package org.codehaus.mojo.jaxb2.schemageneration;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugin.logging.Log;
  import org.codehaus.mojo.jaxb2.schemageneration.postprocessing.NodeProcessor;
  import org.codehaus.mojo.jaxb2.schemageneration.postprocessing.javadoc.JavaDocRenderer;
  import org.codehaus.mojo.jaxb2.schemageneration.postprocessing.javadoc.SearchableDocumentation;
  import org.codehaus.mojo.jaxb2.schemageneration.postprocessing.javadoc.XsdAnnotationProcessor;
  import org.codehaus.mojo.jaxb2.schemageneration.postprocessing.schemaenhancement.ChangeFilenameProcessor;
  import org.codehaus.mojo.jaxb2.schemageneration.postprocessing.schemaenhancement.ChangeNamespacePrefixProcessor;
  import org.codehaus.mojo.jaxb2.schemageneration.postprocessing.schemaenhancement.SimpleNamespaceResolver;
  import org.codehaus.mojo.jaxb2.schemageneration.postprocessing.schemaenhancement.TransformSchema;
  import org.codehaus.mojo.jaxb2.shared.FileSystemUtilities;
  import org.codehaus.mojo.jaxb2.shared.Validate;
  import org.codehaus.plexus.util.FileUtils;
  import org.codehaus.plexus.util.IOUtil;
  import org.codehaus.plexus.util.StringUtils;
  import org.w3c.dom.Document;
  import org.w3c.dom.NamedNodeMap;
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  import org.xml.sax.InputSource;
  
  import javax.xml.parsers.DocumentBuilderFactory;
  import javax.xml.transform.OutputKeys;
  import javax.xml.transform.Transformer;
  import javax.xml.transform.TransformerException;
  import javax.xml.transform.TransformerFactory;
  import javax.xml.transform.dom.DOMSource;
  import javax.xml.transform.stream.StreamResult;
  import java.io.BufferedWriter;
  import java.io.File;
  import java.io.FileFilter;
  import java.io.FileNotFoundException;
  import java.io.FileReader;
  import java.io.FileWriter;
  import java.io.IOException;
  import java.io.Reader;
  import java.io.StringWriter;
  import java.io.Writer;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  
  /**
   * Utility class holding algorithms used when generating XSD schema.
   *
   * @author <a href="mailto:lj@jguru.se">Lennart J&ouml;relid</a>
   * @since 1.4
   */
  public final class XsdGeneratorHelper {
  
      // Constants
      private static final String MISCONFIG = "Misconfiguration detected: ";
      private static TransformerFactory FACTORY;
      private static final FileFilter RECURSIVE_XSD_FILTER;
  
      /**
       * Hide the constructor for utility classes.
       */
      private XsdGeneratorHelper() {
          // Do nothing.
      }
  
      static {
  
          // Create the static filter used for recursive generated XSD files detection.
          RECURSIVE_XSD_FILTER = new FileFilter() {
              @Override
              public boolean accept(final File toMatch) {
  
                  if (toMatch.exists()) {
  
                      // Accept directories for recursive operation, and
                      // files with names matching the SCHEMAGEN_EMITTED_FILENAME Pattern.
                      return toMatch.isDirectory()
                              || AbstractXsdGeneratorMojo.SCHEMAGEN_EMITTED_FILENAME.matcher(toMatch.getName()).matches();
                  }
  
                 // Not a directory or XSD file.
                 return false;
             }
         };
     }
 
     /**
      * Acquires a map relating generated schema filename to its SimpleNamespaceResolver.
      *
      * @param outputDirectory The output directory of the generated schema files.
      * @return a map relating generated schema filename to an initialized SimpleNamespaceResolver.
      * @throws MojoExecutionException if two generated schema files used the same namespace URI.
      */
     public static Map<String, SimpleNamespaceResolver> getFileNameToResolverMap(final File outputDirectory)
             throws MojoExecutionException {
 
         final Map<String, SimpleNamespaceResolver> toReturn = new TreeMap<String, SimpleNamespaceResolver>();
 
         // Each generated schema file should be written to the output directory.
         // Each generated schema file should have a unique targetNamespace.
         File[] generatedSchemaFiles = outputDirectory.listFiles(new FileFilter() {
             public boolean accept(File pathname) {
                 return pathname.getName().startsWith("schema") && pathname.getName().endsWith(".xsd");
             }
         });
 
         for (File current : generatedSchemaFiles) {
             toReturn.put(current.getName(), new SimpleNamespaceResolver(current));
         }
 
         return toReturn;
     }
 
     /**
      * Validates that the list of Schemas provided within the configuration all contain unique values. Should a
      * MojoExecutionException be thrown, it contains informative text about the exact nature of the configuration
      * problem - we should simplify for all plugin users.
      *
      * @param configuredTransformSchemas The List of configuration schemas provided to this mojo.
      * @throws MojoExecutionException if any two configuredSchemas instances contain duplicate values for any of the
      *                                properties uri, prefix or file. Also throws a MojoExecutionException if the uri of any Schema is null
      *                                or empty, or if none of the 'file' and 'prefix' properties are given within any of the
      *                                configuredSchema instances.
      */
     public static void validateSchemasInPluginConfiguration(final List<TransformSchema> configuredTransformSchemas)
             throws MojoExecutionException {
         final List<String> uris = new ArrayList<String>();
         final List<String> prefixes = new ArrayList<String>();
         final List<String> fileNames = new ArrayList<String>();
 
         for (int i = 0; i < configuredTransformSchemas.size(); i++) {
             final TransformSchema current = configuredTransformSchemas.get(i);
             final String currentURI = current.getUri();
             final String currentPrefix = current.getToPrefix();
             final String currentFile = current.getToFile();
 
             // We cannot work with a null or empty uri
             if (StringUtils.isEmpty(currentURI)) {
                 throw new MojoExecutionException(MISCONFIG + "Null or empty property 'uri' found in "
                         + "plugin configuration for schema element at index [" + i + "]: " + current);
             }
 
             // No point in having *only* a namespace.
             if (StringUtils.isEmpty(currentPrefix) && StringUtils.isEmpty(currentFile)) {
                 throw new MojoExecutionException(MISCONFIG + "Null or empty properties 'prefix' "
                         + "and 'file' found within plugin configuration for schema element at index ["
                         + i + "]: " + current);
             }
 
             // Validate that all given uris are unique.
             if (uris.contains(currentURI)) {
                 throw new MojoExecutionException(getDuplicationErrorMessage("uri", currentURI,
                         uris.indexOf(currentURI), i));
             }
             uris.add(currentURI);
 
             // Validate that all given prefixes are unique.
             if (prefixes.contains(currentPrefix) && !(currentPrefix == null)) {
                 throw new MojoExecutionException(getDuplicationErrorMessage("prefix", currentPrefix,
                         prefixes.indexOf(currentPrefix), i));
             }
             prefixes.add(currentPrefix);
 
             // Validate that all given files are unique.
             if (fileNames.contains(currentFile)) {
                 throw new MojoExecutionException(getDuplicationErrorMessage("file", currentFile,
                         fileNames.indexOf(currentFile), i));
             }
             fileNames.add(currentFile);
         }
     }
 
     /**
      * Inserts XML documentation annotations into all generated XSD files found within the
      * supplied outputDir.
      *
      * @param log       A Maven Log.
      * @param outputDir The outputDir, where generated XSD files are found.
      * @param docs      The SearchableDocumentation for the source files within the compilation unit.
      * @param renderer  The JavaDocRenderer used to convert JavaDoc annotations into XML documentation annotations.
      * @return The number of processed XSDs.
      */
     public static int insertJavaDocAsAnnotations(final Log log,
                                                  final File outputDir,
                                                  final SearchableDocumentation docs,
                                                  final JavaDocRenderer renderer) {
 
         // Check sanity
         Validate.notNull(docs, "docs");
         Validate.notNull(log, "log");
         Validate.notNull(outputDir, "outputDir");
         Validate.isTrue(outputDir.isDirectory(), "'outputDir' must be a Directory.");
         Validate.notNull(renderer, "renderer");
 
         int processedXSDs = 0;
         final List<File> foundFiles = new ArrayList<File>();
         addRecursively(foundFiles, RECURSIVE_XSD_FILTER, outputDir);
 
         if (foundFiles.size() > 0) {
 
             // Create the processor.
             final XsdAnnotationProcessor processor = new XsdAnnotationProcessor(docs, renderer);
 
             for (File current : foundFiles) {
 
                 // Create an XSD document from the current File.
                 final Document generatedSchemaFileDocument = parseXmlToDocument(current);
 
                 // Replace all namespace prefixes within the provided document.
                 process(generatedSchemaFileDocument.getFirstChild(), true, processor);
                 processedXSDs++;
 
                 // Overwrite the vanilla file.
                 savePrettyPrintedDocument(generatedSchemaFileDocument, current);
             }
 
         } else {
             if (log.isWarnEnabled()) {
                 log.warn("Found no generated 'vanilla' XSD files to process under ["
                         + FileSystemUtilities.getCanonicalPath(outputDir) + "]. Aborting processing.");
             }
         }
 
         // All done.
         return processedXSDs;
     }
 
     /**
      * Replaces all namespaces within generated schema files, as instructed by the configured Schema instances.
      *
      * @param resolverMap                The map relating generated schema file name to SimpleNamespaceResolver instances.
      * @param configuredTransformSchemas The Schema instances read from the configuration of this plugin.
      * @param mavenLog                   The active Log.
      * @param schemaDirectory            The directory where all generated schema files reside.
      * @throws MojoExecutionException If the namespace replacement could not be done.
      */
     public static void replaceNamespacePrefixes(final Map<String, SimpleNamespaceResolver> resolverMap,
                                                 final List<TransformSchema> configuredTransformSchemas,
                                                 final Log mavenLog,
                                                 final File schemaDirectory)
             throws MojoExecutionException {
 
         if (mavenLog.isDebugEnabled()) {
             mavenLog.debug("Got resolverMap.keySet() [generated filenames]: " + resolverMap.keySet());
         }
 
         for (SimpleNamespaceResolver currentResolver : resolverMap.values()) {
             File generatedSchemaFile = new File(schemaDirectory, currentResolver.getSourceFilename());
             Document generatedSchemaFileDocument = null;
 
             for (TransformSchema currentTransformSchema : configuredTransformSchemas) {
                 // Should we alter the namespace prefix as instructed by the current schema?
                 final String newPrefix = currentTransformSchema.getToPrefix();
                 final String currentUri = currentTransformSchema.getUri();
 
                 if (StringUtils.isNotEmpty(newPrefix)) {
                     // Find the old/current prefix of the namespace for the current schema uri.
                     final String oldPrefix = currentResolver.getNamespaceURI2PrefixMap().get(currentUri);
 
                     if (StringUtils.isNotEmpty(oldPrefix)) {
                         // Can we perform the prefix substitution?
                         validatePrefixSubstitutionIsPossible(oldPrefix, newPrefix, currentResolver);
 
                         if (mavenLog.isDebugEnabled()) {
                             mavenLog.debug("Subtituting namespace prefix [" + oldPrefix + "] with [" + newPrefix
                                     + "] in file [" + currentResolver.getSourceFilename() + "].");
                         }
 
                         // Get the Document of the current schema file.
                         if (generatedSchemaFileDocument == null) {
                             generatedSchemaFileDocument = parseXmlToDocument(generatedSchemaFile);
                         }
 
                         // Replace all namespace prefixes within the provided document.
                         process(generatedSchemaFileDocument.getFirstChild(), true,
                                 new ChangeNamespacePrefixProcessor(oldPrefix, newPrefix));
                     }
                 }
             }
 
             if (generatedSchemaFileDocument != null) {
                 // Overwrite the generatedSchemaFile with the content of the generatedSchemaFileDocument.
                 mavenLog.debug("Overwriting file [" + currentResolver.getSourceFilename() + "] with content ["
                         + getHumanReadableXml(generatedSchemaFileDocument) + "]");
                 savePrettyPrintedDocument(generatedSchemaFileDocument, generatedSchemaFile);
             } else {
                 mavenLog.debug("No namespace prefix changes to generated schema file ["
                         + generatedSchemaFile.getName() + "]");
             }
         }
     }
 
     /**
      * Updates all schemaLocation attributes within the generated schema files to match the 'file' properties within the
      * Schemas read from the plugin configuration. After that, the files are physically renamed.
      *
      * @param resolverMap                The map relating generated schema file name to SimpleNamespaceResolver instances.
      * @param configuredTransformSchemas The Schema instances read from the configuration of this plugin.
      * @param mavenLog                   The active Log.
      * @param schemaDirectory            The directory where all generated schema files reside.
      */
     public static void renameGeneratedSchemaFiles(final Map<String, SimpleNamespaceResolver> resolverMap,
                                                   final List<TransformSchema> configuredTransformSchemas,
                                                   final Log mavenLog, final File schemaDirectory) {
         // Create the map relating namespace URI to desired filenames.
         Map<String, String> namespaceUriToDesiredFilenameMap = new TreeMap<String, String>();
         for (TransformSchema current : configuredTransformSchemas) {
             if (StringUtils.isNotEmpty(current.getToFile())) {
                 namespaceUriToDesiredFilenameMap.put(current.getUri(), current.getToFile());
             }
         }
 
         // Replace the schemaLocation values to correspond to the new filenames
         for (SimpleNamespaceResolver currentResolver : resolverMap.values()) {
             File generatedSchemaFile = new File(schemaDirectory, currentResolver.getSourceFilename());
             Document generatedSchemaFileDocument = parseXmlToDocument(generatedSchemaFile);
 
             // Replace all namespace prefixes within the provided document.
             process(generatedSchemaFileDocument.getFirstChild(), true,
                     new ChangeFilenameProcessor(namespaceUriToDesiredFilenameMap));
 
             // Overwrite the generatedSchemaFile with the content of the generatedSchemaFileDocument.
             if (mavenLog.isDebugEnabled()) {
                 mavenLog.debug("Changed schemaLocation entries within [" + currentResolver.getSourceFilename() + "]. "
                         + "Result: [" + getHumanReadableXml(generatedSchemaFileDocument) + "]");
             }
             savePrettyPrintedDocument(generatedSchemaFileDocument, generatedSchemaFile);
         }
 
         // Now, rename the actual files.
         for (SimpleNamespaceResolver currentResolver : resolverMap.values()) {
             final String localNamespaceURI = currentResolver.getLocalNamespaceURI();
 
             if (StringUtils.isEmpty(localNamespaceURI)) {
                 mavenLog.warn("SimpleNamespaceResolver contained no localNamespaceURI; aborting rename.");
                 continue;
             }
 
             final String newFilename = namespaceUriToDesiredFilenameMap.get(localNamespaceURI);
             final File originalFile = new File(schemaDirectory, currentResolver.getSourceFilename());
 
             if (StringUtils.isNotEmpty(newFilename)) {
                 File renamedFile = FileUtils.resolveFile(schemaDirectory, newFilename);
                 String renameResult = (originalFile.renameTo(renamedFile) ? "Success " : "Failure ");
 
                 if (mavenLog.isDebugEnabled()) {
                     String suffix = "renaming [" + originalFile.getAbsolutePath() + "] to [" + renamedFile + "]";
                     mavenLog.debug(renameResult + suffix);
                 }
             }
         }
     }
 
     /**
      * Drives the supplied visitor to process the provided Node and all its children, should the recurseToChildren flag
      * be set to <code>true</code>. All attributes of the current node are processed before recursing to children (i.e.
      * breadth first recursion).
      *
      * @param node              The Node to process.
      * @param recurseToChildren if <code>true</code>, processes all children of the supplied node recursively.
      * @param visitor           The NodeProcessor instance which should process the nodes.
      */
     public static void process(final Node node, final boolean recurseToChildren, final NodeProcessor visitor) {
         // Process the current Node, if the NodeProcessor accepts it.
         if (visitor.accept(node)) {
             visitor.process(node);
         }
 
         NamedNodeMap attributes = node.getAttributes();
         for (int i = 0; i < attributes.getLength(); i++) {
             Node attribute = attributes.item(i);
 
             // Process the current attribute, if the NodeProcessor accepts it.
             if (visitor.accept(attribute)) {
                 visitor.process(attribute);
             }
         }
 
         if (recurseToChildren) {
             NodeList children = node.getChildNodes();
             for (int i = 0; i < children.getLength(); i++) {
                 Node child = children.item(i);
 
                 // Recurse to Element children.
                 if (child.getNodeType() == Node.ELEMENT_NODE) {
                     process(child, true, visitor);
                 }
             }
         }
     }
 
     /**
      * Parses the provided InputStream to create a dom Document.
      *
      * @param xmlStream An InputStream connected to an XML document.
      * @return A DOM Document created from the contents of the provided stream.
      */
     public static Document parseXmlStream(final Reader xmlStream) {
 
         // Build a DOM model of the provided xmlFileStream.
         final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
         factory.setNamespaceAware(true);
 
         try {
             return factory.newDocumentBuilder().parse(new InputSource(xmlStream));
         } catch (Exception e) {
             throw new IllegalArgumentException("Could not acquire DOM Document", e);
         }
     }
 
     /**
      * Converts the provided DOM Node to a pretty-printed XML-formatted string.
      *
      * @param node The Node whose children should be converted to a String.
      * @return a pretty-printed XML-formatted string.
      */
     protected static String getHumanReadableXml(final Node node) {
         StringWriter toReturn = new StringWriter();
 
         try {
             Transformer transformer = getFactory().newTransformer();
             transformer.setOutputProperty(OutputKeys.INDENT, "yes");
             transformer.setOutputProperty(OutputKeys.STANDALONE, "yes");
             transformer.transform(new DOMSource(node), new StreamResult(toReturn));
         } catch (TransformerException e) {
             throw new IllegalStateException("Could not transform node [" + node.getNodeName() + "] to XML", e);
         }
 
         return toReturn.toString();
     }
 
     //
     // Private helpers
     //
 
     private static String getDuplicationErrorMessage(final String propertyName, final String propertyValue,
                                                      final int firstIndex, final int currentIndex) {
         return MISCONFIG + "Duplicate '" + propertyName + "' property with value [" + propertyValue
                 + "] found in plugin configuration. Correct schema elements index (" + firstIndex + ") and ("
                 + currentIndex + "), to ensure that all '" + propertyName + "' values are unique.";
     }
 
     /**
      * Validates that the transformation from <code>oldPrefix</code> to <code>newPrefix</code> is possible, in that
      * <code>newPrefix</code> is not already used by a schema file. This would corrupt the schema by assigning elements
      * from one namespace to another.
      *
      * @param oldPrefix       The old/current namespace prefix.
      * @param newPrefix       The new/future namespace prefix.
      * @param currentResolver The currently active SimpleNamespaceResolver.
      * @throws MojoExecutionException if any schema file currently uses <code>newPrefix</code>.
      */
     private static void validatePrefixSubstitutionIsPossible(final String oldPrefix, final String newPrefix,
                                                              final SimpleNamespaceResolver currentResolver)
             throws MojoExecutionException {
         // Make certain the newPrefix does not exist already.
         if (currentResolver.getNamespaceURI2PrefixMap().containsValue(newPrefix)) {
             throw new MojoExecutionException(MISCONFIG + "Namespace prefix [" + newPrefix + "] is already in use."
                     + " Cannot replace namespace prefix [" + oldPrefix + "] with [" + newPrefix + "] in file ["
                     + currentResolver.getSourceFilename() + "].");
         }
     }
 
     /**
      * Creates a Document from parsing the XML within the provided xmlFile.
      *
      * @param xmlFile The XML file to be parsed.
      * @return The Document corresponding to the xmlFile.
      */
     private static Document parseXmlToDocument(final File xmlFile) {
         Document result = null;
         Reader reader = null;
         try {
             reader = new FileReader(xmlFile);
             result = parseXmlStream(reader);
         } catch (FileNotFoundException e) {
             // This should never happen...
         } finally {
             IOUtil.close(reader);
         }
 
         return result;
     }
 
     private static void savePrettyPrintedDocument(final Document toSave, final File targetFile) {
         Writer out = null;
         try {
             out = new BufferedWriter(new FileWriter(targetFile));
             out.write(getHumanReadableXml(toSave.getFirstChild()));
         } catch (IOException e) {
             throw new IllegalStateException("Could not write to file [" + targetFile.getAbsolutePath() + "]", e);
         } finally {
             IOUtil.close(out);
         }
     }
 
     private static void addRecursively(final List<File> toPopulate,
                                        final FileFilter fileFilter,
                                        final File aDir) {
 
         // Check sanity
         Validate.notNull(toPopulate, "toPopulate");
         Validate.notNull(fileFilter, "fileFilter");
         Validate.notNull(aDir, "aDir");
 
         // Add all matching files.
         for (File current : aDir.listFiles(fileFilter)) {
 
             if (current.isFile()) {
                 toPopulate.add(current);
             } else if (current.isDirectory()) {
                 addRecursively(toPopulate, fileFilter, current);
             }
         }
     }
 
     private static TransformerFactory getFactory() {
 
         if(FACTORY == null) {
 
             try {
                 FACTORY = TransformerFactory.newInstance();
 
                 // Harmonize XML formatting
                 FACTORY.setAttribute("indent-number", 2);
 
             } catch (Throwable exception) {
 
                 // This should really not happen... but it seems to happen in some test cases.
                 throw new IllegalStateException("Could not acquire TransformerFactory implementation.", exception);
             }
         }
 
         // All done.
         return FACTORY;
     }
 }