/*

  * 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.Collections;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 import java.util.Set;

 import java.util.StringTokenizer;

 import javax.servlet.ServletConfig;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import net.admin4j.config.Admin4JConfiguration;

 import net.admin4j.deps.commons.beanutils.BeanComparator;

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

 import net.admin4j.entity.ExceptionInfo;

 import net.admin4j.exception.ExceptionTracker;

 import net.admin4j.log.LogManager;

 import net.admin4j.log.LogManagerRegistry;

 import net.admin4j.util.Admin4jRuntimeException;

 import net.admin4j.util.FreemarkerUtils;

 import net.admin4j.util.GuiUtils;

 import net.admin4j.util.HostUtils;

 import net.admin4j.util.ServletUtils;

 import net.admin4j.vo.ExceptionStatisticVO;

 /**

  * Provides a browser for exception statistics intercepted by the Exception Tracker.  By default,

  * exceptions logged by Java Util Logging and Log4J are automatically tracked if they are present in the classpath.

  * 

  *  <p>Should you use other logging frameworks, you can have those exceptions tracked by writingand installing a custom

  *  appender for that framework.  See <a href="../../exception/Log4JExceptionAppender.html">Log4JExceptionAppender</a>

  *  for an example.</p>

  *  

  *  <p>You will need to map this servlet to an url pattern (e.g. '/admin4j/error').</p>

  *  <p>This servlet does <b>not</b> require other web resources.</p>

  *  

  *  <p>Init parameters for this servlet are as follows:</p>

  *  <li>tracking.time.in.days -- Optional.  Default 30 days.  Amount of time an exception will be tracked and reportable.</li>

  *  <li>exempted.exception.types -- Optional.  Comma delimited list of exception class names that will *not* be tracked.</li>

  * @author D. Ashmore

  * @see net.admin4j.exception.ExceptionTracker

  */

 public class ExceptionDisplayServlet extends AdminDisplayServlet {

     private static final long serialVersionUID = -2262926722396897223L;

     public static final String PUBLIC_HANDLE="exception";

     /* (non-Javadoc)

      * @see javax.servlet.GenericServlet#init(javax.servlet.ServletConfig)

      */

     @Override

     public void init(ServletConfig config) throws ServletException {

         super.init(config);

        for (LogManager logManager: LogManagerRegistry.getAvailableLogManagerSet()) {

            try {

                logManager.installExceptionTrackingLogAppender();

                logger.info("Exception tracking for {} installed.", logManager.getLoggerSoftwareProductName());

            }

            catch (Throwable t) {

                logger.error("Exception tracking for {} installed.", 

                        new Admin4jRuntimeException(t).addContextValue("log manager", logManager.getLoggerSoftwareProductName()));

            }

        }

        String trackingTimeStr = ServletUtils.getConfigurationSetting(

                new String[]{PUBLIC_HANDLE + ".tracking.time.in.days", 

                "tracking.time.in.days"}, config);

        Integer trackingTimeInDays;

        if ( !StringUtils.isEmpty(trackingTimeStr)) {

            try {

                trackingTimeInDays = new Integer(trackingTimeStr.trim());

                ExceptionTracker.setPurgeThresholdInDays(trackingTimeInDays);

            }

            catch (Throwable t) {

                this.logger.error("Invalid tracking.time.in.millis parameter for ExceptionDisplayServlet.  Default used.  tracking.time.in.millis="+ trackingTimeStr, 

                        t);

            }

        }

        else if (Admin4JConfiguration.getExceptionTimeTrackingInDays() != null) {

            ExceptionTracker.setPurgeThresholdInDays(Admin4JConfiguration.getExceptionTimeTrackingInDays());

        }

        String exemptedExceptionStr = ServletUtils.getConfigurationSetting(

                new String[]{PUBLIC_HANDLE + ".exempted.exception.types", 

                "exempted.exception.types"}, config);

        if ( !StringUtils.isEmpty(exemptedExceptionStr)) {

            registerExceptedExceptionTypes(exemptedExceptionStr);

        }

        else if ( !StringUtils.isEmpty(Admin4JConfiguration.getExceptionExemptedExceptionTypes() )) {

            registerExceptedExceptionTypes(Admin4JConfiguration.getExceptionExemptedExceptionTypes());

        }

     }

     private void registerExceptedExceptionTypes(String exemptedExceptionStr) {

         try {

                StringTokenizer tok = new StringTokenizer(exemptedExceptionStr, ",");

                String exemptedClassName;

                while (tok.hasMoreTokens()) {

                    exemptedClassName = tok.nextToken();

                    if (!StringUtils.isEmpty(exemptedClassName)) {

                        ExceptionTracker.addExemptedExceptionClassName(exemptedClassName);

                        this.logger.info("Exceptions of type {} will not be tracked.", exemptedClassName);

                    }

                }

            }

            catch (Throwable t) {

                this.logger.error("Invalid exempted.exception.types parameter for ExceptionDisplayServlet.  parm=" + exemptedExceptionStr, 

                        t);

            }

     }

     /* (non-Javadoc)

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

      */

     @SuppressWarnings("unchecked")

     @Override

     protected void service(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

         String actionStr = request.getParameter("action");

         if ( !StringUtils.isEmpty(actionStr)) {

 //            if ("save".equalsIgnoreCase(actionStr)) {

 //                ExceptionTracker.recordUrl(request.getParameter("exceptionId"), request.getParameter("exceptionUrl"));

 //            }

             if ("delete".equalsIgnoreCase(actionStr)) {

                 ExceptionTracker.deleteException(request.getParameter("exceptionId"));

             }

             if ("text".equalsIgnoreCase(actionStr)) {

                 ExceptionInfo eInfo = ExceptionTracker.lookupException(request.getParameter("exceptionId"));

                 response.setContentType("application/octet-stream");                 

                 response.setHeader("Content-disposition", "attachment; filename=\"exception.txt\"");

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

                 variableMap.put("exception", eInfo);

                 variableMap.put("host", HostUtils.getHostName());

                 variableMap.put("GuiUtils", new GuiUtils());

                 FreemarkerUtils.addConfiguration(variableMap);

                 this.displayFreeMarkerResponse(request, response, "exceptionDownload.ftl", variableMap);

                 return;

             }

         }

         Set<ExceptionStatisticVO> exceptionSet = ExceptionTracker.getExceptionStatisticSet();

         List<ExceptionStatisticVO> exceptionList = new ArrayList<ExceptionStatisticVO>(exceptionSet);

         Collections.sort(exceptionList, new BeanComparator("totalNbrExceptions"));

         Collections.reverse(exceptionList);

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

         variableMap.put("exceptionList", exceptionList);

         variableMap.put("GuiUtils", new GuiUtils());

         FreemarkerUtils.addConfiguration(variableMap);

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

     }

     /* (non-Javadoc)

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

      */

     @Override

     public String getServletLabel() {

         return "Exception Summary";

     }

 }