(* Copyright (C) 2000, 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://cs.unibo.it/helm/.
 *)

exception XsltProcessorCouldNotSend;;
exception XsltProcessorCouldNotReceive;;

let portserver = 12345;;
let portclient = 12346;;
let time_to_wait = 10;;

let rec process uri usecache mode =
 let module U = Unix in
  let uri = UriManager.string_of_uri uri in
  let pid = string_of_int (U.getpid ())
  and filename' =
   let uri' = Str.replace_first (Str.regexp ".*:") "" uri in
    Str.global_replace (Str.regexp "/") "_"
     (Str.global_replace (Str.regexp "_") "__" uri')
  in let tmpfile = "/tmp/helm_" ^ filename' ^ "_" ^ pid in
   (* test if the cache can be used *)
   let tmp_file_exists = Sys.file_exists tmpfile in
    if usecache && tmp_file_exists then
     tmpfile
    else
     let url = Configuration.getter_url ^ uri in
      (* purge the cache if asked to *)
      if not usecache && tmp_file_exists then
        Sys.remove tmpfile ;
      (* let string_to_send = mode ^ " " ^ url ^ " " ^ tmpfile in *)
      let string_to_send = "apply " ^ url ^ " " ^ tmpfile ^
       match mode with
          "cic" -> " C1 C2"
	| "theory" -> " T1 T2"
      in
      (* next function is for looping in case the server is not responding *)
       let socketserver = U.socket U.PF_INET U.SOCK_DGRAM 0 in
        let rec contact_server () =
         let n =
	  Printf.printf "sending %s to server...\n" string_to_send;
	  flush stdout;
          U.sendto socketserver string_to_send 0 (String.length string_to_send)
           [] (U.ADDR_INET(U.inet_addr_any,portserver))
         in
          if n = -1 then raise XsltProcessorCouldNotSend ;
          let process_signal _ = () in
          Sys.set_signal Sys.sigalrm (Sys.Signal_handle process_signal) ;
          (* if the server does not respond, repeat the query *)
          ignore (U.alarm time_to_wait) ;
          try
           if U.recv socketserver "" 0 0 [] = -1 then
            raise XsltProcessorCouldNotReceive ;
           ignore (U.alarm 0) ; (* stop the bomb *)
           Sys.set_signal Sys.sigalrm Sys.Signal_default ;
           U.close socketserver ;
           tmpfile
          with
           U.Unix_error(_,"recv",_) ->
            print_endline "Xaland server not responding. Retrying..." ;
            flush stdout;
            contact_server ()
        in
	 contact_server ()
;;