/*
    * 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.api.model;
  
  import java.io.Serializable;
  import java.util.Collection;
  import java.util.List;
  import java.util.Objects;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  /**
   * Represents the source of a model input, such as a POM file.
   * <p>
   * This class tracks the origin of model elements, including their location in source files
   * and relationships between imported models. It's used for error reporting and debugging
   * to help identify where specific model elements came from.
   *
   * @since 4.0.0
   */
  public class InputSource implements Serializable {
  
      private final String modelId;
      private final String location;
      private final List<InputSource> inputs;
      private final InputLocation importedFrom;
  
      public InputSource(String modelId, String location) {
          this(modelId, location, null);
      }
  
      public InputSource(String modelId, String location, InputLocation importedFrom) {
          this.modelId = modelId;
          this.location = location;
          this.inputs = null;
          this.importedFrom = importedFrom;
      }
  
      public InputSource(Collection<InputSource> inputs) {
          this.modelId = null;
          this.location = null;
          this.inputs = ImmutableCollections.copy(inputs);
          this.importedFrom = null;
      }
  
      /**
       * Get the path/URL of the POM or {@code null} if unknown.
       *
       * @return the location
       */
      public String getLocation() {
          return this.location;
      }
  
      /**
       * Get the identifier of the POM in the format {@code <groupId>:<artifactId>:<version>}.
       *
       * @return the model id
       */
      public String getModelId() {
          return this.modelId;
      }
  
      /**
       * Gets the parent InputLocation where this InputLocation may have been imported from.
       * Can return {@code null}.
       *
       * @return InputLocation
       * @since 4.0.0
       */
      public InputLocation getImportedFrom() {
          return importedFrom;
      }
  
      @Override
      public boolean equals(Object o) {
          if (this == o) {
              return true;
          }
          if (o == null || getClass() != o.getClass()) {
              return false;
          }
          InputSource that = (InputSource) o;
         return Objects.equals(modelId, that.modelId)
                 && Objects.equals(location, that.location)
                 && Objects.equals(inputs, that.inputs);
     }
 
     @Override
     public int hashCode() {
         return Objects.hash(modelId, location, inputs);
     }
 
     Stream<InputSource> sources() {
         return inputs != null ? inputs.stream() : Stream.of(this);
     }
 
     @Override
     public String toString() {
         if (inputs != null) {
             return inputs.stream().map(InputSource::toString).collect(Collectors.joining(", ", "merged[", "]"));
         }
         return getModelId() + " " + getLocation();
     }
 
     public static InputSource merge(InputSource src1, InputSource src2) {
         return new InputSource(Stream.concat(src1.sources(), src2.sources()).collect(Collectors.toSet()));
     }
 }