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