/*
    * Copyright 2006-2012 smartics, Kronseder & Reiner GmbH
    *
    * Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
    *
   * 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 de.smartics.maven.plugin.buildmetadata.io;
  
  import java.io.BufferedOutputStream;
  import java.io.File;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.util.List;
  import java.util.Properties;
  
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  import javax.xml.parsers.ParserConfigurationException;
  import javax.xml.transform.TransformerException;
  
  import org.apache.commons.io.IOUtils;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugin.logging.Log;
  import org.w3c.dom.Document;
  
  import de.smartics.maven.io.MojoIoUtils;
  import de.smartics.maven.plugin.buildmetadata.common.MojoUtils;
  import de.smartics.maven.plugin.buildmetadata.common.Property;
  
  /**
   * Helper to handle the build meta data properties file.
   *
   * @author <a href="mailto:robert.reiner@smartics.de">Robert Reiner</a>
   * @version $Revision:591 $
   */
  public final class BuildXmlFileHelper
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    /**
     * The logger to use.
     */
    private final Log log;
  
    /**
     * The file to write to.
     */
    private final File xmlOutputFile;
  
    /**
     * The list of a system properties or environment variables to be selected by
     * the user to include into the build meta data properties.
     * <p>
     * The name is the name of the property, the section is relevant for placing
     * the property in one of the following sections:
     * </p>
     * <ul>
     * <li><code>build.scm</code></li>
     * <li><code>build.dateAndVersion</code></li>
     * <li><code>build.runtime</code></li>
     * <li><code>build.java</code></li>
     * <li><code>build.maven</code></li>
     * <li><code>build.misc</code></li>
     * </ul>
     * <p>
     * If no valid section is given, the property is silently rendered in the
     * <code>build.misc</code> section.
     * </p>
     */
    private final List<Property> selectedProperties;
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     *
     * @param log the logger to use.
     * @param xmlOutputFile the file to write to.
     * @param selectedProperties the list of a system properties or environment
     *          variables to be selected by the user to include into the build
     *          meta data properties.
     */
   public BuildXmlFileHelper(final Log log, final File xmlOutputFile,
       final List<Property> selectedProperties)
   {
     this.log = log;
     this.xmlOutputFile = xmlOutputFile;
     this.selectedProperties = selectedProperties;
   }
 
   // ****************************** Inner Classes *****************************
 
   // ********************************* Methods ********************************
 
   // --- init -----------------------------------------------------------------
 
   // --- get&set --------------------------------------------------------------
 
   // --- business -------------------------------------------------------------
 
   /**
    * Writes the build meta data XML file to the target file.
    *
    * @param buildMetaDataProperties the properties to write.
    * @return the reference to the written file.
    * @throws MojoExecutionException on any problem encountered while writing the
    *           XML file.
    */
   public File writeXmlFile(final Properties buildMetaDataProperties)
     throws MojoExecutionException
   {
     final File buildMetaDataFile = createBuildMetaDataFile(xmlOutputFile);
     if (log.isInfoEnabled())
     {
       log.info("Writing XML report '" + buildMetaDataFile.getAbsolutePath()
                + "'...");
     }
 
     writeContent(buildMetaDataProperties, buildMetaDataFile);
 
     return buildMetaDataFile;
   }
 
   private void writeContent(final Properties buildMetaDataProperties,
       final File buildMetaDataFile) throws MojoExecutionException
   {
     OutputStream out = null;
     try
     {
       out = new BufferedOutputStream(new FileOutputStream(buildMetaDataFile));
       serializeDocument(buildMetaDataProperties, out);
     }
     catch (final FileNotFoundException e)
     {
       final String message =
           "Cannot find file '" + buildMetaDataFile
               + "' to write XML report to.";
       throw MojoUtils.createException(log, e, message);
     }
     catch (final IOException e)
     {
       final String message =
           "Cannot write XML report to file '" + buildMetaDataFile + "'.";
       throw MojoUtils.createException(log, e, message);
     }
     catch (final ParserConfigurationException e)
     {
       final String message =
           "Cannot create XML report to write to file '" + buildMetaDataFile
               + "'.";
       throw MojoUtils.createException(log, e, message);
     }
     catch (final TransformerException e)
     {
       final String message =
           "Cannot transform build meta data to XML to write to file '"
               + buildMetaDataFile + "'.";
       throw MojoUtils.createException(log, e, message);
     }
     finally
     {
       IOUtils.closeQuietly(out);
     }
   }
 
   private void serializeDocument(final Properties buildMetaDataProperties,
       final OutputStream out) throws ParserConfigurationException, IOException,
     TransformerException
   {
     final Document document = createDocument();
     final SdocBuilder builder =
         new SdocBuilder(document, buildMetaDataProperties, selectedProperties);
     builder.writeDocumentContent();
     MojoIoUtils.serialize(document, out);
   }
 
   /**
    * Creates the properties file for the build meta data. If the directory to
    * place it in is not present, it will be created.
    *
    * @return the file to write the build properties to.
    * @throws MojoExecutionException if the output directory is not present and
    *           cannot be created.
    */
   private File createBuildMetaDataFile(final File propertiesOutputFile)
     throws MojoExecutionException
   {
     final File outputDirectory = propertiesOutputFile.getParentFile();
     if (!outputDirectory.exists())
     {
       final boolean created = outputDirectory.mkdirs();
       if (!created)
       {
         throw new MojoExecutionException("Cannot create output directory '"
                                          + outputDirectory + "'.");
       }
     }
     return propertiesOutputFile;
   }
 
   private Document createDocument() throws ParserConfigurationException
   {
     final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
     final DocumentBuilder builder = factory.newDocumentBuilder();
     final Document document = builder.newDocument();
     return document;
   }
 
   // --- object basics --------------------------------------------------------
 
 }