/**
 * 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.tajo.storage;

import org.apache.tajo.common.TajoDataTypes;
import org.apache.tajo.datum.Datum;
import org.apache.tajo.datum.NullDatum;
import org.apache.tajo.datum.ProtobufDatum;
import org.apache.tajo.util.datetime.TimeMeta;

import java.util.Arrays;

/**
 * A tuple which contains all null datums. It is used for outer joins.
 */
public class NullTuple implements Tuple, Cloneable {

  public static Tuple create(int size) {
    return new NullTuple(size);
  }

  private static final byte[] NULL_TEXT_BYTES = new byte[0];

  private final int size;

  NullTuple(int size) {
    this.size = size;
  }

  @Override
  public int size() {
    return size;
  }

  public boolean contains(int fieldId) {
    return fieldId < size;
  }

  @Override
  public boolean isBlank(int fieldid) {
    return false;
  }

  @Override
  public boolean isBlankOrNull(int fieldid) {
    return true;
  }

  @Override
  public void clear() {
  }

  @Override
  public void put(int fieldId, Datum value) {
    throw new UnsupportedOperationException();
  }

  @Override
  public Datum asDatum(int fieldId) {
    return NullDatum.get();
  }

  @Override
  public TajoDataTypes.Type type(int fieldId) {
    return null;
  }

  @Override
  public int size(int fieldId) {
    return 0;
  }

  @Override
  public void clearOffset() {
  }

  @Override
  public void insertTuple(int fieldId, Tuple tuple) {
    throw new UnsupportedOperationException();
  }

  @Override
  public void put(Datum[] values) {
    throw new UnsupportedOperationException();
  }

  @Override
  public void setOffset(long offset) {
  }

  @Override
  public long getOffset() {
    return 0;
  }

  @Override
  public boolean getBool(int fieldId) {
    return NullDatum.get().asBool();
  }

  @Override
  public byte getByte(int fieldId) {
    return NullDatum.get().asByte();
  }

  @Override
  public char getChar(int fieldId) {
    return NullDatum.get().asChar();
  }

  @Override
  public byte[] getBytes(int fieldId) {
    return NullDatum.get().asByteArray();
  }

  @Override
  public byte[] getTextBytes(int fieldId) {
    return NULL_TEXT_BYTES;
  }

  @Override
  public short getInt2(int fieldId) {
    return NullDatum.get().asInt2();
  }

  @Override
  public int getInt4(int fieldId) {
    return NullDatum.get().asInt4();
  }

  @Override
  public long getInt8(int fieldId) {
    return NullDatum.get().asInt8();
  }

  @Override
  public float getFloat4(int fieldId) {
    return NullDatum.get().asFloat4();
  }

  @Override
  public double getFloat8(int fieldId) {
    return NullDatum.get().asFloat8();
  }

  @Override
  public String getText(int fieldId) {
    return NullDatum.get().asChars();
  }

  @Override
  public TimeMeta getTimeDate(int fieldId) {
    return null;
  }

  @Override
  public ProtobufDatum getProtobufDatum(int fieldId) {
    throw new UnsupportedOperationException();
  }

  @Override
  public Datum getInterval(int fieldId) {
    return NullDatum.get();
  }

  @Override
  public char[] getUnicodeChars(int fieldId) {
    return NullDatum.get().asUnicodeChars();
  }

  @Override
  public Tuple clone() throws CloneNotSupportedException {
    return this;
  }

  @Override
  public Datum[] getValues() {
    Datum[] datum = new Datum[size];
    Arrays.fill(datum, NullDatum.get());
    return datum;
  }
}