(************************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2010     *)
(*   \VV/  **************************************************************)
(*    //   *      This file is distributed under the terms of the       *)
(*         *       GNU Lesser General Public License Version 2.1        *)
(************************************************************************)

open Pp
open Util
open Names
open Nameops
open Term
open Mod_subst

(*s Global reference is a kernel side type for all references together *)
type global_reference =
  | VarRef of variable
  | ConstRef of constant
  | IndRef of inductive
  | ConstructRef of constructor

let isVarRef = function VarRef _ -> true | _ -> false
let isConstRef = function ConstRef _ -> true | _ -> false
let isIndRef = function IndRef _ -> true | _ -> false
let isConstructRef = function ConstructRef _ -> true | _ -> false

let eq_gr gr1 gr2 =
  match gr1,gr2 with 
    | ConstRef con1, ConstRef con2 -> eq_constant con1 con2
    | IndRef kn1,IndRef kn2 -> eq_ind kn1 kn2
    | ConstructRef kn1,ConstructRef kn2 -> eq_constructor kn1 kn2
    | _,_ -> gr1=gr2

let destVarRef = function VarRef ind -> ind | _ -> failwith "destVarRef"
let destConstRef = function ConstRef ind -> ind | _ -> failwith "destConstRef"
let destIndRef = function IndRef ind -> ind | _ -> failwith "destIndRef"
let destConstructRef = function ConstructRef ind -> ind | _ -> failwith "destConstructRef"

let subst_constructor subst ((kn,i),j as ref) =
  let kn' = subst_ind subst kn in
    if kn==kn' then ref, mkConstruct ref
    else ((kn',i),j), mkConstruct ((kn',i),j)

let subst_global subst ref = match ref with
  | VarRef var -> ref, mkVar var
  | ConstRef kn ->
     let kn',t = subst_con subst kn in
      if kn==kn' then ref, mkConst kn else ConstRef kn', t
  | IndRef (kn,i) ->
      let kn' = subst_ind subst kn in
      if kn==kn' then ref, mkInd (kn,i) else IndRef(kn',i), mkInd (kn',i)
  | ConstructRef ((kn,i),j as c) ->
      let c',t = subst_constructor subst c in
	if c'==c then ref,t else ConstructRef c', t

let canonical_gr = function
  | ConstRef con -> ConstRef(constant_of_kn(canonical_con con))
  | IndRef (kn,i) -> IndRef(mind_of_kn(canonical_mind kn),i)
  | ConstructRef ((kn,i),j )-> ConstructRef((mind_of_kn(canonical_mind kn),i),j)
  | VarRef id -> VarRef id

let global_of_constr c = match kind_of_term c with
  | Const sp -> ConstRef sp
  | Ind ind_sp -> IndRef ind_sp
  | Construct cstr_cp -> ConstructRef cstr_cp
  | Var id -> VarRef id
  |  _ -> raise Not_found

let constr_of_global = function
  | VarRef id -> mkVar id
  | ConstRef sp -> mkConst sp
  | ConstructRef sp -> mkConstruct sp
  | IndRef sp -> mkInd sp

let constr_of_reference = constr_of_global
let reference_of_constr = global_of_constr

let global_ord_gen fc fmi x y =
  let ind_ord (indx,ix) (indy,iy) =
    let c = Pervasives.compare ix iy in
    if c = 0 then kn_ord (fmi indx) (fmi indy) else c
  in
  match x, y with
    | ConstRef cx, ConstRef cy -> kn_ord (fc cx) (fc cy)
    | IndRef indx, IndRef indy -> ind_ord indx indy
    | ConstructRef (indx,jx), ConstructRef (indy,jy) ->
      let c = Pervasives.compare jx jy in
      if c = 0 then ind_ord indx indy else c
    | _, _ -> Pervasives.compare x y

let global_ord_can = global_ord_gen canonical_con canonical_mind
let global_ord_user = global_ord_gen user_con user_mind

(* By default, [global_reference] are ordered on their canonical part *)

module RefOrdered = struct
  type t = global_reference
  let compare = global_ord_can
end

module RefOrdered_env = struct
  type t = global_reference
  let compare = global_ord_user
end

module Refset = Set.Make(RefOrdered)
module Refmap = Map.Make(RefOrdered)

(* Extended global references *)

type syndef_name = kernel_name

type extended_global_reference =
  | TrueGlobal of global_reference
  | SynDef of syndef_name

(* We order [extended_global_reference] via their user part
   (cf. pretty printer) *)

module ExtRefOrdered = struct
  type t = extended_global_reference
  let compare x y =
    match x, y with
      | TrueGlobal rx, TrueGlobal ry -> global_ord_user rx ry
      | SynDef knx, SynDef kny -> kn_ord knx kny
      | _, _ -> Pervasives.compare x y
end

(**********************************************)

let pr_dirpath sl = (str (string_of_dirpath sl))

(*s Operations on dirpaths *)

(* Pop the last n module idents *)
let pop_dirpath_n n dir =
  make_dirpath (list_skipn n (repr_dirpath dir))

let pop_dirpath p = match repr_dirpath p with
  | [] -> anomaly "dirpath_prefix: empty dirpath"
  | _::l -> make_dirpath l

let is_dirpath_prefix_of d1 d2 =
  list_prefix_of (List.rev (repr_dirpath d1)) (List.rev (repr_dirpath d2))

let chop_dirpath n d =
  let d1,d2 = list_chop n (List.rev (repr_dirpath d)) in
    make_dirpath (List.rev d1), make_dirpath (List.rev d2)

let drop_dirpath_prefix d1 d2 =
  let d = Util.list_drop_prefix (List.rev (repr_dirpath d1)) (List.rev (repr_dirpath d2)) in
    make_dirpath (List.rev d)

let append_dirpath d1 d2 = make_dirpath (repr_dirpath d2 @ repr_dirpath d1)

(* To know how qualified a name should be to be understood in the current env*)
let add_dirpath_prefix id d = make_dirpath (repr_dirpath d @ [id])

let split_dirpath d =
  let l = repr_dirpath d in (make_dirpath (List.tl l), List.hd l)

let add_dirpath_suffix p id = make_dirpath (id :: repr_dirpath p)

(* parsing *)
let parse_dir s =
  let len = String.length s in
  let rec decoupe_dirs dirs n =
    if n = len && n > 0 then error (s ^ " is an invalid path.");
    if n >= len then dirs else
    let pos =
      try
	String.index_from s n '.'
      with Not_found -> len
    in
    if pos = n then error (s ^ " is an invalid path.");
    let dir = String.sub s n (pos-n) in
    decoupe_dirs ((id_of_string dir)::dirs) (pos+1)
  in
    decoupe_dirs [] 0

let dirpath_of_string s =
  make_dirpath (if s = "" then [] else parse_dir s)

let string_of_dirpath = Names.string_of_dirpath


module Dirset = Set.Make(struct type t = dir_path let compare = compare end)
module Dirmap = Map.Make(struct type t = dir_path let compare = compare end)

(*s Section paths are absolute names *)

type full_path = {
  dirpath : dir_path ;
  basename : identifier }

let make_path pa id = { dirpath = pa; basename = id }

let repr_path { dirpath = pa; basename = id } = (pa,id)

(* parsing and printing of section paths *)
let string_of_path sp =
  let (sl,id) = repr_path sp in
  if repr_dirpath sl = [] then string_of_id id
  else (string_of_dirpath sl) ^ "." ^ (string_of_id id)

let sp_ord sp1 sp2 =
  let (p1,id1) = repr_path sp1
  and (p2,id2) = repr_path sp2 in
  let p_bit = compare p1 p2 in
  if p_bit = 0 then id_ord id1 id2 else p_bit

module SpOrdered =
  struct
    type t = full_path
    let compare = sp_ord
  end

module Spmap = Map.Make(SpOrdered)

let dirpath sp = let (p,_) = repr_path sp in p
let basename sp = let (_,id) = repr_path sp in id

let path_of_string s =
  try
    let dir, id = split_dirpath (dirpath_of_string s) in
    make_path dir id
  with
    | Invalid_argument _ -> invalid_arg "path_of_string"

let pr_path sp = str (string_of_path sp)

let restrict_path n sp =
  let dir, s = repr_path sp in
  let dir' = list_firstn n (repr_dirpath dir) in
  make_path (make_dirpath dir') s

let encode_mind dir id = make_mind (MPfile dir) empty_dirpath (label_of_id id)

let encode_con dir id = make_con (MPfile dir) empty_dirpath (label_of_id id)

let decode_mind kn =
  let rec dir_of_mp = function
    | MPfile dir -> repr_dirpath dir
    | MPbound mbid -> 
	let _,_,dp = repr_mbid mbid in
	let id = id_of_mbid mbid in
	  id::(repr_dirpath dp)
    | MPdot(mp,l) -> (id_of_label l)::(dir_of_mp mp)
  in
  let mp,sec_dir,l = repr_mind kn in
    if (repr_dirpath sec_dir) = [] then
     (make_dirpath (dir_of_mp mp)),id_of_label l
    else
      anomaly "Section part should be empty!"

let decode_con kn =
  let mp,sec_dir,l = repr_con kn in
    match mp,(repr_dirpath sec_dir) with
	MPfile dir,[] -> (dir,id_of_label l)
      | _ , [] -> anomaly "MPfile expected!"
      | _ -> anomaly "Section part should be empty!"

(*s qualified names *)
type qualid = full_path

let make_qualid = make_path
let repr_qualid = repr_path

let string_of_qualid = string_of_path
let pr_qualid = pr_path

let qualid_of_string = path_of_string

let qualid_of_path sp = sp
let qualid_of_ident id = make_qualid empty_dirpath id
let qualid_of_dirpath dir =
  let (l,a) = split_dirpath dir in
  make_qualid l a

type object_name = full_path * kernel_name

type object_prefix = dir_path * (module_path * dir_path)

let make_oname (dirpath,(mp,dir)) id =
  make_path dirpath id, make_kn mp dir (label_of_id id)

(* to this type are mapped dir_path's in the nametab *)
type global_dir_reference =
  | DirOpenModule of object_prefix
  | DirOpenModtype of object_prefix
  | DirOpenSection of object_prefix
  | DirModule of object_prefix
  | DirClosedSection of dir_path
      (* this won't last long I hope! *)

(*  | ModRef mp ->
      let mp' = subst_modpath subst mp in if mp==mp' then ref else
          ModRef mp'
  | ModTypeRef kn ->
      let kn' = subst_kernel_name subst kn in if kn==kn' then ref else
          ModTypeRef kn'
*)

type reference =
  | Qualid of qualid located
  | Ident of identifier located

let qualid_of_reference = function
  | Qualid (loc,qid) -> loc, qid
  | Ident (loc,id) -> loc, qualid_of_ident id

let string_of_reference = function
  | Qualid (loc,qid) -> string_of_qualid qid
  | Ident (loc,id) -> string_of_id id

let pr_reference = function
  | Qualid (_,qid) -> pr_qualid qid
  | Ident (_,id) -> pr_id id

let loc_of_reference = function
  | Qualid (loc,qid) -> loc
  | Ident (loc,id) -> loc

(* popping one level of section in global names *)

let pop_con con =
  let (mp,dir,l) = repr_con con in
  Names.make_con mp (pop_dirpath dir) l

let pop_kn kn =
  let (mp,dir,l) = repr_mind kn in
  Names.make_mind mp (pop_dirpath dir) l

let pop_global_reference = function
  | ConstRef con -> ConstRef (pop_con con)
  | IndRef (kn,i) -> IndRef (pop_kn kn,i)
  | ConstructRef ((kn,i),j) -> ConstructRef ((pop_kn kn,i),j)
  | VarRef id -> anomaly "VarRef not poppable"

(* Deprecated synonyms *)

let make_short_qualid = qualid_of_ident
let qualid_of_sp = qualid_of_path