| 1 | import { ChessRules } from "@/base_rules"; |
| 2 | import { ArrayFun } from "@/utils/array"; |
| 3 | import { randInt } from "@/utils/alea"; |
| 4 | |
| 5 | export const VariantRules = class GrasshopperRules extends ChessRules { |
| 6 | static get GRASSHOPPER() { |
| 7 | return "g"; |
| 8 | } |
| 9 | |
| 10 | static get PIECES() { |
| 11 | return ChessRules.PIECES.concat([V.GRASSHOPPER]); |
| 12 | } |
| 13 | |
| 14 | getPpath(b) { |
| 15 | return (b[1] == V.GRASSHOPPER ? "Grasshopper/" : "") + b; |
| 16 | } |
| 17 | |
| 18 | getPotentialMovesFrom([x, y]) { |
| 19 | switch (this.getPiece(x, y)) { |
| 20 | case V.GRASSHOPPER: |
| 21 | return this.getPotentialGrasshopperMoves([x, y]); |
| 22 | default: |
| 23 | return super.getPotentialMovesFrom([x, y]); |
| 24 | } |
| 25 | } |
| 26 | |
| 27 | getPotentialGrasshopperMoves([x, y]) { |
| 28 | let moves = []; |
| 29 | // Look in every direction until an obstacle (to jump) is met |
| 30 | for (const step of V.steps[V.ROOK].concat(V.steps[V.BISHOP])) { |
| 31 | let i = x + step[0]; |
| 32 | let j = y + step[1]; |
| 33 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { |
| 34 | i += step[0]; |
| 35 | j += step[1]; |
| 36 | } |
| 37 | // Move is valid if the next square is empty or occupied by enemy |
| 38 | const nextSq = [i+step[0], j+step[1]]; |
| 39 | if (V.OnBoard(nextSq[0], nextSq[1]) && this.canTake([x, y], nextSq)) |
| 40 | moves.push(this.getBasicMove([x, y], nextSq)); |
| 41 | } |
| 42 | return moves; |
| 43 | } |
| 44 | |
| 45 | isAttacked(sq, colors) { |
| 46 | return ( |
| 47 | super.isAttacked(sq, colors) || |
| 48 | this.isAttackedByGrasshopper(sq, colors) |
| 49 | ); |
| 50 | } |
| 51 | |
| 52 | isAttackedByGrasshopper([x, y], colors) { |
| 53 | // Reversed process: is there an adjacent obstacle, |
| 54 | // and a grasshopper next in the same line? |
| 55 | for (const step of V.steps[V.ROOK].concat(V.steps[V.BISHOP])) { |
| 56 | const nextSq = [x+step[0], y+step[1]]; |
| 57 | if ( |
| 58 | V.OnBoard(nextSq[0], nextSq[1]) && |
| 59 | this.board[nextSq[0]][nextSq[1]] != V.EMPTY |
| 60 | ) { |
| 61 | let i = nextSq[0] + step[0]; |
| 62 | let j = nextSq[1] + step[1]; |
| 63 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { |
| 64 | i += step[0]; |
| 65 | j += step[1]; |
| 66 | } |
| 67 | if ( |
| 68 | V.OnBoard(i, j) && |
| 69 | this.getPiece(i, j) == V.GRASSHOPPER && |
| 70 | colors.includes(this.getColor(i, j)) |
| 71 | ) { |
| 72 | return true; |
| 73 | } |
| 74 | } |
| 75 | } |
| 76 | return false; |
| 77 | } |
| 78 | |
| 79 | static get VALUES() { |
| 80 | return Object.assign( |
| 81 | // TODO: grasshoppers power decline when less pieces on board... |
| 82 | { g: 3 }, |
| 83 | ChessRules.VALUES |
| 84 | ); |
| 85 | } |
| 86 | |
| 87 | static GenRandInitFen() { |
| 88 | let pieces = { w: new Array(10), b: new Array(10) }; |
| 89 | for (let c of ["w", "b"]) { |
| 90 | let positions = ArrayFun.range(8); |
| 91 | |
| 92 | // Get random squares for grasshoppers (unconstrained) |
| 93 | let randIndex = randInt(8); |
| 94 | const grasshopper1Pos = positions[randIndex]; |
| 95 | positions.splice(randIndex, 1); |
| 96 | randIndex = randInt(7); |
| 97 | const grasshopper2Pos = positions[randIndex]; |
| 98 | positions.splice(randIndex, 1); |
| 99 | |
| 100 | // Knights |
| 101 | randIndex = randInt(6); |
| 102 | let knight1Pos = positions[randIndex]; |
| 103 | positions.splice(randIndex, 1); |
| 104 | randIndex = randInt(5); |
| 105 | let knight2Pos = positions[randIndex]; |
| 106 | positions.splice(randIndex, 1); |
| 107 | |
| 108 | // Queen |
| 109 | randIndex = randInt(4); |
| 110 | let queenPos = positions[randIndex]; |
| 111 | positions.splice(randIndex, 1); |
| 112 | |
| 113 | let rook1Pos = positions[0]; |
| 114 | let kingPos = positions[1]; |
| 115 | let rook2Pos = positions[2]; |
| 116 | |
| 117 | pieces[c][rook1Pos] = "r"; |
| 118 | pieces[c][knight1Pos] = "n"; |
| 119 | pieces[c][grasshopper1Pos] = "g"; |
| 120 | pieces[c][queenPos] = "q"; |
| 121 | pieces[c][kingPos] = "k"; |
| 122 | pieces[c][grasshopper2Pos] = "g"; |
| 123 | pieces[c][knight2Pos] = "n"; |
| 124 | pieces[c][rook2Pos] = "r"; |
| 125 | } |
| 126 | return ( |
| 127 | pieces["b"].join("") + |
| 128 | "/pppppppp/8/8/8/8/PPPPPPPP/" + |
| 129 | pieces["w"].join("").toUpperCase() + |
| 130 | " w 0 1111 -" |
| 131 | ); |
| 132 | } |
| 133 | }; |