content: /*
   * Copyright 2013-2023 the original author or authors.
   *
   * Licensed 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
   *
   *      https://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 com.alibaba.cloud.nacos.annotation;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.LinkedHashMap;
  import java.util.Map;
  
  import com.alibaba.nacos.api.config.ConfigChangeItem;
  import com.alibaba.nacos.api.exception.NacosException;
  import com.alibaba.nacos.api.exception.runtime.NacosRuntimeException;
  import com.alibaba.nacos.client.config.impl.YmlChangeParser;
  import com.alibaba.nacos.common.utils.StringUtils;
  import org.yaml.snakeyaml.LoaderOptions;
  import org.yaml.snakeyaml.Yaml;
  import org.yaml.snakeyaml.composer.ComposerException;
  import org.yaml.snakeyaml.constructor.SafeConstructor;
  import org.yaml.snakeyaml.error.MarkedYAMLException;
  
  public class ScaYamlConfigChangeParser extends YmlChangeParser {
  	private static final String INVALID_CONSTRUCTOR_ERROR_INFO = "could not determine a constructor for the tag";
  
  	public ScaYamlConfigChangeParser() {
  		super();
  	}
  
  	@Override
  	public Map<String, ConfigChangeItem> doParse(String oldContent, String newContent, String type) {
  		Map<String, Object> oldMap = Collections.emptyMap();
  		Map<String, Object> newMap = Collections.emptyMap();
  		try {
  			Yaml yaml = new Yaml(new SafeConstructor(new LoaderOptions()));
  			if (StringUtils.isNotBlank(oldContent)) {
  				oldMap = yaml.load(oldContent);
  				oldMap = getFlattenedMap(oldMap);
  			}
  			if (StringUtils.isNotBlank(newContent)) {
  				newMap = yaml.load(newContent);
  				newMap = getFlattenedMap(newMap);
  			}
  		}
  		catch (MarkedYAMLException e) {
  			handleYamlException(e);
  		}
  
  		return filterChangeData(oldMap, newMap);
  	}
  
  	private void handleYamlException(MarkedYAMLException e) {
  		if (e.getMessage().startsWith(INVALID_CONSTRUCTOR_ERROR_INFO) || e instanceof ComposerException) {
  			throw new NacosRuntimeException(NacosException.INVALID_PARAM,
  					"AbstractConfigChangeListener only support basic java data type for yaml. If you want to listen "
  							+ "key changes for custom classes, please use `Listener` to listener whole yaml configuration and parse it by yourself.",
  					e);
  		}
  		throw e;
  	}
  
  	private Map<String, Object> getFlattenedMap(Map<String, Object> source) {
  		Map<String, Object> result = new LinkedHashMap<>(128);
  		buildFlattenedMap(result, source, null);
  		return result;
  	}
  
  	private void buildFlattenedMap(Map<String, Object> result, Map<String, Object> source, String path) {
  		for (Iterator<Map.Entry<String, Object>> itr = source.entrySet().iterator(); itr.hasNext(); ) {
  			Map.Entry<String, Object> e = itr.next();
  			String key = String.valueOf(e.getKey());
  			if (StringUtils.isNotBlank(path)) {
  				if (key.startsWith("[")) {
  					key = path + key;
  				}
  				else {
  					key = path + '.' + key;
  				}
  			}
  			if (e.getValue() instanceof String) {
  				result.put(key, e.getValue());
  			}
  			else if (e.getValue() instanceof Map) {
  				@SuppressWarnings("unchecked") Map<String, Object> map = (Map<String, Object>) e.getValue();
  				buildFlattenedMap(result, map, key);
  			}
  			else if (e.getValue() instanceof Collection) {
  				@SuppressWarnings("unchecked") Collection<Object> collection = (Collection<Object>) e.getValue();
  				if (collection.isEmpty()) {
  					result.put(key, "");
  				}
  				else {
  					int count = 0;
  					for (Object object : collection) {
  						buildFlattenedMap(result, Collections.singletonMap("[" + (count++) + "]", object), key);
  					}
  				}
  			}
  			else {
  				result.put(key, (e.getValue() != null ? e.getValue() : ""));
  			}
  		}
  	}
  
  }
  