package com.sandro.app

import org.apache.spark.SparkConf
import org.apache.spark.sql.SparkSession
import org.slf4j.Logger
import scala.collection.mutable

trait SparkApp extends Serializable {

  /** Utility to parse the arguments.properties using the
   * property json in the classpath identified from
   * the variable propertyPath
   *
   * @param args the list of arguments.properties
   */
  def parseArguments(args: Array[String]): mutable.Map[String, String] = {
    SparkUtility.parseArguments(args)
  }

  /** Here all the spark applications runs this method
   * where the whole logic of the spark node is defined
   */
  def run(): Unit
}

abstract class AbstractScalaApplication(val args: Array[String],
                                        log: Logger
                                       ) extends SparkApp {

  var argumentMap: mutable.Map[String, String] = _


  var spark: SparkSession = _

  def initialize(): SparkApp = {
    argumentMap = parseArguments(args)
    spark = createSparkSession()
    spark.sparkContext.setLogLevel("WARN")
    this
  }

  /** Utility for creating a spark session starting from parser
   *
   * @return a spark Session
   */
  private def createSparkSession(): SparkSession = {
    require(argumentMap != null)

    val conf: SparkConf = new SparkConf()
    val master = argumentMap("master")
    log.info(s"Creating Spark session: Master: $master")
    SparkSession
      .builder()
      .config(conf)
      .appName(getClass.getSimpleName)
      .master(master)
      .getOrCreate()
  }

}