/**
    * This file Copyright (c) 2017-2018 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.config.source.yaml;
  
  import info.magnolia.config.source.yaml.construct.IncludeYamlFile;
  import info.magnolia.config.source.yaml.construct.MgnlYamlConstruct;
  import info.magnolia.config.source.yaml.dependency.YamlConfigurationDependency;
  import info.magnolia.resourceloader.Resource;
  
  import java.util.HashSet;
  import java.util.Set;
  
  import org.yaml.snakeyaml.constructor.Construct;
  import org.yaml.snakeyaml.constructor.Constructor;
  import org.yaml.snakeyaml.nodes.MappingNode;
  import org.yaml.snakeyaml.nodes.Node;
  import org.yaml.snakeyaml.nodes.ScalarNode;
  import org.yaml.snakeyaml.nodes.SequenceNode;
  import org.yaml.snakeyaml.nodes.Tag;
  
  /**
   * Magnolia-specific extension of {@link Constructor SnakeYAML constructor}.
   * Provides simple API for registering custom constructs bound to tags and tag prefixes. Exposes the factory method for producing the
   * {@link Construct constructs} by the node types ({@link MgnlYamlConstructor#getConstructByNodeType(Node)}). Finally, {@link MgnlYamlConstructor}
   * allows to aggregate the dependencies encountered during YAML parsing (other YAML files, definitions etc).
   */
  public class MgnlYamlConstructor extends Constructor {
  
      private final YamlConfigurationDependencyAggregator dependencyAggregator;
  
      MgnlYamlConstructor(YamlReader yamlReader, Resource baseResource, YamlConfigurationDependencyAggregator dependencyAggregator) {
          this.dependencyAggregator = dependencyAggregator;
          registerConstruct(IncludeYamlFile.TAG, new IncludeYamlFile(yamlReader, baseResource.getOrigin(), problem -> {}));
      }
  
      void registerConstruct(String tag, Construct construct) {
          if (construct instanceof MgnlYamlConstruct) {
              ((MgnlYamlConstruct) construct).setConstructor(this);
          }
          yamlConstructors.put(new Tag(tag), construct);
      }
  
      void registerMultiConstruct(String tagPrefix, Construct construct) {
          if (construct instanceof MgnlYamlConstruct) {
              ((MgnlYamlConstruct) construct).setConstructor(this);
          }
          yamlMultiConstructors.put(tagPrefix, construct);
      }
  
      public Construct getConstructByNodeType(Node node) {
          // (re-)initialise base construct
          // if there's an extension tag present, YAML will get confused about the actual expected type
          // of the node (it'll assume some abstract 'object')
          if (node instanceof MappingNode) {
              return new ConstructYamlMap();
          } else if (node instanceof SequenceNode) {
              return new ConstructYamlSeq();
          }
  
          return new ConstructScalar() {
              @Override
              public Object construct(Node n) {
                  return ((ScalarNode) n).getValue();
              }
          };
      }
  
      public YamlConfigurationDependencyAggregator getDependencyAggregator() {
         return dependencyAggregator;
     }
 
     /**
      * Simple aggregator class which allows to collect a set of {@link YamlConfigurationDependency} instances.
      */
     public static class YamlConfigurationDependencyAggregator {
 
         private Set<YamlConfigurationDependency> dependencies = new HashSet<>();
 
         YamlConfigurationDependencyAggregator() {}
 
         public void addDependency(YamlConfigurationDependency dependency) {
             this.dependencies.add(dependency);
         }
 
         public Set<YamlConfigurationDependency> getDependencies() {
             return this.dependencies;
         }
 
     }
 }