(************************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2016     *)
(*   \VV/  **************************************************************)
(*    //   *      This file is distributed under the terms of the       *)
(*         *       GNU Lesser General Public License Version 2.1        *)
(************************************************************************)

open Pp
open CErrors
open Util
open Names
open Term

let make_dir l = DirPath.make (List.rev_map Id.of_string l)

let find_reference locstr dir s =
  let dp = make_dir dir in
  let sp = Libnames.make_path dp (Id.of_string s) in
  try Nametab.global_of_path sp
  with Not_found ->
    user_err_loc (Loc.ghost, "", str "Library " ++ Libnames.pr_dirpath dp ++
      str " has to be required first.")

let coq_reference locstr dir s = find_reference locstr ("Coq"::dir) s
let coq_constant locstr dir s = Universes.constr_of_global (coq_reference locstr dir s)

let init_constant dir s () = coq_constant "Program" dir s
let init_reference dir s () = coq_reference "Program" dir s

let papp evdref r args = 
  let gr = delayed_force r in
    mkApp (Evarutil.e_new_global evdref gr, args)

let sig_typ = init_reference ["Init"; "Specif"] "sig"
let sig_intro = init_reference ["Init"; "Specif"] "exist"
let sig_proj1 = init_reference ["Init"; "Specif"] "proj1_sig"

let sigT_typ = init_reference ["Init"; "Specif"] "sigT"
let sigT_intro = init_reference ["Init"; "Specif"] "existT"
let sigT_proj1 = init_reference ["Init"; "Specif"] "projT1"
let sigT_proj2 = init_reference ["Init"; "Specif"] "projT2"

let prod_typ = init_reference ["Init"; "Datatypes"] "prod"
let prod_intro = init_reference ["Init"; "Datatypes"] "pair"
let prod_proj1 = init_reference ["Init"; "Datatypes"] "fst"
let prod_proj2 = init_reference ["Init"; "Datatypes"] "snd"

let coq_eq_ind = init_reference ["Init"; "Logic"] "eq"
let coq_eq_refl = init_reference ["Init"; "Logic"] "eq_refl"
let coq_eq_refl_ref = init_reference ["Init"; "Logic"] "eq_refl"
let coq_eq_rect = init_reference ["Init"; "Logic"] "eq_rect"

let coq_JMeq_ind = init_reference ["Logic";"JMeq"] "JMeq"
let coq_JMeq_refl = init_reference ["Logic";"JMeq"] "JMeq_refl"

let coq_not = init_constant ["Init";"Logic"] "not"
let coq_and = init_constant ["Init";"Logic"] "and"

let mk_coq_not x = mkApp (delayed_force coq_not, [| x |])

let unsafe_fold_right f = function
    hd :: tl -> List.fold_right f tl hd
  | [] -> invalid_arg "unsafe_fold_right"

let mk_coq_and l =
  let and_typ = delayed_force coq_and in
    unsafe_fold_right
      (fun c conj ->
	 mkApp (and_typ, [| c ; conj |]))
      l

(* true = transparent by default, false = opaque if possible *)
let proofs_transparency = ref true
let program_cases = ref true
let program_generalized_coercion = ref true

let set_proofs_transparency = (:=) proofs_transparency
let get_proofs_transparency () = !proofs_transparency

let is_program_generalized_coercion () = !program_generalized_coercion
let is_program_cases () = !program_cases

open Goptions

let _ =
  declare_bool_option
  { optsync  = true;
    optdepr  = false;
    optname  = "preferred transparency of Program obligations";
    optkey   = ["Transparent";"Obligations"];
    optread  = get_proofs_transparency;
    optwrite = set_proofs_transparency; }

let _ =
  declare_bool_option
  { optsync  = true;
    optdepr  = false;
    optname  = "program cases";
    optkey   = ["Program";"Cases"];
    optread  = (fun () -> !program_cases);
    optwrite = (:=) program_cases }

let _ =
  declare_bool_option
  { optsync  = true;
    optdepr  = false;
    optname  = "program generalized coercion";
    optkey   = ["Program";"Generalized";"Coercion"];
    optread  = (fun () -> !program_generalized_coercion);
    optwrite = (:=) program_generalized_coercion }