/*
    * 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.impl;
  
  import java.net.URI;
  
  import org.apache.logging.log4j.core.LoggerContext;
  import org.apache.logging.log4j.core.config.Configuration;
  import org.apache.logging.log4j.core.config.ConfigurationFactory;
  import org.apache.logging.log4j.core.helpers.Constants;
  import org.apache.logging.log4j.core.helpers.Loader;
  import org.apache.logging.log4j.core.selector.ClassLoaderContextSelector;
  import org.apache.logging.log4j.core.selector.ContextSelector;
  import org.apache.logging.log4j.spi.LoggerContextFactory;
  import org.apache.logging.log4j.status.StatusLogger;
  import org.apache.logging.log4j.util.PropertiesUtil;
  
  /**
   * Factory to locate a ContextSelector and then load a LoggerContext.
   */
  public class Log4jContextFactory implements LoggerContextFactory {
  
      private static final StatusLogger LOGGER = StatusLogger.getLogger();
  
      private ContextSelector selector;
  
      /**
       * Constructor that initializes the ContextSelector.
       */
      public Log4jContextFactory() {
          final String sel = PropertiesUtil.getProperties().getStringProperty(Constants.LOG4J_CONTEXT_SELECTOR);
          if (sel != null) {
              try {
                  final Class<?> clazz = Loader.loadClass(sel);
                  if (clazz != null && ContextSelector.class.isAssignableFrom(clazz)) {
                      selector = (ContextSelector) clazz.newInstance();
                  }
              } catch (final Exception ex) {
                  LOGGER.error("Unable to create context " + sel, ex);
              }
          }
          if (selector == null) {
              selector = new ClassLoaderContextSelector();
          }
      }
  
      /**
       * Returns the ContextSelector.
       * @return The ContextSelector.
       */
      public ContextSelector getSelector() {
          return selector;
      }
  
      /**
       * Load the LoggerContext using the ContextSelector.
       * @param fqcn The fully qualified class name of the caller.
       * @param loader The ClassLoader to use or null.
       * @param currentContext If true returns the current Context, if false returns the Context appropriate
       * for the caller if a more appropriate Context can be determined.
       * @param externalContext An external context (such as a ServletContext) to be associated with the LoggerContext.
       * @return The LoggerContext.
       */
      @Override
      public LoggerContext getContext(final String fqcn, final ClassLoader loader, final Object externalContext,
                                      final boolean currentContext) {
          final LoggerContext ctx = selector.getContext(fqcn, loader, currentContext);
          ctx.setExternalContext(externalContext);
          if (ctx.getStatus() == LoggerContext.Status.INITIALIZED) {
              ctx.start();
          }
          return ctx;
      }
  
      /**
       * Load the LoggerContext using the ContextSelector.
       * @param fqcn The fully qualified class name of the caller.
       * @param loader The ClassLoader to use or null.
       * @param externalContext An external context (such as a ServletContext) to be associated with the LoggerContext.
       * @param currentContext If true returns the current Context, if false returns the Context appropriate
       * for the caller if a more appropriate Context can be determined.
       * @param configLocation The location of the configuration for the LoggerContext.
       * @return The LoggerContext.
       */
      @Override
     public LoggerContext getContext(final String fqcn, final ClassLoader loader, final Object externalContext,
                                     final boolean currentContext, final URI configLocation, final String name) {
         final LoggerContext ctx = selector.getContext(fqcn, loader, currentContext, configLocation);
         if (externalContext != null && ctx.getExternalContext() == null) {
             ctx.setExternalContext(externalContext);
         }
         if (ctx.getStatus() == LoggerContext.Status.INITIALIZED) {
             if (configLocation != null || name != null) {
                 ContextAnchor.THREAD_CONTEXT.set(ctx);
                 final Configuration config = ConfigurationFactory.getInstance().getConfiguration(name, configLocation);
                 ctx.start(config);
                 ContextAnchor.THREAD_CONTEXT.remove();
             } else {
                 ctx.start();
             }
         }
         return ctx;
     }
 
     /**
      * Load the LoggerContext using the ContextSelector.
      * @param fqcn The fully qualified class name of the caller.
      * @param loader The ClassLoader to use or null.
      * @param externalContext An external context (such as a ServletContext) to be associated with the LoggerContext.
      * @param currentContext If true returns the current Context, if false returns the Context appropriate
      * for the caller if a more appropriate Context can be determined.
      * @param source The configuration source.
      * @return The LoggerContext.
      */
     public LoggerContext getContext(final String fqcn, final ClassLoader loader, final Object externalContext,
                                     final boolean currentContext, final ConfigurationFactory.ConfigurationSource source) {
         final LoggerContext ctx = selector.getContext(fqcn, loader, currentContext, null);
         if (externalContext != null && ctx.getExternalContext() == null) {
             ctx.setExternalContext(externalContext);
         }
         if (ctx.getStatus() == LoggerContext.Status.INITIALIZED) {
             if (source != null) {
                 ContextAnchor.THREAD_CONTEXT.set(ctx);
                 final Configuration config = ConfigurationFactory.getInstance().getConfiguration(source);
                 ctx.start(config);
                 ContextAnchor.THREAD_CONTEXT.remove();
             } else {
                 ctx.start();
             }
         }
         return ctx;
     }
 
 
 
     /**
      * Removes knowledge of a LoggerContext.
      *
      * @param context The context to remove.
      */
     @Override
     public void removeContext(final org.apache.logging.log4j.spi.LoggerContext context) {
         if (context instanceof LoggerContext) {
             selector.removeContext((LoggerContext) context);
         }
     }
 }