/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements. See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache license, Version 2.0
    * (the "License"); 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 org.apache.logging.log4j.core.appender.routing;
  
  import java.util.Collections;
  import java.util.Map;
  import java.util.Objects;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ConcurrentMap;
  import java.util.concurrent.TimeUnit;
  
  import javax.script.Bindings;
  
  import org.apache.logging.log4j.core.Appender;
  import org.apache.logging.log4j.core.Filter;
  import org.apache.logging.log4j.core.LifeCycle2;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.appender.AbstractAppender;
  import org.apache.logging.log4j.core.appender.rewrite.RewritePolicy;
  import org.apache.logging.log4j.core.config.AppenderControl;
  import org.apache.logging.log4j.core.config.Configuration;
  import org.apache.logging.log4j.core.config.Node;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
  import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
  import org.apache.logging.log4j.core.config.plugins.PluginElement;
  import org.apache.logging.log4j.core.script.AbstractScript;
  import org.apache.logging.log4j.core.script.ScriptManager;
  import org.apache.logging.log4j.core.util.Booleans;
  
  /**
   * This Appender "routes" between various Appenders, some of which can be references to
   * Appenders defined earlier in the configuration while others can be dynamically created
   * within this Appender as required. Routing is achieved by specifying a pattern on
   * the Routing appender declaration. The pattern should contain one or more substitution patterns of
   * the form "$${[key:]token}". The pattern will be resolved each time the Appender is called using
   * the built in StrSubstitutor and the StrLookup plugin that matches the specified key.
   */
  @Plugin(name = "Routing", category = "Core", elementType = Appender.ELEMENT_TYPE, printObject = true)
  public final class RoutingAppender extends AbstractAppender {
  
      public static final String STATIC_VARIABLES_KEY = "staticVariables";
  
      public static class Builder<B extends Builder<B>> extends AbstractAppender.Builder<B>
              implements org.apache.logging.log4j.core.util.Builder<RoutingAppender> {
  
          // Does not work unless the element is called "Script", I wanted "DefaultRounteScript"...
          @PluginElement("Script")
          private AbstractScript defaultRouteScript;
  
          @PluginElement("Routes")
          private Routes routes;
  
          @PluginConfiguration
          private Configuration configuration;
  
          @PluginElement("RewritePolicy")
          private RewritePolicy rewritePolicy;
  
          @PluginElement("PurgePolicy")
          private PurgePolicy purgePolicy;
  
          @Override
          public RoutingAppender build() {
              final String name = getName();
              if (name == null) {
                  LOGGER.error("No name defined for this RoutingAppender");
                  return null;
              }
              if (routes == null) {
                  LOGGER.error("No routes defined for RoutingAppender {}", name);
                  return null;
              }
              return new RoutingAppender(name, getFilter(), isIgnoreExceptions(), routes, rewritePolicy,
                      configuration, purgePolicy, defaultRouteScript);
          }
  
          public Routes getRoutes() {
              return routes;
          }
  
          public Configuration getConfiguration() {
              return configuration;
          }
  
         public AbstractScript getDefaultRouteScript() {
             return defaultRouteScript;
         }
 
         public RewritePolicy getRewritePolicy() {
             return rewritePolicy;
         }
 
         public PurgePolicy getPurgePolicy() {
             return purgePolicy;
         }
 
         public B withRoutes(@SuppressWarnings("hiding") final Routes routes) {
             this.routes = routes;
             return asBuilder();
         }
 
         public B withConfiguration(@SuppressWarnings("hiding") final Configuration configuration) {
             this.configuration = configuration;
             return asBuilder();
         }
 
         public B withDefaultRouteScript(@SuppressWarnings("hiding") final AbstractScript defaultRouteScript) {
             this.defaultRouteScript = defaultRouteScript;
             return asBuilder();
         }
 
         public B withRewritePolicy(@SuppressWarnings("hiding") final RewritePolicy rewritePolicy) {
             this.rewritePolicy = rewritePolicy;
             return asBuilder();
         }
 
         public void withPurgePolicy(@SuppressWarnings("hiding") final PurgePolicy purgePolicy) {
             this.purgePolicy = purgePolicy;
         }
 
     }
 
     @PluginBuilderFactory
     public static <B extends Builder<B>> B newBuilder() {
         return new Builder<B>().asBuilder();
     }
 
     private static final String DEFAULT_KEY = "ROUTING_APPENDER_DEFAULT";
 
     private final Routes routes;
     private Route defaultRoute;
     private final Configuration configuration;
     private final ConcurrentMap<String, AppenderControl> appenders = new ConcurrentHashMap<>();
     private final RewritePolicy rewritePolicy;
     private final PurgePolicy purgePolicy;
     private final AbstractScript defaultRouteScript;
     private final ConcurrentMap<Object, Object> scriptStaticVariables = new ConcurrentHashMap<>();
 
     private RoutingAppender(final String name, final Filter filter, final boolean ignoreExceptions, final Routes routes,
             final RewritePolicy rewritePolicy, final Configuration configuration, final PurgePolicy purgePolicy,
             final AbstractScript defaultRouteScript) {
         super(name, filter, null, ignoreExceptions);
         this.routes = routes;
         this.configuration = configuration;
         this.rewritePolicy = rewritePolicy;
         this.purgePolicy = purgePolicy;
         if (this.purgePolicy != null) {
             this.purgePolicy.initialize(this);
         }
         this.defaultRouteScript = defaultRouteScript;
         Route defRoute = null;
         for (final Route route : routes.getRoutes()) {
             if (route.getKey() == null) {
                 if (defRoute == null) {
                     defRoute = route;
                 } else {
                     error("Multiple default routes. Route " + route.toString() + " will be ignored");
                 }
             }
         }
         defaultRoute = defRoute;
     }
 
     @Override
     public void start() {
         if (defaultRouteScript != null) {
             if (configuration == null) {
                 error("No Configuration defined for RoutingAppender; required for Script element.");
             } else {
                 final ScriptManager scriptManager = configuration.getScriptManager();
                 scriptManager.addScript(defaultRouteScript);
                 final Bindings bindings = scriptManager.createBindings(defaultRouteScript);
                 bindings.put(STATIC_VARIABLES_KEY, scriptStaticVariables);
                 final Object object = scriptManager.execute(defaultRouteScript.getName(), bindings);
                 final Route route = routes.getRoute(Objects.toString(object, null));
                 if (route != null) {
                     defaultRoute = route;
                 }
             }
         }
         // Register all the static routes.
         for (final Route route : routes.getRoutes()) {
             if (route.getAppenderRef() != null) {
                 final Appender appender = configuration.getAppender(route.getAppenderRef());
                 if (appender != null) {
                     final String key = route == defaultRoute ? DEFAULT_KEY : route.getKey();
                     appenders.put(key, new AppenderControl(appender, null, null));
                 } else {
                     error("Appender " + route.getAppenderRef() + " cannot be located. Route ignored");
                 }
             }
         }
         super.start();
     }
 
     @Override
     public boolean stop(final long timeout, final TimeUnit timeUnit) {
         setStopping();
         super.stop(timeout, timeUnit, false);
         final Map<String, Appender> map = configuration.getAppenders();
         for (final Map.Entry<String, AppenderControl> entry : appenders.entrySet()) {
             final Appender appender = entry.getValue().getAppender();
             if (!map.containsKey(appender.getName())) {
                 if (appender instanceof LifeCycle2) {
                     ((LifeCycle2) appender).stop(timeout, timeUnit);
                 } else {
                     appender.stop();
                 }
             }
         }
         setStopped();
         return true;
     }
 
     @Override
     public void append(LogEvent event) {
         if (rewritePolicy != null) {
             event = rewritePolicy.rewrite(event);
         }
         final String pattern = routes.getPattern(event, scriptStaticVariables);
         final String key = pattern != null ? configuration.getStrSubstitutor().replace(event, pattern) : defaultRoute.getKey();
         final AppenderControl control = getControl(key, event);
         if (control != null) {
             control.callAppender(event);
         }
 
         if (purgePolicy != null) {
             purgePolicy.update(key, event);
         }
     }
 
     private synchronized AppenderControl getControl(final String key, final LogEvent event) {
         AppenderControl control = appenders.get(key);
         if (control != null) {
             return control;
         }
         Route route = null;
         for (final Route r : routes.getRoutes()) {
             if (r.getAppenderRef() == null && key.equals(r.getKey())) {
                 route = r;
                 break;
             }
         }
         if (route == null) {
             route = defaultRoute;
             control = appenders.get(DEFAULT_KEY);
             if (control != null) {
                 return control;
             }
         }
         if (route != null) {
             final Appender app = createAppender(route, event);
             if (app == null) {
                 return null;
             }
             control = new AppenderControl(app, null, null);
             appenders.put(key, control);
         }
 
         return control;
     }
 
     private Appender createAppender(final Route route, final LogEvent event) {
         final Node routeNode = route.getNode();
         for (final Node node : routeNode.getChildren()) {
             if (node.getType().getElementName().equals(Appender.ELEMENT_TYPE)) {
                 final Node appNode = new Node(node);
                 configuration.createConfiguration(appNode, event);
                 if (appNode.getObject() instanceof Appender) {
                     final Appender app = appNode.getObject();
                     app.start();
                     return app;
                 }
                 error("Unable to create Appender of type " + node.getName());
                 return null;
             }
         }
         error("No Appender was configured for route " + route.getKey());
         return null;
     }
 
     public Map<String, AppenderControl> getAppenders() {
         return Collections.unmodifiableMap(appenders);
     }
 
     /**
      * Deletes the specified appender.
      *
      * @param key The appender's key
      */
     public void deleteAppender(final String key) {
         LOGGER.debug("Deleting route with " + key + " key ");
         final AppenderControl control = appenders.remove(key);
         if (null != control) {
             LOGGER.debug("Stopping route with " + key + " key");
             control.getAppender().stop();
         } else {
             LOGGER.debug("Route with " + key + " key already deleted");
         }
     }
 
     /**
      * Creates a RoutingAppender.
      * @param name The name of the Appender.
      * @param ignore If {@code "true"} (default) exceptions encountered when appending events are logged; otherwise
      *               they are propagated to the caller.
      * @param routes The routing definitions.
      * @param config The Configuration (automatically added by the Configuration).
      * @param rewritePolicy A RewritePolicy, if any.
      * @param filter A Filter to restrict events processed by the Appender or null.
      * @return The RoutingAppender
      * @deprecated Since 2.7; use {@link #newBuilder()}
      */
     @Deprecated
     public static RoutingAppender createAppender(
             final String name,
             final String ignore,
             final Routes routes,
             final Configuration config,
             final RewritePolicy rewritePolicy,
             final PurgePolicy purgePolicy,
             final Filter filter) {
 
         final boolean ignoreExceptions = Booleans.parseBoolean(ignore, true);
         if (name == null) {
             LOGGER.error("No name provided for RoutingAppender");
             return null;
         }
         if (routes == null) {
             LOGGER.error("No routes defined for RoutingAppender");
             return null;
         }
         return new RoutingAppender(name, filter, ignoreExceptions, routes, rewritePolicy, config, purgePolicy, null);
     }
 
     public Route getDefaultRoute() {
         return defaultRoute;
     }
 
     public AbstractScript getDefaultRouteScript() {
         return defaultRouteScript;
     }
 
     public PurgePolicy getPurgePolicy() {
         return purgePolicy;
     }
 
     public RewritePolicy getRewritePolicy() {
         return rewritePolicy;
     }
 
     public Routes getRoutes() {
         return routes;
     }
 
     public Configuration getConfiguration() {
         return configuration;
     }
 
     public ConcurrentMap<Object, Object> getScriptStaticVariables() {
         return scriptStaticVariables;
     }
 }