/*
    * 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.impl.resolver;
  
  import javax.xml.stream.XMLStreamException;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.time.Instant;
  import java.time.ZoneOffset;
  import java.time.format.DateTimeFormatter;
  import java.util.Collections;
  import java.util.Map;
  
  import org.apache.maven.api.metadata.Metadata;
  import org.apache.maven.metadata.v4.MetadataStaxReader;
  import org.apache.maven.metadata.v4.MetadataStaxWriter;
  import org.eclipse.aether.RepositoryException;
  import org.eclipse.aether.metadata.AbstractMetadata;
  import org.eclipse.aether.metadata.MergeableMetadata;
  
  /**
   */
  abstract class MavenMetadata extends AbstractMetadata implements MergeableMetadata {
  
      static final String MAVEN_METADATA_XML = "maven-metadata.xml";
  
      static DateTimeFormatter fmt;
  
      static {
          fmt = DateTimeFormatter.ofPattern("yyyyMMddHHmmss").withZone(ZoneOffset.UTC);
      }
  
      protected Metadata metadata;
  
      private final Path path;
  
      protected final Instant timestamp;
  
      private boolean merged;
  
      @Deprecated
      protected MavenMetadata(Metadata metadata, File file, Instant timestamp) {
          this(metadata, file != null ? file.toPath() : null, timestamp);
      }
  
      protected MavenMetadata(Metadata metadata, Path path, Instant timestamp) {
          this.metadata = metadata;
          this.path = path;
          this.timestamp = timestamp;
      }
  
      @Override
      public String getType() {
          return MAVEN_METADATA_XML;
      }
  
      @Deprecated
      @Override
      public File getFile() {
          return path != null ? path.toFile() : null;
      }
  
      @Override
      public Path getPath() {
          return path;
      }
  
      @Deprecated
      @Override
      public void merge(File existing, File result) throws RepositoryException {
          merge(existing != null ? existing.toPath() : null, result != null ? result.toPath() : null);
      }
  
      @Override
      public void merge(Path existing, Path result) throws RepositoryException {
          Metadata recessive = read(existing);
  
          merge(recessive);
 
         write(result, metadata);
 
         merged = true;
     }
 
     @Override
     public boolean isMerged() {
         return merged;
     }
 
     protected abstract void merge(Metadata recessive);
 
     static Metadata read(Path metadataPath) throws RepositoryException {
         if (!Files.exists(metadataPath)) {
             return Metadata.newInstance();
         }
 
         try (InputStream input = Files.newInputStream(metadataPath)) {
             return new MetadataStaxReader().read(input, false);
         } catch (IOException | XMLStreamException e) {
             throw new RepositoryException("Could not parse metadata " + metadataPath + ": " + e.getMessage(), e);
         }
     }
 
     private void write(Path metadataPath, Metadata metadata) throws RepositoryException {
         try {
             Files.createDirectories(metadataPath.getParent());
             try (OutputStream output = Files.newOutputStream(metadataPath)) {
                 new MetadataStaxWriter().write(output, metadata);
             }
         } catch (IOException | XMLStreamException e) {
             throw new RepositoryException("Could not write metadata " + metadataPath + ": " + e.getMessage(), e);
         }
     }
 
     @Override
     public Map<String, String> getProperties() {
         return Collections.emptyMap();
     }
 
     @Override
     public org.eclipse.aether.metadata.Metadata setProperties(Map<String, String> properties) {
         return this;
     }
 }