(*let nparamod metasenv subst context t table =
  prerr_endline "========================================";
  let module C = struct
    let metasenv = metasenv
    let subst = subst
    let context = context
  end
  in
  let module B = NCicBlob.NCicBlob(C) in
  let module Pp = Pp.Pp (B) in
  let module FU = FoUnif.Founif(B) in
  let module IDX = Index.Index(B) in
  let module Sup = Superposition.Superposition(B) in
  let module Utils = FoUtils.Utils(B) in*)
(*
  let test_unification _ = function
    | Terms.Node [_; _; lhs; rhs] ->
	prerr_endline "Unification test :";
	prerr_endline (Pp.pp_foterm lhs);
	prerr_endline (Pp.pp_foterm rhs);
        FU.unification [] [] lhs rhs
    | _ -> assert false
  in
  let subst,vars = test_unification [] res in
    prerr_endline "Result :";
    prerr_endline (Pp.pp_foterm res);
    prerr_endline "Substitution :";
    prerr_endline (Pp.pp_substitution subst)
*)
(*

  let mk_clause maxvar t =
    let ty = B.embed t in
    let proof = B.embed (NCic.Rel ~-1) in
    Utils.mk_unit_clause maxvar ty proof 
  in
  let clause, maxvar = mk_clause 0 t in
  prerr_endline "Input clause :";
  prerr_endline (Pp.pp_unit_clause clause);
  let bag = Utils.empty_bag in
  let active_clauses, maxvar = 
    List.fold_left
      (fun (cl,maxvar) t -> 
         let c, m = mk_clause maxvar t in
         c::cl, m)
      ([],maxvar) table 
  in
  let table =  
    List.fold_left IDX.index_unit_clause IDX.DT.empty active_clauses
  in
  prerr_endline "Active table:";
  List.iter (fun uc -> prerr_endline (Pp.pp_unit_clause uc)) active_clauses;
  let bag, maxvar, _, newclauses = 
    Sup.infer_right bag maxvar clause (active_clauses, table)
  in
  prerr_endline "Output clauses :";
  List.iter (fun c -> prerr_endline (Pp.pp_unit_clause c)) newclauses;
  (* prerr_endline "Proofs: ";
  prerr_endline (Pp.pp_bag bag); *)
  prerr_endline "========================================";
;;
*)
let debug s =
  prerr_endline s
;;

let nparamod metasenv subst context t table =
  prerr_endline "========================================";
  let module C = struct
    let metasenv = metasenv
    let subst = subst
    let context = context
  end
  in
  let module B = NCicBlob.NCicBlob(C) in
  let module Pp = Pp.Pp (B) in
  let module FU = FoUnif.Founif(B) in
  let module IDX = Index.Index(B) in
  let module Sup = Superposition.Superposition(B) in
  let module Utils = FoUtils.Utils(B) in
    
  let module OrderedPassives =
      struct
	type t = B.t Terms.passive_clause
	    
	let compare = Utils.compare_passive_clauses
      end
  in
  let module PassiveSet = Set.Make(OrderedPassives)
  in
  let add_passive_clause passives cl =
    PassiveSet.add (Utils.mk_passive_clause cl) passives
  in
    (* TODO : fairness condition *)
  let select passives =
    if PassiveSet.is_empty passives then None
    else let cl = PassiveSet.min_elt passives in
      Some (snd cl,PassiveSet.remove cl passives)
  in
  let rec given_clause bag maxvar actives passives g_actives g_passives =
    
    (* keep goals demodulated w.r.t. actives and check if solved *)
    (* we may move this at the end of infer_right and simplify with
     * just new_clauses *) 
    let bag, g_actives = 
      List.fold_left 
        (fun (bag,acc) c -> 
           let bag, c = Sup.backward_simplify maxvar (snd actives) bag c in
             bag, c::acc) 
        (bag,[]) g_actives 
    in
      
      (* backward step : superposition left, simplifications on goals *)
      debug "Backward infer step...";
      let bag, maxvar, g_actives, g_passives =
	match select g_passives with
      | None -> bag, maxvar, g_actives, g_passives
      | Some (g_current, g_passives) -> 
	  debug ("Selected goal : " ^ Pp.pp_unit_clause g_current);
          let bag, g_current = 
            Sup.backward_simplify maxvar (snd actives) bag g_current
          in
          let bag, maxvar, new_goals = 
            Sup.infer_left bag maxvar g_current actives 
          in
	  let new_goals = List.fold_left add_passive_clause
	    PassiveSet.empty new_goals
	  in
          bag, maxvar, g_current::g_actives,
	  (PassiveSet.union new_goals g_passives)
    in
      prerr_endline
	(Printf.sprintf "Number of active goals : %d"
	   (List.length g_actives));
      prerr_endline
	(Printf.sprintf "Number of passive goals : %d"
	   (PassiveSet.cardinal g_passives));
  
      (* forward step *)
 
      (* e = select P           *
       * e' = demod A e         *
       * A' = demod [e'] A      *
       * A'' = A' + e'          *
       * e'' = fresh e'         *
       * new = supright e'' A'' *
       * new'= demod A'' new    *
       * P' = P + new'          *)
      debug "Forward infer step...";
    let bag, maxvar, actives, passives, g_passives =
      match select passives with
      | None -> bag, maxvar, actives, passives, g_passives
      | Some (current, passives) -> 
	  debug ("Selected fact : " ^ Pp.pp_unit_clause current);
          match Sup.forward_simplify (snd actives) bag current with
          | None -> debug ("Discarded fact");
	      bag, maxvar, actives, passives, g_passives
          | Some (bag, current) ->
	      debug ("Fact after simplification :" ^ Pp.pp_unit_clause current);
              let bag, maxvar, actives, new_clauses = 
                Sup.infer_right bag maxvar current actives 
              in
	      let ctable = IDX.index_unit_clause IDX.DT.empty current in
	      let bag, maxvar, new_goals = 
		List.fold_left 
		  (fun (bag,m,acc) g -> 
		     let bag, m, ng = Sup.infer_left bag maxvar g
		       ([current],ctable) in
		       bag,m,ng@acc) 
		  (bag,maxvar,[]) g_actives 
	      in
	      let new_clauses = List.fold_left add_passive_clause
		PassiveSet.empty new_clauses in
	      let new_goals = List.fold_left add_passive_clause
		PassiveSet.empty new_goals in
		bag, maxvar, actives,
	      PassiveSet.union new_clauses passives,
	      PassiveSet.union new_goals g_passives
    in
      prerr_endline
	(Printf.sprintf "Number of actives : %d" (List.length (fst actives)));
      prerr_endline
	(Printf.sprintf "Number of passives : %d"
	   (PassiveSet.cardinal passives));
      given_clause bag maxvar actives passives g_actives g_passives
  in

  let mk_clause bag maxvar (t,ty) =
    let (proof,ty) = B.saturate t ty in
    let c, maxvar = Utils.mk_unit_clause maxvar ty proof in
    let bag, c = Utils.add_to_bag bag c in
    bag, maxvar, c
  in
  let bag, maxvar, goal = mk_clause Terms.M.empty 0 t in
  let g_actives = [] in
  let g_passives = PassiveSet.singleton (Utils.mk_passive_clause goal) in
  let passives, bag, maxvar = 
    List.fold_left
      (fun (cl, bag, maxvar) t -> 
         let bag, maxvar, c = mk_clause bag maxvar t in
         (add_passive_clause cl c), bag, maxvar)
      (PassiveSet.empty, bag, maxvar) table 
  in
  let actives = [], IDX.DT.empty in
  try given_clause bag maxvar actives passives g_actives g_passives
  with Sup.Success (bag, _, mp) ->
    prerr_endline "YES!";
    prerr_endline "Meeting point :"; prerr_endline (Pp.pp_unit_clause mp);
    (* prerr_endline "Bag :"; prerr_endline (Pp.pp_bag bag) *)
;;