/*
    * 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.config;
  
  import java.net.URI;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.apache.logging.log4j.core.LoggerContext;
  import org.apache.logging.log4j.core.impl.Log4jContextFactory;
  import org.apache.logging.log4j.core.util.NetUtils;
  import org.apache.logging.log4j.spi.LoggerContextFactory;
  import org.apache.logging.log4j.status.StatusLogger;
  import org.apache.logging.log4j.util.Strings;
  
  /**
   * Initializes and configure the Logging system. This class provides several ways to construct a LoggerContext using
   * the location of a configuration file, a context name, and various optional parameters.
   */
  public final class Configurator {
  
      private static final String FQCN = Configurator.class.getName();
  
      private static final Logger LOGGER = StatusLogger.getLogger();
  
      private static Log4jContextFactory getFactory() {
          final LoggerContextFactory factory = LogManager.getFactory();
          if (factory instanceof Log4jContextFactory) {
              return (Log4jContextFactory) factory;
          } else if (factory != null) {
              LOGGER.error("LogManager returned an instance of {} which does not implement {}. Unable to initialize Log4j.",
                      factory.getClass().getName(), Log4jContextFactory.class.getName());
              return null;
          } else {
              LOGGER.fatal("LogManager did not return a LoggerContextFactory. This indicates something has gone terribly wrong!");
              return null;
          }
      }
  
      /**
       * Initializes the Logging Context.
       * @param loader The ClassLoader for the Context (or null).
       * @param source The InputSource for the configuration.
       * @return The LoggerContext.
       */
      public static LoggerContext initialize(final ClassLoader loader,
                                             final ConfigurationSource source) {
          return initialize(loader, source, null);
      }
  
      /**
       * Initializes the Logging Context.
       * @param loader The ClassLoader for the Context (or null).
       * @param source The InputSource for the configuration.
       * @param externalContext The external context to be attached to the LoggerContext.
       * @return The LoggerContext.
       */
  
      public static LoggerContext initialize(final ClassLoader loader,
                                             final ConfigurationSource source,
                                             final Object externalContext)
      {
  
          try {
              final Log4jContextFactory factory = getFactory();
              return factory == null ? null :
                      factory.getContext(FQCN, loader, externalContext, false, source);
          } catch (final Exception ex) {
              LOGGER.error("There was a problem obtaining a LoggerContext using the configuration source [{}]", source, ex);
          }
          return null;
      }
  
      /**
       * Initializes the Logging Context.
       * @param name The Context name.
       * @param loader The ClassLoader for the Context (or null).
       * @param configLocation The configuration for the logging context.
       * @return The LoggerContext or null if an error occurred (check the status logger).
       */
      public static LoggerContext initialize(final String name, final ClassLoader loader, final String configLocation) {
         return initialize(name, loader, configLocation, null);
 
     }
 
     /**
      * Initializes the Logging Context.
      * @param name The Context name.
      * @param loader The ClassLoader for the Context (or null).
      * @param configLocation The configuration for the logging context (or null, or blank).
      * @param externalContext The external context to be attached to the LoggerContext
      * @return The LoggerContext or null if an error occurred (check the status logger).
      */
     public static LoggerContext initialize(final String name, final ClassLoader loader, final String configLocation,
             final Object externalContext) {
         if (Strings.isBlank(configLocation)) {
             return initialize(name, loader, (URI) null, externalContext);
         }
         if (configLocation.contains(",")) {
             final String[] parts = configLocation.split(",");
             String scheme = null;
             final List<URI> uris = new ArrayList<>(parts.length);
             for (final String part : parts) {
                 final URI uri = NetUtils.toURI(scheme != null ? scheme + ":" + part.trim() : part.trim());
                 if (scheme == null && uri.getScheme() != null) {
                     scheme = uri.getScheme();
                 }
                 uris.add(uri);
             }
             return initialize(name, loader, uris, externalContext);
         } else {
             return initialize(name, loader, NetUtils.toURI(configLocation), externalContext);
         }
     }
 
     /**
      * Initializes the Logging Context.
      * @param name The Context name.
      * @param loader The ClassLoader for the Context (or null).
      * @param configLocation The configuration for the logging context.
      * @return The LoggerContext.
      */
     public static LoggerContext initialize(final String name, final ClassLoader loader, final URI configLocation) {
         return initialize(name, loader, configLocation, null);
     }
 
     /**
      * Initializes the Logging Context.
      * @param name The Context name.
      * @param loader The ClassLoader for the Context (or null).
      * @param configLocation The configuration for the logging context (or null).
      * @param externalContext The external context to be attached to the LoggerContext
      * @return The LoggerContext.
      */
     public static LoggerContext initialize(final String name, final ClassLoader loader, final URI configLocation,
                                            final Object externalContext) {
 
         try {
             final Log4jContextFactory factory = getFactory();
             return factory == null ? null :
                     factory.getContext(FQCN, loader, externalContext, false, configLocation, name);
         } catch (final Exception ex) {
             LOGGER.error("There was a problem initializing the LoggerContext [{}] using configuration at [{}].",
                     name, configLocation, ex);
         }
         return null;
     }
 
     public static LoggerContext initialize(final String name, final ClassLoader loader, final List<URI> configLocations,
             final Object externalContext) {
         try {
             final Log4jContextFactory factory = getFactory();
             return factory == null ?
                     null :
                     factory.getContext(FQCN, loader, externalContext, false, configLocations, name);
         } catch (final Exception ex) {
             LOGGER.error("There was a problem initializing the LoggerContext [{}] using configurations at [{}].", name,
                     configLocations, ex);
         }
         return null;
     }
 
     /**
      * Initializes the Logging Context.
      * @param name The Context name.
      * @param configLocation The configuration for the logging context.
      * @return The LoggerContext or null if an error occurred (check the status logger).
      */
     public static LoggerContext initialize(final String name, final String configLocation) {
         return initialize(name, null, configLocation);
     }
 
     /**
      * Initializes the Logging Context.
      * @param configuration The Configuration.
      * @return The LoggerContext.
      */
     public static LoggerContext initialize(final Configuration configuration) {
         return initialize(null, configuration, null);
     }
 
     /**
      * Initializes the Logging Context.
      * @param loader The ClassLoader.
      * @param configuration The Configuration.
      * @return The LoggerContext.
      */
     public static LoggerContext initialize(final ClassLoader loader, final Configuration configuration) {
         return initialize(loader, configuration, null);
     }
 
     /**
      * Initializes the Logging Context.
      * @param loader The ClassLoader.
      * @param configuration The Configuration.
      * @param externalContext - The external context to be attached to the LoggerContext.
      * @return The LoggerContext.
      */
     public static LoggerContext initialize(final ClassLoader loader, final Configuration configuration, final Object externalContext) {
         try {
             final Log4jContextFactory factory = getFactory();
             return factory == null ? null :
                     factory.getContext(FQCN, loader, externalContext, false, configuration);
         } catch (final Exception ex) {
             LOGGER.error("There was a problem initializing the LoggerContext using configuration {}",
                     configuration.getName(), ex);
         }
         return null;
     }
 
     /**
      * Sets the levels of <code>parentLogger</code> and all 'child' loggers to the given <code>level</code>.
      * @param parentLogger the parent logger
      * @param level the new level
      */
     public static void setAllLevels(final String parentLogger, final Level level) {
         // 1) get logger config
         // 2) if exact match, use it, if not, create it.
         // 3) set level on logger config
         // 4) update child logger configs with level
         // 5) update loggers
         final LoggerContext loggerContext = LoggerContext.getContext(false);
         final Configuration config = loggerContext.getConfiguration();
         boolean set = setLevel(parentLogger, level, config);
         for (final Map.Entry<String, LoggerConfig> entry : config.getLoggers().entrySet()) {
             if (entry.getKey().startsWith(parentLogger)) {
                 set |= setLevel(entry.getValue(), level);
             }
         }
         if (set) {
             loggerContext.updateLoggers();
         }
     }
 
     private static boolean setLevel(final LoggerConfig loggerConfig, final Level level) {
         final boolean set = !loggerConfig.getLevel().equals(level);
         if (set) {
             loggerConfig.setLevel(level);
         }
         return set;
     }
 
     /**
      * Sets logger levels.
      *
      * @param levelMap
      *            a levelMap where keys are level names and values are new
      *            Levels.
      */
     public static void setLevel(final Map<String, Level> levelMap) {
         final LoggerContext loggerContext = LoggerContext.getContext(false);
         final Configuration config = loggerContext.getConfiguration();
         boolean set = false;
         for (final Map.Entry<String, Level> entry : levelMap.entrySet()) {
             final String loggerName = entry.getKey();
             final Level level = entry.getValue();
             set |= setLevel(loggerName, level, config);
         }
         if (set) {
             loggerContext.updateLoggers();
         }
     }
 
     /**
      * Sets a logger's level.
      *
      * @param loggerName
      *            the logger name
      * @param level
      *            the new level
      */
     public static void setLevel(final String loggerName, final Level level) {
         final LoggerContext loggerContext = LoggerContext.getContext(false);
         if (Strings.isEmpty(loggerName)) {
             setRootLevel(level);
         } else {
             if (setLevel(loggerName, level, loggerContext.getConfiguration())) {
                 loggerContext.updateLoggers();
             }
         }
     }
 
     private static boolean setLevel(final String loggerName, final Level level, final Configuration config) {
         boolean set;
         LoggerConfig loggerConfig = config.getLoggerConfig(loggerName);
         if (!loggerName.equals(loggerConfig.getName())) {
             // TODO Should additivity be inherited?
             loggerConfig = new LoggerConfig(loggerName, level, true);
             config.addLogger(loggerName, loggerConfig);
             loggerConfig.setLevel(level);
             set = true;
         } else {
             set = setLevel(loggerConfig, level);
         }
         return set;
     }
 
     /**
      * Sets the root logger's level.
      *
      * @param level
      *            the new level
      */
     public static void setRootLevel(final Level level) {
         final LoggerContext loggerContext = LoggerContext.getContext(false);
         final LoggerConfig loggerConfig = loggerContext.getConfiguration().getRootLogger();
         if (!loggerConfig.getLevel().equals(level)) {
             loggerConfig.setLevel(level);
             loggerContext.updateLoggers();
         }
     }
 
     /**
      * Shuts down the given logging context.
      * @param ctx the logging context to shut down, may be null.
      */
     public static void shutdown(final LoggerContext ctx) {
         if (ctx != null) {
             ctx.stop();
         }
     }
 
     private Configurator() {
         // empty
     }
 }