xchess/lib/setup-state.js

Chess Engine

export {SetupState}

import {GameState} from './game-state.js'
import {PlayState} from './movement-state.js'
import {white, Color} from './color.js'
import {GameColor} from './game-color.js'
import {Square} from './square.js'
import {Pawn} from './piece.js'
import {Castling} from './castling.js'
import {fenToState} from './fen.js'
import {IdleDrawOffer} from './draw-offer.js'

import {
	IS_EMPTY,
	IS_STRING,
	IS_OBJECT,
} from './types.js'

import {
	GAME_NOT_STARTED,
	INVALID_MOVE_COUNT,
	INVALID_FULLMOVE_NUMBER,
	INVALID_HALFMOVE_CLOCK,
	INVALID_DOUBLE_MOVE_PAWN,
	FOREIGN_PAWN,
	INVALID_GAME_CONFIG,
	PAWN_REQUERED,
	SQUARE_IS_EMPTY,
} from './errors.js'

function IS_COUNT(value){
	if(!Number.isSafeInteger(value))
		return false;
	return true;
}

function VALIDATE_MOVE_COUNT(count){
	if(IS_COUNT(count))
		return true;
	throw INVALID_MOVE_COUNT(count);
}

function VALIDATE_FULLMOVE_NUMBER(value){
	if(IS_COUNT(value))
		return true;
	throw INVALID_FULLMOVE_NUMBER(value);
}

function VALIDATE_HALFMOVE_CLOCK(value){
	if(IS_COUNT(value))
		return true;
	throw INVALID_HALFMOVE_CLOCK(value);
}

function VALIDATE_DOUBLE_MOVE_PAWN(pawn){
	if(pawn === null)
		return true;
	if(Pawn.is(pawn))
		return true;
	throw INVALID_DOUBLE_MOVE_PAWN(pawn);
}

class SetupState extends GameState {

	#gameColor = GameColor.white;
	#count = 0;
	#halfmoveClock = 0;
	#doubleMovePawn = null;
	#wk = true;
	#wq = true;
	#bk = true;
	#bq = true;

	// Config

	get color(){
		return this.#gameColor.color;
	}

	get gameColor(){
		return this.#gameColor;
	}

	get count(){
		return this.#count;
	}

	get halfmoveClock(){
		return this.#halfmoveClock;
	}

	get doubleMovePawn(){
		return this.#doubleMovePawn;
	}

	get wk(){
		return this.#wk;
	}

	get wq(){
		return this.#wq;
	}

	get bk(){
		return this.#bk;
	}

	get bq(){
		return this.#bq;
	}

	// Setup

	access(){
		// do nothing
	}

	setCount(count){
		VALIDATE_MOVE_COUNT(count);
		this.#count = Math.trunc(count);
	}

	setFullmoveNumber(value){
		VALIDATE_FULLMOVE_NUMBER(value);
		this.#count = ((Math.trunc(value) - 1) << 1) | this.color;
	}

	setHalfmoveClock(value){
		VALIDATE_HALFMOVE_CLOCK(value);
		this.#halfmoveClock = Math.trunc(value);
	}

	setColor(value){
		this.#gameColor = GameColor.from(value);
	}

	setDoubleMovePawn(pawn){
		VALIDATE_DOUBLE_MOVE_PAWN(pawn);
		if(this.board.contains(pawn))
			this.#doubleMovePawn = pawn;
		else throw FOREIGN_PAWN(pawn);
	}

	setEnPassantTarget(square){
		if(square === null){
			this.#doubleMovePawn = null;
		} else {
			const pawnAt = Square.from(square);
			const piece = this.board.get(pawnAt);
			if(!piece)
				throw SQUARE_IS_EMPTY(pawnAt);
			if(!Pawn.is(piece))
				throw PAWN_REQUERED(piece);
			this.#doubleMovePawn = piece;
		}
	}

	setWK(value){
		this.#wk = Boolean(value);
	}

	setWQ(value){
		this.#wq = Boolean(value);
	}

	setBK(value){
		this.#bk = Boolean(value);
	}

	setBQ(value){
		this.#bq = Boolean(value);
	}

	setBoard(board){
		this.game.board.setAll(board);
	}

	setCaptureList(pieceList){
		this.captureList.setAll(pieceList);
	}

	setFEN(fen){
		const {
			board,
			color,
			fullmoveNumber,
			halfmoveClock,
			doubleMovePawn,
			castling,
		} = fenToState(fen);
		this.setBoard(board);
		this.#gameColor = GameColor.from(color);
		this.setFullmoveNumber(fullmoveNumber);
		this.#halfmoveClock = halfmoveClock;
		this.#wk = castling.has('K');
		this.#wq = castling.has('Q');
		this.#bk = castling.has('k');
		this.#bq = castling.has('q');
		if(Pawn.is(doubleMovePawn))
			this.#doubleMovePawn = doubleMovePawn;
		else
			this.#doubleMovePawn = null;
	}

	setAll(config){
		if(IS_STRING(config))
			this.setFEN(config);
		else if(IS_OBJECT(config))
			this.setConfig(config);
		else if(!IS_EMPTY(config))
			throw INVALID_GAME_CONFIG(config);
	}

	setConfig({
		board = null,
		captureList = [],
		stateCounter = [],
		stateHash,
		color = white,
		count = 0,
		halfmoveClock = 0,
		enPassantTarget = null,
		doubleMovePawn = null,
		wk = true,
		wq = true,
		bk = true,
		bq = true,
	}){
		this.setBoard(board);
		this.captureList.setAll(captureList);
		this.stateCounter.setAll(stateCounter);
		this.stateCounter.delete(stateHash);
		this.setCount(count);
		this.setHalfmoveClock(halfmoveClock);
		this.setColor(color);
		this.setWK(wk);
		this.setWQ(wq);
		this.setBK(bk);
		this.setBQ(bq);
		if(doubleMovePawn)
			this.setDoubleMovePawn(doubleMovePawn);
		else if(enPassantTarget)
			this.setEnPassantTarget(enPassantTarget);
	}

	// Stat

	get status(){
		return 'setup';
	}

	get isSetup(){
		return true;
	}

	// Game Events

	play(){
		const {context, gameColor, count, halfmoveClock, doubleMovePawn} = this;
		const repetition = 0;
		const castling = Castling.from(this.context);
		const prevCastling = Castling.prevFrom(this.context);
		const drawOffer = new IdleDrawOffer(this.context);
		const state = new PlayState({
			context,
			gameColor,
			count,
			halfmoveClock,
			repetition,
			doubleMovePawn,
			castling,
			prevCastling,
			drawOffer,
		});
		this.state = state;
		this.state.execute();
		this.state.emit('play');
		this.state.trigger();
		this.first = this.state;
		return true;
	}

	forfeit(color){
		throw GAME_NOT_STARTED();
	}

	resign(color){
		throw GAME_NOT_STARTED();
	}

	draw(color){
		throw GAME_NOT_STARTED();
	}

	toDraw(color){
		throw GAME_NOT_STARTED();
	}

	flagFall(){
		throw GAME_NOT_STARTED();
	}

	move(move){
		throw GAME_NOT_STARTED();
	}

	promote(piece){
		throw GAME_NOT_STARTED();
	}
}