/**
 * 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.drill.exec.store;

import com.google.common.collect.Lists;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rel.type.RelDataTypeFactory;
import org.apache.calcite.sql.type.SqlTypeName;

import java.util.List;

/**
 * RecordDataType defines names and data types of columns in a static drill table.
 */
public abstract class RecordDataType {

  /**
   * @return the {@link org.apache.calcite.sql.type.SqlTypeName} of columns in the table
   */
  public abstract List<SqlTypeName> getFieldSqlTypeNames();

  /**
   * @return the column names in the table
   */
  public abstract List<String> getFieldNames();

  /**
   * This method constructs a {@link org.apache.calcite.rel.type.RelDataType} based on the
   * {@link org.apache.drill.exec.store.RecordDataType}'s field sql types and field names.
   *
   * @param factory helps construct a {@link org.apache.calcite.rel.type.RelDataType}
   * @return the constructed type
   */
  public final RelDataType getRowType(RelDataTypeFactory factory) {
    final List<SqlTypeName> types = getFieldSqlTypeNames();
    final List<String> names = getFieldNames();
    final List<RelDataType> fields = Lists.newArrayList();
    for (final SqlTypeName typeName : types) {
      switch (typeName) {
        case VARCHAR:
          fields.add(factory.createSqlType(typeName, Integer.MAX_VALUE));
          break;
        default:
          fields.add(factory.createSqlType(typeName));
      }
    }
    return factory.createStructType(fields, names);
  }

}