//
   //  ========================================================================
   //  Copyright (c) 1995-2012 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.plugins.util;
  
  import java.io.File;
  import java.io.FileReader;
  import java.io.IOException;
  
  import org.xml.sax.Attributes;
  import org.xml.sax.ContentHandler;
  import org.xml.sax.InputSource;
  import org.xml.sax.Locator;
  import org.xml.sax.SAXException;
  import org.xml.sax.XMLReader;
  import org.xml.sax.helpers.XMLReaderFactory;
  
  public class MavenUtils
  {
      private final static String DEFAULT_REPOSITORY_LOCATION = System.getProperty("user.home") + "/.m2/repository/";
  
      /**
       * Looks for maven's settings.xml in $M2_HOME/conf/settings.xml
       *
       * @return a file representing the global settings.xml
       */
      static File findGlobalSettingsXml()
      {
          String m2Home = System.getenv("M2_HOME");
          return new File(m2Home + "/conf/settings.xml");
      }
  
      /**
       * Looks for maven's settings.xml in ${user.home}/.m2/settings.xml
       *
       * @return a file representing the user's settings.xml
       */
      static File findUserSettingsXml()
      {
          String userHome = System.getProperty("user.home");
          return new File(userHome + "/.m2/settings.xml");
      }
  
      /**
       * Read the local repository location from settings.xml. A setting in the user's settings.xml will override the
       * global one.
       *
       * @return location of the local maven repo
       */
      public static String getLocalRepositoryLocation()
      {
          String repositoryLocation = DEFAULT_REPOSITORY_LOCATION;
          try
          {
              // find the global setting
              String tempRepositoryLocation = parseSettingsXml(findGlobalSettingsXml());
              if (tempRepositoryLocation != null)
                  repositoryLocation = tempRepositoryLocation;
  
              // override with user settings.xml
              tempRepositoryLocation = parseSettingsXml(findUserSettingsXml());
              if (tempRepositoryLocation != null)
                  repositoryLocation = tempRepositoryLocation;
          }
          catch (IOException | SAXException e)
          {
              throw new IllegalStateException(e);
          }
          return repositoryLocation;
      }
  
      private static String parseSettingsXml(File settingsXml) throws IOException, SAXException
      {
          if(!settingsXml.exists())
              return null;
  
          // readability is more important than efficiency here, so we just recreate those objects
          XMLReader reader = XMLReaderFactory.createXMLReader();
          SettingsXmlContentHandler settingsXmlContentHandler = new SettingsXmlContentHandler();
          reader.setContentHandler(settingsXmlContentHandler);
  
          InputSource source = new InputSource(new FileReader(settingsXml));
          reader.parse(source);
          return settingsXmlContentHandler.getRepositoryLocation();
     }
 
     private static class SettingsXmlContentHandler implements ContentHandler
     {
         private String repositoryLocation;
         private String currentValue;
 
         @Override
         public void characters(char[] ch, int start, int length) throws SAXException
         {
             currentValue = new String(ch, start, length);
         }
 
         @Override
         public void endElement(String uri, String localName, String qName) throws SAXException
         {
             if (localName.equals("localRepository"))
             {
                 repositoryLocation = currentValue;
             }
         }
 
         public String getRepositoryLocation()
         {
             return repositoryLocation;
         }
 
         @Override
         public void setDocumentLocator(Locator locator)
         {
         }
 
         @Override
         public void startDocument() throws SAXException
         {
         }
 
         @Override
         public void endDocument() throws SAXException
         {
         }
 
         @Override
         public void startPrefixMapping(String prefix, String uri) throws SAXException
         {
         }
 
         @Override
         public void endPrefixMapping(String prefix) throws SAXException
         {
         }
 
         @Override
         public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException
         {
         }
 
         @Override
         public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException
         {
         }
 
         @Override
         public void processingInstruction(String target, String data) throws SAXException
         {
         }
 
         @Override
         public void skippedEntity(String name) throws SAXException
         {
         }
     }
 }