/*

  * This software is licensed under the Apache License, Version 2.0

  * (the "License") agreement; 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 net.admin4j.ui.servlets;

 import java.io.IOException;

 import java.util.ArrayList;

 import java.util.HashMap;

 import java.util.HashSet;

 import java.util.List;

 import java.util.Map;

 import java.util.Set;

 import java.util.concurrent.ConcurrentHashMap;

 import javax.servlet.ServletConfig;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import net.admin4j.deps.commons.collections.map.ListOrderedMap;

 import net.admin4j.deps.commons.lang3.ArrayUtils;

 import net.admin4j.deps.commons.lang3.StringUtils;

 import net.admin4j.util.Admin4jRuntimeException;

 /**

  * Index page display for all Admin4J Servlets.

  * @author D. Ashmore

  *

  */

 public class Admin4JHomePageServlet extends AdminDisplayServlet {

     private static final long serialVersionUID = -249983381219640941L;

     @SuppressWarnings("rawtypes")

     private static Map<Class, String> requestClassMapping = new ConcurrentHashMap<Class, String>();

     private static Set<String> publicHandleSet = new HashSet<String>();

     @SuppressWarnings("unchecked")

     private static Map<String, HttpServlet> urlMap = new ListOrderedMap();

     private ServletConfig servletConfig;

     private List<Admin4JServlet> servletList = new ArrayList<Admin4JServlet>();

     static {

         requestClassMapping.put(ExceptionDisplayServlet.class, ExceptionDisplayServlet.PUBLIC_HANDLE);

         requestClassMapping.put(HotSpotDisplayServlet.class, HotSpotDisplayServlet.PUBLIC_HANDLE);

         requestClassMapping.put(PerformanceDisplayServlet.class, PerformanceDisplayServlet.PUBLIC_HANDLE);

         requestClassMapping.put(SqlDisplayServlet.class, SqlDisplayServlet.PUBLIC_HANDLE);

         requestClassMapping.put(LogLevelServlet.class, LogLevelServlet.PUBLIC_HANDLE);

         requestClassMapping.put(FileExplorerServlet.class, FileExplorerServlet.PUBLIC_HANDLE);

         requestClassMapping.put(JmxServlet.class, JmxServlet.PUBLIC_HANDLE);

         publicHandleSet.addAll(requestClassMapping.values());

     }

     /* (non-Javadoc)

      * @see javax.servlet.http.HttpServlet#service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

      */

     @Override

     protected void service(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

         if (urlMap.size() == 0) {           

             registerServletMappings(request);

         }

         HttpServlet delegateServlet = urlMap.get(request.getRequestURI());

         if (delegateServlet != null) {

             delegateServlet.service(request, response);

             return;

         }

         request.getSession().setAttribute(ADMIN4J_SESSION_VARIABLE_PREFIX + "IndexUri", request.getRequestURI());

         Map<String,Object> variableMap = new HashMap<String,Object>();

         variableMap.put("servletList", urlMap.entrySet());

         displayFreeMarkerPage(request, response, "admin4jIndexDisplayServlet.ftl", variableMap);

     }

     private void registerServletMappings(HttpServletRequest request) throws ServletException {

         String baseURI = determineBaseUri(request);        

         StringBuffer base = new StringBuffer(baseURI);

         if ( !baseURI.endsWith("/")) {

             base.append("/");

         }

         for (Admin4JServlet servlet: this.servletList) {

             urlMap.put(base + requestClassMapping.get(servlet.getClass()), servlet);

         }

     }

     protected String determineBaseUri(HttpServletRequest request) {

         String baseURI;

         String[] nodes = StringUtils.split(request.getRequestURI(), "/");

         int publicHandleOffset = findPublicHandleOffset(nodes);

         if (publicHandleOffset > 0) {

             baseURI = "/" + StringUtils.join(ArrayUtils.subarray(nodes, 0, publicHandleOffset), "/");

         }

         else {

             baseURI = request.getRequestURI();

         }

         return baseURI;

     }

     private int findPublicHandleOffset(String[] nodes) {

         for (int i = nodes.length - 1; i >= 0; i--) {

             if (publicHandleSet.contains(nodes[i])) {

                 return i;

             }

         }

         return -1;

     }

     @SuppressWarnings("rawtypes")

     private Admin4JServlet initServlet(Class servletClass)

             throws ServletException {

         Admin4JServlet tempServlet;

         try {

             tempServlet = (Admin4JServlet)servletClass.newInstance();

         } catch (Throwable e) {

             throw new Admin4jRuntimeException(e);

         } 

         tempServlet.init(this.servletConfig);

         this.servletList.add(tempServlet);

         return tempServlet;

     }

     @SuppressWarnings("rawtypes")

     private void ensureInitializedServlet(Class servletClass) throws ServletException {

         Set<HttpServlet> servletSet;

         Admin4JServlet tempServlet;

         servletSet = getRegisteredServletSet(servletClass);

         if (servletSet.size() == 0) {

             try {

                 tempServlet = (Admin4JServlet)servletClass.newInstance();

             } catch (Throwable e) {

                 throw new Admin4jRuntimeException(e);

             } 

             tempServlet.init(this.servletConfig);

         }

     }

     /* (non-Javadoc)

      * @see net.admin4j.ui.servlets.Admin4JServlet#getServletLabel()

      */

     @Override

     public String getServletLabel() {

         return "Admin4J Index Page";

     }

     /* (non-Javadoc)

      * @see net.admin4j.ui.servlets.Admin4JServlet#init(javax.servlet.ServletConfig)

      */

     @Override

     public void init(ServletConfig config) throws ServletException {

         super.init(config);

         this.servletConfig = config;

         initServlet(HotSpotDisplayServlet.class);

         initServlet(ExceptionDisplayServlet.class);

         initServlet(FileExplorerServlet.class);

         initServlet(SqlDisplayServlet.class);

         initServlet(JmxServlet.class);

         initServlet(LogLevelServlet.class);

         initServlet(PerformanceDisplayServlet.class);

         ensureInitializedServlet(MemoryMonitorStartupServlet.class);

         ensureInitializedServlet(ThreadMonitorStartupServlet.class);

     }

 }