client/src/variants/Antiking2.js

   1 import { ChessRules } from "@/base_rules";
   2 import { ArrayFun } from "@/utils/array";
   3 import { randInt } from "@/utils/alea";
   4
   5 export class Antiking2Rules extends ChessRules {
   6
   7   static get ANTIKING() {
   8     return "a";
   9   }
  10
  11   static get PIECES() {
  12     return ChessRules.PIECES.concat([V.ANTIKING]);
  13   }
  14
  15   getPpath(b) {
  16     return b[1] == "a" ? "Antiking/" + b : b;
  17   }
  18
  19   static IsGoodPosition(position) {
  20     if (!ChessRules.IsGoodPosition(position)) return false;
  21     const rows = position.split("/");
  22     // Check that exactly one antiking of each color is there:
  23     let antikings = { 'a': 0, 'A': 0 };
  24     for (let row of rows) {
  25       for (let i = 0; i < row.length; i++)
  26         if (['A','a'].includes(row[i])) antikings[row[i]]++;
  27     }
  28     if (Object.values(antikings).some(v => v != 1)) return false;
  29     return true;
  30   }
  31
  32   setOtherVariables(fen) {
  33     super.setOtherVariables(fen);
  34     this.antikingPos = { w: [-1, -1], b: [-1, -1] };
  35     const rows = V.ParseFen(fen).position.split("/");
  36     for (let i = 0; i < rows.length; i++) {
  37       let k = 0;
  38       for (let j = 0; j < rows[i].length; j++) {
  39         switch (rows[i].charAt(j)) {
  40           case "a":
  41             this.antikingPos["b"] = [i, k];
  42             break;
  43           case "A":
  44             this.antikingPos["w"] = [i, k];
  45             break;
  46           default: {
  47             const num = parseInt(rows[i].charAt(j), 10);
  48             if (!isNaN(num)) k += num - 1;
  49           }
  50         }
  51         k++;
  52       }
  53     }
  54   }
  55
  56   canTake([x1, y1], [x2, y2]) {
  57     const piece1 = this.getPiece(x1, y1);
  58     const piece2 = this.getPiece(x2, y2);
  59     const color1 = this.getColor(x1, y1);
  60     const color2 = this.getColor(x2, y2);
  61     return (
  62       piece2 != "a" &&
  63       (
  64         (piece1 != "a" && color1 != color2) ||
  65         (piece1 == "a" && color1 == color2)
  66       )
  67     );
  68   }
  69
  70   getPotentialMovesFrom([x, y]) {
  71     switch (this.getPiece(x, y)) {
  72       case V.ANTIKING:
  73         return this.getPotentialAntikingMoves([x, y]);
  74       default:
  75         return super.getPotentialMovesFrom([x, y]);
  76     }
  77   }
  78
  79   getPotentialAntikingMoves(sq) {
  80     // The antiking moves like a king (only captured colors differ)
  81     return this.getSlideNJumpMoves(
  82       sq,
  83       V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
  84       "oneStep"
  85     );
  86   }
  87
  88   isAttacked(sq, color) {
  89     return (
  90       super.isAttacked(sq, color) ||
  91       this.isAttackedByAntiking(sq, color)
  92     );
  93   }
  94
  95   isAttackedByKing([x, y], color) {
  96     // Antiking is not attacked by king:
  97     if (this.getPiece(x, y) == V.ANTIKING) return false;
  98     return super.isAttackedByKing([x, y], color);
  99   }
 100
 101   isAttackedByAntiking([x, y], color) {
 102     // (Anti)King is not attacked by antiking
 103     if ([V.KING, V.ANTIKING].includes(this.getPiece(x, y))) return false;
 104     return this.isAttackedBySlideNJump(
 105       [x, y],
 106       color,
 107       V.ANTIKING,
 108       V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
 109       "oneStep"
 110     );
 111   }
 112
 113   underCheck(color) {
 114     const oppCol = V.GetOppCol(color);
 115     let res =
 116       this.isAttacked(this.kingPos[color], oppCol) ||
 117       !this.isAttacked(this.antikingPos[color], oppCol);
 118     return res;
 119   }
 120
 121   getCheckSquares() {
 122     const color = this.turn;
 123     let res = [];
 124     const oppCol = V.GetOppCol(color);
 125     if (this.isAttacked(this.kingPos[color], oppCol))
 126       res.push(JSON.parse(JSON.stringify(this.kingPos[color])));
 127     if (!this.isAttacked(this.antikingPos[color], oppCol))
 128       res.push(JSON.parse(JSON.stringify(this.antikingPos[color])));
 129     return res;
 130   }
 131
 132   postPlay(move) {
 133     super.postPlay(move);
 134     const piece = move.vanish[0].p;
 135     const c = move.vanish[0].c;
 136     // Update antiking position
 137     if (piece == V.ANTIKING) {
 138       this.antikingPos[c][0] = move.appear[0].x;
 139       this.antikingPos[c][1] = move.appear[0].y;
 140     }
 141   }
 142
 143   postUndo(move) {
 144     super.postUndo(move);
 145     const c = move.vanish[0].c;
 146     if (move.vanish[0].p == V.ANTIKING)
 147       this.antikingPos[c] = [move.start.x, move.start.y];
 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
 237 };