///- --package .
:# path static =
    :< testing

:< sm'_operators
:= watch_ms () : i32 = 30000
:= sample_ms () : i32 = 50

:= followed (last : option client::spot) (at : client::spot) (steps : i32) : bool * i32 =
    ?= last ?|
    | Some l =>
        := moved = at::x <> l::x || at::y <> l::y
        moved, (? moved ?> steps + 1 |: steps)
    | None => !+, steps

:= step_line (elapsed : i32) (from : string) (distance : i32) (steps : i32) : string =
    "path t=" ++#? elapsed ++# " ms monster at " ++# from ++# " distance " ++#? distance ++# " step " ++#? steps

:= arrived_line (elapsed : i32) (steps : i32) (knight : string) : string =
    "arrived at " ++#? elapsed ++# " ms after " ++#? steps ++# " steps, knight at " ++# knight

:= not_arrived_line (elapsed : i32) (steps : i32) : string =
    "not arrived after " ++#? elapsed ++# " ms, " ++#? steps ++# " steps"

:== trail = { last : option client::spot; steps : i32 }

:= fresh_trail () : trail = { last = None; steps = 0 }

:= seen_spot (people : client::crowd) (seen : probe::nearest) : client::spot =
    client::creature_spot (client::member people seen::index)

:= step_noted (elapsed : i32) (at : client::spot) (distance : i32) (steps : i32) : () =
    probe::note (step_line elapsed (probe::described at) distance steps)

:= trail_moved (t : trail) (at : client::spot) (dt : i32) (distance : i32) : trail =
    := moved, steps = followed t::last at t::steps
    ? moved ?> step_noted dt at distance steps
    { last = (? moved ?> Some at |: t::last); steps = steps }

:= seen_trail (t : trail) (people : client::crowd) (seen : probe::spotted) (elapsed : i32) : bool * trail =
    ?= seen ?|
    | Some n => n::distance <= 1, trail_moved t (seen_spot people n) elapsed n::distance
    | None => !-, t

:= sample_at (here : client::spot) (t : trail) (elapsed : i32) : bool * trail =
    := people = client::spectators here
    seen_trail t people (probe::nearest_monster here people) elapsed

:= finished_arrived (done : mut i32) (elapsed : i32) (steps : i32) (here : client::spot) : bool =
    probe::note (arrived_line elapsed steps (probe::described here))
    probe::finish_once_without_parity done "arrived"
    !+

:= finished_not_arrived (done : mut i32) (elapsed : i32) (steps : i32) : bool =
    probe::note (not_arrived_line elapsed steps)
    probe::finish_once_without_parity done "not arrived"
    !+

:= ended (done : mut i32) (elapsed : i32) (here : client::spot) (arrived : bool) (steps : i32) : bool =
    ? arrived ?> finished_arrived done elapsed steps here
    |? elapsed > watch_ms () ?> finished_not_arrived done elapsed steps
    |: !-

:= path_tick (done : mut i32) (elapsed : i32) (t : trail) (again : trail -> ()) : () =
    := here = client::player_spot ()
    := arrived, t = sample_at here t elapsed
    ? ended done elapsed here arrived t::steps = !- ?> client::after (sample_ms ()) \ () => again t

:= watch (done : mut i32) (started_at : i32) : () =
    :~ ^ go (t : trail) : () =
        ? client::player_present () = !- ?> probe::finish_once_without_parity done "offline"
        |: path_tick done (client::now_ms () - started_at) t go
    go (fresh_trail ())

///> lua
///> c
:# a_first_sighting_is_not_a_step =
    followed None { x = 1940; y = 1352; z = 7 } 0 |> _assert_eq (!+, 0i32)

///> lua
///> c
:# standing_still_keeps_the_step_count =
    followed (Some { x = 1940; y = 1352; z = 7 }) { x = 1940; y = 1352; z = 7 } 3 |> _assert_eq (!-, 3i32)

///> lua
///> c
:# a_move_after_a_sighting_counts_a_step =
    followed (Some { x = 1940; y = 1352; z = 7 }) { x = 1939; y = 1352; z = 7 } 3 |> _assert_eq (!+, 4i32)

///> lua
///> c
:# the_step_line_keeps_the_probe_wording =
    step_line 850 "1939,1352,7" 3 4 |> _assert_eq "path t=850 ms monster at 1939,1352,7 distance 3 step 4"

///> lua
///> c
:# the_end_lines_keep_the_probe_wording =
    (arrived_line 2400 6 "1936,1349,7", not_arrived_line 30050 9)
    |> _assert_eq ("arrived at 2400 ms after 6 steps, knight at 1936,1349,7", "not arrived after 30050 ms, 9 steps")

:= server_text_noted (mode : string) (text : string) : () = probe::note ("server text [" ++# mode ++# "]: " ++# text)

:= path_started (done : mut i32) : () =
    := name, at = client::player_name (), probe::described (client::player_spot ())
    probe::note ("in game as " ++# name ++# " at " ++# at ++# " (path check, standing, no attack)")
    watch done (client::now_ms ())

:= timed_out (done : mut i32) : () = probe::finish_once_without_parity done "timeout"

///> _
:= main () =
    := done = mut 0
    := ready () = client::after 1500 \ () => path_started done
    client::disable_client_bot (probe::bot_profile ())
    probe::started_as (probe::knight ()) server_text_noted ready 60000 \ () => timed_out done
    0i32