client/src/variants/Schess.js

   1 import { ChessRules, PiPo } from "@/base_rules";
   2
   3 export class SchessRules extends ChessRules {
   4
   5   static get PawnSpecs() {
   6     return Object.assign(
   7       {},
   8       ChessRules.PawnSpecs,
   9       {
  10         promotions:
  11           ChessRules.PawnSpecs.promotions.concat([V.HAWK, V.ELEPHANT])
  12       }
  13     );
  14   }
  15
  16   static get HAWK() {
  17     return 'h';
  18   }
  19
  20   static get ELEPHANT() {
  21     return 'e';
  22   }
  23
  24   static get NOTHING() {
  25     return 'o';
  26   }
  27
  28   static get PIECES() {
  29     return ChessRules.PIECES.concat([V.HAWK, V.ELEPHANT]);
  30   }
  31
  32   getPpath(b) {
  33     if ([V.HAWK, V.ELEPHANT, V.NOTHING].includes(b[1])) return "Schess/" + b;
  34     return b;
  35   }
  36
  37   static IsGoodFen(fen) {
  38     if (!ChessRules.IsGoodFen(fen)) return false;
  39     const fenParsed = V.ParseFen(fen);
  40     // Check pocket state
  41     if (!fenParsed.pocket || !fenParsed.pocket.match(/^[0-1]{4,4}$/))
  42       return false;
  43     return true;
  44   }
  45
  46   static IsGoodFlags(flags) {
  47     // 4 for castle + 16 for generators
  48     return !!flags.match(/^[a-z]{4,4}[01]{16,16}$/);
  49   }
  50
  51   setFlags(fenflags) {
  52     super.setFlags(fenflags); //castleFlags
  53     this.pieceFlags = {
  54       w: [...Array(8)], //pieces can generate Hawk or Elephant?
  55       b: [...Array(8)]
  56     };
  57     const flags = fenflags.substr(4); //skip first 4 letters, for castle
  58     for (let c of ["w", "b"]) {
  59       for (let i = 0; i < 8; i++)
  60         this.pieceFlags[c][i] = flags.charAt((c == "w" ? 0 : 8) + i) == "1";
  61     }
  62   }
  63
  64   aggregateFlags() {
  65     return [this.castleFlags, this.pieceFlags];
  66   }
  67
  68   disaggregateFlags(flags) {
  69     this.castleFlags = flags[0];
  70     this.pieceFlags = flags[1];
  71   }
  72
  73   static ParseFen(fen) {
  74     const fenParts = fen.split(" ");
  75     return Object.assign(
  76       ChessRules.ParseFen(fen),
  77       { pocket: fenParts[5] }
  78     );
  79   }
  80
  81   static GenRandInitFen(options) {
  82     return (
  83       ChessRules.GenRandInitFen(options).slice(0, -2) +
  84       // Add pieceFlags + pocket
  85       "1111111111111111 - 1111"
  86     );
  87   }
  88
  89   getFen() {
  90     return (
  91       super.getFen() + " " +
  92       this.getPocketFen()
  93     );
  94   }
  95
  96   getFenForRepeat() {
  97     return (
  98       super.getFenForRepeat() + "_" +
  99       this.getPocketFen()
 100     );
 101   }
 102
 103   getFlagsFen() {
 104     let fen = super.getFlagsFen();
 105     // Add pieces flags
 106     for (let c of ["w", "b"])
 107       for (let i = 0; i < 8; i++) fen += (this.pieceFlags[c][i] ? "1" : "0");
 108     return fen;
 109   }
 110
 111   getPocketFen() {
 112     let res = "";
 113     for (let c of ["w", "b"])
 114       res += this.pocket[c][V.HAWK] + this.pocket[c][V.ELEPHANT];
 115     return res;
 116   }
 117
 118   setOtherVariables(fen) {
 119     super.setOtherVariables(fen);
 120     const fenParsed = V.ParseFen(fen);
 121     this.pocket = {
 122       "w": {
 123         h: parseInt(fenParsed.pocket[0], 10),
 124         e: parseInt(fenParsed.pocket[1], 10)
 125       },
 126       "b": {
 127         h: parseInt(fenParsed.pocket[2], 10),
 128         e: parseInt(fenParsed.pocket[3], 10)
 129       }
 130     };
 131   }
 132
 133   getPotentialMovesFrom([x, y]) {
 134     let moves = undefined;
 135     switch (this.getPiece(x, y)) {
 136       case V.HAWK:
 137         moves = this.getPotentialHawkMoves([x, y]);
 138         break;
 139       case V.ELEPHANT:
 140         moves = this.getPotentialElephantMoves([x, y]);
 141         break;
 142       default:
 143         moves = super.getPotentialMovesFrom([x, y]);
 144     }
 145     // For moves presentation when choices:
 146     const unshiftNothing = (m) => {
 147       const a = m.appear[0];
 148       m.appear.unshift(new PiPo({
 149         p: V.NOTHING,
 150         c: 'o',
 151         x: a.x,
 152         y: a.y
 153       }));
 154     };
 155     // Post-processing: add choices for hawk and elephant,
 156     // except for moves letting the king under check.
 157     const color = this.turn;
 158     if (Object.values(this.pocket[color]).some(v => v > 0)) {
 159       const firstRank = (color == "w" ? 7 : 0);
 160       let validMoves = [];
 161       moves.forEach(m => {
 162         let inCheckAfter = false;
 163         this.play(m);
 164         if (this.underCheck(color)) inCheckAfter = true;
 165         this.undo(m);
 166         if (!inCheckAfter) {
 167           for (let pp of ['h', 'e']) {
 168             if (this.pocket[color][pp] > 0) {
 169               let shift = (m.appear[0].p == V.NOTHING ? 1 : 0);
 170               if (
 171                 m.start.x == firstRank &&
 172                 this.pieceFlags[color][m.start.y] &&
 173                 (
 174                   m.appear.length == shift+1 ||
 175                   // Special castle case: is initial king square free?
 176                   ![m.appear[shift].y, m.appear[shift+1].y]
 177                     .includes(m.vanish[0].y)
 178                 )
 179               ) {
 180                 let pMove = JSON.parse(JSON.stringify(m));
 181                 if (shift == 1) pMove.appear.shift();
 182                 // NOTE: unshift instead of push, for choices presentation
 183                 pMove.appear.unshift(new PiPo({
 184                   p: pp,
 185                   c: color,
 186                   x: x,
 187                   y: y
 188                 }));
 189                 validMoves.push(pMove);
 190                 if (shift == 0) unshiftNothing(m);
 191               }
 192               shift = (m.appear[0].p == V.NOTHING ? 1 : 0);
 193               if (
 194                 m.appear.length >= 2 + shift &&
 195                 m.vanish.length == 2 &&
 196                 ![m.appear[shift].y, m.appear[shift+1].y]
 197                   .includes(m.vanish[1].y)
 198               ) {
 199                 // Special castle case: rook flag was necessarily on
 200                 let pMove = JSON.parse(JSON.stringify(m));
 201                 if (shift == 1) pMove.appear.shift();
 202                 pMove.appear.unshift(new PiPo({
 203                   p: pp,
 204                   c: color,
 205                   x: m.vanish[1].x,
 206                   y: m.vanish[1].y
 207                 }));
 208                 validMoves.push(pMove);
 209                 if (shift == 0) unshiftNothing(m);
 210               }
 211             }
 212           }
 213           // Unshift, to show the empty square on the left:
 214           validMoves.unshift(m);
 215         }
 216       });
 217       moves = validMoves;
 218     }
 219     return moves;
 220   }
 221
 222   getPotentialHawkMoves(sq) {
 223     return this.getSlideNJumpMoves(sq, V.steps[V.BISHOP]).concat(
 224       this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], 1)
 225     );
 226   }
 227
 228   getPotentialElephantMoves(sq) {
 229     return this.getSlideNJumpMoves(sq, V.steps[V.ROOK]).concat(
 230       this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], 1)
 231     );
 232   }
 233
 234   isAttacked(sq, color) {
 235     return (
 236       super.isAttacked(sq, color) ||
 237       this.isAttackedByHawk(sq, color) ||
 238       this.isAttackedByElephant(sq, color)
 239     );
 240   }
 241
 242   isAttackedByHawk(sq, color) {
 243     return (
 244       this.isAttackedBySlideNJump(sq, color, V.HAWK, V.steps[V.BISHOP]) ||
 245       this.isAttackedBySlideNJump(sq, color, V.HAWK, V.steps[V.KNIGHT], 1)
 246     );
 247   }
 248
 249   isAttackedByElephant(sq, color) {
 250     return (
 251       this.isAttackedBySlideNJump(sq, color, V.ELEPHANT, V.steps[V.ROOK]) ||
 252       this.isAttackedBySlideNJump(sq, color, V.ELEPHANT, V.steps[V.KNIGHT], 1)
 253     );
 254   }
 255
 256   filterValid(moves) {
 257     if (Object.values(this.pocket[this.turn]).some(v => v > 0))
 258       // Undercheck tests done in getPotentialMovesFrom()
 259       return moves;
 260     return super.filterValid(moves);
 261   }
 262
 263   prePlay(move) {
 264     super.prePlay(move);
 265     if (move.appear.length >= 2) {
 266       if ([V.HAWK, V.ELEPHANT].includes(move.appear[0].p)) {
 267         // A pocket piece is used
 268         const color = this.turn;
 269         this.pocket[color][move.appear[0].p] = 0;
 270       }
 271     }
 272   }
 273
 274   postPlay(move) {
 275     const color = move.vanish[0].c;
 276     const piece = move.vanish[0].p;
 277     // Update king position + flags
 278     if (piece == V.KING) {
 279       const shift =
 280         ([V.HAWK, V.ELEPHANT, V.NOTHING].includes(move.appear[0].p) ? 1 : 0);
 281       this.kingPos[color][0] = move.appear[shift].x;
 282       this.kingPos[color][1] = move.appear[shift].y;
 283     }
 284     this.updateCastleFlags(move, piece);
 285
 286     const oppCol = this.turn;
 287     const firstRank = (color == 'w' ? 7 : 0);
 288     const oppFirstRank = 7 - firstRank;
 289     // Does this move turn off a piece init square flag?
 290     if (move.start.x == firstRank) {
 291       if (this.pieceFlags[color][move.start.y])
 292         this.pieceFlags[color][move.start.y] = false;
 293       // Special castle case:
 294       if (move.appear.length >= 2 && move.vanish.length == 2) {
 295         const L = move.appear.length;
 296         if (move.appear[L-1].p == V.ROOK)
 297           this.pieceFlags[color][move.vanish[1].y] = false;
 298       }
 299     }
 300     if (move.end.x == oppFirstRank && this.pieceFlags[oppCol][move.end.y])
 301       this.pieceFlags[oppCol][move.end.y] = false;
 302   }
 303
 304   postUndo(move) {
 305     super.postUndo(move);
 306     if (move.appear.length >= 2) {
 307       if ([V.HAWK, V.ELEPHANT].includes(move.appear[0].p)) {
 308         // A pocket piece was used
 309         const color = this.turn;
 310         this.pocket[color][move.appear[0].p] = 1;
 311       }
 312     }
 313   }
 314
 315   static get SEARCH_DEPTH() {
 316     return 2;
 317   }
 318
 319   static get VALUES() {
 320     return Object.assign(
 321       {
 322         'h': 5,
 323         'e': 7
 324       },
 325       ChessRules.VALUES
 326     );
 327   }
 328
 329   getNotation(move) {
 330     if (move.appear.length >= 2) {
 331       const pPieceAppear = [V.HAWK, V.ELEPHANT].includes(move.appear[0].p);
 332       const nothingAppear = (move.appear[0].p == V.NOTHING);
 333       if (pPieceAppear || nothingAppear) {
 334         let suffix = "";
 335         if (pPieceAppear) {
 336           suffix = "/" + move.appear[0].p.toUpperCase();
 337           if (move.appear.length == 3) {
 338             // Castling; indicate square
 339             suffix +=
 340               V.CoordsToSquare({ x: move.appear[0].x, y: move.appear[0].y });
 341           }
 342         }
 343         let cmove = JSON.parse(JSON.stringify(move));
 344         cmove.appear.shift();
 345         return super.getNotation(cmove) + suffix;
 346       }
 347     }
 348     return super.getNotation(move);
 349   }
 350
 351 };