package nl.tudelft.goal.EIS2Java.handlers;
   
   import java.lang.reflect.InvocationTargetException;
   import java.lang.reflect.Method;
   import java.util.ArrayList;
   import java.util.Collection;
   import java.util.LinkedList;
   import java.util.List;
   
  import nl.tudelft.goal.EIS2Java.annotation.AsPercept;
  import nl.tudelft.goal.EIS2Java.translation.Filter;
  import nl.tudelft.goal.EIS2Java.util.EIS2JavaUtil;
  import eis.exceptions.EntityException;
  import eis.exceptions.PerceiveException;
  import eis.iilang.Percept;
  
  public final class SynchronizedPerceptHandler extends AbstractPerceptHandler {
  
  	/** Collection of methods on the entity */
  	protected final Collection<Method> perceptMethods;
  	protected final AsynchronousEntity entity;
  
  	public SynchronizedPerceptHandler(AsynchronousEntity entity) throws EntityException {
  		super(entity);
  		this.entity = entity;
  		this.perceptMethods = EIS2JavaUtil.processPerceptAnnotations(entity.getClass()).values();
  	}
  
  	@Override
  	public final LinkedList<Percept> getAllPercepts() throws PerceiveException {
  
  		LinkedList<Percept> percepts = new LinkedList<Percept>();
  
  		try {
  			entity.acquire();
  			try {
  				for (Method method : perceptMethods) {
  
  					percepts.addAll(getPercepts(method));
  				}
  			} finally {
  				entity.release();
  			}
  		} catch (InterruptedException e) {
  			throw new PerceiveException("Unable to perceive any percepts. Could not aquire entity.", e);
  		}
  
  		return percepts;
  	}
  
  	/**
  	 * Creates new percepts by calling the given method on the entity.
  	 * 
  	 * @param entity
  	 *            the entity to get the percept from.
  	 * @param method
  	 *            the method to invoke on the entity which must be annotated
  	 *            with {@link AsPercept}.
  	 * @return The percepts that were generated by invoking the method on the
  	 *         entity.
  	 * @throws PerceiveException
  	 *             If the percepts couldn't be retrieved.
  	 */
  	private List<Percept> getPercepts(Method method) throws PerceiveException {
  
  		// list of new objects for the percepts
  		List<Object> perceptObjects = new ArrayList<Object>();
  
  		// Optimization, don't call methods for once percepts if they have been
  		// called before.
  		AsPercept annotation = method.getAnnotation(AsPercept.class);
  		Filter.Type filter = annotation.filter();
  		if (filter != Filter.Type.ONCE || previousPercepts.get(method) == null) {
  			perceptObjects = getPerceptObjects(method);
  		}
  
  		List<Percept> percepts = translatePercepts(method, perceptObjects);
  		return percepts;
  	}
  
  	/**
  	 * Get the percept objects for given percept name, using method. CHECK why
  	 * use all these params, we can get name from the method, right?
  	 * 
  	 * @param method
  	 * @param entity
  	 * @param perceptName
  	 * @return
  	 * @throws PerceiveException
  	 */
  	private List<Object> getPerceptObjects(Method method) throws PerceiveException {
  
  		AsPercept annotation = method.getAnnotation(AsPercept.class);
  		String perceptName = annotation.name();
  
  		Object returnValue;
  		try {
  			returnValue = method.invoke(entity);
  		} catch (IllegalArgumentException e) {
 			throw new PerceiveException("Unable to perceive " + perceptName, e);
 		} catch (IllegalAccessException e) {
 			throw new PerceiveException("Unable to perceive " + perceptName, e);
 		} catch (InvocationTargetException e) {
 			throw new PerceiveException("Unable to perceive " + perceptName, e);
 		}
 
 		return unpackPerceptObject(method, returnValue);
 	}
 
 }