ServerOpticsTest.scala

package monocle

import monocle.Lens
import monocle.syntax.all.*

import java.time.{Clock, Instant}
import scala.collection.immutable.*

//for an intro to Monocle see the video https://twitter.com/bblfish/status/1413758476896153601
// and the thread of references above it.
// and the documentation https://www.optics.dev/Monocle/
// note this is Scala 3 code

sealed trait Resource[T] {
	def content: T

	def created: Instant
	
	//def modified: Instant
}

def now: Instant = Clock.systemUTC().instant()

case class Container(
	content: Map[String, Resource[_]] = Map(),
	created: Instant = now
) extends Resource[Map[String, Resource[_]]]

// of course there could be many more Resources (eg. RDF Graphs, Pictures, etc)
case class TextResource(
	content: String,
	created: Instant = now
) extends Resource[String]

object Server {
	val root = Container()

	val contents = Lens[Container, Map[String, Resource[_]]](_.content){ newmap =>
		cont => cont.copy(content = newmap)
	}

	def POST(slug: String, text: String): Container => Container = contents.modify(oldMap =>
		oldMap + (slug -> TextResource(text))
	)
}