client/src/variants/Spartan.js

   1 import { ChessRules } from "@/base_rules";
   2
   3 export class SpartanRules extends ChessRules {
   4
   5   static get HasEnpassant() {
   6     return false;
   7   }
   8
   9   static IsGoodFlags(flags) {
  10     // Only white can castle
  11     return !!flags.match(/^[a-z]{2,2}$/);
  12   }
  13
  14   getPpath(b) {
  15     if (b[0] == 'b' && b[1] != 'k') return "Spartan/" + b;
  16     return b;
  17   }
  18
  19   static GenRandInitFen(randomness) {
  20     if (randomness == 0)
  21       return "lgkcckwl/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w 0 ah";
  22
  23     // Mapping white --> black (first knight --> general; TODO):
  24     const piecesMap = {
  25       'r': 'c',
  26       'n': 'w',
  27       'b': 'l',
  28       'q': 'k',
  29       'k': 'k',
  30       'g': 'g'
  31     };
  32
  33     const baseFen = ChessRules.GenRandInitFen(randomness).replace('n', 'g');
  34     return (
  35       baseFen.substr(0, 8).split('').map(p => piecesMap[p]).join('') +
  36       baseFen.substr(8)
  37     );
  38   }
  39
  40   getFlagsFen() {
  41     return this.castleFlags['w'].map(V.CoordToColumn).join("");
  42   }
  43
  44   setFlags(fenflags) {
  45     this.castleFlags = { 'w': [-1, -1] };
  46     for (let i = 0; i < 2; i++)
  47       this.castleFlags['w'][i] = V.ColumnToCoord(fenflags.charAt(i));
  48   }
  49
  50   static IsGoodPosition(position) {
  51     if (position.length == 0) return false;
  52     const rows = position.split("/");
  53     if (rows.length != V.size.x) return false;
  54     let kings = { "k": 0, "K": 0 };
  55     for (let row of rows) {
  56       let sumElts = 0;
  57       for (let i = 0; i < row.length; i++) {
  58         if (['K','k'].includes(row[i])) kings[row[i]]++;
  59         if (V.PIECES.includes(row[i].toLowerCase())) sumElts++;
  60         else {
  61           const num = parseInt(row[i], 10);
  62           if (isNaN(num) || num <= 0) return false;
  63           sumElts += num;
  64         }
  65       }
  66       if (sumElts != V.size.y) return false;
  67     }
  68     // Both kings should be on board. One for white, 1 or 2 for black.
  69     if (kings['K'] != 1 || ![1, 2].includes(kings['k'])) return false;
  70     return true;
  71   }
  72
  73   scanKings(fen) {
  74     // Scan white king only:
  75     this.kingPos = { w: [-1, -1] };
  76     const fenRows = V.ParseFen(fen).position.split("/");
  77     for (let i = 0; i < fenRows.length; i++) {
  78       let k = 0;
  79       for (let j = 0; j < fenRows[i].length; j++) {
  80         switch (fenRows[i].charAt(j)) {
  81           case "K":
  82             this.kingPos["w"] = [i, k];
  83             break;
  84           default: {
  85             const num = parseInt(fenRows[i].charAt(j), 10);
  86             if (!isNaN(num)) k += num - 1;
  87           }
  88         }
  89         k++;
  90       }
  91     }
  92   }
  93
  94   static get LIEUTENANT() {
  95     return 'l';
  96   }
  97   static get GENERAL() {
  98     return 'g';
  99   }
 100   static get CAPTAIN() {
 101     return 'c';
 102   }
 103   static get WARLORD() {
 104     return 'w';
 105   }
 106
 107   static get PIECES() {
 108     return (
 109       ChessRules.PIECES.concat([V.LIEUTENANT, V.GENERAL, V.CAPTAIN, V.WARLORD])
 110     );
 111   }
 112
 113   getPotentialMovesFrom([x, y]) {
 114     if (this.getColor(x, y) == 'w') return super.getPotentialMovesFrom([x, y]);
 115     switch (this.getPiece(x, y)) {
 116       case V.PAWN: {
 117         const kings = this.getKingsPos();
 118         const moves = this.getPotentialHopliteMoves([x, y]);
 119         if (kings.length == 1) return moves;
 120         return moves.filter(m => m.appear[0].p != V.KING);
 121       }
 122       case V.KING: return this.getPotentialSpartanKingMoves([x, y]);
 123       case V.LIEUTENANT: return this.getPotentialLieutenantMoves([x, y]);
 124       case V.GENERAL: return this.getPotentialGeneralMoves([x, y]);
 125       case V.CAPTAIN: return this.getPotentialCaptainMoves([x, y]);
 126       case V.WARLORD: return this.getPotentialWarlordMoves([x, y]);
 127     }
 128     return [];
 129   }
 130
 131   static get steps() {
 132     return Object.assign(
 133       {},
 134       ChessRules.steps,
 135       {
 136         // Dabbabah
 137         'd': [
 138           [-2, 0],
 139           [0, -2],
 140           [2, 0],
 141           [0, 2]
 142         ],
 143         // Alfil
 144         'a': [
 145           [2, 2],
 146           [2, -2],
 147           [-2, 2],
 148           [-2, -2]
 149         ]
 150       }
 151     );
 152   }
 153
 154   getPotentialSpartanKingMoves(sq) {
 155     // No castle:
 156     const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
 157     return super.getSlideNJumpMoves(sq, steps, "oneStep");
 158   }
 159
 160   getPotentialHopliteMoves([x, y]) {
 161     // Berolina pawn, with initial jumping option
 162     let moves = [];
 163     if (x == 6) {
 164       const finalPieces =
 165         [V.LIEUTENANT, V.GENERAL, V.CAPTAIN, V.KING, V.WARLORD];
 166       for (let shiftY of [-1, 0, 1]) {
 167         const [i, j] = [7, y + shiftY];
 168         if (
 169           V.OnBoard(i, j) &&
 170           (
 171             (shiftY != 0 && this.board[i][j] == V.EMPTY) ||
 172             (shiftY == 0 && this.getColor(i, j) == 'w')
 173           )
 174         ) {
 175           for (let p of finalPieces)
 176             moves.push(this.getBasicMove([x, y], [i, j], { c: 'b', p: p }));
 177         }
 178       }
 179     }
 180     else {
 181       for (let shiftY of [-1, 0, 1]) {
 182         const [i, j] = [x + 1, y + shiftY];
 183         if (
 184           V.OnBoard(i, j) &&
 185           (
 186             (shiftY != 0 && this.board[i][j] == V.EMPTY) ||
 187             (shiftY == 0 && this.getColor(i, j) == 'w')
 188           )
 189         ) {
 190           moves.push(this.getBasicMove([x, y], [i, j]));
 191         }
 192       }
 193       // Add initial 2 squares jumps:
 194       if (x == 1) {
 195         for (let shiftY of [-2, 2]) {
 196           const [i, j] = [3, y + shiftY];
 197           if (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY)
 198             moves.push(this.getBasicMove([x, y], [i, j]));
 199         }
 200       }
 201     }
 202     return moves;
 203   }
 204
 205   getPotentialLieutenantMoves([x, y]) {
 206     let moves = [];
 207     for (let shiftY of [-1, 1]) {
 208       const [i, j] = [x, y + shiftY];
 209       if (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY)
 210         moves.push(this.getBasicMove([x, y], [i, j]));
 211     }
 212     const steps = V.steps[V.BISHOP].concat(V.steps['a']);
 213     Array.prototype.push.apply(
 214       moves,
 215       super.getSlideNJumpMoves([x, y], steps, "oneStep")
 216     );
 217     return moves;
 218   }
 219
 220   getPotentialCaptainMoves([x, y]) {
 221     const steps = V.steps[V.ROOK].concat(V.steps['d']);
 222     return super.getSlideNJumpMoves([x, y], steps, "oneStep")
 223   }
 224
 225   getPotentialGeneralMoves([x, y]) {
 226     return (
 227       super.getSlideNJumpMoves([x, y], V.steps[V.BISHOP], "oneStep")
 228       .concat(super.getSlideNJumpMoves([x, y], V.steps[V.ROOK]))
 229     );
 230   }
 231
 232   getPotentialWarlordMoves([x, y]) {
 233     return (
 234       super.getSlideNJumpMoves([x, y], V.steps[V.KNIGHT], "oneStep")
 235       .concat(super.getSlideNJumpMoves([x, y], V.steps[V.BISHOP]))
 236     );
 237   }
 238
 239   isAttacked(sq, color) {
 240     if (color == 'w') return super.isAttacked(sq, 'w');
 241     return (
 242       this.isAttackedByHoplite(sq) ||
 243       super.isAttackedByKing(sq, 'b') ||
 244       this.isAttackedByLieutenant(sq) ||
 245       this.isAttackedByGeneral(sq) ||
 246       this.isAttackedByCaptain(sq) ||
 247       this.isAttackedByWarlord(sq)
 248     );
 249   }
 250
 251   isAttackedByHoplite(sq) {
 252     return super.isAttackedBySlideNJump(sq, 'b', V.PAWN, [[-1,0]], "oneStep");
 253   }
 254
 255   isAttackedByLieutenant(sq) {
 256     const steps = V.steps[V.BISHOP].concat(V.steps['a']);
 257     return (
 258       super.isAttackedBySlideNJump(sq, 'b', V.LIEUTENANT, steps, "oneStep")
 259     );
 260   }
 261
 262   isAttackedByCaptain(sq) {
 263     const steps = V.steps[V.ROOK].concat(V.steps['d']);
 264     return super.isAttackedBySlideNJump(sq, 'b', V.CAPTAIN, steps, "oneStep");
 265   }
 266
 267   isAttackedByGeneral(sq) {
 268     return (
 269       super.isAttackedBySlideNJump(
 270         sq, 'b', V.GENERAL, V.steps[V.BISHOP], "oneStep") ||
 271       super.isAttackedBySlideNJump(sq, 'b', V.GENERAL, V.steps[V.ROOK])
 272     );
 273   }
 274
 275   isAttackedByWarlord(sq) {
 276     return (
 277       super.isAttackedBySlideNJump(
 278         sq, 'b', V.WARLORD, V.steps[V.KNIGHT], "oneStep") ||
 279       super.isAttackedBySlideNJump(sq, 'b', V.WARLORD, V.steps[V.BISHOP])
 280     );
 281   }
 282
 283   updateCastleFlags(move, piece) {
 284     // Only white can castle:
 285     const firstRank = 7;
 286     if (piece == V.KING && move.appear[0].c == 'w')
 287       this.castleFlags['w'] = [8, 8];
 288     else if (
 289       move.start.x == firstRank &&
 290       this.castleFlags['w'].includes(move.start.y)
 291     ) {
 292       const flagIdx = (move.start.y == this.castleFlags['w'][0] ? 0 : 1);
 293       this.castleFlags['w'][flagIdx] = 8;
 294     }
 295     else if (
 296       move.end.x == firstRank &&
 297       this.castleFlags['w'].includes(move.end.y)
 298     ) {
 299       const flagIdx = (move.end.y == this.castleFlags['w'][0] ? 0 : 1);
 300       this.castleFlags['w'][flagIdx] = 8;
 301     }
 302   }
 303
 304   postPlay(move) {
 305     if (move.vanish[0].c == 'w') super.postPlay(move);
 306   }
 307
 308   postUndo(move) {
 309     if (move.vanish[0].c == 'w') super.postUndo(move);
 310   }
 311
 312   getKingsPos() {
 313     let kings = [];
 314     for (let i=0; i<8; i++) {
 315       for (let j=0; j<8; j++) {
 316         if (
 317           this.board[i][j] != V.EMPTY &&
 318           this.getColor(i, j) == 'b' &&
 319           this.getPiece(i, j) == V.KING
 320         ) {
 321           kings.push({ x: i, y: j });
 322         }
 323       }
 324     }
 325     return kings;
 326   }
 327
 328   getCheckSquares() {
 329     if (this.turn == 'w') return super.getCheckSquares();
 330     const kings = this.getKingsPos();
 331     let res = [];
 332     for (let i of [0, 1]) {
 333       if (
 334         kings.length >= i+1 &&
 335         super.isAttacked([kings[i].x, kings[i].y], 'w')
 336       ) {
 337         res.push([kings[i].x, kings[i].y]);
 338       }
 339     }
 340     return res;
 341   }
 342
 343   filterValid(moves) {
 344     if (moves.length == 0) return [];
 345     const color = moves[0].vanish[0].c;
 346     if (color == 'w') return super.filterValid(moves);
 347     // Black moves: check if both kings under attack
 348     // If yes, moves must remove at least one attack.
 349     const kings = this.getKingsPos();
 350     return moves.filter(m => {
 351       this.play(m);
 352       let attacks = 0;
 353       for (let k of kings) {
 354         const curKingPos =
 355           this.board[k.x][k.y] == V.EMPTY
 356             ? [m.appear[0].x, m.appear[0].y] //king moved
 357             : [k.x, k.y]
 358         if (super.isAttacked(curKingPos, 'w')) attacks++;
 359         else break; //no need to check further
 360       }
 361       this.undo(m);
 362       return (
 363         (kings.length == 2 && attacks <= 1) ||
 364         (kings.length == 1 && attacks == 0)
 365       );
 366     });
 367   }
 368
 369   getCurrentScore() {
 370     if (this.turn == 'w') return super.getCurrentScore();
 371     if (super.atLeastOneMove()) return "*";
 372     // Count kings on board
 373     const kings = this.getKingsPos();
 374     if (
 375       super.isAttacked([kings[0].x, kings[0].y], 'w') ||
 376       (kings.length == 2 && super.isAttacked([kings[1].x, kings[1].y], 'w'))
 377     ) {
 378       return "1-0";
 379     }
 380     return "1/2"; //stalemate
 381   }
 382
 383   static get VALUES() {
 384     return Object.assign(
 385       {},
 386       ChessRules.VALUES,
 387       {
 388         l: 3,
 389         g: 7,
 390         c: 3,
 391         w: 7
 392       }
 393     );
 394   }
 395
 396   static get SEARCH_DEPTH() {
 397     return 2;
 398   }
 399
 400   getNotation(move) {
 401     const piece = this.getPiece(move.start.x, move.start.y);
 402     if (piece == V.PAWN) {
 403       // Pawn move
 404       const finalSquare = V.CoordsToSquare(move.end);
 405       let notation = "";
 406       if (move.vanish.length == 2)
 407         // Capture
 408         notation = "Px" + finalSquare;
 409       else {
 410         // No capture: indicate the initial square for potential ambiguity
 411         const startSquare = V.CoordsToSquare(move.start);
 412         notation = startSquare + finalSquare;
 413       }
 414       if (move.appear[0].p != V.PAWN)
 415         // Promotion
 416         notation += "=" + move.appear[0].p.toUpperCase();
 417       return notation;
 418     }
 419     return super.getNotation(move); //OK for all other pieces
 420   }
 421
 422 };