/*
    * 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.collection;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import org.eclipse.aether.RepositorySystem;
  import org.eclipse.aether.RequestTrace;
  import org.eclipse.aether.artifact.Artifact;
  import org.eclipse.aether.graph.Dependency;
  import org.eclipse.aether.repository.RemoteRepository;
  
  /**
   * A request to collect the transitive dependencies and to build a dependency graph from them. There are three ways to
   * create a dependency graph. First, only the root dependency can be given. Second, a root dependency and direct
   * dependencies can be specified in which case the specified direct dependencies are merged with the direct dependencies
   * retrieved from the artifact descriptor of the root dependency. And last, only direct dependencies can be specified in
   * which case the root node of the resulting graph has no associated dependency.
   *
   * @see RepositorySystem#collectDependencies(org.eclipse.aether.RepositorySystemSession, CollectRequest)
   */
  public final class CollectRequest {
  
      private Artifact rootArtifact;
  
      private Dependency root;
  
      private List<Dependency> dependencies = Collections.emptyList();
  
      private List<Dependency> managedDependencies = Collections.emptyList();
  
      private List<RemoteRepository> repositories = Collections.emptyList();
  
      private String context = "";
  
      private RequestTrace trace;
  
      /**
       * Creates an uninitialized request.
       */
      public CollectRequest() {
          // enables default constructor
      }
  
      /**
       * Creates a request with the specified properties.
       *
       * @param root The root dependency whose transitive dependencies should be collected, may be {@code null}.
       * @param repositories The repositories to use for the collection, may be {@code null}.
       */
      public CollectRequest(Dependency root, List<RemoteRepository> repositories) {
          setRoot(root);
          setRepositories(repositories);
      }
  
      /**
       * Creates a new request with the specified properties.
       *
       * @param root The root dependency whose transitive dependencies should be collected, may be {@code null}.
       * @param dependencies The direct dependencies to merge with the direct dependencies from the root dependency's
       *            artifact descriptor.
       * @param repositories The repositories to use for the collection, may be {@code null}.
       */
      public CollectRequest(Dependency root, List<Dependency> dependencies, List<RemoteRepository> repositories) {
          setRoot(root);
          setDependencies(dependencies);
          setRepositories(repositories);
      }
  
      /**
       * Creates a new request with the specified properties.
       *
       * @param dependencies The direct dependencies of some imaginary root, may be {@code null}.
       * @param managedDependencies The dependency management information to apply to the transitive dependencies, may be
       *            {@code null}.
       * @param repositories The repositories to use for the collection, may be {@code null}.
       */
      public CollectRequest(
              List<Dependency> dependencies, List<Dependency> managedDependencies, List<RemoteRepository> repositories) {
          setDependencies(dependencies);
          setManagedDependencies(managedDependencies);
         setRepositories(repositories);
     }
 
     /**
      * Gets the root artifact for the dependency graph.
      *
      * @return The root artifact for the dependency graph or {@code null} if none.
      */
     public Artifact getRootArtifact() {
         return rootArtifact;
     }
 
     /**
      * Sets the root artifact for the dependency graph. This must not be confused with {@link #setRoot(Dependency)}: The
      * root <em>dependency</em>, like any other specified dependency, will be subject to dependency
      * collection/resolution, i.e. should have an artifact descriptor and a corresponding artifact file. The root
      * <em>artifact</em> on the other hand is only used as a label for the root node of the graph in case no root
      * dependency was specified. As such, the configured root artifact is ignored if {@link #getRoot()} does not return
      * {@code null}.
      *
      * @param rootArtifact The root artifact for the dependency graph, may be {@code null}.
      * @return This request for chaining, never {@code null}.
      */
     public CollectRequest setRootArtifact(Artifact rootArtifact) {
         this.rootArtifact = rootArtifact;
         return this;
     }
 
     /**
      * Gets the root dependency of the graph.
      *
      * @return The root dependency of the graph or {@code null} if none.
      */
     public Dependency getRoot() {
         return root;
     }
 
     /**
      * Sets the root dependency of the graph.
      *
      * @param root The root dependency of the graph, may be {@code null}.
      * @return This request for chaining, never {@code null}.
      */
     public CollectRequest setRoot(Dependency root) {
         this.root = root;
         return this;
     }
 
     /**
      * Gets the direct dependencies.
      *
      * @return The direct dependencies, never {@code null}.
      */
     public List<Dependency> getDependencies() {
         return dependencies;
     }
 
     /**
      * Sets the direct dependencies. If both a root dependency and direct dependencies are given in the request, the
      * direct dependencies from the request will be merged with the direct dependencies from the root dependency's
      * artifact descriptor, giving higher priority to the dependencies from the request.
      *
      * @param dependencies The direct dependencies, may be {@code null}.
      * @return This request for chaining, never {@code null}.
      */
     public CollectRequest setDependencies(List<Dependency> dependencies) {
         if (dependencies == null) {
             this.dependencies = Collections.emptyList();
         } else {
             this.dependencies = dependencies;
         }
         return this;
     }
 
     /**
      * Adds the specified direct dependency.
      *
      * @param dependency The dependency to add, may be {@code null}.
      * @return This request for chaining, never {@code null}.
      */
     public CollectRequest addDependency(Dependency dependency) {
         if (dependency != null) {
             if (this.dependencies.isEmpty()) {
                 this.dependencies = new ArrayList<>();
             }
             this.dependencies.add(dependency);
         }
         return this;
     }
 
     /**
      * Gets the dependency management to apply to transitive dependencies.
      *
      * @return The dependency management to apply to transitive dependencies, never {@code null}.
      */
     public List<Dependency> getManagedDependencies() {
         return managedDependencies;
     }
 
     /**
      * Sets the dependency management to apply to transitive dependencies. To clarify, this management does not apply to
      * the direct dependencies of the root node.
      *
      * @param managedDependencies The dependency management, may be {@code null}.
      * @return This request for chaining, never {@code null}.
      */
     public CollectRequest setManagedDependencies(List<Dependency> managedDependencies) {
         if (managedDependencies == null) {
             this.managedDependencies = Collections.emptyList();
         } else {
             this.managedDependencies = managedDependencies;
         }
         return this;
     }
 
     /**
      * Adds the specified managed dependency.
      *
      * @param managedDependency The managed dependency to add, may be {@code null}.
      * @return This request for chaining, never {@code null}.
      */
     public CollectRequest addManagedDependency(Dependency managedDependency) {
         if (managedDependency != null) {
             if (this.managedDependencies.isEmpty()) {
                 this.managedDependencies = new ArrayList<>();
             }
             this.managedDependencies.add(managedDependency);
         }
         return this;
     }
 
     /**
      * Gets the repositories to use for the collection.
      *
      * @return The repositories to use for the collection, never {@code null}.
      */
     public List<RemoteRepository> getRepositories() {
         return repositories;
     }
 
     /**
      * Sets the repositories to use for the collection.
      *
      * @param repositories The repositories to use for the collection, may be {@code null}.
      * @return This request for chaining, never {@code null}.
      */
     public CollectRequest setRepositories(List<RemoteRepository> repositories) {
         if (repositories == null) {
             this.repositories = Collections.emptyList();
         } else {
             this.repositories = repositories;
         }
         return this;
     }
 
     /**
      * Adds the specified repository for collection.
      *
      * @param repository The repository to collect dependency information from, may be {@code null}.
      * @return This request for chaining, never {@code null}.
      */
     public CollectRequest addRepository(RemoteRepository repository) {
         if (repository != null) {
             if (this.repositories.isEmpty()) {
                 this.repositories = new ArrayList<>();
             }
             this.repositories.add(repository);
         }
         return this;
     }
 
     /**
      * Gets the context in which this request is made.
      *
      * @return The context, never {@code null}.
      */
     public String getRequestContext() {
         return context;
     }
 
     /**
      * Sets the context in which this request is made.
      *
      * @param context The context, may be {@code null}.
      * @return This request for chaining, never {@code null}.
      */
     public CollectRequest setRequestContext(String context) {
         this.context = (context != null) ? context.intern() : "";
         return this;
     }
 
     /**
      * Gets the trace information that describes the higher level request/operation in which this request is issued.
      *
      * @return The trace information about the higher level operation or {@code null} if none.
      */
     public RequestTrace getTrace() {
         return trace;
     }
 
     /**
      * Sets the trace information that describes the higher level request/operation in which this request is issued.
      *
      * @param trace The trace information about the higher level operation, may be {@code null}.
      * @return This request for chaining, never {@code null}.
      */
     public CollectRequest setTrace(RequestTrace trace) {
         this.trace = trace;
         return this;
     }
 
     @Override
     public String toString() {
         return getRoot() + " -> " + getDependencies() + " < " + getRepositories();
     }
 }