/*
    * 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.impl;
  
  import java.lang.reflect.Constructor;
  import java.lang.reflect.Modifier;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.LinkedHashSet;
  import java.util.List;
  import java.util.Map;
  
  import org.eclipse.aether.RepositorySystem;
  import org.eclipse.aether.internal.impl.DefaultArtifactResolver;
  import org.eclipse.aether.internal.impl.DefaultChecksumPolicyProvider;
  import org.eclipse.aether.internal.impl.DefaultDeployer;
  import org.eclipse.aether.internal.impl.DefaultFileProcessor;
  import org.eclipse.aether.internal.impl.DefaultInstaller;
  import org.eclipse.aether.internal.impl.DefaultLocalPathComposer;
  import org.eclipse.aether.internal.impl.DefaultLocalRepositoryProvider;
  import org.eclipse.aether.internal.impl.DefaultMetadataResolver;
  import org.eclipse.aether.internal.impl.DefaultOfflineController;
  import org.eclipse.aether.internal.impl.DefaultRemoteRepositoryManager;
  import org.eclipse.aether.internal.impl.DefaultRepositoryConnectorProvider;
  import org.eclipse.aether.internal.impl.DefaultRepositoryEventDispatcher;
  import org.eclipse.aether.internal.impl.DefaultRepositoryLayoutProvider;
  import org.eclipse.aether.internal.impl.DefaultRepositorySystem;
  import org.eclipse.aether.internal.impl.DefaultRepositorySystemLifecycle;
  import org.eclipse.aether.internal.impl.DefaultTrackingFileManager;
  import org.eclipse.aether.internal.impl.DefaultTransporterProvider;
  import org.eclipse.aether.internal.impl.DefaultUpdateCheckManager;
  import org.eclipse.aether.internal.impl.DefaultUpdatePolicyAnalyzer;
  import org.eclipse.aether.internal.impl.EnhancedLocalRepositoryManagerFactory;
  import org.eclipse.aether.internal.impl.LocalPathComposer;
  import org.eclipse.aether.internal.impl.Maven2RepositoryLayoutFactory;
  import org.eclipse.aether.internal.impl.SimpleLocalRepositoryManagerFactory;
  import org.eclipse.aether.internal.impl.TrackingFileManager;
  import org.eclipse.aether.internal.impl.checksum.DefaultChecksumAlgorithmFactorySelector;
  import org.eclipse.aether.internal.impl.collect.DefaultDependencyCollector;
  import org.eclipse.aether.internal.impl.filter.DefaultRemoteRepositoryFilterManager;
  import org.eclipse.aether.internal.impl.slf4j.Slf4jLoggerFactory;
  import org.eclipse.aether.internal.impl.synccontext.DefaultSyncContextFactory;
  import org.eclipse.aether.internal.impl.synccontext.named.NamedLockFactoryAdapterFactory;
  import org.eclipse.aether.internal.impl.synccontext.named.NamedLockFactoryAdapterFactoryImpl;
  import org.eclipse.aether.spi.connector.checksum.ChecksumAlgorithmFactorySelector;
  import org.eclipse.aether.spi.connector.checksum.ChecksumPolicyProvider;
  import org.eclipse.aether.spi.connector.layout.RepositoryLayoutFactory;
  import org.eclipse.aether.spi.connector.layout.RepositoryLayoutProvider;
  import org.eclipse.aether.spi.connector.transport.TransporterProvider;
  import org.eclipse.aether.spi.io.FileProcessor;
  import org.eclipse.aether.spi.localrepo.LocalRepositoryManagerFactory;
  import org.eclipse.aether.spi.locator.Service;
  import org.eclipse.aether.spi.locator.ServiceLocator;
  import org.eclipse.aether.spi.log.LoggerFactory;
  import org.eclipse.aether.spi.synccontext.SyncContextFactory;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A simple service locator that is already setup with all components from this library. To acquire a complete
   * repository system, clients need to add an artifact descriptor reader, a version resolver, a version range resolver
   * and optionally some repository connector and transporter factories to access remote repositories. Once the locator is
   * fully populated, the repository system can be created like this:
   *
   * <pre>
   * RepositorySystem repoSystem = serviceLocator.getService( RepositorySystem.class );
   * </pre>
   *
   * <em>Note:</em> This class is not thread-safe. Clients are expected to create the service locator and the repository
   * system on a single thread.
   *
   * @deprecated Use some out-of-the-box DI implementation instead.
   */
  @Deprecated
  public final class DefaultServiceLocator implements ServiceLocator {
  
      private class Entry<T> {
  
          private final Class<T> type;
  
          private final Collection<Object> providers;
 
         private List<T> instances;
 
         Entry(Class<T> type) {
             this.type = requireNonNull(type, "service type cannot be null");
             providers = new LinkedHashSet<>(8);
         }
 
         public synchronized void setServices(T... services) {
             providers.clear();
             if (services != null) {
                 for (T service : services) {
                     providers.add(requireNonNull(service, "service instance cannot be null"));
                 }
             }
             instances = null;
         }
 
         public synchronized void setService(Class<? extends T> impl) {
             providers.clear();
             addService(impl);
         }
 
         public synchronized void addService(Class<? extends T> impl) {
             providers.add(requireNonNull(impl, "implementation class cannot be null"));
             instances = null;
         }
 
         public T getInstance() {
             List<T> instances = getInstances();
             return instances.isEmpty() ? null : instances.get(0);
         }
 
         public synchronized List<T> getInstances() {
             if (instances == null) {
                 instances = new ArrayList<>(providers.size());
                 for (Object provider : providers) {
                     T instance;
                     if (provider instanceof Class) {
                         instance = newInstance((Class<?>) provider);
                     } else {
                         instance = type.cast(provider);
                     }
                     if (instance != null) {
                         instances.add(instance);
                     }
                 }
                 instances = Collections.unmodifiableList(instances);
             }
             return instances;
         }
 
         private T newInstance(Class<?> impl) {
             try {
                 Constructor<?> constr = impl.getDeclaredConstructor();
                 if (!Modifier.isPublic(constr.getModifiers())) {
                     constr.setAccessible(true);
                 }
                 Object obj = constr.newInstance();
 
                 T instance = type.cast(obj);
                 if (instance instanceof Service) {
                     ((Service) instance).initService(DefaultServiceLocator.this);
                 }
                 return instance;
             } catch (Exception | LinkageError e) {
                 serviceCreationFailed(type, impl, e);
             }
             return null;
         }
     }
 
     private final Map<Class<?>, Entry<?>> entries;
 
     private ErrorHandler errorHandler;
 
     /**
      * Creates a new service locator that already knows about all service implementations included this library.
      */
     public DefaultServiceLocator() {
         entries = new HashMap<>();
 
         addService(RepositorySystem.class, DefaultRepositorySystem.class);
         addService(ArtifactResolver.class, DefaultArtifactResolver.class);
         addService(DependencyCollector.class, DefaultDependencyCollector.class);
         addService(Deployer.class, DefaultDeployer.class);
         addService(Installer.class, DefaultInstaller.class);
         addService(MetadataResolver.class, DefaultMetadataResolver.class);
         addService(RepositoryLayoutProvider.class, DefaultRepositoryLayoutProvider.class);
         addService(RepositoryLayoutFactory.class, Maven2RepositoryLayoutFactory.class);
         addService(TransporterProvider.class, DefaultTransporterProvider.class);
         addService(ChecksumPolicyProvider.class, DefaultChecksumPolicyProvider.class);
         addService(RepositoryConnectorProvider.class, DefaultRepositoryConnectorProvider.class);
         addService(RemoteRepositoryManager.class, DefaultRemoteRepositoryManager.class);
         addService(UpdateCheckManager.class, DefaultUpdateCheckManager.class);
         addService(UpdatePolicyAnalyzer.class, DefaultUpdatePolicyAnalyzer.class);
         addService(FileProcessor.class, DefaultFileProcessor.class);
         addService(
                 org.eclipse.aether.impl.SyncContextFactory.class,
                 org.eclipse.aether.internal.impl.synccontext.legacy.DefaultSyncContextFactory.class);
         addService(SyncContextFactory.class, DefaultSyncContextFactory.class);
         addService(RepositoryEventDispatcher.class, DefaultRepositoryEventDispatcher.class);
         addService(OfflineController.class, DefaultOfflineController.class);
         addService(LocalRepositoryProvider.class, DefaultLocalRepositoryProvider.class);
         addService(LocalRepositoryManagerFactory.class, SimpleLocalRepositoryManagerFactory.class);
         addService(LocalRepositoryManagerFactory.class, EnhancedLocalRepositoryManagerFactory.class);
         addService(LoggerFactory.class, Slf4jLoggerFactory.class);
         addService(TrackingFileManager.class, DefaultTrackingFileManager.class);
         addService(ChecksumAlgorithmFactorySelector.class, DefaultChecksumAlgorithmFactorySelector.class);
         addService(LocalPathComposer.class, DefaultLocalPathComposer.class);
         addService(RemoteRepositoryFilterManager.class, DefaultRemoteRepositoryFilterManager.class);
         addService(RepositorySystemLifecycle.class, DefaultRepositorySystemLifecycle.class);
         addService(NamedLockFactoryAdapterFactory.class, NamedLockFactoryAdapterFactoryImpl.class);
     }
 
     private <T> Entry<T> getEntry(Class<T> type, boolean create) {
         @SuppressWarnings("unchecked")
         Entry<T> entry = (Entry<T>) entries.get(requireNonNull(type, "service type cannot be null"));
         if (entry == null && create) {
             entry = new Entry<>(type);
             entries.put(type, entry);
         }
         return entry;
     }
 
     /**
      * Sets the implementation class for a service. The specified class must have a no-arg constructor (of any
      * visibility). If the service implementation itself requires other services for its operation, it should implement
      * {@link Service} to gain access to this service locator.
      *
      * @param <T> The service type.
      * @param type The interface describing the service, must not be {@code null}.
      * @param impl The implementation class of the service, must not be {@code null}.
      * @return This locator for chaining, never {@code null}.
      */
     public <T> DefaultServiceLocator setService(Class<T> type, Class<? extends T> impl) {
         getEntry(type, true).setService(impl);
         return this;
     }
 
     /**
      * Adds an implementation class for a service. The specified class must have a no-arg constructor (of any
      * visibility). If the service implementation itself requires other services for its operation, it should implement
      * {@link Service} to gain access to this service locator.
      *
      * @param <T> The service type.
      * @param type The interface describing the service, must not be {@code null}.
      * @param impl The implementation class of the service, must not be {@code null}.
      * @return This locator for chaining, never {@code null}.
      */
     public <T> DefaultServiceLocator addService(Class<T> type, Class<? extends T> impl) {
         getEntry(type, true).addService(impl);
         return this;
     }
 
     /**
      * Sets the instances for a service.
      *
      * @param <T> The service type.
      * @param type The interface describing the service, must not be {@code null}.
      * @param services The instances of the service, may be {@code null} but must not contain {@code null} elements.
      * @return This locator for chaining, never {@code null}.
      */
     public <T> DefaultServiceLocator setServices(Class<T> type, T... services) {
         getEntry(type, true).setServices(services);
         return this;
     }
 
     public <T> T getService(Class<T> type) {
         Entry<T> entry = getEntry(type, false);
         return (entry != null) ? entry.getInstance() : null;
     }
 
     public <T> List<T> getServices(Class<T> type) {
         Entry<T> entry = getEntry(type, false);
         return (entry != null) ? entry.getInstances() : null;
     }
 
     private void serviceCreationFailed(Class<?> type, Class<?> impl, Throwable exception) {
         if (errorHandler != null) {
             errorHandler.serviceCreationFailed(type, impl, exception);
         }
     }
 
     /**
      * Sets the error handler to use.
      *
      * @param errorHandler The error handler to use, may be {@code null} to ignore/swallow errors.
      */
     public void setErrorHandler(ErrorHandler errorHandler) {
         this.errorHandler = errorHandler;
     }
 
     /**
      * A hook to customize the handling of errors encountered while locating a service implementation.
      */
     public abstract static class ErrorHandler {
 
         /**
          * Handles errors during creation of a service. The default implemention does nothing.
          *
          * @param type The interface describing the service, must not be {@code null}.
          * @param impl The implementation class of the service, must not be {@code null}.
          * @param exception The error that occurred while trying to instantiate the implementation class, must not be
          *            {@code null}.
          */
         public void serviceCreationFailed(Class<?> type, Class<?> impl, Throwable exception) {}
     }
 }