(* 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/.
 *)

(*
 * implementazione del'interprete MathQL
 *)

(*
(* FG: ROBA VECCHIA DA BUTTARE (tranne apertura e chiusura database *)

open MathQL;;
open Eval;;
open Utility;;

open Pattern;;*)
open Dbconn;;
open Union;;
open Intersect;;
open Meet;;
open Sub;;
open Context;;
open Diff;;
open Relation;;
(*open Sortedby;;
open Use;;
open Select;;
open Letin;;
open Mathql_semantics;;



let prop_pool = ref None;;

let fi_to_string fi =
 match fi with
    (None, _)   ->
     ""
 |  (Some i, y) ->
     "#xpointer(1/"       ^
     string_of_int i      ^
     (
      match y with
         None   ->
          ""
      |  Some j ->
          "/" ^ (string_of_int j)
     )                    ^
     ")"
;;

let see_prop_pool () =
 let _ = print_endline "eccomi" in
 List.iter
  (fun elem -> print_endline (fst elem ^ ": " ^ snd elem))
  (match !prop_pool with Some l -> l | _ -> print_endline "ciao"; assert false)
;;



let get_prop_id prop =
 if prop="refObj" then "F"
 else if prop="backPointer" then "B"
 else List.assoc prop (match !prop_pool with Some l -> l | _ -> assert false)
;;

(* execute_ex env q                                                   *)
(*  [env] is the attributed uri environment in which the query [q]    *)
(*        must be evaluated                                           *)
(*  [q]   is the query to evaluate                                    *)
(*  It returns a [Mathql_semantics.result]                            *)
let rec execute_ex env =
 function
    MQSelect (apvar, alist, abool) ->
     select_ex env apvar (execute_ex env alist) abool
 |  MQUsedBy (alist, asvar) ->
     use_ex (execute_ex env alist) asvar (get_prop_id "refObj")      (* "F" (*"refObj"*) *)
 |  MQUse (alist, asvar) ->
     use_ex (execute_ex env alist) asvar (get_prop_id "backPointer") (* "B" (*"backPointer"*) *)
 |  MQPattern (apreamble, apattern, afragid) ->
     pattern_ex (apreamble, apattern, afragid)
 |  MQUnion (l1, l2) ->
     union_ex (execute_ex env l1) (execute_ex env l2)
 |  MQDiff (l1, l2) ->
     diff_ex (execute_ex env l1) (execute_ex env l2)
 |  MQSortedBy (l, o, f) ->
     sortedby_ex (execute_ex env l) o f
 |  MQIntersect (l1, l2) ->
     intersect_ex (execute_ex env l1) (execute_ex env l2)
 |  MQListRVar rvar -> [List.assoc rvar env]
 |  MQLetIn (lvar, l1, l2) ->
     let t = Unix.time () in
      let res =
       (*CSC: The interesting code *)
       let _ = letin_ex lvar (execute_ex env l1) in
        execute_ex env l2
       (*CSC: end of the interesting code *)
      in
       letdispose ();
       print_string ("LETIN = " ^ string_of_int (List.length res) ^ ": ") ;
       print_endline (string_of_float (Unix.time () -. t) ^ "s") ;
       flush stdout ;
       res
 |  MQListLVar lvar ->
     letref_ex lvar
 |  MQReference l ->
     let rec build_result = function
       | [] -> []
       | s :: tail -> 
	 {uri = s ; attributes = [] ; extra = ""} :: build_result tail
     in build_result (List.sort compare l)
;;

(* Let's initialize the execute in Select, creating a cyclical recursion *)
Select.execute := execute_ex;;

(*
 * converte il risultato interno di una query (uri + contesto)
 * in un risultato di sole uri
 *
 * parametri:
 * l: string list list;
 *
 * output: mqresult;
 *
 * note:
 * il tipo del risultato mantenuto internamente e' diverso dal tipo di risultato
 * restituito in output poiche', mentre chi effettua le query vuole come risultato
 * solo le eventuali uri che soddisfano le query stesse, internamente ad una uri
 * sono associati anche i valori delle variabili che ancora non sono state valutate
 * perche', ad esempio, si trovano in altri rami dell'albero.
 *
 * Esempio:
 * SELECT x IN USE PATTERN "cic:/**.con" POSITION $a WHERE $a IS MainConclusion
 * L'albero corrispondente a questa query e':
 *
 *                  SELECT
 *                /   |    \
 *               x   USE    IS
 *                  /   \    /\
 *           PATTERN    $a  $a MainConclusion
 *
 * Nel momento in cui si esegue il ramo USE non sono noti i vincoli sullla variabile $a
 * percui e' necessario considerare, oltre alle uri, i valori della variabile per i quali
 * la uri puo' far parte del risultato.
 *)
let xres_to_res l =
 MQRefs (List.map (function {Mathql_semantics.uri = uri} -> uri) l)
(*
 let tmp = List.map (function {Mathql_semantics.uri = uri} -> uri) l in
  MQRefs
   (List.map
    (function l ->
      (*let _ = print_endline ("DEBUG: (mqint.ml: xres_to_res)" ^ l) in*)
      match Str.split (Str.regexp ":\|#\|/\|(\|)") l with
         hd::""::tl -> (
          match List.rev tl with
             n::"1"::"xpointer"::tail    ->
              (
               Some hd,
               List.fold_left
                (fun par t ->
                 match par with
                    [] -> [MQBC t] 
                 |  _  -> (MQBC t) :: MQBD :: par
                )
                []
                tail, 
               [MQFC (int_of_string n)]
              )
          |  n::m::"1"::"xpointer"::tail ->
              (
               Some hd,
               List.fold_left
                (fun par t ->
                 match par with
                    [] -> [MQBC t] 
                 |  _  -> (MQBC t) :: MQBD :: par
                )
                []
                tail,
               [MQFC (int_of_string m); MQFC (int_of_string n)]
              )
          |  tail                          ->
              (
               Some hd,
               List.fold_left
                (fun par t ->
                 match par with
                    [] -> [MQBC t] 
                 |  _  -> (MQBC t) :: MQBD :: par
                )
                []
                tail, 
               []
              )
      )  
       | _ -> assert false
    )
    tmp
   )
*)
;;


(*
 * 
 *)
let execute q =
 match q with
    MQList qq -> xres_to_res (execute_ex [] qq)
;;

let prop_pool = ref None;;

*****************************************************************************)

let init () = Dbconn.init () 
(*
   let c = pgc () in
   let res = 
      c#exec "select name,id from property where ns_id in (select id from namespace where url='http://www.cs.unibo.it/helm/schemas/mattone.rdf#')"
   in
   prop_pool := Some
     (
      List.map
       (function
           a::b::_ -> (a, b)
         | _       -> print_endline "no"; assert false
       )
       res#get_list
     )
*) 

let close () = Dbconn.close ()

let check () = Dbconn.pgc ()

exception BooleExpTrue

(* valuta una MathQL.set_exp e ritorna un MathQL.resource_set *)

let rec exec_set_exp c = function
   |MathQL.SVar svar -> List.assoc svar c.svars
   |MathQL.RVar rvar -> [List.assoc rvar c.rvars]  
   | MathQL.Ref vexp -> List.map (fun s -> (s,[])) (exec_val_exp c vexp)
   | MathQL.Intersect (sexp1, sexp2) -> intersect_ex (exec_set_exp c sexp1) (exec_set_exp c sexp2)    
   | MathQL.Union (sexp1, sexp2) -> union_ex (exec_set_exp c sexp1) (exec_set_exp c sexp2)
   | MathQL.LetSVar (svar, sexp1, sexp2) -> let _ = (svar, (exec_set_exp c sexp1)):: (List.remove_assoc svar c.svars) 
   					in (exec_set_exp c sexp2)
   | MathQL.LetVVar (vvar, vexp, sexp) -> let _ = (vvar, (exec_val_exp c vexp)):: (List.remove_assoc vvar c.vvars)
   					in (exec_set_exp c sexp)
   | MathQL.Relation (rop, path, sexp, attl) -> relation_ex rop path (exec_set_exp c sexp) attl
   | MathQL.Select (rvar, sexp, bexp) -> let rset = (exec_set_exp c sexp) in
                                          let rec select_ex rset =
					    match rset with 
						      [] -> []
					    | r::tl -> let c1 = upd_rvars c ((rvar,r)::c.rvars) in                      
	                                       if (exec_boole_exp c1 bexp) then r::(select_ex tl)
   		                               else select_ex tl
                                          in select_ex rset
					               
   					   			                   
   
   | MathQL.Diff (sexp1, sexp2) -> diff_ex (exec_set_exp c sexp1) (exec_set_exp c sexp2)
   | _ -> assert false
   
(* valuta una MathQL.boole_exp e ritorna un boole *)

and exec_boole_exp c = function
   | MathQL.False      -> false
   | MathQL.True       -> true
   | MathQL.Not x      -> not (exec_boole_exp c x)
   | MathQL.And (x, y) -> (exec_boole_exp c x) && (exec_boole_exp c y)
   | MathQL.Or (x, y)  -> (exec_boole_exp c x) || (exec_boole_exp c y)
   | MathQL.Sub (vexp1, vexp2) -> sub_ex (exec_val_exp c vexp1) (exec_val_exp c vexp2)
   | MathQL.Meet (vexp1, vexp2) -> meet_ex (exec_val_exp c vexp1) (exec_val_exp c vexp2)
   | MathQL.Eq (vexp1, vexp2) -> (exec_val_exp c vexp1) = (exec_val_exp c vexp2)
   | MathQL.Ex l bexp -> 
   	if l = [] then (exec_boole_exp c bexp)
   	else
   	  let latt = List.map (fun uri -> 
                                       let (r,attl) = List.assoc uri c.rvars 
				       in (uri,attl)) l (*latt = l + attributi*)
	  in
	   try
	     let rec prod c = function
	       	[] -> if (exec_boole_exp c bexp) then raise BooleExpTrue 
	      | (uri,attl)::tail1 -> let rec sub_prod attl =
			     	      match attl with
(*per ogni el. di attl  *)		[] -> () 
(*devo andare in ric. su tail1*)      | att::tail2 -> let c1 = upd_groups c ((uri,att)::c.groups) in             
						       prod c1 tail1; sub_prod tail2 
				     in	      
			              sub_prod attl 
   	     in
	      prod c latt; false
	   with BooleExpTrue -> true  
   | _ -> assert false    

(* valuta una MathQL.val_exp e ritorna un MathQL.value *)

and exec_val_exp c = function
   | MathQL.Const x -> let
   ol = List.sort compare x in 
   			let rec edup = function
			
			   [] -> [] 
			 | s::tl -> if tl <> [] then  
			                         if s = (List.hd tl) then edup tl
			                         else s::(edup tl)
				    else s::[]
	                in
			 edup ol
   | MathQL.Record (rvar, vvar) -> List.assoc vvar (List.assoc rvar c.groups) 
				  
   | MathQL.VVar s -> List.assoc s c.vvars				  
   | MathQL.RefOf sexp -> List.map (fun (s,_) -> s) (exec_set_exp c sexp)
   
   | _ -> assert false


(* valuta una MathQL.set_exp nel contesto vuoto e ritorna un MathQL.resource_set *)

and execute x =
   exec_set_exp {svars = []; rvars = []; groups = []; vvars = []} x 




(*
 * chiusura della connessione al database
  *)
  let close () = Dbconn.close ();;