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1 | import { ChessRules } from "@/base_rules"; |
2 | import { ArrayFun } from "@/utils/array"; | |
3 | import { randInt } from "@/utils/alea"; | |
4 | ||
32f6285e | 5 | export class GrasshopperRules extends ChessRules { |
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6 | static get HasEnpassant() { |
7 | return false; | |
8 | } | |
9 | ||
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10 | static get PawnSpecs() { |
11 | return Object.assign( | |
12 | {}, | |
13 | ChessRules.PawnSpecs, | |
1c15969e | 14 | { promotions: ChessRules.PawnSpecs.promotions.concat([V.GRASSHOPPER]) } |
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15 | ); |
16 | } | |
17 | ||
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18 | static get GRASSHOPPER() { |
19 | return "g"; | |
20 | } | |
21 | ||
22 | static get PIECES() { | |
23 | return ChessRules.PIECES.concat([V.GRASSHOPPER]); | |
24 | } | |
25 | ||
26 | getPpath(b) { | |
27 | return (b[1] == V.GRASSHOPPER ? "Grasshopper/" : "") + b; | |
28 | } | |
29 | ||
30 | getPotentialMovesFrom([x, y]) { | |
31 | switch (this.getPiece(x, y)) { | |
32 | case V.GRASSHOPPER: | |
33 | return this.getPotentialGrasshopperMoves([x, y]); | |
34 | default: | |
35 | return super.getPotentialMovesFrom([x, y]); | |
36 | } | |
37 | } | |
38 | ||
39 | getPotentialGrasshopperMoves([x, y]) { | |
40 | let moves = []; | |
41 | // Look in every direction until an obstacle (to jump) is met | |
42 | for (const step of V.steps[V.ROOK].concat(V.steps[V.BISHOP])) { | |
43 | let i = x + step[0]; | |
44 | let j = y + step[1]; | |
45 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
46 | i += step[0]; | |
47 | j += step[1]; | |
48 | } | |
49 | // Move is valid if the next square is empty or occupied by enemy | |
50 | const nextSq = [i+step[0], j+step[1]]; | |
51 | if (V.OnBoard(nextSq[0], nextSq[1]) && this.canTake([x, y], nextSq)) | |
52 | moves.push(this.getBasicMove([x, y], nextSq)); | |
53 | } | |
54 | return moves; | |
55 | } | |
56 | ||
68e19a44 | 57 | isAttacked(sq, color) { |
a97bdbda | 58 | return ( |
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59 | super.isAttacked(sq, color) || |
60 | this.isAttackedByGrasshopper(sq, color) | |
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61 | ); |
62 | } | |
63 | ||
68e19a44 | 64 | isAttackedByGrasshopper([x, y], color) { |
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65 | // Reversed process: is there an adjacent obstacle, |
66 | // and a grasshopper next in the same line? | |
67 | for (const step of V.steps[V.ROOK].concat(V.steps[V.BISHOP])) { | |
68 | const nextSq = [x+step[0], y+step[1]]; | |
69 | if ( | |
70 | V.OnBoard(nextSq[0], nextSq[1]) && | |
71 | this.board[nextSq[0]][nextSq[1]] != V.EMPTY | |
72 | ) { | |
73 | let i = nextSq[0] + step[0]; | |
74 | let j = nextSq[1] + step[1]; | |
75 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
76 | i += step[0]; | |
77 | j += step[1]; | |
78 | } | |
79 | if ( | |
80 | V.OnBoard(i, j) && | |
81 | this.getPiece(i, j) == V.GRASSHOPPER && | |
68e19a44 | 82 | this.getColor(i, j) == color |
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83 | ) { |
84 | return true; | |
85 | } | |
86 | } | |
87 | } | |
88 | return false; | |
89 | } | |
90 | ||
91 | static get VALUES() { | |
92 | return Object.assign( | |
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93 | // TODO: grasshoppers power decline with less pieces on board... |
94 | { g: 2 }, | |
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95 | ChessRules.VALUES |
96 | ); | |
97 | } | |
98 | ||
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99 | static get SEARCH_DEPTH() { |
100 | return 2; | |
101 | } | |
102 | ||
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103 | static GenRandInitFen(randomness) { |
104 | return ChessRules.GenRandInitFen(randomness) | |
3a2a7b5f | 105 | .slice(0, -2) |
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106 | .replace( |
107 | "/pppppppp/8/8/8/8/PPPPPPPP/", | |
108 | "/gggggggg/pppppppp/8/8/PPPPPPPP/GGGGGGGG/" | |
109 | ); | |
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110 | } |
111 | }; |