/*
 * 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.hadoop.hbase.filter;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Objects;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.exceptions.DeserializationException;
import org.apache.yetus.audience.InterfaceAudience;

import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;
import org.apache.hbase.thirdparty.com.google.protobuf.InvalidProtocolBufferException;

import org.apache.hadoop.hbase.shaded.protobuf.generated.FilterProtos;

/**
 * Simple filter that returns first N columns on row only. This filter was written to test filters
 * in Get and as soon as it gets its quota of columns, {@link #filterAllRemaining()} returns true.
 * This makes this filter unsuitable as a Scan filter.
 */
@InterfaceAudience.Public
public class ColumnCountGetFilter extends FilterBase {
  private int limit = 0;
  private int count = 0;

  public ColumnCountGetFilter(final int n) {
    Preconditions.checkArgument(n >= 0, "limit be positive %s", n);
    this.limit = n;
  }

  public int getLimit() {
    return limit;
  }

  @Override
  public boolean filterRowKey(Cell cell) throws IOException {
    // Impl in FilterBase might do unnecessary copy for Off heap backed Cells.
    if (filterAllRemaining()) return true;
    return false;
  }

  @Override
  public boolean filterAllRemaining() {
    return this.count > this.limit;
  }

  @Override
  public ReturnCode filterCell(final Cell c) {
    this.count++;
    return filterAllRemaining() ? ReturnCode.NEXT_COL : ReturnCode.INCLUDE_AND_NEXT_COL;
  }

  @Override
  public void reset() {
    this.count = 0;
  }

  public static Filter createFilterFromArguments(ArrayList<byte[]> filterArguments) {
    Preconditions.checkArgument(filterArguments.size() == 1, "Expected 1 but got: %s",
      filterArguments.size());
    int limit = ParseFilter.convertByteArrayToInt(filterArguments.get(0));
    return new ColumnCountGetFilter(limit);
  }

  /** Returns The filter serialized using pb */
  @Override
  public byte[] toByteArray() {
    FilterProtos.ColumnCountGetFilter.Builder builder =
      FilterProtos.ColumnCountGetFilter.newBuilder();
    builder.setLimit(this.limit);
    return builder.build().toByteArray();
  }

  /**
   * Parse a serialized representation of {@link ColumnCountGetFilter}
   * @param pbBytes A pb serialized {@link ColumnCountGetFilter} instance
   * @return An instance of {@link ColumnCountGetFilter} made from <code>bytes</code>
   * @throws DeserializationException if an error occurred
   * @see #toByteArray
   */
  public static ColumnCountGetFilter parseFrom(final byte[] pbBytes)
    throws DeserializationException {
    FilterProtos.ColumnCountGetFilter proto;
    try {
      proto = FilterProtos.ColumnCountGetFilter.parseFrom(pbBytes);
    } catch (InvalidProtocolBufferException e) {
      throw new DeserializationException(e);
    }
    return new ColumnCountGetFilter(proto.getLimit());
  }

  /**
   * Returns true if and only if the fields of the filter that are serialized are equal to the
   * corresponding fields in other. Used for testing.
   */
  @Override
  boolean areSerializedFieldsEqual(Filter o) {
    if (o == this) {
      return true;
    }
    if (!(o instanceof ColumnCountGetFilter)) {
      return false;
    }
    ColumnCountGetFilter other = (ColumnCountGetFilter) o;
    return this.getLimit() == other.getLimit();
  }

  @Override
  public String toString() {
    return this.getClass().getSimpleName() + " " + this.limit;
  }

  @Override
  public boolean equals(Object obj) {
    return obj instanceof Filter && areSerializedFieldsEqual((Filter) obj);
  }

  @Override
  public int hashCode() {
    return Objects.hash(this.limit);
  }
}
