/*
    * 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.shardingsphere.shadow.route.engine;
  
  import org.apache.shardingsphere.infra.route.context.RouteContext;
  import org.apache.shardingsphere.infra.route.context.RouteMapper;
  import org.apache.shardingsphere.infra.route.context.RouteUnit;
  import org.apache.shardingsphere.shadow.rule.ShadowRule;
  
  import java.util.Collection;
  import java.util.LinkedList;
  import java.util.Map;
  import java.util.Optional;
  
  /**
   * Shadow route engine.
   */
  public interface ShadowRouteEngine {
      
      /**
       * Route.
       *
       * @param routeContext route context
       * @param rule shadow rule
       */
      void route(RouteContext routeContext, ShadowRule rule);
      
      /**
       * Decorate route context.
       *
       * @param routeContext route context to be decorated
       * @param rule shadow rule
       * @param shadowDataSourceMappings shadow data source mappings
       */
      default void decorateRouteContext(final RouteContext routeContext, final ShadowRule rule, final Map<String, String> shadowDataSourceMappings) {
          Collection<RouteUnit> toBeRemovedRouteUnit = new LinkedList<>();
          Collection<RouteUnit> toBeAddedRouteUnit = new LinkedList<>();
          for (RouteUnit each : routeContext.getRouteUnits()) {
              String logicName = each.getDataSourceMapper().getLogicName();
              String actualName = each.getDataSourceMapper().getActualName();
              Optional<String> sourceDataSourceName = rule.getSourceDataSourceName(actualName);
              if (sourceDataSourceName.isPresent()) {
                  String shadowDataSourceName = shadowDataSourceMappings.get(sourceDataSourceName.get());
                  toBeRemovedRouteUnit.add(each);
                  toBeAddedRouteUnit.add(null == shadowDataSourceName
                          ? new RouteUnit(new RouteMapper(logicName, sourceDataSourceName.get()), each.getTableMappers())
                          : new RouteUnit(new RouteMapper(logicName, shadowDataSourceName), each.getTableMappers()));
              }
          }
          routeContext.getRouteUnits().removeAll(toBeRemovedRouteUnit);
          routeContext.getRouteUnits().addAll(toBeAddedRouteUnit);
      }
  }