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

:< sm'_operators

:= new_samples () : mut (list i32) = mut []

:= sample (s : mut (list i32)) (value : i32) : () = s <- value :: *s

:= in_order (s : mut (list i32)) : list i32 = listm::rev *s

:= sample_count (s : mut (list i32)) : i32 = listm::length *s

:= sample_total (s : mut (list i32)) : i32 = listm::fold (\ total value => total + value) 0i32 *s

:= sample_max (s : mut (list i32)) : i32 = listm::fold (\ most value => ? value > most ?> value |: most) 0i32 *s

:~ ^ insert_sorted (value : i32) (xs : list i32) : list i32 =
    ?= xs ?|
    | [] => [ value ]
    | head :: rest => ? value <= head ?> value :: xs |: head :: insert_sorted value rest

:= sorted (xs : list i32) : list i32 = listm::fold (\ acc value => insert_sorted value acc) [] xs

:~ ^ nth (index : i32) (xs : list i32) : i32 =
    ?= xs ?|
    | [] => 0i32
    | head :: rest => ? index = 0i32 ?> head |: nth (index - 1i32) rest

:= median_of (ordered : list i32) (n : i32) : i32 = nth ((n + 1i32) / 2i32 - 1i32) ordered

:= sample_median (s : mut (list i32)) : i32 =
    := n = sample_count s
    ? n = 0i32 ?> 0i32 |: median_of (sorted *s) n

:= samples_joined (s : mut (list i32)) : string = in_order s |> listm::map (\ v => "" ++#? v) |> sm'::concat_list ","

///> lua
///> c
:# samples_count_total_max_and_median =
    := s = new_samples ()
    sample s 7i32
    sample s 3i32
    sample s 9i32
    sample s 1i32
    (sample_count s, sample_total s, sample_max s, sample_median s) |> _assert_eq (4i32, 20i32, 9i32, 3i32)

///> lua
:# samples_join_in_insertion_order =
    := s = new_samples ()
    sample s 7i32
    sample s 3i32
    samples_joined s |> _assert_eq "7,3"

///> lua
///> c
:# empty_samples_report_zero =
    := s = new_samples ()
    (sample_count s, sample_total s, sample_max s, sample_median s) |> _assert_eq (0i32, 0i32, 0i32, 0i32)

:== labeled = string * list i32

:= new_labeled_samples () : mut (list labeled) = mut []

:= label_of (entry : labeled) : string =
    := label, _ = entry
    label

:= added_to (value : i32) (entry : labeled) : labeled =
    := label, values = entry
    label, value :: values

:~ ^ with_labeled (label : string) (value : i32) (xs : list labeled) : list labeled =
    ?= xs ?|
    | [] => [ (label, [ value ]) ]
    | entry :: rest =>
        ? label_of entry = label ?> added_to value entry :: rest |: entry :: with_labeled label value rest

:= labeled_sample (s : mut (list labeled)) (label : string) (value : i32) : () =
    s <- with_labeled label value *s

:~ ^ insert_by_label (entry : labeled) (xs : list labeled) : list labeled =
    ?= xs ?|
    | [] => [ entry ]
    | head :: rest =>
        ? lt_is (comp (label_of entry) (label_of head)) ?> entry :: xs |: head :: insert_by_label entry rest

:= range_text (ordered : list i32) (n : i32) : string =
    " min " ++#? nth 0i32 ordered ++# " max " ++#? nth (n - 1i32) ordered

:= label_line (entry : labeled) : string =
    := label, values = entry
    := ordered = sorted values
    := n = listm::length values
    label
    ++# " n="
    ++#? n
    ++# " median "
    ++#? median_of ordered n
    ++# range_text ordered n

:= labeled_summary (s : mut (list labeled)) : string =
    listm::fold (\ acc entry => insert_by_label entry acc) [] *s |> listm::map label_line |> sm'::concat_list "; "

:== stamped = i32 * i32 * string

:= new_stamps () : mut (list stamped) = mut []

:~ ^ stamp_of (key : i32) (stamps : list stamped) : i32 * string =
    ?= stamps ?|
    | [] => -1i32, ""
    | (known, at, kind) :: rest => ? known = key ?> at, kind |: stamp_of key rest

:~ ^ restamped (key : i32) (at : i32) (kind : string) (stamps : list stamped) : list stamped =
    ?= stamps ?|
    | [] => [ (key, at, kind) ]
    | (known, a, k) :: rest =>
        ? known = key ?> (key, at, kind) :: rest |: (known, a, k) :: restamped key at kind rest

:= stamp (s : mut (list stamped)) (key : i32) (at : i32) (kind : string) : () =
    s <- restamped key at kind *s

:= last_stamp (s : mut (list stamped)) (key : i32) : i32 * string = stamp_of key *s

:= ab_summary_expected () : string = "a n=1 median 2 min 2 max 2; b n=2 median 1 min 1 max 3"

///> lua
///> c
:# labeled_samples_summarize_each_label_in_order =
    := s = new_labeled_samples ()
    labeled_sample s "b" 3i32
    labeled_sample s "a" 2i32
    labeled_sample s "b" 1i32
    labeled_summary s |> _assert_eq (ab_summary_expected ())

///> lua
///> c
:# labels_sort_a_prefix_before_its_extension =
    := s = new_labeled_samples ()
    labeled_sample s "kd-chasing" 5i32
    labeled_sample s "kd" 4i32
    labeled_summary s |> _assert_eq "kd n=1 median 4 min 4 max 4; kd-chasing n=1 median 5 min 5 max 5"

:== stamp_seen = i32 * string

:= stamps_expected () : stamp_seen * stamp_seen * stamp_seen * stamp_seen =
    (-1, ""), (130, "knight-straight"), (50, "diagonal"), (-1, "")

:= stamp_three_moves (s : mut (list stamped)) : () =
    stamp s 7i32 100i32 "straight"
    stamp s 9i32 50i32 "diagonal"
    stamp s 7i32 130i32 "knight-straight"

///> lua
///> c
:# stamps_remember_the_last_time_and_kind_per_key =
    := s = new_stamps ()
    := before = last_stamp s 7i32
    stamp_three_moves s
    (before, last_stamp s 7i32, last_stamp s 9i32, last_stamp s 8i32) |> _assert_eq (stamps_expected ())