package jp.ymir.taskReporter.core
import scala.collection._
import scala.collection.immutable.StringLike

object TSV {
  type Header = Seq[Symbol]
  type Field  = String
  type Record = Map[Symbol, Field]

  def decode[A: FromRecord](tsv: StringLike[_]): Seq[A] = {
    val lines  = tsv.split('\n').filter(!_.isEmpty)
    val header = lines.head.split('\t').map(Symbol(_))
    val body   = lines.tail.map(line => (header zip line.split('\t')).toMap)
    return body.map(implicitly[FromRecord[A]].parseRecord)
  }

  trait FromRecord[A] {
    def parseRecord(r: Record): A
  }

  trait FromField[A] {
    def parseField(f: Field): A
  }
  def parseField[A: FromField](f: Field): A
    = implicitly[FromField[A]].parseField(f)

  trait ToRecord[A] {
    def toRecord(a: A): Record
  }

  trait ToField[A] {
    def toField(a: A): Field
  }

  // Option[A]
  implicit def OptionFromField[A: FromField] = new FromField[Option[A]] {
    def parseField(f: Field): Option[A] = {
      if (f.isEmpty) {
        return None
      }
      else {
        return Some(implicitly[FromField[A]].parseField(f))
      }
    }
  }

  // String
  implicit def StringFromField = new FromField[String] {
    def parseField(f: Field): String = f
  }

  // Int
  implicit def IntFromField = new FromField[Int] {
    def parseField(f: Field): Int = f.toInt
  }
}