client/src/variants/Allmate1.js

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