/*
    * 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.FileDescriptor;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.io.PrintStream;
  import java.io.Serializable;
  import java.io.UnsupportedEncodingException;
  import java.lang.reflect.Constructor;
  import java.nio.charset.Charset;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.logging.log4j.core.Appender;
  import org.apache.logging.log4j.core.Filter;
  import org.apache.logging.log4j.core.Layout;
  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.validation.constraints.Required;
  import org.apache.logging.log4j.core.layout.PatternLayout;
  import org.apache.logging.log4j.core.util.Booleans;
  import org.apache.logging.log4j.core.util.CloseShieldOutputStream;
  import org.apache.logging.log4j.util.LoaderUtil;
  import org.apache.logging.log4j.util.PropertiesUtil;
  
  /**
   * Appends log events to <code>System.out</code> or <code>System.err</code> using a layout specified by the user. The
   * default target is <code>System.out</code>.
   * <p>
   * TODO accessing System.out or .err as a byte stream instead of a writer bypasses the JVM's knowledge of the proper
   * encoding. (RG) Encoding is handled within the Layout. Typically, a Layout will generate a String and then call
   * getBytes which may use a configured encoding or the system default. OTOH, a Writer cannot print byte streams.
   */
  @Plugin(name = ConsoleAppender.PLUGIN_NAME, category = "Core", elementType = Appender.ELEMENT_TYPE, printObject = true)
  public final class ConsoleAppender extends AbstractOutputStreamAppender<OutputStreamManager> {
  
      public static final String PLUGIN_NAME = "Console";
      private static final String JANSI_CLASS = "org.fusesource.jansi.WindowsAnsiOutputStream";
      private static ConsoleManagerFactory factory = new ConsoleManagerFactory();
      private static final Target DEFAULT_TARGET = Target.SYSTEM_OUT;
      private static final AtomicInteger COUNT = new AtomicInteger();
  
      private final Target target;
  
      /**
       * Enumeration of console destinations.
       */
      public enum Target {
          /** Standard output. */
          SYSTEM_OUT,
          /** Standard error output. */
          SYSTEM_ERR
      }
  
      private ConsoleAppender(final String name, final Layout<? extends Serializable> layout, final Filter filter,
              final OutputStreamManager manager, final boolean ignoreExceptions, final Target target) {
          super(name, layout, filter, ignoreExceptions, true, manager);
          this.target = target;
      }
  
      /**
       * Creates a Console Appender.
       *
       * @param layout The layout to use (required).
       * @param filter The Filter or null.
       * @param targetStr The target ("SYSTEM_OUT" or "SYSTEM_ERR"). The default is "SYSTEM_OUT".
       * @param name The name of the Appender (required).
       * @param follow If true will follow changes to the underlying output stream.
       * @param ignore If {@code "true"} (default) exceptions encountered when appending events are logged; otherwise they
       *            are propagated to the caller.
       * @return The ConsoleAppender.
       * @deprecated Deprecated in 2.7; use {@link #newBuilder()}.
       */
      @Deprecated
      public static ConsoleAppender createAppender(Layout<? extends Serializable> layout,
              final Filter filter,
              final String targetStr,
              final String name,
              final String follow,
              final String ignore) {
          if (name == null) {
              LOGGER.error("No name provided for ConsoleAppender");
             return null;
         }
         if (layout == null) {
             layout = PatternLayout.createDefaultLayout();
         }
         final boolean isFollow = Boolean.parseBoolean(follow);
         final boolean ignoreExceptions = Booleans.parseBoolean(ignore, true);
         final Target target = targetStr == null ? DEFAULT_TARGET : Target.valueOf(targetStr);
         return new ConsoleAppender(name, layout, filter, getManager(target, isFollow, false, layout), ignoreExceptions, target);
     }
 
     /**
      * Creates a Console Appender.
      *
      * @param layout The layout to use (required).
      * @param filter The Filter or null.
      * @param target The target (SYSTEM_OUT or SYSTEM_ERR). The default is SYSTEM_OUT.
      * @param name The name of the Appender (required).
      * @param follow If true will follow changes to the underlying output stream.
      * @param direct If true will write directly to {@link java.io.FileDescriptor} and bypass
      *            {@link System#out}/{@link System#err}.
      * @param ignoreExceptions If {@code "true"} (default) exceptions encountered when appending events are logged; otherwise they
      *            are propagated to the caller.
      * @return The ConsoleAppender.
      * @deprecated Deprecated in 2.7; use {@link #newBuilder()}.
      */
     @Deprecated
     public static ConsoleAppender createAppender(
             // @formatter:off
             Layout<? extends Serializable> layout,
             final Filter filter,
             Target target,
             final String name,
             final boolean follow,
             final boolean direct,
             final boolean ignoreExceptions) {
             // @formatter:on
         if (name == null) {
             LOGGER.error("No name provided for ConsoleAppender");
             return null;
         }
         if (layout == null) {
             layout = PatternLayout.createDefaultLayout();
         }
         target = target == null ? Target.SYSTEM_OUT : target;
         if (follow && direct) {
             LOGGER.error("Cannot use both follow and direct on ConsoleAppender");
             return null;
         }
         return new ConsoleAppender(name, layout, filter, getManager(target, follow, direct, layout), ignoreExceptions, target);
     }
 
     public static ConsoleAppender createDefaultAppenderForLayout(final Layout<? extends Serializable> layout) {
         // this method cannot use the builder class without introducing an infinite loop due to DefaultConfiguration
         return new ConsoleAppender("DefaultConsole-" + COUNT.incrementAndGet(), layout, null,
                 getDefaultManager(DEFAULT_TARGET, false, false, layout), true, DEFAULT_TARGET);
     }
 
     @PluginBuilderFactory
     public static <B extends Builder<B>> B newBuilder() {
         return new Builder<B>().asBuilder();
     }
 
     /**
      * Builds ConsoleAppender instances.
      * @param <B> This builder class
      */
     public static class Builder<B extends Builder<B>> extends AbstractOutputStreamAppender.Builder<B>
             implements org.apache.logging.log4j.core.util.Builder<ConsoleAppender> {
 
         @PluginBuilderAttribute
         @Required
         private Target target = DEFAULT_TARGET;
 
         @PluginBuilderAttribute
         private boolean follow;
 
         @PluginBuilderAttribute
         private boolean direct;
 
         public B setTarget(final Target aTarget) {
             this.target = aTarget;
             return asBuilder();
         }
 
         public B setFollow(final boolean shouldFollow) {
             this.follow = shouldFollow;
             return asBuilder();
         }
 
         public B setDirect(final boolean shouldDirect) {
             this.direct = shouldDirect;
             return asBuilder();
         }
 
         @Override
         public ConsoleAppender build() {
             if (follow && direct) {
                 throw new IllegalArgumentException("Cannot use both follow and direct on ConsoleAppender '" + getName() + "'");
             }
             final Layout<? extends Serializable> layout = getOrCreateLayout();
             return new ConsoleAppender(getName(), layout, getFilter(), getManager(target, follow, direct, layout),
                     isIgnoreExceptions(), target);
         }
     }
 
     private static OutputStreamManager getDefaultManager(final Target target, final boolean follow, final boolean direct,
             final Layout<? extends Serializable> layout) {
         final OutputStream os = getOutputStream(follow, direct, target);
 
         // LOG4J2-1176 DefaultConfiguration should not share OutputStreamManager instances to avoid memory leaks.
         final String managerName = target.name() + '.' + follow + '.' + direct + "-" + COUNT.get();
         return OutputStreamManager.getManager(managerName, new FactoryData(os, managerName, layout), factory);
     }
 
     private static OutputStreamManager getManager(final Target target, final boolean follow, final boolean direct,
             final Layout<? extends Serializable> layout) {
         final OutputStream os = getOutputStream(follow, direct, target);
         final String managerName = target.name() + '.' + follow + '.' + direct;
         return OutputStreamManager.getManager(managerName, new FactoryData(os, managerName, layout), factory);
     }
 
     private static OutputStream getOutputStream(final boolean follow, final boolean direct, final Target target) {
         final String enc = Charset.defaultCharset().name();
         OutputStream outputStream;
         try {
             // @formatter:off
             outputStream = target == Target.SYSTEM_OUT ?
                 direct ? new FileOutputStream(FileDescriptor.out) :
                     (follow ? new PrintStream(new SystemOutStream(), true, enc) : System.out) :
                 direct ? new FileOutputStream(FileDescriptor.err) :
                     (follow ? new PrintStream(new SystemErrStream(), true, enc) : System.err);
             // @formatter:on
             outputStream = new CloseShieldOutputStream(outputStream);
         } catch (final UnsupportedEncodingException ex) { // should never happen
             throw new IllegalStateException("Unsupported default encoding " + enc, ex);
         }
         final PropertiesUtil propsUtil = PropertiesUtil.getProperties();
         if (!propsUtil.isOsWindows() || propsUtil.getBooleanProperty("log4j.skipJansi") || direct) {
             return outputStream;
         }
         try {
             // We type the parameter as a wildcard to avoid a hard reference to Jansi.
             final Class<?> clazz = LoaderUtil.loadClass(JANSI_CLASS);
             final Constructor<?> constructor = clazz.getConstructor(OutputStream.class);
             return new CloseShieldOutputStream((OutputStream) constructor.newInstance(outputStream));
         } catch (final ClassNotFoundException cnfe) {
             LOGGER.debug("Jansi is not installed, cannot find {}", JANSI_CLASS);
         } catch (final NoSuchMethodException nsme) {
             LOGGER.warn("{} is missing the proper constructor", JANSI_CLASS);
         } catch (final Exception ex) {
             LOGGER.warn("Unable to instantiate {}", JANSI_CLASS);
         }
         return outputStream;
     }
 
     /**
      * An implementation of OutputStream that redirects to the current System.err.
      */
     private static class SystemErrStream extends OutputStream {
         public SystemErrStream() {
         }
 
         @Override
         public void close() {
             // do not close sys err!
         }
 
         @Override
         public void flush() {
             System.err.flush();
         }
 
         @Override
         public void write(final byte[] b) throws IOException {
             System.err.write(b);
         }
 
         @Override
         public void write(final byte[] b, final int off, final int len) throws IOException {
             System.err.write(b, off, len);
         }
 
         @Override
         public void write(final int b) {
             System.err.write(b);
         }
     }
 
     /**
      * An implementation of OutputStream that redirects to the current System.out.
      */
     private static class SystemOutStream extends OutputStream {
         public SystemOutStream() {
         }
 
         @Override
         public void close() {
             // do not close sys out!
         }
 
         @Override
         public void flush() {
             System.out.flush();
         }
 
         @Override
         public void write(final byte[] b) throws IOException {
             System.out.write(b);
         }
 
         @Override
         public void write(final byte[] b, final int off, final int len) throws IOException {
             System.out.write(b, off, len);
         }
 
         @Override
         public void write(final int b) throws IOException {
             System.out.write(b);
         }
     }
 
     /**
      * Data to pass to factory method.
      */
     private static class FactoryData {
         private final OutputStream os;
         private final String name;
         private final Layout<? extends Serializable> layout;
 
         /**
          * Constructor.
          *
          * @param os The OutputStream.
          * @param type The name of the target.
          * @param layout A Serializable layout
          */
         public FactoryData(final OutputStream os, final String type, final Layout<? extends Serializable> layout) {
             this.os = os;
             this.name = type;
             this.layout = layout;
         }
     }
 
     /**
      * Factory to create the Appender.
      */
     private static class ConsoleManagerFactory implements ManagerFactory<OutputStreamManager, FactoryData> {
 
         /**
          * Create an OutputStreamManager.
          *
          * @param name The name of the entity to manage.
          * @param data The data required to create the entity.
          * @return The OutputStreamManager
          */
         @Override
         public OutputStreamManager createManager(final String name, final FactoryData data) {
             return new OutputStreamManager(data.os, data.name, data.layout, true);
         }
     }
 
     public Target getTarget() {
         return target;
     }
 
 }