/*
    * 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.eclipse.aether.internal.impl;
  
  import javax.inject.Inject;
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.util.ArrayList;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.CopyOnWriteArrayList;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.eclipse.aether.MultiRuntimeException;
  import org.eclipse.aether.RepositorySystemSession.CloseableSession;
  import org.eclipse.aether.impl.RepositorySystemLifecycle;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   *
   */
  @Singleton
  @Named
  public class DefaultRepositorySystemLifecycle implements RepositorySystemLifecycle {
      private final AtomicBoolean shutdown;
  
      private final CopyOnWriteArrayList<Runnable> onSystemEndedHandlers;
  
      private final ConcurrentHashMap<String, CopyOnWriteArrayList<Runnable>> onSessionEndedHandlers;
  
      @Inject
      public DefaultRepositorySystemLifecycle() {
          this.shutdown = new AtomicBoolean(false);
          this.onSystemEndedHandlers = new CopyOnWriteArrayList<>();
          this.onSessionEndedHandlers = new ConcurrentHashMap<>();
      }
  
      @Override
      public void systemEnded() {
          final ArrayList<Exception> exceptions = new ArrayList<>();
          if (shutdown.compareAndSet(false, true)) {
              for (Map.Entry<String, CopyOnWriteArrayList<Runnable>> sessionEndedHandlers :
                      onSessionEndedHandlers.entrySet()) {
                  IllegalStateException sessionNotClosed =
                          new IllegalStateException("Session " + sessionEndedHandlers.getKey() + " not closed");
                  exceptions.add(sessionNotClosed);
                  for (Runnable onCloseHandler : sessionEndedHandlers.getValue()) {
                      try {
                          onCloseHandler.run();
                      } catch (Exception e) {
                          sessionNotClosed.addSuppressed(e);
                      }
                  }
              }
              for (Runnable onCloseHandler : onSystemEndedHandlers) {
                  try {
                      onCloseHandler.run();
                  } catch (Exception e) {
                      exceptions.add(e);
                  }
              }
              MultiRuntimeException.mayThrow("system on-close handler failures", exceptions);
          }
      }
  
      @Override
      public void addOnSystemEndedHandler(Runnable handler) {
          requireNonNull(handler, "handler cannot be null");
          requireNotShutdown();
          onSystemEndedHandlers.add(0, handler);
      }
  
      @Override
      public void sessionStarted(CloseableSession session) {
          requireNonNull(session, "session cannot be null");
          requireNotShutdown();
          String sessionId = session.sessionId();
          onSessionEndedHandlers.compute(sessionId, (k, v) -> {
              if (v != null) {
                  throw new IllegalStateException("session instance already registered");
              }
             return new CopyOnWriteArrayList<>();
         });
     }
 
     @Override
     public void sessionEnded(CloseableSession session) {
         requireNonNull(session, "session cannot be null");
         requireNotShutdown();
         String sessionId = session.sessionId();
         ArrayList<Runnable> handlers = new ArrayList<>();
         onSessionEndedHandlers.compute(sessionId, (k, v) -> {
             if (v == null) {
                 throw new IllegalStateException("session instance not registered");
             }
             handlers.addAll(v);
             return null;
         });
 
         ArrayList<Exception> exceptions = new ArrayList<>();
         for (Runnable handler : handlers) {
             try {
                 handler.run();
             } catch (Exception e) {
                 exceptions.add(e);
             }
         }
         MultiRuntimeException.mayThrow("sessionEnded handler issue(s)", exceptions);
     }
 
     @Override
     public void addOnSessionEndedHandle(CloseableSession session, Runnable handler) {
         requireNonNull(session, "session cannot be null");
         requireNonNull(handler, "handler cannot be null");
         requireNotShutdown();
         String sessionId = session.sessionId();
         onSessionEndedHandlers.compute(sessionId, (k, v) -> {
             if (v == null) {
                 throw new IllegalStateException("session instance not registered");
             }
             v.add(handler);
             return v;
         });
     }
 
     private void requireNotShutdown() {
         if (shutdown.get()) {
             throw new IllegalStateException("repository system is already shut down");
         }
     }
 }