/*
 * 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 export function figur_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 export function figur_License for more details.
 * 
 * You should have received a copy of the GNU General export function figur_License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

module mod_vtm_aufbau
	{
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export type typ_figur =
			{
				zustand : typ_zustand;
				band : Array<typ_symbol>;
				stelle : typ_stelle;
			}
		;
		
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export function figur_erstellen
			(
				band : Array<typ_symbol> = [],
				stelle : typ_stelle = stelle_null()
			)
			: typ_figur
			{
				return {
					"zustand": zustand_laufend,
					"band": band,
					"stelle": stelle,
				};
			}
		
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export function figur_zustand_lesen
			(
				figur : typ_figur
			)
			: typ_zustand
			{
				return figur.zustand;
			}
		
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export function figur_band_lesen
			(
				figur : typ_figur
			)
			: Array<typ_symbol>
			{
				return figur.band;
			}
		
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export function figur_stelle_lesen
			(
				figur : typ_figur
			)
			: typ_stelle
			{
				return figur.stelle;
			}
		
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export function figur_bewegen
			(
				figur : typ_figur,
				richtung : typ_richtung
			)
			: void
			{
				let summand : typ_stelle = stelle_von_richtung(richtung);
				figur.stelle = stelle_addieren(figur.stelle, summand);
			}
		
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export function figur_schreiben
			(
				figur : typ_figur,
				symbol : typ_symbol
			)
			: void
			{
				figur.band.push(symbol);
			}
		
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export function figur_lesen
			(
				figur : typ_figur
			)
			: schnittstelle_fehlermonade<typ_symbol>
			{
				if (figur.band.length <= 0)
					{
						return (new klasse_nichts<typ_symbol>());
					}
				else
					{
						return (new klasse_schlicht<typ_symbol>(figur.band[0]));
					}
			}
		
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export function figur_schieben
			(
				figur : typ_figur
			)
			: void
			{
				if (figur.band.length <= 0)
					{
						let meldung : string = "Band ist leer";
						throw (new Error(meldung));
					}
				else
					{
						figur.band.shift();
					}
			}
		
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export function figur_annehmen
			(
				figur : typ_figur
			)
			: void
			{
				figur.zustand = zustand_angenommen;
			}
		
		
		/**
		 * @author kcf <vidofnir@folksprak.org>
		 */
		export function figur_verwerfen
			(
				figur : typ_figur
			)
			: void
			{
				figur.zustand = zustand_abgelehnt;
			}
		
	}