package mi.scala.utils.abstractions

import cats.kernel.Monoid
import mi.scala.utils.math.Interval

object Mapping {

  implicit def toAB[A, B](mapping: Mapping[A, B]): A => B = mapping.fun

  case class IntervalMapping[A, +B](interval: Interval[A], f: Mapping[A, B])(implicit m: Monoid[B]) extends Mapping[A, B] with OptionMapping[A, B] {
    def funOption(v: A): Option[B] = Option.when(interval.contains(v))(f(v))

    def fun(v: A): B = funOption(v).getOrElse(m.empty)
  }


  case class CombinedMapping[-A, +B](mappings: Seq[Mapping[A, B]])(implicit m: Monoid[B]) extends Mapping[A, B] {
    override def fun(v: A): B = m.combineAll(mappings.map(_.fun(v)))
  }

  case class CombinedOptionMapping[-A, +B](mappings: Seq[OptionMapping[A, B]])(implicit m: Monoid[B]) extends OptionMapping[A, B] {
    override def funOption(v: A): Option[B] = mappings.flatMap(m => m.funOption(v)).reduceOption(m.combine)
  }

}

trait Mapping[-A, +B] {
  def fun(v: A): B
}

trait OptionMapping[-A, +B] {
  def funOption(v: A): Option[B]
}
/////использование
 val lodLevels:Mapping[Float, Int] = CombinedMapping(Seq(
      IntervalMapping[Float,Int](Interval(Float.MinValue, 0, containsEnd = false ), _ => 0),
      IntervalMapping[Float,Int](Interval(0, 64, containsEnd = false ), _ => 0),
      IntervalMapping[Float,Int](Interval(64, 128, containsEnd = false ), _ => 1),
      IntervalMapping[Float,Int](Interval(128, 256, containsEnd = false ), _ => 2),
      IntervalMapping[Float,Int](Interval(256, 512, containsEnd = false ), _ => 3),
      IntervalMapping[Float,Int](Interval(512, 768, containsEnd = false ), _ => 4),
      IntervalMapping[Float,Int](Interval(768, 1024, containsEnd = false ), _ => 5),
      IntervalMapping[Float,Int](Interval(1024, 1536, containsEnd = false ), _ => 6),
      IntervalMapping[Float,Int](Interval(1536, 2048, containsEnd = false ), _ => 7),
      IntervalMapping[Float,Int](Interval(2048, 4096, containsEnd = false ), _ => 8),
      IntervalMapping[Float,Int](Interval(4096, 8192, containsEnd = false ), _ => 9),
      IntervalMapping[Float,Int](Interval(8192, Float.MaxValue, containsEnd = true), _ => 10)
    ))