xchess/lib/promotion-state.js

Chess Engine

export {PromotionState}

import {ProxyState} from './proxy-state.js'
import {Transitional} from './transitional-state.js'
import {PromotionEvent, MoveEvent} from './events.js'
import {PROMOTION_REQUIRED} from './errors.js'

class PromotionState extends Transitional(ProxyState) {

	#move;

	constructor(move, target, prev){
		super(target, prev);
		this.#move = move;
	}

	get lastMove(){
		return this.#move;
	}

	// Stat

	get status(){
		return 'promotion';
	}

	get isMovement(){
		return true;
	}

	get isPromotion(){
		return true;
	}

	// Log Event

	undo(){
		this.#move.undo(this.context);
	}

	redo(){
		this.#move.redo(this.context);
	}

	trigger(){
		this.dispatch(new PromotionEvent('promotion', this.#move));
	}

	// Game Events

	move(move){
		throw PROMOTION_REQUIRED();
	}

	promote(piece){
		const move = this.#move.respond(piece);
		this.dispatch(new MoveEvent('promote', move));
		this.target.do(move);
		return true;
	}
}