/******************************************************************************
* *
* This file is part of Kokopu, a JavaScript chess library. *
* Copyright (C) 2018-2022 Yoann Le Montagner <yo35 -at- melix.net> *
* *
* This program is free software: you can redistribute it and/or *
* modify it under the terms of the GNU Lesser General Public License *
* as published by the Free Software Foundation, either version 3 of *
* the License, or (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General *
* Public License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
* *
******************************************************************************/
'use strict';
var bt = require('./basetypes');
var exception = require('./exception');
var CASTLING_FLAG = 0x01;
var EN_PASSANT_FLAG = 0x02;
var CAPTURE_FLAG = 0x04;
var PROMOTION_FLAG = 0x08;
exports.make = function(from, to, color, movingPiece, capturedPiece) {
var flags = capturedPiece >= 0 ? CAPTURE_FLAG : 0x00;
var movingColoredPiece = movingPiece*2 + color;
return new MoveDescriptor(flags, from, to, movingColoredPiece, movingColoredPiece, capturedPiece, -1, -1);
};
exports.makeCastling = function(from, to, rookFrom, rookTo, color) {
var movingKing = bt.KING*2 + color;
var movingRook = bt.ROOK*2 + color;
return new MoveDescriptor(CASTLING_FLAG, from, to, movingKing, movingKing, movingRook, rookFrom, rookTo);
};
exports.makeEnPassant = function(from, to, enPassantSquare, color) {
var flags = EN_PASSANT_FLAG | CAPTURE_FLAG;
var movingPawn = bt.PAWN*2 + color;
var capturedPawn = bt.PAWN*2 + 1 - color;
return new MoveDescriptor(flags, from, to, movingPawn, movingPawn, capturedPawn, enPassantSquare, -1);
};
exports.makePromotion = function(from, to, color, promotion, capturedPiece) {
var flags = PROMOTION_FLAG | (capturedPiece >= 0 ? CAPTURE_FLAG : 0x00);
var movingPawn = bt.PAWN*2 + color;
var finalPiece = promotion*2 + color;
return new MoveDescriptor(flags, from, to, movingPawn, finalPiece, capturedPiece, -1, -1);
};
/**
* @class
* @classdesc Describe a legal chess move, with its characteristics.
*
* @description This constructor is not exposed in the public Kokopu API. Only internal objects and functions
* are allowed to instantiate {@link MoveDescriptor} objects.
*/
function MoveDescriptor(flags, from, to, movingPiece, finalPiece, optionalPiece, optionalSquare1, optionalSquare2) {
this._type = flags ;
this._from = from ;
this._to = to ;
this._movingPiece = movingPiece ;
this._finalPiece = finalPiece ;
this._optionalPiece = optionalPiece ; // Captured piece in case of capture, moving rook in case of castling.
this._optionalSquare1 = optionalSquare1; // Rook-from or en-passant square.
this._optionalSquare2 = optionalSquare2; // Rook-to.
}
/**
* Whether the given object is a {@link MoveDescriptor} or not.
*
* @param {Object} obj
* @returns {boolean}
*/
exports.isMoveDescriptor = function(obj) {
return obj instanceof MoveDescriptor;
};
MoveDescriptor.prototype.toString = function() {
var result = bt.squareToString(this._from) + bt.squareToString(this._to);
if(this.isPromotion()) {
result += this.promotion().toUpperCase();
}
else if(this.isCastling()) {
result += 'O';
}
return result;
};
/**
* Whether or not the current move is a castling move.
*
* @returns {boolean}
*/
MoveDescriptor.prototype.isCastling = function() {
return (this._type & CASTLING_FLAG) !== 0;
};
/**
* Whether or not the current move is a *en-passant* move.
*
* @returns {boolean}
*/
MoveDescriptor.prototype.isEnPassant = function() {
return (this._type & EN_PASSANT_FLAG) !== 0;
};
/**
* Whether or not the current move is a capture (either a regular capture or a *en-passant* capture).
*
* @returns {boolean}
*/
MoveDescriptor.prototype.isCapture = function() {
return (this._type & CAPTURE_FLAG) !== 0;
};
/**
* Whether or not the current move is a promotion.
*
* @returns {boolean}
*/
MoveDescriptor.prototype.isPromotion = function() {
return (this._type & PROMOTION_FLAG) !== 0;
};
/**
* Origin square of the moving piece. In case of castling, this is the origin square of the king.
*
* @returns {Square}
*/
MoveDescriptor.prototype.from = function() {
return bt.squareToString(this._from);
};
/**
* Destination square of the moving piece. In case of castling, this is the destination square of the king.
*
* @returns {Square}
*/
MoveDescriptor.prototype.to = function() {
return bt.squareToString(this._to);
};
/**
* Color of the moving piece.
*
* @returns {Color}
*/
MoveDescriptor.prototype.color = function() {
return bt.colorToString(this._movingPiece % 2);
};
/**
* Type of the moving piece. In case of castling, the moving piece is considered to be the king.
*
* @returns {Piece}
*/
MoveDescriptor.prototype.movingPiece = function() {
return bt.pieceToString(Math.floor(this._movingPiece / 2));
};
/**
* Color and type of the moving piece. In case of castling, the moving piece is considered to be the king.
*
* @returns {ColoredPiece}
*/
MoveDescriptor.prototype.movingColoredPiece = function() {
return bt.coloredPieceToString(this._movingPiece);
};
/**
* Type of the captured piece.
*
* @returns {Piece}
* @throws {module:exception.IllegalArgument} If the current move is not a capture (see {@link MoveDescriptor#isCapture}).
*/
MoveDescriptor.prototype.capturedPiece = function() {
if(!this.isCapture()) { throw new exception.IllegalArgument('MoveDescriptor#capturedPiece()'); }
return bt.pieceToString(Math.floor(this._optionalPiece / 2));
};
/**
* Color and type of the captured piece.
*
* @returns {ColoredPiece}
* @throws {module:exception.IllegalArgument} If the current move is not a capture (see {@link MoveDescriptor#isCapture}).
*/
MoveDescriptor.prototype.capturedColoredPiece = function() {
if(!this.isCapture()) { throw new exception.IllegalArgument('MoveDescriptor#capturedColoredPiece()'); }
return bt.coloredPieceToString(this._optionalPiece);
};
/**
* Origin square of the rook, in case of a castling move.
*
* @returns {Square}
* @throws {module:exception.IllegalArgument} If the current move is not a castling move (see {@link MoveDescriptor#isCastling}).
*/
MoveDescriptor.prototype.rookFrom = function() {
if(!this.isCastling()) { throw new exception.IllegalArgument('MoveDescriptor#rookFrom()'); }
return bt.squareToString(this._optionalSquare1);
};
/**
* Destination square of the rook, in case of a castling move.
*
* @returns {Square}
* @throws {module:exception.IllegalArgument} If the current move is not a castling move (see {@link MoveDescriptor#isCastling}).
*/
MoveDescriptor.prototype.rookTo = function() {
if(!this.isCastling()) { throw new exception.IllegalArgument('MoveDescriptor#rookTo()'); }
return bt.squareToString(this._optionalSquare2);
};
/**
* Square containing the captured pawn, in case of a *en-passant* move.
*
* @returns {Square}
* @throws {module:exception.IllegalArgument} If the current move is not a *en-passant* move (see {@link MoveDescriptor#isEnPassant}).
*/
MoveDescriptor.prototype.enPassantSquare = function() {
if(!this.isEnPassant()) { throw new exception.IllegalArgument('MoveDescriptor#enPassantSquare()'); }
return bt.squareToString(this._optionalSquare1);
};
/**
* Type of the promoted piece, in case of a promotion.
*
* @returns {Piece}
* @throws {module:exception.IllegalArgument} If the current move is not a promotion (see {@link MoveDescriptor#isPromotion}).
*/
MoveDescriptor.prototype.promotion = function() {
if(!this.isPromotion()) { throw new exception.IllegalArgument('MoveDescriptor#promotion()'); }
return bt.pieceToString(Math.floor(this._finalPiece / 2));
};
/**
* Color and type of the promoted piece, in case of a promotion.
*
* @returns {ColoredPiece}
* @throws {module:exception.IllegalArgument} If the current move is not a promotion (see {@link MoveDescriptor#isPromotion}).
*/
MoveDescriptor.prototype.coloredPromotion = function() {
if(!this.isPromotion()) { throw new exception.IllegalArgument('MoveDescriptor#coloredPromotion()'); }
return bt.coloredPieceToString(this._finalPiece);
};