open Inshellah.Parser
open Inshellah.Manpage
open Inshellah.Nushell

let usage () =
  Printf.eprintf {|inshellah — generate nushell completions from manpages and --help output

Usage:
  inshellah manpage FILE          Parse a manpage (.1, .1.gz) and emit nushell extern
  inshellah manpage-dir DIR       Batch-process all manpages under DIR/man1/
  inshellah help CMD [ARGS...]    Run CMD ARGS --help, parse output, emit nushell extern
  inshellah parse-help CMD        Read --help text from stdin, emit nushell extern for CMD
  inshellah demo                  Run built-in demo

|};
  exit 1

(* Extract command name from a manpage filename *)
let cmd_name_of_manpage path =
  let base = Filename.basename path in
  (* strip .gz if present *)
  let base =
    if Filename.check_suffix base ".gz" then Filename.chop_suffix base ".gz"
    else base
  in
  (* strip .N section suffix *)
  try Filename.chop_extension base
  with Invalid_argument _ -> base

let cmd_manpage file =
  let cmd = cmd_name_of_manpage file in
  let entries = parse_manpage_file file in
  if entries <> [] then
    print_string (generate_extern_from_entries cmd entries)

let cmd_manpage_dir dir =
  (* Walk man1/ through man9/ looking for manpages *)
  for section = 1 to 9 do
    let subdir = Filename.concat dir (Printf.sprintf "man%d" section) in
    if Sys.file_exists subdir && Sys.is_directory subdir then begin
      let files = Sys.readdir subdir in
      Array.sort String.compare files;
      Array.iter (fun file ->
        let path = Filename.concat subdir file in
        try cmd_manpage path
        with _ -> ()  (* skip unparseable manpages *)
      ) files
    end
  done

let cmd_help args =
  match args with
  | [] -> Printf.eprintf "error: help mode requires a command name\n"; exit 1
  | cmd :: rest ->
    let full_cmd =
      String.concat " " (List.map Filename.quote (cmd :: rest @ ["--help"]))
    in
    let ic = Unix.open_process_in (full_cmd ^ " 2>&1") in
    let buf = Buffer.create 4096 in
    (try while true do
       let line = input_line ic in
       Buffer.add_string buf line;
       Buffer.add_char buf '\n'
     done with End_of_file -> ());
    let _ = Unix.close_process_in ic in
    let text = Buffer.contents buf in
    let cmd_name = Filename.basename cmd in
    (match parse_help text with
     | Ok r -> print_string (generate_extern cmd_name r)
     | Error msg -> Printf.eprintf "parse error for %s: %s\n" cmd_name msg; exit 1)

let cmd_parse_help cmd =
  let buf = Buffer.create 4096 in
  (try while true do
     let line = input_line stdin in
     Buffer.add_string buf line;
     Buffer.add_char buf '\n'
   done with End_of_file -> ());
  let text = Buffer.contents buf in
  (match parse_help text with
   | Ok r -> print_string (generate_extern cmd r)
   | Error msg -> Printf.eprintf "parse error for %s: %s\n" cmd msg; exit 1)

let cmd_demo () =
  let ls_help =
    {|Usage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).

  -a, --all                  do not ignore entries starting with .
  -A, --almost-all           do not list implied . and ..
      --block-size=SIZE      with -l, scale sizes by SIZE when printing them;
                               e.g., '--block-size=M'; see SIZE format below
      --color[=WHEN]         color the output WHEN
  -h, --human-readable       with -l and -s, print sizes like 1K 234M 2G etc.
      --help                 display this help and exit
      --version              output version information and exit
|}
  in
  Printf.printf "# Generated by: inshellah demo\n\n";
  (match parse_help ls_help with
   | Ok r -> print_string (generate_extern "ls" r)
   | Error msg -> Printf.eprintf "parse error: %s\n" msg)

let () =
  let args = Array.to_list Sys.argv |> List.tl in
  match args with
  | ["manpage"; file] -> cmd_manpage file
  | ["manpage-dir"; dir] -> cmd_manpage_dir dir
  | "help" :: rest -> cmd_help rest
  | ["parse-help"; cmd] -> cmd_parse_help cmd
  | ["demo"] -> cmd_demo ()
  | _ -> usage ()