foyer-dsi-assure-2035/api/src/lu/foyer/CommandEngineController.scala

package lu.foyer

import zio.*
import zio.http.*
import zio.http.codec.*
import zio.http.codec.PathCodec.path
import zio.http.endpoint.*
import zio.schema.*

trait CommandEngineController[Command, Event: Schema, State: Schema] extends JsonApiController:

  def commandEngine: CommandEngine[Command, Event, State]

  private lazy val fetchMany =
    Endpoint(Method.GET / entityName)
      .query(HttpCodec.query[Page])
      .jsonApiMany[State]

  private lazy val fetchOne =
    Endpoint(Method.GET / entityName / string("entityId"))
      .jsonApiOne[State]

  private lazy val fetchEventsMany =
    Endpoint(Method.GET / entityName / string("entityId") / "events")
      .query(HttpCodec.query[Page])
      .jsonApiMany[Event]

  private lazy val fetchEventsOne =
    Endpoint(Method.GET / entityName / string("entityId") / "events" / string("eventId"))
      .jsonApiOne[Event]

  private def generateCommands = commandEngine.handlers.map(handler =>
    if handler.isCreate then generateCreateCommand(handler)
    else generateUpdateCommand(handler)
  )

  private def generateCreateCommand(handler: CommandHandler[Command, Event, State]) =
    given Schema[Command] = handler.commandSchema.asInstanceOf[Schema[Command]]
    val endpoint = Endpoint(Method.POST / entityName / "commands" / handler.name)
      .in[Command]
      .jsonApiOneWithStatus[Event](Status.Created)
    val route = endpoint.implementJsonApiOneEvent(command =>
      for
        entityId <- Random.nextUUID
        (event, _) <- commandEngine
                        .handleCommand(command, handler.name, entityId.toString)
      yield Some(event)
    )
    (endpoint, route)

  private def generateUpdateCommand(handler: CommandHandler[Command, Event, State]) =
    given Schema[Command] = handler.commandSchema.asInstanceOf[Schema[Command]]
    val endpoint = Endpoint(
      Method.PUT / entityName / string("entityId") / "commands" / handler.name
    )
      .in[Command]
      .jsonApiOne[Event]
    val route = endpoint.implementJsonApiOneEvent((entityId, command) =>
      for (event, _) <- commandEngine
                          .handleCommand(command, handler.name, entityId)
      yield Some(event)
    )
    (endpoint, route)

  private lazy val (commands, commandsRoutes) = generateCommands.unzip

  private lazy val fetchManyRoute =
    fetchMany.implementJsonApiManyEntity(commandEngine.stateRepo.fetchMany)

  private lazy val fetchOneRoute =
    fetchOne.implementJsonApiOneEntity(commandEngine.stateRepo.fetchOne)

  private lazy val fetchEventsManyRoute =
    fetchEventsMany.implementJsonApiManyEvent(commandEngine.eventRepo.fetchMany(_, _))

  private lazy val fetchEventsOneRoute =
    fetchEventsOne.implementJsonApiOneEvent(commandEngine.eventRepo.fetchOne(_, _))

  lazy val endpoints = List(
    fetchMany,
    fetchOne,
    fetchEventsMany,
    fetchEventsOne
  ) ++ commands

  lazy val routes = (Routes(
    fetchManyRoute,
    fetchOneRoute,
    fetchEventsManyRoute,
    fetchEventsOneRoute
  ) ++ Routes.fromIterable(commandsRoutes)) @@ proxyHeadersAspect

end CommandEngineController