/*
 * Verrückte Turing-Maschinen — A turing complete game
 * Copyright (C) 2016 Christian Fraß <vidofnir@folksprak.org>
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

module mod_vtm_aufbau
	{
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export class klasse_leser
			implements schnittstelle_aktor
			{
				
				/**
				 * @author kcf <vidofnir@folksprak.org>
				 */
				private richtung : typ_richtung;
				
				
				/**
				 * @author kcf <vidofnir@folksprak.org>
				 */
				private symbol_links : typ_symbol;
				
				
				/**
				 * @author kcf <vidofnir@folksprak.org>
				 */
				private symbol_rechts : typ_symbol;
				
				
				/**
				 * @author kcf <vidofnir@folksprak.org>
				 */
				public constructor(richtung : typ_richtung = 0, symbol_links : typ_symbol = 0, symbol_rechts : typ_symbol = 1)
					{
						this.richtung = richtung;
						this.symbol_links = symbol_links;
						this.symbol_rechts = symbol_rechts;
					}
				
				
				/**
				 * @author kcf <vidofnir@folksprak.org>
				 */
				public richtung_lesen() : typ_richtung
					{
						return this.richtung;
					}
				
				
				/**
				 * @author kcf <vidofnir@folksprak.org>
				 */
				public symbol_links_lesen() : typ_symbol
					{
						return this.symbol_links;
					}
				
				
				/**
				 * @author kcf <vidofnir@folksprak.org>
				 */
				public symbol_rechts_lesen() : typ_symbol
					{
						return this.symbol_rechts;
					}
				
				
				/**
				 * @author kcf <vidofnir@folksprak.org>
				 * @implementation
				 */
				public drehen(inkrement : int = +1) : void
					{
						this.richtung = richtung_addieren(this.richtung, inkrement);
					}
				
				
				/**
				 * @author kcf <vidofnir@folksprak.org>
				 * @implementation
				 */
				public verwenden(figur : klasse_figur) : void
					{
						let symbol_ : schnittstelle_fehlermonade<typ_symbol> = figur.lesen();
						let summand : typ_richtung;
						if (symbol_.ist_schlicht())
							{
								let symbol : typ_symbol = symbol_.lesen();
								     if (symbol === this.symbol_links)
									{
										figur.schieben();
										summand = +2;
									}
								else if (symbol === this.symbol_rechts)
									{
										figur.schieben();
										summand = -2;
									}
								else
									{
										summand = 0;
									}
							}
						else
							{
								summand = 0;
							}
						let richtung : typ_richtung = richtung_addieren(this.richtung, summand);
						figur.bewegen(richtung);
					}
				
			}
		
	}