// ========================================================================
   // Copyright (c) 2009 Intalio, Inc.
   // ------------------------------------------------------------------------
   // 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.osgi.boot.internal.webapp;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.eclipse.jetty.osgi.boot.JettyBootstrapActivator;
  import org.eclipse.jetty.osgi.boot.OSGiServerConstants;
  import org.eclipse.jetty.osgi.boot.OSGiWebappConstants;
  import org.eclipse.jetty.osgi.boot.internal.serverfactory.DefaultJettyAtJettyHomeHelper;
  import org.eclipse.jetty.osgi.boot.internal.serverfactory.IManagedJettyServerRegistry;
  import org.eclipse.jetty.osgi.boot.internal.serverfactory.ServerInstanceWrapper;
  import org.eclipse.jetty.server.handler.ContextHandler;
  import org.eclipse.jetty.util.Scanner;
  import org.eclipse.jetty.webapp.WebAppContext;
  import org.osgi.framework.Bundle;
  import org.osgi.framework.BundleContext;
  import org.osgi.framework.FrameworkUtil;
  import org.osgi.framework.ServiceEvent;
  import org.osgi.framework.ServiceListener;
  import org.osgi.framework.ServiceReference;
  
  /**
   * When a {@link ContextHandler} service is activated we look into it and if the
   * corresponding webapp is actually not configured then we go and register it.
   * <p>
   * The idea is to always go through this class when we deploy a new webapp on
   * jetty.
   * </p>
   * <p>
   * We are exposing each web-application as an OSGi service. This lets us update
   * the webapps and stop/start them directly at the OSGi layer. It also give us
   * many ways to declare those services: Declarative Services for example. <br/>
   * It is a bit different from the way the HttpService works where we would have
   * a WebappService and we woud register a webapp onto it. <br/>
   * It does not go against RFC-66 nor does it prevent us from supporting the
   * WebappContainer semantics.
   * </p>
   */
  public class JettyContextHandlerServiceTracker implements ServiceListener
  {
  
  	/** New style: ability to manage multiple jetty instances */
  	private final IManagedJettyServerRegistry _registry;
  
      /** The context-handler to deactivate indexed by context handler */
      private Map<ServiceReference, ContextHandler> _indexByServiceReference = new HashMap<ServiceReference, ContextHandler>();
  
      /**
       * The index is the bundle-symbolic-name/path/to/context/file when there is such thing
       */
      private Map<String, ServiceReference> _indexByContextFile = new HashMap<String, ServiceReference>();
  
      /** in charge of detecting changes in the osgi contexts home folder. */
      private Scanner _scanner;
  
      /**
       * @param registry
       */
      public JettyContextHandlerServiceTracker(IManagedJettyServerRegistry registry) throws Exception
      {
      	_registry = registry;
      }
  
      public void stop() throws Exception
      {
          if (_scanner != null)
          {
              _scanner.stop();
          }
          // the class that created the server is also in charge of stopping it.
          // nothing to stop in the WebappRegistrationHelper
  
      }
      
      /**
       * @param contextHome Parent folder where the context files can override the context files
       * defined in the web bundles: equivalent to the contexts folder in a traditional
       * jetty installation.
       * when null, just do nothing.
       */
      protected void setupContextHomeScanner(File contextHome) throws IOException
      {
          if (contextHome == null)
          {
          	return;
         }
         final String osgiContextHomeFolderCanonicalPath = contextHome.getCanonicalPath();
         _scanner = new Scanner();
         _scanner.setRecursive(true);
         _scanner.setReportExistingFilesOnStartup(false);
         _scanner.addListener(new Scanner.DiscreteListener()
         {
             public void fileAdded(String filename) throws Exception
             {
                 // adding a file does not create a new app,
                 // it just reloads it with the new custom file.
                 // well, if the file does not define a context handler,
                 // then in fact it does remove it.
                 reloadJettyContextHandler(filename, osgiContextHomeFolderCanonicalPath);
             }
 
             public void fileChanged(String filename) throws Exception
             {
                 reloadJettyContextHandler(filename, osgiContextHomeFolderCanonicalPath);
             }
 
             public void fileRemoved(String filename) throws Exception
             {
                 // removing a file does not remove the app:
                 // it just goes back to the default embedded in the bundle.
                 // well, if there was no default then it does remove it.
                 reloadJettyContextHandler(filename, osgiContextHomeFolderCanonicalPath);
             }
         });
 
     }
 
     /**
      * Receives notification that a service has had a lifecycle change.
      * 
      * @param ev
      *            The <code>ServiceEvent</code> object.
      */
     public void serviceChanged(ServiceEvent ev)
     {
         ServiceReference sr = ev.getServiceReference();
         switch (ev.getType())
         {
             case ServiceEvent.MODIFIED:
             case ServiceEvent.UNREGISTERING:
             {
                 ContextHandler ctxtHandler = unregisterInIndex(ev.getServiceReference());
                 if (ctxtHandler != null && !ctxtHandler.isStopped())
                 {
                     try
                     {
                     	getWebBundleDeployerHelp(sr).unregister(ctxtHandler);
                     }
                     catch (Exception e)
                     {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
                     }
                 }
             }
             if (ev.getType() == ServiceEvent.UNREGISTERING)
             {
                 break;
             }
             else
             {
                 // modified, meaning: we reload it. now that we stopped it;
                 // we can register it.
             }
             case ServiceEvent.REGISTERED:
             {
                 Bundle contributor = sr.getBundle();
                 BundleContext context = FrameworkUtil.getBundle(JettyBootstrapActivator.class).getBundleContext();
                 ContextHandler contextHandler = (ContextHandler)context.getService(sr);
                 if (contextHandler.getServer() != null)
                 {
                     // is configured elsewhere.
                     return;
                 }
                 String contextFilePath = (String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_CONTEXT_FILE_PATH);
                 if (contextHandler instanceof WebAppContext && contextFilePath == null)
                 //it could be a web-application that will in fact be configured via a context file.
                 //that case is identified by the fact that the contextFilePath is not null
                 //in that case we must use the register context methods.
                 {
                     WebAppContext webapp = (WebAppContext)contextHandler;
                     String contextPath = (String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_CONTEXT_PATH);
                     if (contextPath == null)
                     {
                         contextPath = webapp.getContextPath();
                     }
                     String webXmlPath = (String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_WEB_XML_PATH);
                     if (webXmlPath == null)
                     {
                         webXmlPath = webapp.getDescriptor();
                     }
                     String defaultWebXmlPath = (String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_DEFAULT_WEB_XML_PATH);
                     if (defaultWebXmlPath == null)
                     {
                         String jettyHome = System.getProperty(DefaultJettyAtJettyHomeHelper.SYS_PROP_JETTY_HOME);
                         if (jettyHome != null)
                         {
                             File etc = new File(jettyHome, "etc");
                             if (etc.exists() && etc.isDirectory())
                             {
                                 File webDefault = new File (etc, "webdefault.xml");
                                 if (webDefault.exists())
                                     defaultWebXmlPath = webDefault.getAbsolutePath();
                                 else
                                     defaultWebXmlPath = webapp.getDefaultsDescriptor();
                             }
                             else
                                 defaultWebXmlPath = webapp.getDefaultsDescriptor();
                         }
                     }
                     String war = (String)sr.getProperty("war");
                     try
                     {
                     	IWebBundleDeployerHelper deployerHelper = getWebBundleDeployerHelp(sr);
                     	if (deployerHelper == null)
                     	{
                     		
                     	}
                     	else
                     	{
                     		WebAppContext handler = deployerHelper
                         		.registerWebapplication(contributor,war,contextPath,
                         		(String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_EXTRA_CLASSPATH),
                         		(String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_BUNDLE_INSTALL_LOCATION_OVERRIDE),
                         		(String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_REQUIRE_TLD_BUNDLE),
                                 webXmlPath,defaultWebXmlPath,webapp);
                             if (handler != null)
                             {
                                 registerInIndex(handler,sr);
                             }
                     	}
                     }
                     catch (Throwable e)
                     {
                         e.printStackTrace();
                     }
                 }
                 else
                 {
                     // consider this just an empty skeleton:
                     if (contextFilePath == null)
                     {
                         throw new IllegalArgumentException("the property contextFilePath is required");
                     }
                     try
                     {
                     	IWebBundleDeployerHelper deployerHelper = getWebBundleDeployerHelp(sr);
                     	if (deployerHelper == null)
                     	{
                     		//more warnings?
                     	}
                     	else
                     	{
                     		if (Boolean.TRUE.toString().equals(sr.getProperty(
                     				IWebBundleDeployerHelper.INTERNAL_SERVICE_PROP_UNKNOWN_CONTEXT_HANDLER_TYPE)))
                     		{
                     			contextHandler = null;
                     		}
 	                        ContextHandler handler = deployerHelper.registerContext(contributor,contextFilePath,
 	                        		(String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_EXTRA_CLASSPATH),
 	                        		(String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_BUNDLE_INSTALL_LOCATION_OVERRIDE),
 	                        		(String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_REQUIRE_TLD_BUNDLE),
 	                                contextHandler);
 	                        if (handler != null)
 	                        {
 	                            registerInIndex(handler,sr);
 	                        }
                     	}
                     }
                     catch (Throwable e)
                     {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
                     }
                 }
             }
                 break;
         }
     }
 
     private void registerInIndex(ContextHandler handler, ServiceReference sr)
     {
         _indexByServiceReference.put(sr,handler);
         String key = getSymbolicNameAndContextFileKey(sr);
         if (key != null)
         {
             _indexByContextFile.put(key,sr);
         }
     }
 
     /**
      * Returns the ContextHandler to stop.
      * 
      * @param reg
      * @return the ContextHandler to stop.
      */
     private ContextHandler unregisterInIndex(ServiceReference sr)
     {
         ContextHandler handler = _indexByServiceReference.remove(sr);
         String key = getSymbolicNameAndContextFileKey(sr);
         if (key != null)
         {
             _indexByContextFile.remove(key);
         }
         if (handler == null)
         {
             // a warning?
             return null;
         }
         return handler;
     }
 
     /**
      * @param sr
      * @return The key for a context file within the osgi contexts home folder.
      */
     private String getSymbolicNameAndContextFileKey(ServiceReference sr)
     {
         String contextFilePath = (String)sr.getProperty(OSGiWebappConstants.SERVICE_PROP_CONTEXT_FILE_PATH);
         if (contextFilePath != null)
         {
             return sr.getBundle().getSymbolicName() + "/" + contextFilePath;
         }
         return null;
     }
 
     /**
      * Called by the scanner when one of the context files is changed.
      * 
      * @param contextFileFully
      */
     public void reloadJettyContextHandler(String canonicalNameOfFileChanged, String osgiContextHomeFolderCanonicalPath)
     {
         String key = getNormalizedRelativePath(canonicalNameOfFileChanged, osgiContextHomeFolderCanonicalPath);
         if (key == null)
         {
             return;
         }
         ServiceReference sr = _indexByContextFile.get(key);
         if (sr == null)
         {
             // nothing to do?
             return;
         }
         serviceChanged(new ServiceEvent(ServiceEvent.MODIFIED,sr));
     }
 
     /**
      * @param canFilename
      * @return
      */
     private String getNormalizedRelativePath(String canFilename, String osgiContextHomeFolderCanonicalPath)
     {
         if (!canFilename.startsWith(osgiContextHomeFolderCanonicalPath))
         {
             // why are we here: this does not look like a child of the osgi
             // contexts home.
             // warning?
             return null;
         }
         return canFilename.substring(osgiContextHomeFolderCanonicalPath.length()).replace('\\','/');
     }
     
     /**
      * @return The server on which this webapp is meant to be deployed
      */
     private ServerInstanceWrapper getServerInstanceWrapper(String managedServerName)
     {
     	if (_registry == null)
     	{
     		return null;
     	}
     	if (managedServerName == null)
     	{
     		managedServerName = OSGiServerConstants.MANAGED_JETTY_SERVER_DEFAULT_NAME;
     	}
     	ServerInstanceWrapper wrapper = _registry.getServerInstanceWrapper(managedServerName);
     	//System.err.println("Returning " + managedServerName + "  = " + wrapper);
     	return wrapper;
     }
     
     private IWebBundleDeployerHelper getWebBundleDeployerHelp(ServiceReference sr)
     {
     	if (_registry == null)
     	{
     		return null;
     	}
     	String managedServerName = (String)sr.getProperty(OSGiServerConstants.MANAGED_JETTY_SERVER_NAME);
     	ServerInstanceWrapper wrapper = getServerInstanceWrapper(managedServerName);
     	return wrapper != null ? wrapper.getWebBundleDeployerHelp() : null;
     }
     
 }