/*
 * 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.arrow.vector;

import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED;

import org.apache.arrow.memory.ArrowBuf;
import org.apache.arrow.memory.BufferAllocator;
import org.apache.arrow.vector.types.pojo.Field;
import org.apache.arrow.vector.types.pojo.FieldType;
import org.apache.arrow.vector.util.TransferPair;

/**
 * TimeStampVector is an abstract interface for fixed width vector (8 bytes)
 * of timestamp values which could be null. A validity buffer (bit vector) is
 * maintained to track which elements in the vector are null.
 */
public abstract class TimeStampVector extends BaseFixedWidthVector {
  public static final byte TYPE_WIDTH = 8;

  /**
   * Instantiate a TimeStampVector. This doesn't allocate any memory for
   * the data in vector.
   *
   * @param name name of the vector
   * @param fieldType type of Field materialized by this vector
   * @param allocator allocator for memory management.
   */
  public TimeStampVector(String name, FieldType fieldType, BufferAllocator allocator) {
    this(new Field(name, fieldType, null), allocator);
  }

  /**
   * Instantiate a TimeStampVector. This doesn't allocate any memory for
   * the data in vector.
   *
   * @param field field materialized by this vector
   * @param allocator allocator for memory management.
   */
  public TimeStampVector(Field field, BufferAllocator allocator) {
    super(field, allocator, TYPE_WIDTH);
  }


  /*----------------------------------------------------------------*
   |                                                                |
   |          vector value retrieval methods                        |
   |                                                                |
   *----------------------------------------------------------------*/

  /**
   * Get the element at the given index from the vector.
   *
   * @param index   position of element
   * @return element at given index
   */
  public long get(int index) throws IllegalStateException {
    if (NULL_CHECKING_ENABLED && isSet(index) == 0) {
      throw new IllegalStateException("Value at index is null");
    }
    return valueBuffer.getLong((long) index * TYPE_WIDTH);
  }


  /*----------------------------------------------------------------*
   |                                                                |
   |          vector value setter methods                           |
   |                                                                |
   *----------------------------------------------------------------*/


  protected void setValue(int index, long value) {
    valueBuffer.setLong((long) index * TYPE_WIDTH, value);
  }

  /**
   * Set the element at the given index to the given value.
   *
   * @param index   position of element
   * @param value   value of element
   */
  public void set(int index, long value) {
    BitVectorHelper.setBit(validityBuffer, index);
    setValue(index, value);
  }

  /**
   * Same as {@link #set(int, long)} except that it handles the
   * case when index is greater than or equal to existing
   * value capacity {@link #getValueCapacity()}.
   *
   * @param index   position of element
   * @param value   value of element
   */
  public void setSafe(int index, long value) {
    handleSafe(index);
    set(index, value);
  }

  /**
   * Store the given value at a particular position in the vector. isSet indicates
   * whether the value is NULL or not.
   *
   * @param index position of the new value
   * @param isSet 0 for NULL value, 1 otherwise
   * @param value element value
   */
  public void set(int index, int isSet, long value) {
    if (isSet > 0) {
      set(index, value);
    } else {
      BitVectorHelper.unsetBit(validityBuffer, index);
    }
  }

  /**
   * Same as {@link #set(int, int, long)} except that it handles the case
   * when index is greater than or equal to current value capacity of the
   * vector.
   *
   * @param index position of the new value
   * @param isSet 0 for NULL value, 1 otherwise
   * @param value element value
   */
  public void setSafe(int index, int isSet, long value) {
    handleSafe(index);
    set(index, isSet, value);
  }

  /**
   * Given a data buffer, get the value stored at a particular position
   * in the vector.
   *
   * <p>This method should not be used externally.
   *
   * @param buffer data buffer
   * @param index position of the element.
   * @return value stored at the index.
   */
  public static long get(final ArrowBuf buffer, final int index) {
    return buffer.getLong((long) index * TYPE_WIDTH);
  }


  /*----------------------------------------------------------------*
   |                                                                |
   |                      vector transfer                           |
   |                                                                |
   *----------------------------------------------------------------*/


  /**
   * {@link TransferPair} for {@link TimeStampVector}.
   */
  public class TransferImpl implements TransferPair {
    TimeStampVector to;

    public TransferImpl(TimeStampVector to) {
      this.to = to;
    }

    @Override
    public TimeStampVector getTo() {
      return to;
    }

    @Override
    public void transfer() {
      transferTo(to);
    }

    @Override
    public void splitAndTransfer(int startIndex, int length) {
      splitAndTransferTo(startIndex, length, to);
    }

    @Override
    public void copyValueSafe(int fromIndex, int toIndex) {
      to.copyFromSafe(fromIndex, toIndex, TimeStampVector.this);
    }
  }
}
