/*
    * 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.ddl;
  
  import lombok.Getter;
  import org.apache.shardingsphere.infra.binder.context.aware.CursorDefinitionAware;
  import org.apache.shardingsphere.infra.binder.context.segment.table.TablesContext;
  import org.apache.shardingsphere.infra.binder.context.statement.CommonSQLStatementContext;
  import org.apache.shardingsphere.infra.binder.context.type.CursorAvailable;
  import org.apache.shardingsphere.infra.binder.context.type.WhereAvailable;
  import org.apache.shardingsphere.sql.parser.sql.common.extractor.TableExtractor;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.ddl.cursor.CursorNameSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.column.ColumnSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.expr.BinaryOperationExpression;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.predicate.WhereSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.statement.ddl.FetchStatement;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Optional;
  
  /**
   * Fetch statement context.
   */
  @Getter
  public final class FetchStatementContext extends CommonSQLStatementContext implements CursorAvailable, WhereAvailable, CursorDefinitionAware {
      
      private CursorStatementContext cursorStatementContext;
      
      private TablesContext tablesContext;
      
      public FetchStatementContext(final FetchStatement sqlStatement) {
          super(sqlStatement);
          tablesContext = new TablesContext(Collections.emptyList(), getDatabaseType());
      }
      
      @Override
      public FetchStatement getSqlStatement() {
          return (FetchStatement) super.getSqlStatement();
      }
      
      @Override
      public Optional<CursorNameSegment> getCursorName() {
          return Optional.of(getSqlStatement().getCursorName());
      }
      
      @Override
      public void setUpCursorDefinition(final CursorStatementContext cursorStatementContext) {
          this.cursorStatementContext = cursorStatementContext;
          TableExtractor tableExtractor = new TableExtractor();
          tableExtractor.extractTablesFromSelect(cursorStatementContext.getSqlStatement().getSelect());
          tablesContext = new TablesContext(tableExtractor.getRewriteTables(), getDatabaseType());
      }
      
      @Override
      public Collection<WhereSegment> getWhereSegments() {
          return null == cursorStatementContext ? Collections.emptyList() : cursorStatementContext.getWhereSegments();
      }
      
      @Override
      public Collection<ColumnSegment> getColumnSegments() {
          return null == cursorStatementContext ? Collections.emptyList() : cursorStatementContext.getColumnSegments();
      }
      
      @Override
      public Collection<BinaryOperationExpression> getJoinConditions() {
          return null == cursorStatementContext ? Collections.emptyList() : cursorStatementContext.getJoinConditions();
      }
  }