de7221689b0f2fd52baeaf01092d72ac3dce0795
[vchess.git] / client / src / variants / Upsidedown.js
1 import { ChessRules } from "@/base_rules";
2 import { randInt } from "@/utils/alea";
3 import { ArrayFun } from "@/utils/array";
4
5 export const VariantRules = class UpsidedownRules extends ChessRules
6 {
7 static get HasFlags() { return false; }
8
9 static get HasEnpassant() { return false; }
10
11 getPotentialKingMoves(sq)
12 {
13 // No castle
14 return this.getSlideNJumpMoves(sq,
15 V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
16 }
17
18 static GenRandInitFen()
19 {
20 let pieces = { "w": new Array(8), "b": new Array(8) };
21 for (let c of ["w","b"])
22 {
23 let positions = ArrayFun.range(8);
24
25 let randIndex = randInt(8);
26 const kingPos = positions[randIndex];
27 positions.splice(randIndex, 1);
28
29 // At least a knight must be next to the king:
30 let knight1Pos = undefined;
31 if (kingPos == 0)
32 knight1Pos = 1;
33 else if (kingPos == V.size.y-1)
34 knight1Pos = V.size.y-2;
35 else
36 knight1Pos = kingPos + (Math.random() < 0.5 ? 1 : -1);
37 // Search for knight1Pos index in positions and remove it
38 const knight1Index = positions.indexOf(knight1Pos);
39 positions.splice(knight1Index, 1);
40
41 // King+knight1 are on two consecutive squares: one light, one dark
42 randIndex = 2 * randInt(3);
43 const bishop1Pos = positions[randIndex];
44 let randIndex_tmp = 2 * randInt(3) + 1;
45 const bishop2Pos = positions[randIndex_tmp];
46 positions.splice(Math.max(randIndex,randIndex_tmp), 1);
47 positions.splice(Math.min(randIndex,randIndex_tmp), 1);
48
49 randIndex = randInt(4);
50 const knight2Pos = positions[randIndex];
51 positions.splice(randIndex, 1);
52
53 randIndex = randInt(3);
54 const queenPos = positions[randIndex];
55 positions.splice(randIndex, 1);
56
57 const rook1Pos = positions[0];
58 const rook2Pos = positions[1];
59
60 pieces[c][rook1Pos] = 'r';
61 pieces[c][knight1Pos] = 'n';
62 pieces[c][bishop1Pos] = 'b';
63 pieces[c][queenPos] = 'q';
64 pieces[c][kingPos] = 'k';
65 pieces[c][bishop2Pos] = 'b';
66 pieces[c][knight2Pos] = 'n';
67 pieces[c][rook2Pos] = 'r';
68 }
69 return pieces["w"].join("").toUpperCase() +
70 "/PPPPPPPP/8/8/8/8/pppppppp/" +
71 pieces["b"].join("") +
72 " w 0"; //no castle, no en-passant
73 }
74 }