(************************************************************************)
(*         *   The Coq Proof Assistant / The Coq Development Team       *)
(*  v      *   INRIA, CNRS and contributors - Copyright 1999-2018       *)
(* <O___,, *       (see CREDITS file for the list of authors)           *)
(*   \VV/  **************************************************************)
(*    //   *    This file is distributed under the terms of the         *)
(*         *     GNU Lesser General Public License Version 2.1          *)
(*         *     (see LICENSE file for the text of the license)         *)
(************************************************************************)

open Printf
open Cdglobals

type loc = int

type entry_type =
  | Library
  | Module
  | Definition
  | Inductive
  | Constructor
  | Lemma
  | Record
  | Projection
  | Instance
  | Class
  | Method
  | Variable
  | Axiom
  | TacticDefinition
  | Abbreviation
  | Notation
  | Section

type index_entry =
  | Def of string * entry_type
  | Ref of coq_module * string * entry_type

let current_library = ref ""
  (** refers to the file being parsed *)

(** [deftable] stores only definitions and is used to build the index *)
let deftable = Hashtbl.create 97

(** [byidtable] is used to interpolate idents inside comments, which are not
    globalized otherwise. *)
let byidtable = Hashtbl.create 97

(** [reftable] stores references and definitions *)
let reftable = Hashtbl.create 97

let full_ident sp id =
  if sp <> "<>" then
    if id <> "<>" then
      sp ^ "." ^ id
    else sp
  else if id <> "<>"
  then id
  else ""

let add_def loc1 loc2 ty sp id =
  let fullid = full_ident sp id in
  let def = Def (fullid, ty) in
  for loc = loc1 to loc2 do
    Hashtbl.add reftable (!current_library, loc) def
  done;
  Hashtbl.add deftable !current_library (fullid, ty);
  Hashtbl.add byidtable id (!current_library, fullid, ty)

let add_ref m loc m' sp id ty =
  let fullid = full_ident sp id in
  if Hashtbl.mem reftable (m, loc) then ()
  else Hashtbl.add reftable (m, loc) (Ref (m', fullid, ty));
  let idx = if id = "<>" then m' else id in
    if Hashtbl.mem byidtable idx then ()
    else Hashtbl.add byidtable idx (m', fullid, ty)

let find m l = Hashtbl.find reftable (m, l)

let find_string s = let (m,s,t) = Hashtbl.find byidtable s in Ref (m,s,t)

(* Coq modules *)

let split_sp s =
  try
    let i = String.rindex s '.' in
      String.sub s 0 i, String.sub s (i + 1) (String.length s - i - 1)
  with
      Not_found -> "", s

let modules = Hashtbl.create 97
let local_modules = Hashtbl.create 97

let add_module m =
  let _,id = split_sp m in
  Hashtbl.add modules id m;
  Hashtbl.add local_modules m ()

type module_kind = Local | External of string | Unknown

let external_libraries = ref []

let add_external_library logicalpath url =
  external_libraries := (logicalpath,url) :: !external_libraries

let find_external_library logicalpath =
  let rec aux = function
    | [] -> raise Not_found
    | (l,u)::rest ->
        if String.length logicalpath > String.length l &&
          String.sub logicalpath 0 (String.length l + 1) = l ^"."
        then u
        else aux rest
  in aux !external_libraries

let init_coqlib_library () = add_external_library "Coq" !coqlib

let find_module m =
  if Hashtbl.mem local_modules m then
    Local
  else
    try External (find_external_library m ^ "/" ^ m)
    with Not_found -> Unknown


(* Building indexes *)

type 'a index = {
  idx_name : string;
  idx_entries : (char * (string * 'a) list) list;
  idx_size : int }

let map f i =
  { i with idx_entries =
      List.map
	(fun (c,l) -> (c, List.map (fun (s,x) -> (s,f s x)) l))
	i.idx_entries }

let compare_entries (s1,_) (s2,_) = Alpha.compare_string s1 s2

let sort_entries el =
  let t = Hashtbl.create 97 in
  List.iter
    (fun c -> Hashtbl.add t c [])
    ['A'; 'B'; 'C'; 'D'; 'E'; 'F'; 'G'; 'H'; 'I'; 'J'; 'K'; 'L'; 'M'; 'N';
     'O'; 'P'; 'Q'; 'R'; 'S'; 'T'; 'U'; 'V'; 'W'; 'X'; 'Y'; 'Z'; '_'; '*'];
  List.iter
    (fun ((s,_) as e) ->
      let c = Alpha.norm_char s.[0] in
      let c,l =
	try c,Hashtbl.find t c with Not_found -> '*',Hashtbl.find t '*' in
      Hashtbl.replace t c (e :: l))
    el;
  let res = ref [] in
  Hashtbl.iter (fun c l -> res := (c, List.sort compare_entries l) :: !res) t;
  List.sort (fun (c1,_) (c2,_) -> Alpha.compare_char c1 c2) !res

let display_letter c = if c = '*' then "other" else String.make 1 c

[@@@ocaml.warning "-3"]       (* String.lowercase_ascii since 4.03.0 GPR#124 *)
let lowercase = String.lowercase
[@@@ocaml.warning "+3"]

let type_name = function
  | Library ->
      let ln = !lib_name in
        if ln <> "" then lowercase ln else "library"
  | Module -> "module"
  | Definition -> "definition"
  | Inductive -> "inductive"
  | Constructor -> "constructor"
  | Lemma -> "lemma"
  | Record -> "record"
  | Projection -> "projection"
  | Instance -> "instance"
  | Class -> "class"
  | Method -> "method"
  | Variable -> "variable"
  | Axiom -> "axiom"
  | TacticDefinition -> "tactic"
  | Abbreviation -> "abbreviation"
  | Notation -> "notation"
  | Section -> "section"

let prepare_entry s = function
  | Notation ->
      (* We decode the encoding done in Dumpglob.cook_notation of coqtop *)
      (* Encoded notations have the form section:entry:sc:x_'++'_x       *)
      (* where:                                                          *)
      (* - the section, if any, ends with a "."                          *)
      (* - the scope can be empty                                        *)
      (* - tokens are separated with "_"                                 *)
      (* - non-terminal symbols are conventionally represented by "x"    *)
      (* - terminals are enclosed within simple quotes                   *)
      (* - existing simple quotes (that necessarily are parts of         *)
      (*   terminals) are doubled                                        *)
      (*   (as a consequence, when a terminal contains "_" or "x", these *)
      (*   necessarily appear enclosed within non-doubled simple quotes) *)
      (* - non-printable characters < 32 are left encoded so that they   *)
      (*   are human-readable in index files                             *)
      (* Example: "x ' %x _% y %'x %'_' z" is encoded as                 *)
      (*   "x_''''_'%x'_'_%'_x_'%''x'_'%''_'''_x"                        *)
      let err () = eprintf "Invalid notation in globalization file\n"; exit 1 in
      let h = try String.index_from s 0 ':' with _ -> err () in
      let i = try String.index_from s (h+1) ':' with _ -> err () in
      let m = try String.index_from s (i+1) ':' with _ -> err () in
      let entry = String.sub s (h+1) (i-h-1) in
      let sc = String.sub s (i+1) (m-i-1) in
      let ntn = Bytes.make (String.length s - m) ' ' in
      let k = ref 0 in
      let j = ref (m+1) in
      let quoted = ref false in
      let l = String.length s - 1 in
      while !j <= l do
	if not !quoted then begin
	  (match s.[!j] with
	  | '_' -> Bytes.set ntn !k ' '; incr k
	  | 'x' -> Bytes.set ntn !k '_'; incr k
	  | '\'' -> quoted := true
	  | _ -> assert false)
	end
	else
	  if s.[!j] = '\'' then
	    if (!j = l || s.[!j+1] = '_') then quoted := false
	    else (incr j; Bytes.set ntn !k s.[!j]; incr k)
	  else begin
	    Bytes.set ntn !k s.[!j];
	    incr k
	  end;
	incr j
      done;
      let ntn = Bytes.sub_string ntn 0 !k in
      let ntn = if sc = "" then ntn else ntn ^ " (" ^ sc ^ ")" in
      if entry = "" then ntn else entry ^ ":" ^ ntn
  | _ ->
      s

let all_entries () =
  let gl = ref [] in
  let add_g s m t = gl := (s,(m,t)) :: !gl in
  let bt = Hashtbl.create 11 in
  let add_bt t s m =
    let l = try Hashtbl.find bt t with Not_found -> [] in
      Hashtbl.replace bt t ((s,m) :: l)
  in
  let classify m (s,t) = (add_g s m t; add_bt t s m) in
    Hashtbl.iter classify deftable;
    Hashtbl.iter (fun id m -> add_g id m Library; add_bt Library id m) modules;
    { idx_name = "global";
      idx_entries = sort_entries !gl;
      idx_size = List.length !gl },
    Hashtbl.fold (fun t e l -> (t, { idx_name = type_name t;
			             idx_entries = sort_entries e;
			             idx_size = List.length e }) :: l) bt []

let type_of_string = function
  | "def" | "coe" | "subclass" | "canonstruc" | "fix" | "cofix"
  | "ex" | "scheme" -> Definition
  | "prf" | "thm" -> Lemma
  | "ind" | "variant" | "coind" -> Inductive
  | "constr" -> Constructor
  | "indrec" | "rec" | "corec" -> Record
  | "proj" -> Projection
  | "class" -> Class
  | "meth" -> Method
  | "inst" -> Instance
  | "var" -> Variable
  | "defax" | "prfax" | "ax" -> Axiom
  | "syndef" -> Abbreviation
  | "not" -> Notation
  | "lib" -> Library
  | "mod" | "modtype" -> Module
  | "tac" -> TacticDefinition
  | "sec" -> Section
  | s -> invalid_arg ("type_of_string:" ^ s)

let ill_formed_glob_file f =
  eprintf "Warning: ill-formed file %s (links will not be available)\n" f
let outdated_glob_file f =
  eprintf "Warning: %s not consistent with corresponding .v file (links will not be available)\n" f

let correct_file vfile f c =
  let s = input_line c in
  if String.length s < 7 || String.sub s 0 7 <> "DIGEST " then
    (ill_formed_glob_file f; false)
  else
    let s = String.sub s 7 (String.length s - 7) in
    match vfile, s with
    | None, "NO" -> true
    | Some _, "NO" -> ill_formed_glob_file f; false
    | None, _ -> ill_formed_glob_file f; false
    | Some vfile, s ->
        s = Digest.to_hex (Digest.file vfile) || (outdated_glob_file f; false)

let read_glob vfile f =
  let c = open_in f in
  if correct_file vfile f c then
  let cur_mod = ref "" in
  try
    while true do
      let s = input_line c in
      let n = String.length s in
      if n > 0 then begin
	match s.[0] with
	  | 'F' ->
	      cur_mod := String.sub s 1 (n - 1);
	      current_library := !cur_mod
	  | 'R' ->
	      (try
		Scanf.sscanf s "R%d:%d %s %s %s %s"
		  (fun loc1 loc2 lib_dp sp id ty ->
		    for loc=loc1 to loc2 do
		      add_ref !cur_mod loc lib_dp sp id (type_of_string ty);

                      (* Also add an entry for each module mentioned in [lib_dp],
                       * to use in interpolation. *)
                      ignore (List.fold_right (fun thisPiece priorPieces ->
                                                let newPieces = match priorPieces with
                                                                | "" -> thisPiece
                                                                | _ -> thisPiece ^ "." ^ priorPieces in
                                                add_ref !cur_mod loc "" "" newPieces Library;
                                                newPieces) (Str.split (Str.regexp_string ".") lib_dp) "")
		    done)
	       with _ -> ())
	  | _ ->
	      try Scanf.sscanf s "%s %d:%d %s %s"
		(fun ty loc1 loc2 sp id ->
                  add_def loc1 loc2 (type_of_string ty) sp id)
	      with Scanf.Scan_failure _ -> ()

      end
    done; assert false
  with End_of_file ->
    close_in c