/*
    * 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.binder.context.statement.dal;
  
  import lombok.Getter;
  import org.apache.shardingsphere.infra.binder.context.statement.CommonSQLStatementContext;
  import org.apache.shardingsphere.infra.binder.context.segment.table.TablesContext;
  import org.apache.shardingsphere.infra.binder.context.type.TableAvailable;
  import org.apache.shardingsphere.sql.parser.sql.common.extractor.TableExtractor;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.generic.table.SimpleTableSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.statement.SQLStatement;
  import org.apache.shardingsphere.sql.parser.sql.common.statement.dal.ExplainStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.handler.dal.ExplainStatementHandler;
  
  import java.util.Collection;
  import java.util.LinkedList;
  
  /**
   * Explain statement context.
   */
  @Getter
  public final class ExplainStatementContext extends CommonSQLStatementContext implements TableAvailable {
      
      private final TablesContext tablesContext;
      
      public ExplainStatementContext(final ExplainStatement sqlStatement) {
          super(sqlStatement);
          tablesContext = new TablesContext(extractTablesFromExplain(sqlStatement), getDatabaseType());
      }
      
      private Collection<SimpleTableSegment> extractTablesFromExplain(final ExplainStatement sqlStatement) {
          Collection<SimpleTableSegment> result = new LinkedList<>();
          ExplainStatementHandler.getSimpleTableSegment(sqlStatement).ifPresent(result::add);
          SQLStatement explainableStatement = sqlStatement.getStatement().orElse(null);
          TableExtractor extractor = new TableExtractor();
          // TODO extract table from declare, execute, createMaterializedView, refreshMaterializedView
          extractor.extractTablesFromSQLStatement(explainableStatement);
          result.addAll(extractor.getRewriteTables());
          return result;
      }
      
      @Override
      public ExplainStatement getSqlStatement() {
          return (ExplainStatement) super.getSqlStatement();
      }
      
      @Override
      public Collection<SimpleTableSegment> getAllTables() {
          return extractTablesFromExplain(getSqlStatement());
      }
  }