client/src/variants/Madhouse.js

   1 import { ChessRules, Move, PiPo } from "@/base_rules";
   2 import { randInt } from "@/utils/alea";
   3
   4 export class MadhouseRules extends ChessRules {
   5
   6   hoverHighlight(x, y) {
   7     // Testing move validity results in an infinite update loop.
   8     // TODO: find a way to test validity anyway.
   9     return (this.subTurn == 2 && this.board[x][y] == V.EMPTY);
  10   }
  11
  12   setOtherVariables(fen) {
  13     super.setOtherVariables(fen);
  14     this.subTurn = 1;
  15     this.firstMove = [];
  16   }
  17
  18   getPotentialMovesFrom([x, y]) {
  19     if (this.subTurn == 1) return super.getPotentialMovesFrom([x, y]);
  20     // subTurn == 2: a move is a click, not handled here
  21     return [];
  22   }
  23
  24   filterValid(moves) {
  25     if (this.subTurn == 2) return super.filterValid(moves);
  26     const color = this.turn;
  27     return moves.filter(m => {
  28       this.play(m);
  29       let res = false;
  30       if (m.vanish.length == 1 || m.appear.length == 2)
  31         // Standard check:
  32         res = !this.underCheck(color);
  33       else {
  34         // Capture: find landing square not resulting in check
  35         const boundary = (m.vanish[1].p != V.PAWN ? [0, 7] : [1, 6]);
  36         const sqColor =
  37           m.vanish[1].p == V.BISHOP
  38             ? (m.vanish[1].x + m.vanish[1].y) % 2
  39             : null;
  40         outerLoop: for (let i = boundary[0]; i <= boundary[1]; i++) {
  41           for (let j=0; j<8; j++) {
  42             if (
  43               this.board[i][j] == V.EMPTY &&
  44               (!sqColor || (i + j) % 2 == sqColor)
  45             ) {
  46               const tMove = new Move({
  47                 appear: [
  48                   new PiPo({
  49                     x: i,
  50                     y: j,
  51                     c: m.vanish[1].c,
  52                     p: m.vanish[1].p
  53                   })
  54                 ],
  55                 vanish: [],
  56                 start: { x: -1, y: -1 }
  57               });
  58               this.play(tMove);
  59               const moveOk = !this.underCheck(color);
  60               this.undo(tMove);
  61               if (moveOk) {
  62                 res = true;
  63                 break outerLoop;
  64               }
  65             }
  66           }
  67         }
  68       }
  69       this.undo(m);
  70       return res;
  71     });
  72   }
  73
  74   getAllValidMoves() {
  75     if (this.subTurn == 1) return super.getAllValidMoves();
  76     // Subturn == 2: only replacements
  77     let moves = [];
  78     const L = this.firstMove.length;
  79     const fm = this.firstMove[L - 1];
  80     const color = this.turn;
  81     const oppCol = V.GetOppCol(color);
  82     const boundary = (fm.vanish[1].p != V.PAWN ? [0, 7] : [1, 6]);
  83     const sqColor =
  84       fm.vanish[1].p == V.BISHOP
  85         ? (fm.vanish[1].x + fm.vanish[1].y) % 2
  86         : null;
  87     for (let i = boundary[0]; i < boundary[1]; i++) {
  88       for (let j=0; j<8; j++) {
  89         if (
  90           this.board[i][j] == V.EMPTY &&
  91           (!sqColor || (i + j) % 2 == sqColor)
  92         ) {
  93           const tMove = new Move({
  94             appear: [
  95               new PiPo({
  96                 x: i,
  97                 y: j,
  98                 c: oppCol,
  99                 p: fm.vanish[1].p
 100               })
 101             ],
 102             vanish: [],
 103             start: { x: -1, y: -1 }
 104           });
 105           this.play(tMove);
 106           const moveOk = !this.underCheck(color);
 107           this.undo(tMove);
 108           if (moveOk) moves.push(tMove);
 109         }
 110       }
 111     }
 112     return moves;
 113   }
 114
 115   doClick(square) {
 116     if (isNaN(square[0])) return null;
 117     // If subTurn == 2 && square is empty && !underCheck, then replacement
 118     if (this.subTurn == 2 && this.board[square[0]][square[1]] == V.EMPTY) {
 119       const L = this.firstMove.length;
 120       const fm = this.firstMove[L - 1];
 121       const color = this.turn;
 122       const oppCol = V.GetOppCol(color);
 123       if (
 124         (fm.vanish[1].p == V.PAWN && [0, 7].includes(square[0])) ||
 125         (
 126           fm.vanish[1].p == V.BISHOP &&
 127           (square[0] + square[1] + fm.vanish[1].x + fm.vanish[1].y) % 2 != 0
 128         )
 129       ) {
 130         // Pawns cannot be replaced on first or last rank,
 131         // bishops must be replaced on same square color.
 132         return null;
 133       }
 134       const tMove = new Move({
 135         appear: [
 136           new PiPo({
 137             x: square[0],
 138             y: square[1],
 139             c: oppCol,
 140             p: fm.vanish[1].p
 141           })
 142         ],
 143         vanish: [],
 144         start: { x: -1, y: -1 }
 145       });
 146       this.play(tMove);
 147       const moveOk = !this.underCheck(color);
 148       this.undo(tMove);
 149       if (moveOk) return tMove;
 150     }
 151     return null;
 152   }
 153
 154   play(move) {
 155     move.flags = JSON.stringify(this.aggregateFlags());
 156     if (move.vanish.length > 0) {
 157       this.epSquares.push(this.getEpSquare(move));
 158       this.firstMove.push(move);
 159     }
 160     V.PlayOnBoard(this.board, move);
 161     if (
 162       this.subTurn == 2 ||
 163       move.vanish.length == 1 ||
 164       move.appear.length == 2
 165     ) {
 166       this.turn = V.GetOppCol(this.turn);
 167       this.subTurn = 1;
 168       this.movesCount++;
 169     }
 170     else this.subTurn = 2;
 171     if (move.vanish.length > 0) this.postPlay(move);
 172   }
 173
 174   postPlay(move) {
 175     if (move.appear[0].p == V.KING)
 176       this.kingPos[move.appear[0].c] = [move.appear[0].x, move.appear[0].y];
 177     this.updateCastleFlags(move, move.appear[0].p, move.appear[0].c);
 178   }
 179
 180   undo(move) {
 181     this.disaggregateFlags(JSON.parse(move.flags));
 182     if (move.vanish.length > 0) {
 183       this.epSquares.pop();
 184       this.firstMove.pop();
 185     }
 186     V.UndoOnBoard(this.board, move);
 187     if (this.subTurn == 2) this.subTurn = 1;
 188     else {
 189       this.turn = V.GetOppCol(this.turn);
 190       this.movesCount--;
 191       this.subTurn = (move.vanish.length > 0 ? 1 : 2);
 192     }
 193     if (move.vanish.length > 0) super.postUndo(move);
 194   }
 195
 196   getComputerMove() {
 197     let moves = this.getAllValidMoves();
 198     if (moves.length == 0) return null;
 199     // Custom "search" at depth 1 (for now. TODO?)
 200     const maxeval = V.INFINITY;
 201     const color = this.turn;
 202     const initEval = this.evalPosition();
 203     moves.forEach(m => {
 204       this.play(m);
 205       m.eval = (color == "w" ? -1 : 1) * maxeval;
 206       if (m.vanish.length == 2 && m.appear.length == 1) {
 207         const moves2 = this.getAllValidMoves();
 208         m.next = moves2[0];
 209         moves2.forEach(m2 => {
 210           this.play(m2);
 211           const score = this.getCurrentScore();
 212           let mvEval = 0;
 213           if (["1-0", "0-1"].includes(score))
 214             mvEval = (score == "1-0" ? 1 : -1) * maxeval;
 215           else if (score == "*")
 216             // Add small fluctuations to avoid dropping pieces always on the
 217             // first square available.
 218             mvEval = initEval + 0.05 - Math.random() / 10;
 219           if (
 220             (color == 'w' && mvEval > m.eval) ||
 221             (color == 'b' && mvEval < m.eval)
 222           ) {
 223             m.eval = mvEval;
 224             m.next = m2;
 225           }
 226           this.undo(m2);
 227         });
 228       }
 229       else {
 230         const score = this.getCurrentScore();
 231         if (score != "1/2") {
 232           if (score != "*") m.eval = (score == "1-0" ? 1 : -1) * maxeval;
 233           else m.eval = this.evalPosition();
 234         }
 235       }
 236       this.undo(m);
 237     });
 238     moves.sort((a, b) => {
 239       return (color == "w" ? 1 : -1) * (b.eval - a.eval);
 240     });
 241     let candidates = [0];
 242     for (let i = 1; i < moves.length && moves[i].eval == moves[0].eval; i++)
 243       candidates.push(i);
 244     const mIdx = candidates[randInt(candidates.length)];
 245     if (!moves[mIdx].next) return moves[mIdx];
 246     const move2 = moves[mIdx].next;
 247     delete moves[mIdx]["next"];
 248     return [moves[mIdx], move2];
 249   }
 250
 251   getNotation(move) {
 252     if (move.vanish.length > 0) return super.getNotation(move);
 253     // Replacement:
 254     const piece =
 255       move.appear[0].p != V.PAWN ? move.appear[0].p.toUpperCase() : "";
 256     return piece + "@" + V.CoordsToSquare(move.end);
 257   }
 258
 259 };