/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the "License"). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio.master.file;

import alluxio.exception.FileDoesNotExistException;
import alluxio.heartbeat.HeartbeatExecutor;
import alluxio.master.file.meta.Inode;
import alluxio.master.file.meta.InodeTree;
import alluxio.master.file.meta.LockedInodePath;
import alluxio.master.file.meta.PersistenceState;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.concurrent.NotThreadSafe;

/**
 * Lost files periodic check.
 */
@NotThreadSafe
final class LostFileDetector implements HeartbeatExecutor {
  private static final Logger LOG = LoggerFactory.getLogger(LostFileDetector.class);
  private final FileSystemMaster mFileSystemMaster;
  private final InodeTree mInodeTree;

  /**
   * Constructs a new {@link LostFileDetector}.
   */
  public LostFileDetector(FileSystemMaster fileSystemMaster, InodeTree inodeTree) {
    mFileSystemMaster = fileSystemMaster;
    mInodeTree = inodeTree;
  }

  @Override
  public void heartbeat() {
    for (long fileId : mFileSystemMaster.getLostFiles()) {
      // update the state
      try (LockedInodePath inodePath = mInodeTree
          .lockFullInodePath(fileId, InodeTree.LockMode.WRITE)) {
        Inode<?> inode = inodePath.getInode();
        if (inode.getPersistenceState() != PersistenceState.PERSISTED) {
          inode.setPersistenceState(PersistenceState.LOST);
        }
      } catch (FileDoesNotExistException e) {
        LOG.error("Exception trying to get inode from inode tree", e);
      }
    }
  }

  @Override
  public void close() {
    // Nothing to clean up
  }
}