package nl.tudelft.goal.ut2004.translators;
   
   import java.util.ArrayList;
   
   import nl.tudelft.goal.ut2004.messages.None;
   import nl.tudelft.goal.ut2004.messages.Percept;
   import eis.eis2java.exception.TranslationException;
   import eis.eis2java.translation.Java2Parameter;
   import eis.eis2java.translation.Translator;
  import eis.iilang.Parameter;
  import eis.iilang.ParameterList;
  
  /**
   * Translates percepts of objects to arrays such that they can be reasonably be
   * expected to match. When objects translate to multiple elements they are
   * considered to be a {@link ParameterList}. When they translate to an empty
   * list they're ignored. Single element lists are collapsed.
   * 
   * @author mpkorstanje
   * 
   */
  public class PerceptTranslator implements Java2Parameter<Percept> {
  
  	@Override
  	public Parameter[] translate(Percept percept) throws TranslationException {
  		ArrayList<Object> translated = new ArrayList<Object>(percept.size());
  		for (Object elements : percept) {
  
  			// Null elements are considered "none".
  			if (elements == null) {
  				elements = new None();
  			}
  
  			Parameter[] t = Translator.getInstance().translate2Parameter(elements);
  
  			// Collapse single and empty arrays.
  			if (t.length == 0) {
  				continue;
  			} else if (t.length == 1) {
  				translated.add(t[0]);
  			} else {
  				translated.add(new ParameterList(t));
  			}
  		}
  		return translated.toArray(new Parameter[translated.size()]);
  	}
  
  	@Override
  	public Class<? extends Percept> translatesFrom() {
  		return Percept.class;
  	}
  
  }