Small fixes + early draft of Eightpieces variant
[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;
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 getAllValidMoves() {
184 const oppCol = V.GetOppCol(this.turn);
185 let potentialMoves = [];
186 for (let i = 0; i < V.size.x; i++) {
187 for (let j = 0; j < V.size.y; j++) {
188 // NOTE: just testing == color isn't enough because of checkred pieces
189 if (this.board[i][j] != V.EMPTY && this.getColor(i, j) != oppCol) {
190 Array.prototype.push.apply(
191 potentialMoves,
192 this.getPotentialMovesFrom([i, j])
193 );
194 }
195 }
196 }
197 return this.filterValid(potentialMoves);
198 }
199
200 atLeastOneMove() {
201 const oppCol = V.GetOppCol(this.turn);
202 for (let i = 0; i < V.size.x; i++) {
203 for (let j = 0; j < V.size.y; j++) {
204 // NOTE: just testing == color isn't enough because of checkred pieces
205 if (this.board[i][j] != V.EMPTY && this.getColor(i, j) != oppCol) {
206 const moves = this.getPotentialMovesFrom([i, j]);
207 if (moves.length > 0) {
208 for (let k = 0; k < moves.length; k++) {
209 if (this.filterValid([moves[k]]).length > 0) return true;
210 }
211 }
212 }
213 }
214 }
215 return false;
216 }
217
218 isAttackedByPawn([x, y], colors) {
219 for (let c of colors) {
220 const color = c == "c" ? this.turn : c;
221 let pawnShift = color == "w" ? 1 : -1;
222 if (x + pawnShift >= 0 && x + pawnShift < 8) {
223 for (let i of [-1, 1]) {
224 if (
225 y + i >= 0 &&
226 y + i < 8 &&
227 this.getPiece(x + pawnShift, y + i) == V.PAWN &&
228 this.getColor(x + pawnShift, y + i) == c
229 ) {
230 return true;
231 }
232 }
233 }
234 }
235 return false;
236 }
237
238 underCheck(color) {
239 return this.isAttacked(this.kingPos[color], [V.GetOppCol(color), "c"]);
240 }
241
242 getCheckSquares(color) {
243 // Artifically change turn, for checkered pawns
244 this.turn = V.GetOppCol(color);
245 const kingAttacked = this.isAttacked(this.kingPos[color], [
246 V.GetOppCol(color),
247 "c"
248 ]);
249 let res = kingAttacked
250 ? [JSON.parse(JSON.stringify(this.kingPos[color]))] //need to duplicate!
251 : [];
252 this.turn = color;
253 return res;
254 }
255
256 updateVariables(move) {
257 super.updateVariables(move);
258 // Does this move turn off a 2-squares pawn flag?
259 const secondRank = [1, 6];
260 if (secondRank.includes(move.start.x) && move.vanish[0].p == V.PAWN)
261 this.pawnFlags[move.start.x == 6 ? "w" : "b"][move.start.y] = false;
262 }
263
264 getCurrentScore() {
265 if (this.atLeastOneMove())
266 // game not over
267 return "*";
268
269 const color = this.turn;
270 // Artifically change turn, for checkered pawns
271 this.turn = V.GetOppCol(this.turn);
272 const res = this.isAttacked(this.kingPos[color], [V.GetOppCol(color), "c"])
273 ? color == "w"
274 ? "0-1"
275 : "1-0"
276 : "1/2";
277 this.turn = V.GetOppCol(this.turn);
278 return res;
279 }
280
281 evalPosition() {
282 let evaluation = 0;
283 // Just count material for now, considering checkered neutral (...)
284 for (let i = 0; i < V.size.x; i++) {
285 for (let j = 0; j < V.size.y; j++) {
286 if (this.board[i][j] != V.EMPTY) {
287 const sqColor = this.getColor(i, j);
288 if (["w","b"].includes(sqColor)) {
289 const sign = sqColor == "w" ? 1 : -1;
290 evaluation += sign * V.VALUES[this.getPiece(i, j)];
291 }
292 }
293 }
294 }
295 return evaluation;
296 }
297
298 static GenRandInitFen(randomness) {
299 return ChessRules.GenRandInitFen(randomness)
300 // Add 16 pawns flags + empty cmove:
301 .replace(" w 0 1111", " w 0 11111111111111111111 -");
302 }
303
304 static ParseFen(fen) {
305 return Object.assign({}, ChessRules.ParseFen(fen), {
306 cmove: fen.split(" ")[5]
307 });
308 }
309
310 getFen() {
311 const L = this.cmoves.length;
312 const cmoveFen = !this.cmoves[L - 1]
313 ? "-"
314 : ChessRules.CoordsToSquare(this.cmoves[L - 1].start) +
315 ChessRules.CoordsToSquare(this.cmoves[L - 1].end);
316 return super.getFen() + " " + cmoveFen;
317 }
318
319 getFlagsFen() {
320 let fen = super.getFlagsFen();
321 // Add pawns flags
322 for (let c of ["w", "b"]) {
323 for (let i = 0; i < 8; i++) fen += this.pawnFlags[c][i] ? "1" : "0";
324 }
325 return fen;
326 }
327
328 // TODO (design): this cmove update here or in (un)updateVariables ?
329 play(move) {
330 this.cmoves.push(this.getCmove(move));
331 super.play(move);
332 }
333
334 undo(move) {
335 this.cmoves.pop();
336 super.undo(move);
337 }
338
339 getNotation(move) {
340 if (move.appear.length == 2) {
341 // Castle
342 if (move.end.y < move.start.y) return "0-0-0";
343 return "0-0";
344 }
345
346 // Translate final square
347 const finalSquare = V.CoordsToSquare(move.end);
348
349 const piece = this.getPiece(move.start.x, move.start.y);
350 if (piece == V.PAWN) {
351 // Pawn move
352 let notation = "";
353 if (move.vanish.length > 1) {
354 // Capture
355 const startColumn = V.CoordToColumn(move.start.y);
356 notation =
357 startColumn +
358 "x" +
359 finalSquare +
360 "=" +
361 move.appear[0].p.toUpperCase();
362 } //no capture
363 else {
364 notation = finalSquare;
365 if (move.appear.length > 0 && piece != move.appear[0].p)
366 //promotion
367 notation += "=" + move.appear[0].p.toUpperCase();
368 }
369 return notation;
370 }
371 // Piece movement
372 return (
373 piece.toUpperCase() +
374 (move.vanish.length > 1 ? "x" : "") +
375 finalSquare +
376 (move.vanish.length > 1 ? "=" + move.appear[0].p.toUpperCase() : "")
377 );
378 }
379 };