/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2002, QOS.ch. All rights reserved.
    *
    * 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
    *
    *   or (per the licensee's choosing)
   *
   * 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.sift;
  
  import java.util.stream.Stream;
  
  import ch.qos.logback.core.Context;
  import ch.qos.logback.core.CoreConstants;
  import ch.qos.logback.core.model.AppenderModel;
  import ch.qos.logback.core.model.Model;
  import ch.qos.logback.core.model.SiftModel;
  import ch.qos.logback.core.model.processor.ModelHandlerBase;
  import ch.qos.logback.core.model.processor.ModelHandlerException;
  import ch.qos.logback.core.model.processor.ModelInterpretationContext;
  
  public class SiftModelHandler extends ModelHandlerBase {
      final static String ONE_AND_ONLY_ONE_URL = CoreConstants.CODES_URL + "#1andOnly1";
      
      public SiftModelHandler(Context context) {
          super(context);
      }
  
      static public SiftModelHandler makeInstance(Context context, ModelInterpretationContext ic) {
          return new SiftModelHandler(context);
      }
  
      @Override
      protected Class<SiftModel> getSupportedModelClass() {
          return SiftModel.class;
      }
      
      @SuppressWarnings("unchecked")
      @Override
      public void handle(ModelInterpretationContext mic, Model model) throws ModelHandlerException {
          
          SiftModel siftModel = (SiftModel) model;
          // don't let the processor handle sub-models
          siftModel.markAsSkipped();
          
          long appenderModelCount = computeAppenderModelCount(siftModel);
          
          if(appenderModelCount == 0) {
              String errMsg = "No nested appenders found within the <sift> element in SiftingAppender.";    
              addError(errMsg);
              return;
          }
          if(appenderModelCount > 1) {
              String errMsg = "Only and only one appender can be nested the <sift> element in SiftingAppender. See also " + ONE_AND_ONLY_ONE_URL;
              addError(errMsg);
              return;
          }
          
          
          Object o = mic.peekObject();
          if (o instanceof SiftingAppenderBase) {
              @SuppressWarnings("rawtypes")
              SiftingAppenderBase sa = (SiftingAppenderBase) o;
  
              String key = sa.getDiscriminatorKey();
              @SuppressWarnings("rawtypes")
              AppenderFactoryUsingSiftModel afusm = new AppenderFactoryUsingSiftModel(mic, siftModel, key);
           
              sa.setAppenderFactory(afusm);
              
          } else {
              addError("Unexpected object "+ o);
          }
      }
  
      private long computeAppenderModelCount(SiftModel siftModel) {
          Stream<Model> stream = siftModel.getSubModels().stream();
          long count = stream.filter((Model m) -> m instanceof AppenderModel).count();
          return count;
      }
  
  }