(* This file is part of Lwt, released under the MIT license. See LICENSE.md for
   details, or visit https://github.com/ocsigen/lwt/blob/master/LICENSE.md. *)



open Test
open Lwt.Infix

(* Note: due to the time delays in the tests of this suite, it could really
   benefit from an option to run tests in parallel. *)

let suite = suite "Lwt_timeout" [
  test "basic" begin fun () ->
    let p, r = Lwt.wait () in

    let start_time = Unix.gettimeofday () in

    let timeout =
      Lwt_timeout.create 1 (fun () ->
        let delta = Unix.gettimeofday () -. start_time in
        Lwt.wakeup_later r delta)
    in
    Lwt_timeout.start timeout;

    p >|= fun delta ->
    instrument (delta >= 2. && delta < 3.)
      "Lwt_timeout: basic: %f %f" start_time delta
    (* The above is a bug of the current implementation: it always gives too
       long a timeout. *)
  end;

  test "not started" begin fun () ->
    let p, r = Lwt.wait () in

    Lwt_timeout.create 1 (fun () ->
      Lwt.wakeup_later r false)
    |> ignore;

    Lwt.async (fun () ->
      Lwt_unix.sleep 3. >|= fun () ->
      Lwt.wakeup_later r true);

    p
  end;

  test "double start" begin fun () ->
    let completions = ref 0 in

    let timeout =
      Lwt_timeout.create 1 (fun () ->
        completions := !completions + 1)
    in
    Lwt_timeout.start timeout;
    Lwt_timeout.start timeout;

    Lwt_unix.sleep 3. >|= fun () ->
    instrument (!completions = 1) "Lwt_timeout: double start: %i" !completions
  end;

  test "restart" begin fun () ->
    let p, r = Lwt.wait () in

    let completions = ref 0 in

    (* A dummy timeout, just to set up the reference. *)
    let timeout = ref (Lwt_timeout.create 1 ignore) in

    timeout :=
      Lwt_timeout.create 1 (fun () ->
        completions := !completions + 1;
        if !completions < 2 then
          Lwt_timeout.start !timeout
        else
          Lwt.wakeup_later r true);
    Lwt_timeout.start !timeout;

    p
  end;

  test "stop" begin fun () ->
    let p, r = Lwt.wait () in

    let timeout =
      Lwt_timeout.create 1 (fun () ->
        Lwt.wakeup_later r false)
    in
    Lwt_timeout.start timeout;
    Lwt_timeout.stop timeout;

    Lwt.async (fun () ->
      Lwt_unix.sleep 3. >|= fun () ->
      Lwt.wakeup_later r true);

    p
  end;

  test "stop when not stopped" begin fun () ->
    Lwt_timeout.create 1 ignore
    |> Lwt_timeout.stop;

    Lwt.return true
  end;

  test "invalid delay" begin fun () ->
    try
      ignore (Lwt_timeout.create 0 ignore);
      Lwt.return false
    with Invalid_argument _ ->
      Lwt.return true
  end;

  test "change" begin fun () ->
    let p, r = Lwt.wait () in

    let start_time = Unix.gettimeofday () in

    let timeout =
      Lwt_timeout.create 5 (fun () ->
        let delta = Unix.gettimeofday () -. start_time in
        Lwt.wakeup_later r delta)
    in
    Lwt_timeout.change timeout 1;
    Lwt_timeout.start timeout;

    p >|= fun delta ->
    instrument (delta >= 1.9 && delta < 3.1)
      "Lwt_timeout: change: %f %f" start_time delta
  end;

  test "change does not start" begin fun () ->
    let p, r = Lwt.wait () in

    let timeout =
      Lwt_timeout.create 1 (fun () ->
        Lwt.wakeup_later r false)
    in
    Lwt_timeout.change timeout 1;

    Lwt.async (fun () ->
      Lwt_unix.sleep 3. >|= fun () ->
      Lwt.wakeup_later r true);

    p
  end;

  test "change after start" begin fun () ->
    let p, r = Lwt.wait () in

    let start_time = Unix.gettimeofday () in

    let timeout =
      Lwt_timeout.create 5 (fun () ->
        let delta = Unix.gettimeofday () -. start_time in
        Lwt.wakeup_later r delta)
    in
    Lwt_timeout.start timeout;
    Lwt_timeout.change timeout 1;

    p >|= fun delta ->
    instrument (delta >= 1.9 && delta < 3.1)
      "Lwt_timeout: change after start: %f %f" start_time delta
  end;

  test "change: invalid delay" begin fun () ->
    let timeout = (Lwt_timeout.create 1 ignore) in
    try
      Lwt_timeout.change timeout 0;
      Lwt.return false
    with Invalid_argument _ ->
      Lwt.return true
  end;

  test ~sequential:true "exception in action" begin fun () ->
    let p, r = Lwt.wait () in

    Test.with_async_exception_hook
      (fun exn ->
        match exn with
        | Exit -> Lwt.wakeup_later r true
        | _ -> raise exn)
      (fun () ->
        Lwt_timeout.create 1 (fun () -> raise Exit)
        |> Lwt_timeout.start;

        p)
  end;

  test "set_exn_handler" begin fun () ->
    let p, r = Lwt.wait () in

    Lwt_timeout.set_exn_handler (fun exn ->
      match exn with
      | Exit -> Lwt.wakeup_later r true
      | _ -> raise exn);

    Lwt_timeout.create 1 (fun () -> raise Exit)
    |> Lwt_timeout.start;

    p >|= fun result ->
    Lwt_timeout.set_exn_handler (fun exn ->
      !Lwt.async_exception_hook exn);
    result
  end;

  test "two" begin fun () ->
    let p1, r1 = Lwt.wait () in
    let p2, r2 = Lwt.wait () in

    let start_time = Unix.gettimeofday () in

    Lwt_timeout.create 1 (fun () ->
      let delta = Unix.gettimeofday () -. start_time in
      Lwt.wakeup r1 delta)
    |> Lwt_timeout.start;

    Lwt_timeout.create 2 (fun () ->
      let delta = Unix.gettimeofday () -. start_time in
      Lwt.wakeup r2 delta)
    |> Lwt_timeout.start;

    p1 >>= fun delta1 ->
    p2 >|= fun delta2 ->
    instrument (delta1 >= 1.9 && delta1 < 3. && delta2 >= 2.9 && delta2 < 4.)
      "Lwt_timeout: two: %f %f %f" start_time delta1 delta2
  end;

  test "simultaneous" begin fun () ->
    let p1, r1 = Lwt.wait () in
    let p2, r2 = Lwt.wait () in

    let start_time = Unix.gettimeofday () in

    Lwt_timeout.create 1 (fun () ->
      let delta = Unix.gettimeofday () -. start_time in
      Lwt.wakeup r1 delta)
    |> Lwt_timeout.start;

    Lwt_timeout.create 1 (fun () ->
      let delta = Unix.gettimeofday () -. start_time in
      Lwt.wakeup r2 delta)
    |> Lwt_timeout.start;

    p1 >>= fun delta1 ->
    p2 >|= fun delta2 ->
    instrument (delta1 >= 1. && delta1 < 2.6 && delta2 >= 1. && delta2 < 2.6)
      "Lwt_timeout: simultaneous: %f %f %f" start_time delta1 delta2
  end;

  test "two, first stopped" begin fun () ->
    let p1, r1 = Lwt.wait () in
    let p2, r2 = Lwt.wait () in

    let start_time = Unix.gettimeofday () in

    let timeout1 =
      Lwt_timeout.create 1 (fun () ->
        Lwt.wakeup r1 false)
    in
    Lwt_timeout.start timeout1;

    Lwt_timeout.create 2 (fun () ->
      let delta = Unix.gettimeofday () -. start_time in
      Lwt.wakeup r2 delta)
    |> Lwt_timeout.start;

    Lwt_timeout.stop timeout1;
    Lwt.async (fun () ->
      Lwt_unix.sleep 3. >|= fun () ->
      Lwt.wakeup r1 true);

    p1 >>= fun timeout1_not_fired ->
    p2 >|= fun delta2 ->
    instrument (timeout1_not_fired && delta2 >= 1.5 && delta2 < 3.5)
      "Lwt_timeout: two, first stopped: %b %f %f"
      timeout1_not_fired start_time delta2
  end;
]
