client/src/variants/Fusion.js

   1 import { ChessRules, Move, PiPo } from "@/base_rules";
   2
   3 export class FusionRules extends ChessRules {
   4
   5   static get PawnSpecs() {
   6     return (
   7       Object.assign(
   8         { promotions: [V.ROOK, V.KNIGHT, V.BISHOP] },
   9         ChessRules.PawnSpecs
  10       )
  11     );
  12   }
  13
  14   static IsGoodPosition(position) {
  15     if (position.length == 0) return false;
  16     const rows = position.split("/");
  17     if (rows.length != V.size.x) return false;
  18     let kings = { "k": 0, "K": 0 };
  19     for (let row of rows) {
  20       let sumElts = 0;
  21       for (let i = 0; i < row.length; i++) {
  22         if (['K', 'F', 'G', 'C'].includes(row[i])) kings['K']++;
  23         else if (['k', 'f', 'g', 'c'].includes(row[i])) kings['k']++;
  24         if (V.PIECES.includes(row[i].toLowerCase())) sumElts++;
  25         else {
  26           const num = parseInt(row[i], 10);
  27           if (isNaN(num) || num <= 0) return false;
  28           sumElts += num;
  29         }
  30       }
  31       if (sumElts != V.size.y) return false;
  32     }
  33     if (Object.values(kings).some(v => v != 1)) return false;
  34     return true;
  35   }
  36
  37   scanKings(fen) {
  38     this.kingPos = { w: [-1, -1], b: [-1, -1] };
  39     const fenRows = V.ParseFen(fen).position.split("/");
  40     for (let i = 0; i < fenRows.length; i++) {
  41       let k = 0;
  42       for (let j = 0; j < fenRows[i].length; j++) {
  43         const ch_ij = fenRows[i].charAt(j);
  44         if (['k', 'f', 'g', 'c'].includes(ch_ij))
  45           this.kingPos["b"] = [i, k];
  46         else if (['K', 'F', 'G', 'C'].includes(ch_ij))
  47           this.kingPos["w"] = [i, k];
  48         else {
  49           const num = parseInt(fenRows[i].charAt(j), 10);
  50           if (!isNaN(num)) k += num - 1;
  51         }
  52         k++;
  53       }
  54     }
  55   }
  56
  57   canTake([x1, y1], [x2, y2]) {
  58     if (this.getColor(x1, y1) !== this.getColor(x2, y2)) return true;
  59     const p1 = this.getPiece(x1, y1);
  60     const p2 = this.getPiece(x2, y2);
  61     return (
  62       p1 != p2 &&
  63       [V.ROOK, V.KNIGHT, V.BISHOP].includes(p1) &&
  64       [V.KING, V.ROOK, V.KNIGHT, V.BISHOP].includes(p2)
  65     );
  66   }
  67
  68   getPpath(b) {
  69     if ([V.BN, V.RN, V.KB, V.KR, V.KN].includes(b[1])) return "Fusion/" + b;
  70     return b;
  71   }
  72
  73   // Three new pieces: rook+knight, bishop+knight and queen+knight
  74   static get RN() {
  75     // Marshall
  76     return 'm';
  77   }
  78   static get BN() {
  79     // Paladin
  80     return 'd';
  81   }
  82   static get KB() {
  83     // Pontiff
  84     return 'f';
  85   }
  86   static get KR() {
  87     // Dragon King
  88     return 'g';
  89   }
  90   static get KN() {
  91     // Cavalier King
  92     return 'c';
  93   }
  94
  95   static get PIECES() {
  96     return ChessRules.PIECES.concat([V.RN, V.BN, V.KB, V.KR, V.KN]);
  97   }
  98
  99   static Fusion(p1, p2) {
 100     if (p2 == V.KING) {
 101       switch (p1) {
 102         case V.ROOK: return V.KR;
 103         case V.BISHOP: return V.KB;
 104         case V.KNIGHT: return V.KN;
 105       }
 106     }
 107     if ([p1, p2].includes(V.KNIGHT)) {
 108       if ([p1, p2].includes(V.ROOK)) return V.RN;
 109       return V.BN;
 110     }
 111     // Only remaining combination is rook + bishop = queen
 112     return V.QUEEN;
 113   }
 114
 115   getPotentialMovesFrom(sq) {
 116     let moves = [];
 117     const piece = this.getPiece(sq[0], sq[1]);
 118     switch (piece) {
 119       case V.RN:
 120         moves =
 121           super.getPotentialRookMoves(sq).concat(
 122           super.getPotentialKnightMoves(sq)).concat(
 123           this.getFissionMoves(sq));
 124         break;
 125       case V.BN:
 126         moves =
 127           super.getPotentialBishopMoves(sq).concat(
 128           super.getPotentialKnightMoves(sq)).concat(
 129           this.getFissionMoves(sq));
 130         break;
 131       case V.KN:
 132         moves =
 133           super.getPotentialKingMoves(sq).concat(
 134           this.getPotentialKingAsKnightMoves(sq)).concat(
 135           this.getFissionMoves(sq));
 136         break;
 137       case V.KB:
 138         moves =
 139           super.getPotentialKingMoves(sq).concat(
 140           this.getPotentialKingAsBishopMoves(sq)).concat(
 141           this.getFissionMoves(sq));
 142         break;
 143       case V.KR:
 144         moves =
 145           super.getPotentialKingMoves(sq).concat(
 146           this.getPotentialKingAsRookMoves(sq)).concat(
 147           this.getFissionMoves(sq));
 148         break;
 149       case V.QUEEN:
 150         moves =
 151           super.getPotentialQueenMoves(sq).concat(this.getFissionMoves(sq));
 152         break;
 153       default:
 154         moves = super.getPotentialMovesFrom(sq);
 155         break;
 156     }
 157     moves.forEach(m => {
 158       if (
 159         m.vanish.length == 2 &&
 160         m.appear.length == 1 &&
 161         m.vanish[0].c == m.vanish[1].c
 162       ) {
 163         // Augment pieces abilities in case of self-captures
 164         m.appear[0].p = V.Fusion(piece, m.vanish[1].p);
 165       }
 166     });
 167     return moves;
 168   }
 169
 170   getSlideNJumpMoves_fission([x, y], moving, staying, steps, oneStep) {
 171     let moves = [];
 172     const c = this.getColor(x, y);
 173     outerLoop: for (let step of steps) {
 174       let i = x + step[0];
 175       let j = y + step[1];
 176       while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
 177         moves.push(
 178           new Move({
 179             appear: [
 180               new PiPo({ x: i, y: j, c: c, p: moving }),
 181               new PiPo({ x: x, y: y, c: c, p: staying }),
 182             ],
 183             vanish: [
 184               new PiPo({ x: x, y: y, c: c, p: this.getPiece(x, y) })
 185             ]
 186           })
 187         );
 188         if (oneStep) continue outerLoop;
 189         i += step[0];
 190         j += step[1];
 191       }
 192     }
 193     return moves;
 194   }
 195
 196   getFissionMoves(sq) {
 197     // Square attacked by opponent?
 198     const color = this.getColor(sq[0], sq[1]);
 199     const oppCol = V.GetOppCol(color);
 200     if (this.isAttacked(sq, oppCol)) return [];
 201     // Ok, fission a priori valid
 202     const kSteps = V.steps[V.BISHOP].concat(V.steps[V.BISHOP]);
 203     switch (this.getPiece(sq[0], sq[1])) {
 204       case V.BN:
 205         return (
 206           this.getSlideNJumpMoves_fission(
 207             sq, V.BISHOP, V.KNIGHT, V.steps[V.BISHOP])
 208           .concat(this.getSlideNJumpMoves_fission(
 209             sq, V.KNIGHT, V.BISHOP, V.steps[V.KNIGHT], "oneStep"))
 210         );
 211       case V.RN:
 212         return (
 213           this.getSlideNJumpMoves_fission(
 214             sq, V.ROOK, V.KNIGHT, V.steps[V.ROOK])
 215           .concat(this.getSlideNJumpMoves_fission(
 216             sq, V.KNIGHT, V.ROOK, V.steps[V.KNIGHT], "oneStep"))
 217         );
 218       case V.KN:
 219         return (
 220           this.getSlideNJumpMoves_fission(sq, V.KING, V.KNIGHT, kSteps)
 221           .concat(this.getSlideNJumpMoves_fission(
 222             sq, V.KNIGHT, V.KING, V.steps[V.KNIGHT], "oneStep"))
 223         );
 224       case V.KB:
 225         return (
 226           this.getSlideNJumpMoves_fission(sq, V.KING, V.BISHOP, kSteps)
 227           .concat(this.getSlideNJumpMoves_fission(
 228             sq, V.BISHOP, V.KING, V.steps[V.BISHOP]))
 229         );
 230       case V.KR:
 231         return (
 232           this.getSlideNJumpMoves_fission(sq, V.KING, V.ROOK, kSteps)
 233           .concat(this.getSlideNJumpMoves_fission(
 234             sq, V.ROOK, V.KING, V.steps[V.ROOK]))
 235         );
 236       case V.QUEEN:
 237         return (
 238           this.getSlideNJumpMoves_fission(
 239             sq, V.BISHOP, V.ROOK, V.steps[V.BISHOP])
 240           .concat(this.getSlideNJumpMoves_fission(
 241             sq, V.ROOK, V.BISHOP, V.steps[V.ROOK]))
 242         );
 243     }
 244   }
 245
 246   intermediateSquaresFromKnightStep(step) {
 247     if (step[0] == 2) return [ [1, 0], [1, step[1]] ];
 248     if (step[0] == -2) return [ [-1, 0], [-1, step[1]] ];
 249     if (step[1] == 2) return [ [0, 1], [step[1], 1] ];
 250     // step[1] == -2:
 251     return [ [0, -1], [step[1], -1] ];
 252   }
 253
 254   getPotentialKingAsKnightMoves([x, y]) {
 255     const oppCol = V.GetOppCol(this.turn);
 256     let moves = [];
 257     let intermediateOk = {};
 258     for (let s of V.steps[V.KNIGHT]) {
 259       const [i, j] = [x + s[0], y + s[1]];
 260       if (!V.OnBoard(i, j) || this.board[i][j] != V.EMPTY) continue;
 261       const iSq = this.intermediateSquaresFromKnightStep(s);
 262       let moveOk = false;
 263       for (let sq of iSq) {
 264         const key = sq[0] + "_" + sq[1];
 265         if (Object.keys(intermediateOk).includes(key)) {
 266           if (intermediateOk[key]) moveOk = true;
 267         }
 268         else {
 269           moveOk = !this.isAttacked([x + sq[0], y + sq[1]], oppCol);
 270           intermediateOk[key] = moveOk;
 271         }
 272         if (moveOk) break;
 273       }
 274       if (moveOk) moves.push(this.getBasicMove([x, y], [i, j]));
 275     }
 276     return moves;
 277   }
 278
 279   getPotentialKingMovesAsSlider([x, y], slider) {
 280     const oppCol = V.GetOppCol(this.turn);
 281     let moves = [];
 282     for (let s of V.steps[slider]) {
 283       let [i, j] = [x + s[0], y + s[1]];
 284       if (
 285         !V.OnBoard(i, j) ||
 286         this.board[i][j] != V.EMPTY ||
 287         this.isAttacked([i, j], oppCol)
 288       ) {
 289         continue;
 290       }
 291       i += s[0];
 292       j += s[1];
 293       while (
 294         V.OnBoard(i, j) &&
 295         this.board[i][j] == V.EMPTY &&
 296         // TODO: this test will be done twice (also in filterValid())
 297         !this.isAttacked([i, j], oppCol)
 298       ) {
 299         moves.push(this.getBasicMove([x, y], [i, j]));
 300         i += s[0];
 301         j += s[1];
 302       }
 303     }
 304     return moves;
 305   }
 306
 307   getPotentialKingAsBishopMoves(sq) {
 308     return this.getPotentialKingMovesAsSlider(sq, V.BISHOP);
 309   }
 310
 311   getPotentialKingAsRookMoves(sq) {
 312     return this.getPotentialKingMovesAsSlider(sq, V.ROOK);
 313   }
 314
 315   isAttacked(sq, color) {
 316     return (
 317       super.isAttacked(sq, color) ||
 318       this.isAttackedByBN(sq, color) ||
 319       this.isAttackedByRN(sq, color) ||
 320       this.isAttackedByKN(sq, color) ||
 321       this.isAttackedByKB(sq, color) ||
 322       this.isAttackedByKR(sq, color)
 323     );
 324   }
 325
 326   isAttackedByBN(sq, color) {
 327     return (
 328       this.isAttackedBySlideNJump(sq, color, V.BN, V.steps[V.BISHOP]) ||
 329       this.isAttackedBySlideNJump(sq, color, V.BN, V.steps[V.KNIGHT], 1)
 330     );
 331   }
 332
 333   isAttackedByRN(sq, color) {
 334     return (
 335       this.isAttackedBySlideNJump(sq, color, V.RN, V.steps[V.ROOK]) ||
 336       this.isAttackedBySlideNJump(sq, color, V.RN, V.steps[V.KNIGHT], 1)
 337     );
 338   }
 339
 340   isAttackedByKN(sq, color) {
 341     const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
 342     return (
 343       this.isAttackedBySlideNJump(sq, color, V.KN, steps, 1) ||
 344       this.isAttackedBySlideNJump(sq, color, V.KN, V.steps[V.KNIGHT], 1)
 345     );
 346   }
 347
 348   isAttackedByKB(sq, color) {
 349     const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
 350     return (
 351       this.isAttackedBySlideNJump(sq, color, V.KB, steps, 1) ||
 352       this.isAttackedBySlideNJump(sq, color, V.KB, V.steps[V.BISHOP])
 353     );
 354   }
 355
 356   isAttackedByKR(sq, color) {
 357     const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
 358     return (
 359       this.isAttackedBySlideNJump(sq, color, V.KR, steps, 1) ||
 360       this.isAttackedBySlideNJump(sq, color, V.KR, V.steps[V.ROOK])
 361     );
 362   }
 363
 364   updateCastleFlags(move, piece) {
 365     const c = V.GetOppCol(this.turn);
 366     const firstRank = (c == "w" ? V.size.x - 1 : 0);
 367     const oppCol = this.turn;
 368     const oppFirstRank = V.size.x - 1 - firstRank;
 369     if (piece == V.KING)
 370       this.castleFlags[c] = [V.size.y, V.size.y];
 371     else if (
 372       move.start.x == firstRank && //our rook moves?
 373       this.castleFlags[c].includes(move.start.y)
 374     ) {
 375       const flagIdx = (move.start.y == this.castleFlags[c][0] ? 0 : 1);
 376       this.castleFlags[c][flagIdx] = V.size.y;
 377     }
 378     // Check move endpoint: if my king or any rook position, flags off
 379     if (move.end.x == this.kingPos[c][0] && move.end.y == this.kingPos[c][1])
 380       this.castleFlags[c] = [V.size.y, V.size.y];
 381     else if (
 382       move.end.x == firstRank &&
 383       this.castleFlags[c].includes(move.end.y)
 384     ) {
 385       const flagIdx = (move.end.y == this.castleFlags[c][0] ? 0 : 1);
 386       this.castleFlags[c][flagIdx] = V.size.y;
 387     }
 388     else if (
 389       move.end.x == oppFirstRank &&
 390       this.castleFlags[oppCol].includes(move.end.y)
 391     ) {
 392       const flagIdx = (move.end.y == this.castleFlags[oppCol][0] ? 0 : 1);
 393       this.castleFlags[oppCol][flagIdx] = V.size.y;
 394     }
 395   }
 396
 397   postPlay(move) {
 398     const c = V.GetOppCol(this.turn);
 399     move.kingMove = (
 400       [V.KING, V.KN, V.KB, V.KR].includes(move.appear[0].p) &&
 401       [V.KING, V.KN, V.KB, V.KR].includes(move.vanish[0].p)
 402     );
 403     if (move.kingMove) this.kingPos[c] = [move.appear[0].x, move.appear[0].y];
 404     this.updateCastleFlags(move, move.appear[0].p);
 405   }
 406
 407   postUndo(move) {
 408     const c = this.getColor(move.start.x, move.start.y);
 409     if (!!move.kingMove) this.kingPos[c] = [move.start.x, move.start.y];
 410   }
 411
 412   static get VALUES() {
 413     // Values such that sum of values = value of sum
 414     return Object.assign(
 415       { m: 8, d: 6, f: 1003, g: 1005, c: 1003 },
 416       ChessRules.VALUES
 417     );
 418   }
 419
 420   static get SEARCH_DEPTH() {
 421     return 2;
 422   }
 423
 424   getNotation(move) {
 425     if (move.appear.length == 2 && move.vanish.length == 1) {
 426       // Fission (because no capture in this case)
 427       return (
 428         move.appear[0].p.toUpperCase() + V.CoordsToSquare(move.end) +
 429         "/f:" + move.appear[1].p.toUpperCase() + V.CoordsToSquare(move.start)
 430       );
 431     }
 432     let notation = super.getNotation(move);
 433     if (move.vanish[0].p != V.PAWN && move.appear[0].p != move.vanish[0].p)
 434       // Fusion (not from a pawn: handled in ChessRules)
 435       notation += "=" + move.appear[0].p.toUpperCase();
 436     return notation;
 437   }
 438
 439 };