(* Yoann Padioleau
 *
 * Copyright (C) 2010, University of Copenhagen DIKU and INRIA.
 * Copyright (C) 2007, 2008 Ecole des Mines de Nantes
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License (GPL)
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * file license.txt for more details.
 *)

open Common

module TH = Token_helpers

open Parser_c

(*****************************************************************************)
(* Some debugging functions  *)
(*****************************************************************************)

let pr2, pr2_once = Common.mk_pr2_wrappers Flag_parsing_c.verbose_parsing

(* ------------------------------------------------------------------------- *)
(* fuzzy parsing, different "views" over the same program *)
(* ------------------------------------------------------------------------- *)


(* Normally I should not use ref/mutable in the token_extended type
 * and I should have a set of functions taking a list of tokens and
 * returning a list of tokens. The problem is that to make easier some
 * functions, it is better to work on better representation, on "views"
 * over this list of tokens. But then modifying those views and get
 * back from those views to the original simple list of tokens is
 * tedious. One way is to maintain next to the view a list of "actions"
 * (I was using a hash storing the charpos of the token and associating
 * the action) but it is tedious too. Simpler to use mutable/ref. We
 * use the same idea that we use when working on the Ast_c. *)

(* old: when I was using the list of "actions" next to the views, the hash
 * indexed by the charpos, there could have been some problems:
 * how my fake_pos interact with the way I tag and adjust token ?
 * because I base my tagging on the position of the token ! so sometimes
 * could tag another fakeInfo that should not be tagged ?
 * fortunately I don't use anymore this technique.
 *)

(* update: quite close to the Place_c.Inxxx *)
type context =
  InFunction | InEnum | InStruct | InInitializer | NoContext

type token_extended = {
  mutable tok: Parser_c.token;
  mutable where: context;

  (* less: need also a after ? *)
  mutable new_tokens_before : Parser_c.token list;

  (* line x col  cache, more easily accessible, of the info in the token *)
  line: int;
  col : int;
}

(* todo? is it ok to reset as a comment a TDefEOL ? if do that, then
 * can confuse the parser.
 *)
let set_as_comment cppkind x =
  if TH.is_eof x.tok
  then () (* otherwise parse_c will be lost if don't find a EOF token *)
  else
    x.tok <- TCommentCpp (cppkind, TH.info_of_tok x.tok)

let save_as_comment cppkind x =
  if TH.is_eof x.tok
  then () (* otherwise parse_c will be lost if don't find a EOF token *)
  else
    let t =
      match x.tok with
	TIfdef _ | TIfdefMisc _ | TIfdefVersion _ -> Token_c.IfDef
      | TIfdefBool _ -> Token_c.IfDef0
      | TIfdefelse _ | TIfdefelif _ -> Token_c.Else
      | TEndif _ -> Token_c.Endif
      | _ -> Token_c.Other in
    x.tok <- TCommentCpp (cppkind t, TH.info_of_tok x.tok)

let mk_token_extended x =
  let (line, col) = TH.linecol_of_tok x in
  { tok = x;
    line = line; col = col;
    where = NoContext;
    new_tokens_before = [];
  }

let rebuild_tokens_extented toks_ext =
  List.rev
    (List.fold_left
       (function prev ->
	 function tok ->
	   (mk_token_extended tok.tok) ::
	   List.fold_left
	     (function prev ->
	       function bef ->
		 (mk_token_extended bef)::prev)
	     prev tok.new_tokens_before)
       [] toks_ext)

(* x list list, because x list separated by ',' *)
type paren_grouped =
  | Parenthised   of paren_grouped list list * token_extended list
  | PToken of token_extended

type brace_grouped =
  | Braceised   of
      brace_grouped list list * token_extended * token_extended option
  | BToken of token_extended

(* Far better data structure than doing hacks in the lexer or parser
 * because in lexer we don't know to which ifdef a endif is related
 * and so when we want to comment a ifdef, we don't know which endif
 * we must also comment. Especially true for the #if 0 which sometimes
 * have a #else part.
 *
 * x list list, because x list separated by #else or #elif
 *)
type ifdef_grouped =
  (*
   * Example:
   *
   *     #ifdef A
   *       x++;
   *     #else
   *       x--;
   *     #endif
   *
   *   is represented as Ifdef ([[x++];[x--]],[#ifdef A;#else;#endif])
   *   where x++ and x-- are NoIfdefLine.
   *
   * /Iago
   *)
  | Ifdef     of ifdef_grouped list list * token_extended list
  | Ifdefbool of bool * ifdef_grouped list list * token_extended list
  | NotIfdefLine of token_extended list


type 'a line_grouped =
  Line of 'a list


type body_function_grouped =
  | BodyFunction of token_extended list
  | NotBodyLine  of token_extended list


(* ------------------------------------------------------------------------- *)
(* view builders  *)
(* ------------------------------------------------------------------------- *)

(* todo: synchro ! use more indentation
 * if paren not closed and same indentation level, certainly because
 * part of a mid-ifdef-expression.
*)
let rec mk_parenthised xs =
  let rec loop acc = function
  | [] -> acc
  | x::xs ->
      (match x.tok with
      | TOPar _ | TOParDefine _ ->
          let body, extras, xs = mk_parameters [x] [] xs in
          loop (Parenthised (body,extras)::acc) xs
      | _ ->
          loop (PToken x::acc) xs
      ) in
  List.rev(loop [] xs)

(* return the body of the parenthised expression and the rest of the tokens *)
and mk_parameters extras acc_before_sep  xs =
  match xs with
  | [] ->
      (* maybe because of #ifdef which "opens" '(' in 2 branches *)
      pr2 "PB: not found closing paren in fuzzy parsing";
      [List.rev acc_before_sep], List.rev extras, []
  | x::xs ->
      (match x.tok with
      (* synchro *)
      | TOBrace _ when x.col = 0 ->
          pr2 "PB: found synchro point } in paren";
          [List.rev acc_before_sep], List.rev (extras), (x::xs)

      | TCPar _ | TCParEOL _ ->
          [List.rev acc_before_sep], List.rev (x::extras), xs
      | TOPar _ | TOParDefine _ ->
          let body, extrasnest, xs = mk_parameters [x] [] xs in
          mk_parameters extras
            (Parenthised (body,extrasnest)::acc_before_sep)
            xs
      | TComma _ ->
          let body, extras, xs = mk_parameters (x::extras) [] xs in
          (List.rev acc_before_sep)::body, extras, xs
      | _ ->
          mk_parameters extras (PToken x::acc_before_sep) xs
      )




let rec mk_braceised xs =
  let rec loop acc = function
    | [] -> acc
    | x::xs ->
	(match x.tok with
	| TOBrace _ ->
            let body, endbrace, xs = mk_braceised_aux [] xs in
            loop (Braceised (body, x, endbrace)::acc) xs
	| TCBrace _ ->
            pr2 (Printf.sprintf
		   "PB: found closing brace alone at line %d in fuzzy parsing"
		   x.line);
            loop (BToken x::acc) xs
	| _ ->
            loop (BToken x::acc) xs) in
  List.rev(loop [] xs)

(* return the body of the parenthised expression and the rest of the tokens *)
and mk_braceised_aux acc xs =
  match xs with
  | [] ->
      (* maybe because of #ifdef which "opens" '(' in 2 branches *)
      pr2 "PB: not found closing brace in fuzzy parsing";
      [List.rev acc], None, []
  | x::xs ->
      (match x.tok with
      | TCBrace _ -> [List.rev acc], Some x, xs
      | TOBrace _ ->
          let body, endbrace, xs = mk_braceised_aux [] xs in
          mk_braceised_aux  (Braceised (body,x, endbrace)::acc) xs
      | _ ->
          mk_braceised_aux (BToken x::acc) xs
      )




let rec mk_ifdef xs =
  match xs with
  | [] -> []
  | x::xs ->
      (match x.tok with
      | TIfdef _ ->
          let body, extra, xs' = mk_ifdef_parameters [x] [] xs in
          Ifdef (body, extra)::mk_ifdef xs'
      | TIfdefBool (b,_, _) ->
          let body, extra, xs' = mk_ifdef_parameters [x] [] xs in

          (* if not passing, then consider a #if 0 as an ordinary #ifdef *)
          if !Flag_parsing_c.if0_passing
          then Ifdefbool (b, body, extra)::mk_ifdef xs'
          else Ifdef(body, extra)::mk_ifdef xs'

      | TIfdefMisc (b,_,_) | TIfdefVersion (b,_,_) ->
          let body, extra, xs' = mk_ifdef_parameters [x] [] xs in
          Ifdefbool (b, body, extra)::mk_ifdef xs'


      | _ ->
          (* todo? can have some Ifdef in the line ? *)
          let line, xs' = Common.span (fun y -> y.line = x.line) (x::xs) in
          NotIfdefLine line::mk_ifdef xs'
      )

and mk_ifdef_parameters extras acc_before_sep xs =
  match xs with
  | [] ->
      (* Note that mk_ifdef is assuming that CPP instruction are alone
       * on their line. Because I do a span (fun x -> is_same_line ...)
       * I might take with me a #endif if this one is mixed on a line
       * with some "normal" tokens.
       *)
      pr2 "PB: not found closing ifdef in fuzzy parsing";
      [List.rev acc_before_sep], List.rev extras, []
  | x::xs ->
      (match x.tok with
      | TEndif _ ->
          [List.rev acc_before_sep], List.rev (x::extras), xs
      | TIfdef _ ->
          let body, extrasnest, xs = mk_ifdef_parameters [x] [] xs in
          mk_ifdef_parameters
            extras (Ifdef (body, extrasnest)::acc_before_sep) xs

      | TIfdefBool (b,_,_) ->
          let body, extrasnest, xs = mk_ifdef_parameters [x] [] xs in

          if !Flag_parsing_c.if0_passing
          then
            mk_ifdef_parameters
              extras (Ifdefbool (b, body, extrasnest)::acc_before_sep) xs
          else
            mk_ifdef_parameters
              extras (Ifdef (body, extrasnest)::acc_before_sep) xs


      | TIfdefMisc (b,_,_) | TIfdefVersion (b,_,_) ->
          let body, extrasnest, xs = mk_ifdef_parameters [x] [] xs in
          mk_ifdef_parameters
            extras (Ifdefbool (b, body, extrasnest)::acc_before_sep) xs

      | TIfdefelse _
      | TIfdefelif _ ->
          let body, extras, xs = mk_ifdef_parameters (x::extras) [] xs in
          (List.rev acc_before_sep)::body, extras, xs
      | _ ->
          let line, xs = Common.span (fun y -> y.line = x.line) (x::xs) in
          mk_ifdef_parameters extras (NotIfdefLine line::acc_before_sep) xs
      )

(* --------------------------------------- *)

let line_of_paren = function
  | PToken x -> x.line
  | Parenthised (xxs, info_parens) ->
      (match info_parens with
      | [] -> raise (Impossible 121)
      | x::xs -> x.line
      )


let rec span_line_paren line = function
  | [] -> [],[]
  | x::xs ->
      (match x with
      | PToken tok when TH.is_eof tok.tok ->
          [], x::xs
      | _ ->
        if line_of_paren x = line
        then
          let (l1, l2) = span_line_paren line xs in
          (x::l1, l2)
        else ([], x::xs)
      )


let rec mk_line_parenthised xs =
  match xs with
  | [] -> []
  | x::xs ->
      let line_no = line_of_paren x in
      let line, xs = span_line_paren line_no xs in
      Line (x::line)::mk_line_parenthised xs


(* --------------------------------------- *)
let rec mk_body_function_grouped xs =
  match xs with
  | [] -> []
  | x::xs ->
      (match x with
      | {tok = TOBrace _; col = 0} ->
          let is_closing_brace = function
            | {tok = TCBrace _; col = 0 } -> true
            | _ -> false
          in
          let body, xs = Common.span (fun x -> not (is_closing_brace x)) xs in
          (match xs with
          | ({tok = TCBrace _; col = 0 })::xs ->
              BodyFunction body::mk_body_function_grouped xs
          | [] ->
              pr2 "PB:not found closing brace in fuzzy parsing";
              [NotBodyLine body]
          | _ -> raise (Impossible 122)
          )

      | _ ->
          let line, xs = Common.span (fun y -> y.line = x.line) (x::xs) in
          NotBodyLine line::mk_body_function_grouped xs
      )


(* ------------------------------------------------------------------------- *)
(* view iterators  *)
(* ------------------------------------------------------------------------- *)

let rec iter_token_paren f xs =
  xs +> List.iter (function
  | PToken tok -> f tok;
  | Parenthised (xxs, info_parens) ->
      info_parens +> List.iter f;
      xxs +> List.iter (fun xs -> iter_token_paren f xs)
  )

let rec iter_token_brace f xs =
  xs +> List.iter (function
  | BToken tok -> f tok;
  | Braceised (xxs, tok1, tok2opt) ->
      f tok1; do_option f tok2opt;
      xxs +> List.iter (fun xs -> iter_token_brace f xs)
  )

let rec iter_token_ifdef f xs =
  xs +> List.iter (function
  | NotIfdefLine xs -> xs +> List.iter f;
  | Ifdefbool (_, xxs, info_ifdef)
  | Ifdef (xxs, info_ifdef) ->
      info_ifdef +> List.iter f;
      xxs +> List.iter (iter_token_ifdef f)
  )




let tokens_of_paren xs =
  let g = ref [] in
  xs +> iter_token_paren (fun tok -> push2 tok g);
  List.rev !g


let tokens_of_paren_ordered xs =
  let g = ref [] in

  let rec aux_tokens_ordered = function
    | PToken tok -> push2 tok g;
    | Parenthised (xxs, info_parens) ->
        let (opar, cpar, commas) =
          match info_parens with
          | opar::xs ->
              (match List.rev xs with
              | cpar::xs ->
                  opar, cpar, List.rev xs
              | _ -> raise (Impossible 123)
              )
          | _ -> raise (Impossible 124)
        in
        push2 opar g;
        aux_args (xxs,commas);
        push2 cpar g;

  and aux_args (xxs, commas) =
    match xxs, commas with
    | [], [] -> ()
    | [xs], [] -> xs +> List.iter aux_tokens_ordered
    | xs::ys::xxs, comma::commas ->
        xs +> List.iter aux_tokens_ordered;
        push2 comma g;
        aux_args (ys::xxs, commas)
    | _ -> () (* case may occur with unmatched parentheses in #define *)

  in

  xs +> List.iter aux_tokens_ordered;
  List.rev !g



(* ------------------------------------------------------------------------- *)
(* set the context info in token *)
(* ------------------------------------------------------------------------- *)


let rec set_in_function_tag xs =
 (* could try: ) { } but it can be the ) of a if or while, so
  * better to base the heuristic on the position in column zero.
  * Note that some struct or enum or init put also their { in first column
  * but set_in_other will overwrite the previous InFunction tag.
  *)
  match xs with
  | [] -> ()
  (* ) { and the closing } is in column zero, then certainly a function *)
  | BToken ({tok = TCPar _ })::(Braceised (body, tok1, Some tok2))::xs
      when tok1.col <> 0 && tok2.col = 0 ->
      body +> List.iter (iter_token_brace (fun tok ->
        tok.where <- InFunction
      ));
      set_in_function_tag xs

  | (BToken x)::xs -> set_in_function_tag xs

  | (Braceised (body, tok1, Some tok2))::xs
      when tok1.col = 0 && tok2.col = 0 ->
      body +> List.iter (iter_token_brace (fun tok ->
        tok.where <- InFunction
      ));
      set_in_function_tag xs
  | Braceised (body, tok1, tok2)::xs ->
      set_in_function_tag xs


let rec set_in_other xs =
  match xs with
  | [] -> ()
  (* enum x { } *)
  | BToken ({tok = Tenum _})::BToken ({tok = TIdent _})
    ::Braceised(body, tok1, tok2)::xs
  | BToken ({tok = Tenum _})
    ::Braceised(body, tok1, tok2)::xs
    ->
      body +> List.iter (iter_token_brace (fun tok ->
        tok.where <- InEnum;
      ));
      set_in_other xs

  (* struct x { } *)
  | BToken ({tok = Tstruct _})::BToken ({tok = TIdent _})
    ::Braceised(body, tok1, tok2)::xs ->
      body +> List.iter (iter_token_brace (fun tok ->
        tok.where <- InStruct;
      ));
      set_in_other xs
  (* = { } *)
  | BToken ({tok = TEq _})
    ::Braceised(body, tok1, tok2)::xs ->
      body +> List.iter (iter_token_brace (fun tok ->
        tok.where <- InInitializer;
      ));
      set_in_other xs

  | BToken _::xs -> set_in_other xs

  | Braceised(body, tok1, tok2)::xs ->
      body +> List.iter set_in_other;
      set_in_other xs




let set_context_tag xs =
  begin
    set_in_function_tag xs;
    set_in_other xs;
  end
