package org.lcsim.detector.converter.lcdd;
   
   import static org.lcsim.units.clhep.SystemOfUnits.cm3;
   import static org.lcsim.units.clhep.SystemOfUnits.g;
   
   import org.jdom.Element;
   import org.jdom.JDOMException;
   import org.lcsim.detector.converter.XMLConverter;
   import org.lcsim.detector.material.IMaterial;
  import org.lcsim.detector.material.MaterialElement;
  import org.lcsim.detector.material.MaterialMixture;
  import org.lcsim.detector.material.MaterialStore;
  
  /**
   * 
   * This converter takes a GDML element and converts
   * it to a MaterialMixture.
   * 
   * @author Jeremy McCormick <jeremym@slac.stanford.edu>
   */
  public class MaterialMixtureConverter 
  implements XMLConverter
  {	
  	private static final String compositeStr = "composite";
  	private static final String fractionStr = "fraction";
  	
  	public void convert(Element element) throws JDOMException
  	{
  		if ( element.getName().equals("material"))
  		{
  			String name = element.getAttributeValue("name");
  						
  			if ( element.getChild("D") != null)
  			{
  				Element D = element.getChild("D");
  				//double unit = g / cm3;
  				//if ( D.getAttribute("unit") != null)
  				//{
  				//	unit = D.getAttribute("unit").getDoubleValue();
  				//}
  				
  				if ( D.getAttribute("value") != null )
  				{
  					double density = D.getAttribute("value").getDoubleValue();
  					//density *= unit;
  														
  					String defType = "";
  					
  					boolean hasComposite = ( element.getChild("composite") != null);
  					boolean hasFraction = ( element.getChild("fraction") != null);
  					
  					if ( hasComposite && hasFraction )
  					{
  						throw new JDOMException("The material <"+name+"> has both <composite> and <fraction> components, which is not allowed!");
  					}
  					
  					if ( hasComposite )
  					{
  						
  						defType = compositeStr;
  					}
  					else if ( hasFraction )
  					{
  						defType = fractionStr;
  					}
  					else {
  						throw new JDOMException("MaterialMixture <" + name + "> is missing at least one <composite> or <fraction> component.");
  					}
  					
  					int ncomponents = element.getChildren(defType).size();
  					
  					MaterialMixture material = 
  						new MaterialMixture(
  				    		name,
  				            ncomponents,
  				            density,
  				            IMaterial.Unknown
  				            );				   						
  					
  					// Add by number of atoms.
  					if ( hasComposite )
  					{
  						for ( Object obj : element.getChildren("composite"))
  						{
  							Element composite = (Element)obj;
  							IMaterial matlkp = 
  								MaterialStore.getInstance().get(composite.getAttributeValue("ref"));
                                                          
  							if ( matlkp == null )
  							{
  								throw new JDOMException("The material <" + composite.getAttributeValue("ref") + "> was not found!");
  							}
  							
  							int n = composite.getAttribute("n").getIntValue();
  							
  							if ( matlkp instanceof MaterialElement )
  							{
  								material.addElement((MaterialElement)matlkp, n);
  							}
 							else if ( matlkp instanceof MaterialMixture )
 							{
 								material.addMaterial((MaterialMixture)matlkp, n);
 							}							
 						}
 					}  
 					// Add by mass fraction.
 					// Already checked for neither or both.
 					else {
 						for ( Object obj : element.getChildren("fraction"))
 						{
 							Element fraction = (Element)obj;
                             
 							IMaterial matlkp =
 								MaterialStore.getInstance().get(fraction.getAttributeValue("ref"));                                                      
                                                                                     
 							if ( matlkp == null )
 							{
 								throw new JDOMException("The material <" + fraction.getAttributeValue("ref") + "> was not found!");
 							}
 							
 							double f = fraction.getAttribute("n").getDoubleValue();
 							
 							if ( matlkp instanceof MaterialElement )
 							{
 								material.addElement((MaterialElement)matlkp, f);
 							}
 							else if ( matlkp instanceof MaterialMixture )
 							{
 								material.addElement((MaterialMixture)matlkp, f);
 							}
 						}
 					}
 				}
 				else {
 					throw new JDOMException("The material <" + name + " is missing a density value.");
 				}
 				
 			}
 			else {
 				throw new JDOMException("The material <" + name + "> is missing <D>.");
 			}					
 		}
 		else {
 			throw new JDOMException("Invalid element <" + element.getName() + "> for MaterialMixtureConverter.");
 		}
 	}	
 }
 
 /*
 
 --Examples--
 
 <material name="Air">
 <D type="density" unit="g/cm3" value="0.0012"/>
 <fraction n="0.754" ref="N"/>
 <fraction n="0.234" ref="O"/>
 <fraction n="0.012" ref="Ar"/>
 </material>
 
 <material name="Actinium">
 <D type="density" unit="g/cm3" value="10.07" />
 <composite n="1" ref="Ac" />
 </material>
 
 */