+import { ChessRules, PiPo, Move } from "@/base_rules";
+import { ArrayFun } from "@/utils/array";
+import { randInt } from "@/utils/alea";
+
+// TODO:
+
+export const VariantRules = class HiddenRules extends ChessRules {
+ static get HasFlags() {
+ return false;
+ }
+
+ static get HasEnpassant() {
+ return false;
+ }
+
+ // Analyse in Hidden mode makes no sense
+ static get CanAnalyze() {
+ return false;
+ }
+
+ // Moves are revealed only when game ends
+ static get ShowMoves() {
+ return "none";
+ }
+
+ static get HIDDEN_DECODE() {
+ return {
+ s: "p",
+ t: "q",
+ u: "r",
+ c: "b",
+ o: "n",
+ l: "k"
+ };
+ }
+ static get HIDDEN_CODE() {
+ return {
+ p: "s",
+ q: "t",
+ r: "u",
+ b: "c",
+ n: "o",
+ k: "l"
+ };
+ }
+
+ // Turn a hidden piece or revealed piece into revealed piece:
+ static Decode(p) {
+ if (Object.keys(V.HIDDEN_DECODE).includes(p))
+ return V.HIDDEN_DECODE[p];
+ return p;
+ }
+
+ static get PIECES() {
+ return ChessRules.PIECES.concat(Object.values(V.HIDDEN_CODE));
+ }
+
+ // Pieces can be hidden :)
+ getPiece(i, j) {
+ const piece = this.board[i][j].charAt(1);
+ if (Object.keys(V.HIDDEN_DECODE).includes(piece))
+ return V.HIDDEN_DECODE[piece];
+ return piece;
+ }
+
+ // Scan board for kings positions (no castling)
+ scanKingsRooks(fen) {
+ this.kingPos = { w: [-1, -1], b: [-1, -1] };
+ const fenRows = V.ParseFen(fen).position.split("/");
+ for (let i = 0; i < fenRows.length; i++) {
+ let k = 0; //column index on board
+ for (let j = 0; j < fenRows[i].length; j++) {
+ switch (fenRows[i].charAt(j)) {
+ case "k":
+ case "l":
+ this.kingPos["b"] = [i, k];
+ break;
+ case "K":
+ case "L":
+ this.kingPos["w"] = [i, k];
+ break;
+ default: {
+ const num = parseInt(fenRows[i].charAt(j));
+ if (!isNaN(num)) k += num - 1;
+ }
+ }
+ k++;
+ }
+ }
+ }
+
+ getPpath(b, color, score) {
+ if (Object.keys(V.HIDDEN_DECODE).includes(b[1])) {
+ // Supposed to be hidden.
+ if (score == "*" && (!color || color != b[0]))
+ return "Hidden/" + b[0] + "p";
+ // Else: condition OK to show the piece
+ return b[0] + V.HIDDEN_DECODE[b[1]];
+ }
+ // The piece is already not supposed to be hidden:
+ return b;
+ }
+
+ getBasicMove([sx, sy], [ex, ey], tr) {
+ if (
+ tr &&
+ Object.keys(V.HIDDEN_DECODE).includes(this.board[sx][sy].charAt(1))
+ ) {
+ // The transformed piece is a priori hidden
+ tr.p = V.HIDDEN_CODE[tr.p];
+ }
+ let mv = new Move({
+ appear: [
+ new PiPo({
+ x: ex,
+ y: ey,
+ c: tr ? tr.c : this.getColor(sx, sy),
+ p: tr ? tr.p : this.board[sx][sy].charAt(1)
+ })
+ ],
+ vanish: [
+ new PiPo({
+ x: sx,
+ y: sy,
+ c: this.getColor(sx, sy),
+ p: this.board[sx][sy].charAt(1)
+ })
+ ]
+ });
+
+ // The opponent piece disappears if we take it
+ if (this.board[ex][ey] != V.EMPTY) {
+ mv.vanish.push(
+ new PiPo({
+ x: ex,
+ y: ey,
+ c: this.getColor(ex, ey),
+ p: this.board[ex][ey].charAt(1)
+ })
+ );
+ // Pieces are revealed when they capture
+ mv.appear[0].p = V.Decode(mv.appear[0].p);
+ }
+
+ return mv;
+ }
+
+ // What are the king moves from square x,y ?
+ getPotentialKingMoves(sq) {
+ // No castling:
+ return this.getSlideNJumpMoves(
+ sq,
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
+ "oneStep"
+ );
+ }
+
+ filterValid(moves) {
+ return moves;
+ }
+
+ static GenRandInitFen() {
+ let pieces = { w: new Array(8), b: new Array(8) };
+ // Shuffle pieces + pawns on two first ranks
+ for (let c of ["w", "b"]) {
+ let positions = ArrayFun.range(16);
+
+ // Get random squares for bishops
+ let randIndex = 2 * randInt(8);
+ const bishop1Pos = positions[randIndex];
+ // The second bishop must be on a square of different color
+ let randIndex_tmp = 2 * randInt(8) + 1;
+ const bishop2Pos = positions[randIndex_tmp];
+ // Remove chosen squares
+ positions.splice(Math.max(randIndex, randIndex_tmp), 1);
+ positions.splice(Math.min(randIndex, randIndex_tmp), 1);
+
+ // Get random squares for knights
+ randIndex = randInt(14);
+ const knight1Pos = positions[randIndex];
+ positions.splice(randIndex, 1);
+ randIndex = randInt(13);
+ const knight2Pos = positions[randIndex];
+ positions.splice(randIndex, 1);
+
+ // Get random squares for rooks
+ randIndex = randInt(12);
+ const rook1Pos = positions[randIndex];
+ positions.splice(randIndex, 1);
+ randIndex = randInt(11);
+ const rook2Pos = positions[randIndex];
+ positions.splice(randIndex, 1);
+
+ // Get random square for queen
+ randIndex = randInt(10);
+ const queenPos = positions[randIndex];
+ positions.splice(randIndex, 1);
+
+ // Get random square for king
+ randIndex = randInt(9);
+ const kingPos = positions[randIndex];
+ positions.splice(randIndex, 1);
+
+ // Pawns position are all remaining slots:
+ for (let p of positions)
+ pieces[c][p] = "s";
+
+ // Finally put the shuffled pieces in the board array
+ pieces[c][rook1Pos] = "u";
+ pieces[c][knight1Pos] = "o";
+ pieces[c][bishop1Pos] = "c";
+ pieces[c][queenPos] = "t";
+ pieces[c][kingPos] = "l";
+ pieces[c][bishop2Pos] = "c";
+ pieces[c][knight2Pos] = "o";
+ pieces[c][rook2Pos] = "u";
+ }
+ let upFen = pieces["b"].join("");
+ upFen = upFen.substr(0,8) + "/" + upFen.substr(8).split("").reverse().join("");
+ let downFen = pieces["b"].join("").toUpperCase();
+ downFen = downFen.substr(0,8) + "/" + downFen.substr(8).split("").reverse().join("");
+ return upFen + "/8/8/8/8/" + downFen + " w 0";
+ }
+
+ getCheckSquares() {
+ return [];
+ }
+
+ updateVariables(move) {
+ super.updateVariables(move);
+ if (
+ move.vanish.length >= 2 &&
+ [V.KING,V.HIDDEN_CODE[V.KING]].includes(move.vanish[1].p)
+ ) {
+ // We took opponent king
+ this.kingPos[this.turn] = [-1, -1];
+ }
+ }
+
+ unupdateVariables(move) {
+ super.unupdateVariables(move);
+ const c = move.vanish[0].c;
+ const oppCol = V.GetOppCol(c);
+ if (this.kingPos[oppCol][0] < 0)
+ // Last move took opponent's king:
+ this.kingPos[oppCol] = [move.vanish[1].x, move.vanish[1].y];
+ }
+
+ getCurrentScore() {
+ const color = this.turn;
+ const kp = this.kingPos[color];
+ if (kp[0] < 0)
+ // King disappeared
+ return color == "w" ? "0-1" : "1-0";
+ // Assume that stalemate is impossible:
+ return "*";
+ }
+
+ getComputerMove() {
+ const color = this.turn;
+ let moves = this.getAllValidMoves();
+ for (let move of moves) {
+ move.eval = 0; //a priori...
+
+ // Can I take something ? If yes, do it with some probability
+ if (move.vanish.length == 2 && move.vanish[1].c != color) {
+ // OK this isn't a castling move
+ const myPieceVal = V.VALUES[move.appear[0].p];
+ const hisPieceVal = Object.keys(V.HIDDEN_DECODE).includes(move.vanish[1].p)
+ ? undefined
+ : V.VALUES[move.vanish[1].p];
+ if (!hisPieceVal) {
+ // Opponent's piece is unknown: do not take too much risk
+ move.eval = -myPieceVal + 1.5; //so that pawns always take
+ }
+ // Favor captures
+ else if (myPieceVal <= hisPieceVal)
+ move.eval = hisPieceVal - myPieceVal + 1;
+ else {
+ // Taking a pawn with minor piece,
+ // or minor piece or pawn with a rook,
+ // or anything but a queen with a queen,
+ // or anything with a king.
+ move.eval = hisPieceVal - myPieceVal;
+ }
+ } else {
+ // If no capture, favor small step moves,
+ // but sometimes move the knight anyway
+ const penalty = V.Decode(move.vanish[0].p) != V.KNIGHT
+ ? Math.abs(move.end.x - move.start.x) + Math.abs(move.end.y - move.start.y)
+ : (Math.random() < 0.5 ? 3 : 1);
+ move.eval -= penalty / (V.size.x + V.size.y - 1);
+ }
+
+ // TODO: also favor movements toward the center?
+ }
+
+ moves.sort((a, b) => b.eval - a.eval);
+ let candidates = [0];
+ for (let j = 1; j < moves.length && moves[j].eval == moves[0].eval; j++)
+ candidates.push(j);
+ return moves[candidates[randInt(candidates.length)]];
+ }
+
+ getNotation(move) {
+ // Translate final square
+ const finalSquare = V.CoordsToSquare(move.end);
+
+ const piece = this.getPiece(move.start.x, move.start.y);
+ if (piece == V.PAWN) {
+ // Pawn move
+ let notation = "";
+ if (move.vanish.length > move.appear.length) {
+ // Capture
+ const startColumn = V.CoordToColumn(move.start.y);
+ notation = startColumn + "x" + finalSquare;
+ }
+ else notation = finalSquare;
+ if (move.appear.length > 0 && !["p","s"].includes(move.appear[0].p)) {
+ // Promotion
+ const appearPiece = V.Decode(move.appear[0].p);
+ notation += "=" + appearPiece.toUpperCase();
+ }
+ return notation;
+ }
+ // Piece movement
+ return (
+ piece.toUpperCase() +
+ (move.vanish.length > move.appear.length ? "x" : "") +
+ finalSquare
+ );
+ }
+};