filter.scala

package test

// Type definitions
object Types {
  type Tag = String
}
import Types._

// Marker definitions
case class OperatingHours(hours: String)
case class Metadata(url: Option[String], hours: Option[OperatingHours])
case class Marker(id: String, name: String, lat: Double, lng: Double, symbol: String, tags: List[Tag]=List.empty[Tag], metadata: Option[Metadata]=None)

// Filter definntions
trait FilterPrimitive
trait FilterLogic extends FilterPrimitive

case class TagFilter(tag: String) extends FilterPrimitive
case class NotFilter(filter: FilterPrimitive) extends FilterLogic
case class AndFilter[F <: FilterPrimitive, G <: FilterPrimitive](left: F, right: G) extends FilterLogic
case class OrFilter(left: FilterPrimitive, right: FilterPrimitive) extends FilterLogic

trait FilterConversions {
  implicit def TagFilterHandler(m: Marker, f: TagFilter) = m.tags contains f.tag
  implicit def AndFilterHandler[F <: FilterPrimitive, G <: FilterPrimitive](m: Marker, f: AndFilter[F, G])(implicit F: ((Marker, F) => Boolean), G: ((Marker, G) => Boolean)) = 
    Filter(m, f.left) && Filter(m, f.right)
}

object Filter {
  def apply[F](m: Marker, f: F)(implicit filterHandler: ((Marker, F) => Boolean)): Boolean = {
    filterHandler(m, f)
  }

  def indirectApply[F <: FilterPrimitive](m: Marker, f: F)(implicit filterHandler: ((Marker, F) => Boolean)) = 
    apply(m, f) // Why doesn't this work? answer, needs implicit
}

object MyApp extends App with FilterConversions {
  var f = AndFilter(TagFilter("food-truck"), NotFilter(TagFilter("restaurant")))
  var m = Marker(id="0001", name="Abu Nawas", lat=22.399474275956216, lng=39.08273218518074, symbol="/images/restaurants/logo_abunawas-180x100.png", tags=List("stationary", "restaurant"))

  println(s"Filter: ${Filter(m, TagFilter("stationary"))}")
  println(s"Filter: ${Filter(m, TagFilter("mobile"))}")
}