/*
    * Copyright 2007-2008 The Kuali Foundation
    *
    * Licensed under the Educational Community License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.opensource.org/licenses/ecl2.php
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.kuali.rice.kns.lookup;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.io.Writer;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.commons.lang.StringUtils;
  import org.displaytag.model.Row;
  import org.displaytag.model.TableModel;
  import org.kuali.rice.core.util.WriterOutputStream;
  import org.kuali.rice.kns.bo.BusinessObject;
  import org.kuali.rice.kns.bo.Exporter;
  import org.kuali.rice.kns.datadictionary.BusinessObjectEntry;
  import org.kuali.rice.kns.exception.KualiException;
  import org.kuali.rice.kns.service.KNSServiceLocator;
  import org.kuali.rice.kns.util.GlobalVariables;
  import org.kuali.rice.kns.web.struts.form.KualiForm;
  import org.kuali.rice.kns.web.struts.form.LookupForm;
  import org.kuali.rice.kns.web.ui.ResultRow;
  
  /**
   * A helper class to be used with the custom ExportView implementations for
   * Display Tag.  Most of the logic for interfacing with the KNS export
   * system is encapsulated in this helper class so it can be shared between
   * the various Display Tag export implementations. 
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   *
   */
  public class ExportViewHelper {
  
  	private BusinessObjectEntry businessObjectEntry;
  	private List<BusinessObject> businessObjects;
  	
  	public ExportViewHelper(TableModel tableModel) {
  		this.businessObjectEntry = loadBusinessObjectEntry();
  		this.businessObjects = loadBusinessObjects(tableModel);
  	}
  	
  	protected BusinessObjectEntry loadBusinessObjectEntry() {
  		KualiForm kualiForm = GlobalVariables.getKualiForm();
  		if (kualiForm instanceof LookupForm) {
  			LookupForm lookupForm = (LookupForm) kualiForm;
  			if (!StringUtils.isBlank(lookupForm.getBusinessObjectClassName())) {
  				return KNSServiceLocator.getDataDictionaryService().getDataDictionary().getBusinessObjectEntry(lookupForm.getBusinessObjectClassName());
  			}
  		}
  		return null;
  	}
  	
  	protected List<BusinessObject> loadBusinessObjects(TableModel tableModel) {
  		List<BusinessObject> businessObjects = new ArrayList<BusinessObject>();
  		List<Row> rowList = tableModel.getRowListFull();
  		for (Row row : rowList) {
  			ResultRow resultRow = (ResultRow)row.getObject();
  			if (resultRow.getBusinessObject() != null) {
  				businessObjects.add(resultRow.getBusinessObject());
  			}
  		}
  		return businessObjects;
  	}
  	
  	public BusinessObjectEntry getBusinessObjectEntry() {
  		return businessObjectEntry;
  	}
  	
  	public List<BusinessObject> getBusinessObjects() {
  		return businessObjects;
  	}
  	
  	public boolean attemptCustomExport(OutputStream outputStream, String exportFormat) throws IOException {
  		if (getBusinessObjectEntry() != null && getBusinessObjectEntry().getExporterClass() != null) {
  			Exporter exporter = null;
  			try {
  				exporter = getBusinessObjectEntry().getExporterClass().newInstance();
  			} catch (Exception e) {
  				throw new KualiException("Failed to load export class: " + businessObjectEntry.getExporterClass());
  			}
  			List<String> supportedFormats = exporter.getSupportedFormats(businessObjectEntry.getBusinessObjectClass());
  			if (supportedFormats.contains(exportFormat)) {
  				exporter.export(businessObjectEntry.getBusinessObjectClass(), getBusinessObjects(), exportFormat, outputStream);
  				return true;
 			}
 		}
 		return false;
 	}
 	
 	public boolean attemptCustomExport(Writer writer, String exportFormat) throws IOException {
 		return attemptCustomExport(new WriterOutputStream(writer), exportFormat);
 	}
 	
 }