From 482e8b80fa66e328e252567c915f5e96e727f7cf Mon Sep 17 00:00:00 2001
From: Federico Igne <undyamon@disroot.org>
Date: Tue, 23 Jan 2024 18:08:56 +0100
Subject: feat: add simple status bar with timed status message support

---
 bin/main.ml         |  2 +-
 lib/editor.ml       | 85 +++++++++++++++++++++++++++++++++++++++++++++++++----
 lib/editorBuffer.ml | 14 ++++++++-
 lib/terminal.ml     |  9 ++++++
 lib/terminal.mli    | 21 +++++++++++++
 lib/util.ml         |  7 +++++
 6 files changed, 131 insertions(+), 7 deletions(-)

diff --git a/bin/main.ml b/bin/main.ml
index 932c452..e763f70 100644
--- a/bin/main.ml
+++ b/bin/main.ml
@@ -4,5 +4,5 @@ let () =
   let open Editor in
   let cli = Config.parse Sys.argv in
   let editor = Editor.init cli in
-  let rec loop () = Action.(render *> handle_next_command >>= loop) in
+  let rec loop () = Action.(render *> handle_next_command *> tick >>= loop) in
   Action.eval ~editor loop
diff --git a/lib/editor.ml b/lib/editor.ml
index 69dc666..c34d558 100644
--- a/lib/editor.ml
+++ b/lib/editor.ml
@@ -2,7 +2,7 @@ open Base
 module Buffer = EditorBuffer
 open Util
 
-type mode = Normal | Insert
+type mode = Normal | Insert | Control
 type cursor = int * int
 
 type editor = {
@@ -15,6 +15,10 @@ type editor = {
   pending : Key.t Sequence.t;
   i_pending : Command.t Sequence.t;
   n_pending : Command.t Sequence.t;
+  status_size : int;
+  message : string option;
+  message_timestamp : float;
+  message_duration : float;
 }
 
 type t = editor
@@ -30,8 +34,57 @@ let init (c : Config.t) : editor =
     pending = Key.stream;
     i_pending = Command.i_stream;
     n_pending = Command.n_stream;
+    status_size = 2;
+    message = Some "Hello, control line!";
+    message_timestamp = Unix.time ();
+    message_duration = 5.;
   }
 
+let string_of_mode = function
+  | Insert -> " I "
+  | Normal -> " N "
+  | Control -> " C "
+
+let statusbar e =
+  let open Text in
+  (* let open Sequence.Infix in *)
+  let w = e.term.size |> snd in
+  let status =
+    let mode = e.mode |> string_of_mode |> sequence_of_string in
+    let msize = Sequence.length mode
+    and path =
+      Buffer.(
+        e.buffer |> Option.map ~f:kind
+        |> Option.value ~default:No_name
+        |> string_of_kind |> sequence_of_string)
+    and br, bc =
+      Option.(e.buffer |> map ~f:Buffer.size |> value ~default:(0, 0))
+    and cr, cc =
+      Option.(
+        e.buffer
+        |> map ~f:(Buffer.cursor ~rendered:false)
+        |> value ~default:(0, 0))
+    in
+    let perc =
+      match cr with
+      | 0 -> "Top"
+      | n when n = br -> "Bot"
+      | n -> Printf.sprintf "%2d%%" (100 * n / br)
+    in
+    let nav =
+      Printf.sprintf "%d/%d %2d/%2d [%s] " cr br cc bc perc
+      |> sequence_of_string
+    in
+    let nsize = Sequence.length nav in
+    spread ~l:(bold mode) ~lsize:msize ~c:path ~r:(bold nav) ~rsize:nsize
+      ~fill:' ' w
+    |> invert
+  and control =
+    let msg = Option.value ~default:"" e.message |> sequence_of_string in
+    spread ~l:msg ~fill:' ' w
+  in
+  Sequence.(take (of_list [ status; control ]) e.status_size)
+
 type 'a action = t -> 'a * t
 
 module Action = struct
@@ -71,6 +124,8 @@ module Action = struct
   let update_cursor =
     let aux e =
       let dx, dy = e.offset and rs, cs = e.term.size in
+      (* Limit cursor to buffer view *)
+      let rs = rs - e.status_size in
       match Option.map ~f:Buffer.cursor e.buffer with
       | None -> { e with cursor = (1, 1); offset = (0, 0) }
       | Some (cx, cy) ->
@@ -107,22 +162,41 @@ module Action = struct
       let x, y = e.offset
       and ((r, c) as size) = e.term.size
       and fill = Sequence.singleton '~'
+      and status = statusbar e
       and limit =
         Buffer.(if e.rendered then rendered_view else unrendered_view)
       in
-      let view =
+      let ssize = e.status_size in
+      let bufview =
         Option.(
-          e.buffer >>| limit x y r c
+          e.buffer
+          >>| limit x y (r - ssize) c
           |> value ~default:(welcome size)
-          |> Text.extend ~fill r)
+          |> Text.extend ~fill r
+          |> Fn.flip Sequence.take (r - ssize))
       in
-      Terminal.redraw view e.cursor
+      let screen = Sequence.append bufview status in
+      Terminal.redraw screen e.cursor
     in
     get >>| aux
 
   (* TODO: save logic *)
   let quit n = Stdlib.exit n
 
+  (* Statusbar *)
+  let set_message m e =
+    ((), { e with message = m; message_timestamp = Unix.time () })
+
+
+  let tick =
+    let check_message_timestamp e =
+      let now = Unix.time () in
+      let expired = Float.(e.message_timestamp < now - e.message_duration) in
+      if Option.is_some e.message && expired then { e with message = None }
+      else e
+    in
+    get >>| check_message_timestamp >>= put
+
   (* Debug *)
   let get_rendered e = (e.rendered, e)
   let set_rendered r e = ((), { e with rendered = r })
@@ -376,6 +450,7 @@ let handle_next_command m e =
       match Sequence.next e.n_pending with
       | None -> ((), e)
       | Some (h, t) -> handle_normal_command h { e with n_pending = t })
+  | Control -> failwith "unimplemented"
 
 let handle_next_command =
   let open Action in
diff --git a/lib/editorBuffer.ml b/lib/editorBuffer.ml
index e1706dd..c492b8b 100644
--- a/lib/editorBuffer.ml
+++ b/lib/editorBuffer.ml
@@ -21,6 +21,18 @@ let empty =
     rendered = push Sequence.empty empty;
   }
 
+let kind b = b.kind
+
+let string_of_kind = function
+  | No_name -> "[No Name]"
+  | Scratch -> "[Scratch]"
+  | File name -> name
+
+let size e =
+  match e.content with
+  | Error _ -> (0, 0)
+  | Ok z -> (length z, apply_focus_or ~default:0 length z)
+
 let render =
   let open Sequence in
   let tabsize = 8 in
@@ -235,7 +247,7 @@ let unrendered_view x y h w b =
 
 let rendered_view x y h w b =
   let window from len seq = Sequence.(take (drop_eagerly seq from) len) in
-  let cx, _ = cursor b in
+  let cx, _ = cursor ~rendered:false b in
   context ~l:(cx - x) ~r:(x + h - cx) b.rendered
   |> to_seq
   |> Sequence.map ~f:(window y w)
diff --git a/lib/terminal.ml b/lib/terminal.ml
index c8312b6..96103f5 100644
--- a/lib/terminal.ml
+++ b/lib/terminal.ml
@@ -31,6 +31,15 @@ let show_cursor show =
   let cmd = if show then 'h' else 'l' in
   escape cmd ~prefix:"?" ~args:[ 25 ]
 
+(* Incomplete. See https://stackoverflow.com/a/33206814 for a full list
+   of escape codes related to terminal formatting capabilities *)
+let fmt_reset = escape 'm'
+let fmt_bold_on = escape ~args:[ 1 ] 'm'
+let fmt_bold_off = escape ~args:[ 22 ] 'm'
+let fmt_underline = escape ~args:[ 4 ] 'm'
+let fmt_blink = escape ~args:[ 5 ] 'm'
+let fmt_inverted_on = escape ~args:[ 7 ] 'm'
+let fmt_inverted_off = escape ~args:[ 27 ] 'm'
 let input_bytes = Bytes.create 1
 
 let get_char () =
diff --git a/lib/terminal.mli b/lib/terminal.mli
index 0fd11ed..cf8f61d 100644
--- a/lib/terminal.mli
+++ b/lib/terminal.mli
@@ -13,6 +13,27 @@ type state = {
 }
 (** Global state of the terminal window. *)
 
+val fmt_reset : char Sequence.t
+(** Escape sequence: reset text formatting *)
+
+val fmt_bold_on : char Sequence.t
+(** Escape sequence: turn on bold text*)
+
+val fmt_bold_off : char Sequence.t
+(** Escape sequence: turn off bold text*)
+
+val fmt_underline : char Sequence.t
+(** Escape sequence: underlined text*)
+
+val fmt_blink : char Sequence.t
+(** Escape sequence: blinking text*)
+
+val fmt_inverted_on : char Sequence.t
+(** Escape sequence: turn on inverted text*)
+
+val fmt_inverted_off : char Sequence.t
+(** Escape sequence: turn off inverted text*)
+
 val get_char : unit -> char option
 (** Non-blocking request for a keypress.
     Use {!val:Terminal.char_stream} for an infinite sequence of input
diff --git a/lib/util.ml b/lib/util.ml
index 9ad3b59..b86119b 100644
--- a/lib/util.ml
+++ b/lib/util.ml
@@ -24,3 +24,10 @@ let sequence_of_bytes (b : Bytes.t) : char Sequence.t =
     loop 0 ()
   in
   traverse b |> run
+
+(** Turn a string into a sequence.
+
+    @param s the input string.
+    @return a sequence of bytes. *)
+let sequence_of_string (s : string) : char Sequence.t =
+  s |> String.to_list |> Sequence.of_list
-- 
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