Fixes + implement Cylinder Chess
[vchess.git] / client / src / variants / Checkered.js
1 import { ChessRules } from "@/base_rules";
2
3 export const VariantRules = class CheckeredRules extends ChessRules {
4 static board2fen(b) {
5 const checkered_codes = {
6 p: "s",
7 q: "t",
8 r: "u",
9 b: "c",
10 n: "o"
11 };
12 if (b[0] == "c") return checkered_codes[b[1]];
13 return ChessRules.board2fen(b);
14 }
15
16 static fen2board(f) {
17 // Tolerate upper-case versions of checkered pieces (why not?)
18 const checkered_pieces = {
19 s: "p",
20 S: "p",
21 t: "q",
22 T: "q",
23 u: "r",
24 U: "r",
25 c: "b",
26 C: "b",
27 o: "n",
28 O: "n"
29 };
30 if (Object.keys(checkered_pieces).includes(f))
31 return "c" + checkered_pieces[f];
32 return ChessRules.fen2board(f);
33 }
34
35 static get PIECES() {
36 return ChessRules.PIECES.concat(["s", "t", "u", "c", "o"]);
37 }
38
39 getPpath(b) {
40 return b[0] == "c" ? "Checkered/" + b : b;
41 }
42
43 setOtherVariables(fen) {
44 super.setOtherVariables(fen);
45 // Local stack of non-capturing checkered moves:
46 this.cmoves = [];
47 const cmove = fen.split(" ")[5];
48 if (cmove == "-") this.cmoves.push(null);
49 else {
50 this.cmoves.push({
51 start: ChessRules.SquareToCoords(cmove.substr(0, 2)),
52 end: ChessRules.SquareToCoords(cmove.substr(2))
53 });
54 }
55 }
56
57 static IsGoodFen(fen) {
58 if (!ChessRules.IsGoodFen(fen)) return false;
59 const fenParts = fen.split(" ");
60 if (fenParts.length != 6) return false;
61 if (fenParts[5] != "-" && !fenParts[5].match(/^([a-h][1-8]){2}$/))
62 return false;
63 return true;
64 }
65
66 static IsGoodFlags(flags) {
67 // 4 for castle + 16 for pawns
68 return !!flags.match(/^[01]{20,20}$/);
69 }
70
71 setFlags(fenflags) {
72 super.setFlags(fenflags); //castleFlags
73 this.pawnFlags = {
74 w: [...Array(8).fill(true)], //pawns can move 2 squares?
75 b: [...Array(8).fill(true)]
76 };
77 const flags = fenflags.substr(4); //skip first 4 digits, for castle
78 for (let c of ["w", "b"]) {
79 for (let i = 0; i < 8; i++)
80 this.pawnFlags[c][i] = flags.charAt((c == "w" ? 0 : 8) + i) == "1";
81 }
82 }
83
84 aggregateFlags() {
85 return [this.castleFlags, this.pawnFlags];
86 }
87
88 disaggregateFlags(flags) {
89 this.castleFlags = flags[0];
90 this.pawnFlags = flags[1];
91 }
92
93 getCmove(move) {
94 if (move.appear[0].c == "c" && move.vanish.length == 1)
95 return { start: move.start, end: move.end };
96 return null;
97 }
98
99 canTake([x1, y1], [x2, y2]) {
100 const color1 = this.getColor(x1, y1);
101 const color2 = this.getColor(x2, y2);
102 // Checkered aren't captured
103 return (
104 color1 != color2 &&
105 color2 != "c" &&
106 (color1 != "c" || color2 != this.turn)
107 );
108 }
109
110 // Post-processing: apply "checkerization" of standard moves
111 getPotentialMovesFrom([x, y]) {
112 let standardMoves = super.getPotentialMovesFrom([x, y]);
113 const lastRank = this.turn == "w" ? 0 : 7;
114 // King has to be treated differently (for castles)
115 if (this.getPiece(x, y) == V.KING) return standardMoves;
116 let moves = [];
117 standardMoves.forEach(m => {
118 if (m.vanish[0].p == V.PAWN) {
119 if (
120 Math.abs(m.end.x - m.start.x) == 2 &&
121 !this.pawnFlags[this.turn][m.start.y]
122 )
123 return; //skip forbidden 2-squares jumps
124 if (
125 this.board[m.end.x][m.end.y] == V.EMPTY &&
126 m.vanish.length == 2 &&
127 this.getColor(m.start.x, m.start.y) == "c"
128 ) {
129 return; //checkered pawns cannot take en-passant
130 }
131 }
132 if (m.vanish.length == 1) moves.push(m);
133 // No capture
134 else {
135 // A capture occured (m.vanish.length == 2)
136 m.appear[0].c = "c";
137 moves.push(m);
138 if (
139 m.appear[0].p != m.vanish[1].p && //avoid promotions (already treated):
140 (m.vanish[0].p != V.PAWN || m.end.x != lastRank)
141 ) {
142 // Add transformation into captured piece
143 let m2 = JSON.parse(JSON.stringify(m));
144 m2.appear[0].p = m.vanish[1].p;
145 moves.push(m2);
146 }
147 }
148 });
149 return moves;
150 }
151
152 canIplay(side, [x, y]) {
153 return side == this.turn && [side, "c"].includes(this.getColor(x, y));
154 }
155
156 // Does m2 un-do m1 ? (to disallow undoing checkered moves)
157 oppositeMoves(m1, m2) {
158 return (
159 m1 &&
160 m2.appear[0].c == "c" &&
161 m2.appear.length == 1 &&
162 m2.vanish.length == 1 &&
163 m1.start.x == m2.end.x &&
164 m1.end.x == m2.start.x &&
165 m1.start.y == m2.end.y &&
166 m1.end.y == m2.start.y
167 );
168 }
169
170 filterValid(moves) {
171 if (moves.length == 0) return [];
172 const color = this.turn;
173 const L = this.cmoves.length; //at least 1: init from FEN
174 return moves.filter(m => {
175 if (this.oppositeMoves(this.cmoves[L - 1], m)) return false;
176 this.play(m);
177 const res = !this.underCheck(color);
178 this.undo(m);
179 return res;
180 });
181 }
182
183 isAttackedByPawn([x, y], colors) {
184 for (let c of colors) {
185 const color = c == "c" ? this.turn : c;
186 let pawnShift = color == "w" ? 1 : -1;
187 if (x + pawnShift >= 0 && x + pawnShift < 8) {
188 for (let i of [-1, 1]) {
189 if (
190 y + i >= 0 &&
191 y + i < 8 &&
192 this.getPiece(x + pawnShift, y + i) == V.PAWN &&
193 this.getColor(x + pawnShift, y + i) == c
194 ) {
195 return true;
196 }
197 }
198 }
199 }
200 return false;
201 }
202
203 underCheck(color) {
204 return this.isAttacked(this.kingPos[color], [V.GetOppCol(color), "c"]);
205 }
206
207 getCheckSquares(color) {
208 // Artifically change turn, for checkered pawns
209 this.turn = V.GetOppCol(color);
210 const kingAttacked = this.isAttacked(this.kingPos[color], [
211 V.GetOppCol(color),
212 "c"
213 ]);
214 let res = kingAttacked
215 ? [JSON.parse(JSON.stringify(this.kingPos[color]))] //need to duplicate!
216 : [];
217 this.turn = color;
218 return res;
219 }
220
221 updateVariables(move) {
222 super.updateVariables(move);
223 // Does this move turn off a 2-squares pawn flag?
224 const secondRank = [1, 6];
225 if (secondRank.includes(move.start.x) && move.vanish[0].p == V.PAWN)
226 this.pawnFlags[move.start.x == 6 ? "w" : "b"][move.start.y] = false;
227 }
228
229 getCurrentScore() {
230 if (this.atLeastOneMove())
231 // game not over
232 return "*";
233
234 const color = this.turn;
235 // Artifically change turn, for checkered pawns
236 this.turn = V.GetOppCol(this.turn);
237 const res = this.isAttacked(this.kingPos[color], [V.GetOppCol(color), "c"])
238 ? color == "w"
239 ? "0-1"
240 : "1-0"
241 : "1/2";
242 this.turn = V.GetOppCol(this.turn);
243 return res;
244 }
245
246 evalPosition() {
247 let evaluation = 0;
248 //Just count material for now, considering checkered neutral (...)
249 for (let i = 0; i < V.size.x; i++) {
250 for (let j = 0; j < V.size.y; j++) {
251 if (this.board[i][j] != V.EMPTY) {
252 const sqColor = this.getColor(i, j);
253 const sign = sqColor == "w" ? 1 : sqColor == "b" ? -1 : 0;
254 evaluation += sign * V.VALUES[this.getPiece(i, j)];
255 }
256 }
257 }
258 return evaluation;
259 }
260
261 static GenRandInitFen() {
262 const randFen = ChessRules.GenRandInitFen();
263 // Add 16 pawns flags + empty cmove:
264 return randFen.replace(" w 0 1111", " w 0 11111111111111111111 -");
265 }
266
267 static ParseFen(fen) {
268 return Object.assign({}, ChessRules.ParseFen(fen), {
269 cmove: fen.split(" ")[5]
270 });
271 }
272
273 getFen() {
274 const L = this.cmoves.length;
275 const cmoveFen = !this.cmoves[L - 1]
276 ? "-"
277 : ChessRules.CoordsToSquare(this.cmoves[L - 1].start) +
278 ChessRules.CoordsToSquare(this.cmoves[L - 1].end);
279 return super.getFen() + " " + cmoveFen;
280 }
281
282 getFlagsFen() {
283 let fen = super.getFlagsFen();
284 // Add pawns flags
285 for (let c of ["w", "b"]) {
286 for (let i = 0; i < 8; i++) fen += this.pawnFlags[c][i] ? "1" : "0";
287 }
288 return fen;
289 }
290
291 // TODO (design): this cmove update here or in (un)updateVariables ?
292 play(move) {
293 this.cmoves.push(this.getCmove(move));
294 super.play(move);
295 }
296
297 undo(move) {
298 this.cmoves.pop();
299 super.undo(move);
300 }
301
302 getNotation(move) {
303 if (move.appear.length == 2) {
304 // Castle
305 if (move.end.y < move.start.y) return "0-0-0";
306 return "0-0";
307 }
308
309 // Translate final square
310 const finalSquare = V.CoordsToSquare(move.end);
311
312 const piece = this.getPiece(move.start.x, move.start.y);
313 if (piece == V.PAWN) {
314 // Pawn move
315 let notation = "";
316 if (move.vanish.length > 1) {
317 // Capture
318 const startColumn = V.CoordToColumn(move.start.y);
319 notation =
320 startColumn +
321 "x" +
322 finalSquare +
323 "=" +
324 move.appear[0].p.toUpperCase();
325 } //no capture
326 else {
327 notation = finalSquare;
328 if (move.appear.length > 0 && piece != move.appear[0].p)
329 //promotion
330 notation += "=" + move.appear[0].p.toUpperCase();
331 }
332 return notation;
333 }
334 // Piece movement
335 return (
336 piece.toUpperCase() +
337 (move.vanish.length > 1 ? "x" : "") +
338 finalSquare +
339 (move.vanish.length > 1 ? "=" + move.appear[0].p.toUpperCase() : "")
340 );
341 }
342 };