attackPositions.add(passiveAttacker);
}
switch (attackPositions.size()) {
case 0:
return CheckStatus.NO_CHECK;
case 1:
return getPossiblePositions(kingPos, attackPositions.get(0));
case 2:
return CheckStatus.DOUBLE_CHECK;
default:
throw new IllegalStateException(
"more than 2 attackers are impossible " + attackPositions.size());
}
}
