client/src/variants/Parachute.js

   1 import { ChessRules, PiPo, Move } from "@/base_rules";
   2
   3 export class ParachuteRules extends ChessRules {
   4   static get HasFlags() {
   5     return false;
   6   }
   7
   8   static IsGoodFen(fen) {
   9     if (!ChessRules.IsGoodFen(fen)) return false;
  10     const fenParsed = V.ParseFen(fen);
  11     // 5) Check reserves
  12     if (!fenParsed.reserve || !fenParsed.reserve.match(/^[0-9]{12,12}$/))
  13       return false;
  14     return true;
  15   }
  16
  17   static IsGoodPosition(position) {
  18     if (position.length == 0) return false;
  19     const rows = position.split("/");
  20     if (rows.length != V.size.x) return false;
  21     for (let row of rows) {
  22       let sumElts = 0;
  23       for (let i = 0; i < row.length; i++) {
  24         if (V.PIECES.includes(row[i].toLowerCase())) sumElts++;
  25         else {
  26           const num = parseInt(row[i], 10);
  27           if (isNaN(num)) return false;
  28           sumElts += num;
  29         }
  30       }
  31       if (sumElts != V.size.y) return false;
  32     }
  33     return true;
  34   }
  35
  36   static ParseFen(fen) {
  37     const fenParts = fen.split(" ");
  38     return Object.assign(
  39       ChessRules.ParseFen(fen),
  40       { reserve: fenParts[4] }
  41     );
  42   }
  43
  44   static GenRandInitFen() {
  45     // ChessRules.PIECES order is P, R, N, B, Q, K:
  46     return "8/8/8/8/8/8/8/8 w 0 - 822211822211";
  47   }
  48
  49   getFen() {
  50     return super.getFen() + " " + this.getReserveFen();
  51   }
  52
  53   getFenForRepeat() {
  54     return super.getFenForRepeat() + "_" + this.getReserveFen();
  55   }
  56
  57   getReserveFen() {
  58     let counts = new Array(12);
  59     for (let i = 0; i < V.PIECES.length; i++) {
  60       counts[i] = this.reserve["w"][V.PIECES[i]];
  61       counts[6 + i] = this.reserve["b"][V.PIECES[i]];
  62     }
  63     return counts.join("");
  64   }
  65
  66   setOtherVariables(fen) {
  67     super.setOtherVariables(fen);
  68     // Also init reserves (used by the interface to show landable pieces)
  69     const reserve =
  70       V.ParseFen(fen).reserve.split("").map(x => parseInt(x, 10));
  71     this.reserve = {
  72       w: {
  73         [V.PAWN]: reserve[0],
  74         [V.ROOK]: reserve[1],
  75         [V.KNIGHT]: reserve[2],
  76         [V.BISHOP]: reserve[3],
  77         [V.QUEEN]: reserve[4],
  78         [V.KING]: reserve[5]
  79       },
  80       b: {
  81         [V.PAWN]: reserve[6],
  82         [V.ROOK]: reserve[7],
  83         [V.KNIGHT]: reserve[8],
  84         [V.BISHOP]: reserve[9],
  85         [V.QUEEN]: reserve[10],
  86         [V.KING]: reserve[11]
  87       }
  88     };
  89   }
  90
  91   getColor(i, j) {
  92     if (i >= V.size.x) return i == V.size.x ? "w" : "b";
  93     return this.board[i][j].charAt(0);
  94   }
  95
  96   getPiece(i, j) {
  97     if (i >= V.size.x) return V.RESERVE_PIECES[j];
  98     return this.board[i][j].charAt(1);
  99   }
 100
 101   // Used by the interface:
 102   getReservePpath(index, color) {
 103     return color + V.RESERVE_PIECES[index];
 104   }
 105
 106   // Ordering on reserve pieces (matching V.PIECES order)
 107   static get RESERVE_PIECES() {
 108     return [V.PAWN, V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN, V.KING];
 109   }
 110
 111   getReserveMoves([x, y]) {
 112     const color = this.turn;
 113     const oppCol = V.GetOppCol(color);
 114     const p = V.RESERVE_PIECES[y];
 115     if (this.reserve[color][p] == 0) return [];
 116     let moves = [];
 117     let boundary =
 118       p == V.PAWN
 119         // Pawns can land only on 4 first ranks:
 120         ? (color == 'w' ? [4, 8] : [0, 4])
 121         : [0, 8];
 122     for (let i = boundary[0]; i < boundary[1]; i++) {
 123       for (let j = 0; j < 8; j++) {
 124         if (this.board[i][j] == V.EMPTY) {
 125           let mv = new Move({
 126             appear: [
 127               new PiPo({
 128                 x: i,
 129                 y: j,
 130                 c: color,
 131                 p: p
 132               })
 133             ],
 134             vanish: [],
 135             start: { x: x, y: y }, //a bit artificial...
 136             end: { x: i, y: j }
 137           });
 138           this.play(mv);
 139           // Landing with check is forbidden:
 140           if (!this.underCheck(oppCol)) moves.push(mv);
 141           this.undo(mv);
 142         }
 143       }
 144     }
 145     return moves;
 146   }
 147
 148   getPotentialMovesFrom([x, y]) {
 149     let moves =
 150       x >= 8
 151         ? this.getReserveMoves([x, y])
 152         : super.getPotentialMovesFrom([x, y]);
 153     // Forbid captures if king not landed yet:
 154     if (x < 8 && moves.length > 0 && this.kingPos[moves[0].appear[0].c][0] < 0)
 155       moves = moves.filter(m => m.vanish.length == 1);
 156     return moves;
 157   }
 158
 159   getAllValidMoves() {
 160     let moves = super.getAllValidMoves();
 161     const color = this.turn;
 162     for (let i = 0; i < V.RESERVE_PIECES.length; i++)
 163       moves = moves.concat(
 164         this.getReserveMoves([V.size.x + (color == "w" ? 0 : 1), i])
 165       );
 166     return this.filterValid(moves);
 167   }
 168
 169   isAttacked(sq, color) {
 170     // While the king hasn't landed, nothing is attacked:
 171     if (this.kingPos[color][0] < 0) return false;
 172     return super.isAttacked(sq, color);
 173   }
 174
 175   atLeastOneMove() {
 176     if (!super.atLeastOneMove()) {
 177       // Search one reserve move
 178       for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
 179         let moves = this.filterValid(
 180           this.getReserveMoves([V.size.x + (this.turn == "w" ? 0 : 1), i])
 181         );
 182         if (moves.length > 0) return true;
 183       }
 184       return false;
 185     }
 186     return true;
 187   }
 188
 189   underCheck(color) {
 190     if (this.kingPos[color][0] < 0)
 191       // A king outside the board isn't under check
 192       return false;
 193     return this.isAttacked(this.kingPos[color], V.GetOppCol(color));
 194   }
 195
 196   prePlay(move) {
 197     super.prePlay(move);
 198     if (move.vanish.length == 0) this.reserve[this.turn][move.appear[0].p]--;
 199   }
 200
 201   postUndo(move) {
 202     if (move.vanish.length == 0) this.reserve[this.turn][move.appear[0].p]++;
 203     // (Potentially) Reset king position
 204     if (move.appear[0].p == V.KING) {
 205       const c = move.appear[0].c;
 206       if (move.vanish.length == 0)
 207         // Landing king
 208         this.kingPos[c] = [-1, -1];
 209       else
 210         // King movement
 211         this.kingPos[c] = [move.start.x, move.start.y];
 212     }
 213   }
 214
 215   static get SEARCH_DEPTH() {
 216     return 1;
 217   }
 218
 219   evalPosition() {
 220     let evaluation = super.evalPosition();
 221     // Add reserves:
 222     for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
 223       const p = V.RESERVE_PIECES[i];
 224       evaluation += this.reserve["w"][p] * V.VALUES[p];
 225       evaluation -= this.reserve["b"][p] * V.VALUES[p];
 226     }
 227     return evaluation;
 228   }
 229
 230   getNotation(move) {
 231     if (move.vanish.length > 0) return super.getNotation(move);
 232     // Parachutage:
 233     const piece =
 234       move.appear[0].p != V.PAWN ? move.appear[0].p.toUpperCase() : "";
 235     return piece + "@" + V.CoordsToSquare(move.end);
 236   }
 237 };