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
  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       // Avoid "oppMoves = this.getAllValidMoves();" => infinite recursion
  42       outerLoop: for (let i=0; i<V.size.x; i++) {
  43         for (let j=0; j<V.size.y; j++) {
  44           if (this.getColor(i,j) == oppCol) {
  45             let oppMoves = [];
  46             switch (this.getPiece(i, j)) {
  47               case V.PAWN:
  48                 oppMoves = this.getPotentialPawnMoves([i, j]);
  49                 break;
  50               case V.ROOK:
  51                 oppMoves = this.getPotentialRookMoves([i, j]);
  52                 break;
  53               case V.KNIGHT:
  54                 oppMoves = this.getPotentialKnightMoves([i, j]);
  55                 break;
  56               case V.BISHOP:
  57                 oppMoves = this.getPotentialBishopMoves([i, j]);
  58                 break;
  59               case V.QUEEN:
  60                 oppMoves = this.getPotentialQueenMoves([i, j]);
  61                 break;
  62               case V.KING:
  63                 oppMoves = this.getPotentialKingMoves([i, j]);
  64                 break;
  65             }
  66             for (let om of oppMoves) {
  67               V.PlayOnBoard(this.board, om);
  68               Object.values(attacked).forEach(sq => {
  69                 const origSq = [sq[0], sq[1]];
  70                 if (om.start.x == sq[0] && om.start.y == sq[1])
  71                   // Piece moved:
  72                   sq = [om.appear[0].x, om.appear[0].y];
  73                 if (!this.isAttacked(sq, color))
  74                   delete attacked[origSq[0]+"_"+origSq[1]];
  75               });
  76               V.UndoOnBoard(this.board, om);
  77               if (Object.keys(attacked).length == 0)
  78                 // No need to explore more moves
  79                 break outerLoop;
  80             }
  81           }
  82         }
  83       }
  84
  85       // 3) Add mate-captures:
  86       Object.values(attacked).forEach(sq => {
  87         m.vanish.push(new PiPo({
  88           x: sq[0],
  89           y: sq[1],
  90           c: oppCol,
  91           p: this.getPiece(sq[0], sq[1])
  92         }));
  93       });
  94
  95       this.undo(m);
  96     });
  97
  98     return moves;
  99   }
 100
 101   // No "under check" conditions in castling
 102   getCastleMoves(sq) {
 103     return super.getCastleMoves(sq, "castleInCheck");
 104   }
 105
 106   // TODO: allow pieces to "commit suicide"? (Currently yes except king)
 107   filterValid(moves) {
 108     // Remove moves which let the king mate-captured:
 109     if (moves.length == 0) return [];
 110     const color = this.turn;
 111     const oppCol = V.GetOppCol(color);
 112     return moves.filter(m => {
 113       let res = true;
 114       this.play(m);
 115       if (this.underCheck(color)) {
 116         res = false;
 117         const attacked = this.kingPos[color];
 118         // Try to find a move to escape check
 119         // TODO: very inefficient method.
 120         outerLoop: for (let i=0; i<V.size.x; i++) {
 121           for (let j=0; j<V.size.y; j++) {
 122             if (this.getColor(i,j) == color) {
 123               let emoves = [];
 124               // Artficial turn change to "play twice":
 125               this.turn = color;
 126               switch (this.getPiece(i, j)) {
 127                 case V.PAWN:
 128                   emoves = this.getPotentialPawnMoves([i, j]);
 129                   break;
 130                 case V.ROOK:
 131                   emoves = this.getPotentialRookMoves([i, j]);
 132                   break;
 133                 case V.KNIGHT:
 134                   emoves = this.getPotentialKnightMoves([i, j]);
 135                   break;
 136                 case V.BISHOP:
 137                   emoves = this.getPotentialBishopMoves([i, j]);
 138                   break;
 139                 case V.QUEEN:
 140                   emoves = this.getPotentialQueenMoves([i, j]);
 141                   break;
 142                 case V.KING:
 143                   emoves = this.getPotentialKingMoves([i, j]);
 144                   break;
 145               }
 146               this.turn = oppCol;
 147               for (let em of emoves) {
 148                 V.PlayOnBoard(this.board, em);
 149                 let sq = attacked;
 150                 if (em.start.x == attacked[0] && em.start.y == attacked[1])
 151                   // King moved:
 152                   sq = [em.appear[0].x, em.appear[0].y];
 153                 if (!this.isAttacked(sq, oppCol))
 154                   res = true;
 155                 V.UndoOnBoard(this.board, em);
 156                 if (res)
 157                   // No need to explore more moves
 158                   break outerLoop;
 159               }
 160             }
 161           }
 162         }
 163       }
 164       this.undo(m);
 165       return res;
 166     });
 167   }
 168
 169   postPlay(move) {
 170     super.postPlay(move);
 171     if (move.vanish.length >= 2 && move.appear.length == 1) {
 172       for (let i = 1; i<move.vanish.length; i++) {
 173         const v = move.vanish[i];
 174         // Did opponent king disappeared?
 175         if (v.p == V.KING)
 176           this.kingPos[this.turn] = [-1, -1];
 177         // Or maybe a rook?
 178         else if (v.p == V.ROOK) {
 179           if (v.y < this.INIT_COL_KING[v.c])
 180             this.castleFlags[v.c][0] = 8;
 181           else
 182             // v.y > this.INIT_COL_KING[v.c]
 183             this.castleFlags[v.c][1] = 8;
 184         }
 185       }
 186     }
 187   }
 188
 189   preUndo(move) {
 190     super.preUndo(move);
 191     const oppCol = this.turn;
 192     if (move.vanish.length >= 2 && move.appear.length == 1) {
 193       // Did opponent king disappeared?
 194       const psq = move.vanish.find(v => v.p == V.KING && v.c == oppCol)
 195       if (psq)
 196         this.kingPos[psq.c] = [psq.x, psq.y];
 197     }
 198   }
 199
 200   getCurrentScore() {
 201     const color = this.turn;
 202     const kp = this.kingPos[color];
 203     if (kp[0] < 0)
 204       // King disappeared
 205       return color == "w" ? "0-1" : "1-0";
 206     if (this.atLeastOneMove())
 207       return "*";
 208     // Kings still there, no moves:
 209     return "1/2";
 210   }
 211
 212   static get SEARCH_DEPTH() {
 213     return 1;
 214   }
 215
 216   getNotation(move) {
 217     let notation = super.getNotation(move);
 218     // Add a capture mark (not describing what is captured...):
 219     if (move.vanish.length > 1 && move.appear.length == 1) {
 220       if (!!(notation.match(/^[a-h]x/)))
 221         // Pawn capture: remove initial "b" in bxc4 for example
 222         notation = notation.substr(1);
 223       notation = notation.replace("x","") + "X";
 224     }
 225     return notation;
 226   }
 227 };