client/src/variants/Allmate1.js

   1 import { ChessRules, PiPo, Move } from "@/base_rules";
   2
   3 export class Allmate1Rules extends ChessRules {
   4
   5   static get HasEnpassant() {
   6     return false;
   7   }
   8
   9   getCheckSquares() {
  10     // No notion of check
  11     return [];
  12   }
  13
  14   static GenRandInitFen(randomness) {
  15     return ChessRules.GenRandInitFen(randomness).slice(0, -2);
  16   }
  17
  18   getPotentialMovesFrom([x, y]) {
  19     let moves = super.getPotentialMovesFrom([x, y]);
  20     // Remove standard captures (without removing castling):
  21     moves = moves.filter(m => {
  22       return m.vanish.length == 1 || m.appear.length == 2;
  23     });
  24
  25     // Augment moves with "mate-captures":
  26     // TODO: this is coded in a highly inefficient way...
  27     const color = this.turn;
  28     const oppCol = V.GetOppCol(this.turn);
  29     moves.forEach(m => {
  30       this.play(m);
  31       let allAttacks = [];
  32
  33       // While something has been captured:
  34       // remove it, and keep looking for captures
  35       outerLoop: while (true) {
  36
  37         // 1) What is attacked?
  38         let attacked = {};
  39         for (let i=0; i<V.size.x; i++) {
  40           for (let j=0; j<V.size.y; j++) {
  41             if (this.getColor(i,j) == oppCol && this.isAttacked([i,j], color))
  42               attacked[i+"_"+j] = [i,j];
  43           }
  44         }
  45         if (Object.keys(attacked).length == 0) break outerLoop;
  46
  47         // 2) Among attacked pieces, which cannot escape capture?
  48         // Avoid "oppMoves = this.getAllValidMoves();" => infinite recursion
  49         for (let i=0; i<V.size.x; i++) {
  50           for (let j=0; j<V.size.y; j++) {
  51             if (this.getColor(i,j) == oppCol) {
  52               let oppMoves = [];
  53               switch (this.getPiece(i, j)) {
  54                 case V.PAWN:
  55                   oppMoves = this.getPotentialPawnMoves([i, j]);
  56                   break;
  57                 case V.ROOK:
  58                   oppMoves = this.getPotentialRookMoves([i, j]);
  59                   break;
  60                 case V.KNIGHT:
  61                   oppMoves = this.getPotentialKnightMoves([i, j]);
  62                   break;
  63                 case V.BISHOP:
  64                   oppMoves = this.getPotentialBishopMoves([i, j]);
  65                   break;
  66                 case V.QUEEN:
  67                   oppMoves = this.getPotentialQueenMoves([i, j]);
  68                   break;
  69                 case V.KING:
  70                   // Do not allow castling to escape from check
  71                   oppMoves = super.getSlideNJumpMoves(
  72                     [i, j],
  73                     V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
  74                     "oneStep"
  75                   );
  76                   break;
  77               }
  78               for (let om of oppMoves) {
  79                 V.PlayOnBoard(this.board, om);
  80                 Object.values(attacked).forEach(sq => {
  81                   const origSq = [sq[0], sq[1]];
  82                   if (om.start.x == sq[0] && om.start.y == sq[1])
  83                     // Piece moved:
  84                     sq = [om.appear[0].x, om.appear[0].y];
  85                   if (!this.isAttacked(sq, color))
  86                     delete attacked[origSq[0]+"_"+origSq[1]];
  87                 });
  88                 V.UndoOnBoard(this.board, om);
  89                 if (Object.keys(attacked).length == 0)
  90                   // No need to explore more moves
  91                   break outerLoop;
  92               }
  93             }
  94           }
  95         }
  96
  97         // 3) Add mate-captures and remove pieces from board:
  98         Object.keys(attacked).forEach(k => {
  99           allAttacks.push({
 100             sq: attacked[k],
 101             p: this.getPiece(attacked[k][0], attacked[k][1])
 102           });
 103           this.board[attacked[k][0]][attacked[k][1]] = V.EMPTY;
 104         });
 105       }
 106
 107       // Put removed pieces back on board:
 108       allAttacks.forEach(v => {
 109         this.board[v.sq[0]][v.sq[1]] = oppCol + v.p;
 110       });
 111       this.undo(m);
 112       allAttacks.forEach(v => {
 113         m.vanish.push(
 114           new PiPo({
 115             x: v.sq[0],
 116             y: v.sq[1],
 117             c: oppCol,
 118             p: v.p
 119           })
 120         );
 121       });
 122     });
 123
 124     return moves;
 125   }
 126
 127   // No "under check" conditions in castling
 128   getCastleMoves(sq) {
 129     return super.getCastleMoves(sq, null, "castleInCheck");
 130   }
 131
 132   // TODO: allow pieces to "commit suicide"? (Currently yes except king)
 133   filterValid(moves) {
 134     // Remove moves which let the king mate-captured:
 135     if (moves.length == 0) return [];
 136     const color = this.turn;
 137     const oppCol = V.GetOppCol(color);
 138     return moves.filter(m => {
 139       let res = true;
 140       this.play(m);
 141       if (this.underCheck(color)) {
 142         res = false;
 143         const attacked = this.kingPos[color];
 144         // Try to find a move to escape check
 145         // TODO: very inefficient method.
 146         outerLoop: for (let i=0; i<V.size.x; i++) {
 147           for (let j=0; j<V.size.y; j++) {
 148             if (this.getColor(i,j) == color) {
 149               let emoves = [];
 150               // Artficial turn change to "play twice":
 151               this.turn = color;
 152               switch (this.getPiece(i, j)) {
 153                 case V.PAWN:
 154                   emoves = this.getPotentialPawnMoves([i, j]);
 155                   break;
 156                 case V.ROOK:
 157                   emoves = this.getPotentialRookMoves([i, j]);
 158                   break;
 159                 case V.KNIGHT:
 160                   emoves = this.getPotentialKnightMoves([i, j]);
 161                   break;
 162                 case V.BISHOP:
 163                   emoves = this.getPotentialBishopMoves([i, j]);
 164                   break;
 165                 case V.QUEEN:
 166                   emoves = this.getPotentialQueenMoves([i, j]);
 167                   break;
 168                 case V.KING:
 169                   emoves = this.getPotentialKingMoves([i, j]);
 170                   break;
 171               }
 172               this.turn = oppCol;
 173               for (let em of emoves) {
 174                 V.PlayOnBoard(this.board, em);
 175                 let sq = attacked;
 176                 if (em.start.x == attacked[0] && em.start.y == attacked[1])
 177                   // King moved:
 178                   sq = [em.appear[0].x, em.appear[0].y];
 179                 if (!this.isAttacked(sq, oppCol))
 180                   res = true;
 181                 V.UndoOnBoard(this.board, em);
 182                 if (res)
 183                   // No need to explore more moves
 184                   break outerLoop;
 185               }
 186             }
 187           }
 188         }
 189       }
 190       this.undo(m);
 191       return res;
 192     });
 193   }
 194
 195   postPlay(move) {
 196     super.postPlay(move);
 197     if (move.vanish.length >= 2 && move.appear.length == 1) {
 198       for (let i = 1; i<move.vanish.length; i++) {
 199         const v = move.vanish[i];
 200         // Did opponent king disappeared?
 201         if (v.p == V.KING)
 202           this.kingPos[this.turn] = [-1, -1];
 203         // Or maybe a rook?
 204         else if (v.p == V.ROOK) {
 205           if (v.y < this.kingPos[v.c][1])
 206             this.castleFlags[v.c][0] = 8;
 207           else
 208             // v.y > this.kingPos[v.c][1]
 209             this.castleFlags[v.c][1] = 8;
 210         }
 211       }
 212     }
 213   }
 214
 215   preUndo(move) {
 216     super.preUndo(move);
 217     const oppCol = this.turn;
 218     if (move.vanish.length >= 2 && move.appear.length == 1) {
 219       // Did opponent king disappeared?
 220       const psq = move.vanish.find(v => v.p == V.KING && v.c == oppCol)
 221       if (psq)
 222         this.kingPos[psq.c] = [psq.x, psq.y];
 223     }
 224   }
 225
 226   getCurrentScore() {
 227     const color = this.turn;
 228     const kp = this.kingPos[color];
 229     if (kp[0] < 0)
 230       // King disappeared
 231       return color == "w" ? "0-1" : "1-0";
 232     if (this.atLeastOneMove()) return "*";
 233     // Kings still there, no moves:
 234     return "1/2";
 235   }
 236
 237   static get SEARCH_DEPTH() {
 238     return 1;
 239   }
 240
 241   getNotation(move) {
 242     let notation = super.getNotation(move);
 243     // Add a capture mark (not describing what is captured...):
 244     if (move.vanish.length > 1 && move.appear.length == 1) {
 245       if (!!(notation.match(/^[a-h]x/)))
 246         // Pawn capture: remove initial "b" in bxc4 for example
 247         notation = notation.substr(1);
 248       notation = notation.replace("x","") + "X";
 249     }
 250     return notation;
 251   }
 252
 253 };