package org.kuali.ole.krad;
   
   import java.text.Format;
   import java.text.NumberFormat;
   import java.util.ArrayList;
   import java.util.List;
   
   import org.apache.commons.lang3.StringUtils;
   import org.apache.log4j.Logger;
  import org.kuali.rice.krad.uif.UifConstants;
  import org.kuali.rice.krad.uif.component.Component;
  import org.kuali.rice.krad.uif.container.Group;
  import org.kuali.rice.krad.uif.container.PageGroup;
  import org.kuali.rice.krad.uif.util.ObjectPropertyUtils;
  import org.kuali.rice.krad.web.form.UifFormBase;
  import org.springframework.web.context.request.RequestAttributes;
  import org.springframework.web.context.request.RequestContextHolder;
  
  /**
   * Utility class for supporting low-level KRAD optimizations.
   */
  public final class OleComponentUtils {
  
  	private static final Logger LOG = Logger.getLogger(OleComponentUtils.class);
  
  	private static ThreadLocal<Format> CURRENCY_FORMAT = new ThreadLocal<Format>() {
  		@Override
  		protected Format initialValue() {
  			return NumberFormat.getCurrencyInstance();
  		}
  	};
  
  	/**
  	 * Gets the KRAD model for the active request.
  	 * 
  	 * @return KRAD model
  	 */
  	public static Object getModel() {
  		RequestAttributes attr = RequestContextHolder.getRequestAttributes();
  		if (attr == null) {
  			return null;
  		} else {
  			return attr.getAttribute(UifConstants.REQUEST_FORM,
  					RequestAttributes.SCOPE_REQUEST);
  		}
  	}
  
  	/**
  	 * Filters items for a group that also implements OleComponentUtils.
  	 */
  	public static List<? extends Component> filterItems(
  			List<? extends Component> srcitems) {
  		if (srcitems == null) {
  			return null;
  		}
  
  		Object model = getModel();
  		if (model == null) {
  			return srcitems;
  		} else {
  			LOG.debug("Filtering based on " + model);
  		}
  
  		List<Component> items = new ArrayList<Component>();
  		filterloop: for (Component itemComponent : srcitems) {
  
  			// Filter out OleComponent instances matching true
  			if (itemComponent instanceof OleComponent) {
  				OleComponent oleComp = (OleComponent) itemComponent;
  				String filterProp = oleComp.getFilterModelProperty();
  				Object filterVal = filterProp == null ? null
  						: ObjectPropertyUtils.getPropertyValue(model,
  								filterProp);
  				if (Boolean.TRUE.equals(filterVal)) {
  					LOG.debug("Omitting " + itemComponent.getClass() + " "
  							+ itemComponent.getId() + ", " + filterProp
  							+ " is true");
  					continue filterloop;
  				} else {
  					LOG.debug("Keeping " + itemComponent.getClass() + " "
  							+ itemComponent.getId() + ", " + filterProp
  							+ " is true");
  				}
  			}
  
  			items.add((Component) itemComponent.copy());
  		}
  
  		return items;
  	}
  
  	/**
  	 * Filters items for a view to remove non-current pages.
  	 */
  	public static List<? extends Group> filterCurrentPage(String currentPageId,
  			List<? extends Group> srcitems) {
  		if (srcitems == null) {
  			return null;
  		}
 
 		Object model = getModel();
 		if (model == null || !(model instanceof UifFormBase))
 			return srcitems;
 
 		if (StringUtils.isEmpty(currentPageId))
 			return srcitems;
 
 		LOG.debug("Filtering view pages based on " + model + ", pageId = "
 				+ currentPageId);
 
 		List<Group> items = new ArrayList<Group>();
 		for (Group group : srcitems) {
 			String compId = group.getId();
 
 			// Filter out OleComponent instances matching true
 			if ((group instanceof PageGroup) && !currentPageId.equals(compId)) {
 				LOG.debug("Omitting " + compId + ", not current page");
 				continue;
 			} else
 				LOG.debug("Keeping " + compId
 						+ ", current page or not a PageGroup");
 
 			items.add((Group) group.copy());
 		}
 
 		return items;
 	}
 
 	/**
 	 * Convenience method for converting {@link Number} to currency string
 	 * representation with minimal overhead.
 	 * 
 	 * <p>
 	 * Intended for use in KRAD SpEL expressions, for example:
 	 * </p>
 	 * 
 	 * <pre>
 	 * @{T(org.kuali.ole.krad.OleComponentUtils).formatAsCurrency(anAmount)}
 	 * </pre>
 	 * 
 	 * @param amount
 	 *            Currency amount
 	 * @return formatted currency string
 	 */
 	public static String formatAsCurrency(Number amount) {
 		return amount == null ? "" : CURRENCY_FORMAT.get().format(amount);
 	}
 
 	private OleComponentUtils() {
 	}
 
 }