/*
    * 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;
  
  import java.io.Serializable;
  import java.util.Objects;
  
  import javax.script.Bindings;
  
  import org.apache.logging.log4j.core.Appender;
  import org.apache.logging.log4j.core.Core;
  import org.apache.logging.log4j.core.Filter;
  import org.apache.logging.log4j.core.Layout;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.config.Configuration;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
  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.config.plugins.validation.constraints.Required;
  import org.apache.logging.log4j.core.script.AbstractScript;
  import org.apache.logging.log4j.core.script.ScriptManager;
  
  @Plugin(name = "ScriptAppenderSelector", category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE, printObject = true)
  public class ScriptAppenderSelector extends AbstractAppender {
  
      /**
       * Builds an appender.
       */
      public static final class Builder implements org.apache.logging.log4j.core.util.Builder<Appender> {
  
          @PluginElement("AppenderSet")
          @Required
          private AppenderSet appenderSet;
  
          @PluginConfiguration
          @Required
          private Configuration configuration;
  
          @PluginBuilderAttribute
          @Required
          private String name;
  
          @PluginElement("Script")
          @Required
          private AbstractScript script;
  
          @Override
          public Appender build() {
              if (name == null) {
                  LOGGER.error("Name missing.");
                  return null;
              }
              if (script == null) {
                  LOGGER.error("Script missing for ScriptAppenderSelector appender {}", name);
                  return null;
              }
              if (appenderSet == null) {
                  LOGGER.error("AppenderSet missing for ScriptAppenderSelector appender {}", name);
                  return null;
              }
              if (configuration == null) {
                  LOGGER.error("Configuration missing for ScriptAppenderSelector appender {}", name);
                  return null;
              }
              final ScriptManager scriptManager = configuration.getScriptManager();
              scriptManager.addScript(script);
              final Bindings bindings = scriptManager.createBindings(script);
              final Object object = scriptManager.execute(script.getName(), bindings);
              final String appenderName = Objects.toString(object, null);
              final Appender appender = appenderSet.createAppender(appenderName, name);
              return appender;
          }
  
          public AppenderSet getAppenderSet() {
              return appenderSet;
          }
  
          public Configuration getConfiguration() {
              return configuration;
          }
  
          public String getName() {
              return name;
         }
 
         public AbstractScript getScript() {
             return script;
         }
 
         public Builder withAppenderNodeSet(@SuppressWarnings("hiding") final AppenderSet appenderSet) {
             this.appenderSet = appenderSet;
             return this;
         }
 
         public Builder withConfiguration(@SuppressWarnings("hiding") final Configuration configuration) {
             this.configuration = configuration;
             return this;
         }
 
         public Builder withName(@SuppressWarnings("hiding") final String name) {
             this.name = name;
             return this;
         }
 
         public Builder withScript(@SuppressWarnings("hiding") final AbstractScript script) {
             this.script = script;
             return this;
         }
 
     }
 
     @PluginBuilderFactory
     public static Builder newBuilder() {
         return new Builder();
     }
 
     private ScriptAppenderSelector(final String name, final Filter filter, final Layout<? extends Serializable> layout) {
         super(name, filter, layout);
     }
 
     @Override
     public void append(final LogEvent event) {
         // Do nothing: This appender is only used to discover and build another appender
     }
 
 }