package tf.bug.example

import java.io.File

import cats._
import cats.data._
import cats.implicits._
import cats.effect.IO
import tf.bug.cataquack.{Read, Storage}
import tf.bug.cataquack.implicits._

import scala.io.Source

object Example {

  def main(args: Array[String]): Unit = {
    val f: File = new File("counter.txt")
    val s: Storage[IO, String] = (key: String) => IO {
      Source.fromFile(f).getLines().find(_.startsWith(key ++ " ")) match {
        case Some(line) => line.drop(key.length + 1)
        case None => throw new IllegalArgumentException(s"No such key: $key")
      }
    }
    val count = readCount(s)
    val desc = readDescription(s)
    val pr = for {
      c <- count
      d <- desc
    } yield println(s"$d: $c")
    pr.unsafeRunSync()
  }

  case class Counter(n: Long)
  case class Description(n: String)

  def readCount[F[_]: Functor, T](s: Storage[F, T])(implicit read: Read[T, Long]): F[Long] = {
    s.get("count").map(read.apply)
  }

  def readDescription[F[_]: Functor, T](s: Storage[F, T])(implicit read: Read[T, String]): F[String] = {
    s.get("desc").map(read.apply)
  }

  implicit def readStringLong: Read[String, Long] = (i: String) => i.toLong

}