Add Alapo, Crossing, Kingsmaker, Squatter variants
[vchess.git] / client / src / variants / Magnetic.js
1 import { ChessRules, PiPo } from "@/base_rules";
2
3 export class MagneticRules extends ChessRules {
4
5 static get HasEnpassant() {
6 return false;
7 }
8
9 getPotentialMovesFrom([x, y]) {
10 let standardMoves = super.getPotentialMovesFrom([x, y]);
11 let moves = [];
12 standardMoves.forEach(m => {
13 let newMove_s = this.applyMagneticLaws(m);
14 if (newMove_s.length == 1) moves.push(newMove_s[0]);
15 //promotion
16 else moves = moves.concat(newMove_s);
17 });
18 return moves;
19 }
20
21 // Complete a move with magnetic actions
22 // TODO: job is done multiple times for (normal) promotions.
23 applyMagneticLaws(move) {
24 // Exception: kings are not charged
25 if (move.appear[0].p == V.KING && move.appear.length == 1) return [move];
26 // If castling, rook is charged:
27 const aIdx = move.appear[0].p != V.KING ? 0 : 1;
28 const [x, y] = [move.appear[aIdx].x, move.appear[aIdx].y];
29 const color = this.turn;
30 const lastRank = color == "w" ? 0 : 7;
31 const standardMove = JSON.parse(JSON.stringify(move));
32 this.play(standardMove);
33 for (let step of [
34 [-1, 0],
35 [1, 0],
36 [0, -1],
37 [0, 1]
38 ]) {
39 let [i, j] = [x + step[0], y + step[1]];
40 while (V.OnBoard(i, j)) {
41 if (this.board[i][j] != V.EMPTY) {
42 // Found something. Same color or not?
43 if (this.getColor(i, j) != color) {
44 // Attraction
45 if (
46 (Math.abs(i - x) >= 2 || Math.abs(j - y) >= 2) &&
47 this.getPiece(i, j) != V.KING
48 ) {
49 move.vanish.push(
50 new PiPo({
51 p: this.getPiece(i, j),
52 c: this.getColor(i, j),
53 x: i,
54 y: j
55 })
56 );
57 move.appear.push(
58 new PiPo({
59 p: this.getPiece(i, j),
60 c: this.getColor(i, j),
61 x: x + step[0],
62 y: y + step[1]
63 })
64 );
65 }
66 } else {
67 // Repulsion
68 if (this.getPiece(i, j) != V.KING) {
69 // Push it until we meet an obstacle or edge of the board
70 let [ii, jj] = [i + step[0], j + step[1]];
71 while (V.OnBoard(ii, jj)) {
72 if (this.board[ii][jj] != V.EMPTY) break;
73 ii += step[0];
74 jj += step[1];
75 }
76 ii -= step[0];
77 jj -= step[1];
78 if (Math.abs(ii - i) >= 1 || Math.abs(jj - j) >= 1) {
79 move.vanish.push(
80 new PiPo({
81 p: this.getPiece(i, j),
82 c: this.getColor(i, j),
83 x: i,
84 y: j
85 })
86 );
87 move.appear.push(
88 new PiPo({
89 p: this.getPiece(i, j),
90 c: this.getColor(i, j),
91 x: ii,
92 y: jj
93 })
94 );
95 }
96 }
97 }
98 break;
99 }
100 i += step[0];
101 j += step[1];
102 }
103 }
104 this.undo(standardMove);
105 let moves = [];
106 // Scan move for pawn (max 1) on 8th rank
107 for (let i = 1; i < move.appear.length; i++) {
108 if (
109 move.appear[i].p == V.PAWN &&
110 move.appear[i].c == color &&
111 move.appear[i].x == lastRank
112 ) {
113 move.appear[i].p = V.ROOK;
114 moves.push(move);
115 for (let piece of [V.KNIGHT, V.BISHOP, V.QUEEN]) {
116 let cmove = JSON.parse(JSON.stringify(move));
117 cmove.appear[i].p = piece;
118 moves.push(cmove);
119 }
120 // Swap appear[i] and appear[0] for moves presentation
121 // (TODO: this is awkward)
122 moves.forEach(m => {
123 let tmp = m.appear[0];
124 m.appear[0] = m.appear[i];
125 m.appear[i] = tmp;
126 });
127 break;
128 }
129 }
130 if (moves.length == 0)
131 //no pawn on 8th rank
132 moves.push(move);
133 return moves;
134 }
135
136 atLeastOneMove() {
137 if (this.kingPos[this.turn][0] < 0) return false;
138 return true; //TODO: is it right?
139 }
140
141 filterValid(moves) {
142 // There are no checks
143 return moves;
144 }
145
146 getCheckSquares() {
147 return [];
148 }
149
150 postPlay(move) {
151 super.postPlay(move);
152 const c = move.vanish[0].c;
153 if (move.vanish.length >= 2 && move.vanish[1].p == V.KING) {
154 // We took opponent king !
155 const oppCol = V.GetOppCol(c);
156 this.kingPos[oppCol] = [-1, -1];
157 this.castleFlags[oppCol] = [8, 8];
158 }
159 // Did we magnetically move our (init) rooks or opponents' ones ?
160 const firstRank = c == "w" ? 7 : 0;
161 const oppFirstRank = 7 - firstRank;
162 const oppCol = V.GetOppCol(c);
163 move.vanish.forEach(psq => {
164 if (
165 psq.x == firstRank &&
166 this.castleFlags[c].includes(psq.y)
167 ) {
168 this.castleFlags[c][psq.y == this.castleFlags[c][0] ? 0 : 1] = 8;
169 }
170 else if (
171 psq.x == oppFirstRank &&
172 this.castleFlags[oppCol].includes(psq.y)
173 ) {
174 const flagIdx = (psq.y == this.castleFlags[oppCol][0] ? 0 : 1);
175 this.castleFlags[oppCol][flagIdx] = 8;
176 }
177 });
178 }
179
180 postUndo(move) {
181 super.postUndo(move);
182 const c = move.vanish[0].c;
183 const oppCol = V.GetOppCol(c);
184 if (this.kingPos[oppCol][0] < 0) {
185 // Last move took opponent's king
186 for (let psq of move.vanish) {
187 if (psq.p == "k") {
188 this.kingPos[oppCol] = [psq.x, psq.y];
189 break;
190 }
191 }
192 }
193 }
194
195 getCurrentScore() {
196 const color = this.turn;
197 const kp = this.kingPos[color];
198 if (kp[0] < 0)
199 // King disappeared
200 return color == "w" ? "0-1" : "1-0";
201 if (this.atLeastOneMove())
202 // Game not over
203 return "*";
204 return "1/2"; //no moves but kings still there
205 }
206
207 static get THRESHOLD_MATE() {
208 return 500; //checkmates evals may be slightly below 1000
209 }
210
211 static get SEARCH_DEPTH() {
212 return 2;
213 }
214
215 };