/*
    * 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.util.graph.manager;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.LinkedHashSet;
  import java.util.Objects;
  
  import org.eclipse.aether.artifact.Artifact;
  import org.eclipse.aether.collection.DependencyCollectionContext;
  import org.eclipse.aether.collection.DependencyManagement;
  import org.eclipse.aether.collection.DependencyManager;
  import org.eclipse.aether.graph.Dependency;
  import org.eclipse.aether.graph.Exclusion;
  import org.eclipse.aether.scope.ScopeManager;
  import org.eclipse.aether.scope.SystemDependencyScope;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A dependency manager support class.
   * <p>
   * This implementation is Maven specific, as it works hand-in-hand along with Maven ModelBuilder. While model builder
   * handles dependency management in the context of single POM (inheritance, imports, etc.), this implementation carries
   * in-lineage modifications based on previously recorded dependency management rules sourced from ascendants while
   * building the dependency graph. Root sourced management rules are special, in a way they are always applied, while
   * en-route collected ones are carefully applied to proper descendants only, to not override work done by model
   * builder already.
   * <p>
   * Details: Model builder handles version, scope from own dependency management (think "effective POM"). On the other
   * hand it does not handle optional for example. System paths are aligned across whole graph, making sure there is
   * same system path used by same dependency. Finally, exclusions (exclusions are additional information not effective
   * or applied in same POM) are always applied. This implementation makes sure, that version and scope are not applied
   * onto same node that actually provided the rules, to no override work that ModelBuilder did. It achieves this goal
   * by tracking "depth" for each collected rule and ignoring rules coming from same depth as processed dependency node is.
   * <p>
   * Note for future: the field {@code managedLocalPaths} is <em>intentionally left out of hash/equals</em>, with
   * reason explained above.
   * <p>
   * Implementation note for all managers extending this class: this class maintains "path" (list of parent managers)
   * and "depth". Depth {@code 0} is basically used as "factory" on session; is the instance created during session
   * creation and is usually empty (just parameterized). Depth 1 is the current collection "root", depth 2
   * are direct dependencies, depth 3 first level of transitive dependencies of direct dependencies and so on. Hence, on
   * depth 1 (the collection root, initialized with management possibly as well) parent will be always the empty "factory"
   * instance, and we need special handling: "apply onto itself". This does not stand on depth > 1.
   *
   * @since 2.0.0
   */
  public abstract class AbstractDependencyManager implements DependencyManager {
      protected final ArrayList<AbstractDependencyManager> path;
  
      protected final int depth;
  
      protected final int deriveUntil;
  
      protected final int applyFrom;
  
      protected final MMap<Key, String> managedVersions;
  
      protected final MMap<Key, String> managedScopes;
  
      protected final MMap<Key, Boolean> managedOptionals;
  
      protected final MMap<Key, String> managedLocalPaths;
  
      protected final MMap<Key, Holder<Collection<Exclusion>>> managedExclusions;
  
      protected final SystemDependencyScope systemDependencyScope;
  
      private final int hashCode;
  
      protected AbstractDependencyManager(int deriveUntil, int applyFrom, ScopeManager scopeManager) {
          this(
                  new ArrayList<>(),
                  0,
                  deriveUntil,
                  applyFrom,
                  null,
                  null,
                  null,
                  null,
                 null,
                 scopeManager != null
                         ? scopeManager.getSystemDependencyScope().orElse(null)
                         : SystemDependencyScope.LEGACY);
     }
 
     @SuppressWarnings("checkstyle:ParameterNumber")
     protected AbstractDependencyManager(
             ArrayList<AbstractDependencyManager> path,
             int depth,
             int deriveUntil,
             int applyFrom,
             MMap<Key, String> managedVersions,
             MMap<Key, String> managedScopes,
             MMap<Key, Boolean> managedOptionals,
             MMap<Key, String> managedLocalPaths,
             MMap<Key, Holder<Collection<Exclusion>>> managedExclusions,
             SystemDependencyScope systemDependencyScope) {
         this.path = path;
         this.depth = depth;
         this.deriveUntil = deriveUntil;
         this.applyFrom = applyFrom;
         this.managedVersions = managedVersions;
         this.managedScopes = managedScopes;
         this.managedOptionals = managedOptionals;
         this.managedLocalPaths = managedLocalPaths;
         this.managedExclusions = managedExclusions;
         // nullable: if using scope manager, but there is no system scope defined
         this.systemDependencyScope = systemDependencyScope;
 
         // exclude managedLocalPaths
         this.hashCode = Objects.hash(path, depth, managedVersions, managedScopes, managedOptionals, managedExclusions);
     }
 
     protected abstract DependencyManager newInstance(
             MMap<Key, String> managedVersions,
             MMap<Key, String> managedScopes,
             MMap<Key, Boolean> managedOptionals,
             MMap<Key, String> managedLocalPaths,
             MMap<Key, Holder<Collection<Exclusion>>> managedExclusions);
 
     private boolean containsManagedVersion(Key key) {
         for (AbstractDependencyManager ancestor : path) {
             if (ancestor.managedVersions != null && ancestor.managedVersions.containsKey(key)) {
                 return true;
             }
         }
         return managedVersions != null && managedVersions.containsKey(key);
     }
 
     private String getManagedVersion(Key key) {
         for (AbstractDependencyManager ancestor : path) {
             if (ancestor.managedVersions != null && ancestor.managedVersions.containsKey(key)) {
                 return ancestor.managedVersions.get(key);
             }
         }
         if (depth == 1 && managedVersions != null && managedVersions.containsKey(key)) {
             return managedVersions.get(key);
         }
         return null;
     }
 
     private boolean containsManagedScope(Key key) {
         for (AbstractDependencyManager ancestor : path) {
             if (ancestor.managedScopes != null && ancestor.managedScopes.containsKey(key)) {
                 return true;
             }
         }
         return managedScopes != null && managedScopes.containsKey(key);
     }
 
     private String getManagedScope(Key key) {
         for (AbstractDependencyManager ancestor : path) {
             if (ancestor.managedScopes != null && ancestor.managedScopes.containsKey(key)) {
                 return ancestor.managedScopes.get(key);
             }
         }
         if (depth == 1 && managedScopes != null && managedScopes.containsKey(key)) {
             return managedScopes.get(key);
         }
         return null;
     }
 
     private boolean containsManagedOptional(Key key) {
         for (AbstractDependencyManager ancestor : path) {
             if (ancestor.managedOptionals != null && ancestor.managedOptionals.containsKey(key)) {
                 return true;
             }
         }
         return managedOptionals != null && managedOptionals.containsKey(key);
     }
 
     private Boolean getManagedOptional(Key key) {
         for (AbstractDependencyManager ancestor : path) {
             if (ancestor.managedOptionals != null && ancestor.managedOptionals.containsKey(key)) {
                 return ancestor.managedOptionals.get(key);
             }
         }
         if (depth == 1 && managedOptionals != null && managedOptionals.containsKey(key)) {
             return managedOptionals.get(key);
         }
         return null;
     }
 
     private boolean containsManagedLocalPath(Key key) {
         for (AbstractDependencyManager ancestor : path) {
             if (ancestor.managedLocalPaths != null && ancestor.managedLocalPaths.containsKey(key)) {
                 return true;
             }
         }
         return managedLocalPaths != null && managedLocalPaths.containsKey(key);
     }
 
     private String getManagedLocalPath(Key key) {
         for (AbstractDependencyManager ancestor : path) {
             if (ancestor.managedLocalPaths != null && ancestor.managedLocalPaths.containsKey(key)) {
                 return ancestor.managedLocalPaths.get(key);
             }
         }
         if (managedLocalPaths != null && managedLocalPaths.containsKey(key)) {
             return managedLocalPaths.get(key);
         }
         return null;
     }
 
     /**
      * Merges all way down.
      */
     private Collection<Exclusion> getManagedExclusions(Key key) {
         ArrayList<Exclusion> result = new ArrayList<>();
         for (AbstractDependencyManager ancestor : path) {
             if (ancestor.managedExclusions != null && ancestor.managedExclusions.containsKey(key)) {
                 result.addAll(ancestor.managedExclusions.get(key).value);
             }
         }
         if (managedExclusions != null && managedExclusions.containsKey(key)) {
             result.addAll(managedExclusions.get(key).value);
         }
         return result.isEmpty() ? null : result;
     }
 
     @Override
     public DependencyManager deriveChildManager(DependencyCollectionContext context) {
         requireNonNull(context, "context cannot be null");
         if (!isDerived()) {
             return this;
         }
 
         MMap<Key, String> managedVersions = null;
         MMap<Key, String> managedScopes = null;
         MMap<Key, Boolean> managedOptionals = null;
         MMap<Key, String> managedLocalPaths = null;
         MMap<Key, Holder<Collection<Exclusion>>> managedExclusions = null;
 
         for (Dependency managedDependency : context.getManagedDependencies()) {
             Artifact artifact = managedDependency.getArtifact();
             Key key = new Key(artifact);
 
             String version = artifact.getVersion();
             if (!version.isEmpty() && !containsManagedVersion(key)) {
                 if (managedVersions == null) {
                     managedVersions = MMap.emptyNotDone();
                 }
                 managedVersions.put(key, version);
             }
 
             String scope = managedDependency.getScope();
             if (!scope.isEmpty() && !containsManagedScope(key)) {
                 if (managedScopes == null) {
                     managedScopes = MMap.emptyNotDone();
                 }
                 managedScopes.put(key, scope);
             }
 
             Boolean optional = managedDependency.getOptional();
             if (optional != null && !containsManagedOptional(key)) {
                 if (managedOptionals == null) {
                     managedOptionals = MMap.emptyNotDone();
                 }
                 managedOptionals.put(key, optional);
             }
 
             String localPath = systemDependencyScope == null
                     ? null
                     : systemDependencyScope.getSystemPath(managedDependency.getArtifact());
             if (localPath != null && !containsManagedLocalPath(key)) {
                 if (managedLocalPaths == null) {
                     managedLocalPaths = MMap.emptyNotDone();
                 }
                 managedLocalPaths.put(key, localPath);
             }
 
             Collection<Exclusion> exclusions = managedDependency.getExclusions();
             if (!exclusions.isEmpty()) {
                 if (managedExclusions == null) {
                     managedExclusions = MMap.emptyNotDone();
                 }
                 Holder<Collection<Exclusion>> managed = managedExclusions.get(key);
                 if (managed != null) {
                     ArrayList<Exclusion> ex = new ArrayList<>(managed.getValue());
                     ex.addAll(exclusions);
                     managed = new Holder<>(ex);
                     managedExclusions.put(key, managed);
                 } else {
                     managedExclusions.put(key, new Holder<>(exclusions));
                 }
             }
         }
 
         return newInstance(
                 managedVersions != null ? managedVersions.done() : null,
                 managedScopes != null ? managedScopes.done() : null,
                 managedOptionals != null ? managedOptionals.done() : null,
                 managedLocalPaths != null ? managedLocalPaths.done() : null,
                 managedExclusions != null ? managedExclusions.done() : null);
     }
 
     @Override
     public DependencyManagement manageDependency(Dependency dependency) {
         requireNonNull(dependency, "dependency cannot be null");
         DependencyManagement management = null;
         Key key = new Key(dependency.getArtifact());
 
         if (isApplied()) {
             String version = getManagedVersion(key);
             // is managed locally by model builder
             // apply only rules coming from "higher" levels
             if (version != null) {
                 management = new DependencyManagement();
                 management.setVersion(version);
             }
 
             String scope = getManagedScope(key);
             // is managed locally by model builder
             // apply only rules coming from "higher" levels
             if (scope != null) {
                 if (management == null) {
                     management = new DependencyManagement();
                 }
                 management.setScope(scope);
 
                 if (systemDependencyScope != null
                         && !systemDependencyScope.is(scope)
                         && systemDependencyScope.getSystemPath(dependency.getArtifact()) != null) {
                     HashMap<String, String> properties =
                             new HashMap<>(dependency.getArtifact().getProperties());
                     systemDependencyScope.setSystemPath(properties, null);
                     management.setProperties(properties);
                 }
             }
 
             // system scope paths always applied to have them aligned
             // (same artifact == same path) in whole graph
             if (systemDependencyScope != null
                     && (scope != null && systemDependencyScope.is(scope)
                             || (scope == null && systemDependencyScope.is(dependency.getScope())))) {
                 String localPath = getManagedLocalPath(key);
                 if (localPath != null) {
                     if (management == null) {
                         management = new DependencyManagement();
                     }
                     HashMap<String, String> properties =
                             new HashMap<>(dependency.getArtifact().getProperties());
                     systemDependencyScope.setSystemPath(properties, localPath);
                     management.setProperties(properties);
                 }
             }
 
             // optional is not managed by model builder
             // apply only rules coming from "higher" levels
             Boolean optional = getManagedOptional(key);
             if (optional != null) {
                 if (management == null) {
                     management = new DependencyManagement();
                 }
                 management.setOptional(optional);
             }
         }
 
         // exclusions affect only downstream
         // this will not "exclude" own dependency,
         // is just added as additional information
         // ModelBuilder does not merge exclusions (only applies if dependency does not have exclusion)
         // so we merge it here even from same level
         Collection<Exclusion> exclusions = getManagedExclusions(key);
         if (exclusions != null) {
             if (management == null) {
                 management = new DependencyManagement();
             }
             Collection<Exclusion> result = new LinkedHashSet<>(dependency.getExclusions());
             result.addAll(exclusions);
             management.setExclusions(result);
         }
 
         return management;
     }
 
     /**
      * Returns {@code true} if current context should be factored in (collected/derived).
      */
     protected boolean isDerived() {
         return depth < deriveUntil;
     }
 
     /**
      * Returns {@code true} if current dependency should be managed according to so far collected/derived rules.
      */
     protected boolean isApplied() {
         return depth >= applyFrom;
     }
 
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
             return true;
         } else if (null == obj || !getClass().equals(obj.getClass())) {
             return false;
         }
 
         AbstractDependencyManager that = (AbstractDependencyManager) obj;
         // exclude managedLocalPaths
         return Objects.equals(path, that.path)
                 && depth == that.depth
                 && Objects.equals(managedVersions, that.managedVersions)
                 && Objects.equals(managedScopes, that.managedScopes)
                 && Objects.equals(managedOptionals, that.managedOptionals)
                 && Objects.equals(managedExclusions, that.managedExclusions);
     }
 
     @Override
     public int hashCode() {
         return hashCode;
     }
 
     protected static class Key {
         private final Artifact artifact;
         private final int hashCode;
 
         Key(Artifact artifact) {
             this.artifact = artifact;
             this.hashCode = Objects.hash(
                     artifact.getArtifactId(), artifact.getGroupId(), artifact.getExtension(), artifact.getClassifier());
         }
 
         @Override
         public boolean equals(Object obj) {
             if (obj == this) {
                 return true;
             } else if (!(obj instanceof Key)) {
                 return false;
             }
             Key that = (Key) obj;
             return artifact.getArtifactId().equals(that.artifact.getArtifactId())
                     && artifact.getGroupId().equals(that.artifact.getGroupId())
                     && artifact.getExtension().equals(that.artifact.getExtension())
                     && artifact.getClassifier().equals(that.artifact.getClassifier());
         }
 
         @Override
         public int hashCode() {
             return hashCode;
         }
 
         @Override
         public String toString() {
             return String.valueOf(artifact);
         }
     }
 
     /**
      * Wrapper class for collection to memoize hash code.
      *
      * @param <T> The collection type.
      */
     protected static class Holder<T> {
         private final T value;
         private final int hashCode;
 
         Holder(T value) {
             this.value = requireNonNull(value);
             this.hashCode = Objects.hash(value);
         }
 
         public T getValue() {
             return value;
         }
 
         @Override
         public boolean equals(Object o) {
             if (!(o instanceof Holder)) {
                 return false;
             }
             Holder<?> holder = (Holder<?>) o;
             return Objects.equals(value, holder.value);
         }
 
         @Override
         public int hashCode() {
             return hashCode;
         }
     }
 }