/*
    * 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.inheritance;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.maven.api.model.InputLocation;
  import org.apache.maven.api.model.Model;
  import org.apache.maven.api.model.ModelBase;
  import org.apache.maven.api.model.Plugin;
  import org.apache.maven.api.model.PluginContainer;
  import org.apache.maven.api.model.ReportPlugin;
  import org.apache.maven.api.model.Reporting;
  import org.apache.maven.model.building.ModelBuildingRequest;
  import org.apache.maven.model.building.ModelProblemCollector;
  import org.apache.maven.model.merge.MavenModelMerger;
  import org.codehaus.plexus.util.StringUtils;
  
  /**
   * Handles inheritance of model values.
   *
   * @author Benjamin Bentmann
   */
  @SuppressWarnings({"checkstyle:methodname"})
  @Named
  @Singleton
  public class DefaultInheritanceAssembler implements InheritanceAssembler {
  
      private InheritanceModelMerger merger = new InheritanceModelMerger();
  
      private static final String CHILD_DIRECTORY = "child-directory";
  
      private static final String CHILD_DIRECTORY_PROPERTY = "project.directory";
  
      @Override
      public Model assembleModelInheritance(
              Model child, Model parent, ModelBuildingRequest request, ModelProblemCollector problems) {
          Map<Object, Object> hints = new HashMap<>();
          String childPath = child.getProperties().getOrDefault(CHILD_DIRECTORY_PROPERTY, child.getArtifactId());
          hints.put(CHILD_DIRECTORY, childPath);
          hints.put(MavenModelMerger.CHILD_PATH_ADJUSTMENT, getChildPathAdjustment(child, parent, childPath));
          return merger.merge(child, parent, false, hints);
      }
  
      /**
       * Calculates the relative path from the base directory of the parent to the parent directory of the base directory
       * of the child. The general idea is to adjust inherited URLs to match the project layout (in SCM).
       *
       * <p>This calculation is only a heuristic based on our conventions.
       * In detail, the algo relies on the following assumptions: <ul>
       * <li>The parent uses aggregation and refers to the child via the modules section</li>
       * <li>The module path to the child is considered to
       * point at the POM rather than its base directory if the path ends with ".xml" (ignoring case)</li>
       * <li>The name of the child's base directory matches the artifact id of the child.</li>
       * </ul>
       * Note that for the sake of independence from the user
       * environment, the filesystem is intentionally not used for the calculation.</p>
       *
       * @param child The child model, must not be <code>null</code>.
       * @param parent The parent model, may be <code>null</code>.
       * @param childDirectory The directory defined in child model, may be <code>null</code>.
       * @return The path adjustment, can be empty but never <code>null</code>.
       */
      private String getChildPathAdjustment(Model child, Model parent, String childDirectory) {
          String adjustment = "";
  
          if (parent != null) {
              String childName = child.getArtifactId();
  
              /*
               * This logic (using filesystem, against wanted independence from the user environment) exists only for the
               * sake of backward-compat with 2.x (MNG-5000). In general, it is wrong to
               * base URL inheritance on the module directory names as this information is unavailable for POMs in the
               * repository. In other words, modules where artifactId != moduleDirName will see different effective URLs
               * depending on how the model was constructed (from filesystem or from repository).
               */
             if (child.getProjectDirectory() != null) {
                 childName = child.getProjectDirectory().getFileName().toString();
             }
 
             for (String module : parent.getModules()) {
                 module = module.replace('\\', '/');
 
                 if (module.regionMatches(true, module.length() - 4, ".xml", 0, 4)) {
                     module = module.substring(0, module.lastIndexOf('/') + 1);
                 }
 
                 String moduleName = module;
                 if (moduleName.endsWith("/")) {
                     moduleName = moduleName.substring(0, moduleName.length() - 1);
                 }
 
                 int lastSlash = moduleName.lastIndexOf('/');
 
                 moduleName = moduleName.substring(lastSlash + 1);
 
                 if ((moduleName.equals(childName) || (moduleName.equals(childDirectory))) && lastSlash >= 0) {
                     adjustment = module.substring(0, lastSlash);
                     break;
                 }
             }
         }
 
         return adjustment;
     }
 
     /**
      * InheritanceModelMerger
      */
     protected static class InheritanceModelMerger extends MavenModelMerger {
 
         @Override
         protected String extrapolateChildUrl(String parentUrl, boolean appendPath, Map<Object, Object> context) {
             Object childDirectory = context.get(CHILD_DIRECTORY);
             Object childPathAdjustment = context.get(CHILD_PATH_ADJUSTMENT);
 
             if (StringUtils.isBlank(parentUrl)
                     || childDirectory == null
                     || childPathAdjustment == null
                     || !appendPath) {
                 return parentUrl;
             }
 
             // append childPathAdjustment and childDirectory to parent url
             return appendPath(parentUrl, childDirectory.toString(), childPathAdjustment.toString());
         }
 
         private String appendPath(String parentUrl, String childPath, String pathAdjustment) {
             StringBuilder url = new StringBuilder(parentUrl.length()
                     + pathAdjustment.length()
                     + childPath.length()
                     + ((pathAdjustment.length() == 0) ? 1 : 2));
 
             url.append(parentUrl);
             concatPath(url, pathAdjustment);
             concatPath(url, childPath);
 
             return url.toString();
         }
 
         private void concatPath(StringBuilder url, String path) {
             if (path.length() > 0) {
                 boolean initialUrlEndsWithSlash = url.charAt(url.length() - 1) == '/';
                 boolean pathStartsWithSlash = path.charAt(0) == '/';
 
                 if (pathStartsWithSlash) {
                     if (initialUrlEndsWithSlash) {
                         // 1 extra '/' to remove
                         url.setLength(url.length() - 1);
                     }
                 } else if (!initialUrlEndsWithSlash) {
                     // add missing '/' between url and path
                     url.append('/');
                 }
 
                 url.append(path);
 
                 // ensure resulting url ends with slash if initial url was
                 if (initialUrlEndsWithSlash && !path.endsWith("/")) {
                     url.append('/');
                 }
             }
         }
 
         @Override
         protected void mergeModelBase_Properties(
                 ModelBase.Builder builder,
                 ModelBase target,
                 ModelBase source,
                 boolean sourceDominant,
                 Map<Object, Object> context) {
             Map<String, String> merged = new HashMap<>();
             if (sourceDominant) {
                 merged.putAll(target.getProperties());
                 putAll(merged, source.getProperties(), CHILD_DIRECTORY_PROPERTY);
             } else {
                 putAll(merged, source.getProperties(), CHILD_DIRECTORY_PROPERTY);
                 merged.putAll(target.getProperties());
             }
             builder.properties(merged);
             builder.location(
                     "properties",
                     InputLocation.merge(
                             target.getLocation("properties"), source.getLocation("properties"), sourceDominant));
         }
 
         private void putAll(Map<String, String> s, Map<String, String> t, Object excludeKey) {
             for (Map.Entry<String, String> e : t.entrySet()) {
                 if (!e.getKey().equals(excludeKey)) {
                     s.put(e.getKey(), e.getValue());
                 }
             }
         }
 
         @Override
         protected void mergePluginContainer_Plugins(
                 PluginContainer.Builder builder,
                 PluginContainer target,
                 PluginContainer source,
                 boolean sourceDominant,
                 Map<Object, Object> context) {
             List<Plugin> src = source.getPlugins();
             if (!src.isEmpty()) {
                 List<Plugin> tgt = target.getPlugins();
                 Map<Object, Plugin> master = new LinkedHashMap<>(src.size() * 2);
 
                 for (Plugin element : src) {
                     if (element.isInherited() || !element.getExecutions().isEmpty()) {
                         // NOTE: Enforce recursive merge to trigger merging/inheritance logic for executions
                         Plugin plugin = Plugin.newInstance(false);
                         plugin = mergePlugin(plugin, element, sourceDominant, context);
 
                         Object key = getPluginKey().apply(plugin);
 
                         master.put(key, plugin);
                     }
                 }
 
                 Map<Object, List<Plugin>> predecessors = new LinkedHashMap<>();
                 List<Plugin> pending = new ArrayList<>();
                 for (Plugin element : tgt) {
                     Object key = getPluginKey().apply(element);
                     Plugin existing = master.get(key);
                     if (existing != null) {
                         element = mergePlugin(element, existing, sourceDominant, context);
 
                         master.put(key, element);
 
                         if (!pending.isEmpty()) {
                             predecessors.put(key, pending);
                             pending = new ArrayList<>();
                         }
                     } else {
                         pending.add(element);
                     }
                 }
 
                 List<Plugin> result = new ArrayList<>(src.size() + tgt.size());
                 for (Map.Entry<Object, Plugin> entry : master.entrySet()) {
                     List<Plugin> pre = predecessors.get(entry.getKey());
                     if (pre != null) {
                         result.addAll(pre);
                     }
                     result.add(entry.getValue());
                 }
                 result.addAll(pending);
 
                 builder.plugins(result);
             }
         }
 
         @Override
         protected Plugin mergePlugin(
                 Plugin target, Plugin source, boolean sourceDominant, Map<Object, Object> context) {
             Plugin.Builder builder = Plugin.newBuilder(target);
             if (source.isInherited()) {
                 mergeConfigurationContainer(builder, target, source, sourceDominant, context);
             }
             mergePlugin_GroupId(builder, target, source, sourceDominant, context);
             mergePlugin_ArtifactId(builder, target, source, sourceDominant, context);
             mergePlugin_Version(builder, target, source, sourceDominant, context);
             mergePlugin_Extensions(builder, target, source, sourceDominant, context);
             mergePlugin_Executions(builder, target, source, sourceDominant, context);
             mergePlugin_Dependencies(builder, target, source, sourceDominant, context);
             return builder.build();
         }
 
         @Override
         protected void mergeReporting_Plugins(
                 Reporting.Builder builder,
                 Reporting target,
                 Reporting source,
                 boolean sourceDominant,
                 Map<Object, Object> context) {
             List<ReportPlugin> src = source.getPlugins();
             if (!src.isEmpty()) {
                 List<ReportPlugin> tgt = target.getPlugins();
                 Map<Object, ReportPlugin> merged = new LinkedHashMap<>((src.size() + tgt.size()) * 2);
 
                 for (ReportPlugin element : src) {
                     if (element.isInherited()) {
                         // NOTE: Enforce recursive merge to trigger merging/inheritance logic for executions as well
                         ReportPlugin plugin = ReportPlugin.newInstance(false);
                         plugin = mergeReportPlugin(plugin, element, sourceDominant, context);
 
                         merged.put(getReportPluginKey().apply(element), plugin);
                     }
                 }
 
                 for (ReportPlugin element : tgt) {
                     Object key = getReportPluginKey().apply(element);
                     ReportPlugin existing = merged.get(key);
                     if (existing != null) {
                         element = mergeReportPlugin(element, existing, sourceDominant, context);
                     }
                     merged.put(key, element);
                 }
 
                 builder.plugins(merged.values());
             }
         }
     }
 }