/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2022, QOS.ch. All rights reserved.
    * <p>
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    * <p>
    * or (per the licensee's choosing)
   * <p>
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.core.joran.sanity;
  
  import ch.qos.logback.core.model.AppenderModel;
  import ch.qos.logback.core.model.Model;
  import ch.qos.logback.core.spi.ContextAwareBase;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.stream.Collectors;
  
  public class AppenderWithinAppenderSanityChecker extends ContextAwareBase implements SanityChecker  {
  
      static public String NESTED_APPENDERS_WARNING = "As of logback version 1.3, nested appenders are not allowed.";
  
      @Override
      public void check(Model model) {
          if (model == null)
              return;
  
          List<Model> appenderModels = new ArrayList<>();
          deepFindAllModelsOfType(AppenderModel.class, appenderModels, model);
  
          List<Pair<Model, Model>> nestedPairs = deepFindNestedSubModelsOfType(AppenderModel.class, appenderModels);
  
          List<Pair<Model, Model>> filteredNestedPairs = nestedPairs.stream().filter(pair -> !isSiftingAppender(pair.first)).collect(Collectors.toList());
  
          if(filteredNestedPairs.isEmpty()) {
              return;
          }
          addWarn(NESTED_APPENDERS_WARNING);
          for(Pair<Model, Model> pair: filteredNestedPairs) {
              addWarn("Appender at line "+pair.first.getLineNumber() + " contains a nested appender at line "+pair.second.getLineNumber());
          }
      }
  
      private boolean isSiftingAppender(Model first) {
          if(first instanceof  AppenderModel) {
              AppenderModel appenderModel = (AppenderModel) first;
              String classname = appenderModel.getClassName();
              if(classname == null)
                  return false;
              return appenderModel.getClassName().contains("SiftingAppender");
          }
          return false;
      }
  
  }