(*
    Ocaml - syntax hilighting in LaTeX
    Copyright (C) 2009  BODIN Antoine <antoinexp@gmail.com>

    This program 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 3 of the License, or
    (at your option) any later version.

    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
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*)

let parse f_in f_out =

  let operatortolatex k = match k with
      '*' | '+' | '-' | '/' | '.' -> "{\\color{Yellow}"^(Char.escaped k)^"}"
    | '=' | '<' | '>' -> "{\\color{Blue}"^(Char.escaped k)^"}"
    | '(' | ')' -> "{\\color{Green}"^(Char.escaped k)^"}"
    | '|' -> "{\\color{Red}"^(Char.escaped k)^"}"
    | ':' -> (Char.escaped k)
    | _ -> (Char.escaped k)
  in

  let keywordtolatex k = match k with
      "let" | "rec" -> "{\\color{Blue}"^k^"}"
    | "function" | "fun" | "when" -> "{\\color{Red}"^k^"}"
    | "try" | "match" | "with" -> k
    | "for" | "while" | "do" | "done" -> k
    | "if" | "then" | "else" -> k
    | _ -> print_endline ("["^k^"]"); k
  in

  let codehighlight n =
    output_string f_out ("\\texttt{\n\\begin{tabular}{ c | l }\n1 & ") ;
    let i = ref 1 in
      try while true do
	match input_char f_in with
	    ' ' -> output_string f_out "~"
	  | '\n'-> output_string f_out ("\\\\ \n"^(incr i; string_of_int !i)^" & ")
	  | '}' -> failwith "end of code"
	  | c -> 
	      let rec f () = 
		match input_char f_in with ' ' | '\n' -> "" | c -> (operatortolatex c)^f()
	      in output_string f_out ((keywordtolatex ((operatortolatex c)^(f())))^" ")
      done with _ -> output_string f_out "\\\\ \n \\end{tabular}\n}\n"
  in
    
  let _ = 
    try while true do
      let line = input_line f_in in
	try 
	  let offset = (Str.search_forward (Str.regexp "\\\\ocaml{") line 0) in
	    output_string f_out ((Str.string_before line offset)^"\\emph{");
	    seek_in f_in (pos_in f_in - (String.length line - offset) + 6);
	    try while true do
	      match input_char f_in with '}' -> failwith "end of title" | c -> print_char c; output_char f_out c
	    done with _ -> seek_in f_in (pos_in f_in +1); output_string f_out "}\\\\\n";
	      codehighlight ()
	with Not_found -> output_string f_out (line^"\n")
    done with End_of_file -> ();
  in
    
    close_in f_in; close_out f_out
      


let _ =
  match Sys.argv with
      [|_;a;b|] -> parse (open_in_bin a) (open_out_bin b)
    | [|_;a|] -> parse (open_in_bin a) (open_out_bin (a^".otex"))
    | _ -> print_endline "use : ocaml2latex.ml [file_to_parse] ~[output]"