/*
    * 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.sharding.cache.route.cache;
  
  import lombok.AccessLevel;
  import lombok.RequiredArgsConstructor;
  import org.apache.shardingsphere.infra.datanode.DataNode;
  import org.apache.shardingsphere.infra.route.context.RouteContext;
  import org.apache.shardingsphere.infra.route.context.RouteStageContext;
  import org.apache.shardingsphere.infra.route.context.RouteUnit;
  import org.apache.shardingsphere.infra.rule.ShardingSphereRule;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Map;
  import java.util.Optional;
  
  /**
   * Value of sharding route cache.
   */
  @RequiredArgsConstructor(access = AccessLevel.PRIVATE)
  public final class ShardingRouteCacheValue {
      
      private final boolean cacheable;
      
      private final RouteContext cachedRouteContext;
      
      public ShardingRouteCacheValue(final RouteContext routeContext) {
          this(null != routeContext, routeContext);
      }
      
      /**
       * Get cached route context.
       *
       * @return optional cached route context
       */
      public Optional<RouteContext> getCachedRouteContext() {
          return cacheable ? Optional.of(deepCopyRouteContext()) : Optional.empty();
      }
      
      private RouteContext deepCopyRouteContext() {
          RouteContext result = new RouteContext();
          result.getOriginalDataNodes().addAll(deepCopyOriginalDataNodes());
          result.getRouteUnits().addAll(deepCopyRouteUnits());
          result.getRouteStageContexts().putAll(deepCopyRouteStageContext());
          return result;
      }
      
      private Collection<Collection<DataNode>> deepCopyOriginalDataNodes() {
          Collection<Collection<DataNode>> result = new ArrayList<>(cachedRouteContext.getOriginalDataNodes().size());
          for (Collection<DataNode> eachDataNodes : cachedRouteContext.getOriginalDataNodes()) {
              Collection<DataNode> eachResult = new ArrayList<>(eachDataNodes.size());
              // TODO This could be simplified if all fields of DataNode were immutable
              for (DataNode each : eachDataNodes) {
                  DataNode copiedDataNode = new DataNode(each.getDataSourceName(), each.getTableName());
                  copiedDataNode.setSchemaName(each.getSchemaName());
                  eachResult.add(copiedDataNode);
              }
              result.add(eachResult);
          }
          return result;
      }
      
      private Collection<RouteUnit> deepCopyRouteUnits() {
          Collection<RouteUnit> result = new ArrayList<>(cachedRouteContext.getRouteUnits().size());
          for (RouteUnit each : cachedRouteContext.getRouteUnits()) {
              result.add(new RouteUnit(each.getDataSourceMapper(), new ArrayList<>(each.getTableMappers())));
          }
          return result;
      }
      
      private Map<Class<? extends ShardingSphereRule>, ? extends RouteStageContext> deepCopyRouteStageContext() {
          // TODO Implements deep copy for route stage contexts
          return cachedRouteContext.getRouteStageContexts();
      }
  }