/*
    * 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.named.hazelcast;
  
  import java.nio.file.Files;
  import java.nio.file.Paths;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ConcurrentMap;
  import java.util.concurrent.TimeUnit;
  
  import com.hazelcast.core.HazelcastInstance;
  import com.hazelcast.cp.ISemaphore;
  import org.eclipse.aether.named.NamedLock;
  import org.eclipse.aether.named.NamedLockKey;
  import org.eclipse.aether.named.support.AdaptedSemaphoreNamedLock;
  import org.eclipse.aether.named.support.AdaptedSemaphoreNamedLock.AdaptedSemaphore;
  import org.eclipse.aether.named.support.NamedLockFactorySupport;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Factory of {@link AdaptedSemaphoreNamedLock} instances, using adapted Hazelcast {@link ISemaphore}. It delegates
   * most the work to {@link HazelcastSemaphoreProvider} and this class just adapts the returned semaphore to named lock
   * and caches {@link ISemaphore} instances, as recommended by Hazelcast.
   *
   * @deprecated Hazelcast support will be dropped.
   */
  @Deprecated
  public class HazelcastSemaphoreNamedLockFactory extends NamedLockFactorySupport {
      protected final HazelcastInstance hazelcastInstance;
  
      protected final boolean manageHazelcast;
  
      private final HazelcastSemaphoreProvider hazelcastSemaphoreProvider;
  
      private final ConcurrentMap<NamedLockKey, ISemaphore> semaphores;
  
      public HazelcastSemaphoreNamedLockFactory(
              final HazelcastInstance hazelcastInstance,
              final boolean manageHazelcast,
              final HazelcastSemaphoreProvider hazelcastSemaphoreProvider) {
          this.hazelcastInstance = requireNonNull(hazelcastInstance);
          this.manageHazelcast = manageHazelcast;
          this.hazelcastSemaphoreProvider = requireNonNull(hazelcastSemaphoreProvider);
          this.semaphores = new ConcurrentHashMap<>();
      }
  
      /**
       * Guard used by the default constructors of subclasses before they create a Hazelcast member or client via
       * standard Hazelcast configuration discovery: refuses to proceed when no explicit operator-provided
       * configuration is discoverable. Without one, Hazelcast falls back to its built-in defaults (default cluster
       * name, auto-discovery join, no authentication or TLS in open-source Hazelcast), which lets any peer able to
       * reach the network segment join the cluster and release the semaphore permits that guard local repository
       * writes.
       *
       * @param configSystemProperty the Hazelcast system property naming an explicit configuration file
       * @param classLoader the class loader to probe for configuration resources
       * @param configResourceNames configuration file names probed on the classpath and in the working directory
       * @throws IllegalStateException if no explicit configuration is discoverable
       */
      static void requireExplicitHazelcastConfig(
              final String configSystemProperty, final ClassLoader classLoader, final String... configResourceNames) {
          if (System.getProperty(configSystemProperty) != null) {
              return;
          }
          for (String configResourceName : configResourceNames) {
              if (classLoader.getResource(configResourceName) != null
                      || Files.isRegularFile(Paths.get(configResourceName))) {
                  return;
              }
          }
          throw new IllegalStateException(
                  "Refusing to create a Hazelcast instance from built-in defaults (default cluster name,"
                          + " auto-discovery join, no authentication): distributed lock state guarding local"
                          + " repository writes would be modifiable by unauthenticated network peers. Provide an"
                          + " explicit Hazelcast configuration that secures or isolates the cluster, via the '"
                          + configSystemProperty + "' system property or one of "
                          + String.join(", ", configResourceNames)
                          + " on the classpath or in the working directory.");
      }
  
      @Override
      protected AdaptedSemaphoreNamedLock createLock(final NamedLockKey key) {
         ISemaphore semaphore = semaphores.computeIfAbsent(
                 key, k -> hazelcastSemaphoreProvider.acquireSemaphore(hazelcastInstance, key));
         return new AdaptedSemaphoreNamedLock(key, this, new HazelcastSemaphore(semaphore));
     }
 
     @Override
     protected void destroyLock(final NamedLock namedLock) {
         if (namedLock instanceof AdaptedSemaphoreNamedLock) {
             final NamedLockKey key = namedLock.key();
             hazelcastSemaphoreProvider.releaseSemaphore(hazelcastInstance, key, semaphores.remove(key));
         }
     }
 
     @Override
     protected void doShutdown() {
         if (manageHazelcast) {
             hazelcastInstance.shutdown();
         }
     }
 
     private static final class HazelcastSemaphore implements AdaptedSemaphore {
         private final ISemaphore semaphore;
 
         private HazelcastSemaphore(final ISemaphore semaphore) {
             this.semaphore = semaphore;
         }
 
         @Override
         public boolean tryAcquire(final int perms, final long time, final TimeUnit unit) throws InterruptedException {
             return semaphore.tryAcquire(perms, time, unit);
         }
 
         @Override
         public void release(final int perms) {
             semaphore.release(perms);
         }
     }
 }