530 lines
18 KiB
Java
530 lines
18 KiB
Java
package dev.kske.chess.board;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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import java.util.Objects;
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import java.util.regex.Matcher;
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import java.util.regex.Pattern;
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import dev.kske.chess.board.Piece.Color;
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import dev.kske.chess.board.Piece.Type;
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/**
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* Project: <strong>Chess</strong><br>
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* File: <strong>Board.java</strong><br>
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* Created: <strong>01.07.2019</strong><br>
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* Author: <strong>Kai S. K. Engelbart</strong>
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*/
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public class Board {
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private Piece[][] boardArr = new Piece[8][8];
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private Map<Color, Position> kingPos = new HashMap<>();
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private Log log = new Log();
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private static final Map<Type, int[][]> positionScores;
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static {
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positionScores = new HashMap<>();
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positionScores.put(Type.KING,
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new int[][] { new int[] { -3, -4, -4, -5, -5, -4, -4, -3 }, new int[] { -3, -4, -4, -5, -4, -4, -4, -3 },
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new int[] { -3, -4, -4, -5, -4, -4, -4, -3 }, new int[] { -3, -4, -4, -5, -4, -4, -4, -3 },
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new int[] { -2, -3, -3, -2, -2, -2, -2, -1 }, new int[] { -1, -2, -2, -2, -2, -2, -2, -1 },
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new int[] { 2, 2, 0, 0, 0, 0, 2, 2 }, new int[] { 2, 3, 1, 0, 0, 1, 3, 2 } });
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positionScores.put(Type.QUEEN,
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new int[][] { new int[] { -2, -1, -1, -1, -1, -1, -1, -2 }, new int[] { -1, 0, 0, 0, 0, 0, 0, -1 },
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new int[] { -1, 0, 1, 1, 1, 1, 0, -1 }, new int[] { -1, 0, 1, 1, 1, 1, 0, -1 }, new int[] { 0, 0, 1, 1, 1, 1, 0, -1 },
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new int[] { -1, 1, 1, 1, 1, 1, 0, -1 }, new int[] { -1, 0, 1, 0, 0, 0, 0, -1 },
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new int[] { -2, -1, -1, -1, -1, -1, -1, -2 } });
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positionScores.put(Type.ROOK,
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new int[][] { new int[] { 0, 0, 0, 0, 0, 0, 0, 0 }, new int[] { 1, 1, 1, 1, 1, 1, 1, 1 }, new int[] { -1, 0, 0, 0, 0, 0, 0, -1 },
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new int[] { -1, 0, 0, 0, 0, 0, 0, -1 }, new int[] { -1, 0, 0, 0, 0, 0, 0, -1 }, new int[] { -1, 0, 0, 0, 0, 0, 0, -1 },
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new int[] { -1, 0, 0, 0, 0, 0, 0, -1 }, new int[] { 0, 0, 0, 1, 1, 0, 0, 0 } });
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positionScores.put(Type.KNIGHT,
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new int[][] { new int[] { -5, -4, -3, -3, -3, -3, -4, -5 }, new int[] { -4, -2, 0, 0, 0, 0, -2, -4 },
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new int[] { -3, 0, 1, 2, 2, 1, 0, -3 }, new int[] { -3, 1, 2, 2, 2, 2, 1, -3 }, new int[] { -3, 0, 2, 2, 2, 2, 0, -1 },
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new int[] { -3, 1, 1, 2, 2, 1, 1, -3 }, new int[] { -4, -2, 0, 1, 1, 0, -2, -4 },
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new int[] { -5, -4, -3, -3, -3, -3, -4, -5 } });
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positionScores.put(Type.BISHOP,
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new int[][] { new int[] { -2, -1, -1, -1, -1, -1, -1, 2 }, new int[] { -1, 0, 0, 0, 0, 0, 0, -1 },
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new int[] { -1, 0, 1, 1, 1, 1, 0, -1 }, new int[] { -1, 1, 1, 1, 1, 1, 1, -1 }, new int[] { -1, 0, 1, 1, 1, 1, 0, -1 },
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new int[] { -1, 1, 1, 1, 1, 1, 1, -1 }, new int[] { -1, 1, 0, 0, 0, 0, 1, -1 },
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new int[] { -2, -1, -1, -1, -1, -1, -1, -2 } });
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positionScores.put(Type.PAWN,
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new int[][] { new int[] { 0, 0, 0, 0, 0, 0, 0, 0 }, new int[] { 5, 5, 5, 5, 5, 5, 5, 5 }, new int[] { 1, 1, 2, 3, 3, 2, 1, 1 },
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new int[] { 0, 0, 1, 3, 3, 1, 0, 0 }, new int[] { 0, 0, 0, 2, 2, 0, 0, 0 }, new int[] { 0, 0, -1, 0, 0, -1, 0, 0 },
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new int[] { 0, 1, 1, -2, -2, 1, 1, 0 }, new int[] { 0, 0, 0, 0, 0, 0, 0, 0 } });
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}
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/**
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* Initializes the board with the default chess starting position.
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*/
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public Board() { initDefaultPositions(); }
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/**
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* Creates a copy of another {@link Board} instance.<br>
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* The created object is a deep copy, but does not contain any move history
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* apart from the current {@link MoveNode}.
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*
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* @param other The {@link Board} instance to copy
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*/
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public Board(Board other) {
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boardArr = new Piece[8][8];
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for (int i = 0; i < 8; i++)
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for (int j = 0; j < 8; j++) {
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if (other.boardArr[i][j] == null) continue;
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boardArr[i][j] = (Piece) other.boardArr[i][j].clone();
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boardArr[i][j].board = this;
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}
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kingPos.putAll(other.kingPos);
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log = new Log(other.log, false);
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}
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/**
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* Moves a piece across the board if the move is legal.
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*
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* @param move The move to execute
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* @return {@code true}, if the attempted move was legal and thus executed
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*/
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public boolean attemptMove(Move move) {
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Piece piece = getPos(move);
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if (piece == null || !piece.isValidMove(move)) return false;
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else {
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// Set type after validation
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if (move.type == Move.Type.UNKNOWN) move.type = Move.Type.NORMAL;
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// Move piece
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move(move);
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// Revert move if it caused a check for its team
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if (checkCheck(piece.getColor())) {
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revert();
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return false;
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}
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return true;
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}
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}
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/**
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* Moves a piece across the board without checking if the move is legal.
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*
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* @param move The move to execute
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*/
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public void move(Move move) {
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Piece piece = getPos(move);
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Piece capturePiece = getDest(move);
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switch (move.type) {
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case PAWN_PROMOTION:
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setPos(move, null);
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// TODO: Select promotion
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setDest(move, new Queen(piece.getColor(), this));
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break;
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case EN_PASSANT:
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setDest(move, piece);
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setPos(move, null);
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boardArr[move.dest.x][move.dest.y - move.ySign] = null;
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break;
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case CASTLING:
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// Move the king
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setDest(move, piece);
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setPos(move, null);
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// Move the rook
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Move rookMove = move.dest.x == 6 ? new Move(7, move.pos.y, 5, move.pos.y) // Kingside
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: new Move(0, move.pos.y, 3, move.pos.y); // Queenside
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setDest(rookMove, getPos(rookMove));
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setPos(rookMove, null);
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break;
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case UNKNOWN:
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System.err.printf("Move of unknown type %s found!%n", move);
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case NORMAL:
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setDest(move, piece);
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setPos(move, null);
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break;
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default:
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System.err.printf("Move %s of unimplemented type found!%n", move);
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}
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// Update the king's position if the moved piece is the king
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if (piece.getType() == Type.KING) kingPos.put(piece.getColor(), move.dest);
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// Update log
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log.add(move, piece, capturePiece);
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}
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/**
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* Moves a piece across the board without checking if the move is legal.
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*
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* @param sanMove The move to execute in SAN (Standard Algebraic Notation)
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*/
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public void move(String sanMove) {
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Map<String, Pattern> patterns = new HashMap<>();
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patterns.put("pieceMove",
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Pattern.compile(
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"^(?<pieceType>[NBRQK])(?:(?<fromFile>[a-h])|(?<fromRank>[1-8])|(?<fromSquare>[a-h][1-8]))?x?(?<toSquare>[a-h][1-8])(?:\\+{0,2}|\\#)$"));
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patterns.put("pawnCapture",
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Pattern.compile("^(?<fromFile>[a-h])(?<fromRank>[1-8])?x(?<toSquare>[a-h][1-8])(?<promotedTo>[NBRQK])?(?:\\+{0,2}|\\#)?$"));
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patterns.put("pawnPush", Pattern.compile("^(?<toSquare>[a-h][1-8])(?<promotedTo>[NBRQK])?(?:\\+{0,2}|\\#)$"));
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patterns.put("castling", Pattern.compile("^(?<queenside>O-O-O)|(?<kingside>O-O)(?:\\+{0,2}|\\#)?$"));
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patterns.forEach((patternName, pattern) -> {
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Matcher m = pattern.matcher(sanMove);
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if (m.find()) {
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Position pos = null, dest = null;
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Move.Type moveType = Move.Type.NORMAL;
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switch (patternName) {
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case "pieceMove":
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dest = Position.fromLAN(m.group("toSquare"));
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if (m.group("fromSquare") != null) pos = Position.fromLAN(m.group("fromSquare"));
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else {
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Type type = Type.fromFirstChar(m.group("pieceType").charAt(0));
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char file;
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int rank;
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if (m.group("fromFile") != null) {
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file = m.group("fromFile").charAt(0);
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rank = get(type, file);
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pos = Position.fromLAN(String.format("%c%d", file, rank));
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} else if (m.group("fromRank") != null) {
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rank = Integer.parseInt(m.group("fromRank").substring(0, 1));
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file = get(type, rank);
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pos = Position.fromLAN(String.format("%c%d", file, rank));
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} else pos = get(type, dest);
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}
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break;
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case "pawnCapture":
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dest = Position.fromLAN(m.group("toSquare"));
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char file = m.group("fromFile").charAt(0);
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int rank = m.group("fromRank") == null ? get(Type.PAWN, file) : Integer.parseInt(m.group("fromRank"));
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pos = Position.fromLAN(String.format("%c%d", file, rank));
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break;
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case "pawnPush":
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dest = Position.fromLAN(m.group("toSquare"));
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// TODO: Pawn promotion
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int step = log.getActiveColor() == Color.WHITE ? 1 : -1;
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// One step forward
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if (boardArr[dest.x][dest.y + step] != null) pos = new Position(dest.x, dest.y + step);
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// Double step forward
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else pos = new Position(dest.x, dest.y + 2 * step);
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break;
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case "castling":
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pos = new Position(4, log.getActiveColor() == Color.WHITE ? 7 : 0);
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dest = new Position(m.group("kingside") != null ? 6 : 2, pos.y);
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moveType = Move.Type.CASTLING;
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break;
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}
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move(new Move(pos, dest, moveType));
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return;
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}
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});
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}
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/**
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* Reverts the last move.
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*/
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public void revert() {
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MoveNode moveNode = log.getLast();
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Move move = moveNode.move;
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Piece capturedPiece = moveNode.capturedPiece;
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switch (move.type) {
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case PAWN_PROMOTION:
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setPos(move, new Pawn(getDest(move).getColor(), this));
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setDest(move, capturedPiece);
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break;
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case EN_PASSANT:
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setPos(move, getDest(move));
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setDest(move, null);
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boardArr[move.dest.x][move.dest.y - move.ySign] = new Pawn(getPos(move).getColor().opposite(), this);
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break;
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case CASTLING:
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// Move the king
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setPos(move, getDest(move));
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setDest(move, null);
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// Move the rook
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Move rookMove = move.dest.x == 6 ? new Move(5, move.pos.y, 7, move.pos.y) // Kingside
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: new Move(3, move.pos.y, 0, move.pos.y); // Queenside
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setDest(rookMove, getPos(rookMove));
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setPos(rookMove, null);
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break;
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case UNKNOWN:
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System.err.printf("Move of unknown type %s found!%n", move);
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case NORMAL:
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setPos(move, getDest(move));
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setDest(move, capturedPiece);
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break;
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default:
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System.err.printf("Move %s of unimplemented type found!%n", move);
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}
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// Update the king's position if the moved piece is the king
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if (getPos(move).getType() == Type.KING) kingPos.put(getPos(move).getColor(), move.pos);
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// Update log
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log.removeLast();
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}
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/**
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* Generated every legal move for one color
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*
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* @param color The color to generate the moves for
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* @return A list of all legal moves
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*/
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public List<Move> getMoves(Color color) {
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List<Move> moves = new ArrayList<>();
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for (int i = 0; i < 8; i++)
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for (int j = 0; j < 8; j++)
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if (boardArr[i][j] != null && boardArr[i][j].getColor() == color) moves.addAll(boardArr[i][j].getMoves(new Position(i, j)));
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return moves;
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}
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public List<Move> getMoves(Position pos) { return get(pos).getMoves(pos); }
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/**
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* Checks, if the king is in check.
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*
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* @param color The color of the king to check
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* @return {@code true}, if the king is in check
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*/
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public boolean checkCheck(Color color) {
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for (int i = 0; i < 8; i++)
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for (int j = 0; j < 8; j++) {
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Position pos = new Position(i, j);
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if (get(pos) != null && get(pos).getColor() != color && get(pos).isValidMove(new Move(pos, kingPos.get(color)))) return true;
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}
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return false;
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}
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/**
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* Checks, if the king is in checkmate.
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* This requires the king to already be in check!
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*
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* @param color The color of the king to check
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* @return {@code true}, if the king is in checkmate
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*/
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public boolean checkCheckmate(Color color) {
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// Return false immediately if the king can move
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if (!getMoves(kingPos.get(color)).isEmpty()) return false;
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else {
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for (Move move : getMoves(color)) {
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move(move);
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boolean check = checkCheck(color);
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revert();
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if (!check) return false;
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}
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return true;
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}
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}
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public GameState getGameEventType(Color color) {
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return checkCheck(color) ? checkCheckmate(color) ? GameState.CHECKMATE : GameState.CHECK
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: getMoves(color).isEmpty() || log.getLast().halfmoveClock >= 50 ? GameState.STALEMATE : GameState.NORMAL;
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}
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/**
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* Evaluated the board.
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*
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* @param color The color to evaluate for
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* @return An positive number representing how good the position is
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*/
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public int evaluate(Color color) {
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int score = 0;
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for (int i = 0; i < 8; i++)
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for (int j = 0; j < 8; j++)
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if (boardArr[i][j] != null && boardArr[i][j].getColor() == color) {
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switch (boardArr[i][j].getType()) {
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case QUEEN:
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score += 90;
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break;
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case ROOK:
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score += 50;
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break;
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case KNIGHT:
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score += 30;
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break;
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case BISHOP:
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score += 30;
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break;
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case PAWN:
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score += 10;
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break;
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}
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if (positionScores.containsKey(boardArr[i][j].getType()))
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score += positionScores.get(boardArr[i][j].getType())[i][color == Color.WHITE ? j : 7 - j];
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}
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return score;
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}
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/**
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* Initialized the board array with the default chess pieces and positions.
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*/
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public void initDefaultPositions() {
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// Initialize pawns
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for (int i = 0; i < 8; i++) {
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boardArr[i][1] = new Pawn(Color.BLACK, this);
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boardArr[i][6] = new Pawn(Color.WHITE, this);
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}
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// Initialize kings
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boardArr[4][0] = new King(Color.BLACK, this);
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boardArr[4][7] = new King(Color.WHITE, this);
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// Initialize king position objects
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kingPos.put(Color.BLACK, new Position(4, 0));
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kingPos.put(Color.WHITE, new Position(4, 7));
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// Initialize queens
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boardArr[3][0] = new Queen(Color.BLACK, this);
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boardArr[3][7] = new Queen(Color.WHITE, this);
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// Initialize rooks
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boardArr[0][0] = new Rook(Color.BLACK, this);
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boardArr[0][7] = new Rook(Color.WHITE, this);
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boardArr[7][0] = new Rook(Color.BLACK, this);
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boardArr[7][7] = new Rook(Color.WHITE, this);
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// Initialize knights
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boardArr[1][0] = new Knight(Color.BLACK, this);
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boardArr[1][7] = new Knight(Color.WHITE, this);
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boardArr[6][0] = new Knight(Color.BLACK, this);
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boardArr[6][7] = new Knight(Color.WHITE, this);
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// Initialize bishops
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boardArr[2][0] = new Bishop(Color.BLACK, this);
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boardArr[2][7] = new Bishop(Color.WHITE, this);
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boardArr[5][0] = new Bishop(Color.BLACK, this);
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boardArr[5][7] = new Bishop(Color.WHITE, this);
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// Clear all other tiles
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for (int i = 0; i < 8; i++)
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for (int j = 2; j < 6; j++)
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boardArr[i][j] = null;
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log.reset();
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}
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@Override
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public int hashCode() {
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final int prime = 31;
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int result = 1;
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result = prime * result + Arrays.deepHashCode(boardArr);
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result = prime * result + Objects.hash(kingPos, log);
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return result;
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}
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@Override
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public boolean equals(Object obj) {
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if (this == obj) return true;
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if (obj == null) return false;
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if (getClass() != obj.getClass()) return false;
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Board other = (Board) obj;
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return Arrays.deepEquals(boardArr, other.boardArr) && Objects.equals(kingPos, other.kingPos) && Objects.equals(log, other.log);
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}
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/**
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* @param pos The position from which to return a piece
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* @return The piece at the position
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*/
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public Piece get(Position pos) { return boardArr[pos.x][pos.y]; }
|
|
|
|
/**
|
|
* Searches for a {@link Piece} inside a file (A - H).
|
|
*
|
|
* @param type The {@link Type} of the piece to search for
|
|
* @param file The file in which to search for the piece
|
|
* @return The rank (1 - 8) of the first piece with the specified type and
|
|
* current color in the file, or {@code -1} if there isn't any
|
|
*/
|
|
public int get(Type type, char file) {
|
|
int x = file - 97;
|
|
for (int i = 0; i < 8; i++)
|
|
if (boardArr[x][i] != null && boardArr[x][i].getType() == type && boardArr[x][i].getColor() == log.getActiveColor()) return 8 - i;
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* Searches for a {@link Piece} inside a rank (1 - 8).
|
|
*
|
|
* @param type The {@link Type} of the piece to search for
|
|
* @param rank The rank in which to search for the piece
|
|
* @return The file (A - H) of the first piece with the specified type and
|
|
* current color in the file, or {@code -} if there isn't any
|
|
*/
|
|
public char get(Type type, int rank) {
|
|
int y = rank - 1;
|
|
for (int i = 0; i < 8; i++)
|
|
if (boardArr[i][y] != null && boardArr[i][y].getType() == type && boardArr[i][y].getColor() == log.getActiveColor())
|
|
return (char) (i + 97);
|
|
return '-';
|
|
}
|
|
|
|
/**
|
|
* Searches for a {@link Piece} that can move to a {@link Position}.
|
|
*
|
|
* @param type The {@link Type} of the piece to search for
|
|
* @param dest The destination that the piece is required to reach
|
|
* @return The position of a piece that can move to the specified destination
|
|
*/
|
|
public Position get(Type type, Position dest) {
|
|
for (int i = 0; i < 8; i++)
|
|
for (int j = 0; j < 8; j++)
|
|
if (boardArr[i][j] != null && boardArr[i][j].getType() == type && boardArr[i][j].getColor() == log.getActiveColor()) {
|
|
Position pos = new Position(i, j);
|
|
if (boardArr[i][j].isValidMove(new Move(pos, dest))) return pos;
|
|
}
|
|
return null;
|
|
}
|
|
|
|
/**
|
|
* Places a piece at a position.
|
|
*
|
|
* @param pos The position to place the piece at
|
|
* @param piece The piece to place
|
|
*/
|
|
public void set(Position pos, Piece piece) { boardArr[pos.x][pos.y] = piece; }
|
|
|
|
/**
|
|
* @param move The move from which position to return a piece
|
|
* @return The piece at the position of the move
|
|
*/
|
|
public Piece getPos(Move move) { return get(move.pos); }
|
|
|
|
/**
|
|
* @param move The move from which destination to return a piece
|
|
* @return The piece at the destination of the move
|
|
*/
|
|
public Piece getDest(Move move) { return get(move.dest); }
|
|
|
|
/**
|
|
* Places a piece at the position of a move.
|
|
*
|
|
* @param move The move at which position to place the piece
|
|
* @param piece The piece to place
|
|
*/
|
|
public void setPos(Move move, Piece piece) { set(move.pos, piece); }
|
|
|
|
/**
|
|
* Places a piece at the destination of a move.
|
|
*
|
|
* @param move The move at which destination to place the piece
|
|
* @param piece The piece to place
|
|
*/
|
|
public void setDest(Move move, Piece piece) { set(move.dest, piece); }
|
|
|
|
/**
|
|
* @return The board array
|
|
*/
|
|
public Piece[][] getBoardArr() { return boardArr; }
|
|
|
|
/**
|
|
* @return The move log
|
|
*/
|
|
public Log getLog() { return log; }
|
|
}
|