package com.yahoo.labs.samoa.utils;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2015 Apache Software Foundation
 * %%
 * Licensed 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.
 * #L%
 */

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.nio.file.FileSystems;
import java.util.Map;
import java.util.Properties;

import kafka.admin.AdminUtils;
import kafka.utils.ZKStringSerializer;

import org.I0Itec.zkclient.ZkClient;
import org.I0Itec.zkclient.exception.ZkMarshallingError;
import org.I0Itec.zkclient.serialize.ZkSerializer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Utilities methods for: - Kafka - HDFS - Handling files on local FS
 * 
 * @author Anh Thu Vu
 */
public class SystemsUtils {
  private static final Logger logger = LoggerFactory.getLogger(SystemsUtils.class);

  public static final String HDFS = "hdfs";
  public static final String LOCAL_FS = "local";

  private static final String TEMP_FILE = "samoaTemp";
  private static final String TEMP_FILE_SUFFIX = ".dat";

  /*
   * Kafka
   */
  private static class KafkaUtils {
    private static ZkClient zkClient;

    static void setZookeeper(String zk) {
      zkClient = new ZkClient(zk, 30000, 30000, new ZKStringSerializerWrapper());
    }

    /*
     * Create Kafka topic/stream
     */
    static void createKafkaTopic(String name, int partitions, int replicas) {
      AdminUtils.createTopic(zkClient, name, partitions, replicas, new Properties());
    }

    static class ZKStringSerializerWrapper implements ZkSerializer {
      @Override
      public Object deserialize(byte[] byteArray) throws ZkMarshallingError {
        return ZKStringSerializer.deserialize(byteArray);
      }

      @Override
      public byte[] serialize(Object obj) throws ZkMarshallingError {
        return ZKStringSerializer.serialize(obj);
      }
    }
  }

  /*
   * HDFS
   */
  private static class HDFSUtils {
    private static String coreConfPath;
    private static String hdfsConfPath;
    private static String configHomePath;
    private static String samoaDir = null;

    static void setHadoopConfigHome(String hadoopConfPath) {
      logger.info("Hadoop config home:{}", hadoopConfPath);
      configHomePath = hadoopConfPath;
      java.nio.file.Path coreSitePath = FileSystems.getDefault().getPath(hadoopConfPath, "core-site.xml");
      java.nio.file.Path hdfsSitePath = FileSystems.getDefault().getPath(hadoopConfPath, "hdfs-site.xml");
      coreConfPath = coreSitePath.toAbsolutePath().toString();
      hdfsConfPath = hdfsSitePath.toAbsolutePath().toString();
    }

    static String getNameNodeUri() {
      Configuration config = new Configuration();
      config.addResource(new Path(coreConfPath));
      config.addResource(new Path(hdfsConfPath));

      return config.get("fs.defaultFS");
    }

    static String getHadoopConfigHome() {
      return configHomePath;
    }

    static void setSAMOADir(String dir) {
      if (dir != null)
        samoaDir = getNameNodeUri() + dir;
      else
        samoaDir = null;
    }

    static String getDefaultSAMOADir() throws IOException {
      Configuration config = new Configuration();
      config.addResource(new Path(coreConfPath));
      config.addResource(new Path(hdfsConfPath));

      FileSystem fs = FileSystem.get(config);
      Path defaultDir = new Path(fs.getHomeDirectory(), ".samoa");
      return defaultDir.toString();
    }

    static boolean deleteFileIfExist(String absPath) {
      Path p = new Path(absPath);
      return deleteFileIfExist(p);
    }

    static boolean deleteFileIfExist(Path p) {
      Configuration config = new Configuration();
      config.addResource(new Path(coreConfPath));
      config.addResource(new Path(hdfsConfPath));

      FileSystem fs;
      try {
        fs = FileSystem.get(config);
        if (fs.exists(p)) {
          return fs.delete(p, false);
        }
        else
          return true;
      } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
      return false;
    }

    /*
     * Write to HDFS
     */
    static String writeToHDFS(File file, String dstPath) {
      Configuration config = new Configuration();
      config.addResource(new Path(coreConfPath));
      config.addResource(new Path(hdfsConfPath));
      logger.info("Filesystem name:{}", config.get("fs.defaultFS"));

      // Default samoaDir
      if (samoaDir == null) {
        try {
          samoaDir = getDefaultSAMOADir();
        } catch (IOException e) {
          e.printStackTrace();
          return null;
        }
      }

      // Setup src and dst paths
      // java.nio.file.Path tempPath =
      // FileSystems.getDefault().getPath(samoaDir, dstPath);
      Path dst = new Path(samoaDir, dstPath);
      Path src = new Path(file.getAbsolutePath());

      // Delete file if already exists in HDFS
      if (deleteFileIfExist(dst) == false)
        return null;

      // Copy to HDFS
      FileSystem fs;
      try {
        fs = FileSystem.get(config);
        fs.copyFromLocalFile(src, dst);
      } catch (IOException e) {
        e.printStackTrace();
        return null;
      }

      return dst.toString(); // abs path to file
    }

    /*
     * Read from HDFS
     */
    static Object deserializeObjectFromFile(String filePath) {
      logger.info("Deserialize HDFS file:{}", filePath);
      Configuration config = new Configuration();
      config.addResource(new Path(coreConfPath));
      config.addResource(new Path(hdfsConfPath));

      Path file = new Path(filePath);
      FSDataInputStream dataInputStream = null;
      ObjectInputStream ois = null;
      Object obj = null;
      FileSystem fs;
      try {
        fs = FileSystem.get(config);
        dataInputStream = fs.open(file);
        ois = new ObjectInputStream(dataInputStream);
        obj = ois.readObject();
      } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      } catch (ClassNotFoundException e) {
        try {
          if (dataInputStream != null)
            dataInputStream.close();
          if (ois != null)
            ois.close();
        } catch (IOException ioException) {
          // TODO auto-generated catch block
          e.printStackTrace();
        }
      }

      return obj;
    }

  }

  private static class LocalFileSystemUtils {
    static boolean serializObjectToFile(Object obj, String fn) {
      FileOutputStream fos = null;
      ObjectOutputStream oos = null;
      try {
        fos = new FileOutputStream(fn);
        oos = new ObjectOutputStream(fos);
        oos.writeObject(obj);
      } catch (FileNotFoundException e) {
        e.printStackTrace();
        return false;
      } catch (IOException e) {
        e.printStackTrace();
        return false;
      } finally {
        try {
          if (fos != null)
            fos.close();
          if (oos != null)
            oos.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }

      return true;
    }

    static Object deserializeObjectFromLocalFile(String filename) {
      logger.info("Deserialize local file:{}", filename);
      FileInputStream fis = null;
      ObjectInputStream ois = null;
      Object obj = null;
      try {
        fis = new FileInputStream(filename);
        ois = new ObjectInputStream(fis);
        obj = ois.readObject();
      } catch (IOException e) {
        // TODO auto-generated catch block
        e.printStackTrace();
      } catch (ClassNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      } finally {
        try {
          if (fis != null)
            fis.close();
          if (ois != null)
            ois.close();
        } catch (IOException e) {
          // TODO auto-generated catch block
          e.printStackTrace();
        }
      }

      return obj;
    }
  }

  /*
   * Create streams
   */
  public static void createKafkaTopic(String name, int partitions) {
    createKafkaTopic(name, partitions, 1);
  }

  public static void createKafkaTopic(String name, int partitions, int replicas) {
    KafkaUtils.createKafkaTopic(name, partitions, replicas);
  }

  /*
   * Serialize object
   */
  public static boolean serializeObjectToLocalFileSystem(Object object, String path) {
    return LocalFileSystemUtils.serializObjectToFile(object, path);
  }

  public static String serializeObjectToHDFS(Object object, String path) {
    File tmpDatFile;
    try {
      tmpDatFile = File.createTempFile(TEMP_FILE, TEMP_FILE_SUFFIX);
      if (serializeObjectToLocalFileSystem(object, tmpDatFile.getAbsolutePath())) {
        return HDFSUtils.writeToHDFS(tmpDatFile, path);
      }
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    return null;
  }

  /*
   * Deserialize object
   */
  @SuppressWarnings("unchecked")
  public static Map<String, Object> deserializeMapFromFile(String filesystem, String filename) {
    Map<String, Object> map;
    if (filesystem.equals(HDFS)) {
      map = (Map<String, Object>) HDFSUtils.deserializeObjectFromFile(filename);
    }
    else {
      map = (Map<String, Object>) LocalFileSystemUtils.deserializeObjectFromLocalFile(filename);
    }
    return map;
  }

  public static Object deserializeObjectFromFileAndKey(String filesystem, String filename, String key) {
    Map<String, Object> map = deserializeMapFromFile(filesystem, filename);
    if (map == null)
      return null;
    return map.get(key);
  }

  /*
   * Setup
   */
  public static void setZookeeper(String zookeeper) {
    KafkaUtils.setZookeeper(zookeeper);
  }

  public static void setHadoopConfigHome(String hadoopHome) {
    HDFSUtils.setHadoopConfigHome(hadoopHome);
  }

  public static void setSAMOADir(String samoaDir) {
    HDFSUtils.setSAMOADir(samoaDir);
  }

  /*
   * Others
   */
  public static String getHDFSNameNodeUri() {
    return HDFSUtils.getNameNodeUri();
  }

  public static String getHadoopConfigHome() {
    return HDFSUtils.getHadoopConfigHome();
  }

  public static String copyToHDFS(File file, String dstPath) {
    return HDFSUtils.writeToHDFS(file, dstPath);
  }
}