package aoc.y2019.intcode

import cats.data.{Kleisli, State}

case class OperandMode(get: Kleisli[Operation, BigInt, BigInt], set: Kleisli[Operation, (BigInt, BigInt), Unit])

object OperandMode {

  val position: OperandMode = OperandMode(
    Kleisli(Machine.get),
    Kleisli { case (address, value) => Machine.set(address, value) }
  )
  val immediate: OperandMode = OperandMode(
    Kleisli(State.pure),
    Kleisli(_ => throw new IllegalArgumentException("Cannot set in immediate mode!"))
  )
  val relative: OperandMode = OperandMode(
    Kleisli { address =>
      for {
        offset <- Machine.getOffset
        value <- Machine.get(address + offset)
      } yield value
    },
    Kleisli { case (address, value) =>
      for {
        offset <- Machine.getOffset
        set <- Machine.set(address + offset, value)
      } yield set
    }
  )

  val defaultOperandModes: Map[Int, OperandMode] = Map(
    0 -> position,
    1 -> immediate,
    2 -> relative,
  )

}