content: /*
   * 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.calcite.adapter.innodb;
  
  import org.apache.calcite.avatica.util.ByteString;
  import org.apache.calcite.avatica.util.DateTimeUtils;
  import org.apache.calcite.linq4j.Enumerator;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rel.type.RelDataTypeField;
  import org.apache.calcite.sql.type.SqlTypeName;
  
  import com.alibaba.innodb.java.reader.page.index.GenericRecord;
  import com.alibaba.innodb.java.reader.util.Utils;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.sql.Date;
  import java.sql.Time;
  import java.sql.Timestamp;
  import java.time.LocalDate;
  import java.util.Iterator;
  import java.util.List;
  import java.util.TimeZone;
  
  /**
   * Enumerator that reads from InnoDB data file.
   */
  class InnodbEnumerator implements Enumerator<Object> {
    private final Iterator<GenericRecord> iterator;
    private @Nullable GenericRecord current;
    private final List<RelDataTypeField> fieldTypes;
  
    /**
     * Creates an InnodbEnumerator.
     *
     * @param resultIterator result iterator
     * @param rowType   the type of resulting rows
     */
    InnodbEnumerator(Iterator<GenericRecord> resultIterator, RelDataType rowType) {
      this.iterator = resultIterator;
      this.current = null;
      this.fieldTypes = rowType.getFieldList();
    }
  
    /**
     * Produces the next row from the results.
     *
     * @return a new row from the results
     */
    @Override public Object current() {
      if (fieldTypes.size() == 1) {
        // If we just have one field, produce it directly
        return currentRowField(fieldTypes.get(0));
      } else {
        // Build an array with all fields in this row
        Object[] row = new Object[fieldTypes.size()];
        for (int i = 0; i < fieldTypes.size(); i++) {
          row[i] = currentRowField(fieldTypes.get(i));
        }
        return row;
      }
    }
  
    /**
     * Get a field for the current row from the underlying object.
     */
    private @Nullable Object currentRowField(RelDataTypeField relDataTypeField) {
      if (current == null) {
        throw new IllegalStateException();
      }
      final Object o = current.get(relDataTypeField.getName());
      return convertToEnumeratorObject(o, relDataTypeField.getType());
    }
  
    /**
     * Convert an object into the expected internal representation.
     *
     * @param obj         object to convert, if needed
     * @param relDataType data type
     */
    private static @Nullable Object convertToEnumeratorObject(
        @Nullable Object obj, RelDataType relDataType) {
      if (obj == null) {
        return null;
      }
      SqlTypeName sqlTypeName = relDataType.getSqlTypeName();
      switch (sqlTypeName) {
      case BINARY:
      case VARBINARY:
        return new ByteString((byte[]) obj);
      case TIMESTAMP:
      case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
        Timestamp timestamp =
            Utils.convertDateTime((String) obj, relDataType.getPrecision());
        return shift(timestamp).getTime();
      case TIME:
        Time time =
            Utils.convertTime((String) obj, relDataType.getPrecision());
        return shift(time).getTime();
      case DATE:
        Date date = Date.valueOf(LocalDate.parse((String) obj));
        return DateTimeUtils.dateStringToUnixDate(date.toString());
      default:
        return obj;
      }
    }
  
    @Override public boolean moveNext() {
      if (iterator.hasNext()) {
        current = iterator.next();
        return true;
      } else {
        return false;
      }
    }
  
    @Override public void reset() {
      throw new UnsupportedOperationException();
    }
  
    @Override public void close() {
      // Nothing to do here
    }
  
    private static Timestamp shift(Timestamp v) {
      long time = v.getTime();
      int offset = TimeZone.getDefault().getOffset(time);
      return new Timestamp(time + offset);
    }
  
    private static Time shift(Time v) {
      long time = v.getTime();
      int offset = TimeZone.getDefault().getOffset(time);
      return new Time((time + offset) % DateTimeUtils.MILLIS_PER_DAY);
    }
  }
  