| 1 | class LoserRules extends ChessRules |
| 2 | { |
| 3 | initVariables(fen) |
| 4 | { |
| 5 | const epSq = this.moves.length > 0 ? this.getEpSquare(this.lastMove) : undefined; |
| 6 | this.epSquares = [ epSq ]; |
| 7 | } |
| 8 | |
| 9 | setFlags(fen) |
| 10 | { |
| 11 | // No castling, hence no flags; but flags defined for compatibility |
| 12 | this.castleFlags = "0000"; |
| 13 | } |
| 14 | |
| 15 | getPotentialPawnMoves([x,y]) |
| 16 | { |
| 17 | let moves = super.getPotentialPawnMoves([x,y]); |
| 18 | |
| 19 | // Complete with promotion(s) into king, if possible |
| 20 | const color = this.turn; |
| 21 | const V = VariantRules; |
| 22 | const [sizeX,sizeY] = VariantRules.size; |
| 23 | const shift = (color == "w" ? -1 : 1); |
| 24 | const lastRank = (color == "w" ? 0 : sizeX-1); |
| 25 | if (x+shift == lastRank) |
| 26 | { |
| 27 | let p = V.KING; |
| 28 | // Normal move |
| 29 | if (this.board[x+shift][y] == V.EMPTY) |
| 30 | moves.push(this.getBasicMove([x,y], [x+shift,y], {c:color,p:p})); |
| 31 | // Captures |
| 32 | if (y>0 && this.canTake([x,y], [x+shift,y-1]) && this.board[x+shift][y-1] != V.EMPTY) |
| 33 | moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:color,p:p})); |
| 34 | if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1]) && this.board[x+shift][y+1] != V.EMPTY) |
| 35 | moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:color,p:p})); |
| 36 | } |
| 37 | |
| 38 | return moves; |
| 39 | } |
| 40 | |
| 41 | getPotentialKingMoves(sq) |
| 42 | { |
| 43 | const V = VariantRules; |
| 44 | return this.getSlideNJumpMoves(sq, |
| 45 | V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep"); |
| 46 | } |
| 47 | |
| 48 | // Stop at the first capture found (if any) |
| 49 | atLeastOneCapture() |
| 50 | { |
| 51 | const color = this.turn; |
| 52 | const oppCol = this.getOppCol(color); |
| 53 | const [sizeX,sizeY] = VariantRules.size; |
| 54 | for (let i=0; i<sizeX; i++) |
| 55 | { |
| 56 | for (let j=0; j<sizeY; j++) |
| 57 | { |
| 58 | if (this.board[i][j] != VariantRules.EMPTY && this.getColor(i,j) != oppCol) |
| 59 | { |
| 60 | const moves = this.getPotentialMovesFrom([i,j]); |
| 61 | if (moves.length > 0) |
| 62 | { |
| 63 | for (let k=0; k<moves.length; k++) |
| 64 | { |
| 65 | if (moves[k].vanish.length==2 && this.filterValid([moves[k]]).length > 0) |
| 66 | return true; |
| 67 | } |
| 68 | } |
| 69 | } |
| 70 | } |
| 71 | } |
| 72 | return false; |
| 73 | } |
| 74 | |
| 75 | // Trim all non-capturing moves |
| 76 | static KeepCaptures(moves) |
| 77 | { |
| 78 | return moves.filter(m => { return m.vanish.length == 2; }); |
| 79 | } |
| 80 | |
| 81 | getPossibleMovesFrom(sq) |
| 82 | { |
| 83 | let moves = this.filterValid( this.getPotentialMovesFrom(sq) ); |
| 84 | // This is called from interface: we need to know if a capture is possible |
| 85 | if (this.atLeastOneCapture()) |
| 86 | moves = VariantRules.KeepCaptures(moves); |
| 87 | return moves; |
| 88 | } |
| 89 | |
| 90 | getAllValidMoves() |
| 91 | { |
| 92 | let moves = super.getAllValidMoves(); |
| 93 | if (moves.some(m => { return m.vanish.length == 2; })) |
| 94 | moves = VariantRules.KeepCaptures(moves); |
| 95 | return moves; |
| 96 | } |
| 97 | |
| 98 | underCheck(move) |
| 99 | { |
| 100 | return false; //No notion of check |
| 101 | } |
| 102 | |
| 103 | getCheckSquares(move) |
| 104 | { |
| 105 | return []; |
| 106 | } |
| 107 | |
| 108 | // Unused: |
| 109 | updateVariables(move) { } |
| 110 | unupdateVariables(move) { } |
| 111 | parseFlags(flags) { } |
| 112 | |
| 113 | checkGameEnd() |
| 114 | { |
| 115 | // No valid move: you win! |
| 116 | return this.turn == "w" ? "1-0" : "0-1"; |
| 117 | } |
| 118 | |
| 119 | static get VALUES() { //experimental... |
| 120 | return { |
| 121 | 'p': 1, |
| 122 | 'r': 7, |
| 123 | 'n': 3, |
| 124 | 'b': 3, |
| 125 | 'q': 5, |
| 126 | 'k': 5 |
| 127 | }; |
| 128 | } |
| 129 | |
| 130 | static get SEARCH_DEPTH() { return 4; } |
| 131 | |
| 132 | evalPosition() |
| 133 | { |
| 134 | return - super.evalPosition(); //better with less material |
| 135 | } |
| 136 | } |