+++ /dev/null
-import { ChessRules } from "@/base_rules";
-import { randInt } from "@/utils/alea";
-
-export class MarseilleRules extends ChessRules {
- static IsGoodEnpassant(enpassant) {
- const squares = enpassant.split(",");
- if (squares.length > 2) return false;
- for (let sq of squares) {
- if (sq != "-") {
- const ep = V.SquareToCoords(sq);
- if (isNaN(ep.x) || !V.OnBoard(ep)) return false;
- }
- }
- return true;
- }
-
- // There may be 2 enPassant squares (if 2 pawns jump 2 squares in same turn)
- getEnpassantFen() {
- return this.epSquares[this.epSquares.length - 1].map(
- epsq => epsq === undefined
- ? "-" //no en-passant
- : V.CoordsToSquare(epsq)
- ).join(",");
- }
-
- setOtherVariables(fen) {
- const parsedFen = V.ParseFen(fen);
- this.setFlags(parsedFen.flags);
- this.epSquares = [parsedFen.enpassant.split(",").map(sq => {
- if (sq != "-") return V.SquareToCoords(sq);
- return undefined;
- })];
- this.scanKings(fen);
- // Extract subTurn from turn indicator: "w" (first move), or
- // "w1" or "w2" white subturn 1 or 2, and same for black
- this.turn = parsedFen.turn;
- this.subTurn = 1;
- }
-
- getEnpassantCaptures([x, y], shiftX) {
- let moves = [];
- // En passant: always OK if subturn 1,
- // OK on subturn 2 only if enPassant was played at subturn 1
- // (and if there are two e.p. squares available).
- const Lep = this.epSquares.length;
- const epSquares = this.epSquares[Lep - 1]; //always at least one element
- let epSqs = [];
- epSquares.forEach(sq => {
- if (sq) epSqs.push(sq);
- });
- if (epSqs.length == 0) return moves;
- const oppCol = V.GetOppCol(this.getColor(x, y));
- for (let sq of epSqs) {
- if (
- this.subTurn == 1 ||
- (epSqs.length == 2 &&
- // Was this en-passant capture already played at subturn 1 ?
- // (Or maybe the opponent filled the en-passant square with a piece)
- this.board[epSqs[0].x][epSqs[0].y] != V.EMPTY)
- ) {
- if (
- sq.x == x + shiftX &&
- Math.abs(sq.y - y) == 1 &&
- // Add condition "enemy pawn must be present"
- this.getPiece(x, sq.y) == V.PAWN &&
- this.getColor(x, sq.y) == oppCol
- ) {
- let epMove = this.getBasicMove([x, y], [sq.x, sq.y]);
- epMove.vanish.push({
- x: x,
- y: sq.y,
- p: "p",
- c: oppCol
- });
- moves.push(epMove);
- }
- }
- }
- return moves;
- }
-
- play(move) {
- move.flags = JSON.stringify(this.aggregateFlags());
- move.turn = this.turn + this.subTurn;
- V.PlayOnBoard(this.board, move);
- const epSq = this.getEpSquare(move);
- if (this.movesCount == 0) {
- // First move in game
- this.turn = "b";
- this.epSquares.push([epSq]);
- this.movesCount = 1;
- }
- // Does this move give check on subturn 1? If yes, skip subturn 2
- else if (this.subTurn == 1 && this.underCheck(V.GetOppCol(this.turn))) {
- this.turn = V.GetOppCol(this.turn);
- this.epSquares.push([epSq]);
- move.checkOnSubturn1 = true;
- this.movesCount++;
- } else {
- if (this.subTurn == 2) {
- this.turn = V.GetOppCol(this.turn);
- let lastEpsq = this.epSquares[this.epSquares.length - 1];
- lastEpsq.push(epSq);
- } else {
- this.epSquares.push([epSq]);
- this.movesCount++;
- }
- this.subTurn = 3 - this.subTurn;
- }
- this.postPlay(move);
- }
-
- postPlay(move) {
- const c = move.turn.charAt(0);
- const piece = move.vanish[0].p;
- const firstRank = c == "w" ? V.size.x - 1 : 0;
-
- if (piece == V.KING && move.appear.length > 0) {
- this.kingPos[c][0] = move.appear[0].x;
- this.kingPos[c][1] = move.appear[0].y;
- this.castleFlags[c] = [V.size.y, V.size.y];
- return;
- }
- const oppCol = V.GetOppCol(c);
- const oppFirstRank = V.size.x - 1 - firstRank;
- if (
- move.start.x == firstRank && //our rook moves?
- this.castleFlags[c].includes(move.start.y)
- ) {
- const flagIdx = (move.start.y == this.castleFlags[c][0] ? 0 : 1);
- this.castleFlags[c][flagIdx] = V.size.y;
- } else if (
- move.end.x == oppFirstRank && //we took opponent rook?
- this.castleFlags[oppCol].includes(move.end.y)
- ) {
- const flagIdx = (move.end.y == this.castleFlags[oppCol][0] ? 0 : 1);
- this.castleFlags[oppCol][flagIdx] = V.size.y;
- }
- }
-
- undo(move) {
- this.disaggregateFlags(JSON.parse(move.flags));
- V.UndoOnBoard(this.board, move);
- if (this.movesCount == 1 || !!move.checkOnSubturn1 || this.subTurn == 2) {
- // The move may not be full, but is fully undone:
- this.epSquares.pop();
- // Moves counter was just incremented:
- this.movesCount--;
- } else {
- // Undo the second half of a move
- let lastEpsq = this.epSquares[this.epSquares.length - 1];
- lastEpsq.pop();
- }
- this.turn = move.turn[0];
- this.subTurn = parseInt(move.turn[1]);
- super.postUndo(move);
- }
-
- // NOTE: GenRandInitFen() is OK,
- // since at first move turn indicator is just "w"
-
- static get VALUES() {
- return {
- p: 1,
- r: 5,
- n: 3,
- b: 3,
- q: 7, //slightly less than in orthodox game
- k: 1000
- };
- }
-
- // No alpha-beta here, just adapted min-max at depth 2(+1)
- getComputerMove() {
- const maxeval = V.INFINITY;
- const color = this.turn;
- const oppCol = V.GetOppCol(this.turn);
-
- // Search best (half) move for opponent turn
- const getBestMoveEval = () => {
- let score = this.getCurrentScore();
- if (score != "*") {
- if (score == "1/2") return 0;
- return maxeval * (score == "1-0" ? 1 : -1);
- }
- let moves = this.getAllValidMoves();
- let res = oppCol == "w" ? -maxeval : maxeval;
- for (let m of moves) {
- this.play(m);
- score = this.getCurrentScore();
- // Now turn is oppCol,2 if m doesn't give check
- // Otherwise it's color,1. In both cases the next test makes sense
- if (score != "*") {
- if (score == "1/2")
- res = oppCol == "w" ? Math.max(res, 0) : Math.min(res, 0);
- else {
- // Found a mate
- this.undo(m);
- return maxeval * (score == "1-0" ? 1 : -1);
- }
- }
- const evalPos = this.evalPosition();
- res = oppCol == "w" ? Math.max(res, evalPos) : Math.min(res, evalPos);
- this.undo(m);
- }
- return res;
- };
-
- let moves11 = this.getAllValidMoves();
- let doubleMoves = [];
- // Rank moves using a min-max at depth 2
- for (let i = 0; i < moves11.length; i++) {
- this.play(moves11[i]);
- if (this.turn != color) {
- // We gave check with last move: search the best opponent move
- doubleMoves.push({ moves: [moves11[i]], eval: getBestMoveEval() });
- } else {
- let moves12 = this.getAllValidMoves();
- for (let j = 0; j < moves12.length; j++) {
- this.play(moves12[j]);
- doubleMoves.push({
- moves: [moves11[i], moves12[j]],
- eval: getBestMoveEval()
- });
- this.undo(moves12[j]);
- }
- }
- this.undo(moves11[i]);
- }
-
- doubleMoves.sort((a, b) => {
- return (color == "w" ? 1 : -1) * (b.eval - a.eval);
- });
- let candidates = [0]; //indices of candidates moves
- for (
- let i = 1;
- i < doubleMoves.length && doubleMoves[i].eval == doubleMoves[0].eval;
- i++
- ) {
- candidates.push(i);
- }
-
- const selected = doubleMoves[randInt(candidates.length)].moves;
- if (selected.length == 1) return selected[0];
- return selected;
- }
-};
projects / vchess.git / blobdiff