Draft Suction Chess

[vchess.git] / client / src / variants / Crazyhouse.js

import { ChessRules, PiPo, Move } from "@/base_rules";
import { ArrayFun } from "@/utils/array";

export const VariantRules = class CrazyhouseRules extends ChessRules {
  static IsGoodFen(fen) {
    if (!ChessRules.IsGoodFen(fen)) return false;
    const fenParsed = V.ParseFen(fen);
    // 5) Check reserves
    if (!fenParsed.reserve || !fenParsed.reserve.match(/^[0-9]{10,10}$/))
      return false;
    // 6) Check promoted array
    if (!fenParsed.promoted) return false;
    if (fenParsed.promoted == "-") return true; //no promoted piece on board
    const squares = fenParsed.promoted.split(",");
    for (let square of squares) {
      const c = V.SquareToCoords(square);
      if (c.y < 0 || c.y > V.size.y || isNaN(c.x) || c.x < 0 || c.x > V.size.x)
        return false;
    }
    return true;
  }

  static ParseFen(fen) {
    const fenParts = fen.split(" ");
    return Object.assign(ChessRules.ParseFen(fen), {
      reserve: fenParts[5],
      promoted: fenParts[6]
    });
  }

  static GenRandInitFen() {
    return ChessRules.GenRandInitFen() + " 0000000000 -";
  }

  getFen() {
    return (
      super.getFen() + " " + this.getReserveFen() + " " + this.getPromotedFen()
    );
  }

  getReserveFen() {
    let counts = new Array(10);
    for (
      let i = 0;
      i < V.PIECES.length - 1;
      i++ //-1: no king reserve
    ) {
      counts[i] = this.reserve["w"][V.PIECES[i]];
      counts[5 + i] = this.reserve["b"][V.PIECES[i]];
    }
    return counts.join("");
  }

  getPromotedFen() {
    let res = "";
    for (let i = 0; i < V.size.x; i++) {
      for (let j = 0; j < V.size.y; j++) {
        if (this.promoted[i][j]) res += V.CoordsToSquare({ x: i, y: j });
      }
    }
    if (res.length > 0) res = res.slice(0, -1);
    //remove last comma
    else res = "-";
    return res;
  }

  setOtherVariables(fen) {
    super.setOtherVariables(fen);
    const fenParsed = V.ParseFen(fen);
    // Also init reserves (used by the interface to show landable pieces)
    this.reserve = {
      w: {
        [V.PAWN]: parseInt(fenParsed.reserve[0]),
        [V.ROOK]: parseInt(fenParsed.reserve[1]),
        [V.KNIGHT]: parseInt(fenParsed.reserve[2]),
        [V.BISHOP]: parseInt(fenParsed.reserve[3]),
        [V.QUEEN]: parseInt(fenParsed.reserve[4])
      },
      b: {
        [V.PAWN]: parseInt(fenParsed.reserve[5]),
        [V.ROOK]: parseInt(fenParsed.reserve[6]),
        [V.KNIGHT]: parseInt(fenParsed.reserve[7]),
        [V.BISHOP]: parseInt(fenParsed.reserve[8]),
        [V.QUEEN]: parseInt(fenParsed.reserve[9])
      }
    };
    this.promoted = ArrayFun.init(V.size.x, V.size.y, false);
    if (fenParsed.promoted != "-") {
      for (let square of fenParsed.promoted.split(",")) {
        const [x, y] = V.SquareToCoords(square);
        this.promoted[x][y] = true;
      }
    }
  }

  getColor(i, j) {
    if (i >= V.size.x) return i == V.size.x ? "w" : "b";
    return this.board[i][j].charAt(0);
  }

  getPiece(i, j) {
    if (i >= V.size.x) return V.RESERVE_PIECES[j];
    return this.board[i][j].charAt(1);
  }

  // Used by the interface:
  getReservePpath(color, index) {
    return color + V.RESERVE_PIECES[index];
  }

  // Ordering on reserve pieces
  static get RESERVE_PIECES() {
    return [V.PAWN, V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN];
  }

  getReserveMoves([x, y]) {
    const color = this.turn;
    const p = V.RESERVE_PIECES[y];
    if (this.reserve[color][p] == 0) return [];
    let moves = [];
    const pawnShift = p == V.PAWN ? 1 : 0;
    for (let i = pawnShift; i < V.size.x - pawnShift; i++) {
      for (let j = 0; j < V.size.y; j++) {
        if (this.board[i][j] == V.EMPTY) {
          let mv = new Move({
            appear: [
              new PiPo({
                x: i,
                y: j,
                c: color,
                p: p
              })
            ],
            vanish: [],
            start: { x: x, y: y }, //a bit artificial...
            end: { x: i, y: j }
          });
          moves.push(mv);
        }
      }
    }
    return moves;
  }

  getPotentialMovesFrom([x, y]) {
    if (x >= V.size.x) {
      // Reserves, outside of board: x == sizeX(+1)
      return this.getReserveMoves([x, y]);
    }
    // Standard moves
    return super.getPotentialMovesFrom([x, y]);
  }

  getAllValidMoves() {
    let moves = super.getAllValidMoves();
    const color = this.turn;
    for (let i = 0; i < V.RESERVE_PIECES.length; i++)
      moves = moves.concat(
        this.getReserveMoves([V.size.x + (color == "w" ? 0 : 1), i])
      );
    return this.filterValid(moves);
  }

  atLeastOneMove() {
    if (!super.atLeastOneMove()) {
      // Search one reserve move
      for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
        let moves = this.filterValid(
          this.getReserveMoves([V.size.x + (this.turn == "w" ? 0 : 1), i])
        );
        if (moves.length > 0) return true;
      }
      return false;
    }
    return true;
  }

  updateVariables(move) {
    super.updateVariables(move);
    if (move.vanish.length == 2 && move.appear.length == 2) return; //skip castle
    const color = move.appear[0].c;
    if (move.vanish.length == 0) {
      this.reserve[color][move.appear[0].p]--;
      return;
    }
    move.movePromoted = this.promoted[move.start.x][move.start.y];
    move.capturePromoted = this.promoted[move.end.x][move.end.y];
    this.promoted[move.start.x][move.start.y] = false;
    this.promoted[move.end.x][move.end.y] =
      move.movePromoted ||
      (move.vanish[0].p == V.PAWN && move.appear[0].p != V.PAWN);
    if (move.capturePromoted) this.reserve[color][V.PAWN]++;
    else if (move.vanish.length == 2) this.reserve[color][move.vanish[1].p]++;
  }

  unupdateVariables(move) {
    super.unupdateVariables(move);
    if (move.vanish.length == 2 && move.appear.length == 2) return;
    const color = this.turn;
    if (move.vanish.length == 0) {
      this.reserve[color][move.appear[0].p]++;
      return;
    }
    if (move.movePromoted) this.promoted[move.start.x][move.start.y] = true;
    this.promoted[move.end.x][move.end.y] = move.capturePromoted;
    if (move.capturePromoted) this.reserve[color][V.PAWN]--;
    else if (move.vanish.length == 2) this.reserve[color][move.vanish[1].p]--;
  }

  static get SEARCH_DEPTH() {
    // High branching factor
    return 2;
  }

  evalPosition() {
    let evaluation = super.evalPosition();
    // Add reserves:
    for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
      const p = V.RESERVE_PIECES[i];
      evaluation += this.reserve["w"][p] * V.VALUES[p];
      evaluation -= this.reserve["b"][p] * V.VALUES[p];
    }
    return evaluation;
  }

  getNotation(move) {
    if (move.vanish.length > 0) return super.getNotation(move);
    // Rebirth:
    const piece =
      move.appear[0].p != V.PAWN ? move.appear[0].p.toUpperCase() : "";
    return piece + "@" + V.CoordsToSquare(move.end);
  }
};