package lu.foyer
package contracts

import zio.*

class ContractReducer() extends Reducer[ContractEvent, ContractState]:

  override val fromEmpty =
    case e: ContractEvent.Subscribed => ContractState.subscribe(e)

  override val fromState =
    case (s: ContractState.Actif, e: ContractEvent.Amended)    => s.amend(e)
    case (s: ContractState.Actif, _: ContractEvent.Terminated) => s.terminate()

    case (s: ContractState.PendingSubscription, e: ContractEvent.Amended)    => s.amend(e)
    case (s: ContractState.PendingSubscription, _: ContractEvent.Approved)   => s.approve()
    case (s: ContractState.PendingSubscription, _: ContractEvent.Rejected)   => s.reject()
    case (s: ContractState.PendingSubscription, _: ContractEvent.Terminated) => s.terminate()

    case (s: ContractState.PendingAmendment, e: ContractEvent.Amended)    => s.amend(e)
    case (s: ContractState.PendingAmendment, _: ContractEvent.Approved)   => s.approve()
    case (s: ContractState.PendingAmendment, _: ContractEvent.Rejected)   => s.reject()
    case (s: ContractState.PendingAmendment, _: ContractEvent.Terminated) => s.terminate()

object ContractReducer:
  val layer: ULayer[Reducer[ContractEvent, ContractState]] = ZLayer.succeed(ContractReducer())