/*
    * 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.apache.maven.artifact.repository.metadata;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.Reader;
  import java.io.Writer;
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.artifact.metadata.ArtifactMetadata;
  import org.apache.maven.artifact.repository.ArtifactRepository;
  import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
  import org.apache.maven.artifact.repository.metadata.io.xpp3.MetadataXpp3Reader;
  import org.apache.maven.artifact.repository.metadata.io.xpp3.MetadataXpp3Writer;
  import org.codehaus.plexus.util.ReaderFactory;
  import org.codehaus.plexus.util.WriterFactory;
  import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
  
  /**
   * Shared methods of the repository metadata handling.
   *
   * @author <a href="mailto:brett@apache.org">Brett Porter</a>
   */
  public abstract class AbstractRepositoryMetadata implements RepositoryMetadata {
      private static final String LS = System.lineSeparator();
  
      private Metadata metadata;
  
      protected AbstractRepositoryMetadata(Metadata metadata) {
          this.metadata = metadata;
      }
  
      public String getRemoteFilename() {
          return "maven-metadata.xml";
      }
  
      public String getLocalFilename(ArtifactRepository repository) {
          return "maven-metadata-" + repository.getKey() + ".xml";
      }
  
      public void storeInLocalRepository(ArtifactRepository localRepository, ArtifactRepository remoteRepository)
              throws RepositoryMetadataStoreException {
          try {
              updateRepositoryMetadata(localRepository, remoteRepository);
          } catch (IOException | XmlPullParserException e) {
              throw new RepositoryMetadataStoreException("Error updating group repository metadata", e);
          }
      }
  
      protected void updateRepositoryMetadata(ArtifactRepository localRepository, ArtifactRepository remoteRepository)
              throws IOException, XmlPullParserException {
          MetadataXpp3Reader mappingReader = new MetadataXpp3Reader();
  
          Metadata metadata = null;
  
          File metadataFile = new File(
                  localRepository.getBasedir(), localRepository.pathOfLocalRepositoryMetadata(this, remoteRepository));
  
          if (metadataFile.length() == 0) {
              if (!metadataFile.delete()) {
                  // sleep for 10ms just in case this is windows holding a file lock
                  try {
                      Thread.sleep(10);
                  } catch (InterruptedException e) {
                      // ignore
                  }
                  metadataFile.delete(); // if this fails, forget about it, we'll try to overwrite it anyway so no need
                  // to delete on exit
              }
          } else if (metadataFile.exists()) {
              try (Reader reader = ReaderFactory.newXmlReader(metadataFile)) {
                  metadata = mappingReader.read(reader, false);
              }
          }
  
          boolean changed;
  
          // If file could not be found or was not valid, start from scratch
          if (metadata == null) {
              metadata = this.metadata;
  
              changed = true;
          } else {
             changed = metadata.merge(this.metadata);
         }
 
         // beware meta-versions!
         String version = metadata.getVersion();
         if (Artifact.LATEST_VERSION.equals(version) || Artifact.RELEASE_VERSION.equals(version)) {
             // meta-versions are not valid <version/> values...don't write them.
             metadata.setVersion(null);
         }
 
         if (changed || !metadataFile.exists()) {
             metadataFile.getParentFile().mkdirs();
             try (Writer writer = WriterFactory.newXmlWriter(metadataFile)) {
                 MetadataXpp3Writer mappingWriter = new MetadataXpp3Writer();
 
                 mappingWriter.write(writer, metadata);
             }
         } else {
             metadataFile.setLastModified(System.currentTimeMillis());
         }
     }
 
     public String toString() {
         return "repository metadata for: '" + getKey() + "'";
     }
 
     protected static Metadata createMetadata(Artifact artifact, Versioning versioning) {
         Metadata metadata = new Metadata();
         metadata.setGroupId(artifact.getGroupId());
         metadata.setArtifactId(artifact.getArtifactId());
         metadata.setVersion(artifact.getVersion());
         metadata.setVersioning(versioning);
         return metadata;
     }
 
     protected static Versioning createVersioning(Snapshot snapshot) {
         Versioning versioning = new Versioning();
         versioning.setSnapshot(snapshot);
         return versioning;
     }
 
     public void setMetadata(Metadata metadata) {
         this.metadata = metadata;
     }
 
     public Metadata getMetadata() {
         return metadata;
     }
 
     public void merge(org.apache.maven.repository.legacy.metadata.ArtifactMetadata metadata) {
         // TODO not sure that it should assume this, maybe the calls to addMetadata should pre-merge, then artifact
         // replaces?
         AbstractRepositoryMetadata repoMetadata = (AbstractRepositoryMetadata) metadata;
         this.metadata.merge(repoMetadata.getMetadata());
     }
 
     public void merge(ArtifactMetadata metadata) {
         // TODO not sure that it should assume this, maybe the calls to addMetadata should pre-merge, then artifact
         // replaces?
         AbstractRepositoryMetadata repoMetadata = (AbstractRepositoryMetadata) metadata;
         this.metadata.merge(repoMetadata.getMetadata());
     }
 
     public String extendedToString() {
         StringBuilder buffer = new StringBuilder(256);
 
         buffer.append(LS).append("Repository Metadata").append(LS).append("--------------------------");
         buffer.append(LS).append("GroupId: ").append(getGroupId());
         buffer.append(LS).append("ArtifactId: ").append(getArtifactId());
         buffer.append(LS).append("Metadata Type: ").append(getClass().getName());
 
         return buffer.toString();
     }
 
     public int getNature() {
         return RELEASE;
     }
 
     public ArtifactRepositoryPolicy getPolicy(ArtifactRepository repository) {
         int nature = getNature();
         if ((nature & RepositoryMetadata.RELEASE_OR_SNAPSHOT) == RepositoryMetadata.RELEASE_OR_SNAPSHOT) {
             ArtifactRepositoryPolicy policy = new ArtifactRepositoryPolicy(repository.getReleases());
             policy.merge(repository.getSnapshots());
             return policy;
         } else if ((nature & RepositoryMetadata.SNAPSHOT) != 0) {
             return repository.getSnapshots();
         } else {
             return repository.getReleases();
         }
     }
 }