build.sbt

import java.io.PrintWriter

enablePlugins(ScalaJSPlugin)

name := "slinky-readwrite"

libraryDependencies += "org.scala-lang" % "scala-reflect" % scalaVersion.value
libraryDependencies += "org.scala-lang" % "scala-compiler" % scalaVersion.value

sourceGenerators in Compile += Def.task {
  val genFile = (sourceManaged in Compile).value / "GenWriters.scala"
  (sourceManaged in Compile).value.mkdirs()
  genFile.createNewFile()
  val out = new PrintWriter(genFile)
  val gens = (0 to 22).map { n =>
    s"""implicit def function$n[${(0 until n).map(i => s"I$i, ").mkString} O]
       |              (implicit ${(0 until n).map(i => s"i${i}Reader: Reader[I$i], ").mkString} oWriter: Writer[O]): Writer[(${(0 until n).map(i => s"I$i").mkString(", ")}) => O] = s => {
       |  val fn: js.Function$n[${(0 until n).map(_ => "js.Object, ").mkString} js.Object] = (${(0 until n).map(i => s"i$i: js.Object").mkString(", ")}) => {
       |    oWriter.write(s(${(0 until n).map(i => s"i${i}Reader.read(i$i)").mkString(", ")}))
       |  }
       |
       |  fn.asInstanceOf[js.Object]
       |}""".stripMargin
  }

  out.println(
    s"""package slinky.readwrite
       |
       |import scala.scalajs.js
       |
       |trait Writer[P] {
       |  def write(p: P): js.Object
       |}
       |
       |object Writer extends CoreWriters {
       |  ${gens.mkString("\n")}
       |}""".stripMargin)

  out.close()
  Seq(genFile)
}

sourceGenerators in Compile += Def.task {
  val genFile = (sourceManaged in Compile).value / "GenReaders.scala"
  (sourceManaged in Compile).value.mkdirs()
  genFile.createNewFile()
  val out = new PrintWriter(genFile)
  val gens = (0 to 22).map { n =>
    s"""implicit def function$n[${(0 until n).map(i => s"I$i, ").mkString} O]
       |              (implicit ${(0 until n).map(i => s"i${i}Writer: Writer[I$i], ").mkString} oReader: Reader[O]): Reader[(${(0 until n).map(i => s"I$i").mkString(", ")}) => O] = s => {
       |  val fn = s.asInstanceOf[js.Function$n[${(0 until n).map(_ => "js.Object, ").mkString} js.Object]]
       |  (${(0 until n).map(i => s"i$i: I$i").mkString(", ")}) => {
       |    oReader.read(fn(${(0 until n).map(i => s"i${i}Writer.write(i$i)").mkString(", ")}))
       |  }
       |}""".stripMargin
  }

  out.println(
    s"""package slinky.readwrite
       |
       |import scala.scalajs.js
       |
       |trait Reader[P] {
       |  def read(o: js.Object): P = {
       |    val ret = if (js.typeOf(o) == "object" && o != null && !js.isUndefined(o.asInstanceOf[js.Dynamic].__)) {
       |      o.asInstanceOf[js.Dynamic].__.asInstanceOf[P]
       |    } else {
       |      forceRead(o)
       |    }
       |
       |    if (ret.isInstanceOf[WithRaw]) {
       |      ret.asInstanceOf[js.Dynamic].__slinky_raw = o
       |    }
       |
       |    ret
       |  }
       |
       |  protected def forceRead(o: js.Object): P
       |}
       |
       |trait AlwaysReadReader[P] extends Reader[P] {
       |  override def read(o: js.Object): P = forceRead(o)
       |  protected def forceRead(o: js.Object): P
       |}
       |
       |object Reader extends CoreReaders {
       |  ${gens.mkString("\n")}
       |}""".stripMargin)

  out.close()
  Seq(genFile)
}