--- /dev/null
+import { ChessRules, Move, PiPo } from "@/base_rules";
+import { randInt } from "@/utils/alea";
+
+export class PocketknightRules extends ChessRules {
+ hoverHighlight(x, y) {
+ // Testing move validity results in an infinite update loop.
+ // TODO: find a way to test validity anyway.
+ return (this.subTurn == 2 && this.board[x][y] == V.EMPTY);
+ }
+
+ static IsGoodFlags(flags) {
+ // 4 for castle + 2 for knights
+ return !!flags.match(/^[a-z]{4,4}[01]{2,2}$/);
+ }
+
+ setFlags(fenflags) {
+ super.setFlags(fenflags); //castleFlags
+ this.knightFlags = fenflags.substr(4).split("").map(e => e == "1");
+ }
+
+ aggregateFlags() {
+ return [this.castleFlags, this.knightFlags];
+ }
+
+ disaggregateFlags(flags) {
+ this.castleFlags = flags[0];
+ this.knightFlags = flags[1];
+ }
+
+ setOtherVariables(fen) {
+ super.setOtherVariables(fen);
+ this.subTurn = 1;
+ }
+
+ static GenRandInitFen(randomness) {
+ // Add 2 knight flags
+ return ChessRules.GenRandInitFen(randomness)
+ .slice(0, -2) + "11 -";
+ }
+
+ getFlagsFen() {
+ return (
+ super.getFlagsFen() + this.knightFlags.map(e => e ? "1" : "0").join("")
+ );
+ }
+
+ getPotentialMovesFrom([x, y]) {
+ if (this.subTurn == 1) {
+ let moves = super.getPotentialMovesFrom([x, y]);
+ // If flag allow it, add "king capture"
+ if (
+ this.knightFlags[this.turn == 'w' ? 0 : 1] &&
+ this.getPiece(x, y) == V.KING
+ ) {
+ const kp = this.kingPos[V.GetOppCol(this.turn)];
+ moves.push(
+ new Move({
+ appear: [],
+ vanish: [],
+ start: { x: x, y: y },
+ end: { x: kp[0], y: kp[1] }
+ })
+ );
+ }
+ return moves;
+ }
+ // subTurn == 2: a move is a click, not handled here
+ return [];
+ }
+
+ filterValid(moves) {
+ if (this.subTurn == 2) return super.filterValid(moves);
+ const color = this.turn;
+ return moves.filter(m => {
+ this.play(m);
+ let res = false;
+ if (m.appear.length > 0)
+ // Standard check:
+ res = !this.underCheck(color);
+ else {
+ // "Capture king": find landing square not resulting in check
+ outerLoop: for (let i=0; i<8; i++) {
+ for (let j=0; j<8; j++) {
+ if (this.board[i][j] == V.EMPTY) {
+ const tMove = new Move({
+ appear: [
+ new PiPo({
+ x: i,
+ y: j,
+ c: color,
+ p: V.KNIGHT
+ })
+ ],
+ vanish: [],
+ start: { x: -1, y: -1 }
+ });
+ this.play(tMove);
+ const moveOk = !this.underCheck(color);
+ this.undo(tMove);
+ if (moveOk) {
+ res = true;
+ break outerLoop;
+ }
+ }
+ }
+ }
+ }
+ this.undo(m);
+ return res;
+ });
+ }
+
+ getAllValidMoves() {
+ if (this.subTurn == 1) return super.getAllValidMoves();
+ // Subturn == 2: only knight landings
+ let moves = [];
+ const color = this.turn;
+ for (let i=0; i<8; i++) {
+ for (let j=0; j<8; j++) {
+ if (this.board[i][j] == V.EMPTY) {
+ const tMove = new Move({
+ appear: [
+ new PiPo({
+ x: i,
+ y: j,
+ c: color,
+ p: V.KNIGHT
+ })
+ ],
+ vanish: [],
+ start: { x: -1, y: -1 }
+ });
+ this.play(tMove);
+ const moveOk = !this.underCheck(color);
+ this.undo(tMove);
+ if (moveOk) moves.push(tMove);
+ }
+ }
+ }
+ return moves;
+ }
+
+ doClick(square) {
+ if (isNaN(square[0])) return null;
+ // If subTurn == 2 && square is empty && !underCheck, then drop
+ if (this.subTurn == 2 && this.board[square[0]][square[1]] == V.EMPTY) {
+ const color = this.turn;
+ const tMove = new Move({
+ appear: [
+ new PiPo({
+ x: square[0],
+ y: square[1],
+ c: color,
+ p: V.KNIGHT
+ })
+ ],
+ vanish: [],
+ start: { x: -1, y: -1 }
+ });
+ this.play(tMove);
+ const moveOk = !this.underCheck(color);
+ this.undo(tMove);
+ if (moveOk) return tMove;
+ }
+ return null;
+ }
+
+ play(move) {
+ move.flags = JSON.stringify(this.aggregateFlags());
+ if (move.appear.length > 0) {
+ // Usual case or knight landing
+ if (move.vanish.length > 0) this.epSquares.push(this.getEpSquare(move));
+ else this.subTurn = 1;
+ this.turn = V.GetOppCol(this.turn);
+ this.movesCount++;
+ V.PlayOnBoard(this.board, move);
+ if (move.vanish.length > 0) this.postPlay(move);
+ }
+ else {
+ // "king capture"
+ this.subTurn = 2;
+ this.knightFlags[this.turn == 'w' ? 0 : 1] = false;
+ }
+ }
+
+ undo(move) {
+ this.disaggregateFlags(JSON.parse(move.flags));
+ if (move.appear.length > 0) {
+ if (move.vanish.length > 0) this.epSquares.pop();
+ else this.subTurn = 2;
+ this.turn = V.GetOppCol(this.turn);
+ this.movesCount--;
+ V.UndoOnBoard(this.board, move);
+ if (move.vanish.length > 0) this.postUndo(move);
+ }
+ else this.subTurn = 1;
+ }
+
+ getComputerMove() {
+ let moves = this.getAllValidMoves();
+ if (moves.length == 0) return null;
+ // Custom "search" at depth 1 (for now. TODO?)
+ const maxeval = V.INFINITY;
+ const color = this.turn;
+ const initEval = this.evalPosition();
+ moves.forEach(m => {
+ this.play(m);
+ m.eval = (color == "w" ? -1 : 1) * maxeval;
+ if (m.appear.length == 0) {
+ const moves2 = this.getAllValidMoves();
+ m.next = moves2[0];
+ moves2.forEach(m2 => {
+ this.play(m2);
+ const score = this.getCurrentScore();
+ let mvEval = 0;
+ if (["1-0", "0-1"].includes(score))
+ mvEval = (score == "1-0" ? 1 : -1) * maxeval;
+ else if (score == "*")
+ // Add small fluctuations to avoid dropping pieces always on the
+ // first square available.
+ mvEval = initEval + 0.05 - Math.random() / 10;
+ if (
+ (color == 'w' && mvEval > m.eval) ||
+ (color == 'b' && mvEval < m.eval)
+ ) {
+ m.eval = mvEval;
+ m.next = m2;
+ }
+ this.undo(m2);
+ });
+ }
+ else {
+ const score = this.getCurrentScore();
+ if (score != "1/2") {
+ if (score != "*") m.eval = (score == "1-0" ? 1 : -1) * maxeval;
+ else m.eval = this.evalPosition();
+ }
+ }
+ this.undo(m);
+ });
+ moves.sort((a, b) => {
+ return (color == "w" ? 1 : -1) * (b.eval - a.eval);
+ });
+ let candidates = [0];
+ for (let i = 1; i < moves.length && moves[i].eval == moves[0].eval; i++)
+ candidates.push(i);
+ const mIdx = candidates[randInt(candidates.length)];
+ if (!moves[mIdx].next) return moves[mIdx];
+ const move2 = moves[mIdx].next;
+ delete moves[mIdx]["next"];
+ return [moves[mIdx], move2];
+ }
+
+ getNotation(move) {
+ if (move.vanish.length > 0)
+ return super.getNotation(move);
+ if (move.appear.length == 0)
+ // "king capture"
+ return "-";
+ // Knight landing:
+ return "N@" + V.CoordsToSquare(move.end);
+ }
+};
projects / vchess.git / blobdiff