/*
 * 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.griffin.measure.sink

import java.util.Date

import org.apache.spark.rdd.RDD

import org.apache.griffin.measure.utils.HdfsUtil
import org.apache.griffin.measure.utils.JsonUtil
import org.apache.griffin.measure.utils.ParamUtil._

/**
 * sink metric and record to hdfs
 */
case class HdfsSink(config: Map[String, Any], metricName: String, timeStamp: Long) extends Sink {

  val block: Boolean = true

  val PathKey = "path"
  val MaxPersistLines = "max.persist.lines"
  val MaxLinesPerFile = "max.lines.per.file"

  val parentPath: String = config.getOrElse(PathKey, "").toString
  val maxPersistLines: Int = config.getInt(MaxPersistLines, -1)
  val maxLinesPerFile: Int = math.min(config.getInt(MaxLinesPerFile, 10000), 1000000)

  val StartFile: String = filePath("_START")
  val FinishFile: String = filePath("_FINISH")
  val MetricsFile: String = filePath("_METRICS")

  val LogFile: String = filePath("_LOG")

  var _init = true

  def available(): Boolean = {
    parentPath.nonEmpty
  }

  private def logHead: String = {
    if (_init) {
      _init = false
      val dt = new Date(timeStamp)
      s"================ log of $dt ================\n"
    } else ""
  }

  private def timeHead(rt: Long): String = {
    val dt = new Date(rt)
    s"--- $dt ---\n"
  }

  private def logWrap(rt: Long, msg: String): String = {
    logHead + timeHead(rt) + s"$msg\n\n"
  }

  protected def filePath(file: String): String = {
    HdfsUtil.getHdfsFilePath(parentPath, s"$metricName/$timeStamp/$file")
  }

  protected def withSuffix(path: String, suffix: String): String = {
    s"$path.$suffix"
  }

  def start(msg: String): Unit = {
    try {
      HdfsUtil.writeContent(StartFile, msg)
    } catch {
      case e: Throwable => error(e.getMessage, e)
    }
  }

  def finish(): Unit = {
    try {
      HdfsUtil.createEmptyFile(FinishFile)
    } catch {
      case e: Throwable => error(e.getMessage, e)
    }
  }

  def log(rt: Long, msg: String): Unit = {
    try {
      val logStr = logWrap(rt, msg)
      HdfsUtil.withHdfsFile(LogFile) { out =>
        out.write(logStr.getBytes("utf-8"))
      }
    } catch {
      case e: Throwable => error(e.getMessage, e)
    }
  }

  private def getHdfsPath(path: String, groupId: Int): String = {
    HdfsUtil.getHdfsFilePath(path, s"$groupId")
  }

  private def clearOldRecords(path: String): Unit = {
    HdfsUtil.deleteHdfsPath(path)
  }

  def sinkRecords(records: RDD[String], name: String): Unit = {
    val path = filePath(name)
    clearOldRecords(path)
    try {
      val recordCount = records.count

      val count =
        if (maxPersistLines < 0) recordCount else scala.math.min(maxPersistLines, recordCount)

      if (count > 0) {
        val groupCount = ((count - 1) / maxLinesPerFile + 1).toInt
        if (groupCount <= 1) {
          val recs = records.take(count.toInt)
          sinkRecords2Hdfs(path, recs)
        } else {
          val groupedRecords: RDD[(Long, Iterable[String])] =
            records.zipWithIndex
              .flatMap { r =>
                val gid = r._2 / maxLinesPerFile
                if (gid < groupCount) Some((gid, r._1)) else None
              }
              .groupByKey()
          groupedRecords.foreach { group =>
            val (gid, recs) = group
            val hdfsPath = if (gid == 0) path else withSuffix(path, gid.toString)
            sinkRecords2Hdfs(hdfsPath, recs)
          }
        }
      }
    } catch {
      case e: Throwable => error(e.getMessage, e)
    }
  }

  def sinkRecords(records: Iterable[String], name: String): Unit = {
    val path = filePath(name)
    clearOldRecords(path)
    try {
      val recordCount = records.size

      val count =
        if (maxPersistLines < 0) recordCount else scala.math.min(maxPersistLines, recordCount)

      if (count > 0) {
        val groupCount = (count - 1) / maxLinesPerFile + 1
        if (groupCount <= 1) {
          val recs = records.take(count.toInt)
          sinkRecords2Hdfs(path, recs)
        } else {
          val groupedRecords = records.grouped(maxLinesPerFile).zipWithIndex
          groupedRecords.take(groupCount).foreach { group =>
            val (recs, gid) = group
            val hdfsPath = getHdfsPath(path, gid)
            sinkRecords2Hdfs(hdfsPath, recs)
          }
        }
      }
    } catch {
      case e: Throwable => error(e.getMessage, e)
    }
  }

  def sinkMetrics(metrics: Map[String, Any]): Unit = {
    try {
      val json = JsonUtil.toJson(metrics)
      sinkRecords2Hdfs(MetricsFile, json :: Nil)
    } catch {
      case e: Throwable => error(e.getMessage, e)
    }
  }

  private def sinkRecords2Hdfs(hdfsPath: String, records: Iterable[String]): Unit = {
    try {
      HdfsUtil.withHdfsFile(hdfsPath, appendIfExists = false) { out =>
        records.map { record =>
          out.write((record + "\n").getBytes("utf-8"))
        }
      }
    } catch {
      case e: Throwable => error(e.getMessage, e)
    }
  }

}