(* Build with:
  * corebuild cmd.byte *)


open Core.Std;;

(* With this code, we are trying to
 * Define a common set of arguments to be passed to all sub commands
 * Handle these common arguments all the same way
 * Define sub commands in a common, less verbose way *)

(* The program compiled could be used this way
 * cmd.byte sum 32 + 10 # Display 42
 * cmd.byte settings # Display all the settings
 * But we could use common arguments :
 * cmd.byte sum -c 32 + 10 # Display 42 and a message about color
 * cmd.byte settings # Display all the settings
 * *)

(* Problems:
  * Arguments from other commands are not passed to the functions
  * Several XXX below *)

(* Verbosity *)
let verb = ref 0;;
let color = ref false;;

(* A set of common flags *)
let common =
  let open Command.Spec in
  empty
  +> flag "-v" (optional_with_default 0 int)
    ~doc:"n Set verbosity"
  +> flag "-c" (optional_with_default false bool)
    ~doc:"bool Set color"
  +> flag "--rc" (optional_with_default "" string)
    ~doc:"name Set configuration file"
;;

(* Treating common args *)
let parse_common ~f = fun verbosity col rc ->
  verb := verbosity;
  color := col;

  f ~rc
;;

(* Common way to define subcommands *)
let sub ~f ~summary ~args name =
  let open Command in
  let def =
    basic ~summary:"" Spec.(common +> args) (* XXX Couldn't set set summary with
    the argument ~summary of sub function. Error is
      This expression has type t -> bytes
      but an expression was expected of type bytes*)
      (parse_common ~f)
  in
    ( name, def )
;;

(* Two sub commands *)

(* Display the sum of the arguments *)
let sum =
  sub
    ~f:(fun ~rc _ () -> (* XXX Strange arguments passed here *)
      (* We would like to get the numbers passed in arguments ("first number"
       * and "second number" below) *)
      ();
      (* Some code to use common arguments *)
      if !color then printf "Colored\n" else print_endline rc)
    ~args:(Command.Spec.(
      empty
      +> anon ("first number" %: int)
      +> anon ("second number" %: int)
      ))
    ~summary:"Sum"
    "sum"
;;

(* Print some settings and a number passed to the program *)
let settings =
  sub
    ~f:(fun ~rc _ () ->
      printf "Settings\n";
      printf "Rc: %s" rc;
      printf "Color: %b" !color)
    ~args:(let open Command.Spec in
      empty
      )
    ~summary:"Display settings"
    "settings"
;;

let () =
  let open Command in
  group ~summary:"A program to test" [ sum ; settings ]
  |> run ~version:"" ~build_info:"" ~argv:[]
;;