/*
    * 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.maven.lifecycle.internal.concurrent;
  
  import java.util.List;
  import java.util.concurrent.CopyOnWriteArrayList;
  
  import org.apache.maven.project.MavenProject;
  import org.apache.maven.slf4j.MavenSimpleLogger;
  
  /**
   * Forwards log messages to the client.
   */
  public class ConcurrentLogOutput implements AutoCloseable {
  
      private static final ThreadLocal<ProjectExecutionContext> CONTEXT = new InheritableThreadLocal<>();
  
      public ConcurrentLogOutput() {
          MavenSimpleLogger.setLogSink(this::accept);
      }
  
      protected void accept(String message) {
          ProjectExecutionContext context = CONTEXT.get();
          if (context != null) {
              context.accept(message);
          } else {
              System.out.println(message);
          }
      }
  
      @Override
      public void close() {
          MavenSimpleLogger.setLogSink(null);
      }
  
      public AutoCloseable build(MavenProject project) {
          return new ProjectExecutionContext(project);
      }
  
      private static class ProjectExecutionContext implements AutoCloseable {
          final MavenProject project;
          final List<String> messages = new CopyOnWriteArrayList<>();
          boolean closed;
  
          ProjectExecutionContext(MavenProject project) {
              this.project = project;
              CONTEXT.set(this);
          }
  
          void accept(String message) {
              if (!closed) {
                  this.messages.add(message);
              } else {
                  System.out.println(message);
              }
          }
  
          @Override
          public void close() {
              closed = true;
              CONTEXT.set(null);
              this.messages.forEach(System.out::println);
          }
      }
  }