/*
    * 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.route.engine.type;
  
  import lombok.AccessLevel;
  import lombok.NoArgsConstructor;
  import org.apache.shardingsphere.infra.binder.context.statement.SQLStatementContext;
  import org.apache.shardingsphere.infra.config.props.ConfigurationProperties;
  import org.apache.shardingsphere.infra.hint.HintValueContext;
  import org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabase;
  import org.apache.shardingsphere.infra.session.connection.ConnectionContext;
  import org.apache.shardingsphere.infra.session.query.QueryContext;
  import org.apache.shardingsphere.sharding.route.engine.condition.ShardingCondition;
  import org.apache.shardingsphere.sharding.route.engine.condition.ShardingConditions;
  import org.apache.shardingsphere.sharding.route.engine.type.broadcast.ShardingDatabaseBroadcastRouteEngine;
  import org.apache.shardingsphere.sharding.route.engine.type.broadcast.ShardingInstanceBroadcastRouteEngine;
  import org.apache.shardingsphere.sharding.route.engine.type.broadcast.ShardingTableBroadcastRouteEngine;
  import org.apache.shardingsphere.sharding.route.engine.type.complex.ShardingComplexRouteEngine;
  import org.apache.shardingsphere.sharding.route.engine.type.ignore.ShardingIgnoreRouteEngine;
  import org.apache.shardingsphere.sharding.route.engine.type.standard.ShardingStandardRouteEngine;
  import org.apache.shardingsphere.sharding.route.engine.type.unicast.ShardingUnicastRouteEngine;
  import org.apache.shardingsphere.sharding.rule.ShardingRule;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.SQLStatement;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.attribute.type.CursorSQLStatementAttribute;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.attribute.type.TableBroadcastRouteSQLStatementAttribute;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.type.dal.DALStatement;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.type.dcl.DCLStatement;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.type.ddl.DDLStatement;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.type.ddl.procedure.AlterProcedureStatement;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.type.ddl.procedure.CreateProcedureStatement;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.type.ddl.procedure.DropProcedureStatement;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.type.dml.DMLStatement;
  
  import java.util.Collection;
  
  /**
   * Sharding routing engine factory.
   */
  @NoArgsConstructor(access = AccessLevel.PRIVATE)
  public final class ShardingRouteEngineFactory {
      
      /**
       * Create new instance of routing engine.
       *
       * @param rule sharding rule
       * @param database database
       * @param queryContext query context
       * @param shardingConditions shardingConditions
       * @param logicTableNames logic table names
       * @param props ShardingSphere properties
       * @return created instance
       */
      public static ShardingRouteEngine newInstance(final ShardingRule rule, final ShardingSphereDatabase database, final QueryContext queryContext,
                                                    final ShardingConditions shardingConditions, final Collection<String> logicTableNames, final ConfigurationProperties props) {
          SQLStatementContext sqlStatementContext = queryContext.getSqlStatementContext();
          SQLStatement sqlStatement = sqlStatementContext.getSqlStatement();
          if (sqlStatement instanceof DDLStatement) {
              return queryContext.getSqlStatementContext().getSqlStatement().getAttributes().findAttribute(CursorSQLStatementAttribute.class).isPresent()
                      ? getCursorRouteEngine(rule, sqlStatementContext, queryContext.getHintValueContext(), shardingConditions, logicTableNames, props)
                      : getDDLRouteEngine(database, sqlStatementContext, logicTableNames);
          }
          if (sqlStatement instanceof DALStatement) {
              return getDALRouteEngine(database, sqlStatementContext, queryContext.getConnectionContext(), logicTableNames);
          }
          if (sqlStatement instanceof DCLStatement) {
              return getDCLRouteEngine(database, sqlStatementContext, logicTableNames);
          }
          return getDQLRouteEngine(rule, sqlStatementContext, queryContext, shardingConditions, logicTableNames, props);
      }
      
      private static ShardingRouteEngine getDDLRouteEngine(final ShardingSphereDatabase database, final SQLStatementContext sqlStatementContext, final Collection<String> logicTableNames) {
          SQLStatement sqlStatement = sqlStatementContext.getSqlStatement();
          boolean procedureStatement = sqlStatement instanceof CreateProcedureStatement || sqlStatement instanceof AlterProcedureStatement || sqlStatement instanceof DropProcedureStatement;
          if (procedureStatement) {
              return new ShardingDatabaseBroadcastRouteEngine();
          }
          return new ShardingTableBroadcastRouteEngine(database, sqlStatementContext, logicTableNames);
      }
      
      private static ShardingRouteEngine getCursorRouteEngine(final ShardingRule rule, final SQLStatementContext sqlStatementContext,
                                                              final HintValueContext hintValueContext, final ShardingConditions shardingConditions, final Collection<String> logicTableNames,
                                                              final ConfigurationProperties props) {
          boolean allBindingTables = logicTableNames.size() > 1 && rule.isBindingTablesUseShardingColumnsJoin(sqlStatementContext, logicTableNames);
          if (isShardingStandardQuery(rule, logicTableNames, allBindingTables)) {
             return new ShardingStandardRouteEngine(getLogicTableName(shardingConditions, logicTableNames), shardingConditions, sqlStatementContext, hintValueContext, props);
         }
         return new ShardingIgnoreRouteEngine();
     }
     
     private static ShardingRouteEngine getDALRouteEngine(final ShardingSphereDatabase database, final SQLStatementContext sqlStatementContext,
                                                          final ConnectionContext connectionContext, final Collection<String> logicTableNames) {
         if (sqlStatementContext.getSqlStatement().getAttributes().findAttribute(TableBroadcastRouteSQLStatementAttribute.class).isPresent()) {
             return new ShardingTableBroadcastRouteEngine(database, sqlStatementContext, logicTableNames);
         }
         return new ShardingUnicastRouteEngine(sqlStatementContext, logicTableNames, connectionContext);
     }
     
     private static ShardingRouteEngine getDCLRouteEngine(final ShardingSphereDatabase database, final SQLStatementContext sqlStatementContext, final Collection<String> logicTableNames) {
         return isDCLForSingleTable(sqlStatementContext) ? new ShardingTableBroadcastRouteEngine(database, sqlStatementContext, logicTableNames)
                 : new ShardingInstanceBroadcastRouteEngine(database.getResourceMetaData());
     }
     
     private static boolean isDCLForSingleTable(final SQLStatementContext sqlStatementContext) {
         return 1 == sqlStatementContext.getTablesContext().getSimpleTables().size()
                 && !"*".equals(sqlStatementContext.getTablesContext().getSimpleTables().iterator().next().getTableName().getIdentifier().getValue());
     }
     
     private static ShardingRouteEngine getDQLRouteEngine(final ShardingRule rule, final SQLStatementContext sqlStatementContext,
                                                          final QueryContext queryContext, final ShardingConditions shardingConditions, final Collection<String> logicTableNames,
                                                          final ConfigurationProperties props) {
         Collection<String> tableNames = sqlStatementContext.getTablesContext().getTableNames();
         if (sqlStatementContext.getSqlStatement() instanceof DMLStatement && shardingConditions.isAlwaysFalse() || tableNames.isEmpty()) {
             return new ShardingUnicastRouteEngine(sqlStatementContext, tableNames, queryContext.getConnectionContext());
         }
         return getDQLRouteEngineForShardingTable(rule, sqlStatementContext, queryContext.getHintValueContext(), shardingConditions, logicTableNames, props);
     }
     
     private static ShardingRouteEngine getDQLRouteEngineForShardingTable(final ShardingRule rule, final SQLStatementContext sqlStatementContext, final HintValueContext hintValueContext,
                                                                          final ShardingConditions shardingConditions, final Collection<String> logicTableNames, final ConfigurationProperties props) {
         boolean allBindingTables = logicTableNames.size() > 1 && rule.isBindingTablesUseShardingColumnsJoin(sqlStatementContext, logicTableNames);
         if (isShardingStandardQuery(rule, logicTableNames, allBindingTables)) {
             return new ShardingStandardRouteEngine(getLogicTableName(shardingConditions, logicTableNames), shardingConditions, sqlStatementContext, hintValueContext, props);
         }
         // TODO config for cartesian set
         return new ShardingComplexRouteEngine(shardingConditions, sqlStatementContext, hintValueContext, props, logicTableNames);
     }
     
     private static String getLogicTableName(final ShardingConditions shardingConditions, final Collection<String> tableNames) {
         if (shardingConditions.getConditions().isEmpty()) {
             return tableNames.iterator().next();
         }
         ShardingCondition shardingCondition = shardingConditions.getConditions().iterator().next();
         return shardingCondition.getValues().isEmpty() ? tableNames.iterator().next() : shardingCondition.getValues().iterator().next().getTableName();
     }
     
     private static boolean isShardingStandardQuery(final ShardingRule rule, final Collection<String> logicTableNames, final boolean allBindingTables) {
         return 1 == logicTableNames.size() && rule.isAllShardingTables(logicTableNames) || allBindingTables;
     }
 }