/*
    * 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.transform;
  
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.util.List;
  import java.util.Objects;
  import java.util.Optional;
  import java.util.function.Function;
  import java.util.regex.Pattern;
  
  import org.apache.maven.model.transform.pull.NodeBufferingParser;
  import org.codehaus.plexus.util.xml.pull.XmlPullParser;
  
  /**
   * <p>
   * Transforms relativePath to version.
   * We could decide to simply allow {@code <parent/>}, but let's require the GA for now for checking
   * This filter does NOT remove the relativePath (which is done by {@link RelativePathXMLFilter}, it will only
   * optionally include the version based on the path
   * </p>
   *
   * @author Robert Scholte
   * @author Guillaume Nodet
   * @since 4.0.0
   */
  class ParentXMLFilter extends NodeBufferingParser {
  
      private final Function<Path, Optional<RelativeProject>> relativePathMapper;
  
      private final Path projectPath;
  
      private static final Pattern S_FILTER = Pattern.compile("\\s+");
  
      /**
       * @param relativePathMapper
       */
      ParentXMLFilter(
              XmlPullParser parser, Function<Path, Optional<RelativeProject>> relativePathMapper, Path projectPath) {
          super(parser, "parent");
          this.relativePathMapper = relativePathMapper;
          this.projectPath = projectPath;
      }
  
      protected void process(List<Event> buffer) {
          String tagName = null;
          String groupId = null;
          String artifactId = null;
          String version = null;
          String relativePath = null;
          String whitespaceAfterParentStart = "";
          boolean hasVersion = false;
          boolean hasRelativePath = false;
          for (int i = 0; i < buffer.size(); i++) {
              Event event = buffer.get(i);
              if (event.event == START_TAG) {
                  tagName = event.name;
                  hasVersion |= "version".equals(tagName);
                  hasRelativePath |= "relativePath".equals(tagName);
              } else if (event.event == TEXT) {
                  if (S_FILTER.matcher(event.text).matches()) {
                      if (whitespaceAfterParentStart.isEmpty()) {
                          whitespaceAfterParentStart = event.text;
                      }
                  } else if ("groupId".equals(tagName)) {
                      groupId = nullSafeAppend(groupId, event.text);
                  } else if ("artifactId".equals(tagName)) {
                      artifactId = nullSafeAppend(artifactId, event.text);
                  } else if ("relativePath".equals(tagName)) {
                      relativePath = nullSafeAppend(relativePath, event.text);
                  } else if ("version".equals(tagName)) {
                      version = nullSafeAppend(version, event.text);
                  }
              } else if (event.event == END_TAG && "parent".equals(event.name)) {
                  Optional<RelativeProject> resolvedParent;
                  if (!hasVersion && (!hasRelativePath || relativePath != null)) {
                      Path relPath = Paths.get(Objects.toString(relativePath, "../pom.xml"));
                      resolvedParent = resolveRelativePath(relPath, groupId, artifactId);
                  } else {
                      resolvedParent = Optional.empty();
                  }
                 if (!hasVersion && resolvedParent.isPresent()) {
                     int pos = buffer.get(i - 1).event == TEXT ? i - 1 : i;
                     Event e = new Event();
                     e.event = TEXT;
                     e.text = whitespaceAfterParentStart;
                     buffer.add(pos++, e);
                     e = new Event();
                     e.event = START_TAG;
                     e.namespace = buffer.get(0).namespace;
                     e.prefix = buffer.get(0).prefix;
                     e.name = "version";
                     buffer.add(pos++, e);
                     e = new Event();
                     e.event = TEXT;
                     e.text = resolvedParent.get().getVersion();
                     buffer.add(pos++, e);
                     e = new Event();
                     e.event = END_TAG;
                     e.name = "version";
                     e.namespace = buffer.get(0).namespace;
                     e.prefix = buffer.get(0).prefix;
                     buffer.add(pos++, e);
                 }
                 break;
             }
         }
         buffer.forEach(this::pushEvent);
     }
 
     protected Optional<RelativeProject> resolveRelativePath(Path relativePath, String groupId, String artifactId) {
         Path pomPath = projectPath.resolve(relativePath);
         if (Files.isDirectory(pomPath)) {
             pomPath = pomPath.resolve("pom.xml");
         }
 
         Optional<RelativeProject> mappedProject = relativePathMapper.apply(pomPath.normalize());
 
         if (mappedProject.isPresent()) {
             RelativeProject project = mappedProject.get();
 
             if (Objects.equals(groupId, project.getGroupId()) && Objects.equals(artifactId, project.getArtifactId())) {
                 return mappedProject;
             }
         }
         return Optional.empty();
     }
 }