/*
 * 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.lucene.sandbox.search;

import java.io.IOException;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.Collector;
import org.apache.lucene.search.FilterCollector;
import org.apache.lucene.search.FilterLeafCollector;
import org.apache.lucene.search.LeafCollector;
import org.apache.lucene.search.Scorable;
import org.apache.lucene.search.ScoreMode;

/** A collector that profiles how much time is spent calling it. */
class ProfilerCollectorWrapper extends FilterCollector {

  private long time;

  /** Sole constructor. */
  ProfilerCollectorWrapper(Collector in) {
    super(in);
  }

  @Override
  public ScoreMode scoreMode() {
    final long start = System.nanoTime();
    try {
      return super.scoreMode();
    } finally {
      time += Math.max(1, System.nanoTime() - start);
    }
  }

  @Override
  public LeafCollector getLeafCollector(LeafReaderContext context) throws IOException {
    final long start = System.nanoTime();
    final LeafCollector inLeafCollector;
    try {
      inLeafCollector = super.getLeafCollector(context);
    } finally {
      time += Math.max(1, System.nanoTime() - start);
    }
    return new FilterLeafCollector(inLeafCollector) {

      @Override
      public void collect(int doc) throws IOException {
        final long start = System.nanoTime();
        try {
          super.collect(doc);
        } finally {
          time += Math.max(1, System.nanoTime() - start);
        }
      }

      @Override
      public void setScorer(Scorable scorer) throws IOException {
        final long start = System.nanoTime();
        try {
          super.setScorer(scorer);
        } finally {
          time += Math.max(1, System.nanoTime() - start);
        }
      }
    };
  }

  /** Return the total time spent on this collector. */
  public long getTime() {
    return time;
  }
}
