type t = { vals : int list; opts : Options.t }

let default = { vals = []; opts = Options.default }

let plot v c = { c with vals = v }

let with_options v c = { c with opts = v }

let pp formatter { vals : int list; opts : Options.t } =
  let open Utils in
  let height = opts.height in
  let min_val = list_min vals in
  let max_val = list_max vals in
  let range = max_val - min_val in
  let scale v = (v - min_val) * height / range in
  let new_vals = List.map scale vals in
  let rec pad left right s =
    if left = 0 then s :: repeat right space
    else space :: pad (left - 1) right s
  in
  let new_vals' = zip new_vals (List.tl new_vals) in
  let make_marker prefix left right s =
    prefix
    ::
    (if left = 0 then s :: repeat right space
    else space :: pad (left - 1) right s)
  in
  let make_connector s e =
    match Stdlib.compare s e with
    | 0 -> make_marker axis_spc s (height - s) "-"
    | x ->
        let ltr_chr, rtl_chr =
          match x with 1 -> ("└", "┐") | _ -> ("┘", "┌")
        in
        let st, en = Stdlib.(min s e, max s e) in
        let l = en - st |> saturating_sub 1 in
        let left, right = (repeat st space, repeat (height - l - st) space) in
        List.flatten
          [
            [ axis_spc ]; left; [ ltr_chr ]; repeat l "│"; [ rtl_chr ]; right;
          ]
  in
  let m = Format.asprintf "%a" Marker.pp opts.marker in
  let rec make_graph = function
    | [] -> []
    | [ (s, e) ] ->
        [
          make_marker axis s (height - s) m;
          make_connector s e;
          make_marker axis e (height - e) m;
        ]
    | (s, e) :: tl ->
        make_marker axis s (height - s) m :: make_connector s e :: make_graph tl
  in
  make_graph new_vals' |> rot_left
  |> List.map (String.concat "")
  |> String.concat "\n"
  |> Format.fprintf formatter "%s"