/**
    * This file Copyright (c) 2019 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.context;
  
  import info.magnolia.cms.security.User;
  import info.magnolia.repository.RepositoryManager;
  
  import java.util.Locale;
  import java.util.concurrent.Callable;
  
  import javax.inject.Inject;
  import javax.inject.Provider;
  import javax.jcr.RepositoryException;
  import javax.jcr.Session;
  import javax.security.auth.Subject;
  
  import com.machinezoo.noexception.Exceptions;
  
  /**
   * Context usable when original web context might be already released.
   */
  public class AsynchronousContext extends AbstractContext {
  
      private final User user;
      private final Subject subject;
      private final Locale locale;
  
      AsynchronousContext(RepositoryManager repositoryManager, Context originalContext) {
          setAttributeStrategy(new MapAttributeStrategy());
          setRepositoryStrategy(new DefaultRepositoryStrategy(repositoryManager, null));
          user = originalContext.getUser();
          subject = originalContext.getSubject();
          locale = originalContext.getLocale();
      }
  
      @Override
      public Session getJCRSession(String workspaceName) throws RepositoryException {
          return getRepositoryStrategy().getSession(workspaceName);
      }
  
      @Override
      public void release() {
          getRepositoryStrategy().release();
      }
  
      @Override
      public Locale getLocale() {
          return locale;
      }
  
      @Override
      public User getUser() {
          return user;
      }
  
      @Override
      public Subject getSubject() {
          return subject;
      }
  
      /**
       * Wraps {@link java.util.concurrent.Callable} so it can be executed in asynchronous context.
       * This operation has to be called in a separate thread.
       */
      public static class OperationFactory {
  
          private final Provider<SystemContext> systemContextProvider;
          private final RepositoryManager repositoryManager;
         private final Context originalContext;
 
         @Inject
         public OperationFactory(RepositoryManager repositoryManager, Context originalContext, Provider<SystemContext> systemContextProvider) {
             this.repositoryManager = repositoryManager;
             this.systemContextProvider = systemContextProvider;
             this.originalContext = originalContext;
         }
 
         /**
          * @param operation operation to be executed asynchronously
          * @throws java.lang.IllegalStateException if {@link info.magnolia.context.MgnlContext} is already set for this thread.
          * @return result of the operation. Don't return JCR objects as their asynchronously created session is already released.
          */
         public <T> Callable<T> wrap(Callable<T> operation) {
             return () -> {
                 if (MgnlContext.hasInstance()) {
                     throw new IllegalStateException("MgnlContext is already set for this thread. Please run result of info.magnolia.context.AsynchronousContext.OperationFactory#wrap in a separate thread");
                 }
                 final AsynchronousContextl#AsynchronousContext">AsynchronousContext context = new AsynchronousContext(repositoryManager, originalContext); //new instance as there could be more parallel threads
                 MgnlContext.setInstance(context);
                 try {
                     return operation.call();
                 } finally {
                     systemContextProvider.get().release(); //operation might use system context which is created for thread, we need to release JCR session from this context as well, see info.magnolia.context.JCRSessionPerThreadSystemContext.getRepositoryStrategy
                     context.release();
                     MgnlContext.setInstance(null);
                 }
             };
         }
 
         public Runnable wrap(Runnable operation) {
             return Exceptions.wrap().runnable(() -> wrap(() -> {
                 operation.run();
                 return null;
             }).call());
         }
     }
 }