package org.lcsim.recon.calorimetry;
   
   import java.util.ArrayList;
   import java.util.List;
   
   import org.lcsim.event.EventHeader;
   import org.lcsim.event.SimCalorimeterHit;
   import org.lcsim.event.EventHeader.LCMetaData;
   import org.lcsim.event.base.BaseLCSimEvent;
  import org.lcsim.util.Driver;
  
  /**
   * Helper class to select instrumented layers in a calorimeter collection and remove all the other hits from the collection.
   * @author <a href="mailto:christian.grefe@cern.ch">Christian Grefe</a>
   *
   */
  public class CalorimeterLayerSelector extends Driver {
  
  	protected String caloCollection = "";
  	protected List<Integer> activeLayers;
  	
  	public CalorimeterLayerSelector() {
  		
  	}
  	
  	public void setCollectionName(String collectionName) {
  		this.caloCollection = collectionName;
  		this.activeLayers = new ArrayList<Integer>();
  	}
  	
  	public void setActiveLayers(int[] layers) {
  		activeLayers.clear();
  		for (int i = 0; i != layers.length; i++) {
  			activeLayers.add(layers[i]);
  		}
  	}
  	
  	@Override
  	protected void process(EventHeader event) {
  		List<SimCalorimeterHit> caloHits = new ArrayList<SimCalorimeterHit>();
  		try {
  			caloHits = event.get(SimCalorimeterHit.class, caloCollection);
  		} catch (Exception e) {
  			System.err.println("Error: Collection "+caloCollection+" does not exist.");
  			return;
  		}
  		if (this.getHistogramLevel() > HLEVEL_NORMAL) {
  			System.out.println("Removing calorimeter hits from "+caloCollection+" for all layers except:");
  			for (int layer : activeLayers) {
  				System.out.println("\tLayer "+layer);
  			}
  		}
  		
  		List<SimCalorimeterHit> hitsToKeep = new ArrayList<SimCalorimeterHit>();
  		
  		for (SimCalorimeterHit hit : caloHits) {
  			if (activeLayers.contains(hit.getLayerNumber())) {
  				hitsToKeep.add(hit);
  			}
  		}
  		
  		caloHits.clear();
  		caloHits.addAll(hitsToKeep);
  	}
  }