/*
    * EL4J, the Extension Library for the J2EE, adds incremental enhancements to
    * the spring framework, http://el4j.sf.net
    * Copyright (C) 2005 by ELCA Informatique SA, Av. de la Harpe 22-24,
    * 1000 Lausanne, Switzerland, http://www.elca.ch
    *
    * EL4J is published under the GNU Lesser General Public License (LGPL)
    * Version 2.1. See http://www.gnu.org/licenses/
    *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   * GNU Lesser General Public License for more details.
   *
   * For alternative licensing, please contact info@elca.ch
   */
  
  package ch.elca.el4j.util.codingsupport;
  
  import java.io.File;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.Properties;
  
  import org.springframework.core.io.Resource;
  import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
  
  import ch.elca.el4j.core.io.support.ListResourcePatternResolverDecorator;
  import ch.elca.el4j.core.io.support.ManifestOrderedConfigLocationProvider;
  import ch.elca.el4j.core.io.support.OrderedPathMatchingResourcePatternResolver;
  import ch.elca.el4j.services.monitoring.notification.CoreNotificationHelper;
  
  /**
   * A helper class which handles the loading and storing of Properties to/from
   * files including Spring path resolving.
   *
   * <p>
   * The files can be indicated absolutely or via classpath, i.e. either by
   * "file:C:/folder/..." or by "classpath:folder/...".
   *
   * @svnLink $Revision: 3883 $;$Date: 2009-08-04 15:35:01 +0200 (Di, 04. Aug 2009) $;$Author: swismer $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/core/src/main/java/ch/elca/el4j/util/codingsupport/PropertiesHelper.java $
   *
   * @author Raphael Boog (RBO)
   */
  public class PropertiesHelper {
  	
  	/**
  	 * Loads properties from given resources. Properties declared in late resources overwrite properties.
  	 * declared in earlier resources. Invalid resources just get skipped.
  	 * @param resources    the properties files
  	 * @return             the merged properties
  	 */
  	public static Properties loadPropertiesFromResources(Resource[] resources) {
  		Properties properties = new Properties();
  		InputStream in = null;
  		
  		for (Resource resource : resources) {
  			try {
  				in = resource.getInputStream();
  				properties.load(in);
  			} catch (IOException e) {
  				// ignore
  			} finally {
  				if (in != null) {
  					try {
  						in.close();
  					} catch (IOException e) {
  						CoreNotificationHelper.notifyMisconfiguration(
  							"An IOException was thrown while loading properties from '"
  							+ resource + "'.", e);
  					}
  				}
  			}
  		}
  		
  		return properties;
  	}
  	/**
  	 * Resolves the given file name to an absolute file name and then loads the
  	 * properties from this file to a Properties Object.
  	 *
  	 * @param inputFileName
  	 *            The file(s) which will be loaded
  	 * @return the Properties Object
  	 */
  	public Properties loadProperties(String inputFileName) {
  		// downwards compatibility: append "file:" if it is missing and filename exists
  		String resourceName = inputFileName;
  		if (new File(inputFileName).exists() && !inputFileName.startsWith("file:")) {
  			resourceName = "file:" + resourceName; 
  		}
  
  		ListResourcePatternResolverDecorator resolver = new ListResourcePatternResolverDecorator(
  			new ManifestOrderedConfigLocationProvider(),
  			new OrderedPathMatchingResourcePatternResolver());
  		// most specific resource has to be last, because later properties will overwrite previously set ones.
 		resolver.setMostSpecificResourceLast(true);
 		resolver.setMergeWithOuterResources(true);
 		
 		try {
 			return loadPropertiesFromResources(resolver.getResources(resourceName));
 		} catch (IOException e) {
 			CoreNotificationHelper.notifyMisconfiguration(
 				"An IOException was thrown. The responsible file is '"
 				+ inputFileName + "'.", e);
 			return null;
 		}
 	}
 
 	/**
 	 * Resolves the given file name to an absolute file name and then stores the
 	 * properties from the Properties Object to this file.
 	 *
 	 * @param props
 	 *            The Properties Object
 	 * @param outputFileName
 	 *            The file where the data is stored
 	 */
 	public void storeProperties(Properties props, String outputFileName) {
 
 		PathMatchingResourcePatternResolver pmrpr
 			= new PathMatchingResourcePatternResolver();
 
 		String fileName = null;
 
 		Resource res = pmrpr.getResource(outputFileName);
 		OutputStream out = null;
 		try {
 			try {
 				// Resolve the resource into an absolute file path
 				fileName = res.getURL().getFile();
 			} catch (FileNotFoundException e) {
 				// The file is new
 				File file = new File(outputFileName);
 				fileName = file.getAbsolutePath();
 			}
 			out = new FileOutputStream(fileName);
 			props.store(out, "Title");
 		} catch (FileNotFoundException e) {
 			CoreNotificationHelper.notifyMisconfiguration(
 					"The file '" + outputFileName + "' could not be found.", e);
 		} catch (IOException e) {
 			CoreNotificationHelper.notifyMisconfiguration(
 					"An IOException was thrown. The responsible file is '"
 					+ outputFileName + "'.", e);
 		} finally {
 			if (out != null) {
 				try {
 					out.close();
 				} catch (IOException e) {
 					CoreNotificationHelper.notifyMisconfiguration(
 						"The file '" + outputFileName
 						+ "' could not be close.", e);
 				}
 			}
 		}
 
 	}
 
 }