/*
    * 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 java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  import java.util.Map;
  
  import javax.inject.Inject;
  import javax.naming.NamingException;
  
  import org.apache.catalina.Context;
  import org.apache.catalina.Wrapper;
  import org.apache.catalina.util.ServerInfo;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.annotation.Value;
  
  import psiprobe.TomcatContainer;
  import psiprobe.model.ApplicationResource;
  
  /**
   * This class wires support for Tomcat "privileged" context functionality into Spring. If
   * application context is privileged Tomcat would always call servlet.setWrapper method on each
   * request. ContainerWrapperBean wires the passed wrapper to the relevant Tomcat container adapter
   * class, which in turn helps the Probe to interpret the wrapper.
   */
  public class ContainerWrapperBean {
  
    /** The Constant logger. */
    private static final Logger logger = LoggerFactory.getLogger(ContainerWrapperBean.class);
  
    /** The tomcat container. */
    private volatile TomcatContainer tomcatContainer;
  
    /** The lock. */
    private final Object lock = new Object();
  
    /** List of class names to adapt particular Tomcat implementation to TomcatContainer interface. */
    @Inject
    private List<String> adapterClasses;
  
    /** The resource resolver. */
    private ResourceResolver resourceResolver;
  
    /** The force first adapter. */
    private boolean forceFirstAdapter;
  
    /** The resource resolvers. */
    @Inject
    private Map<String, ResourceResolver> resourceResolvers;
  
    /**
     * Checks if is force first adapter.
     *
     * @return true, if is force first adapter
     */
    public boolean isForceFirstAdapter() {
      return forceFirstAdapter;
    }
  
    /**
     * Sets the force first adapter. Setting this property to true will override the server polling
     * each adapter performs to test for compatibility. Instead, it will use the first one in the
     * adapterClasses list.
     *
     * @param forceFirstAdapter the new force first adapter
     */
    // TODO We should make this configurable
    @Value("false")
    public void setForceFirstAdapter(boolean forceFirstAdapter) {
      this.forceFirstAdapter = forceFirstAdapter;
    }
  
    /**
     * Sets the wrapper.
     *
     * @param wrapper the new wrapper
     */
    public void setWrapper(Wrapper wrapper) {
      if (tomcatContainer == null) {
  
        synchronized (lock) {
  
          if (tomcatContainer == null) {
  
            String serverInfo = ServerInfo.getServerInfo();
            logger.info("Server info: {}", serverInfo);
            for (String className : adapterClasses) {
              try {
               Object obj = Class.forName(className).getDeclaredConstructor().newInstance();
               logger.debug("Testing container adapter: {}", className);
               if (obj instanceof TomcatContainer) {
                 if (forceFirstAdapter || ((TomcatContainer) obj).canBoundTo(serverInfo)) {
                   logger.info("Using {}", className);
                   tomcatContainer = (TomcatContainer) obj;
                   tomcatContainer.setWrapper(wrapper);
                   break;
                 }
                 logger.debug("Cannot bind {} to {}", className, serverInfo);
               } else {
                 logger.error("{} does not implement {}", className,
                     TomcatContainer.class.getName());
               }
             } catch (Exception e) {
               logger.debug("", e);
               logger.info("Failed to load {}", className);
             }
           }
 
           if (tomcatContainer == null) {
             logger.error("No suitable container adapter found!");
           }
         }
       }
     }
 
     try {
       if (tomcatContainer != null && wrapper == null) {
         logger.info("Unregistering container adapter");
         tomcatContainer.setWrapper(null);
       }
     } catch (Exception e) {
       logger.error("Could not unregister container adapter", e);
     }
   }
 
   /**
    * Gets the tomcat container.
    *
    * @return the tomcat container
    */
   public TomcatContainer getTomcatContainer() {
     return tomcatContainer;
   }
 
   /**
    * Gets the adapter classes.
    *
    * @return the adapter classes
    */
   public List<String> getAdapterClasses() {
     return adapterClasses;
   }
 
   /**
    * Sets the adapter classes.
    *
    * @param adapterClasses the new adapter classes
    */
   public void setAdapterClasses(List<String> adapterClasses) {
     this.adapterClasses = adapterClasses;
   }
 
   /**
    * Gets the resource resolver.
    *
    * @return the resource resolver
    */
   public ResourceResolver getResourceResolver() {
     if (resourceResolver == null) {
       if (System.getProperty("jboss.server.name") != null) {
         resourceResolver = resourceResolvers.get("jboss");
         logger.info("Using JBOSS resource resolver");
       } else {
         resourceResolver = resourceResolvers.get("default");
         logger.info("Using DEFAULT resource resolver");
       }
     }
     return resourceResolver;
   }
 
   /**
    * Gets the resource resolvers.
    *
    * @return the resource resolvers
    */
   public Map<String, ResourceResolver> getResourceResolvers() {
     return resourceResolvers;
   }
 
   /**
    * Sets the resource resolvers.
    *
    * @param resourceResolvers the resource resolvers
    */
   public void setResourceResolvers(Map<String, ResourceResolver> resourceResolvers) {
     this.resourceResolvers = resourceResolvers;
   }
 
   /**
    * Gets the data sources.
    *
    * @return the data sources
    *
    * @throws NamingException the naming exception
    */
   public List<ApplicationResource> getDataSources() throws NamingException {
     List<ApplicationResource> resources = new ArrayList<>(getPrivateDataSources());
     resources.addAll(getGlobalDataSources());
     return resources;
   }
 
   /**
    * Gets the private data sources.
    *
    * @return the private data sources
    *
    * @throws NamingException the naming exception
    */
   public List<ApplicationResource> getPrivateDataSources() throws NamingException {
     List<ApplicationResource> resources = new ArrayList<>();
     if (tomcatContainer != null && getResourceResolver().supportsPrivateResources()) {
       for (Context app : getTomcatContainer().findContexts()) {
         List<ApplicationResource> appResources =
             getResourceResolver().getApplicationResources(app, this);
         // add only those resources that have data source info
         filterDataSources(appResources, resources);
       }
     }
     return resources;
   }
 
   /**
    * Gets the global data sources.
    *
    * @return the global data sources
    *
    * @throws NamingException the naming exception
    */
   public List<ApplicationResource> getGlobalDataSources() throws NamingException {
     List<ApplicationResource> resources = new ArrayList<>();
     if (getResourceResolver().supportsGlobalResources()) {
       List<ApplicationResource> globalResources = getResourceResolver().getApplicationResources();
       // add only those resources that have data source info
       filterDataSources(globalResources, resources);
     }
     return resources;
   }
 
   /**
    * Filter data sources.
    *
    * @param resources the resources
    * @param dataSources the data sources
    */
   protected void filterDataSources(Iterable<ApplicationResource> resources,
       Collection<ApplicationResource> dataSources) {
 
     for (ApplicationResource res : resources) {
       if (res.getDataSourceInfo() != null) {
         dataSources.add(res);
       }
     }
   }
 
 }