package eu.dnetlib.doiboost.crossref

import eu.dnetlib.dhp.application.ArgumentApplicationParser
import org.apache.hadoop.io.compress.GzipCodec
import org.apache.spark.{SparkConf, SparkContext}
import org.apache.spark.sql.{Encoder, Encoders, SaveMode, SparkSession}
import org.json4s
import org.json4s.DefaultFormats
import org.json4s.JsonAST.JArray
import org.json4s.jackson.JsonMethods.{compact, parse, render}
import org.slf4j.{Logger, LoggerFactory}

import scala.io.Source

object UnpackCrtossrefEntries {

  val log: Logger = LoggerFactory.getLogger(UnpackCrtossrefEntries.getClass)




  def extractDump(input:String):List[String] = {
    implicit lazy val formats: DefaultFormats.type = org.json4s.DefaultFormats
    lazy val json: json4s.JValue = parse(input)

    val a = (json \ "items").extract[JArray]
    a.arr.map(s => compact(render(s)))


  }



  def main(args: Array[String]): Unit = {
    val conf = new SparkConf
    val parser = new ArgumentApplicationParser(Source.fromInputStream(getClass.getResourceAsStream("/eu/dnetlib/dhp/doiboost/crossref_dump_reader/generate_dataset_params.json")).mkString)
    parser.parseArgument(args)
    val master = parser.get("master")
    val sourcePath = parser.get("sourcePath")
    val targetPath = parser.get("targetPath")

    val spark: SparkSession = SparkSession.builder().config(conf)
      .appName(UnpackCrtossrefEntries.getClass.getSimpleName)
      .master(master)
      .getOrCreate()
    val sc: SparkContext = spark.sparkContext

    sc.wholeTextFiles(sourcePath,6000).flatMap(d =>extractDump(d._2))
      .saveAsTextFile(targetPath, classOf[GzipCodec])


  }

}