// RUN: %target-swift-emit-silgen -target %target-swift-5.7-abi-triple -parse-as-library %s | %FileCheck %s
// RUN: %target-run-simple-swift( -target %target-swift-5.7-abi-triple -parse-as-library)

// REQUIRES: executable_test
// REQUIRES: concurrency
// REQUIRES: distributed

// rdar://76038845
// UNSUPPORTED: use_os_stdlib
// UNSUPPORTED: back_deployment_runtime

import Distributed

distributed actor Philosopher {

  distributed func think() {
  }

  // CHECK: sil hidden [ossa] @$s28distributed_actor_self_calls11PhilosopherC10stopEatingyyF : $@convention(method) (@sil_isolated @guaranteed Philosopher) -> () {
  func stopEating() { // NOTE: marking this async solves the issue; we find the async context then
    self.think()

    // Confirm we're calling the function directly, rather than the distributed thunk
    // Calling the thunk would crash, because it is async (and throws), and as we're not in an async function
    // trying to get the async context to call the async thunk would fail here.
    //
    // CHECK:        // function_ref Philosopher.think()
    // CHECK-NEXT:   [[E:%[0-9]+]] = function_ref @$s28distributed_actor_self_calls11PhilosopherC5thinkyyF : $@convention(method) (@sil_isolated @guaranteed Philosopher) -> ()
  }
}


// ==== Fake Transport ---------------------------------------------------------

struct ActorAddress: Sendable, Hashable, Codable {
  let address: String
  init(parse address : String) {
    self.address = address
  }
}

struct FakeActorSystem: DistributedActorSystem {
  typealias ActorID = ActorAddress
  typealias InvocationDecoder = FakeInvocationDecoder
  typealias InvocationEncoder = FakeInvocationEncoder
  typealias SerializationRequirement = Codable
  typealias ResultHandler = FakeResultHandler

  func resolve<Act>(id: ActorID, as actorType: Act.Type) throws -> Act?
      where Act: DistributedActor,
            Act.ID == ActorID {
    return nil
  }

  func assignID<Act>(_ actorType: Act.Type) -> ActorID
      where Act: DistributedActor {
    ActorAddress(parse: "")
  }

  func actorReady<Act>(_ actor: Act)
      where Act: DistributedActor {
    print("\(#function):\(actor)")
  }

  func resignID(_ id: ActorID) {}

  func makeInvocationEncoder() -> InvocationEncoder {
    .init()
  }

  func remoteCall<Act, Err, Res>(
    on actor: Act,
    target: RemoteCallTarget,
    invocation invocationEncoder: inout InvocationEncoder,
    throwing: Err.Type,
    returning: Res.Type
  ) async throws -> Res
    where Act: DistributedActor,
          Act.ID == ActorID,
          Err: Error,
          Res: SerializationRequirement {
    fatalError("Not implemented")
  }

  func remoteCallVoid<Act, Err>(
    on actor: Act,
    target: RemoteCallTarget,
    invocation invocationEncoder: inout InvocationEncoder,
    throwing: Err.Type
  ) async throws
    where Act: DistributedActor,
          Act.ID == ActorID,
          Err: Error {
    fatalError("Not implemented")
  }
}

// === Sending / encoding -------------------------------------------------
struct FakeInvocationEncoder: DistributedTargetInvocationEncoder {
  typealias SerializationRequirement = Codable

  mutating func recordGenericSubstitution<T>(_ type: T.Type) throws {}
  mutating func recordArgument<Value: SerializationRequirement>(_ argument: RemoteCallArgument<Value>) throws {}
  mutating func recordReturnType<R: SerializationRequirement>(_ type: R.Type) throws {}
  mutating func recordErrorType<E: Error>(_ type: E.Type) throws {}
  mutating func doneRecording() throws {}
}

// === Receiving / decoding -------------------------------------------------
class FakeInvocationDecoder : DistributedTargetInvocationDecoder {
  typealias SerializationRequirement = Codable

  func decodeGenericSubstitutions() throws -> [Any.Type] { [] }
  func decodeNextArgument<Argument: SerializationRequirement>() throws -> Argument { fatalError() }
  func decodeReturnType() throws -> Any.Type? { nil }
  func decodeErrorType() throws -> Any.Type? { nil }
}

public struct FakeResultHandler: DistributedTargetInvocationResultHandler {
  public typealias SerializationRequirement = Codable

  public func onReturn<Success: SerializationRequirement>(value: Success) async throws {
    fatalError("Not implemented: \(#function)")
  }

  public func onReturnVoid() async throws {
    fatalError("Not implemented: \(#function)")
  }

  public func onThrow<Err: Error>(error: Err) async throws {
    fatalError("Not implemented: \(#function)")
  }
}

typealias DefaultDistributedActorSystem = FakeActorSystem

// ==== Execute ----------------------------------------------------------------

func test(system: FakeActorSystem) async {
  _ = Philosopher(actorSystem: system)
}

@main struct Main {
  static func main() async {
    await test(system: FakeActorSystem())
  }
}