client/src/variants/Allmate2.js

   1 import { ChessRules, PiPo, Move } from "@/base_rules";
   2
   3 export class Allmate2Rules 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
  31       // 1) What is attacked?
  32       let attacked = {};
  33       for (let i=0; i<V.size.x; i++) {
  34         for (let j=0; j<V.size.y; j++) {
  35           if (this.getColor(i,j) == oppCol && this.isAttacked([i,j], color))
  36             attacked[i+"_"+j] = [i,j];
  37         }
  38       }
  39
  40       // 2) Among attacked pieces, which cannot escape capture?
  41       // --> without (normal-)capturing: difference with Allmate1 variant
  42       // Avoid "oppMoves = this.getAllValidMoves();" => infinite recursion
  43       outerLoop: for (let i=0; i<V.size.x; i++) {
  44         for (let j=0; j<V.size.y; j++) {
  45           if (this.getColor(i,j) == oppCol) {
  46             let oppMoves = [];
  47             switch (this.getPiece(i, j)) {
  48               case V.PAWN:
  49                 oppMoves = this.getPotentialPawnMoves([i, j]);
  50                 break;
  51               case V.ROOK:
  52                 oppMoves = this.getPotentialRookMoves([i, j]);
  53                 break;
  54               case V.KNIGHT:
  55                 oppMoves = this.getPotentialKnightMoves([i, j]);
  56                 break;
  57               case V.BISHOP:
  58                 oppMoves = this.getPotentialBishopMoves([i, j]);
  59                 break;
  60               case V.QUEEN:
  61                 oppMoves = this.getPotentialQueenMoves([i, j]);
  62                 break;
  63               case V.KING:
  64                 oppMoves = this.getPotentialKingMoves([i, j]);
  65                 break;
  66             }
  67             for (let om of oppMoves) {
  68               if (om.vanish.length == 2 && om.appear.length == 1)
  69                 // Skip captures: forbidden in this mode
  70                 continue;
  71               V.PlayOnBoard(this.board, om);
  72               Object.values(attacked).forEach(sq => {
  73                 const origSq = [sq[0], sq[1]];
  74                 if (om.start.x == sq[0] && om.start.y == sq[1])
  75                   // Piece moved:
  76                   sq = [om.appear[0].x, om.appear[0].y];
  77                 if (!this.isAttacked(sq, color))
  78                   delete attacked[origSq[0]+"_"+origSq[1]];
  79               });
  80               V.UndoOnBoard(this.board, om);
  81               if (Object.keys(attacked).length == 0)
  82                 // No need to explore more moves
  83                 break outerLoop;
  84             }
  85           }
  86         }
  87       }
  88
  89       // 3) Add mate-captures:
  90       Object.values(attacked).forEach(sq => {
  91         m.vanish.push(new PiPo({
  92           x: sq[0],
  93           y: sq[1],
  94           c: oppCol,
  95           p: this.getPiece(sq[0], sq[1])
  96         }));
  97       });
  98
  99       this.undo(m);
 100     });
 101
 102     return moves;
 103   }
 104
 105   // No "under check" conditions in castling
 106   getCastleMoves(sq) {
 107     return super.getCastleMoves(sq, "castleInCheck");
 108   }
 109
 110   // TODO: allow pieces to "commit suicide"? (Currently yes except king)
 111   filterValid(moves) {
 112     // Remove moves which let the king mate-captured:
 113     if (moves.length == 0) return [];
 114     const color = this.turn;
 115     const oppCol = V.GetOppCol(color);
 116     return moves.filter(m => {
 117       let res = true;
 118       this.play(m);
 119       if (this.underCheck(color)) {
 120         res = false;
 121         const attacked = this.kingPos[color];
 122         // Try to find a move to escape check
 123         // TODO: very inefficient method.
 124         outerLoop: for (let i=0; i<V.size.x; i++) {
 125           for (let j=0; j<V.size.y; j++) {
 126             if (this.getColor(i,j) == color) {
 127               let emoves = [];
 128               // Artficial turn change to "play twice":
 129               this.turn = color;
 130               switch (this.getPiece(i, j)) {
 131                 case V.PAWN:
 132                   emoves = this.getPotentialPawnMoves([i, j]);
 133                   break;
 134                 case V.ROOK:
 135                   emoves = this.getPotentialRookMoves([i, j]);
 136                   break;
 137                 case V.KNIGHT:
 138                   emoves = this.getPotentialKnightMoves([i, j]);
 139                   break;
 140                 case V.BISHOP:
 141                   emoves = this.getPotentialBishopMoves([i, j]);
 142                   break;
 143                 case V.QUEEN:
 144                   emoves = this.getPotentialQueenMoves([i, j]);
 145                   break;
 146                 case V.KING:
 147                   emoves = this.getPotentialKingMoves([i, j]);
 148                   break;
 149               }
 150               this.turn = oppCol;
 151               for (let em of emoves) {
 152                 V.PlayOnBoard(this.board, em);
 153                 let sq = attacked;
 154                 if (em.start.x == attacked[0] && em.start.y == attacked[1])
 155                   // King moved:
 156                   sq = [em.appear[0].x, em.appear[0].y];
 157                 if (!this.isAttacked(sq, oppCol))
 158                   res = true;
 159                 V.UndoOnBoard(this.board, em);
 160                 if (res)
 161                   // No need to explore more moves
 162                   break outerLoop;
 163               }
 164             }
 165           }
 166         }
 167       }
 168       this.undo(m);
 169       return res;
 170     });
 171   }
 172
 173   postPlay(move) {
 174     super.postPlay(move);
 175     if (move.vanish.length >= 2 && move.appear.length == 1) {
 176       for (let i = 1; i<move.vanish.length; i++) {
 177         const v = move.vanish[i];
 178         // Did opponent king disappeared?
 179         if (v.p == V.KING)
 180           this.kingPos[this.turn] = [-1, -1];
 181         // Or maybe a rook?
 182         else if (v.p == V.ROOK) {
 183           if (v.y < this.INIT_COL_KING[v.c])
 184             this.castleFlags[v.c][0] = 8;
 185           else
 186             // v.y > this.INIT_COL_KING[v.c]
 187             this.castleFlags[v.c][1] = 8;
 188         }
 189       }
 190     }
 191   }
 192
 193   preUndo(move) {
 194     super.preUndo(move);
 195     const oppCol = this.turn;
 196     if (move.vanish.length >= 2 && move.appear.length == 1) {
 197       // Did opponent king disappeared?
 198       const psq = move.vanish.find(v => v.p == V.KING && v.c == oppCol)
 199       if (psq)
 200         this.kingPos[psq.c] = [psq.x, psq.y];
 201     }
 202   }
 203
 204   getCurrentScore() {
 205     const color = this.turn;
 206     const kp = this.kingPos[color];
 207     if (kp[0] < 0)
 208       // King disappeared
 209       return color == "w" ? "0-1" : "1-0";
 210     if (this.atLeastOneMove())
 211       return "*";
 212     // Kings still there, no moves:
 213     return "1/2";
 214   }
 215
 216   static get SEARCH_DEPTH() {
 217     return 1;
 218   }
 219
 220   getNotation(move) {
 221     let notation = super.getNotation(move);
 222     // Add a capture mark (not describing what is captured...):
 223     if (move.vanish.length > 1 && move.appear.length == 1) {
 224       if (!!(notation.match(/^[a-h]x/)))
 225         // Pawn capture: remove initial "b" in bxc4 for example
 226         notation = notation.substr(1);
 227       notation = notation.replace("x","") + "X";
 228     }
 229     return notation;
 230   }
 231 };