/*
    * 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.sqlfederation.optimizer.metadata.schema;
  
  import lombok.RequiredArgsConstructor;
  import lombok.Setter;
  import org.apache.calcite.DataContext;
  import org.apache.calcite.linq4j.AbstractEnumerable;
  import org.apache.calcite.linq4j.Enumerable;
  import org.apache.calcite.linq4j.Enumerator;
  import org.apache.calcite.linq4j.QueryProvider;
  import org.apache.calcite.linq4j.Queryable;
  import org.apache.calcite.linq4j.tree.Expression;
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelOptTable;
  import org.apache.calcite.plan.RelOptTable.ToRelContext;
  import org.apache.calcite.prepare.Prepare.CatalogReader;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.TableModify;
  import org.apache.calcite.rel.core.TableModify.Operation;
  import org.apache.calcite.rel.logical.LogicalTableModify;
  import org.apache.calcite.rel.logical.LogicalTableScan;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rel.type.RelDataTypeFactory;
  import org.apache.calcite.rex.RexNode;
  import org.apache.calcite.schema.ModifiableTable;
  import org.apache.calcite.schema.SchemaPlus;
  import org.apache.calcite.schema.Schemas;
  import org.apache.calcite.schema.Statistic;
  import org.apache.calcite.schema.TranslatableTable;
  import org.apache.calcite.schema.impl.AbstractTable;
  import org.apache.shardingsphere.infra.database.core.type.DatabaseType;
  import org.apache.shardingsphere.infra.exception.generic.UnsupportedSQLOperationException;
  import org.apache.shardingsphere.infra.metadata.database.schema.model.ShardingSphereTable;
  import org.apache.shardingsphere.sqlfederation.optimizer.metadata.schema.table.EmptyRowEnumerator;
  import org.apache.shardingsphere.sqlfederation.optimizer.metadata.schema.table.ScanExecutor;
  import org.apache.shardingsphere.sqlfederation.optimizer.metadata.schema.table.ScanExecutorContext;
  import org.apache.shardingsphere.sqlfederation.optimizer.metadata.util.SQLFederationDataTypeUtils;
  import org.apache.shardingsphere.sqlfederation.optimizer.statistic.SQLFederationStatistic;
  
  import java.lang.reflect.Type;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.List;
  
  /**
   * SQL federation table.
   */
  @RequiredArgsConstructor
  public final class SQLFederationTable extends AbstractTable implements ModifiableTable, TranslatableTable {
      
      private final ShardingSphereTable table;
      
      private final SQLFederationStatistic statistic;
      
      private final DatabaseType protocolType;
      
      @Setter
      private ScanExecutor scanExecutor;
      
      @Override
      public RelDataType getRowType(final RelDataTypeFactory typeFactory) {
          return SQLFederationDataTypeUtils.createRelDataType(table, protocolType, typeFactory);
      }
      
      @Override
      public Expression getExpression(final SchemaPlus schema, final String tableName, final Class clazz) {
          return Schemas.tableExpression(schema, getElementType(), tableName, clazz);
      }
      
      @Override
      public Type getElementType() {
          return Object[].class;
      }
      
      @Override
      public <T> Queryable<T> asQueryable(final QueryProvider queryProvider, final SchemaPlus schema, final String tableName) {
          throw new UnsupportedSQLOperationException("asQueryable");
      }
      
      @Override
      public RelNode toRel(final ToRelContext context, final RelOptTable relOptTable) {
          return LogicalTableScan.create(context.getCluster(), relOptTable, Collections.emptyList());
      }
     
     /**
      * Execute.
      *
      * @param root data context
      * @param sql sql
      * @param paramIndexes param indexes
      * @return enumerable result
      */
     public Enumerable<Object> execute(final DataContext root, final String sql, final int[] paramIndexes) {
         if (null == scanExecutor) {
             return createEmptyEnumerable();
         }
         return scanExecutor.execute(table, new ScanExecutorContext(root, sql, paramIndexes));
     }
     
     private AbstractEnumerable<Object> createEmptyEnumerable() {
         return new AbstractEnumerable<Object>() {
             
             @Override
             public Enumerator<Object> enumerator() {
                 return new EmptyRowEnumerator();
             }
         };
     }
     
     @Override
     public String toString() {
         return "SQLFederationTable";
     }
     
     @Override
     public Statistic getStatistic() {
         return statistic;
     }
     
     @Override
     public Collection<Object[]> getModifiableCollection() {
         throw new UnsupportedOperationException();
     }
     
     @Override
     public TableModify toModificationRel(final RelOptCluster relOptCluster, final RelOptTable table, final CatalogReader schema,
                                          final RelNode relNode, final Operation operation, final List<String> updateColumnList,
                                          final List<RexNode> sourceExpressionList, final boolean flattened) {
         return LogicalTableModify.create(table, schema, relNode, operation, updateColumnList, sourceExpressionList, flattened);
     }
 }