| 1 | class ExtinctionRules extends ChessRules |
| 2 | { |
| 3 | initVariables(fen) |
| 4 | { |
| 5 | super.initVariables(fen); |
| 6 | const V = VariantRules; |
| 7 | this.material = |
| 8 | { |
| 9 | "w": |
| 10 | { |
| 11 | [V.KING]: 1, |
| 12 | [V.QUEEN]: 1, |
| 13 | [V.ROOK]: 2, |
| 14 | [V.KNIGHT]: 2, |
| 15 | [V.BISHOP]: 2, |
| 16 | [V.PAWN]: 8 |
| 17 | }, |
| 18 | "b": |
| 19 | { |
| 20 | [V.KING]: 1, |
| 21 | [V.QUEEN]: 1, |
| 22 | [V.ROOK]: 2, |
| 23 | [V.KNIGHT]: 2, |
| 24 | [V.BISHOP]: 2, |
| 25 | [V.PAWN]: 8 |
| 26 | } |
| 27 | }; |
| 28 | } |
| 29 | |
| 30 | getPotentialPawnMoves([x,y]) |
| 31 | { |
| 32 | let moves = super.getPotentialPawnMoves([x,y]); |
| 33 | // Add potential promotions into king |
| 34 | const color = this.turn; |
| 35 | const V = VariantRules; |
| 36 | const [sizeX,sizeY] = V.size; |
| 37 | const shift = (color == "w" ? -1 : 1); |
| 38 | const lastRank = (color == "w" ? 0 : sizeX-1); |
| 39 | |
| 40 | if (x+shift == lastRank) |
| 41 | { |
| 42 | // Normal move |
| 43 | if (this.board[x+shift][y] == V.EMPTY) |
| 44 | moves.push(this.getBasicMove([x,y], [x+shift,y], {c:color,p:V.KING})); |
| 45 | // Captures |
| 46 | if (y>0 && this.canTake([x,y], [x+shift,y-1]) |
| 47 | && this.board[x+shift][y-1] != V.EMPTY) |
| 48 | { |
| 49 | moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:color,p:V.KING})); |
| 50 | } |
| 51 | if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1]) |
| 52 | && this.board[x+shift][y+1] != V.EMPTY) |
| 53 | { |
| 54 | moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:color,p:V.KING})); |
| 55 | } |
| 56 | } |
| 57 | |
| 58 | return moves; |
| 59 | } |
| 60 | |
| 61 | // TODO: verify this assertion |
| 62 | atLeastOneMove() |
| 63 | { |
| 64 | return true; //always at least one possible move |
| 65 | } |
| 66 | |
| 67 | underCheck(move) |
| 68 | { |
| 69 | return false; //there is no check |
| 70 | } |
| 71 | |
| 72 | getCheckSquares(move) |
| 73 | { |
| 74 | return []; |
| 75 | } |
| 76 | |
| 77 | updateVariables(move) |
| 78 | { |
| 79 | super.updateVariables(move); |
| 80 | // Treat the promotion case: (not the capture part) |
| 81 | if (move.appear[0].p != move.vanish[0].p) |
| 82 | { |
| 83 | this.material[move.appear[0].c][move.appear[0].p]++; |
| 84 | this.material[move.appear[0].c][VariantRules.PAWN]--; |
| 85 | } |
| 86 | if (move.vanish.length==2 && move.appear.length==1) //capture |
| 87 | this.material[move.vanish[1].c][move.vanish[1].p]--; |
| 88 | } |
| 89 | |
| 90 | unupdateVariables(move) |
| 91 | { |
| 92 | super.unupdateVariables(move); |
| 93 | if (move.appear[0].p != move.vanish[0].p) |
| 94 | { |
| 95 | this.material[move.appear[0].c][move.appear[0].p]--; |
| 96 | this.material[move.appear[0].c][VariantRules.PAWN]++; |
| 97 | } |
| 98 | if (move.vanish.length==2 && move.appear.length==1) |
| 99 | this.material[move.vanish[1].c][move.vanish[1].p]++; |
| 100 | } |
| 101 | |
| 102 | checkGameOver() |
| 103 | { |
| 104 | if (this.checkRepetition()) |
| 105 | return "1/2"; |
| 106 | |
| 107 | if (this.atLeastOneMove()) // game not over? |
| 108 | { |
| 109 | const color = this.turn; |
| 110 | if (Object.keys(this.material[color]).some( |
| 111 | p => { return this.material[color][p] == 0; })) |
| 112 | { |
| 113 | return this.checkGameEnd(); |
| 114 | } |
| 115 | return "*"; |
| 116 | } |
| 117 | |
| 118 | return this.checkGameEnd(); //NOTE: currently unreachable... |
| 119 | } |
| 120 | |
| 121 | checkGameEnd() |
| 122 | { |
| 123 | return this.turn == "w" ? "0-1" : "1-0"; |
| 124 | } |
| 125 | |
| 126 | evalPosition() |
| 127 | { |
| 128 | const color = this.turn; |
| 129 | if (Object.keys(this.material[color]).some( |
| 130 | p => { return this.material[color][p] == 0; })) |
| 131 | { |
| 132 | // Very negative (resp. positive) if white (reps. black) pieces set is incomplete |
| 133 | return (color=="w"?-1:1) * VariantRules.INFINITY; |
| 134 | } |
| 135 | return super.evalPosition(); |
| 136 | } |
| 137 | } |