(***********************************************************************)
(*                                                                     *)
(*                               TAToo                                 *)
(*                                                                     *)
(*                     Kim Nguyen, LRI UMR8623                         *)
(*                   Université Paris-Sud & CNRS                       *)
(*                                                                     *)
(*  Copyright 2010-2013 Université Paris-Sud and Centre National de la *)
(*  Recherche Scientifique. All rights reserved.  This file is         *)
(*  distributed under the terms of the GNU Lesser General Public       *)
(*  License, with the special exception on linking described in file   *)
(*  ../LICENSE.                                                        *)
(*                                                                     *)
(***********************************************************************)

(*
  Time-stamp: <Last modified on 2013-04-25 15:12:45 CEST by Kim Nguyen>
*)

INCLUDE "utils.ml"
open Format

module Make (T : Tree.S) :
  sig
    val eval : Ata.t -> T.t -> T.node -> T.node list
  end
 = struct


IFDEF HTMLTRACE
  THEN
DEFINE TRACE(e) = (e)
  ELSE
DEFINE TRACE(e) = ()
END

   let html tree node i config msg =
     let config = config.Ata.Config.node in
     let oldi = config.Ata.round in
     Html.trace (T.preorder tree node) i oldi
       "node: %i<br/>%s<br/>sat: %a<br/>unsat: %a<br/>todo: %around: %i<br/>"
       ((T.preorder tree node):>int)
       msg
       StateSet.print config.Ata.sat
       StateSet.print config.Ata.unsat
       (Ata.TransList.print ~sep:"<br/>") config.Ata.todo oldi


  let get c t n = Cache.N1.find c (T.preorder t n)

  let set c t n v i =
    v.Ata.Config.node.Ata.round <- i;
    Cache.N1.add c (T.preorder t n) v


  type run = { config : Ata.Config.t Cache.N1.t;
               unstable : Bitvector.t;
               mutable redo : bool;
               mutable pass : int;
             }


  let top_down_run auto tree node run =
    let cache = run.config in
    let unstable = run.unstable in
    let _i = run.pass in
    let rec loop node =
      if node == T.nil then false else begin
        let parent = T.parent tree node in
        let fc = T.first_child tree node in
        let ns = T.next_sibling tree node in
        let tag = T.tag tree node in
        let config0 =
          let c = get cache tree node in
          if c == Cache.N1.dummy cache then
            Ata.Config.make
              { c.Ata.Config.node with
                Ata.todo = Ata.get_trans auto tag auto.Ata.states;
                summary = Ata.node_summary
                  (node == T.first_child tree parent) (* is_left *)
                  (node == T.next_sibling tree parent) (* is_right *)
                  (fc != T.nil) (* has_left *)
                  (ns != T.nil) (* has_right *)
                  (T.kind tree node) (* kind *)
              }
          else c
        in

        TRACE(html tree node _i config0 "Entering node");

        let ps = get cache tree parent in
        let fcs = get cache tree fc in
        let nss = get cache tree ns in
        let config1 = Ata.eval_trans auto fcs nss ps config0 in

        TRACE(html tree node _i config1 "Updating transitions");

        if config0 != config1 then set cache tree node config1 _i;
        let old_unstable_left = Bitvector.unsafe_get unstable (T.preorder tree fc) in
        let unstable_left = old_unstable_left && loop fc in
        let fcs1 = get cache tree fc in
        let config2 = Ata.eval_trans auto fcs1 nss ps config1 in

        TRACE(html tree node _i config2 "Updating transitions (after first-child)");

        if config1 != config2 then set cache tree node config2 _i;
        let old_unstable_right = Bitvector.unsafe_get unstable (T.preorder tree ns) in
        let unstable_right = old_unstable_right && loop ns in
        let nss1 = get cache tree ns in
        let config3 = Ata.eval_trans auto fcs1 nss1 ps config2 in

        TRACE(html tree node _i config3 "Updating transitions (after next-sibling)");

        if config2 != config3 then set cache tree node config3 _i;
        let unstable_self =
          unstable_left
          || unstable_right
          || Ata.(TransList.nil != config3.Config.node.todo)
        in
        Bitvector.unsafe_set unstable (T.preorder tree node) unstable_self;
        unstable_self
      end
    in
    loop node

  let get_results auto tree node cache =
    let rec loop node acc =
      if node == T.nil then acc
      else
        let acc0 = loop (T.next_sibling tree node) acc in
        let acc1 = loop (T.first_child tree node) acc0 in

        if StateSet.intersect
          (get cache tree node).Ata.Config.node.Ata.sat
          auto.Ata.selection_states then node::acc1
        else acc1
    in
    loop node []


  let stats run =
    let count = ref 0 in
    let len = Bitvector.length run.unstable in
    for i = 0 to len - 1 do
      if not (Bitvector.unsafe_get run.unstable i) then
        incr count
    done;
    Logger.msg `STATS
      "%i nodes over %i were skipped in iteration %i (%.2f %%), redo is: %b"
      !count len run.pass (100. *. (float !count /. float len))
      run.redo


  let eval auto tree node =
    let run = { config = Cache.N1.create
        Ata.(Config.make { sat = StateSet.empty;
                           unsat = StateSet.empty;
                           todo = TransList.nil;
                           summary = dummy_summary;
                           round = ~-1
                         });
                unstable = Bitvector.create ~init:true (T.size tree);
                redo = true;
                pass = 0
              }
    in
    while run.redo do
      run.redo <- false;
      Ata.reset auto; (* prevents the .cache2 and .cache4 memoization tables from growing too much *)
      run.redo <- top_down_run auto tree node run;
      stats run;
      run.pass <- run.pass + 1;
    done;
    at_exit (fun () -> Logger.msg `STATS "%i iterations" run.pass);
    at_exit (fun () -> stats run);
    let r = get_results auto tree node run.config in

    TRACE(Html.gen_trace (module T : Tree.S with type t = T.t) (tree));

    r

end