| 1 | import { ChessRules } from "@/base_rules"; |
| 2 | |
| 3 | export class Knightrelay1Rules extends ChessRules { |
| 4 | static get HasEnpassant() { |
| 5 | return false; |
| 6 | } |
| 7 | |
| 8 | // TODO: IsGoodPosition to check that 2 knights are on the board... |
| 9 | |
| 10 | getPotentialMovesFrom([x, y]) { |
| 11 | let moves = super.getPotentialMovesFrom([x, y]); |
| 12 | |
| 13 | // Expand possible moves if guarded by a knight, and is not a king: |
| 14 | const piece = this.getPiece(x,y); |
| 15 | if (![V.KNIGHT,V.KING].includes(piece)) { |
| 16 | const color = this.turn; |
| 17 | let guardedByKnight = false; |
| 18 | for (const step of V.steps[V.KNIGHT]) { |
| 19 | if ( |
| 20 | V.OnBoard(x+step[0],y+step[1]) && |
| 21 | this.getPiece(x+step[0],y+step[1]) == V.KNIGHT && |
| 22 | this.getColor(x+step[0],y+step[1]) == color |
| 23 | ) { |
| 24 | guardedByKnight = true; |
| 25 | break; |
| 26 | } |
| 27 | } |
| 28 | if (guardedByKnight) { |
| 29 | const lastRank = (color == "w" ? 0 : V.size.x - 1); |
| 30 | for (const step of V.steps[V.KNIGHT]) { |
| 31 | if ( |
| 32 | V.OnBoard(x+step[0],y+step[1]) && |
| 33 | this.getColor(x+step[0],y+step[1]) != color && |
| 34 | // Pawns cannot promote by knight-relay |
| 35 | (piece != V.PAWN || x+step[0] != lastRank) |
| 36 | ) { |
| 37 | moves.push(this.getBasicMove([x,y], [x+step[0],y+step[1]])); |
| 38 | } |
| 39 | } |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | // Forbid captures of knights (invincible in this variant) |
| 44 | return moves.filter(m => { |
| 45 | return ( |
| 46 | m.vanish.length == 1 || |
| 47 | m.appear.length == 2 || |
| 48 | m.vanish[1].p != V.KNIGHT |
| 49 | ); |
| 50 | }); |
| 51 | } |
| 52 | |
| 53 | getPotentialKnightMoves(sq) { |
| 54 | // Knights don't capture: |
| 55 | return super.getPotentialKnightMoves(sq).filter(m => m.vanish.length == 1); |
| 56 | } |
| 57 | |
| 58 | isAttacked(sq, color) { |
| 59 | if (super.isAttacked(sq, color)) return true; |
| 60 | |
| 61 | // Check if a (non-knight) piece at knight distance |
| 62 | // is guarded by a knight (and thus attacking) |
| 63 | // --> Except for pawns targetting last rank. |
| 64 | const x = sq[0], |
| 65 | y = sq[1]; |
| 66 | // Last rank for me, that is to say oppCol of color: |
| 67 | const lastRank = (color == 'w' ? V.size.x - 1 : 0); |
| 68 | for (const step of V.steps[V.KNIGHT]) { |
| 69 | if ( |
| 70 | V.OnBoard(x+step[0],y+step[1]) && |
| 71 | this.getColor(x+step[0],y+step[1]) == color |
| 72 | ) { |
| 73 | const piece = this.getPiece(x+step[0],y+step[1]); |
| 74 | if (piece != V.KNIGHT && (piece != V.PAWN || x != lastRank)) { |
| 75 | for (const step2 of V.steps[V.KNIGHT]) { |
| 76 | const xx = x+step[0]+step2[0], |
| 77 | yy = y+step[1]+step2[1]; |
| 78 | if ( |
| 79 | V.OnBoard(xx,yy) && |
| 80 | this.getColor(xx,yy) == color && |
| 81 | this.getPiece(xx,yy) == V.KNIGHT |
| 82 | ) { |
| 83 | return true; |
| 84 | } |
| 85 | } |
| 86 | } |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | return false; |
| 91 | } |
| 92 | |
| 93 | isAttackedByKnight(sq, color) { |
| 94 | // Knights don't attack |
| 95 | return false; |
| 96 | } |
| 97 | |
| 98 | static get VALUES() { |
| 99 | return { |
| 100 | p: 1, |
| 101 | r: 5, |
| 102 | n: 0, //the knight isn't captured - value doesn't matter |
| 103 | b: 3, |
| 104 | q: 9, |
| 105 | k: 1000 |
| 106 | }; |
| 107 | } |
| 108 | |
| 109 | static get SEARCH_DEPTH() { |
| 110 | return 2; |
| 111 | } |
| 112 | |
| 113 | getNotation(move) { |
| 114 | if (move.appear.length == 2 && move.appear[0].p == V.KING) |
| 115 | // Castle |
| 116 | return move.end.y < move.start.y ? "0-0-0" : "0-0"; |
| 117 | |
| 118 | // Translate final and initial square |
| 119 | const initSquare = V.CoordsToSquare(move.start); |
| 120 | const finalSquare = V.CoordsToSquare(move.end); |
| 121 | const piece = this.getPiece(move.start.x, move.start.y); |
| 122 | |
| 123 | // Since pieces and pawns could move like knight, |
| 124 | // indicate start and end squares |
| 125 | let notation = |
| 126 | piece.toUpperCase() + |
| 127 | initSquare + |
| 128 | (move.vanish.length > move.appear.length ? "x" : "") + |
| 129 | finalSquare |
| 130 | |
| 131 | if ( |
| 132 | piece == V.PAWN && |
| 133 | move.appear.length > 0 && |
| 134 | move.appear[0].p != V.PAWN |
| 135 | ) { |
| 136 | // Promotion |
| 137 | notation += "=" + move.appear[0].p.toUpperCase(); |
| 138 | } |
| 139 | |
| 140 | return notation; |
| 141 | } |
| 142 | }; |