client/src/variants/Antiking.js

   1 import { ChessRules } from "@/base_rules";
   2 import { ArrayFun } from "@/utils/array";
   3 import { randInt } from "@/utils/alea";
   4
   5 export const VariantRules = class AntikingRules extends ChessRules {
   6   static get ANTIKING() {
   7     return "a";
   8   }
   9
  10   static get PIECES() {
  11     return ChessRules.PIECES.concat([V.ANTIKING]);
  12   }
  13
  14   getPpath(b) {
  15     return b[1] == "a" ? "Antiking/" + b : b;
  16   }
  17
  18   setOtherVariables(fen) {
  19     super.setOtherVariables(fen);
  20     this.antikingPos = { w: [-1, -1], b: [-1, -1] };
  21     const rows = V.ParseFen(fen).position.split("/");
  22     for (let i = 0; i < rows.length; i++) {
  23       let k = 0;
  24       for (let j = 0; j < rows[i].length; j++) {
  25         switch (rows[i].charAt(j)) {
  26           case "a":
  27             this.antikingPos["b"] = [i, k];
  28             break;
  29           case "A":
  30             this.antikingPos["w"] = [i, k];
  31             break;
  32           default: {
  33             const num = parseInt(rows[i].charAt(j));
  34             if (!isNaN(num)) k += num - 1;
  35           }
  36         }
  37         k++;
  38       }
  39     }
  40   }
  41
  42   canTake([x1, y1], [x2, y2]) {
  43     const piece1 = this.getPiece(x1, y1);
  44     const piece2 = this.getPiece(x2, y2);
  45     const color1 = this.getColor(x1, y1);
  46     const color2 = this.getColor(x2, y2);
  47     return (
  48       piece2 != "a" &&
  49       ((piece1 != "a" && color1 != color2) ||
  50         (piece1 == "a" && color1 == color2))
  51     );
  52   }
  53
  54   getPotentialMovesFrom([x, y]) {
  55     switch (this.getPiece(x, y)) {
  56       case V.ANTIKING:
  57         return this.getPotentialAntikingMoves([x, y]);
  58       default:
  59         return super.getPotentialMovesFrom([x, y]);
  60     }
  61   }
  62
  63   getPotentialAntikingMoves(sq) {
  64     return this.getSlideNJumpMoves(
  65       sq,
  66       V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
  67       "oneStep"
  68     );
  69   }
  70
  71   isAttacked(sq, color) {
  72     return (
  73       super.isAttacked(sq, color) ||
  74       this.isAttackedByAntiking(sq, color)
  75     );
  76   }
  77
  78   isAttackedByKing([x, y], color) {
  79     // Antiking is not attacked by king:
  80     if (this.getPiece(x, y) == V.ANTIKING) return false;
  81     return this.isAttackedBySlideNJump(
  82       [x, y],
  83       color,
  84       V.KING,
  85       V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
  86       "oneStep"
  87     );
  88   }
  89
  90   isAttackedByAntiking([x, y], color) {
  91     // (Anti)King is not attacked by antiking
  92     if ([V.KING, V.ANTIKING].includes(this.getPiece(x, y))) return false;
  93     return this.isAttackedBySlideNJump(
  94       [x, y],
  95       color,
  96       V.ANTIKING,
  97       V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
  98       "oneStep"
  99     );
 100   }
 101
 102   underCheck(color) {
 103     const oppCol = V.GetOppCol(color);
 104     let res =
 105       this.isAttacked(this.kingPos[color], oppCol) ||
 106       !this.isAttacked(this.antikingPos[color], oppCol);
 107     return res;
 108   }
 109
 110   getCheckSquares(color) {
 111     let res = super.getCheckSquares(color);
 112     if (!this.isAttacked(this.antikingPos[color], V.GetOppCol(color)))
 113       res.push(JSON.parse(JSON.stringify(this.antikingPos[color])));
 114     return res;
 115   }
 116
 117   postPlay(move) {
 118     super.postPlay(move);
 119     const piece = move.vanish[0].p;
 120     const c = move.vanish[0].c;
 121     // Update antiking position
 122     if (piece == V.ANTIKING) {
 123       this.antikingPos[c][0] = move.appear[0].x;
 124       this.antikingPos[c][1] = move.appear[0].y;
 125     }
 126   }
 127
 128   postUndo(move) {
 129     super.postUndo(move);
 130     const c = move.vanish[0].c;
 131     if (move.vanish[0].p == V.ANTIKING)
 132       this.antikingPos[c] = [move.start.x, move.start.y];
 133   }
 134
 135   getCurrentScore() {
 136     if (this.atLeastOneMove())
 137       return "*";
 138
 139     const color = this.turn;
 140     const oppCol = V.GetOppCol(color);
 141     if (
 142       !this.isAttacked(this.kingPos[color], oppCol) &&
 143       this.isAttacked(this.antikingPos[color], oppCol)
 144     ) {
 145       return "1/2";
 146     }
 147     return color == "w" ? "0-1" : "1-0";
 148   }
 149
 150   static get VALUES() {
 151     return Object.assign(
 152       { a: 1000 },
 153       ChessRules.VALUES
 154     );
 155   }
 156
 157   static GenRandInitFen(randomness) {
 158     if (randomness == 0)
 159       return "rnbqkbnr/pppppppp/3A4/8/8/3a4/PPPPPPPP/RNBQKBNR w 0 ahah -";
 160
 161     let pieces = { w: new Array(8), b: new Array(8) };
 162     let flags = "";
 163     let antikingPos = { w: -1, b: -1 };
 164     for (let c of ["w", "b"]) {
 165       if (c == 'b' && randomness == 1) {
 166         pieces['b'] = pieces['w'];
 167         antikingPos['b'] = antikingPos['w'];
 168         flags += flags;
 169         break;
 170       }
 171
 172       let positions = ArrayFun.range(8);
 173
 174       // Get random squares for bishops, but avoid corners; because,
 175       // if an antiking blocks a cornered bishop, it can never be checkmated
 176       let randIndex = 2 * randInt(1, 4);
 177       const bishop1Pos = positions[randIndex];
 178       let randIndex_tmp = 2 * randInt(3) + 1;
 179       const bishop2Pos = positions[randIndex_tmp];
 180       positions.splice(Math.max(randIndex, randIndex_tmp), 1);
 181       positions.splice(Math.min(randIndex, randIndex_tmp), 1);
 182
 183       randIndex = randInt(6);
 184       const knight1Pos = positions[randIndex];
 185       positions.splice(randIndex, 1);
 186       randIndex = randInt(5);
 187       const knight2Pos = positions[randIndex];
 188       positions.splice(randIndex, 1);
 189
 190       randIndex = randInt(4);
 191       const queenPos = positions[randIndex];
 192       positions.splice(randIndex, 1);
 193
 194       const rook1Pos = positions[0];
 195       const kingPos = positions[1];
 196       const rook2Pos = positions[2];
 197
 198       // Random squares for antikings
 199       antikingPos[c] = randInt(8);
 200
 201       pieces[c][rook1Pos] = "r";
 202       pieces[c][knight1Pos] = "n";
 203       pieces[c][bishop1Pos] = "b";
 204       pieces[c][queenPos] = "q";
 205       pieces[c][kingPos] = "k";
 206       pieces[c][bishop2Pos] = "b";
 207       pieces[c][knight2Pos] = "n";
 208       pieces[c][rook2Pos] = "r";
 209       flags += V.CoordToColumn(rook1Pos) + V.CoordToColumn(rook2Pos);
 210     }
 211     const ranks23_black =
 212       "pppppppp/" +
 213       (antikingPos["w"] > 0 ? antikingPos["w"] : "") +
 214       "A" +
 215       (antikingPos["w"] < 7 ? 7 - antikingPos["w"] : "");
 216     const ranks23_white =
 217       (antikingPos["b"] > 0 ? antikingPos["b"] : "") +
 218       "a" +
 219       (antikingPos["b"] < 7 ? 7 - antikingPos["b"] : "") +
 220       "/PPPPPPPP";
 221     return (
 222       pieces["b"].join("") +
 223       "/" +
 224       ranks23_black +
 225       "/8/8/" +
 226       ranks23_white +
 227       "/" +
 228       pieces["w"].join("").toUpperCase() +
 229       " w 0 " + flags + " -"
 230     );
 231   }
 232
 233   static get SEARCH_DEPTH() {
 234     return 2;
 235   }
 236 };