package com.yahoo.labs.samoa;

/*
 * #%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.nio.file.FileSystems;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

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

import com.github.javacliparser.ClassOption;
import com.yahoo.labs.samoa.tasks.Task;
import com.yahoo.labs.samoa.topology.impl.SamzaComponentFactory;
import com.yahoo.labs.samoa.topology.impl.SamzaEngine;
import com.yahoo.labs.samoa.topology.impl.SamzaTopology;
import com.yahoo.labs.samoa.utils.SystemsUtils;

/**
 * Main class to run the task on Samza
 * 
 * @author Anh Thu Vu
 */
public class SamzaDoTask {

  private static final Logger logger = LoggerFactory.getLogger(SamzaDoTask.class);

  private static final String LOCAL_MODE = "local";
  private static final String YARN_MODE = "yarn";

  // FLAGS
  private static final String YARN_CONF_FLAG = "--yarn_home";
  private static final String MODE_FLAG = "--mode";
  private static final String ZK_FLAG = "--zookeeper";
  private static final String KAFKA_FLAG = "--kafka";
  private static final String KAFKA_REPLICATION_FLAG = "--kafka_replication_factor";
  private static final String CHECKPOINT_FREQ_FLAG = "--checkpoint_frequency";
  private static final String JAR_PACKAGE_FLAG = "--jar_package";
  private static final String SAMOA_HDFS_DIR_FLAG = "--samoa_hdfs_dir";
  private static final String AM_MEMORY_FLAG = "--yarn_am_mem";
  private static final String CONTAINER_MEMORY_FLAG = "--yarn_container_mem";
  private static final String PI_PER_CONTAINER_FLAG = "--pi_per_container";

  private static final String KRYO_REGISTER_FLAG = "--kryo_register";

  // config values
  private static int kafkaReplicationFactor = 1;
  private static int checkpointFrequency = 60000;
  private static String kafka = "localhost:9092";
  private static String zookeeper = "localhost:2181";
  private static boolean isLocal = true;
  private static String yarnConfHome = null;
  private static String samoaHDFSDir = null;
  private static String jarPackagePath = null;
  private static int amMem = 1024;
  private static int containerMem = 1024;
  private static int piPerContainer = 2;
  private static String kryoRegisterFile = null;

  /*
   * 1. Read arguments 2. Construct topology/task 3. Upload the JAR to HDFS if
   * we are running on YARN 4. Submit topology to SamzaEngine
   */
  public static void main(String[] args) {
    // Read arguments
    List<String> tmpArgs = new ArrayList<String>(Arrays.asList(args));
    parseArguments(tmpArgs);

    args = tmpArgs.toArray(new String[0]);

    // Init Task
    StringBuilder cliString = new StringBuilder();
    for (int i = 0; i < args.length; i++) {
      cliString.append(" ").append(args[i]);
    }
    logger.debug("Command line string = {}", cliString.toString());
    System.out.println("Command line string = " + cliString.toString());

    Task task = null;
    try {
      task = (Task) ClassOption.cliStringToObject(cliString.toString(), Task.class, null);
      logger.info("Sucessfully instantiating {}", task.getClass().getCanonicalName());
    } catch (Exception e) {
      logger.error("Fail to initialize the task", e);
      System.out.println("Fail to initialize the task" + e);
      return;
    }
    task.setFactory(new SamzaComponentFactory());
    task.init();

    // Upload JAR file to HDFS
    String hdfsPath = null;
    if (!isLocal) {
      Path path = FileSystems.getDefault().getPath(jarPackagePath);
      hdfsPath = uploadJarToHDFS(path.toFile());
      if (hdfsPath == null) {
        System.out.println("Fail uploading JAR file \"" + path.toAbsolutePath().toString() + "\" to HDFS.");
        return;
      }
    }

    // Set parameters
    SamzaEngine.getEngine()
        .setLocalMode(isLocal)
        .setZooKeeper(zookeeper)
        .setKafka(kafka)
        .setYarnPackage(hdfsPath)
        .setKafkaReplicationFactor(kafkaReplicationFactor)
        .setConfigHome(yarnConfHome)
        .setAMMemory(amMem)
        .setContainerMemory(containerMem)
        .setPiPerContainerRatio(piPerContainer)
        .setKryoRegisterFile(kryoRegisterFile)
        .setCheckpointFrequency(checkpointFrequency);

    // Submit topology
    SamzaEngine.submitTopology((SamzaTopology) task.getTopology());

  }

  private static boolean isLocalMode(String mode) {
    return mode.equals(LOCAL_MODE);
  }

  private static void parseArguments(List<String> args) {
    for (int i = args.size() - 1; i >= 0; i--) {
      String arg = args.get(i).trim();
      String[] splitted = arg.split("=", 2);

      if (splitted.length >= 2) {
        // YARN config folder which contains conf/core-site.xml,
        // conf/hdfs-site.xml, conf/yarn-site.xml
        if (splitted[0].equals(YARN_CONF_FLAG)) {
          yarnConfHome = splitted[1];
          args.remove(i);
        }
        // host:port for zookeeper cluster
        else if (splitted[0].equals(ZK_FLAG)) {
          zookeeper = splitted[1];
          args.remove(i);
        }
        // host:port,... for kafka broker(s)
        else if (splitted[0].equals(KAFKA_FLAG)) {
          kafka = splitted[1];
          args.remove(i);
        }
        // whether we are running Samza in Local mode or YARN mode
        else if (splitted[0].equals(MODE_FLAG)) {
          isLocal = isLocalMode(splitted[1]);
          args.remove(i);
        }
        // memory requirement for YARN application master
        else if (splitted[0].equals(AM_MEMORY_FLAG)) {
          amMem = Integer.parseInt(splitted[1]);
          args.remove(i);
        }
        // memory requirement for YARN worker container
        else if (splitted[0].equals(CONTAINER_MEMORY_FLAG)) {
          containerMem = Integer.parseInt(splitted[1]);
          args.remove(i);
        }
        // the path to JAR archive that we need to upload to HDFS
        else if (splitted[0].equals(JAR_PACKAGE_FLAG)) {
          jarPackagePath = splitted[1];
          args.remove(i);
        }
        // the HDFS dir for SAMOA files
        else if (splitted[0].equals(SAMOA_HDFS_DIR_FLAG)) {
          samoaHDFSDir = splitted[1];
          if (samoaHDFSDir.length() < 1)
            samoaHDFSDir = null;
          args.remove(i);
        }
        // number of max PI instances per container
        // this will be used to compute the number of containers
        // AM will request for the job
        else if (splitted[0].equals(PI_PER_CONTAINER_FLAG)) {
          piPerContainer = Integer.parseInt(splitted[1]);
          args.remove(i);
        }
        // kafka streams replication factor
        else if (splitted[0].equals(KAFKA_REPLICATION_FLAG)) {
          kafkaReplicationFactor = Integer.parseInt(splitted[1]);
          args.remove(i);
        }
        // checkpoint frequency in ms
        else if (splitted[0].equals(CHECKPOINT_FREQ_FLAG)) {
          checkpointFrequency = Integer.parseInt(splitted[1]);
          args.remove(i);
        }
        // the file contains registration information for Kryo serializer
        else if (splitted[0].equals(KRYO_REGISTER_FLAG)) {
          kryoRegisterFile = splitted[1];
          args.remove(i);
        }
      }
    }
  }

  private static String uploadJarToHDFS(File file) {
    SystemsUtils.setHadoopConfigHome(yarnConfHome);
    SystemsUtils.setSAMOADir(samoaHDFSDir);
    return SystemsUtils.copyToHDFS(file, file.getName());
  }
}