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

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

export const VariantRules = class AllmateRules extends ChessRules {
  static get HasEnpassant() {
    return false;
  }

  canTake(sq1, sq2) {
    return false; //Captures handled differently
  }

  getCheckSquares() {
    // No notion of check
    return [];
  }

  static GenRandInitFen() {
    return ChessRules.GenRandInitFen().replace(/ -$/, "");
  }

  getPotentialMovesFrom([x, y]) {
    let moves = super.getPotentialMovesFrom([x, y]);

    // Augment moves with "mate-captures":
    // TODO: this is coded in a highly inefficient way...
    const color = this.turn;
    const oppCol = V.GetOppCol(this.turn);
    moves.forEach(m => {
      this.play(m);

      // 1) What is attacked?
      let attacked = {};
      for (let i=0; i<V.size.x; i++) {
        for (let j=0; j<V.size.y; j++) {
          if (this.getColor(i,j) == oppCol && this.isAttacked([i,j], [color]))
            attacked[i+"_"+j] = [i,j];
        }
      }

      // 2) Among attacked pieces, which cannot escape capture?
      // Avoid "oppMoves = this.getAllValidMoves();" => infinite recursion
      outerLoop: for (let i=0; i<V.size.x; i++) {
        for (let j=0; j<V.size.y; j++) {
          if (this.getColor(i,j) == oppCol) {
            let oppMoves = [];
            switch (this.getPiece(i, j)) {
              case V.PAWN:
                oppMoves = this.getPotentialPawnMoves([i, j]);
                break;
              case V.ROOK:
                oppMoves = this.getPotentialRookMoves([i, j]);
                break;
              case V.KNIGHT:
                oppMoves = this.getPotentialKnightMoves([i, j]);
                break;
              case V.BISHOP:
                oppMoves = this.getPotentialBishopMoves([i, j]);
                break;
              case V.QUEEN:
                oppMoves = this.getPotentialQueenMoves([i, j]);
                break;
              case V.KING:
                oppMoves = this.getPotentialKingMoves([i, j]);
                break;
            }
            for (let om of oppMoves) {
              V.PlayOnBoard(this.board, om);
              Object.values(attacked).forEach(sq => {
                const origSq = [sq[0], sq[1]];
                if (om.start.x == sq[0] && om.start.y == sq[1])
                  // Piece moved:
                  sq = [om.appear[0].x, om.appear[0].y];
                if (!this.isAttacked(sq, [color]))
                  delete attacked[origSq[0]+"_"+origSq[1]];
              });
              V.UndoOnBoard(this.board, om);
              if (Object.keys(attacked).length == 0)
                // No need to explore more moves
                break outerLoop;
            }
          }
        }
      }

      // 3) Add mate-captures:
      Object.values(attacked).forEach(sq => {
        m.vanish.push(new PiPo({
          x: sq[0],
          y: sq[1],
          c: oppCol,
          p: this.getPiece(sq[0], sq[1])
        }));
      });

      this.undo(m);
    });

    return moves;
  }

  // No "under check" conditions in castling
  getCastleMoves([x, y]) {
    const c = this.getColor(x, y);
    if (x != (c == "w" ? V.size.x - 1 : 0) || y != this.INIT_COL_KING[c])
      return []; //x isn't first rank, or king has moved (shortcut)

    // Castling ?
    const oppCol = V.GetOppCol(c);
    let moves = [];
    let i = 0;
    // King, then rook:
    const finalSquares = [
      [2, 3],
      [V.size.y - 2, V.size.y - 3]
    ];
    castlingCheck: for (
      let castleSide = 0;
      castleSide < 2;
      castleSide++ //large, then small
    ) {
      if (!this.castleFlags[c][castleSide]) continue;
      // If this code is reached, rooks and king are on initial position

      // Nothing on the path of the king ? (and no checks)
      const finDist = finalSquares[castleSide][0] - y;
      let step = finDist / Math.max(1, Math.abs(finDist));
      for (let i = y; i != finalSquares[castleSide][0]; i += step) {
        if (
          this.board[x][i] != V.EMPTY &&
            // NOTE: next check is enough, because of chessboard constraints
            (this.getColor(x, i) != c ||
              ![V.KING, V.ROOK].includes(this.getPiece(x, i)))
        ) {
          continue castlingCheck;
        }
      }

      // Nothing on the path to the rook?
      step = castleSide == 0 ? -1 : 1;
      for (i = y + step; i != this.INIT_COL_ROOK[c][castleSide]; i += step) {
        if (this.board[x][i] != V.EMPTY) continue castlingCheck;
      }
      const rookPos = this.INIT_COL_ROOK[c][castleSide];

      // Nothing on final squares, except maybe king and castling rook?
      for (i = 0; i < 2; i++) {
        if (
          this.board[x][finalSquares[castleSide][i]] != V.EMPTY &&
          this.getPiece(x, finalSquares[castleSide][i]) != V.KING &&
          finalSquares[castleSide][i] != rookPos
        ) {
          continue castlingCheck;
        }
      }

      // If this code is reached, castle is valid
      moves.push(
        new Move({
          appear: [
            new PiPo({ x: x, y: finalSquares[castleSide][0], p: V.KING, c: c }),
            new PiPo({ x: x, y: finalSquares[castleSide][1], p: V.ROOK, c: c })
          ],
          vanish: [
            new PiPo({ x: x, y: y, p: V.KING, c: c }),
            new PiPo({ x: x, y: rookPos, p: V.ROOK, c: c })
          ],
          end:
            Math.abs(y - rookPos) <= 2
              ? { x: x, y: rookPos }
              : { x: x, y: y + 2 * (castleSide == 0 ? -1 : 1) }
        })
      );
    }

    return moves;
  }

  // TODO: allow pieces to "commit suicide"? (Currently yes except king)
  filterValid(moves) {
    // Remove moves which let the king mate-captured:
    if (moves.length == 0) return [];
    const color = this.turn;
    const oppCol = V.GetOppCol(color);
    return moves.filter(m => {
      let res = true;
      this.play(m);
      if (this.underCheck(color)) {
        res = false;
        const attacked = this.kingPos[color];
        // Try to find a move to escape check
        // TODO: very inefficient method.
        outerLoop: for (let i=0; i<V.size.x; i++) {
          for (let j=0; j<V.size.y; j++) {
            if (this.getColor(i,j) == color) {
              let emoves = [];
              // Artficial turn change to "play twice":
              this.turn = color;
              switch (this.getPiece(i, j)) {
                case V.PAWN:
                  emoves = this.getPotentialPawnMoves([i, j]);
                  break;
                case V.ROOK:
                  emoves = this.getPotentialRookMoves([i, j]);
                  break;
                case V.KNIGHT:
                  emoves = this.getPotentialKnightMoves([i, j]);
                  break;
                case V.BISHOP:
                  emoves = this.getPotentialBishopMoves([i, j]);
                  break;
                case V.QUEEN:
                  emoves = this.getPotentialQueenMoves([i, j]);
                  break;
                case V.KING:
                  emoves = this.getPotentialKingMoves([i, j]);
                  break;
              }
              this.turn = oppCol;
              for (let em of emoves) {
                V.PlayOnBoard(this.board, em);
                let sq = attacked;
                if (em.start.x == attacked[0] && em.start.y == attacked[1])
                  // King moved:
                  sq = [em.appear[0].x, em.appear[0].y];
                if (!this.isAttacked(sq, [oppCol]))
                  res = true;
                V.UndoOnBoard(this.board, em);
                if (res)
                  // No need to explore more moves
                  break outerLoop;
              }
            }
          }
        }
      }
      this.undo(m);
      return res;
    });
  }

  updateVariables(move) {
    super.updateVariables(move);
    if (move.vanish.length == 2 && move.appear.length == 1) {
      // Did opponent king disappeared?
      if (move.vanish.some(v => v.p == V.KING))
        this.kingPos[this.turn] = [-1, -1];
    }
  }

  unupdateVariables(move) {
    super.unupdateVariables(move);
    if (move.vanish.length == 2 && move.appear.length == 1) {
      // Did opponent king disappeared?
      const vIdx = move.vanish.findIndex(v => v.p == V.KING)
      if (vIdx >= 0)
        this.kingPos[move.vanish[vIdx].c] = [move.vanish[vIdx].x,move.vanish[vIdx].y];
    }
  }

  getCurrentScore() {
    const color = this.turn;
    const kp = this.kingPos[color];
    if (kp[0] < 0)
      // King disappeared
      return color == "w" ? "0-1" : "1-0";
    if (this.atLeastOneMove())
      return "*";
    // Kings still there, no moves:
    return "1/2";
  }

  static get SEARCH_DEPTH() {
    return 2;
  }

  getNotation(move) {
    let notation = super.getNotation(move);
    // Add a capture mark (not describing what is captured...):
    if (move.vanish.length > 1 && move.appear[0].p != V.KING) {
      if (notation.match(/^[a-h]/))
        // Pawn capture: remove "bx" in bxc4 for example
        notation = notation.substr(2);
      else
        notation = notation.replace("x","") + "X";
    }
    return notation;
  }
};
Commit	Line	Data
	1	import { ChessRules, PiPo, Move } from "@/base_rules";
	2
	3	export const VariantRules = class AllmateRules extends ChessRules {
	4	static get HasEnpassant() {
	5	return false;
	6	}
	7
	8	canTake(sq1, sq2) {
	9	return false; //Captures handled differently
	10	}
	11
	12	getCheckSquares() {
	13	// No notion of check
	14	return [];
	15	}
	16
	17	static GenRandInitFen() {
	18	return ChessRules.GenRandInitFen().replace(/ -$/, "");
	19	}
	20
	21	getPotentialMovesFrom([x, y]) {
	22	let moves = super.getPotentialMovesFrom([x, y]);
	23
	24	// Augment moves with "mate-captures":
	25	// TODO: this is coded in a highly inefficient way...
	26	const color = this.turn;
	27	const oppCol = V.GetOppCol(this.turn);
	28	moves.forEach(m => {
	29	this.play(m);
	30
	31	// 1) What is attacked?
	32	let attacked = {};
	33	for (let i=0; i<V.size.x; i++) {
	34	for (let j=0; j<V.size.y; j++) {
	35	if (this.getColor(i,j) == oppCol && this.isAttacked([i,j], [color]))
	36	attacked[i+"_"+j] = [i,j];
	37	}
	38	}
	39
	40	// 2) Among attacked pieces, which cannot escape capture?
	41	// Avoid "oppMoves = this.getAllValidMoves();" => infinite recursion
	42	outerLoop: for (let i=0; i<V.size.x; i++) {
	43	for (let j=0; j<V.size.y; j++) {
	44	if (this.getColor(i,j) == oppCol) {
	45	let oppMoves = [];
	46	switch (this.getPiece(i, j)) {
	47	case V.PAWN:
	48	oppMoves = this.getPotentialPawnMoves([i, j]);
	49	break;
	50	case V.ROOK:
	51	oppMoves = this.getPotentialRookMoves([i, j]);
	52	break;
	53	case V.KNIGHT:
	54	oppMoves = this.getPotentialKnightMoves([i, j]);
	55	break;
	56	case V.BISHOP:
	57	oppMoves = this.getPotentialBishopMoves([i, j]);
	58	break;
	59	case V.QUEEN:
	60	oppMoves = this.getPotentialQueenMoves([i, j]);
	61	break;
	62	case V.KING:
	63	oppMoves = this.getPotentialKingMoves([i, j]);
	64	break;
	65	}
	66	for (let om of oppMoves) {
	67	V.PlayOnBoard(this.board, om);
	68	Object.values(attacked).forEach(sq => {
	69	const origSq = [sq[0], sq[1]];
	70	if (om.start.x == sq[0] && om.start.y == sq[1])
	71	// Piece moved:
	72	sq = [om.appear[0].x, om.appear[0].y];
	73	if (!this.isAttacked(sq, [color]))
	74	delete attacked[origSq[0]+"_"+origSq[1]];
	75	});
	76	V.UndoOnBoard(this.board, om);
	77	if (Object.keys(attacked).length == 0)
	78	// No need to explore more moves
	79	break outerLoop;
	80	}
	81	}
	82	}
	83	}
	84
	85	// 3) Add mate-captures:
	86	Object.values(attacked).forEach(sq => {
	87	m.vanish.push(new PiPo({
	88	x: sq[0],
	89	y: sq[1],
	90	c: oppCol,
	91	p: this.getPiece(sq[0], sq[1])
	92	}));
	93	});
	94
	95	this.undo(m);
	96	});
	97
	98	return moves;
	99	}
	100
	101	// No "under check" conditions in castling
	102	getCastleMoves([x, y]) {
	103	const c = this.getColor(x, y);
	104	if (x != (c == "w" ? V.size.x - 1 : 0) \|\| y != this.INIT_COL_KING[c])
	105	return []; //x isn't first rank, or king has moved (shortcut)
	106
	107	// Castling ?
	108	const oppCol = V.GetOppCol(c);
	109	let moves = [];
	110	let i = 0;
	111	// King, then rook:
	112	const finalSquares = [
	113	[2, 3],
	114	[V.size.y - 2, V.size.y - 3]
	115	];
	116	castlingCheck: for (
	117	let castleSide = 0;
	118	castleSide < 2;
	119	castleSide++ //large, then small
	120	) {
	121	if (!this.castleFlags[c][castleSide]) continue;
	122	// If this code is reached, rooks and king are on initial position
	123
	124	// Nothing on the path of the king ? (and no checks)
	125	const finDist = finalSquares[castleSide][0] - y;
	126	let step = finDist / Math.max(1, Math.abs(finDist));
	127	for (let i = y; i != finalSquares[castleSide][0]; i += step) {
	128	if (
	129	this.board[x][i] != V.EMPTY &&
	130	// NOTE: next check is enough, because of chessboard constraints
	131	(this.getColor(x, i) != c \|\|
	132	![V.KING, V.ROOK].includes(this.getPiece(x, i)))
	133	) {
	134	continue castlingCheck;
	135	}
	136	}
	137
	138	// Nothing on the path to the rook?
	139	step = castleSide == 0 ? -1 : 1;
	140	for (i = y + step; i != this.INIT_COL_ROOK[c][castleSide]; i += step) {
	141	if (this.board[x][i] != V.EMPTY) continue castlingCheck;
	142	}
	143	const rookPos = this.INIT_COL_ROOK[c][castleSide];
	144
	145	// Nothing on final squares, except maybe king and castling rook?
	146	for (i = 0; i < 2; i++) {
	147	if (
	148	this.board[x][finalSquares[castleSide][i]] != V.EMPTY &&
	149	this.getPiece(x, finalSquares[castleSide][i]) != V.KING &&
	150	finalSquares[castleSide][i] != rookPos
	151	) {
	152	continue castlingCheck;
	153	}
	154	}
	155
	156	// If this code is reached, castle is valid
	157	moves.push(
	158	new Move({
	159	appear: [
	160	new PiPo({ x: x, y: finalSquares[castleSide][0], p: V.KING, c: c }),
	161	new PiPo({ x: x, y: finalSquares[castleSide][1], p: V.ROOK, c: c })
	162	],
	163	vanish: [
	164	new PiPo({ x: x, y: y, p: V.KING, c: c }),
	165	new PiPo({ x: x, y: rookPos, p: V.ROOK, c: c })
	166	],
	167	end:
	168	Math.abs(y - rookPos) <= 2
	169	? { x: x, y: rookPos }
	170	: { x: x, y: y + 2 * (castleSide == 0 ? -1 : 1) }
	171	})
	172	);
	173	}
	174
	175	return moves;
	176	}
	177
	178	// TODO: allow pieces to "commit suicide"? (Currently yes except king)
	179	filterValid(moves) {
	180	// Remove moves which let the king mate-captured:
	181	if (moves.length == 0) return [];
	182	const color = this.turn;
	183	const oppCol = V.GetOppCol(color);
	184	return moves.filter(m => {
	185	let res = true;
	186	this.play(m);
	187	if (this.underCheck(color)) {
	188	res = false;
	189	const attacked = this.kingPos[color];
	190	// Try to find a move to escape check
	191	// TODO: very inefficient method.
	192	outerLoop: for (let i=0; i<V.size.x; i++) {
	193	for (let j=0; j<V.size.y; j++) {
	194	if (this.getColor(i,j) == color) {
	195	let emoves = [];
	196	// Artficial turn change to "play twice":
	197	this.turn = color;
	198	switch (this.getPiece(i, j)) {
	199	case V.PAWN:
	200	emoves = this.getPotentialPawnMoves([i, j]);
	201	break;
	202	case V.ROOK:
	203	emoves = this.getPotentialRookMoves([i, j]);
	204	break;
	205	case V.KNIGHT:
	206	emoves = this.getPotentialKnightMoves([i, j]);
	207	break;
	208	case V.BISHOP:
	209	emoves = this.getPotentialBishopMoves([i, j]);
	210	break;
	211	case V.QUEEN:
	212	emoves = this.getPotentialQueenMoves([i, j]);
	213	break;
	214	case V.KING:
	215	emoves = this.getPotentialKingMoves([i, j]);
	216	break;
	217	}
	218	this.turn = oppCol;
	219	for (let em of emoves) {
	220	V.PlayOnBoard(this.board, em);
	221	let sq = attacked;
	222	if (em.start.x == attacked[0] && em.start.y == attacked[1])
	223	// King moved:
	224	sq = [em.appear[0].x, em.appear[0].y];
	225	if (!this.isAttacked(sq, [oppCol]))
	226	res = true;
	227	V.UndoOnBoard(this.board, em);
	228	if (res)
	229	// No need to explore more moves
	230	break outerLoop;
	231	}
	232	}
	233	}
	234	}
	235	}
	236	this.undo(m);
	237	return res;
	238	});
	239	}
	240
	241	updateVariables(move) {
	242	super.updateVariables(move);
	243	if (move.vanish.length == 2 && move.appear.length == 1) {
	244	// Did opponent king disappeared?
	245	if (move.vanish.some(v => v.p == V.KING))
	246	this.kingPos[this.turn] = [-1, -1];
	247	}
	248	}
	249
	250	unupdateVariables(move) {
	251	super.unupdateVariables(move);
	252	if (move.vanish.length == 2 && move.appear.length == 1) {
	253	// Did opponent king disappeared?
	254	const vIdx = move.vanish.findIndex(v => v.p == V.KING)
	255	if (vIdx >= 0)
	256	this.kingPos[move.vanish[vIdx].c] = [move.vanish[vIdx].x,move.vanish[vIdx].y];
	257	}
	258	}
	259
	260	getCurrentScore() {
	261	const color = this.turn;
	262	const kp = this.kingPos[color];
	263	if (kp[0] < 0)
	264	// King disappeared
	265	return color == "w" ? "0-1" : "1-0";
	266	if (this.atLeastOneMove())
	267	return "*";
	268	// Kings still there, no moves:
	269	return "1/2";
	270	}
	271
	272	static get SEARCH_DEPTH() {
	273	return 2;
	274	}
	275
	276	getNotation(move) {
	277	let notation = super.getNotation(move);
	278	// Add a capture mark (not describing what is captured...):
	279	if (move.vanish.length > 1 && move.appear[0].p != V.KING) {
	280	if (notation.match(/^[a-h]/))
	281	// Pawn capture: remove "bx" in bxc4 for example
	282	notation = notation.substr(2);
	283	else
	284	notation = notation.replace("x","") + "X";
	285	}
	286	return notation;
	287	}
	288	};