/*
 * 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.reef.runtime.local.driver;

import org.apache.reef.annotations.audience.Private;
import org.apache.reef.annotations.audience.TaskSide;
import org.apache.reef.runtime.common.files.REEFFileNames;
import org.apache.reef.runtime.local.process.ReefRunnableProcessObserver;
import org.apache.reef.runtime.local.process.RunnableProcess;
import org.apache.reef.runtime.local.process.RunnableProcessObserver;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Arrays;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * A Container that runs an Evaluator in a Process.
 */
@Private
@TaskSide
public final class ProcessContainer implements Container {

  private static final Logger LOG = Logger.getLogger(ProcessContainer.class.getName());

  private final String errorHandlerRID;
  private final String nodeID;
  private final File folder;
  private final String containedID;
  private final int megaBytes;
  private final int numberOfCores;
  private final String rackName;
  private final REEFFileNames fileNames;
  private final File localFolder;
  private final File globalFolder;
  private final RunnableProcessObserver processObserver;
  private final ThreadGroup threadGroup;

  private Thread theThread;
  private RunnableProcess process;

  /**
   * @param errorHandlerRID the remoteID of the error handler.
   * @param nodeID          the ID of the (fake) node this Container is instantiated on
   * @param containedID     the  ID used to identify this container uniquely
   * @param folder          the folder in which logs etc. will be deposited
   */
  ProcessContainer(final String errorHandlerRID,
                   final String nodeID,
                   final String containedID,
                   final File folder,
                   final int megaBytes,
                   final int numberOfCores,
                   final String rackName,
                   final REEFFileNames fileNames,
                   final ReefRunnableProcessObserver processObserver,
                   final ThreadGroup threadGroup) {

    this.errorHandlerRID = errorHandlerRID;
    this.nodeID = nodeID;
    this.containedID = containedID;
    this.folder = folder;
    this.megaBytes = megaBytes;
    this.numberOfCores = numberOfCores;
    this.rackName = rackName;
    this.fileNames = fileNames;
    this.processObserver = processObserver;
    this.threadGroup = threadGroup;

    final File reefFolder = new File(folder, fileNames.getREEFFolderName());

    this.localFolder = new File(reefFolder, fileNames.getLocalFolderName());
    if (!this.localFolder.exists() && !this.localFolder.mkdirs()) {
      LOG.log(Level.WARNING, "Failed to create [{0}]", this.localFolder.getAbsolutePath());
    }

    this.globalFolder = new File(reefFolder, fileNames.getGlobalFolderName());
    if (!this.globalFolder.exists() && !this.globalFolder.mkdirs()) {
      LOG.log(Level.WARNING, "Failed to create [{0}]", this.globalFolder.getAbsolutePath());
    }
  }

  private static void copy(final Iterable<File> files, final File folder) throws IOException {
    for (final File sourceFile : files) {
      final File destinationFile = new File(folder, sourceFile.getName());
      if (Files.isSymbolicLink(sourceFile.toPath())) {
        final Path linkTargetPath = Files.readSymbolicLink(sourceFile.toPath());
        Files.createSymbolicLink(destinationFile.toPath(), linkTargetPath);
      } else {
        Files.copy(sourceFile.toPath(), destinationFile.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING);
      }
    }
  }

  @Override
  public void addLocalFiles(final Iterable<File> files) {
    try {
      copy(files, this.localFolder);
    } catch (final IOException e) {
      throw new RuntimeException("Unable to copy files to the evaluator folder.", e);
    }
  }

  @Override
  public void addGlobalFiles(final File globalFilesFolder) {
    try {
      final File[] files = globalFilesFolder.listFiles();
      if (files != null) {
        copy(Arrays.asList(files), this.globalFolder);
      }
    } catch (final IOException e) {
      throw new RuntimeException("Unable to copy files to the evaluator folder.", e);
    }
  }

  @Override
  public void run(final List<String> commandLine) {

    this.process = new RunnableProcess(
        commandLine,
        this.containedID,
        this.folder,
        this.processObserver,
        this.fileNames.getEvaluatorStdoutFileName(),
        this.fileNames.getEvaluatorStderrFileName());

    this.theThread = new Thread(this.threadGroup, this.process, "ProcessContainer:" + this.containedID);
    this.theThread.start();
  }

  @Override
  public boolean isRunning() {
    return null != this.theThread && this.theThread.isAlive();
  }

  @Override
  public int getMemory() {
    return this.megaBytes;
  }

  @Override
  public int getNumberOfCores() {
    return this.numberOfCores;
  }

  @Override
  public String getRackName() {
    return this.rackName;
  }

  @Override
  public File getFolder() {
    return this.folder;
  }

  @Override
  public String getNodeID() {
    return this.nodeID;
  }

  @Override
  public String getContainerID() {
    return this.containedID;
  }

  @Override
  public void close() {
    if (isRunning()) {
      LOG.log(Level.WARNING, "Force-closing a container that is still running: {0}", this);
      this.process.cancel();
    }
  }

  @Override
  public String toString() {
    return String.format(
        "ProcessContainer{containedID=%s, nodeID=%s, errorHandlerRID=%s, folder=%s, rack=%s}",
        this.containedID, this.nodeID, this.errorHandlerRID, this.folder, this.rackName);
  }
}