/*
    * 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.model.merge;
  
  import java.util.ArrayList;
  import java.util.LinkedHashMap;
  import java.util.LinkedHashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import org.apache.maven.api.model.BuildBase;
  import org.apache.maven.api.model.CiManagement;
  import org.apache.maven.api.model.Dependency;
  import org.apache.maven.api.model.DeploymentRepository;
  import org.apache.maven.api.model.DistributionManagement;
  import org.apache.maven.api.model.Exclusion;
  import org.apache.maven.api.model.Extension;
  import org.apache.maven.api.model.InputLocation;
  import org.apache.maven.api.model.IssueManagement;
  import org.apache.maven.api.model.Model;
  import org.apache.maven.api.model.ModelBase;
  import org.apache.maven.api.model.Organization;
  import org.apache.maven.api.model.Plugin;
  import org.apache.maven.api.model.PluginExecution;
  import org.apache.maven.api.model.ReportPlugin;
  import org.apache.maven.api.model.ReportSet;
  import org.apache.maven.api.model.Repository;
  import org.apache.maven.api.model.RepositoryBase;
  import org.apache.maven.api.model.Scm;
  import org.apache.maven.api.model.Site;
  import org.apache.maven.model.v4.MavenMerger;
  import org.codehaus.plexus.util.StringUtils;
  
  /**
   * The domain-specific model merger for the Maven POM, overriding generic code from parent class when necessary with
   * more adapted algorithms.
   *
   * @author Benjamin Bentmann
   */
  public class MavenModelMerger extends MavenMerger {
  
      /**
       * The hint key for the child path adjustment used during inheritance for URL calculations.
       */
      public static final String CHILD_PATH_ADJUSTMENT = "child-path-adjustment";
  
      /**
       * The context key for the artifact id of the target model.
       */
      public static final String ARTIFACT_ID = "artifact-id";
  
      @Override
      protected Model mergeModel(Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
          context.put(ARTIFACT_ID, target.getArtifactId());
  
          return super.mergeModel(target, source, sourceDominant, context);
      }
  
      @Override
      protected void mergeModel_Name(
              Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
          String src = source.getName();
          if (src != null) {
              if (sourceDominant) {
                  builder.name(src);
                  builder.location("name", source.getLocation("name"));
              }
          }
      }
  
      @Override
      protected void mergeModel_Url(
              Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
          String src = source.getUrl();
          if (src != null) {
              if (sourceDominant) {
                  builder.url(src);
                  builder.location("url", source.getLocation("url"));
              } else if (target.getUrl() == null) {
                  builder.url(extrapolateChildUrl(src, source.isChildProjectUrlInheritAppendPath(), context));
                  builder.location("url", source.getLocation("url"));
              }
          }
     }
 
     /*
      * TODO: Whether the merge continues recursively into an existing node or not could be an option for the generated
      * merger
      */
     @Override
     protected void mergeModel_Organization(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         Organization src = source.getOrganization();
         if (src != null) {
             Organization tgt = target.getOrganization();
             if (tgt == null) {
                 builder.organization(src);
                 builder.location("organisation", source.getLocation("organisation"));
             }
         }
     }
 
     @Override
     protected void mergeModel_IssueManagement(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         IssueManagement src = source.getIssueManagement();
         if (src != null) {
             IssueManagement tgt = target.getIssueManagement();
             if (tgt == null) {
                 builder.issueManagement(src);
                 builder.location("issueManagement", source.getLocation("issueManagement"));
             }
         }
     }
 
     @Override
     protected void mergeModel_CiManagement(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         CiManagement src = source.getCiManagement();
         if (src != null) {
             CiManagement tgt = target.getCiManagement();
             if (tgt == null) {
                 builder.ciManagement(src);
                 builder.location("ciManagement", source.getLocation("ciManagement"));
             }
         }
     }
 
     @Override
     protected void mergeModel_ModelVersion(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         // neither inherited nor injected
     }
 
     @Override
     protected void mergeModel_ArtifactId(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         // neither inherited nor injected
     }
 
     @Override
     protected void mergeModel_Profiles(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         // neither inherited nor injected
     }
 
     @Override
     protected void mergeModel_Prerequisites(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         // neither inherited nor injected
     }
 
     @Override
     protected void mergeModel_Licenses(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         builder.licenses(target.getLicenses().isEmpty() ? source.getLicenses() : target.getLicenses());
     }
 
     @Override
     protected void mergeModel_Developers(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         builder.developers(target.getDevelopers().isEmpty() ? source.getDevelopers() : target.getDevelopers());
     }
 
     @Override
     protected void mergeModel_Contributors(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         builder.contributors(target.getContributors().isEmpty() ? source.getContributors() : target.getContributors());
     }
 
     @Override
     protected void mergeModel_MailingLists(
             Model.Builder builder, Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
         if (target.getMailingLists().isEmpty()) {
             builder.mailingLists(source.getMailingLists());
         }
     }
 
     @Override
     protected void mergeModelBase_Modules(
             ModelBase.Builder builder,
             ModelBase target,
             ModelBase source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         List<String> src = source.getModules();
         if (!src.isEmpty() && sourceDominant) {
             List<Integer> indices = new ArrayList<>();
             List<String> tgt = target.getModules();
             Set<String> excludes = new LinkedHashSet<>(tgt);
             List<String> merged = new ArrayList<>(tgt.size() + src.size());
             merged.addAll(tgt);
             for (int i = 0, n = tgt.size(); i < n; i++) {
                 indices.add(i);
             }
             for (int i = 0, n = src.size(); i < n; i++) {
                 String s = src.get(i);
                 if (!excludes.contains(s)) {
                     merged.add(s);
                     indices.add(~i);
                 }
             }
             builder.modules(merged);
             builder.location(
                     "modules",
                     InputLocation.merge(target.getLocation("modules"), source.getLocation("modules"), indices));
         }
     }
 
     /*
      * TODO: The order of the merged list could be controlled by an attribute in the model association: target-first,
      * source-first, dominant-first, recessive-first
      */
     @Override
     protected void mergeModelBase_Repositories(
             ModelBase.Builder builder,
             ModelBase target,
             ModelBase source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         List<Repository> src = source.getRepositories();
         if (!src.isEmpty()) {
             List<Repository> tgt = target.getRepositories();
             Map<Object, Repository> merged = new LinkedHashMap<>((src.size() + tgt.size()) * 2);
 
             List<Repository> dominant, recessive;
             if (sourceDominant) {
                 dominant = src;
                 recessive = tgt;
             } else {
                 dominant = tgt;
                 recessive = src;
             }
 
             for (Repository element : dominant) {
                 Object key = getRepositoryKey().apply(element);
                 merged.put(key, element);
             }
 
             for (Repository element : recessive) {
                 Object key = getRepositoryKey().apply(element);
                 if (!merged.containsKey(key)) {
                     merged.put(key, element);
                 }
             }
 
             builder.repositories(merged.values());
         }
     }
 
     @Override
     protected void mergeModelBase_PluginRepositories(
             ModelBase.Builder builder,
             ModelBase target,
             ModelBase source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         List<Repository> src = source.getPluginRepositories();
         if (!src.isEmpty()) {
             List<Repository> tgt = target.getPluginRepositories();
             Map<Object, Repository> merged = new LinkedHashMap<>((src.size() + tgt.size()) * 2);
 
             List<Repository> dominant, recessive;
             if (sourceDominant) {
                 dominant = src;
                 recessive = tgt;
             } else {
                 dominant = tgt;
                 recessive = src;
             }
 
             for (Repository element : dominant) {
                 Object key = getRepositoryKey().apply(element);
                 merged.put(key, element);
             }
 
             for (Repository element : recessive) {
                 Object key = getRepositoryKey().apply(element);
                 if (!merged.containsKey(key)) {
                     merged.put(key, element);
                 }
             }
 
             builder.pluginRepositories(merged.values());
         }
     }
 
     /*
      * TODO: Whether duplicates should be removed looks like an option for the generated merger.
      */
     @Override
     protected void mergeBuildBase_Filters(
             BuildBase.Builder builder,
             BuildBase target,
             BuildBase source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         List<String> src = source.getFilters();
         if (!src.isEmpty()) {
             List<String> tgt = target.getFilters();
             Set<String> excludes = new LinkedHashSet<>(tgt);
             List<String> merged = new ArrayList<>(tgt.size() + src.size());
             merged.addAll(tgt);
             for (String s : src) {
                 if (!excludes.contains(s)) {
                     merged.add(s);
                 }
             }
             builder.filters(merged);
         }
     }
 
     @Override
     protected void mergeBuildBase_Resources(
             BuildBase.Builder builder,
             BuildBase target,
             BuildBase source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         if (sourceDominant || target.getResources().isEmpty()) {
             super.mergeBuildBase_Resources(builder, target, source, sourceDominant, context);
         }
     }
 
     @Override
     protected void mergeBuildBase_TestResources(
             BuildBase.Builder builder,
             BuildBase target,
             BuildBase source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         if (sourceDominant || target.getTestResources().isEmpty()) {
             super.mergeBuildBase_TestResources(builder, target, source, sourceDominant, context);
         }
     }
 
     @Override
     protected void mergeDistributionManagement_Relocation(
             DistributionManagement.Builder builder,
             DistributionManagement target,
             DistributionManagement source,
             boolean sourceDominant,
             Map<Object, Object> context) {}
 
     @Override
     protected void mergeDistributionManagement_Repository(
             DistributionManagement.Builder builder,
             DistributionManagement target,
             DistributionManagement source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         DeploymentRepository src = source.getRepository();
         if (src != null) {
             DeploymentRepository tgt = target.getRepository();
             if (sourceDominant || tgt == null) {
                 tgt = DeploymentRepository.newInstance(false);
                 builder.repository(mergeDeploymentRepository(tgt, src, sourceDominant, context));
             }
         }
     }
 
     @Override
     protected void mergeDistributionManagement_SnapshotRepository(
             DistributionManagement.Builder builder,
             DistributionManagement target,
             DistributionManagement source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         DeploymentRepository src = source.getSnapshotRepository();
         if (src != null) {
             DeploymentRepository tgt = target.getSnapshotRepository();
             if (sourceDominant || tgt == null) {
                 tgt = DeploymentRepository.newInstance(false);
                 builder.snapshotRepository(mergeDeploymentRepository(tgt, src, sourceDominant, context));
             }
         }
     }
 
     @Override
     protected void mergeDistributionManagement_Site(
             DistributionManagement.Builder builder,
             DistributionManagement target,
             DistributionManagement source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         Site src = source.getSite();
         if (src != null) {
             Site tgt = target.getSite();
             if (tgt == null) {
                 tgt = Site.newBuilder(false).build();
             }
             Site.Builder sbuilder = Site.newBuilder(tgt);
             if (sourceDominant || tgt == null || isSiteEmpty(tgt)) {
                 mergeSite(sbuilder, tgt, src, sourceDominant, context);
             }
             super.mergeSite_ChildSiteUrlInheritAppendPath(sbuilder, tgt, src, sourceDominant, context);
             builder.site(sbuilder.build());
         }
     }
 
     @Override
     protected void mergeSite_ChildSiteUrlInheritAppendPath(
             Site.Builder builder, Site target, Site source, boolean sourceDominant, Map<Object, Object> context) {}
 
     protected boolean isSiteEmpty(Site site) {
         return StringUtils.isEmpty(site.getId())
                 && StringUtils.isEmpty(site.getName())
                 && StringUtils.isEmpty(site.getUrl());
     }
 
     @Override
     protected void mergeSite_Url(
             Site.Builder builder, Site target, Site source, boolean sourceDominant, Map<Object, Object> context) {
         String src = source.getUrl();
         if (src != null) {
             if (sourceDominant) {
                 builder.url(src);
                 builder.location("url", source.getLocation("url"));
             } else if (target.getUrl() == null) {
                 builder.url(extrapolateChildUrl(src, source.isChildSiteUrlInheritAppendPath(), context));
                 builder.location("url", source.getLocation("url"));
             }
         }
     }
 
     @Override
     protected void mergeScm_Url(
             Scm.Builder builder, Scm target, Scm source, boolean sourceDominant, Map<Object, Object> context) {
         String src = source.getUrl();
         if (src != null) {
             if (sourceDominant) {
                 builder.url(src);
                 builder.location("url", source.getLocation("url"));
             } else if (target.getUrl() == null) {
                 builder.url(extrapolateChildUrl(src, source.isChildScmUrlInheritAppendPath(), context));
                 builder.location("url", source.getLocation("url"));
             }
         }
     }
 
     @Override
     protected void mergeScm_Connection(
             Scm.Builder builder, Scm target, Scm source, boolean sourceDominant, Map<Object, Object> context) {
         String src = source.getConnection();
         if (src != null) {
             if (sourceDominant) {
                 builder.connection(src);
                 builder.location("connection", source.getLocation("connection"));
             } else if (target.getConnection() == null) {
                 builder.connection(extrapolateChildUrl(src, source.isChildScmConnectionInheritAppendPath(), context));
                 builder.location("connection", source.getLocation("connection"));
             }
         }
     }
 
     @Override
     protected void mergeScm_DeveloperConnection(
             Scm.Builder builder, Scm target, Scm source, boolean sourceDominant, Map<Object, Object> context) {
         String src = source.getDeveloperConnection();
         if (src != null) {
             if (sourceDominant) {
                 builder.developerConnection(src);
                 builder.location("developerConnection", source.getLocation("developerConnection"));
             } else if (target.getDeveloperConnection() == null) {
                 String e = extrapolateChildUrl(src, source.isChildScmDeveloperConnectionInheritAppendPath(), context);
                 builder.developerConnection(e);
                 builder.location("developerConnection", source.getLocation("developerConnection"));
             }
         }
     }
 
     @Override
     protected void mergePlugin_Executions(
             Plugin.Builder builder, Plugin target, Plugin source, boolean sourceDominant, Map<Object, Object> context) {
         List<PluginExecution> src = source.getExecutions();
         if (!src.isEmpty()) {
             List<PluginExecution> tgt = target.getExecutions();
             Map<Object, PluginExecution> merged = new LinkedHashMap<>((src.size() + tgt.size()) * 2);
 
             for (PluginExecution element : src) {
                 if (sourceDominant || (element.getInherited() != null ? element.isInherited() : source.isInherited())) {
                     Object key = getPluginExecutionKey().apply(element);
                     merged.put(key, element);
                 }
             }
 
             for (PluginExecution element : tgt) {
                 Object key = getPluginExecutionKey().apply(element);
                 PluginExecution existing = merged.get(key);
                 if (existing != null) {
                     element = mergePluginExecution(element, existing, sourceDominant, context);
                 }
                 merged.put(key, element);
             }
 
             builder.executions(merged.values());
         }
     }
 
     @Override
     protected void mergePluginExecution_Goals(
             PluginExecution.Builder builder,
             PluginExecution target,
             PluginExecution source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         List<String> src = source.getGoals();
         if (!src.isEmpty()) {
             List<String> tgt = target.getGoals();
             Set<String> excludes = new LinkedHashSet<>(tgt);
             List<String> merged = new ArrayList<>(tgt.size() + src.size());
             merged.addAll(tgt);
             for (String s : src) {
                 if (!excludes.contains(s)) {
                     merged.add(s);
                 }
             }
             builder.goals(merged);
         }
     }
 
     @Override
     protected void mergeReportPlugin_ReportSets(
             ReportPlugin.Builder builder,
             ReportPlugin target,
             ReportPlugin source,
             boolean sourceDominant,
             Map<Object, Object> context) {
         List<ReportSet> src = source.getReportSets();
         if (!src.isEmpty()) {
             List<ReportSet> tgt = target.getReportSets();
             Map<Object, ReportSet> merged = new LinkedHashMap<>((src.size() + tgt.size()) * 2);
 
             for (ReportSet rset : src) {
                 if (sourceDominant || (rset.getInherited() != null ? rset.isInherited() : source.isInherited())) {
                     Object key = getReportSetKey().apply(rset);
                     merged.put(key, rset);
                 }
             }
 
             for (ReportSet element : tgt) {
                 Object key = getReportSetKey().apply(element);
                 ReportSet existing = merged.get(key);
                 if (existing != null) {
                     mergeReportSet(element, existing, sourceDominant, context);
                 }
                 merged.put(key, element);
             }
 
             builder.reportSets(merged.values());
         }
     }
 
     @Override
     protected KeyComputer<Dependency> getDependencyKey() {
         return Dependency::getManagementKey;
     }
 
     @Override
     protected KeyComputer<Plugin> getPluginKey() {
         return Plugin::getKey;
     }
 
     @Override
     protected KeyComputer<PluginExecution> getPluginExecutionKey() {
         return PluginExecution::getId;
     }
 
     @Override
     protected KeyComputer<ReportPlugin> getReportPluginKey() {
         return ReportPlugin::getKey;
     }
 
     @Override
     protected KeyComputer<ReportSet> getReportSetKey() {
         return ReportSet::getId;
     }
 
     @Override
     protected KeyComputer<RepositoryBase> getRepositoryBaseKey() {
         return RepositoryBase::getId;
     }
 
     @Override
     protected KeyComputer<Extension> getExtensionKey() {
         return e -> e.getGroupId() + ':' + e.getArtifactId();
     }
 
     @Override
     protected KeyComputer<Exclusion> getExclusionKey() {
         return e -> e.getGroupId() + ':' + e.getArtifactId();
     }
 
     protected String extrapolateChildUrl(String parentUrl, boolean appendPath, Map<Object, Object> context) {
         return parentUrl;
     }
 }