/*
    * 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.metadata;
  
  import java.io.File;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  
  /**
   * A skeleton class for metadata.
   */
  public abstract class AbstractMetadata implements Metadata {
  
      private Metadata newInstance(Map<String, String> properties, File file) {
          return new DefaultMetadata(
                  getGroupId(), getArtifactId(), getVersion(), getType(), getNature(), file, properties);
      }
  
      public Metadata setFile(File file) {
          File current = getFile();
          if (Objects.equals(current, file)) {
              return this;
          }
          return newInstance(getProperties(), file);
      }
  
      public Metadata setProperties(Map<String, String> properties) {
          Map<String, String> current = getProperties();
          if (current.equals(properties) || (properties == null && current.isEmpty())) {
              return this;
          }
          return newInstance(copyProperties(properties), getFile());
      }
  
      public String getProperty(String key, String defaultValue) {
          String value = getProperties().get(key);
          return (value != null) ? value : defaultValue;
      }
  
      /**
       * Copies the specified metadata properties. This utility method should be used when creating new metadata instances
       * with caller-supplied properties.
       *
       * @param properties The properties to copy, may be {@code null}.
       * @return The copied and read-only properties, never {@code null}.
       */
      protected static Map<String, String> copyProperties(Map<String, String> properties) {
          if (properties != null && !properties.isEmpty()) {
              return Collections.unmodifiableMap(new HashMap<>(properties));
          } else {
              return Collections.emptyMap();
          }
      }
  
      @Override
      public String toString() {
          StringBuilder buffer = new StringBuilder(128);
          if (getGroupId().length() > 0) {
              buffer.append(getGroupId());
          }
          if (getArtifactId().length() > 0) {
              buffer.append(':').append(getArtifactId());
          }
          if (getVersion().length() > 0) {
              buffer.append(':').append(getVersion());
          }
          buffer.append('/').append(getType());
          return buffer.toString();
      }
  
      /**
       * Compares this metadata with the specified object.
       *
       * @param obj The object to compare this metadata against, may be {@code null}.
       * @return {@code true} if and only if the specified object is another {@link Metadata} with equal coordinates,
       *         type, nature, properties and file, {@code false} otherwise.
       */
      @Override
      public boolean equals(Object obj) {
          if (obj == this) {
              return true;
         } else if (!(obj instanceof Metadata)) {
             return false;
         }
 
         Metadata that = (Metadata) obj;
 
         return Objects.equals(getArtifactId(), that.getArtifactId())
                 && Objects.equals(getGroupId(), that.getGroupId())
                 && Objects.equals(getVersion(), that.getVersion())
                 && Objects.equals(getType(), that.getType())
                 && Objects.equals(getNature(), that.getNature())
                 && Objects.equals(getFile(), that.getFile())
                 && Objects.equals(getProperties(), that.getProperties());
     }
 
     /**
      * Returns a hash code for this metadata.
      *
      * @return A hash code for the metadata.
      */
     @Override
     public int hashCode() {
         int hash = 17;
         hash = hash * 31 + getGroupId().hashCode();
         hash = hash * 31 + getArtifactId().hashCode();
         hash = hash * 31 + getType().hashCode();
         hash = hash * 31 + getNature().hashCode();
         hash = hash * 31 + getVersion().hashCode();
         hash = hash * 31 + hash(getFile());
         return hash;
     }
 
     private static int hash(Object obj) {
         return (obj != null) ? obj.hashCode() : 0;
     }
 }