(* Copyright (C) 2005, HELM Team.
 * 
 * This file is part of HELM, an Hypertextual, Electronic
 * Library of Mathematics, developed at the Computer Science
 * Department, University of Bologna, Italy.
 * 
 * HELM is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * HELM 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
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HELM; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA  02111-1307, USA.
 * 
 * For details, see the HELM World-Wide-Web page,
 * http://helm.cs.unibo.it/
 *)

(* $Id: cicNotationLexer.ml 11231 2011-03-30 11:52:27Z ricciott $ *)

open Printf

exception Error of int * int * string

module StringSet = Set.Make(String)

(* Lexer *)
let regexp number = xml_digit+
let regexp utf8_blank = " " | "\r\n" | "\n" | "\t" | [160] (* this is a nbsp *)
let regexp percentage = 
  ('-' | "") [ '0' - '9' ] + '%'
let regexp floatwithunit = 
  ('-' | "") [ '0' - '9' ] + ["."] [ '0' - '9' ] + ([ 'a' - 'z' ] + | "" )
let regexp color = "#" [ '0' - '9' 'a' - 'f' 'A' - 'F' ] [ '0' - '9' 'a' - 'f'
'A' - 'F' ] [ '0' - '9' 'a' - 'f' 'A' - 'F' ] [ '0' - '9' 'a' - 'f' 'A' - 'F' ]
[ '0' - '9' 'a' - 'f' 'A' - 'F' ] [ '0' - '9' 'a' - 'f' 'A' - 'F' ]

  (* ZACK: breaks unicode's binder followed by an ascii letter without blank *)
(* let regexp ident_letter = xml_letter *)

let regexp ident_letter = [ 'a' - 'z' 'A' - 'Z' ]

  (* must be in sync with "is_ligature_char" below *)
let regexp ligature_char = [ "'`~!?@*()[]<>-+=|:;.,/\"" ]
let regexp ligature = ligature_char ligature_char+

let regexp we_proved = "we" utf8_blank+ "proved"
let regexp we_have = "we" utf8_blank+ "have"
let regexp let_rec = "let" utf8_blank+ "rec" 
let regexp let_corec = "let" utf8_blank+  "corec"
let regexp ident_decoration = '\'' | '?' | '`'
let regexp ident_cont = ident_letter | xml_digit | '_'
let regexp ident_start = ident_letter 
let regexp ident = ident_letter ident_cont* ident_decoration* 
let regexp variable_ident = '_' '_' number
let regexp pident = '_' ident

let regexp uri_step = [ 'a' - 'z' 'A' - 'Z' '0' - '9' '_' '-' ''' ]+

let regexp uri =
  ("cic:/" | "theory:/")              (* schema *)
(*   ident ('/' ident)*                  |+ path +| *)
  uri_step ('/' uri_step)*            (* path *)
  ('.' ident)+                        (* ext *)
(*  ("#xpointer(" number ('/' number)+ ")")?  (* xpointer *) *)
  ("(" number (',' number)* ")")?  (* reference spec *)

let regexp qstring = '"' [^ '"']* '"'
let regexp hreftag = "<A"
let regexp href = "href=\"" uri "\""
let regexp hreftitle = "title=" qstring
let regexp hrefclose = "</A>"

let regexp tex_token = '\\' ident

let regexp delim_begin = "\\["
let regexp delim_end = "\\]"

let regexp qkeyword = "'" ( ident | pident ) "'"

let regexp implicit = '?'
let regexp placeholder = '%'
let regexp meta = implicit number

let regexp csymbol = '\'' ident

let regexp begin_group = "@{" | "${"
let regexp end_group = '}'
let regexp wildcard = "$_"
let regexp ast_ident = "@" ident
let regexp ast_csymbol = "@" csymbol
let regexp meta_ident = "$" ident
let regexp meta_anonymous = "$_"

let regexp begincomment = "(**" utf8_blank
let regexp beginnote = "(*"
let regexp endcomment = "*)"
(* let regexp comment_char = [^'*'] | '*'[^')']
let regexp note = "|+" ([^'*'] | "**") comment_char* "+|" *)

let level1_layouts = 
  [ "sub"; "sup";
    "below"; "above";
    "over"; "atop"; "frac";
    "sqrt"; "root"; "mstyle" ; "mpadded"; "maction"

  ]

let level1_keywords =
  [ "hbox"; "hvbox"; "hovbox"; "vbox";
    "break";
    "list0"; "list1"; "sep";
    "opt";
    "term"; "ident"; "number";
  ] @ level1_layouts

let level2_meta_keywords =
  [ "if"; "then"; "elCicNotationParser.se";
    "fold"; "left"; "right"; "rec";
    "fail";
    "default";
    "anonymous"; "ident"; "number"; "term"; "fresh"
  ]

  (* (string, int) Hashtbl.t, with multiple bindings.
   * int is the unicode codepoint *)
let ligatures = Hashtbl.create 23

let _ =
  List.iter
    (fun (ligature, symbol) -> Hashtbl.add ligatures ligature symbol)
    [ ("->", <:unicode<to>>);   ("=>", <:unicode<Rightarrow>>);
      (":=", <:unicode<def>>);
    ]

let regexp nreference =
  "cic:/"                             (* schema *)
  uri_step ('/' uri_step)*            (* path *)
  '.'
  ( "dec"
  | "def" "(" number ")"
  | "fix" "(" number "," number "," number ")"
  | "cfx" "(" number ")"
  | "ind" "(" number "," number "," number ")"
  | "con" "(" number "," number "," number ")") (* ext + reference *)

let error lexbuf msg =
  let begin_cnum, end_cnum = Ulexing.loc lexbuf in
  raise (Error (begin_cnum, end_cnum, msg))
let error_at_end lexbuf msg =
  let begin_cnum, end_cnum = Ulexing.loc lexbuf in
  raise (Error (begin_cnum, end_cnum, msg))

let loc_of_buf lexbuf = 
  HExtlib.floc_of_loc (Ulexing.loc lexbuf)

let return_with_loc token begin_cnum end_cnum =
  let flocation = HExtlib.floc_of_loc (begin_cnum,end_cnum) in
   token, flocation

let return lexbuf token =
  let begin_cnum, end_cnum = Ulexing.loc lexbuf in
    return_with_loc token begin_cnum end_cnum

let return_lexeme lexbuf name = return lexbuf (name, Ulexing.utf8_lexeme lexbuf)

let return_symbol lexbuf s = return lexbuf ("SYMBOL", s)
let return_eoi lexbuf = return lexbuf ("EOI", "")

let remove_quotes s = String.sub s 1 (String.length s - 2)

let mk_lexer token =
  let tok_func stream =
(*     let lexbuf = Ulexing.from_utf8_stream stream in *)
(** XXX Obj.magic rationale.
 * The problem.
 *  camlp5 constraints the tok_func field of Token.glexer to have type:
 *    Stream.t char -> (Stream.t 'te * flocation_function)
 *  In order to use ulex we have (in theory) to instantiate a new lexbuf each
 *  time a char Stream.t is passed, destroying the previous lexbuf which may
 *  have consumed a character from the old stream which is lost forever :-(
 * The "solution".
 *  Instead of passing to camlp5 a char Stream.t we pass a lexbuf, casting it to
 *  char Stream.t with Obj.magic where needed.
 *)
    let lexbuf = Obj.magic stream in
    Token.make_stream_and_location
      (fun () ->
        try
          token lexbuf
        with
        | Ulexing.Error -> error_at_end lexbuf "Unexpected character"
        | Ulexing.InvalidCodepoint p ->
            error_at_end lexbuf (sprintf "Invalid code point: %d" p))
  in
  {
    Token.tok_func = tok_func;
    Token.tok_using = (fun _ -> ());
    Token.tok_removing = (fun _ -> ()); 
    Token.tok_match = Token.default_match;
    Token.tok_text = Token.lexer_text;
    Token.tok_comm = None;
  }

let expand_macro lexbuf =
  let macro =
    Ulexing.utf8_sub_lexeme lexbuf 1 (Ulexing.lexeme_length lexbuf - 1)
  in
  try
    ("SYMBOL", Utf8Macro.expand macro)
  with Utf8Macro.Macro_not_found _ -> 
(* FG: unexpanded TeX macros are terminated by a space for rendering *)     
     "SYMBOL", (Ulexing.utf8_lexeme lexbuf ^ " ")

let remove_quotes s = String.sub s 1 (String.length s - 2)
let remove_left_quote s = String.sub s 1 (String.length s - 1)

let rec level2_pattern_token_group counter buffer =
  lexer
  | end_group -> 
      if (counter > 0) then
	Buffer.add_string buffer (Ulexing.utf8_lexeme lexbuf) ;
      snd (Ulexing.loc lexbuf)
  | begin_group -> 
      Buffer.add_string buffer (Ulexing.utf8_lexeme lexbuf) ;
      ignore (level2_pattern_token_group (counter + 1) buffer lexbuf) ;
      level2_pattern_token_group counter buffer lexbuf
  | _ -> 
      Buffer.add_string buffer (Ulexing.utf8_lexeme lexbuf) ;
      level2_pattern_token_group counter buffer lexbuf

let read_unparsed_group token_name lexbuf =
  let buffer = Buffer.create 16 in
  let begin_cnum, _ = Ulexing.loc lexbuf in
  let end_cnum = level2_pattern_token_group 0 buffer lexbuf in
    return_with_loc (token_name, Buffer.contents buffer) begin_cnum end_cnum

let handle_keywords lexbuf k name = 
  let s = Ulexing.utf8_lexeme lexbuf in
  if k s then
	    return lexbuf ("", s)
	  else
	    return lexbuf (name, s)
;;

let rec level2_meta_token =
  lexer
  | utf8_blank+ -> level2_meta_token lexbuf
  | hreftag -> return lexbuf ("ATAG","")
  | hrefclose -> return lexbuf ("ATAGEND","")
  | ident ->
      handle_keywords lexbuf (fun x -> List.mem x level2_meta_keywords) "IDENT"
  | variable_ident -> return lexbuf ("IDENT", Ulexing.utf8_lexeme lexbuf)
  | pident ->
      handle_keywords lexbuf (fun x -> List.mem x level2_meta_keywords) "PIDENT"
  | "@{" -> read_unparsed_group "UNPARSED_AST" lexbuf
  | ast_ident ->
      return lexbuf ("UNPARSED_AST",
        remove_left_quote (Ulexing.utf8_lexeme lexbuf))
  | ast_csymbol ->
      return lexbuf ("UNPARSED_AST",
        remove_left_quote (Ulexing.utf8_lexeme lexbuf))
  | eof -> return_eoi lexbuf

let rec comment_token acc depth =
  lexer
  | beginnote ->
      let acc = acc ^ Ulexing.utf8_lexeme lexbuf in
      comment_token acc (depth + 1) lexbuf
  | endcomment ->
      let acc = acc ^ Ulexing.utf8_lexeme lexbuf in
      if depth = 0
      then acc
      else comment_token acc (depth - 1) lexbuf
  | _ ->
      let acc = acc ^ Ulexing.utf8_lexeme lexbuf in
      comment_token acc depth lexbuf

  (** @param k continuation to be invoked when no ligature has been found *)
let ligatures_token k =
  lexer
  | ligature ->
      let lexeme = Ulexing.utf8_lexeme lexbuf in
      (match List.rev (Hashtbl.find_all ligatures lexeme) with
      | [] -> (* ligature not found, rollback and try default lexer *)
          Ulexing.rollback lexbuf;
          k lexbuf
      | default_lig :: _ -> (* ligatures found, use the default one *)
          return_symbol lexbuf default_lig)
  | eof -> return_eoi lexbuf
  | _ ->  (* not a ligature, rollback and try default lexer *)
      Ulexing.rollback lexbuf;
      k lexbuf

module LocalizeOD =
  struct
    type t = Stdpp.location
    let compare = Pervasives.compare
  end

let update_table loc desc href loctable =
  if desc <> None || href <> None 
    then 
     (let s,e = HExtlib.loc_of_floc loc in
      prerr_endline (Printf.sprintf "*** [%d,%d] \"%s\",\"%s\""
        s e (so_pp href) (so_pp desc));
      LocalizeEnv.add loc (href,desc) loctable)
    else loctable
;;

let get_hot_spots =
  let rec aux loc1 desc href =
    lexer
    | hreftag -> aux_in_tag (Ulexing.loc lexbuf) None None lexbuf
    | hrefclose -> 
        try
          let loc1 = HExtlib.floc_of_loc (HExtlib.unopt loc1) in
          let loc2 = HExtlib.floc_of_loc (Ulexing.loc lexbuf) in
          (loc1,loc2,href,desc) :: aux None None None lexbuf
        with Failure _ -> aux None None None lexbuf
    | beginnote -> (* FIXME commenti come in smallLexer *) 
        let _comment = comment_token (Ulexing.utf8_lexeme lexbuf) 0 lexbuf in
  (*       let comment =
          Ulexing.utf8_sub_lexeme lexbuf 2 (Ulexing.lexeme_length lexbuf - 4)
        in
        return lexbuf ("NOTE", comment) *)
        ligatures_token (aux desc href) lexbuf
    | begincomment -> return lexbuf ("BEGINCOMMENT","")
    | endcomment -> return lexbuf ("ENDCOMMENT","")
    | eof -> []
    | _ -> aux loc1 desc href lexbuf
  and aux_in_tag loc1 desc href = lexer
    | utf8_blank+ -> aux_in_tag loc1 desc href lexbuf
    | href -> 
        aux_in_tag loc1 desc 
          (Some (Ulexing.utf8_sub_lexeme lexbuf 6 (Ulexing.lexeme_length lexbuf - 7))) 
          lexbuf
    | hreftitle -> 
        aux_in_tag loc1
          (Some (Ulexing.utf8_sub_lexeme lexbuf 7 (Ulexing.lexeme_length lexbuf - 8))) 
          href lexbuf
    | ">" -> 
        let merge (a,b) (c,d) = (a,d) in
        aux (Some (merge loc1 (Ulexing.loc lexbuf))) desc href lexbuf
    | _ -> aux None None None lexbuf
  in aux None None None