(************************************************************************)
(*         *   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 CErrors
open Util
open Extend
open Genarg

let curry f x y = f (x, y)
let uncurry f (x,y) = f x y

(** Location Utils  *)
let ploc_file_of_coq_file = function
| Loc.ToplevelInput -> ""
| Loc.InFile f -> f

let coq_file_of_ploc_file s =
  if s = "" then Loc.ToplevelInput else Loc.InFile s

let of_coqloc loc =
  let open Loc in
  Ploc.make_loc (ploc_file_of_coq_file loc.fname) loc.line_nb loc.bol_pos (loc.bp, loc.ep) ""

let to_coqloc loc =
  { Loc.fname = coq_file_of_ploc_file (Ploc.file_name loc);
    Loc.line_nb = Ploc.line_nb loc;
    Loc.bol_pos = Ploc.bol_pos loc;
    Loc.bp = Ploc.first_pos loc;
    Loc.ep = Ploc.last_pos loc;
    Loc.line_nb_last = Ploc.line_nb_last loc;
    Loc.bol_pos_last = Ploc.bol_pos_last loc; }

let (!@) = to_coqloc

(** The parser of Coq *)
module G : sig

  include Grammar.S with type te = Tok.t

(* where Grammar.S

module type S =
  sig
    type te = 'x;
    type parsable = 'x;
    value parsable : Stream.t char -> parsable;
    value tokens : string -> list (string * int);
    value glexer : Plexing.lexer te;
    value set_algorithm : parse_algorithm -> unit;
    module Entry :
      sig
        type e 'a = 'y;
        value create : string -> e 'a;
        value parse : e 'a -> parsable -> 'a;
        value parse_token : e 'a -> Stream.t te -> 'a;
        value name : e 'a -> string;
        value of_parser : string -> (Stream.t te -> 'a) -> e 'a;
        value print : Format.formatter -> e 'a -> unit;
        external obj : e 'a -> Gramext.g_entry te = "%identity";
      end
    ;
    module Unsafe :
      sig
        value gram_reinit : Plexing.lexer te -> unit;
        value clear_entry : Entry.e 'a -> unit;
      end
    ;
    value extend :
      Entry.e 'a -> option Gramext.position ->
        list
          (option string * option Gramext.g_assoc *
           list (list (Gramext.g_symbol te) * Gramext.g_action)) ->
        unit;
    value delete_rule : Entry.e 'a -> list (Gramext.g_symbol te) -> unit;
  end
  *)

  type 'a entry = 'a Entry.e
  type internal_entry = Tok.t Gramext.g_entry
  type symbol = Tok.t Gramext.g_symbol
  type action = Gramext.g_action
  type coq_parsable

  val coq_parsable : ?file:Loc.source -> char Stream.t -> coq_parsable
  val action : 'a -> action
  val entry_create : string -> 'a entry
  val entry_parse : 'a entry -> coq_parsable -> 'a

  val comment_state : coq_parsable -> ((int * int) * string) list

end with type 'a Entry.e = 'a Grammar.GMake(CLexer).Entry.e = struct

  include Grammar.GMake(CLexer)

  type 'a entry = 'a Entry.e
  type internal_entry = Tok.t Gramext.g_entry
  type symbol = Tok.t Gramext.g_symbol
  type action = Gramext.g_action

  type coq_parsable = parsable * CLexer.lexer_state ref

  let coq_parsable ?(file=Loc.ToplevelInput) c =
    let state = ref (CLexer.init_lexer_state file) in
    CLexer.set_lexer_state !state;
    let a = parsable c in
    state := CLexer.get_lexer_state ();
    (a,state)

  let action = Gramext.action
  let entry_create = Entry.create

  let entry_parse e (p,state) =
    CLexer.set_lexer_state !state;
    try
      let c = Entry.parse e p in
      state := CLexer.get_lexer_state ();
      c
    with Ploc.Exc (loc,e) ->
      CLexer.drop_lexer_state ();
      let loc' = Loc.get_loc (Exninfo.info e) in
      let loc = match loc' with None -> to_coqloc loc | Some loc -> loc in
      Loc.raise ~loc e

  let comment_state (p,state) =
    CLexer.get_comment_state !state

end

module Parsable =
struct
  type t = G.coq_parsable
  let make = G.coq_parsable
  let comment_state = G.comment_state
end

module Entry =
struct

  type 'a t = 'a Grammar.GMake(CLexer).Entry.e

  let create = G.Entry.create
  let parse = G.entry_parse
  let print = G.Entry.print

end

let warning_verbose = Gramext.warning_verbose

let of_coq_assoc = function
| Extend.RightA -> Gramext.RightA
| Extend.LeftA -> Gramext.LeftA
| Extend.NonA -> Gramext.NonA

let of_coq_position = function
| Extend.First -> Gramext.First
| Extend.Last -> Gramext.Last
| Extend.Before s -> Gramext.Before s
| Extend.After s -> Gramext.After s
| Extend.Level s -> Gramext.Level s

module Symbols : sig
  val stoken : Tok.t -> G.symbol
  val sself : G.symbol
  val snext : G.symbol
  val slist0 : G.symbol -> G.symbol
  val slist0sep : G.symbol * G.symbol -> G.symbol
  val slist1 : G.symbol -> G.symbol
  val slist1sep : G.symbol * G.symbol -> G.symbol
  val sopt : G.symbol -> G.symbol
  val snterml : G.internal_entry * string -> G.symbol
  val snterm : G.internal_entry -> G.symbol
end = struct

  let stoken tok =
    let pattern = match tok with
    | Tok.KEYWORD s -> "", s
    | Tok.IDENT s -> "IDENT", s
    | Tok.PATTERNIDENT s -> "PATTERNIDENT", s
    | Tok.FIELD s -> "FIELD", s
    | Tok.INT s -> "INT", s
    | Tok.STRING s -> "STRING", s
    | Tok.LEFTQMARK -> "LEFTQMARK", ""
    | Tok.BULLET s -> "BULLET", s
    | Tok.EOI -> "EOI", ""
    in
    Gramext.Stoken pattern

     let slist0sep (x, y) = Gramext.Slist0sep (x, y, false)
     let slist1sep (x, y) = Gramext.Slist1sep (x, y, false)

  let snterml (x, y) = Gramext.Snterml (x, y)
  let snterm x = Gramext.Snterm x
  let sself = Gramext.Sself
  let snext = Gramext.Snext
  let slist0 x = Gramext.Slist0 x
  let slist1 x = Gramext.Slist1 x
  let sopt x = Gramext.Sopt x

end

let camlp5_verbosity silent f x =
  let a = !warning_verbose in
  warning_verbose := silent;
  f x;
  warning_verbose := a

(** Grammar extensions *)

(** NB: [extend_statement =
         gram_position option * single_extend_statement list]
    and [single_extend_statement =
         string option * gram_assoc option * production_rule list]
    and [production_rule = symbol list * action]

    In [single_extend_statement], first two parameters are name and
    assoc iff a level is created *)

(** Binding general entry keys to symbol *)

let rec of_coq_action : type a r. (r, a, Loc.t -> r) Extend.rule -> a -> G.action = function
| Stop -> fun f -> G.action (fun loc -> f (!@ loc))
| Next (r, _) -> fun f -> G.action (fun x -> of_coq_action r (f x))

let rec symbol_of_prod_entry_key : type s a. (s, a) symbol -> _ = function
  | Atoken t -> Symbols.stoken t
  | Alist1 s -> Symbols.slist1 (symbol_of_prod_entry_key s)
  | Alist1sep (s,sep) ->
      Symbols.slist1sep (symbol_of_prod_entry_key s, symbol_of_prod_entry_key sep)
  | Alist0 s -> Symbols.slist0 (symbol_of_prod_entry_key s)
  | Alist0sep (s,sep) ->
      Symbols.slist0sep (symbol_of_prod_entry_key s, symbol_of_prod_entry_key sep)
  | Aopt s -> Symbols.sopt (symbol_of_prod_entry_key s)
  | Aself -> Symbols.sself
  | Anext -> Symbols.snext
  | Aentry e ->
    Symbols.snterm (G.Entry.obj e)
  | Aentryl (e, n) ->
    Symbols.snterml (G.Entry.obj e, n)
  | Arules rs ->
    Gramext.srules (List.map symbol_of_rules rs)

and symbol_of_rule : type s a r. (s, a, r) Extend.rule -> _ = function
| Stop -> fun accu -> accu
| Next (r, s) -> fun accu -> symbol_of_rule r (symbol_of_prod_entry_key s :: accu)

and symbol_of_rules : type a. a Extend.rules -> _ = function
| Rules (r, act) ->
  let symb = symbol_of_rule r.norec_rule [] in
  let act = of_coq_action r.norec_rule act in
  (symb, act)

let of_coq_production_rule : type a. a Extend.production_rule -> _ = function
| Rule (toks, act) -> (symbol_of_rule toks [], of_coq_action toks act)

let of_coq_single_extend_statement (lvl, assoc, rule) =
  (lvl, Option.map of_coq_assoc assoc, List.map of_coq_production_rule rule)

let of_coq_extend_statement (pos, st) =
  (Option.map of_coq_position pos, List.map of_coq_single_extend_statement st)

(** Type of reinitialization data *)
type gram_reinit = gram_assoc * gram_position

type extend_rule =
| ExtendRule : 'a G.entry * gram_reinit option * 'a extend_statement -> extend_rule

type ext_kind =
  | ByGrammar of extend_rule
  | ByEXTEND of (unit -> unit) * (unit -> unit)

(** The list of extensions *)

let camlp5_state = ref []

(** Deletion *)

let grammar_delete e reinit (pos,rls) =
  List.iter
    (fun (n,ass,lev) ->
      List.iter (fun (pil,_) -> G.delete_rule e pil) (List.rev lev))
    (List.rev rls);
  match reinit with
  | Some (a,ext) ->
    let a = of_coq_assoc a in
    let ext = of_coq_position ext in
    let lev = match pos with
    | Some (Gramext.Level n) -> n
    | _ -> assert false
    in
    (G.extend e) (Some ext) [Some lev,Some a,[]]
  | None -> ()

(** Extension *)

let grammar_extend e reinit ext =
  let ext = of_coq_extend_statement ext in
  let undo () = grammar_delete e reinit ext in
  let redo () = camlp5_verbosity false (uncurry (G.extend e)) ext in
  camlp5_state := ByEXTEND (undo, redo) :: !camlp5_state;
  redo ()

let grammar_extend_sync e reinit ext =
  camlp5_state := ByGrammar (ExtendRule (e, reinit, ext)) :: !camlp5_state;
  camlp5_verbosity false (uncurry (G.extend e)) (of_coq_extend_statement ext)

(** The apparent parser of Coq; encapsulate G to keep track
    of the extensions. *)

module Gram =
  struct
    include G
    let extend e =
      curry
    (fun ext ->
      camlp5_state :=
        (ByEXTEND ((fun () -> grammar_delete e None ext),
           (fun () -> uncurry (G.extend e) ext)))
      :: !camlp5_state;
      uncurry (G.extend e) ext)
    let delete_rule e pil =
      (* spiwack: if you use load an ML module which contains GDELETE_RULE
      in a section, God kills a kitty. As it would corrupt remove_grammars.
          There does not seem to be a good way to undo a delete rule. As deleting
      takes fewer arguments than extending. The production rule isn't returned
      by delete_rule. If we could retrieve the necessary information, then
      ByEXTEND provides just the framework we need to allow this in section.
      I'm not entirely sure it makes sense, but at least it would be more correct.
          *)
      G.delete_rule e pil
    let gram_extend e ext = grammar_extend e None ext
  end

(** Remove extensions

   [n] is the number of extended entries (not the number of Grammar commands!)
   to remove. *)

let rec remove_grammars n =
  if n>0 then
    (match !camlp5_state with
       | [] -> anomaly ~label:"Pcoq.remove_grammars" (Pp.str "too many rules to remove.")
       | ByGrammar (ExtendRule (g, reinit, ext)) :: t ->
           grammar_delete g reinit (of_coq_extend_statement ext);
           camlp5_state := t;
           remove_grammars (n-1)
       | ByEXTEND (undo,redo)::t ->
           undo();
           camlp5_state := t;
           remove_grammars n;
           redo();
           camlp5_state := ByEXTEND (undo,redo) :: !camlp5_state)

let make_rule r = [None, None, r]

(** An entry that checks we reached the end of the input. *)

let eoi_entry en =
  let e = Entry.create ((Gram.Entry.name en) ^ "_eoi") in
  let symbs = [Symbols.snterm (Gram.Entry.obj en); Symbols.stoken Tok.EOI] in
  let act = Gram.action (fun _ x loc -> x) in
  uncurry (Gram.extend e) (None, make_rule [symbs, act]);
  e

let map_entry f en =
  let e = Entry.create ((Gram.Entry.name en) ^ "_map") in
  let symbs = [Symbols.snterm (Gram.Entry.obj en)] in
  let act = Gram.action (fun x loc -> f x) in
  uncurry (Gram.extend e) (None, make_rule [symbs, act]);
  e

(* Parse a string, does NOT check if the entire string was read
   (use eoi_entry) *)

let parse_string f x =
  let strm = Stream.of_string x in Gram.entry_parse f (Gram.coq_parsable strm)

type gram_universe = string

let utables : (string, unit) Hashtbl.t =
  Hashtbl.create 97

let create_universe u =
  let () = Hashtbl.add utables u () in
  u

let uprim   = create_universe "prim"
let uconstr = create_universe "constr"
let utactic = create_universe "tactic"

let get_univ u =
  if Hashtbl.mem utables u then u
  else raise Not_found

let new_entry u s =
  let ename = u ^ ":" ^ s in
  let e = Entry.create ename in
  e

let make_gen_entry u s = new_entry u s

module GrammarObj =
struct
  type ('r, _, _) obj = 'r Entry.t
  let name = "grammar"
  let default _ = None
end

module Grammar = Register(GrammarObj)

let register_grammar = Grammar.register0
let genarg_grammar = Grammar.obj

let create_generic_entry (type a) u s (etyp : a raw_abstract_argument_type) : a Entry.t =
  let e = new_entry u s in
  let Rawwit t = etyp in
  let () = Grammar.register0 t e in
  e

(* Initial grammar entries *)

module Prim =
  struct
    let gec_gen n = make_gen_entry uprim n

    (* Entries that can be referred via the string -> Entry.t table *)
    (* Typically for tactic or vernac extensions *)
    let preident = gec_gen "preident"
    let ident = gec_gen "ident"
    let natural = gec_gen "natural"
    let integer = gec_gen "integer"
    let bigint = Entry.create "Prim.bigint"
    let string = gec_gen "string"
    let lstring = Entry.create "Prim.lstring"
    let reference = make_gen_entry uprim "reference"
    let by_notation = Entry.create "by_notation"
    let smart_global = Entry.create "smart_global"

    (* parsed like ident but interpreted as a term *)
    let var = gec_gen "var"

    let name = Entry.create "Prim.name"
    let identref = Entry.create "Prim.identref"
    let univ_decl = Entry.create "Prim.univ_decl"
    let ident_decl = Entry.create "Prim.ident_decl"
    let pattern_ident = Entry.create "pattern_ident"
    let pattern_identref = Entry.create "pattern_identref"

    (* A synonym of ident - maybe ident will be located one day *)
    let base_ident = Entry.create "Prim.base_ident"

    let qualid = Entry.create "Prim.qualid"
    let fullyqualid = Entry.create "Prim.fullyqualid"
    let dirpath = Entry.create "Prim.dirpath"

    let ne_string = Entry.create "Prim.ne_string"
    let ne_lstring = Entry.create "Prim.ne_lstring"

  end

module Constr =
  struct
    let gec_constr = make_gen_entry uconstr

    (* Entries that can be referred via the string -> Entry.t table *)
    let constr = gec_constr "constr"
    let operconstr = gec_constr "operconstr"
    let constr_eoi = eoi_entry constr
    let lconstr = gec_constr "lconstr"
    let binder_constr = gec_constr "binder_constr"
    let ident = make_gen_entry uconstr "ident"
    let global = make_gen_entry uconstr "global"
    let universe_level = make_gen_entry uconstr "universe_level"
    let sort = make_gen_entry uconstr "sort"
    let sort_family = make_gen_entry uconstr "sort_family"
    let pattern = Entry.create "constr:pattern"
    let constr_pattern = gec_constr "constr_pattern"
    let lconstr_pattern = gec_constr "lconstr_pattern"
    let closed_binder = Entry.create "constr:closed_binder"
    let binder = Entry.create "constr:binder"
    let binders = Entry.create "constr:binders"
    let open_binders = Entry.create "constr:open_binders"
    let binders_fixannot = Entry.create "constr:binders_fixannot"
    let typeclass_constraint = Entry.create "constr:typeclass_constraint"
    let record_declaration = Entry.create "constr:record_declaration"
    let appl_arg = Entry.create "constr:appl_arg"
  end

module Module =
  struct
    let module_expr = Entry.create "module_expr"
    let module_type = Entry.create "module_type"
  end

let epsilon_value f e =
  let r = Rule (Next (Stop, e), fun x _ -> f x) in
  let ext = of_coq_extend_statement (None, [None, None, [r]]) in
  let entry = Gram.entry_create "epsilon" in
  let () = uncurry (G.extend entry) ext in
  try Some (parse_string entry "") with _ -> None

(** Synchronized grammar extensions *)

module GramState = Store.Make ()

type 'a grammar_extension = 'a -> GramState.t -> extend_rule list * GramState.t

module GrammarCommand = Dyn.Make ()
module GrammarInterp = struct type 'a t = 'a grammar_extension end
module GrammarInterpMap = GrammarCommand.Map(GrammarInterp)

let grammar_interp = ref GrammarInterpMap.empty

let (grammar_stack : (int * GrammarCommand.t * GramState.t) list ref) = ref []

type 'a grammar_command = 'a GrammarCommand.tag

let create_grammar_command name interp : _ grammar_command =
  let obj = GrammarCommand.create name in
  let () = grammar_interp := GrammarInterpMap.add obj interp !grammar_interp in
  obj

let extend_grammar_command tag g =
  let modify = GrammarInterpMap.find tag !grammar_interp in
  let grammar_state = match !grammar_stack with
  | [] -> GramState.empty
  | (_, _, st) :: _ -> st
  in
  let (rules, st) = modify g grammar_state in
  let iter (ExtendRule (e, reinit, ext)) = grammar_extend_sync e reinit ext in
  let () = List.iter iter rules in
  let nb = List.length rules in
  grammar_stack := (nb, GrammarCommand.Dyn (tag, g), st) :: !grammar_stack

let recover_grammar_command (type a) (tag : a grammar_command) : a list =
  let filter : _ -> a option = fun (_, GrammarCommand.Dyn (tag', v), _) ->
    match GrammarCommand.eq tag tag' with
    | None -> None
    | Some Refl -> Some v
  in
  List.map_filter filter !grammar_stack

let extend_dyn_grammar (GrammarCommand.Dyn (tag, g)) = extend_grammar_command tag g

(* Summary functions: the state of the lexer is included in that of the parser.
   Because the grammar affects the set of keywords when adding or removing
   grammar rules. *)
type frozen_t = (int * GrammarCommand.t * GramState.t) list * CLexer.keyword_state

let freeze _ : frozen_t = (!grammar_stack, CLexer.get_keyword_state ())

(* We compare the current state of the grammar and the state to unfreeze,
   by computing the longest common suffixes *)
let factorize_grams l1 l2 =
  if l1 == l2 then ([], [], l1) else List.share_tails l1 l2

let number_of_entries gcl =
  List.fold_left (fun n (p,_,_) -> n + p) 0 gcl

let unfreeze (grams, lex) =
  let (undo, redo, common) = factorize_grams !grammar_stack grams in
  let n = number_of_entries undo in
  remove_grammars n;
  grammar_stack := common;
  CLexer.set_keyword_state lex;
  List.iter extend_dyn_grammar (List.rev_map pi2 redo)

(** No need to provide an init function : the grammar state is
    statically available, and already empty initially, while
    the lexer state should not be resetted, since it contains
    keywords declared in g_*.ml4 *)

let parser_summary_tag =
  Summary.declare_summary_tag "GRAMMAR_LEXER"
    { Summary.freeze_function = freeze;
      Summary.unfreeze_function = unfreeze;
      Summary.init_function = Summary.nop }

let with_grammar_rule_protection f x =
  let fs = freeze false in
  try let a = f x in unfreeze fs; a
  with reraise ->
    let reraise = CErrors.push reraise in
    let () = unfreeze fs in
    iraise reraise

(** Registering grammar of generic arguments *)

let () =
  let open Stdarg in
  Grammar.register0 wit_int (Prim.integer);
  Grammar.register0 wit_string (Prim.string);
  Grammar.register0 wit_pre_ident (Prim.preident);
  Grammar.register0 wit_ident (Prim.ident);
  Grammar.register0 wit_var (Prim.var);
  Grammar.register0 wit_ref (Prim.reference);
  Grammar.register0 wit_sort_family (Constr.sort_family);
  Grammar.register0 wit_constr (Constr.constr);
  ()

(** Registering extra grammar *)

type any_entry = AnyEntry : 'a Entry.t -> any_entry

let grammar_names : any_entry list String.Map.t ref = ref String.Map.empty

let register_grammars_by_name name grams =
  grammar_names := String.Map.add name grams !grammar_names

let find_grammars_by_name name =
  String.Map.find name !grammar_names