/*
 * Copyright (c) 2005-2010 KOM – Multimedia Communications Lab
 *
 * This file is part of PeerfactSim.KOM.
 * 
 * PeerfactSim.KOM 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
 * any later version.
 * 
 * PeerfactSim.KOM 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 PeerfactSim.KOM.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package de.tud.kom.p2psim.impl.topology.movement.modularosm.transition;

import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import de.tud.kom.p2psim.api.topology.movement.SimLocationActuator;
import de.tud.kom.p2psim.impl.topology.movement.modularosm.ModularMovementModel;
import de.tud.kom.p2psim.impl.topology.movement.modularosm.attraction.IAttractionGenerator;
import de.tudarmstadt.maki.simonstrator.api.Event;
import de.tudarmstadt.maki.simonstrator.api.EventHandler;
import de.tudarmstadt.maki.simonstrator.api.Time;
import de.tudarmstadt.maki.simonstrator.api.component.sensor.location.AttractionPoint;

/**
 * With this transition strategy, nodes are roaming around {@link AttractionPoint}s that have a radius. As the {@link ModularMovementModel} 
 * uses a Gauss function to add jitter and offsets to the movement, some nodes may also roam outside of the circle's radius (this is intended to make it more realistic)
 * 
 * @author Julian Zobel
 * @version 1.0, 24.01.2019
 */
public class InAreaRoamingTransitionStrategy extends AbstractAttractionBasedTransitionStrategy implements EventHandler {

	public static enum roamingTransitionState {
		PAUSE,
		ROAMING,
		TRANSITION
	}	
	
	protected Map<SimLocationActuator, roamingTransitionState> roamingStates = new LinkedHashMap<>();
	
	protected final static int EVENT_ROAMING_PAUSE_ENDED = 2;
	
	@Override
	public void addComponent(SimLocationActuator comp) {
		this.roamingStates.put(comp, roamingTransitionState.TRANSITION);
		AttractionPoint nextAP = getNewAttractionPoint(comp);
		updateTargetAttractionPoint(comp, nextAP);
	}

	@Override
	public void reachedAttractionPoint(SimLocationActuator comp) {
		
		if(roamingStates.get(comp) == roamingTransitionState.PAUSE) {
			return;
		}
		
		// start roaming if the AP was reached 
		if(roamingStates.get(comp) == roamingTransitionState.TRANSITION) {			
			// schedule the end of the roaming phase, which will make a new transition
			Event.scheduleWithDelay(getPauseTime(), this, comp, EVENT_PAUSE_ENDED);		
		}
		
		this.roamingStates.put(comp, roamingTransitionState.PAUSE);
		// schedule roaming
		Event.scheduleWithDelay(Time.SECOND * 30, this, comp, EVENT_ROAMING_PAUSE_ENDED);	
			
	}	
	
	private void roamAroundAttractionPoint(SimLocationActuator comp) {
		if(roamingStates.get(comp) != roamingTransitionState.TRANSITION) {
			AttractionPoint currentAttractionPoint = this.assignments.get(comp);
			
			if(currentAttractionPoint == null) {
				System.err.println("AP roaming failed: no AP");
			}
			
			if(currentAttractionPoint.getRadius() > 0) 
			{
				this.roamingStates.put(comp, roamingTransitionState.ROAMING);				
				notifyListenersOfAssignmentUpdate(comp, currentAttractionPoint);
			}
		}		
	}
	
	@Override
	public void eventOccurred(Object content, int type) {
		if(type == EVENT_PAUSE_ENDED) {		
			SimLocationActuator comp = (SimLocationActuator) content;
			
			// if the transit was triggered beforehand (e.g., attraction point moved), then do nothing.
			if(roamingStates.get(comp) != roamingTransitionState.TRANSITION) {				
				this.addComponent(comp);
			}
		}		
		else if(type == EVENT_ROAMING_PAUSE_ENDED) {
			
			SimLocationActuator comp = (SimLocationActuator) content;			
			AttractionPoint currentAttractionPoint = this.assignments.get(comp);
			
			// if the attraction point was removed in the meantime, go directly to transit state
			if(currentAttractionPoint == null || !IAttractionGenerator.attractionPoints.contains(currentAttractionPoint)) {				
				this.addComponent(comp);
			}
			else {			
				this.roamAroundAttractionPoint(comp);
			}
		}
	}	
	
	
	private AttractionPoint getNewAttractionPoint(SimLocationActuator component) {		
		double score = rnd.nextDouble();		
		List<AttractionPoint> candidates = new LinkedList<>();
		for (AttractionPoint ap : IAttractionGenerator.attractionPoints) {
			
			if(ap == null) {
				continue;
			}
			
			if (ap.getWeight() >= score) {
				if(lastAssignments.get(component) == null || !ap.equals(lastAssignments.get(component))) {
					candidates.add(ap);
				}				
			}
		}
		
		if (candidates.isEmpty()) {
			candidates.addAll(IAttractionGenerator.attractionPoints);
		}
		
		AttractionPoint assignment = candidates.get(rnd.nextInt(candidates.size()));		
		return assignment;		
	}	
  
}