package org.apache.archiva.metadata.repository;
   
   /*
    * 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.
   */
  
  import org.apache.archiva.metadata.model.ArtifactMetadata;
  import org.apache.archiva.metadata.model.ProjectMetadata;
  import org.apache.archiva.metadata.model.ProjectVersionMetadata;
  import org.apache.archiva.metadata.model.ProjectVersionReference;
  import org.apache.archiva.filter.ExcludesFilter;
  import org.apache.archiva.metadata.repository.storage.ReadMetadataRequest;
  import org.apache.archiva.metadata.repository.storage.RepositoryStorage;
  import org.apache.archiva.metadata.repository.storage.RepositoryStorageMetadataInvalidException;
  import org.apache.archiva.metadata.repository.storage.RepositoryStorageMetadataNotFoundException;
  import org.apache.archiva.metadata.repository.storage.RepositoryStorageRuntimeException;
  import org.apache.archiva.components.cache.Cache;
  import org.apache.archiva.metadata.audit.RepositoryListener;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.stereotype.Service;
  
  import javax.inject.Inject;
  import javax.inject.Named;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  /**
   * <p>
   * Default implementation of the metadata resolver API. At present it will handle updating the content repository
   * from new or changed information in the model and artifacts from the repository storage.
   * </p>
   * <p>
   * This is a singleton component to allow an alternate implementation to be provided. It is intended to be the same
   * system-wide for the whole content repository instead of on a per-managed-repository basis. Therefore, the session is
   * passed in as an argument to obtain any necessary resources, rather than the class being instantiated within the
   * session in the context of a single managed repository's resolution needs.
   * </p>
   * <p>
   * Note that the caller is responsible for the session, such as closing and saving (which is implied by the resolver
   * being obtained from within the session). The {@link RepositorySession#markDirty()} method is used as a hint to ensure
   * that the session knows we've made changes at close. We cannot ensure the changes will be persisted if the caller
   * chooses to revert first. This is preferable to storing the metadata immediately - a separate session would require
   * having a bi-directional link with the session factory, and saving the existing session might save other changes
   * unknowingly by the caller.
   * </p>
   */
  @Service("metadataResolver#default")
  public class DefaultMetadataResolver
      implements MetadataResolver
  {
  
      private Logger log = LoggerFactory.getLogger( DefaultMetadataResolver.class );
  
      /**
       * <p>
       * FIXME: this needs to be configurable based on storage type - and could also be instantiated per repo. Change to a
       * factory, and perhaps retrieve from the session. We should avoid creating one per request, however.
       * </p>
       * <p>
       * TODO: Also need to accommodate availability of proxy module
       * ... could be a different type since we need methods to modify the storage metadata, which would also allow more
       * appropriate methods to pass in the already determined repository configuration, for example, instead of the ID
       * </p>
       */
      @Inject
      @Named(value = "repositoryStorage#maven2")
      private RepositoryStorage repositoryStorage;
  
      @Inject
      @Autowired(required = false)
      private List<RepositoryListener> listeners = new ArrayList<>();
  
      /**
       * Cache used for namespaces
       */
      @Inject
      @Named( value = "cache#namespaces" )
      private Cache<String, Collection<String>> namespacesCache;
  
      @Override
      public ProjectVersionMetadata resolveProjectVersion( RepositorySession session, String repoId, String namespace,
                                                          String projectId, String projectVersion )
         throws MetadataResolutionException
     {
         MetadataRepository metadataRepository = session.getRepository();
 
         ProjectVersionMetadata metadata =
             metadataRepository.getProjectVersion( session, repoId, namespace, projectId, projectVersion );
         // TODO: do we want to detect changes as well by comparing timestamps? isProjectVersionNewerThan(updated)
         //       in such cases we might also remove/update stale metadata, including adjusting plugin-based facets
         //       This would also be better than checking for completeness - we can then refresh only when fixed (though
         //       sometimes this has an additional dependency - such as a parent - requesting the user to force an update
         //       may then work here and be more efficient than always trying again)
         if ( metadata == null || metadata.isIncomplete() )
         {
             try
             {
                 ReadMetadataRequest readMetadataRequest =
                     new ReadMetadataRequest().repositoryId( repoId ).namespace( namespace ).projectId(
                         projectId ).projectVersion( projectVersion ).browsingRequest( true );
                 metadata = repositoryStorage.readProjectVersionMetadata( readMetadataRequest );
 
                 log.debug( "Resolved project version metadata from storage: {}", metadata );
 
                 // FIXME: make this a more generic post-processing that plugins can take advantage of
                 //       eg. maven projects should be able to process parent here
                 if ( !metadata.getDependencies().isEmpty() )
                 {
                     ProjectVersionReferencectVersionReference.html#ProjectVersionReference">ProjectVersionReference ref = new ProjectVersionReference();
                     ref.setNamespace( namespace );
                     ref.setProjectId( projectId );
                     ref.setProjectVersion( projectVersion );
                     ref.setReferenceType( ProjectVersionReference.ReferenceType.DEPENDENCY );
                 }
                 try
                 {
                     for ( RepositoryListener listener : listeners )
                     {
                         listener.addArtifact( session, repoId, namespace, projectId, metadata );
                     }
                     metadataRepository.updateProjectVersion( session, repoId, namespace, projectId, metadata );
                 }
                 catch ( MetadataRepositoryException e )
                 {
                     log.warn( "Unable to persist resolved information: {}", e.getMessage(), e );
                 }
 
                 session.markDirty();
             }
             catch ( RepositoryStorageMetadataInvalidException e )
             {
                 for ( RepositoryListener listener : listeners )
                 {
                     listener.addArtifactProblem( session, repoId, namespace, projectId, projectVersion, e );
                 }
                 throw new MetadataResolutionException( e.getMessage(), e );
             }
             catch ( RepositoryStorageMetadataNotFoundException e )
             {
                 for ( RepositoryListener listener : listeners )
                 {
                     listener.addArtifactProblem( session, repoId, namespace, projectId, projectVersion, e );
                 }
                 // no need to rethrow - return null
             }
             catch ( RepositoryStorageRuntimeException e )
             {
                 for ( RepositoryListener listener : listeners )
                 {
                     listener.addArtifactProblem( session, repoId, namespace, projectId, projectVersion, e );
                 }
                 throw new MetadataResolutionException( e.getMessage(), e );
             }
 
         }
         return metadata;
     }
 
     @Override
     public Collection<ProjectVersionReference> resolveProjectReferences( RepositorySession session, String repoId,
                                                                          String namespace, String projectId,
                                                                          String projectVersion )
         throws MetadataResolutionException
     {
         // TODO: is this assumption correct? could a storage mech. actually know all references in a non-Maven scenario?
         // not passed to the storage mechanism as resolving references would require iterating all artifacts
         MetadataRepository metadataRepository = session.getRepository();
         return metadataRepository.getProjectReferences( session, repoId, namespace, projectId, projectVersion );
     }
 
     @Override
     public Collection<String> resolveRootNamespaces( RepositorySession session, String repoId )
         throws MetadataResolutionException
     {
         try
         {
 
             Collection<String> namespaces = namespacesCache.get( repoId );
             if ( namespaces != null )
             {
                 return namespaces;
             }
 
             MetadataRepository metadataRepository = session.getRepository();
             namespaces = metadataRepository.getRootNamespaces( session, repoId );
             Collection<String> storageNamespaces =
                 repositoryStorage.listRootNamespaces( repoId, new ExcludesFilter<String>( namespaces ) );
             if ( storageNamespaces != null && !storageNamespaces.isEmpty() )
             {
 
                 log.debug( "Resolved root namespaces from storage: {}", storageNamespaces );
 
                 for ( String n : storageNamespaces )
                 {
                     try
                     {
                         metadataRepository.updateNamespace( session, repoId, n );
                         // just invalidate cache entry
                         String cacheKey = repoId + "-" + n;
                         namespacesCache.remove( cacheKey );
                     }
                     catch ( MetadataRepositoryException e )
                     {
                         log.warn( "Unable to persist resolved information: {}", e.getMessage(), e );
                     }
                 }
                 session.markDirty();
 
                 namespaces = new ArrayList<>( namespaces );
                 namespaces.addAll( storageNamespaces );
             }
 
             namespacesCache.put( repoId, namespaces );
 
             return namespaces;
         }
         catch ( RepositoryStorageRuntimeException e )
         {
             throw new MetadataResolutionException( e.getMessage(), e );
         }
     }
 
     @Override
     public Collection<String> resolveNamespaces( RepositorySession session, String repoId, String namespace )
         throws MetadataResolutionException
     {
         try
         {
             MetadataRepository metadataRepository = session.getRepository();
             String cacheKey = repoId + "-" + namespace;
             Collection<String> namespaces = namespacesCache.get( cacheKey );
             if ( namespaces == null )
             {
                 namespaces = metadataRepository.getChildNamespaces( session, repoId, namespace );
                 namespacesCache.put( cacheKey, namespaces );
             }
             Collection<String> exclusions = new ArrayList<>( namespaces );
             exclusions.addAll( metadataRepository.getProjects( session, repoId, namespace ) );
             Collection<String> storageNamespaces =
                 repositoryStorage.listNamespaces( repoId, namespace, new ExcludesFilter<String>( exclusions ) );
             if ( storageNamespaces != null && !storageNamespaces.isEmpty() )
             {
 
                 log.debug( "Resolved namespaces from storage: {}", storageNamespaces );
 
                 for ( String n : storageNamespaces )
                 {
                     try
                     {
                         metadataRepository.updateNamespace( session, repoId, namespace + "." + n );
                         // just invalidate cache entry
                         cacheKey = repoId + "-" + namespace + "." + n;
                         namespacesCache.remove( cacheKey );
                     }
                     catch ( MetadataRepositoryException e )
                     {
                         log.warn( "Unable to persist resolved information: {}", e.getMessage(), e );
                     }
                 }
                 session.markDirty();
 
                 namespaces = new ArrayList<>( namespaces );
                 namespaces.addAll( storageNamespaces );
             }
             return namespaces;
         }
         catch ( RepositoryStorageRuntimeException e )
         {
             throw new MetadataResolutionException( e.getMessage(), e );
         }
     }
 
     @Override
     public Collection<String> resolveProjects( RepositorySession session, String repoId, String namespace )
         throws MetadataResolutionException
     {
         try
         {
             MetadataRepository metadataRepository = session.getRepository();
             Collection<String> projects = metadataRepository.getProjects( session, repoId, namespace );
             Collection<String> exclusions = new ArrayList<>( projects );
 
             String cacheKey = repoId + "-" + namespace;
             Collection<String> namespaces = namespacesCache.get( cacheKey );
             if ( namespaces == null )
             {
                 namespaces = metadataRepository.getChildNamespaces( session, repoId, namespace );
                 namespacesCache.put( cacheKey, namespaces );
             }
 
             exclusions.addAll( namespaces );
 
             Collection<String> storageProjects =
                 repositoryStorage.listProjects( repoId, namespace, new ExcludesFilter<>( exclusions ) );
             if ( storageProjects != null && !storageProjects.isEmpty() )
             {
 
                 log.debug( "Resolved projects from storage: {}", storageProjects );
                 for ( String projectId : storageProjects )
                 {
                     ProjectMetadata projectMetadata =
                         repositoryStorage.readProjectMetadata( repoId, namespace, projectId );
                     if ( projectMetadata != null )
                     {
                         try
                         {
                             metadataRepository.updateProject( session, repoId, projectMetadata );
                         }
                         catch ( MetadataRepositoryException e )
                         {
                             log.warn( "Unable to persist resolved information: {}", e.getMessage(), e );
                         }
                     }
                 }
                 session.markDirty();
 
                 projects = new ArrayList<>( projects );
                 projects.addAll( storageProjects );
             }
             return projects;
         }
         catch ( RepositoryStorageRuntimeException e )
         {
             throw new MetadataResolutionException( e.getMessage(), e );
         }
     }
 
     @Override
     public Collection<String> resolveProjectVersions( RepositorySession session, String repoId, String namespace,
                                                       String projectId )
         throws MetadataResolutionException
     {
         try
         {
             MetadataRepository metadataRepository = session.getRepository();
 
             Collection<String> projectVersions = metadataRepository.getProjectVersions( session, repoId, namespace, projectId );
             Collection<String> storageProjectVersions =
                 repositoryStorage.listProjectVersions( repoId, namespace, projectId,
                                                        new ExcludesFilter<String>( projectVersions ) );
             if ( storageProjectVersions != null && !storageProjectVersions.isEmpty() )
             {
                 log.debug( "Resolved project versions from storage: {}", storageProjectVersions );
 
                 for ( String projectVersion : storageProjectVersions )
                 {
                     try
                     {
                         ReadMetadataRequest readMetadataRequest =
                             new ReadMetadataRequest().repositoryId( repoId ).namespace( namespace ).projectId(
                                 projectId ).projectVersion( projectVersion );
                         ProjectVersionMetadata versionMetadata =
                             repositoryStorage.readProjectVersionMetadata( readMetadataRequest );
                         for ( RepositoryListener listener : listeners )
                         {
                             listener.addArtifact( session, repoId, namespace, projectId, versionMetadata );
                         }
 
                         metadataRepository.updateProjectVersion( session, repoId, namespace, projectId, versionMetadata );
                     }
                     catch ( MetadataRepositoryException e )
                     {
                         log.warn( "Unable to persist resolved information: {}", e.getMessage(), e );
                     }
                     catch ( RepositoryStorageMetadataInvalidException e )
                     {
                         log.warn(
                             "Not update project in metadata repository due to an error resolving it from storage: {}",
                             e.getMessage() );
 
                         for ( RepositoryListener listener : listeners )
                         {
                             listener.addArtifactProblem( session, repoId, namespace, projectId, projectVersion, e );
                         }
                     }
                     catch ( RepositoryStorageMetadataNotFoundException e )
                     {
                         for ( RepositoryListener listener : listeners )
                         {
                             listener.addArtifactProblem( session, repoId, namespace, projectId, projectVersion, e );
                         }
                     }
                 }
                 session.markDirty();
 
                 projectVersions = new ArrayList<>( projectVersions );
                 projectVersions.addAll( storageProjectVersions );
             }
             return projectVersions;
         }
         catch ( RepositoryStorageRuntimeException e )
         {
             throw new MetadataResolutionException( e.getMessage(), e );
         }
     }
 
     @Override
     public Collection<ArtifactMetadata> resolveArtifacts( RepositorySession session, String repoId, String namespace,
                                                           String projectId, String projectVersion )
         throws MetadataResolutionException
     {
         try
         {
             MetadataRepository metadataRepository = session.getRepository();
             Collection<ArtifactMetadata> artifacts =
                 metadataRepository.getArtifacts( session, repoId, namespace, projectId, projectVersion );
             ExcludesFilter<String> filter = new ExcludesFilter<String>( createArtifactIdList( artifacts ) );
 
             ReadMetadataRequest readMetadataRequest =
                 new ReadMetadataRequest().repositoryId( repoId ).namespace( namespace ).projectId(
                     projectId ).projectVersion( projectVersion ).filter( filter );
 
             Collection<ArtifactMetadata> storageArtifacts =
                 repositoryStorage.readArtifactsMetadata( readMetadataRequest );
             if ( storageArtifacts != null && !storageArtifacts.isEmpty() )
             {
 
                 log.debug( "Resolved artifacts from storage: {}", storageArtifacts );
 
                 for ( ArtifactMetadata artifact : storageArtifacts )
                 {
                     try
                     {
                         metadataRepository.updateArtifact( session, repoId, namespace, projectId, projectVersion, artifact );
                     }
                     catch ( MetadataRepositoryException e )
                     {
                         log.warn( "Unable to persist resolved information: {}", e.getMessage(), e );
                     }
                 }
                 session.markDirty();
 
                 artifacts = new ArrayList<>( artifacts );
                 artifacts.addAll( storageArtifacts );
             }
             return artifacts;
         }
         catch ( RepositoryStorageRuntimeException e )
         {
             for ( RepositoryListener listener : listeners )
             {
                 listener.addArtifactProblem( session, repoId, namespace, projectId, projectVersion, e );
             }
             throw new MetadataResolutionException( e.getMessage(), e );
         }
     }
 
     private Collection<String> createArtifactIdList( Collection<ArtifactMetadata> artifacts )
     {
         Collection<String> artifactIds = new ArrayList<>();
         for ( ArtifactMetadata artifact : artifacts )
         {
             artifactIds.add( artifact.getId() );
         }
         return artifactIds;
     }
 }