/*
 * Copyright (C) 2010-2015 Matthias Heizmann (heizmann@informatik.uni-freiburg.de)
 * Copyright (C) 2009-2015 University of Freiburg
 *
 * This file is part of the ULTIMATE Automata Library.
 *
 * The ULTIMATE Automata Library 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.
 *
 * The ULTIMATE Automata Library 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 the ULTIMATE Automata Library. If not, see <http://www.gnu.org/licenses/>.
 *
 * Additional permission under GNU GPL version 3 section 7:
 * If you modify the ULTIMATE Automata Library, or any covered work, by linking
 * or combining it with Eclipse RCP (or a modified version of Eclipse RCP),
 * containing parts covered by the terms of the Eclipse Public License, the
 * licensors of the ULTIMATE Automata Library grant you additional permission
 * to convey the resulting work.
 */
package de.uni_freiburg.informatik.ultimate.automata.petrinet.visualization;

import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.Queue;
import java.util.Set;

import de.uni_freiburg.informatik.ultimate.automata.petrinet.IPetriNet;
import de.uni_freiburg.informatik.ultimate.automata.petrinet.netdatastructures.Transition;

/**
 * Converter from {@link IPetriNet} to Ultimate model.
 *
 * @author Matthias Heizmann (heizmann@informatik.uni-freiburg.de)
 * @param <LETTER>
 *            symbol type
 * @param <PLACE>
 *            place content type
 */
public class PetriNetToUltimateModel<LETTER, PLACE> {
	/**
	 * @param net
	 *            Petri net.
	 * @return the initial node of the Petri net Ultimate model
	 */
	@SuppressWarnings("unchecked")
	public PetriNetInitialNode transformToUltimateModel(final IPetriNet<LETTER, PLACE> net) {
		// Hack to see something in visualization. Visualization implemented for old Petri net model where we
		// had accepting markings.
		final Collection<Collection<PLACE>> acceptingMarkings = Collections.singleton(net.getAcceptingPlaces());
		final PetriNetInitialNode graphroot = new PetriNetInitialNode(printAcceptingMarkings(acceptingMarkings));

		final Set<PLACE> initialStates = net.getInitialPlaces();

		final Map<PLACE, PlaceNode> place2placeNode = new HashMap<>();
		final Map<Transition<LETTER, PLACE>, TransitionNode> transition2transitionNode = new HashMap<>();

		final Queue<Object> queue = new LinkedList<>();

		// add all initial states to model - all are successors of the graphroot
		for (final PLACE place : initialStates) {
			queue.add(place);
			final PlaceNode placeNode = new PlaceNode(place, participatedAcceptingMarkings(place, acceptingMarkings));
			place2placeNode.put(place, placeNode);
			graphroot.connectOutgoing(placeNode);
		}

		while (!queue.isEmpty()) {
			final Object node = queue.remove();

			if (node instanceof Transition) {
				transitionHandling(acceptingMarkings, place2placeNode, transition2transitionNode, queue,
						(Transition<LETTER, PLACE>) node);
			} else {
				placeHandling(net, place2placeNode, transition2transitionNode, queue, (PLACE) node);
			}
		}
		return graphroot;
	}

	private void placeHandling(final IPetriNet<LETTER, PLACE> net, final Map<PLACE, PlaceNode> place2placeNode,
			final Map<Transition<LETTER, PLACE>, TransitionNode> transition2transitionNode, final Queue<Object> queue,
			final PLACE place) {
		final PlaceNode placeNode = place2placeNode.get(place);
		for (final Transition<LETTER, PLACE> transition : net.getSuccessors(place)) {
			TransitionNode transNode = transition2transitionNode.get(transition);
			if (transNode == null) {
				transNode = new TransitionNode(transition);
				transition2transitionNode.put(transition, transNode);
				queue.add(transition);
			}
			placeNode.connectOutgoing(transNode);
		}
	}

	private Collection<String> participatedAcceptingMarkings(final PLACE place,
			final Collection<Collection<PLACE>> acceptingMarkings) {
		final LinkedList<String> participatedAcceptingMarkings = new LinkedList<>();
		for (final Collection<PLACE> acceptingMarking : acceptingMarkings) {
			if (acceptingMarking.contains(place)) {
				addAcceptingMarkingString(participatedAcceptingMarkings, acceptingMarking);
			}
		}
		return participatedAcceptingMarkings;
	}

	private void transitionHandling(final Collection<Collection<PLACE>> acceptingMarkings,
			final Map<PLACE, PlaceNode> place2placeNode,
			final Map<Transition<LETTER, PLACE>, TransitionNode> transition2transitionNode, final Queue<Object> queue,
			final Transition<LETTER, PLACE> transition) {
		final TransitionNode transitionNode = transition2transitionNode.get(transition);
		for (final PLACE place : transition.getSuccessors()) {
			PlaceNode placeNode = place2placeNode.get(place);
			if (placeNode == null) {
				placeNode = new PlaceNode(place, participatedAcceptingMarkings(place, acceptingMarkings));
				place2placeNode.put(place, placeNode);
				queue.add(place);
			}
			transitionNode.connectOutgoing(placeNode);
		}
	}

	private Collection<String> printAcceptingMarkings(final Collection<Collection<PLACE>> acceptingMarkings) {
		final LinkedList<String> acceptingMarkingsList = new LinkedList<>();
		for (final Collection<PLACE> acceptingMarking : acceptingMarkings) {
			if (acceptingMarking.isEmpty()) {
				acceptingMarkingsList.add("{ }");
			} else {
				addAcceptingMarkingString(acceptingMarkingsList, acceptingMarking);
			}
		}
		return acceptingMarkingsList;
	}

	private void addAcceptingMarkingString(final Collection<String> participatedAcceptingMarkings,
			final Collection<PLACE> acceptingMarking) {
		final StringBuilder builder = new StringBuilder();
		builder.append("{ ");
		String comma = "";
		for (final PLACE placeInMarking : acceptingMarking) {
			builder.append(placeInMarking).append(comma);
			comma = " , ";
		}
		builder.append('}');
		participatedAcceptingMarkings.add(builder.toString());
	}
}