/*
    * 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.HashMap;
  import java.util.Map;
  import java.util.concurrent.TimeUnit;
  
  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.net.Advertiser;
  import org.apache.logging.log4j.core.util.Booleans;
  import org.apache.logging.log4j.core.util.Integers;
  
  /**
   * Memory Mapped File Appender.
   *
   * @since 2.1
   */
  @Plugin(name = "MemoryMappedFile", category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE, printObject = true)
  public final class MemoryMappedFileAppender extends AbstractOutputStreamAppender<MemoryMappedFileManager> {
  
      /**
       * Builds RandomAccessFileAppender instances.
       * 
       * @param <B>
       *            The type to build
       */
      public static class Builder<B extends Builder<B>> extends AbstractOutputStreamAppender.Builder<B>
              implements org.apache.logging.log4j.core.util.Builder<MemoryMappedFileAppender> {
  
          @PluginBuilderAttribute("fileName")
          private String fileName;
  
          @PluginBuilderAttribute("append")
          private boolean append = true;
  
          @PluginBuilderAttribute("regionLength")
          private int regionLength = MemoryMappedFileManager.DEFAULT_REGION_LENGTH;
  
          @PluginBuilderAttribute("advertise")
          private boolean advertise;
  
          @PluginBuilderAttribute("advertiseURI")
          private String advertiseURI;
  
          @Override
          public MemoryMappedFileAppender build() {
              final String name = getName();
              final int actualRegionLength = determineValidRegionLength(name, regionLength);
  
              if (name == null) {
                  LOGGER.error("No name provided for MemoryMappedFileAppender");
                  return null;
              }
  
              if (fileName == null) {
                  LOGGER.error("No filename provided for MemoryMappedFileAppender with name " + name);
                  return null;
              }
              final Layout<? extends Serializable> layout = getOrCreateLayout();
              final MemoryMappedFileManager manager = MemoryMappedFileManager.getFileManager(fileName, append, isImmediateFlush(),
                      actualRegionLength, advertiseURI, layout);
              if (manager == null) {
                  return null;
              }
  
              return new MemoryMappedFileAppender(name, layout, getFilter(), manager, fileName, isIgnoreExceptions(), false,
                      advertise ? getConfiguration().getAdvertiser() : null);
          }
  
          public B setFileName(final String fileName) {
              this.fileName = fileName;
              return asBuilder();
          }
  
          public B setAppend(final boolean append) {
             this.append = append;
             return asBuilder();
         }
 
         public B setRegionLength(final int regionLength) {
             this.regionLength = regionLength;
             return asBuilder();
         }
 
         public B setAdvertise(final boolean advertise) {
             this.advertise = advertise;
             return asBuilder();
         }
 
         public B setAdvertiseURI(final String advertiseURI) {
             this.advertiseURI = advertiseURI;
             return asBuilder();
         }
 
     }
     
     private static final int BIT_POSITION_1GB = 30; // 2^30 ~= 1GB
     private static final int MAX_REGION_LENGTH = 1 << BIT_POSITION_1GB;
     private static final int MIN_REGION_LENGTH = 256;
 
     private final String fileName;
     private Object advertisement;
     private final Advertiser advertiser;
 
     private MemoryMappedFileAppender(final String name, final Layout<? extends Serializable> layout,
             final Filter filter, final MemoryMappedFileManager manager, final String filename,
             final boolean ignoreExceptions, final boolean immediateFlush, final Advertiser advertiser) {
         super(name, layout, filter, ignoreExceptions, immediateFlush, manager);
         if (advertiser != null) {
             final Map<String, String> configuration = new HashMap<>(layout.getContentFormat());
             configuration.putAll(manager.getContentFormat());
             configuration.put("contentType", layout.getContentType());
             configuration.put("name", name);
             advertisement = advertiser.advertise(configuration);
         }
         this.fileName = filename;
         this.advertiser = advertiser;
     }
 
     @Override
     public boolean stop(final long timeout, final TimeUnit timeUnit) {
         setStopping();
         super.stop(timeout, timeUnit, false);
         if (advertiser != null) {
             advertiser.unadvertise(advertisement);
         }
         setStopped();
         return true;
     }
 
     /**
      * Write the log entry rolling over the file when required.
      *
      * @param event The LogEvent.
      */
     @Override
     public void append(final LogEvent event) {
 
         // Leverage the nice batching behaviour of async Loggers/Appenders:
         // we can signal the file manager that it needs to flush the buffer
         // to disk at the end of a batch.
         // From a user's point of view, this means that all log events are
         // _always_ available in the log file, without incurring the overhead
         // of immediateFlush=true.
         getManager().setEndOfBatch(event.isEndOfBatch()); // FIXME manager's EndOfBatch threadlocal can be deleted
         super.append(event); // TODO should only call force() if immediateFlush && endOfBatch?
     }
 
     /**
      * Returns the file name this appender is associated with.
      *
      * @return The File name.
      */
     public String getFileName() {
         return this.fileName;
     }
 
     /**
      * Returns the length of the memory mapped region.
      *
      * @return the length of the memory mapped region
      */
     public int getRegionLength() {
         return getManager().getRegionLength();
     }
 
     /**
      * Create a Memory Mapped File Appender.
      *
      * @param fileName The name and path of the file.
      * @param append "True" if the file should be appended to, "false" if it should be overwritten. The default is
      *            "true".
      * @param name The name of the Appender.
      * @param immediateFlush "true" if the contents should be flushed on every write, "false" otherwise. The default is
      *            "false".
      * @param regionLengthStr The buffer size, defaults to {@value MemoryMappedFileManager#DEFAULT_REGION_LENGTH}.
      * @param ignore If {@code "true"} (default) exceptions encountered when appending events are logged; otherwise they
      *            are propagated to the caller.
      * @param layout The layout to use to format the event. If no layout is provided the default PatternLayout will be
      *            used.
      * @param filter The filter, if any, to use.
      * @param advertise "true" if the appender configuration should be advertised, "false" otherwise.
      * @param advertiseURI The advertised URI which can be used to retrieve the file contents.
      * @param config The Configuration.
      * @return The FileAppender.
      * @deprecated Use {@link #newBuilder()}.
      */
     @Deprecated
     public static <B extends Builder<B>> MemoryMappedFileAppender createAppender(
             // @formatter:off
             final String fileName, //
             final String append, //
             final String name, //
             final String immediateFlush, //
             final String regionLengthStr, //
             final String ignore, //
             final Layout<? extends Serializable> layout, //
             final Filter filter, //
             final String advertise, //
             final String advertiseURI, //
             final Configuration config) {
             // @formatter:on
 
         final boolean isAppend = Booleans.parseBoolean(append, true);
         final boolean isImmediateFlush = Booleans.parseBoolean(immediateFlush, false);
         final boolean ignoreExceptions = Booleans.parseBoolean(ignore, true);
         final boolean isAdvertise = Boolean.parseBoolean(advertise);
         final int regionLength = Integers.parseInt(regionLengthStr, MemoryMappedFileManager.DEFAULT_REGION_LENGTH);
 
         // @formatter:off
         return MemoryMappedFileAppender.<B>newBuilder()
             .setAdvertise(isAdvertise)
             .setAdvertiseURI(advertiseURI)
             .setAppend(isAppend)
             .setConfiguration(config)
             .setFileName(fileName)
             .withFilter(filter)
             .withIgnoreExceptions(ignoreExceptions)
             .withImmediateFlush(isImmediateFlush)
             .withLayout(layout)
             .withName(name)
             .setRegionLength(regionLength)
             .build();
         // @formatter:on
     }
 
     @PluginBuilderFactory
     public static <B extends Builder<B>> B newBuilder() {
         return new Builder<B>().asBuilder();
     }
 
     /**
      * Converts the specified region length to a valid value.
      */
     private static int determineValidRegionLength(final String name, final int regionLength) {
         if (regionLength > MAX_REGION_LENGTH) {
             LOGGER.info("MemoryMappedAppender[{}] Reduced region length from {} to max length: {}", name, regionLength,
                     MAX_REGION_LENGTH);
             return MAX_REGION_LENGTH;
         }
         if (regionLength < MIN_REGION_LENGTH) {
             LOGGER.info("MemoryMappedAppender[{}] Expanded region length from {} to min length: {}", name, regionLength,
                     MIN_REGION_LENGTH);
             return MIN_REGION_LENGTH;
         }
         final int result = Integers.ceilingNextPowerOfTwo(regionLength);
         if (regionLength != result) {
             LOGGER.info("MemoryMappedAppender[{}] Rounded up region length from {} to next power of two: {}", name,
                     regionLength, result);
         }
         return result;
     }
 }