/*
    * 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.infra.route.context;
  
  import lombok.Getter;
  import org.apache.shardingsphere.infra.datanode.DataNode;
  import org.apache.shardingsphere.infra.rule.ShardingSphereRule;
  
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.LinkedHashMap;
  import java.util.LinkedHashSet;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  /**
   * Route context.
   */
  @Getter
  public final class RouteContext {
      
      private final Collection<Collection<DataNode>> originalDataNodes = new LinkedList<>();
      
      private final Collection<RouteUnit> routeUnits = new LinkedHashSet<>();
      
      private final Map<Class<? extends ShardingSphereRule>, RouteStageContext> routeStageContexts = new LinkedHashMap<>();
      
      /**
       * Judge is route for single database and table only or not.
       *
       * @return is route for single database and table only or not
       */
      public boolean isSingleRouting() {
          return 1 == routeUnits.size();
      }
      
      /**
       * Get actual data source names.
       *
       * @return actual data source names
       */
      public Collection<String> getActualDataSourceNames() {
          return routeUnits.stream().map(each -> each.getDataSourceMapper().getActualName()).collect(Collectors.toCollection(() -> new HashSet<>(routeUnits.size(), 1L)));
      }
      
      /**
       * Get actual tables groups.
       *
       * <p>
       * Actual tables in same group are belong one logic name.
       * </p>
       *
       * @param actualDataSourceName actual data source name
       * @param logicTableNames logic table names
       * @return actual table groups
       */
      public List<Set<String>> getActualTableNameGroups(final String actualDataSourceName, final Set<String> logicTableNames) {
          return logicTableNames.stream().map(each -> getActualTableNames(actualDataSourceName, each)).filter(each -> !each.isEmpty()).collect(Collectors.toList());
      }
      
      private Set<String> getActualTableNames(final String actualDataSourceName, final String logicTableName) {
          Set<String> result = new LinkedHashSet<>();
          for (RouteUnit each : routeUnits) {
              if (actualDataSourceName.equalsIgnoreCase(each.getDataSourceMapper().getActualName())) {
                  result.addAll(each.getActualTableNames(logicTableName));
              }
          }
          return result;
      }
      
      /**
       * Get map relationship between actual data source and logic tables.
       *
       * @param actualDataSourceNames actual data source names
       * @return map relationship between data source and logic tables
       */
      public Map<String, Set<String>> getDataSourceLogicTablesMap(final Collection<String> actualDataSourceNames) {
          Map<String, Set<String>> result = new HashMap<>(actualDataSourceNames.size(), 1F);
          for (String each : actualDataSourceNames) {
             Set<String> logicTableNames = getLogicTableNames(each);
             if (!logicTableNames.isEmpty()) {
                 result.put(each, logicTableNames);
             }
         }
         return result;
     }
     
     private Set<String> getLogicTableNames(final String actualDataSourceName) {
         Set<String> result = new HashSet<>();
         for (RouteUnit each : routeUnits) {
             if (actualDataSourceName.equalsIgnoreCase(each.getDataSourceMapper().getActualName())) {
                 result.addAll(each.getLogicTableNames());
             }
         }
         return result;
     }
     
     /**
      * Find table mapper.
      *
      * @param logicDataSourceName logic data source name
      * @param actualTableName actual table name
      * @return table mapper
      */
     public Optional<RouteMapper> findTableMapper(final String logicDataSourceName, final String actualTableName) {
         for (RouteUnit each : routeUnits) {
             Optional<RouteMapper> result = each.findTableMapper(logicDataSourceName, actualTableName);
             if (result.isPresent()) {
                 return result;
             }
         }
         return Optional.empty();
     }
     
     /**
      * Put route unit.
      *
      * @param dataSourceMapper database mapper
      * @param tableMappers table mapper collection
      */
     public void putRouteUnit(final RouteMapper dataSourceMapper, final Collection<RouteMapper> tableMappers) {
         Collection<RouteUnit> targets = getTargetRouteUnits(dataSourceMapper);
         if (targets.isEmpty()) {
             RouteUnit unit = new RouteUnit(dataSourceMapper, new LinkedHashSet<>());
             unit.getTableMappers().addAll(tableMappers);
             routeUnits.add(unit);
         } else {
             Collection<RouteUnit> toBeAdded = new LinkedList<>();
             Collection<RouteUnit> toBeRemoved = new LinkedList<>();
             for (RouteUnit each : targets) {
                 RouteUnit unit = new RouteUnit(dataSourceMapper, new LinkedHashSet<>());
                 unit.getTableMappers().addAll(each.getTableMappers());
                 unit.getTableMappers().addAll(tableMappers);
                 toBeAdded.add(unit);
                 toBeRemoved.add(each);
             }
             boolean success = routeUnits.addAll(toBeAdded);
             if (success) {
                 routeUnits.removeAll(toBeRemoved);
             }
         }
     }
     
     private Collection<RouteUnit> getTargetRouteUnits(final RouteMapper dataSourceMapper) {
         Collection<RouteUnit> result = new LinkedList<>();
         for (RouteUnit each : routeUnits) {
             if (each.getDataSourceMapper().equals(dataSourceMapper)) {
                 result.add(each);
             }
         }
         return result;
     }
     
     /**
      * Judge whether route context contains table sharding or not.
      * 
      * @return whether route context contains table sharding or not
      */
     public boolean containsTableSharding() {
         for (RouteUnit each : routeUnits) {
             for (RouteMapper tableMapper : each.getTableMappers()) {
                 if (!tableMapper.getActualName().equals(tableMapper.getLogicName())) {
                     return true;
                 }
             }
         }
         return false;
     }
 }