(* 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://www.cs.unibo.it/helm/.
 *)


(*
 * implementazione del comando Relation 
 *)




open Union;;
open Dbconn;;
open Utility;;




let get_prop_id propl =
  let prop = fst propl in
  if prop="refObj" then "F"
  else if prop="backPointer" then "B"
       else assert false
;;


let relation_ex inv rop path rset attl =
  let usek = get_prop_id path in
  let vvar = if attl = [] then "position"
             else List.hd attl
  in	   
  let c = pgc () in
  let rset_list =  (* lista di singoletti:resource_set di un elemento *)
  (List.fold_left (fun acc (uri,l) ->
    let tv = pgresult_to_string (c#exec ("select id from registry where uri='" ^ uri ^ "'")) in
    let qq = "select uri, position from t" ^ tv ^ " where prop_id='" ^ usek ^ "' order by uri asc" in
    let res = c#exec qq in
    (List.map
    (function 
         [uri;context] -> [(uri,[[((vvar, []),[context])]])]
       | _ -> assert false ) 
	res#get_list) @ acc
	          )		      
        [] rset			      
  )
  in                
  let rec edup = function
      [] -> []
    | rs1::tl -> union_ex rs1 (edup tl) 
  in 
  edup rset_list 
;;



(**** IMPLEMENTAZIONE DELLA RELATION PER GALAX ****)


(* trasforma un uri in un filename *)
let tofname uri =
    if String.contains uri ':' then
      (let len = String.length uri in
       let scuri = String.sub uri 4 (len-4) in (*tolgo cic:*)
       if String.contains scuri '#' then
         (let pos = String.index scuri '#' in
          let s1 = Str.string_before scuri pos in
          let xp = Str.string_after scuri pos in
          let xp = Str.global_replace (Str.regexp "#xpointer(1") "" xp in
          let xp = Str.global_replace (Str.regexp "\/") "," xp in
          let xp = Str.global_replace (Str.regexp ")") "" xp in
          let fname = (s1 ^ xp) in
          fname)
       else
         scuri)
    else uri


(* prende una lista di uri (contenente alternativamente uri e pos) e costruisce una lista di resource *)
let rec rsetl uril vvar = 
    match uril with                   
    | uri::tl -> let scuri = (*tofname*) uri in
                   [(scuri, [[((vvar, []), [(List.hd tl)])]])]::(rsetl (List.tl tl) vvar)
    | [] -> [] 


(* prende una resource e una vvar e  restituisce la lista delle resource in relazione (refObj o backPointer in base al parametro "path") con tale resource e associa alla proprieta' il nome della vvar contenuto in "attl" *)
let muse path attl r =
        let vvar = if attl = [] then "position"
                   else List.hd attl
        in	    
        let uri = fst r in
	let furi = tofname uri in
        let dtag = fst path in
        let dir =
          match dtag with
              "refObj" -> "/projects/helm/metadata/create4/forward"
            | _ -> "/projects/helm/metadata/create4/backward"
        in 
        let xq ="namespace h=\"http://www.cs.unibo.it/helm/schemas/mattone.rdf#\"
                namespace rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\"
                for $i in document(" ^ "\"" ^ dir ^ furi ^ ".xml" ^ "\"" ^
                ")/rdf:RDF/h:Object/h:" ^ dtag ^ "/h:Occurrence
                return ($i/h:occurrence, $i/h:position)"
        
        in
        let uril = Toputils.eval_query_string xq in (* e' una lista di liste di stringhe*)
        let  hd_uril = List.hd uril in(*prendo la testa che contiene altern. lista di uri e pos. *)
        let rset_list = rsetl hd_uril vvar in (* da hd_uril costruisco una lista di resource_set(singoletti)*)
        let rec edup = function
	    [] -> []
	  | rs1::tl -> union_ex rs1 (edup tl)
        in
	edup rset_list
		      
            


(* prende un resource_set, una vvar (primo el. di attl) a cui associare la posizione, e la relazione (refObj o backPointer) e per ogni resource chiama la muse 
NOTA: "rop" per ora non viene usato perche' vale sempre "ExactOp" *)
let relation_galax_ex inv rop path rset attl =
    List.stable_sort (fun (uri1,l1) (uri2,l2) -> compare uri1 uri2) (List.concat (List.map (muse path attl) rset))