/*
 * 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.accumulo.tserver.scan;

import java.util.concurrent.atomic.AtomicBoolean;

import org.apache.accumulo.core.client.SampleNotPresentException;
import org.apache.accumulo.core.iterators.IterationInterruptedException;
import org.apache.accumulo.server.util.Halt;
import org.apache.accumulo.tserver.TabletServer;
import org.apache.accumulo.tserver.TooManyFilesException;
import org.apache.accumulo.tserver.session.ScanSession;
import org.apache.accumulo.tserver.tablet.ScanBatch;
import org.apache.accumulo.tserver.tablet.Tablet;
import org.apache.accumulo.tserver.tablet.TabletClosedException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class NextBatchTask extends ScanTask<ScanBatch> {

  private static final Logger log = LoggerFactory.getLogger(NextBatchTask.class);

  private final long scanID;

  public NextBatchTask(TabletServer server, long scanID, AtomicBoolean interruptFlag) {
    super(server);
    this.scanID = scanID;
    this.interruptFlag = interruptFlag;

    if (interruptFlag.get())
      cancel(true);
  }

  @Override
  public void run() {

    final ScanSession scanSession = (ScanSession) server.getSession(scanID);
    String oldThreadName = Thread.currentThread().getName();

    try {
      if (isCancelled() || scanSession == null)
        return;

      runState.set(ScanRunState.RUNNING);

      Thread.currentThread().setName(
          "User: " + scanSession.getUser() + " Start: " + scanSession.startTime + " Client: " + scanSession.client + " Tablet: " + scanSession.extent);

      Tablet tablet = server.getOnlineTablet(scanSession.extent);

      if (tablet == null) {
        addResult(new org.apache.accumulo.core.tabletserver.thrift.NotServingTabletException(scanSession.extent.toThrift()));
        return;
      }

      long t1 = System.currentTimeMillis();
      ScanBatch batch = scanSession.scanner.read();
      long t2 = System.currentTimeMillis();
      scanSession.nbTimes.addStat(t2 - t1);

      // there should only be one thing on the queue at a time, so
      // it should be ok to call add()
      // instead of put()... if add() fails because queue is at
      // capacity it means there is code
      // problem somewhere
      addResult(batch);
    } catch (TabletClosedException e) {
      addResult(new org.apache.accumulo.core.tabletserver.thrift.NotServingTabletException(scanSession.extent.toThrift()));
    } catch (IterationInterruptedException iie) {
      if (!isCancelled()) {
        log.warn("Iteration interrupted, when scan not cancelled", iie);
        addResult(iie);
      }
    } catch (TooManyFilesException | SampleNotPresentException e) {
      addResult(e);
    } catch (OutOfMemoryError ome) {
      Halt.halt("Ran out of memory scanning " + scanSession.extent + " for " + scanSession.client, 1);
      addResult(ome);
    } catch (Throwable e) {
      log.warn("exception while scanning tablet " + (scanSession == null ? "(unknown)" : scanSession.extent), e);
      addResult(e);
    } finally {
      runState.set(ScanRunState.FINISHED);
      Thread.currentThread().setName(oldThreadName);
    }

  }
}