SqlBuilderPoC.scala

object SqlBuilderPoC {

  class ResultRow
  trait Parser[T] {
    def parse(row: ResultRow): T
  }


  trait Record[T]
  trait Table[P, T, R <: Record[T]] {
    def build(t: T): R
    def parser: Parser[T]

    def all: Seq[Field[_]]
  }


  case class Field[T](name: String, t: FieldType[T])
  case class FieldType[T](dbType: String, convert: Any => T)


  case class Session(id: Int, sessId: String) extends Record[(Int, String)]

  object SessionTable extends Table[Int, (Int, String), Session] {

    val id = Field("id", FieldType("INT", _.toString.toInt))
    val sessionId = Field("session_id", FieldType("VARCHAR(100)", _.toString))

    override def build(t: (Int, String)): Session = (Session.apply _).tupled(t)

    override def parser: Parser[(Int, String)] = (row: ResultRow) => ???

    override def all: Seq[Field[_]] = Seq(id, sessionId)
  }

  def select[T, R <: Record[T]](field: Field[T], table: Table[_, T, R]): R = ???
  def select[T1, T2, T: (T1, T2), R <: Record[T]](field1: Field[T1], field2: Field[T2], table: Table[_, T, R]): R = ???
  def select[T1, T2, T3, T: (T1, T2, T3), R <: Record[T]](field1: Field[T1], field2: Field[T2], field3: Field[T3], table: Table[_, T, R]): R = ???

  def select[T, R <: Record[T]](table: Table[_, T, R]): Seq[R] = {
    table.all // TODO make query
    val sql = "SELECT *"

    val result: Seq[ResultRow] = Nil
    result
      .map(table.parser.parse)
      .map(table.build)
  }


  val a = select(SessionTable)

}