/*
    * Licensed under the GPL License. You may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *   https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
    *
    * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
    * WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
    * PURPOSE.
   */
  package psiprobe.beans;
  
  import com.maxmind.db.CHMCache;
  import com.maxmind.geoip2.DatabaseReader;
  import com.maxmind.geoip2.exception.AddressNotFoundException;
  import com.maxmind.geoip2.model.CountryResponse;
  import com.maxmind.geoip2.record.Country;
  
  import jakarta.inject.Inject;
  
  import java.net.InetAddress;
  import java.nio.file.Path;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Locale;
  import java.util.Set;
  
  import javax.management.InstanceNotFoundException;
  import javax.management.MBeanServer;
  import javax.management.MBeanServerNotification;
  import javax.management.MalformedObjectNameException;
  import javax.management.Notification;
  import javax.management.NotificationListener;
  import javax.management.ObjectInstance;
  import javax.management.ObjectName;
  import javax.management.RuntimeOperationsException;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import psiprobe.model.Connector;
  import psiprobe.model.RequestProcessor;
  import psiprobe.model.ThreadPool;
  import psiprobe.model.jmx.ThreadPoolObjectName;
  import psiprobe.tools.JmxTools;
  
  /**
   * This class interfaces Tomcat JMX functionality to read connection status. The class essentially
   * provides and maintains the list of connection ThreadPools.
   */
  public class ContainerListenerBean implements NotificationListener {
  
    /** The Constant logger. */
    private static final Logger logger = LoggerFactory.getLogger(ContainerListenerBean.class);
  
    /** The allowed operation. */
    private final Set<String> allowedOperation =
        new HashSet<>(Arrays.asList("start", "stop", "pause", "resume"));
  
    /** The pool names. */
    private List<ThreadPoolObjectName> poolNames;
  
    /** The executor names. */
    private List<ObjectName> executorNames;
  
    /** Used to obtain required {@link MBeanServer} instance. */
    @Inject
    private ContainerWrapperBean containerWrapper;
  
    /**
     * Checks if is initialized.
     *
     * @return true, if is initialized
     */
    private boolean isInitialized() {
      return poolNames != null && !poolNames.isEmpty();
    }
  
    /**
     * Finds ThreadPoolObjectName by its string name.
     *
     * @param name - pool name
     *
     * @return null if the input name is null or ThreadPoolObjectName is not found
     */
    private ThreadPoolObjectName findPool(String name) {
      if (name != null && isInitialized()) {
        for (ThreadPoolObjectName threadPoolObjectName : poolNames) {
          if (name.equals(threadPoolObjectName.getThreadPoolName().getKeyProperty("name"))) {
            return threadPoolObjectName;
          }
        }
      }
      return null;
    }
  
    /**
    * Handles creation and deletion of new "worker" threads.
    *
    * @param notification the notification
    * @param object the object
    */
   @Override
   public synchronized void handleNotification(Notification notification, Object object) {
     if (!(notification instanceof MBeanServerNotification)) {
       return;
     }
 
     if (MBeanServerNotification.REGISTRATION_NOTIFICATION.equals(notification.getType())
         || MBeanServerNotification.UNREGISTRATION_NOTIFICATION.equals(notification.getType())) {
 
       ObjectName objectName = ((MBeanServerNotification) notification).getMBeanName();
       if ("RequestProcessor".equals(objectName.getKeyProperty("type"))) {
         ThreadPoolObjectName threadPoolObjectName = findPool(objectName.getKeyProperty("worker"));
         if (threadPoolObjectName != null) {
           if (MBeanServerNotification.REGISTRATION_NOTIFICATION.equals(notification.getType())) {
             threadPoolObjectName.getRequestProcessorNames().add(objectName);
           } else {
             threadPoolObjectName.getRequestProcessorNames().remove(objectName);
           }
         }
       }
     }
   }
 
   /**
    * Load ObjectNames for the relevant MBeans so they can be queried at a later stage without
    * searching MBean server over and over again.
    *
    * @throws MalformedObjectNameException the malformed object name exception
    * @throws InstanceNotFoundException the instance not found exception
    */
   private synchronized void initialize()
       throws MalformedObjectNameException, InstanceNotFoundException {
 
     MBeanServer server = containerWrapper.getResourceResolver().getMBeanServer();
     String serverName = containerWrapper.getTomcatContainer().getName();
     Set<ObjectInstance> threadPools =
         server.queryMBeans(new ObjectName(serverName + ":type=ThreadPool,name=\"*\""), null);
     poolNames = new ArrayList<>(threadPools.size());
     for (ObjectInstance threadPool : threadPools) {
 
       ThreadPoolObjectName threadPoolObjectName = new ThreadPoolObjectName();
       ObjectName threadPoolName = threadPool.getObjectName();
 
       String name = threadPoolName.getKeyProperty("name");
 
       threadPoolObjectName.setThreadPoolName(threadPoolName);
       ObjectName grpName = server
           .getObjectInstance(new ObjectName(
               threadPoolName.getDomain() + ":type=GlobalRequestProcessor,name=" + name))
           .getObjectName();
       threadPoolObjectName.setGlobalRequestProcessorName(grpName);
 
       /*
        * unfortunately exact workers could not be found at the time of testing so we filter out the
        * relevant workers within the loop
        */
       Set<ObjectInstance> workers = server.queryMBeans(
           new ObjectName(threadPoolName.getDomain() + ":type=RequestProcessor,*"), null);
 
       for (ObjectInstance worker : workers) {
         ObjectName wrkName = worker.getObjectName();
         if (name.equals(wrkName.getKeyProperty("worker"))) {
           threadPoolObjectName.getRequestProcessorNames().add(wrkName);
         }
       }
 
       poolNames.add(threadPoolObjectName);
     }
 
     Set<ObjectInstance> executors =
         server.queryMBeans(new ObjectName(serverName + ":type=Executor,*"), null);
     executorNames = new ArrayList<>(executors.size());
     for (ObjectInstance executor : executors) {
       ObjectName executorName = executor.getObjectName();
       executorNames.add(executorName);
     }
 
     // Register with MBean server
     server.addNotificationListener(new ObjectName("JMImplementation:type=MBeanServerDelegate"),
         this, null, null);
 
   }
 
   /**
    * Gets the thread pools.
    *
    * @return the thread pools
    *
    * @throws Exception the exception
    */
   public synchronized List<ThreadPool> getThreadPools() throws Exception {
     if (!isInitialized()) {
       initialize();
     }
 
     List<ThreadPool> threadPools = new ArrayList<>(poolNames.size());
 
     MBeanServer server = containerWrapper.getResourceResolver().getMBeanServer();
 
     for (ObjectName executorName : executorNames) {
       ThreadPool threadPool = new ThreadPool();
       threadPool.setName(executorName.getKeyProperty("name"));
       threadPool.setMaxThreads(JmxTools.getIntAttr(server, executorName, "maxThreads"));
       threadPool.setMaxSpareThreads(JmxTools.getIntAttr(server, executorName, "largestPoolSize"));
       threadPool.setMinSpareThreads(JmxTools.getIntAttr(server, executorName, "minSpareThreads"));
       threadPool.setCurrentThreadsBusy(JmxTools.getIntAttr(server, executorName, "activeCount"));
       threadPool.setCurrentThreadCount(JmxTools.getIntAttr(server, executorName, "poolSize"));
       threadPools.add(threadPool);
     }
 
     for (ThreadPoolObjectName threadPoolObjectName : poolNames) {
       ObjectName poolName = threadPoolObjectName.getThreadPoolName();
 
       ThreadPool threadPool = new ThreadPool();
       threadPool.setName(poolName.getKeyProperty("name"));
       threadPool.setMaxThreads(JmxTools.getIntAttr(server, poolName, "maxThreads"));
 
       if (JmxTools.hasAttribute(server, poolName, "maxSpareThreads")) {
         threadPool.setMaxSpareThreads(JmxTools.getIntAttr(server, poolName, "maxSpareThreads"));
         threadPool.setMinSpareThreads(JmxTools.getIntAttr(server, poolName, "minSpareThreads"));
       }
 
       threadPool.setCurrentThreadsBusy(JmxTools.getIntAttr(server, poolName, "currentThreadsBusy"));
       threadPool.setCurrentThreadCount(JmxTools.getIntAttr(server, poolName, "currentThreadCount"));
 
       /*
        * Tomcat will return -1 for maxThreads if the connector uses an executor for its threads. In
        * this case, don't add its ThreadPool to the results.
        */
       if (threadPool.getMaxThreads() > -1) {
         threadPools.add(threadPool);
       }
     }
     return threadPools;
   }
 
   /**
    * Toggle connector status.
    *
    * @param operation the operation
    * @param port the port
    *
    * @throws Exception the exception
    */
   public synchronized void toggleConnectorStatus(String operation, String port) throws Exception {
 
     if (!allowedOperation.contains(operation)) {
       logger.error("operation {} not supported", operation);
       throw new IllegalArgumentException("Not support operation");
     }
 
     ObjectName objectName = new ObjectName("Catalina:type=Connector,port=" + port);
 
     MBeanServer server = containerWrapper.getResourceResolver().getMBeanServer();
 
     JmxTools.invoke(server, objectName, operation, null, null);
 
     logger.info("operation {} on Connector {} invoked success", operation, objectName);
   }
 
   /**
    * Gets the connectors.
    *
    * @param includeRequestProcessors the include request processors
    *
    * @return the connectors
    *
    * @throws Exception the exception
    */
   public synchronized List<Connector> getConnectors(boolean includeRequestProcessors)
       throws Exception {
 
     boolean workerThreadNameSupported = true;
 
     if (!isInitialized()) {
       initialize();
     }
 
     List<Connector> connectors = new ArrayList<>(poolNames.size());
 
     MBeanServer server = containerWrapper.getResourceResolver().getMBeanServer();
 
     for (ThreadPoolObjectName threadPoolObjectName : poolNames) {
       ObjectName poolName = threadPoolObjectName.getThreadPoolName();
 
       Connector connector = new Connector();
 
       String name = poolName.getKeyProperty("name");
 
       connector.setProtocolHandler(poolName.getKeyProperty("name"));
 
       if (name.startsWith("\"") && name.endsWith("\"")) {
         name = name.substring(1, name.length() - 1);
       }
 
       String[] arr = name.split("-", -1);
       String port = "-1";
       if (arr.length == 3) {
         port = arr[2];
       }
 
       if (!"-1".equals(port)) {
         String str = "Catalina:type=Connector,port=" + port;
 
         ObjectName objectName = new ObjectName(str);
 
         // add some useful information for connector list
         connector.setStatus(JmxTools.getStringAttr(server, objectName, "stateName"));
         connector.setProtocol(JmxTools.getStringAttr(server, objectName, "protocol"));
         connector
             .setSecure(Boolean.parseBoolean(JmxTools.getStringAttr(server, objectName, "secure")));
         connector.setPort(JmxTools.getIntAttr(server, objectName, "port"));
         connector.setLocalPort(JmxTools.getIntAttr(server, objectName, "localPort"));
         connector.setSchema(JmxTools.getStringAttr(server, objectName, "schema"));
       }
 
       ObjectName grpName = threadPoolObjectName.getGlobalRequestProcessorName();
 
       connector.setMaxTime(JmxTools.getLongAttr(server, grpName, "maxTime"));
       connector.setProcessingTime(JmxTools.getLongAttr(server, grpName, "processingTime"));
       connector.setBytesReceived(JmxTools.getLongAttr(server, grpName, "bytesReceived"));
       connector.setBytesSent(JmxTools.getLongAttr(server, grpName, "bytesSent"));
       connector.setRequestCount(JmxTools.getIntAttr(server, grpName, "requestCount"));
       connector.setErrorCount(JmxTools.getIntAttr(server, grpName, "errorCount"));
 
       if (includeRequestProcessors) {
         List<ObjectName> wrkNames = threadPoolObjectName.getRequestProcessorNames();
         for (ObjectName wrkName : wrkNames) {
           RequestProcessor rp = new RequestProcessor();
           rp.setName(wrkName.getKeyProperty("name"));
           rp.setStage(JmxTools.getIntAttr(server, wrkName, "stage"));
           rp.setProcessingTime(JmxTools.getLongAttr(server, wrkName, "requestProcessingTime"));
           rp.setBytesSent(JmxTools.getLongAttr(server, wrkName, "requestBytesSent"));
           rp.setBytesReceived(JmxTools.getLongAttr(server, wrkName, "requestBytesReceived"));
           try {
             rp.setRemoteAddr(JmxTools.getStringAttr(server, wrkName, "remoteAddr"));
           } catch (RuntimeOperationsException ex) {
             logger.trace("", ex);
           }
 
           if (rp.getRemoteAddr() != null) {
             // Show flag as defined in jvm for localhost
             if (InetAddress.getByName(rp.getRemoteAddr()).isLoopbackAddress()) {
               rp.setRemoteAddrLocale(new Locale(System.getProperty("user.language"),
                   System.getProperty("user.country")));
             } else {
               // Show flag for non-localhost using geo lite
               try (DatabaseReader reader = new DatabaseReader.Builder(
                   Path.of(getClass().getClassLoader().getResource("GeoLite2-Country.mmdb").toURI())
                       .toFile())
                   .withCache(new CHMCache()).build()) {
                 CountryResponse response =
                     reader.country(InetAddress.getByName(rp.getRemoteAddr()));
                 Country country = response.country();
                 rp.setRemoteAddrLocale(new Locale("", country.isoCode()));
               } catch (AddressNotFoundException e) {
                 logger.debug("Address Not Found: {}", e.getMessage());
                 logger.trace("", e);
               }
             }
           }
 
           rp.setVirtualHost(JmxTools.getStringAttr(server, wrkName, "virtualHost"));
           rp.setMethod(JmxTools.getStringAttr(server, wrkName, "method"));
           rp.setCurrentUri(JmxTools.getStringAttr(server, wrkName, "currentUri"));
           rp.setCurrentQueryString(JmxTools.getStringAttr(server, wrkName, "currentQueryString"));
           rp.setProtocol(JmxTools.getStringAttr(server, wrkName, "protocol"));
 
           // Relies on https://issues.apache.org/bugzilla/show_bug.cgi?id=41128
           if (workerThreadNameSupported
               && JmxTools.hasAttribute(server, wrkName, "workerThreadName")) {
 
             rp.setWorkerThreadName(JmxTools.getStringAttr(server, wrkName, "workerThreadName"));
             rp.setWorkerThreadNameSupported(true);
           } else {
             /*
              * attribute should consistently either exist or be missing across all the workers so it
              * does not make sense to check attribute existence if we have found once that it is not
              * supported
              */
             rp.setWorkerThreadNameSupported(false);
             workerThreadNameSupported = false;
           }
           connector.addRequestProcessor(rp);
         }
       }
 
       connectors.add(connector);
     }
     return connectors;
   }
 
 }