ZIO Temporal

import zio._
import zio.temporal._
import zio.temporal.workflow._
import zio.temporal.protobuf.syntax._

// Business process as an interface
@workflowInterface
trait PaymentWorkflow {

  @workflowMethod
  def proceed(transaction: ProceedTransactionCommand): TransactionView

  @queryMethod
  def isFinished(): Boolean

  @signalMethod
  def confirmTransaction(command: ConfirmTransactionCommand): Unit
}

// Client-side code
class TemporalPaymentService(workflowClient: ZWorkflowClient) {
  def createPayment(sender: UUID, receiver: UUID, amount: BigDecimal) =
    for {
      transactionId <- ZIO.randomWith(_.nextUUID)
      paymentWorkflow <- workflowClient.newWorkflowStub[PaymentWorkflow](
                           ZWorkflowOptions
                             .withWorkflowId(transactionId.toString)
                             .withTaskQueue("payments")
                             // Built-in timeouts
                             .withWorkflowExecutionTimeout(6.minutes)
                             .withWorkflowRunTimeout(1.minute)
                             // Built-in retries
                             .withRetryOptions(
                               ZRetryOptions.default.withMaximumAttempts(5)
                             )
                         )
      // Start the business process
      _ <- ZWorkflowStub.start(
             paymentWorkflow.proceed(
               ProceedTransactionCommand(
                 id = transactionId,
                 sender = sender,
                 receiver = receiver,
                 amount = amount
               )
             )
           )
    } yield transactionId

  def confirmTransaction(transactionId: UUID, confirmationCode: String) =
    for {
      // Get the running business process
      workflowStub <- workflowClient.newWorkflowStub[PaymentWorkflow](
        workflowId = transactionId.toString
      )
      // Check the business process state
      isFinished <- ZWorkflowStub.query(
                      workflowStub.isFinished()
                    )
      _ <- ZIO.unless(isFinished) {
             // Interact with a running workflow!
             ZWorkflowStub.signal(
               workflowStub.confirmTransaction(
                 ConfirmTransactionCommand(id = transactionId, confirmationCode)
               )
             )
           }
    } yield ()
}