/*
    * 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;
  
  import jakarta.servlet.ServletConfig;
  import jakarta.servlet.ServletContext;
  
  import java.io.File;
  import java.io.IOException;
  import java.lang.management.ManagementFactory;
  import java.net.URI;
  import java.net.URISyntaxException;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.nio.file.Path;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Set;
  
  import javax.management.MBeanServer;
  import javax.management.MalformedObjectNameException;
  import javax.management.ObjectName;
  import javax.naming.NamingException;
  
  import org.apache.catalina.Container;
  import org.apache.catalina.Context;
  import org.apache.catalina.Engine;
  import org.apache.catalina.Host;
  import org.apache.catalina.Service;
  import org.apache.catalina.Valve;
  import org.apache.catalina.Wrapper;
  import org.apache.catalina.connector.Connector;
  import org.apache.catalina.core.StandardContext;
  import org.apache.jasper.EmbeddedServletOptions;
  import org.apache.jasper.JspCompilationContext;
  import org.apache.jasper.Options;
  import org.apache.jasper.compiler.Compiler;
  import org.apache.jasper.compiler.JspRuntimeContext;
  import org.apache.naming.ContextBindings;
  import org.apache.naming.factory.ResourceLinkFactory;
  import org.apache.tomcat.util.descriptor.web.ContextResourceLink;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.util.ClassUtils;
  
  import psiprobe.beans.ResourceResolverBean;
  import psiprobe.model.FilterMapping;
  import psiprobe.model.jsp.Item;
  import psiprobe.model.jsp.Summary;
  
  /**
   * Abstraction layer to implement some functionality, which is common between different container
   * adapters.
   */
  public abstract class AbstractTomcatContainer implements TomcatContainer {
  
    /** The logger. */
    protected final Logger logger = LoggerFactory.getLogger(getClass());
  
    /** The Constant NO_JSP_SERVLET. */
    private static final String NO_JSP_SERVLET = "Context '{}' does not have 'JSP' servlet";
  
    /** The host. */
    protected Host host;
  
    /** The connectors. */
    protected Connector[] connectors;
  
    /** The deployer o name. */
    protected ObjectName objectNameDeployer;
  
    /** The mbean server. */
    protected MBeanServer mbeanServer;
  
    /** The Enum FilterMapType. */
    public enum FilterMapType {
  
      /** The url. */
      URL,
  
      /** The servlet name. */
      SERVLET_NAME
    }
  
    @Override
   public void setWrapper(Wrapper wrapper) {
     Valve valve = createValve();
     if (wrapper != null) {
       host = (Host) wrapper.getParent().getParent();
       Engine engine = (Engine) host.getParent();
       Service service = engine.getService();
       connectors = service.findConnectors();
       try {
         objectNameDeployer =
             new ObjectName(host.getParent().getName() + ":type=Deployer,host=" + host.getName());
       } catch (MalformedObjectNameException e) {
         logger.trace("", e);
       }
       host.getPipeline().addValve(valve);
       mbeanServer = ManagementFactory.getPlatformMBeanServer();
     } else if (host != null) {
       host.getPipeline().removeValve(valve);
     }
   }
 
   @Override
   public File getAppBase() {
     File base = Path.of(host.getAppBase()).toFile();
     if (!base.isAbsolute()) {
       base = Path.of(System.getProperty("catalina.base"), host.getAppBase()).toFile();
     }
     return base;
   }
 
   @Override
   public String getConfigBase() {
     Container baseHost = null;
     Container thisContainer = host;
     while (thisContainer != null) {
       if (thisContainer instanceof Host host) {
         baseHost = host;
       }
       thisContainer = thisContainer.getParent();
     }
     File configBase = Path.of(System.getProperty("catalina.base"), "conf").toFile();
     if (baseHost != null) {
       configBase = Path.of(configBase.getPath(), baseHost.getName()).toFile();
     }
     return configBase.getAbsolutePath();
   }
 
   @Override
   public String getHostName() {
     return host.getName();
   }
 
   @Override
   public String getName() {
     return host.getParent().getName();
   }
 
   @Override
   public List<Context> findContexts() {
     List<Context> results = new ArrayList<>();
     for (Container child : host.findChildren()) {
       if (child instanceof Context context) {
         results.add(context);
       }
     }
     return results;
   }
 
   @Override
   public List<Connector> findConnectors() {
     return Collections.unmodifiableList(Arrays.asList(connectors));
   }
 
   @Override
   public boolean installContext(String contextName) throws Exception {
     contextName = formatContextName(contextName);
     installContextInternal(contextName);
     return findContext(contextName) != null;
   }
 
   @Override
   public void stop(String name) throws Exception {
     Context ctx = findContext(name);
     if (ctx != null) {
       ctx.stop();
     }
   }
 
   @Override
   public void start(String name) throws Exception {
     Context ctx = findContext(name);
     if (ctx != null) {
       ctx.start();
     }
   }
 
   @Override
   public void remove(String name) throws Exception {
     name = formatContextName(name);
     Context ctx = findContext(name);
 
     if (ctx != null) {
 
       try {
         stop(name);
       } catch (Exception e) {
         if (name.matches("\\w*")) {
           logger.info("Stopping '{}' threw this exception:", name, e);
         } else {
           logger.info("Stopping and threw this exception:", e);
         }
       }
 
       File appDir;
       File docBase = Path.of(ctx.getDocBase()).toFile();
 
       if (!docBase.isAbsolute()) {
         appDir = Path.of(getAppBase().getPath(), ctx.getDocBase()).toFile();
       } else {
         appDir = docBase;
       }
 
       logger.debug("Deleting '{}'", appDir.getAbsolutePath());
       Utils.delete(appDir);
 
       String warFilename = formatContextFilename(name);
       File warFile = Path.of(getAppBase().getPath(), warFilename + ".war").toFile();
       logger.debug("Deleting '{}'", warFile.getAbsolutePath());
       Utils.delete(warFile);
 
       File configFile = getConfigFile(ctx);
       if (configFile != null) {
         logger.debug("Deleting '{}'", configFile.getAbsolutePath());
         Utils.delete(configFile);
       }
 
       removeInternal(name);
     }
   }
 
   /**
    * Removes the internal.
    *
    * @param name the name
    *
    * @throws Exception the exception
    */
   private void removeInternal(String name) throws Exception {
     checkChanges(name);
   }
 
   @Override
   public void installWar(String name) throws Exception {
     checkChanges(name);
   }
 
   /**
    * Install context internal.
    *
    * @param name the name
    *
    * @throws Exception the exception
    */
   private void installContextInternal(String name) throws Exception {
     checkChanges(name);
   }
 
   @Override
   public Context findContext(String name) {
     String safeName = formatContextName(name);
     if (safeName == null) {
       return null;
     }
     Context result = findContextInternal(safeName);
     if (result == null && safeName.isEmpty()) {
       result = findContextInternal("/");
     }
     return result;
   }
 
   @Override
   public String formatContextName(String name) {
     if (name == null) {
       return null;
     }
     String result = name.trim();
     if (!result.startsWith("/")) {
       result = "/" + result;
     }
     if ("/".equals(result) || "/ROOT".equals(result)) {
       result = "";
     }
     // For ROOT Parallel Deployment, remove "/ROOT"
     if (result.startsWith("/ROOT##")) {
       result = result.substring(5);
     }
     // For ROOT Parallel Usage, remove "/"
     if (result.startsWith("/##")) {
       result = result.substring(1);
     }
     return result;
   }
 
   @Override
   public String formatContextFilename(String contextName) {
     if (contextName == null) {
       return null;
     }
     String result = contextName.trim();
     if (result.startsWith("/")) {
       result = result.substring(1);
     }
     if (result.isEmpty()) {
       return "ROOT";
     }
     // For a context with one or more sub-paths, replace all "/" with "#"
     result = result.replace('/', '#');
     // For ROOT Parallel Usage, prepend "ROOT"
     if (result.startsWith("##")) {
       result = "ROOT" + result;
     }
     return result;
   }
 
   @Override
   public void discardWorkDir(Context context) {
     if (context instanceof StandardContext standardContext) {
       String path = standardContext.getWorkPath();
       logger.info("Discarding '{}'", path);
       Utils.delete(Path.of(path, "org").toFile());
     } else {
       logger.error("context '{}' is not an instance of '{}', expected StandardContext",
           context.getName(), context.getClass().getName());
     }
   }
 
   @Override
   public String getServletFileNameForJsp(Context context, String jspName) {
     String servletName = null;
 
     ServletConfig servletConfig = (ServletConfig) context.findChild("jsp");
     if (servletConfig != null) {
       ServletContext sctx = context.getServletContext();
       Options opt = new EmbeddedServletOptions(servletConfig, sctx);
       JspRuntimeContext jrctx = new JspRuntimeContext(sctx, opt);
       JspCompilationContext jcctx = createJspCompilationContext(jspName, opt, sctx, jrctx, null);
       servletName = jcctx.getServletJavaFileName();
     } else {
       logger.error(NO_JSP_SERVLET, context.getName());
     }
     return servletName;
   }
 
   @Override
   public void recompileJsps(Context context, Summary summary, List<String> names) {
     ServletConfig servletConfig = (ServletConfig) context.findChild("jsp");
     if (servletConfig != null) {
       if (summary != null) {
         synchronized (servletConfig) {
           ServletContext sctx = context.getServletContext();
           Options opt = new EmbeddedServletOptions(servletConfig, sctx);
 
           JspRuntimeContext jrctx = new JspRuntimeContext(sctx, opt);
           /*
            * we need to pass context classloader here, so the jsps can reference /WEB-INF/classes
            * and /WEB-INF/lib. JspCompilationContext would only take URLClassLoader, so we fake it
            */
           try (URLClassLoader classLoader =
               new URLClassLoader(new URL[0], context.getLoader().getClassLoader())) {
             for (String name : names) {
               long time = System.currentTimeMillis();
               JspCompilationContext jcctx =
                   createJspCompilationContext(name, opt, sctx, jrctx, classLoader);
               ClassLoader prevCl = ClassUtils.overrideThreadContextClassLoader(classLoader);
               try {
                 Item item = summary.getItems().get(name);
                 if (item != null) {
                   try {
                     Compiler compiler = jcctx.createCompiler();
                     compiler.compile();
                     item.setState(Item.STATE_READY);
                     item.setException(null);
                     logger.info("Compiled '{}': OK", name);
                   } catch (Exception e) {
                     item.setState(Item.STATE_FAILED);
                     item.setException(e);
                     logger.error("Compiled '{}': FAILED", name, e);
                   }
                   item.setCompileTime(System.currentTimeMillis() - time);
                 } else {
                   logger.error("{} is not on the summary list, ignored", name);
                 }
               } finally {
                 ClassUtils.overrideThreadContextClassLoader(prevCl);
               }
             }
           } catch (IOException e) {
             this.logger.error("", e);
           } finally {
             jrctx.destroy();
           }
         }
       } else {
         logger.error("summary is null for '{}', request ignored", context.getName());
       }
     } else {
       logger.error(NO_JSP_SERVLET, context.getName());
     }
   }
 
   @Override
   public void listContextJsps(Context context, Summary summary, boolean compile) {
     ServletConfig servletConfig = (ServletConfig) context.findChild("jsp");
     if (servletConfig != null) {
       synchronized (servletConfig) {
         ServletContext sctx = context.getServletContext();
         Options opt = new EmbeddedServletOptions(servletConfig, sctx);
 
         JspRuntimeContext jrctx = new JspRuntimeContext(sctx, opt);
         try {
           if (summary.getItems() == null) {
             summary.setItems(new HashMap<>());
           }
 
           /*
            * mark all items as missing
            */
           for (Item item : summary.getItems().values()) {
             item.setMissing(true);
           }
 
           /*
            * we need to pass context classloader here, so the jsps can reference /WEB-INF/classes
            * and /WEB-INF/lib. JspCompilationContext would only take URLClassLoader, so we fake it
            */
           try (URLClassLoader urlcl =
               new URLClassLoader(new URL[0], context.getLoader().getClassLoader())) {
 
             compileItem("/", opt, context, jrctx, summary, urlcl, 0, compile);
           } catch (IOException e) {
             this.logger.error("", e);
           }
         } finally {
           jrctx.destroy();
         }
       }
 
       //
       // delete "missing" items by keeping "not missing" ones
       //
       Map<String, Item> hashMap = new HashMap<>();
       for (Entry<String, Item> entry : summary.getItems().entrySet()) {
         if (!entry.getValue().isMissing()) {
           hashMap.put(entry.getKey(), entry.getValue());
         }
       }
 
       summary.setItems(hashMap);
     } else {
       logger.error(NO_JSP_SERVLET, context.getName());
     }
   }
 
   @Override
   public boolean getAvailable(Context context) {
     return context.getState().isAvailable();
   }
 
   @Override
   public File getConfigFile(Context context) {
     URL configUrl = context.getConfigFile();
     if (configUrl != null) {
       try {
         URI configUri = configUrl.toURI();
         if ("file".equals(configUri.getScheme())) {
           return Path.of(configUri).toFile();
         }
       } catch (URISyntaxException ex) {
         logger.error("Could not convert URL to URI: '{}'", configUrl, ex);
       }
     }
     return null;
   }
 
   @Override
   public void bindToContext(Context context) throws NamingException {
     changeContextBinding(context, true);
   }
 
   @Override
   public void unbindFromContext(Context context) throws NamingException {
     changeContextBinding(context, false);
   }
 
   /**
    * Register access to global resources.
    *
    * @param resourceLink the resource link
    */
   protected void registerGlobalResourceAccess(ContextResourceLink resourceLink) {
     ResourceLinkFactory.registerGlobalResourceAccess(ResourceResolverBean.getGlobalNamingContext(),
         resourceLink.getName(), resourceLink.getGlobal());
   }
 
   /**
    * Change context binding.
    *
    * @param context the context
    * @param bind the bind
    *
    * @throws NamingException the naming exception
    */
   private void changeContextBinding(Context context, boolean bind) throws NamingException {
     Object token = getNamingToken(context);
     ClassLoader loader = Thread.currentThread().getContextClassLoader();
     if (bind) {
       ContextBindings.bindClassLoader(context, token, loader);
     } else {
       ContextBindings.unbindClassLoader(context, token, loader);
     }
   }
 
   /**
    * Lists and optionally compiles a directory recursively.
    *
    * @param jspName name of JSP file or directory to be listed and compiled.
    * @param opt the JSP compiler options
    * @param ctx the context
    * @param jrctx the runtime context used to create the compilation context
    * @param summary the summary in which the output is stored
    * @param classLoader the classloader used by the compiler
    * @param level the depth in the tree at which the item was encountered
    * @param compile whether or not to compile the item or just to check whether it's out of date
    */
   protected void compileItem(String jspName, Options opt, Context ctx, JspRuntimeContext jrctx,
       Summary summary, URLClassLoader classLoader, int level, boolean compile) {
     ServletContext sctx = ctx.getServletContext();
     Set<String> paths = sctx.getResourcePaths(jspName);
 
     if (paths != null) {
       for (String name : paths) {
         boolean isJsp =
             name.endsWith(".jsp") || name.endsWith(".jspx") || opt.getJspConfig().isJspPage(name);
 
         if (isJsp) {
           JspCompilationContext jcctx =
               createJspCompilationContext(name, opt, sctx, jrctx, classLoader);
           ClassLoader prevCl = ClassUtils.overrideThreadContextClassLoader(classLoader);
           try {
             Item item = summary.getItems().get(name);
 
             if (item == null) {
               item = new Item();
               item.setName(name);
             }
 
             item.setLevel(level);
             item.setCompileTime(-1);
 
             Long[] objects = this.getResourceAttributes(name, ctx);
             item.setSize(objects[0]);
             item.setLastModified(objects[1]);
 
             long time = System.currentTimeMillis();
             try {
               Compiler compiler = jcctx.createCompiler();
               if (compile) {
                 compiler.compile();
                 item.setState(Item.STATE_READY);
                 item.setException(null);
               } else if (!compiler.isOutDated()) {
                 item.setState(Item.STATE_READY);
                 item.setException(null);
               } else if (item.getState() != Item.STATE_FAILED) {
                 item.setState(Item.STATE_OOD);
                 item.setException(null);
               }
               logger.info("Compiled '{}': OK", name);
             } catch (Exception e) {
               item.setState(Item.STATE_FAILED);
               item.setException(e);
               logger.info("Compiled '{}': FAILED", name, e);
             }
             if (compile) {
               item.setCompileTime(System.currentTimeMillis() - time);
             }
             item.setMissing(false);
             summary.putItem(name, item);
           } finally {
             ClassUtils.overrideThreadContextClassLoader(prevCl);
           }
         } else {
           compileItem(name, opt, ctx, jrctx, summary, classLoader, level + 1, compile);
         }
       }
     } else {
       logger.debug("getResourcePaths() is null for '{}'. Empty dir? Or Tomcat bug?", jspName);
     }
   }
 
   /**
    * Find context internal.
    *
    * @param name the context name
    *
    * @return the context
    */
   protected Context findContextInternal(String name) {
     return (Context) host.findChild(name);
   }
 
   /**
    * Check changes.
    *
    * @param name the name
    *
    * @throws Exception the exception
    */
   protected void checkChanges(String name) throws Exception {
     Boolean result = (Boolean) mbeanServer.invoke(objectNameDeployer, "tryAddServiced",
         new String[] {name}, new String[] {String.class.getName()});
     if (result.booleanValue()) {
       try {
         mbeanServer.invoke(objectNameDeployer, "check", new String[] {name},
             new String[] {String.class.getName()});
       } finally {
         mbeanServer.invoke(objectNameDeployer, "removeServiced", new String[] {name},
             new String[] {String.class.getName()});
       }
     }
   }
 
   /**
    * Returns the security token required to bind to a naming context.
    *
    * @param context the catalina context
    *
    * @return the security token for use with <code>ContextBindings</code>
    */
   protected abstract Object getNamingToken(Context context);
 
   /**
    * Creates the jsp compilation context.
    *
    * @param name the name
    * @param opt the opt
    * @param sctx the sctx
    * @param jrctx the jrctx
    * @param classLoader the class loader
    *
    * @return the jsp compilation context
    */
   protected abstract JspCompilationContext createJspCompilationContext(String name, Options opt,
       ServletContext sctx, JspRuntimeContext jrctx, ClassLoader classLoader);
 
   /**
    * Creates the valve.
    *
    * @return the valve
    */
   protected abstract Valve createValve();
 
   /**
    * Adds the filter mapping.
    *
    * @param filterName the filter name
    * @param dispatcherMap the dispatcher map
    * @param filterClass the filter class
    * @param types the types as urls or servlet name
    * @param results the results
    * @param filterMapType the filter map type
    */
   protected void addFilterMapping(String filterName, String dispatcherMap, String filterClass,
       String[] types, Collection<FilterMapping> results, FilterMapType filterMapType) {
     for (String type : types) {
       FilterMapping fm = new FilterMapping();
       if (filterMapType == FilterMapType.URL) {
         fm.setUrl(type);
       } else {
         fm.setServletName(type);
       }
       fm.setFilterName(filterName);
       fm.setDispatcherMap(dispatcherMap);
       fm.setFilterClass(filterClass);
       results.add(fm);
     }
   }
 
 }