(***********************************************************************)
(*                                                                     *)
(*                               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.                                                        *)
(*                                                                     *)
(***********************************************************************)

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
     Html.trace (T.preorder tree node) i
       "node: %i<br/>%s<br/>sat: %a<br/>unsat: %a<br/>todo: %around: %i<br/>"
       (T.preorder tree node)
       msg
       StateSet.print config.Ata.sat
       StateSet.print config.Ata.unsat
       (Ata.TransList.print ~sep:"<br/>") config.Ata.todo i



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



  let top_down_run auto tree node run =
    let module Array =
    struct
      include Array
      let get a i =
        if i < 0 then Ata.dummy_config else get a i
      let unsafe_get a i =
        if i < 0 then Ata.dummy_config else unsafe_get a i
    end
    in
    let cache = run.config in
    let unstable = run.unstable in
    let _i = run.pass in
    let rec loop node =
      let node_id = T.preorder tree node in
      if node == T.nil || not (Bitvector.get unstable node_id) then false else begin
        let parent = T.parent tree node in
        let fc = T.first_child tree node in
        let fc_id = T.preorder tree fc in
        let ns = T.next_sibling tree node in
        let ns_id = T.preorder tree ns in
        let tag = T.tag tree node in
        let config0 =
          let c = cache.(node_id) in
          if c == Ata.dummy_config 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 = cache.(T.preorder tree parent) in
        let fcs = cache.(fc_id) in
        let nss = cache.(ns_id) in
        let config1 = Ata.eval_trans auto fcs nss ps config0 in

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

        if config0 != config1 then cache.(node_id) <- config1;
        let unstable_left = loop fc in
        let fcs1 = cache.(fc_id) 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 cache.(node_id) <- config2;
        let unstable_right = loop ns in
        let nss1 = cache.(ns_id) 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 cache.(node_id) <- config3;
        let unstable_self =
          unstable_left
          || unstable_right
          || Ata.(TransList.nil != config3.Config.node.todo)
        in
        Bitvector.unsafe_set unstable node_id unstable_self;
        TRACE((if not unstable_self then
            Html.finalize_node
              node_id
              _i
              Ata.(StateSet.intersect config3.Config.node.sat auto.selection_states)));
        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 Ata.(
          StateSet.intersect
            cache.(T.preorder tree node).Config.node.sat
            auto.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 len = T.size tree in
    let run = { config = Array.create len Ata.dummy_config;
                unstable = Bitvector.create ~init:true len;
                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