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7e107b8f BA |
1 | import { ChessRules } from "@/base_rules"; |
2 | ||
3 | export class XiangqiRules extends ChessRules { | |
4 | ||
4313762d BA |
5 | static get Options() { |
6 | return null; | |
7 | } | |
8 | ||
dbc79ee6 BA |
9 | // NOTE (TODO?) scanKings() could be more efficient (in Jangqi too) |
10 | ||
7e107b8f BA |
11 | static get Monochrome() { |
12 | return true; | |
13 | } | |
14 | ||
15 | static get Notoodark() { | |
16 | return true; | |
17 | } | |
18 | ||
19 | static get Lines() { | |
20 | let lines = []; | |
21 | // Draw all inter-squares lines, shifted: | |
22 | for (let i = 0; i < V.size.x; i++) | |
23 | lines.push([[i+0.5, 0.5], [i+0.5, V.size.y-0.5]]); | |
24 | for (let j = 0; j < V.size.y; j++) | |
25 | lines.push([[0.5, j+0.5], [V.size.x-0.5, j+0.5]]); | |
26 | // Add palaces: | |
27 | lines.push([[0.5, 3.5], [2.5, 5.5]]); | |
28 | lines.push([[0.5, 5.5], [2.5, 3.5]]); | |
29 | lines.push([[9.5, 3.5], [7.5, 5.5]]); | |
30 | lines.push([[9.5, 5.5], [7.5, 3.5]]); | |
31 | // Show river: | |
32 | lines.push([[4.5, 0.5], [5.5, 8.5]]); | |
33 | lines.push([[5.5, 0.5], [4.5, 8.5]]); | |
34 | return lines; | |
35 | } | |
36 | ||
37 | static get HasFlags() { | |
38 | return false; | |
39 | } | |
40 | ||
41 | static get HasEnpassant() { | |
42 | return false; | |
43 | } | |
44 | ||
9a1e3abe BA |
45 | static get LoseOnRepetition() { |
46 | return true; | |
47 | } | |
48 | ||
7e107b8f BA |
49 | static get ELEPHANT() { |
50 | return "e"; | |
51 | } | |
52 | ||
53 | static get CANNON() { | |
54 | return "c"; | |
55 | } | |
56 | ||
57 | static get ADVISOR() { | |
58 | return "a"; | |
59 | } | |
60 | ||
61 | static get PIECES() { | |
62 | return [V.PAWN, V.ROOK, V.KNIGHT, V.ELEPHANT, V.ADVISOR, V.KING, V.CANNON]; | |
63 | } | |
64 | ||
65 | getPpath(b) { | |
66 | return "Xiangqi/" + b; | |
67 | } | |
68 | ||
69 | static get size() { | |
70 | return { x: 10, y: 9}; | |
71 | } | |
72 | ||
73 | getPotentialMovesFrom(sq) { | |
9a1e3abe BA |
74 | let moves = []; |
75 | const piece = this.getPiece(sq[0], sq[1]); | |
76 | switch (piece) { | |
77 | case V.PAWN: | |
78 | moves = this.getPotentialPawnMoves(sq); | |
79 | break; | |
80 | case V.ROOK: | |
81 | moves = super.getPotentialRookMoves(sq); | |
82 | break; | |
83 | case V.KNIGHT: | |
84 | moves = this.getPotentialKnightMoves(sq); | |
85 | break; | |
86 | case V.ELEPHANT: | |
87 | moves = this.getPotentialElephantMoves(sq); | |
88 | break; | |
89 | case V.ADVISOR: | |
90 | moves = this.getPotentialAdvisorMoves(sq); | |
91 | break; | |
92 | case V.KING: | |
93 | moves = this.getPotentialKingMoves(sq); | |
94 | break; | |
95 | case V.CANNON: | |
96 | moves = this.getPotentialCannonMoves(sq); | |
97 | break; | |
98 | } | |
99 | if (piece != V.KING && this.kingPos['w'][1] != this.kingPos['b'][1]) | |
100 | return moves; | |
101 | if (this.kingPos['w'][1] == this.kingPos['b'][1]) { | |
102 | const colKing = this.kingPos['w'][1]; | |
103 | let intercept = 0; //count intercepting pieces | |
104 | for (let i = this.kingPos['b'][0] + 1; i < this.kingPos['w'][0]; i++) { | |
105 | if (this.board[i][colKing] != V.EMPTY) intercept++; | |
106 | } | |
107 | if (intercept >= 2) return moves; | |
108 | // intercept == 1 (0 is impossible): | |
109 | // Any move not removing intercept is OK | |
110 | return moves.filter(m => { | |
111 | return ( | |
112 | // From another column? | |
113 | m.start.y != colKing || | |
114 | // From behind a king? (including kings themselves!) | |
115 | m.start.x <= this.kingPos['b'][0] || | |
116 | m.start.x >= this.kingPos['w'][0] || | |
117 | // Intercept piece moving: must remain in-between | |
118 | ( | |
119 | m.end.y == colKing && | |
120 | m.end.x > this.kingPos['b'][0] && | |
121 | m.end.x < this.kingPos['w'][0] | |
122 | ) | |
123 | ); | |
124 | }); | |
7e107b8f | 125 | } |
9a1e3abe BA |
126 | // piece == king: check only if move.end.y == enemy king column |
127 | const color = this.getColor(sq[0], sq[1]); | |
128 | const oppCol = V.GetOppCol(color); | |
129 | // colCheck == -1 if unchecked, 1 if checked and occupied, | |
130 | // 0 if checked and clear | |
131 | let colCheck = -1; | |
132 | return moves.filter(m => { | |
133 | if (m.end.y != this.kingPos[oppCol][1]) return true; | |
134 | if (colCheck < 0) { | |
135 | // Do the check: | |
136 | colCheck = 0; | |
137 | for (let i = this.kingPos['b'][0] + 1; i < this.kingPos['w'][0]; i++) { | |
138 | if (this.board[i][m.end.y] != V.EMPTY) { | |
139 | colCheck++; | |
140 | break; | |
141 | } | |
142 | } | |
143 | return colCheck == 1; | |
144 | } | |
145 | // Check already done: | |
146 | return colCheck == 1; | |
147 | }); | |
7e107b8f BA |
148 | } |
149 | ||
150 | getPotentialPawnMoves([x, y]) { | |
151 | const c = this.getColor(x, y); | |
152 | const shiftX = (c == 'w' ? -1 : 1); | |
153 | const crossedRiver = (c == 'w' && x <= 4 || c == 'b' && x >= 5); | |
154 | const lastRank = (c == 'w' && x == 0 || c == 'b' && x == 9); | |
155 | let steps = []; | |
156 | if (!lastRank) steps.push([shiftX, 0]); | |
157 | if (crossedRiver) { | |
158 | if (y > 0) steps.push([0, -1]); | |
159 | if (y < 9) steps.push([0, 1]); | |
160 | } | |
4313762d | 161 | return super.getSlideNJumpMoves([x, y], steps, 1); |
7e107b8f BA |
162 | } |
163 | ||
164 | knightStepsFromRookStep(step) { | |
165 | if (step[0] == 0) return [ [1, 2*step[1]], [-1, 2*step[1]] ]; | |
166 | return [ [2*step[0], 1], [2*step[0], -1] ]; | |
167 | } | |
168 | ||
169 | getPotentialKnightMoves([x, y]) { | |
170 | let steps = []; | |
171 | for (let rookStep of ChessRules.steps[V.ROOK]) { | |
172 | const [i, j] = [x + rookStep[0], y + rookStep[1]]; | |
173 | if (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
174 | Array.prototype.push.apply(steps, | |
175 | // These moves might be impossible, but need to be checked: | |
176 | this.knightStepsFromRookStep(rookStep)); | |
177 | } | |
178 | } | |
4313762d | 179 | return super.getSlideNJumpMoves([x, y], steps, 1); |
7e107b8f BA |
180 | } |
181 | ||
182 | getPotentialElephantMoves([x, y]) { | |
183 | let steps = []; | |
184 | const c = this.getColor(x, y); | |
185 | for (let bishopStep of ChessRules.steps[V.BISHOP]) { | |
186 | const [i, j] = [x + bishopStep[0], y + bishopStep[1]]; | |
187 | if (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
188 | const [newX, newY] = [x + 2*bishopStep[0], y + 2*bishopStep[1]]; | |
189 | if ((c == 'w' && newX >= 5) || (c == 'b' && newX <= 4)) | |
190 | // A priori valid (elephant don't cross the river) | |
191 | steps.push(bishopStep.map(s => 2*s)); | |
192 | // "out of board" checks delayed to next method | |
193 | } | |
194 | } | |
4313762d | 195 | return super.getSlideNJumpMoves([x, y], steps, 1); |
7e107b8f BA |
196 | } |
197 | ||
7e107b8f BA |
198 | getPotentialAdvisorMoves([x, y]) { |
199 | // Diagonal steps inside palace | |
7e107b8f | 200 | const c = this.getColor(x, y); |
dbc79ee6 BA |
201 | if ( |
202 | y != 4 || | |
203 | (c == 'w' && x != V.size.x - 2) || | |
204 | (c == 'b' && x != 1) | |
205 | ) { | |
206 | // In a corner: only one step available | |
207 | let step = null; | |
208 | const direction = (c == 'w' ? -1 : 1); | |
209 | if ((c == 'w' && x == V.size.x - 1) || (c == 'b' && x == 0)) { | |
210 | // On first line | |
211 | if (y == 3) step = [direction, 1]; | |
212 | else step = [direction, -1]; | |
213 | } | |
214 | else { | |
215 | // On third line | |
216 | if (y == 3) step = [-direction, 1]; | |
217 | else step = [-direction, -1]; | |
218 | } | |
4313762d | 219 | return super.getSlideNJumpMoves([x, y], [step], 1); |
7e107b8f | 220 | } |
dbc79ee6 BA |
221 | // In the middle of the palace: |
222 | return ( | |
4313762d | 223 | super.getSlideNJumpMoves([x, y], ChessRules.steps[V.BISHOP], 1) |
dbc79ee6 | 224 | ); |
7e107b8f BA |
225 | } |
226 | ||
227 | getPotentialKingMoves([x, y]) { | |
228 | // Orthogonal steps inside palace | |
7e107b8f | 229 | const c = this.getColor(x, y); |
dbc79ee6 BA |
230 | if ( |
231 | y != 4 || | |
232 | (c == 'w' && x != V.size.x - 2) || | |
233 | (c == 'b' && x != 1) | |
234 | ) { | |
235 | // On the edge: only two steps available | |
236 | let steps = []; | |
237 | if (x < (c == 'w' ? V.size.x - 1 : 2)) steps.push([1, 0]); | |
238 | if (x > (c == 'w' ? V.size.x - 3 : 0)) steps.push([-1, 0]); | |
239 | if (y > 3) steps.push([0, -1]); | |
240 | if (y < 5) steps.push([0, 1]); | |
4313762d | 241 | return super.getSlideNJumpMoves([x, y], steps, 1); |
7e107b8f | 242 | } |
dbc79ee6 BA |
243 | // In the middle of the palace: |
244 | return ( | |
4313762d | 245 | super.getSlideNJumpMoves([x, y], ChessRules.steps[V.ROOK], 1) |
dbc79ee6 | 246 | ); |
7e107b8f BA |
247 | } |
248 | ||
249 | // NOTE: duplicated from Shako (TODO?) | |
250 | getPotentialCannonMoves([x, y]) { | |
251 | const oppCol = V.GetOppCol(this.turn); | |
252 | let moves = []; | |
253 | // Look in every direction until an obstacle (to jump) is met | |
254 | for (const step of V.steps[V.ROOK]) { | |
255 | let i = x + step[0]; | |
256 | let j = y + step[1]; | |
257 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
258 | moves.push(this.getBasicMove([x, y], [i, j])); | |
259 | i += step[0]; | |
260 | j += step[1]; | |
261 | } | |
262 | // Then, search for an enemy | |
263 | i += step[0]; | |
264 | j += step[1]; | |
265 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
266 | i += step[0]; | |
267 | j += step[1]; | |
268 | } | |
269 | if (V.OnBoard(i, j) && this.getColor(i, j) == oppCol) | |
270 | moves.push(this.getBasicMove([x, y], [i, j])); | |
271 | } | |
272 | return moves; | |
273 | } | |
274 | ||
275 | // (King) Never attacked by advisor, since it stays in the palace | |
276 | // Also, never attacked by elephants since they don't cross the river. | |
277 | isAttacked(sq, color) { | |
278 | return ( | |
279 | this.isAttackedByPawn(sq, color) || | |
280 | super.isAttackedByRook(sq, color) || | |
281 | this.isAttackedByKnight(sq, color) || | |
282 | this.isAttackedByCannon(sq, color) | |
283 | ); | |
284 | } | |
285 | ||
286 | isAttackedByPawn([x, y], color) { | |
287 | // The pawn necessarily crossed the river (attack on king) | |
288 | const shiftX = (color == 'w' ? 1 : -1); //shift from king | |
1269441e | 289 | return super.isAttackedBySlideNJump( |
4313762d | 290 | [x, y], color, V.PAWN, [[shiftX, 0], [0, 1], [0, -1]], 1); |
7e107b8f BA |
291 | } |
292 | ||
293 | knightStepsFromBishopStep(step) { | |
294 | return [ [2*step[0], step[1]], [step[0], 2*step[1]] ]; | |
295 | } | |
296 | ||
297 | isAttackedByKnight([x, y], color) { | |
298 | // Check bishop steps: if empty, look continuation knight step | |
299 | let steps = []; | |
300 | for (let s of ChessRules.steps[V.BISHOP]) { | |
301 | const [i, j] = [x + s[0], y + s[1]]; | |
302 | if ( | |
303 | V.OnBoard(i, j) && | |
304 | this.board[i][j] == V.EMPTY | |
305 | ) { | |
306 | Array.prototype.push.apply(steps, this.knightStepsFromBishopStep(s)); | |
307 | } | |
308 | } | |
309 | return ( | |
4313762d | 310 | super.isAttackedBySlideNJump([x, y], color, V.KNIGHT, steps, 1) |
7e107b8f BA |
311 | ); |
312 | } | |
313 | ||
314 | // NOTE: duplicated from Shako (TODO?) | |
315 | isAttackedByCannon([x, y], color) { | |
316 | // Reversed process: is there an obstacle in line, | |
317 | // and a cannon next in the same line? | |
318 | for (const step of V.steps[V.ROOK]) { | |
319 | let [i, j] = [x+step[0], y+step[1]]; | |
320 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
321 | i += step[0]; | |
322 | j += step[1]; | |
323 | } | |
324 | if (V.OnBoard(i, j)) { | |
325 | // Keep looking in this direction | |
326 | i += step[0]; | |
327 | j += step[1]; | |
328 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
329 | i += step[0]; | |
330 | j += step[1]; | |
331 | } | |
332 | if ( | |
333 | V.OnBoard(i, j) && | |
334 | this.getPiece(i, j) == V.CANNON && | |
335 | this.getColor(i, j) == color | |
336 | ) { | |
337 | return true; | |
338 | } | |
339 | } | |
340 | } | |
341 | return false; | |
342 | } | |
343 | ||
9a1e3abe BA |
344 | getCurrentScore() { |
345 | if (this.atLeastOneMove()) return "*"; | |
346 | // Game over | |
347 | const color = this.turn; | |
348 | // No valid move: I lose! | |
349 | return (color == "w" ? "0-1" : "1-0"); | |
350 | } | |
351 | ||
7e107b8f BA |
352 | static get VALUES() { |
353 | return { | |
354 | p: 1, | |
355 | r: 9, | |
356 | n: 4, | |
357 | e: 2.5, | |
358 | a: 2, | |
359 | c: 4.5, | |
360 | k: 1000 | |
361 | }; | |
362 | } | |
363 | ||
364 | evalPosition() { | |
365 | let evaluation = 0; | |
366 | for (let i = 0; i < V.size.x; i++) { | |
367 | for (let j = 0; j < V.size.y; j++) { | |
368 | if (this.board[i][j] != V.EMPTY) { | |
369 | const c = this.getColor(i, j); | |
370 | const sign = (c == 'w' ? 1 : -1); | |
371 | const piece = this.getPiece(i, j); | |
372 | let pieceEval = V.VALUES[this.getPiece(i, j)]; | |
373 | if ( | |
374 | piece == V.PAWN && | |
375 | ( | |
376 | (c == 'w' && i <= 4) || | |
377 | (c == 'b' && i >= 5) | |
378 | ) | |
379 | ) { | |
380 | // Pawn crossed the river: higher value | |
381 | pieceEval++; | |
382 | } | |
383 | evaluation += sign * pieceEval; | |
384 | } | |
385 | } | |
386 | } | |
387 | return evaluation; | |
388 | } | |
389 | ||
1269441e BA |
390 | static get SEARCH_DEPTH() { |
391 | return 2; | |
392 | } | |
393 | ||
7e107b8f BA |
394 | static GenRandInitFen() { |
395 | // No randomization here (TODO?) | |
396 | return "rneakaenr/9/1c5c1/p1p1p1p1p/9/9/P1P1P1P1P/1C5C1/9/RNEAKAENR w 0"; | |
397 | } | |
398 | ||
dbc79ee6 BA |
399 | getNotation(move) { |
400 | let notation = super.getNotation(move); | |
401 | if (move.vanish.length == 2 && move.vanish[0].p == V.PAWN) | |
84ac89c2 | 402 | notation = "P" + notation.substr(1); |
dbc79ee6 BA |
403 | return notation; |
404 | } | |
405 | ||
7e107b8f | 406 | }; |