package net.tz.spss

import com.bedatadriven.spss.SpssDataFileReader

sealed trait SpssValue

sealed trait Missing extends SpssValue

abstract class Value[T] extends SpssValue {

  def v: T

}

abstract class MissingValue[T] extends Value[T]

case class StringValue(v: String) extends Value[String]

case class DoubleValue(v: Double) extends Value[Double]

case object SystemMissing extends Missing

// ??? case class MissingString(v: String) extends MissingValue[String]

case class MissingDouble(v: Double) extends MissingValue[Double]

object SpssValue {

  def apply(r: SpssDataFileReader, variable: SpssVariable): SpssValue = {

    val i = variable.index

    if (r.isSystemMissing(i))

      SystemMissing

    else

      Option(r.getDoubleValue(i)) map(x =>

        if (r.isValueMissing(i, x)) MissingDouble(x) else DoubleValue(x)

        ) orElse (Option(r.getStringValue(i)) map StringValue

        ) getOrElse SystemMissing

  }

}