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1 | import { ChessRules } from "@/base_rules"; |
2 | ||
32f6285e | 3 | export class Knightrelay1Rules extends ChessRules { |
7e8a7ea1 | 4 | |
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5 | static get HasEnpassant() { |
6 | return false; | |
7 | } | |
8 | ||
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9 | static IsGoodPosition(position) { |
10 | if (!ChessRules.IsGoodPosition(position)) return false; | |
11 | // Check that (at least) 2 knights per side are on the board | |
12 | const rows = position.split("/"); | |
13 | let knights = { 'N': 0, 'n': 0 }; | |
14 | for (let row of rows) { | |
15 | for (let i = 0; i < row.length; i++) { | |
16 | if (['N','n'].includes(row[i])) knights[row[i]]++; | |
17 | } | |
18 | } | |
19 | if (Object.values(knights).some(v => v < 2)) return false; | |
20 | return true; | |
21 | } | |
6f2f9437 | 22 | |
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23 | getPotentialMovesFrom([x, y]) { |
24 | let moves = super.getPotentialMovesFrom([x, y]); | |
25 | ||
68e19a44 | 26 | // Expand possible moves if guarded by a knight, and is not a king: |
8055eabd | 27 | const piece = this.getPiece(x,y); |
68e19a44 | 28 | if (![V.KNIGHT,V.KING].includes(piece)) { |
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29 | const color = this.turn; |
30 | let guardedByKnight = false; | |
31 | for (const step of V.steps[V.KNIGHT]) { | |
32 | if ( | |
33 | V.OnBoard(x+step[0],y+step[1]) && | |
34 | this.getPiece(x+step[0],y+step[1]) == V.KNIGHT && | |
35 | this.getColor(x+step[0],y+step[1]) == color | |
36 | ) { | |
37 | guardedByKnight = true; | |
38 | break; | |
39 | } | |
40 | } | |
41 | if (guardedByKnight) { | |
68e19a44 | 42 | const lastRank = (color == "w" ? 0 : V.size.x - 1); |
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43 | for (const step of V.steps[V.KNIGHT]) { |
44 | if ( | |
45 | V.OnBoard(x+step[0],y+step[1]) && | |
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46 | this.getColor(x+step[0],y+step[1]) != color && |
47 | // Pawns cannot promote by knight-relay | |
48 | (piece != V.PAWN || x+step[0] != lastRank) | |
c322a844 | 49 | ) { |
68e19a44 | 50 | moves.push(this.getBasicMove([x,y], [x+step[0],y+step[1]])); |
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51 | } |
52 | } | |
53 | } | |
54 | } | |
55 | ||
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56 | // Forbid captures of knights (invincible in this variant) |
57 | return moves.filter(m => { | |
58 | return ( | |
59 | m.vanish.length == 1 || | |
60 | m.appear.length == 2 || | |
61 | m.vanish[1].p != V.KNIGHT | |
62 | ); | |
63 | }); | |
64 | } | |
65 | ||
66 | getPotentialKnightMoves(sq) { | |
67 | // Knights don't capture: | |
68 | return super.getPotentialKnightMoves(sq).filter(m => m.vanish.length == 1); | |
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69 | } |
70 | ||
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71 | isAttacked(sq, color) { |
72 | if (super.isAttacked(sq, color)) return true; | |
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73 | |
74 | // Check if a (non-knight) piece at knight distance | |
75 | // is guarded by a knight (and thus attacking) | |
9a7a1ccc | 76 | // --> Except for kings, and pawns targetting last rank. |
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77 | const x = sq[0], |
78 | y = sq[1]; | |
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79 | // Last rank for me, that is to say oppCol of color: |
80 | const lastRank = (color == 'w' ? V.size.x - 1 : 0); | |
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81 | for (const step of V.steps[V.KNIGHT]) { |
82 | if ( | |
83 | V.OnBoard(x+step[0],y+step[1]) && | |
68e19a44 | 84 | this.getColor(x+step[0],y+step[1]) == color |
1c5bfdf2 | 85 | ) { |
68e19a44 | 86 | const piece = this.getPiece(x+step[0],y+step[1]); |
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87 | if ( |
88 | ![V.KNIGHT, V.KING].includes(piece) && | |
89 | (piece != V.PAWN || x != lastRank) | |
90 | ) { | |
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91 | for (const step2 of V.steps[V.KNIGHT]) { |
92 | const xx = x+step[0]+step2[0], | |
93 | yy = y+step[1]+step2[1]; | |
94 | if ( | |
95 | V.OnBoard(xx,yy) && | |
96 | this.getColor(xx,yy) == color && | |
97 | this.getPiece(xx,yy) == V.KNIGHT | |
98 | ) { | |
99 | return true; | |
100 | } | |
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101 | } |
102 | } | |
103 | } | |
104 | } | |
105 | ||
106 | return false; | |
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107 | } |
108 | ||
109 | isAttackedByKnight(sq, color) { | |
110 | // Knights don't attack | |
111 | return false; | |
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112 | } |
113 | ||
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114 | static get VALUES() { |
115 | return { | |
116 | p: 1, | |
117 | r: 5, | |
95a66034 | 118 | n: 0, //the knight isn't captured - value doesn't matter |
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119 | b: 3, |
120 | q: 9, | |
121 | k: 1000 | |
122 | }; | |
123 | } | |
124 | ||
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125 | static get SEARCH_DEPTH() { |
126 | return 2; | |
127 | } | |
128 | ||
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129 | getNotation(move) { |
130 | if (move.appear.length == 2 && move.appear[0].p == V.KING) | |
131 | // Castle | |
132 | return move.end.y < move.start.y ? "0-0-0" : "0-0"; | |
133 | ||
134 | // Translate final and initial square | |
135 | const initSquare = V.CoordsToSquare(move.start); | |
136 | const finalSquare = V.CoordsToSquare(move.end); | |
137 | const piece = this.getPiece(move.start.x, move.start.y); | |
138 | ||
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139 | // Since pieces and pawns could move like knight, |
140 | // indicate start and end squares | |
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141 | let notation = |
142 | piece.toUpperCase() + | |
143 | initSquare + | |
144 | (move.vanish.length > move.appear.length ? "x" : "") + | |
145 | finalSquare | |
146 | ||
147 | if ( | |
148 | piece == V.PAWN && | |
149 | move.appear.length > 0 && | |
150 | move.appear[0].p != V.PAWN | |
151 | ) { | |
152 | // Promotion | |
153 | notation += "=" + move.appear[0].p.toUpperCase(); | |
154 | } | |
155 | ||
156 | return notation; | |
157 | } | |
7e8a7ea1 | 158 | |
c322a844 | 159 | }; |