(* 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/.
 *)

(*  AUTOR: Ferruccio Guidi <fguidi@cs.unibo.it>
 *)

module M = MathQL
module C = MQIConn
module U = MQIUtil
module A = MQIMap

let not_supported s = 
   raise (Failure ("MQIProperty: feature not supported: " ^ s)) 

(* debugging  ***************************************************************)

let pg_print l =
   let rec pg_record = function 
      | []           -> prerr_newline ()
      | head :: tail -> prerr_string (head ^ " "); pg_record tail
   in
   List.iter pg_record l

let cl_print l =  
   let c_print (b, p, v) =
      prerr_string (if b then "match " else "in ");
      List.iter (fun x -> prerr_string ("/" ^ x)) p;
      prerr_newline ();
      List.iter prerr_endline v
   in
   List.iter c_print l

(* Common functions  ********************************************************)

let pg_result distinct subj el res =
  let compose = if distinct then List.map else fun f -> U.mql_iter (fun x -> [f x]) in 
  let get_name = function (p, None) -> p | (_, Some p) -> p in
  let names = List.map get_name el in
  let mk_grp l = 
     let grp = U.mql_iter2 (fun p s -> [(p, [s])]) names l in 
     if grp = [] then [] else [grp]
  in
  let mk_avs l =
     if subj = "" then ("", mk_grp l) else (List.hd l, mk_grp (List.tl l))
  in
  compose mk_avs res

let get_table h mc ct cfl el =
   let aux_c ts (_, p, _) = A.refine_tables ts (C.tables h p) in
   let aux_e ts (p, _) = A.refine_tables ts (C.tables h p) in
   let fst = C.tables h mc in
   let snd = List.fold_left aux_c fst (ct @ (List.concat cfl)) in
   let trd = List.fold_left aux_e snd el in
   A.default_table trd

let exec_single h mc ct cfl el table =
   let conv p = C.field h p table in
   let first = conv mc in
   let mk_con l = List.map (fun (pat, p, v) -> (pat, conv p, v)) l in
   let cons_true = mk_con ct in 
   let cons_false = List.map mk_con cfl in
   let other_cols = List.map (fun (p, _) -> conv p) el in 
   let cols = if first = "" then other_cols else first :: other_cols in
   let out q = if C.set h C.Queries then C.log h (q ^ "\n") in
   let r = C.exec h out (C.resolve h table) cols cons_true cons_false in
   pg_result false first el r
   
let deadline = 100

let exec h refine mc ct cfl el =
   if refine <> M.RefineExact then not_supported "exec";   
   let table = get_table h mc ct cfl el in
   let rec exec_aux ct = match ct with 
      | (pat, p, v) :: tail when List.length v > deadline ->
         let single s = exec_aux ((pat, p, [s]) :: tail) in
	 U.mql_iter single v
      | _                                                 ->
         exec_single h mc ct cfl el table
   in exec_aux ct