(***********************************************************************)
(*                                                                     *)
(*                               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
open Misc

module Make (T : Tree.S) =
 struct

   module NodeSummary =
   struct
     (* Pack into an integer the result of the is_* and has_ predicates
        for a given node *)
     type t = int
     let dummy = -1
    (*
      4444444444443210
      4 -> kind
      3 -> is_left
      2 -> is_right
      1 -> has_left
      0 -> has_right
    *)

     let has_right (s : t) : bool =
       Obj.magic (s land 1)

     let has_left (s : t) : bool =
       Obj.magic ((s lsr 1) land 1)

     let is_right (s : t) : bool =
       Obj.magic ((s lsr 2) land 1)

     let is_left (s : t) : bool =
       Obj.magic ((s lsr 3) land 1)

     let kind (s : t) : Tree.NodeKind.t =
       Obj.magic (s lsr 4)

     let make is_left is_right has_left has_right kind =
       ((Obj.magic kind) lsl 4) lor
         ((int_of_bool is_left) lsl 3) lor
         ((int_of_bool is_right) lsl 2) lor
         ((int_of_bool has_left) lsl 1) lor
         (int_of_bool has_right)

   end

   type node_status = {
     sat : StateSet.t;  (* States that are satisfied at the current node *)
     todo : StateSet.t; (* States that remain to be proven *)
                        (* For every node_status and automaton a:
                           a.states - (sat U todo) = unsat *)
     summary : NodeSummary.t; (* Summary of the shape of the node *)
   }
(* Describe what is kept at each node for a run *)

   module NodeStatus =
     struct
       include Hcons.Make(struct
         type t = node_status
         let equal c d =
           c == d ||
             c.sat == d.sat &&
             c.todo == d.todo &&
             c.summary == d.summary

         let hash c =
           HASHINT3((c.sat.StateSet.id :> int),
                    (c.todo.StateSet.id :> int),
                    c.summary)
       end
       )
       let print ppf s =
         fprintf ppf
           "{ sat: %a; todo: %a; summary: _ }"
           StateSet.print s.node.sat
           StateSet.print s.node.todo
     end

   let dummy_status =
     NodeStatus.make { sat = StateSet.empty;
                       todo = StateSet.empty;
                       summary = NodeSummary.dummy;
                     }


   type run = {
     tree : T.t ;
     (* The argument of the run *)
     auto : Ata.t;
     (* The automaton to be run *)
     status : NodeStatus.t array;
     (* A mapping from node preorders to NodeStatus *)
     unstable : Bitvector.t;
     (* A bitvector remembering whether a subtree is stable *)
     mutable redo : bool;
     (* A boolean indicating whether the run is incomplete *)
     mutable pass : int;
     (* The number of times this run was updated *)
     mutable cache2 : Ata.Formula.t Cache.N2.t;
     (* A cache from states * label to list of transitions *)
     mutable cache5 : NodeStatus.t Cache.N5.t;
   }

   let pass r = r.pass
   let stable r = not r.redo
   let auto r = r.auto
   let tree r = r.tree


   let dummy_form = Ata.Formula.stay State.dummy

   let make auto tree =
     let len = T.size tree in
     {
       tree = tree;
       auto = auto;
       status = Array.create len dummy_status;
       unstable = Bitvector.create ~init:true len;
       redo = true;
       pass = 0;
       cache2 = Cache.N2.create dummy_form;
       cache5 = Cache.N5.create dummy_status;
     }

   let get_status a i =
     if i < 0 then dummy_status else Array.get a i

   let unsafe_get_status a i =
     if i < 0 then dummy_status else Array.unsafe_get a i

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

   let html tree node i config msg =
     let config = config.NodeStatus.node in
     Html.trace (T.preorder tree node) i
       "node: %i<br/>%s<br/>sat: %a<br/>todo: %a<br/>round: %i<br/>"
       (T.preorder tree node)
       msg
       StateSet.print config.sat
       StateSet.print config.todo
       i


   let debug msg tree node i config =
     let config = config.NodeStatus.node in
     eprintf
       "DEBUG:%s node: %i\nsat: %a\ntodo: %a\nround: %i\n"
       msg
       (T.preorder tree node)
       StateSet.print config.sat
       StateSet.print config.todo
       i

   let get_form cache2 auto tag q =
     let phi =
       Cache.N2.find cache2 (tag.QName.id :> int) (q :> int)
     in
     if phi == dummy_form then
       let phi = Ata.get_form auto tag q in
       let () =
         Cache.N2.add
           cache2
           (tag.QName.id :> int)
           (q :> int) phi
       in phi
     else phi

   type trivalent = False | True | Unknown
   let of_bool = function false -> False | true -> True
   let or_ t1 t2 =
     match t1 with
       False -> t2
     | True -> True
     | Unknown -> if t2 == True then True else Unknown

   let and_ t1 t2 =
     match t1 with
       False -> False
     | True -> t2
     | Unknown -> if t2 == False then False else Unknown

 (* Define as macros to get lazyness *)
DEFINE OR_(t1,t2) =
     let __t1 = (t1) in
     match t1 with
       False -> (t2)
     | True -> True
     | Unknown -> if (t2) == True then True else Unknown

DEFINE AND_(t1,t2) =
     let __t1 = (t1) in
     match t1 with
       False -> False
     | True -> (t2)
     | Unknown -> if (t2) == False then False else Unknown


   let eval_form phi fcs nss ps ss summary =
     let open Ata in
         let rec loop phi =
           begin match Formula.expr phi with
           | Boolean.False -> False
           | Boolean.True -> True
           | Boolean.Atom (a, b) ->
               begin
                 let open NodeSummary in
                     match a.Atom.node with
                     | Move (m, q) ->
                         let { NodeStatus.node = n_sum; _ } as sum =
                           match m with
                             `First_child -> fcs
                           | `Next_sibling -> nss
                           | `Parent | `Previous_sibling -> ps
                           | `Stay -> ss
                         in
                         if sum == dummy_status || StateSet.mem q n_sum.todo then
                           Unknown
                         else
                           of_bool (b == StateSet.mem q n_sum.sat)
                     | Is_first_child -> of_bool (b == is_left summary)
                     | Is_next_sibling -> of_bool (b == is_right summary)
                     | Is k -> of_bool (b == (k == kind summary))
                     | Has_first_child -> of_bool (b == has_left summary)
                     | Has_next_sibling -> of_bool (b == has_right summary)
               end
           | Boolean.And(phi1, phi2) -> AND_ (loop phi1, loop phi2)
           | Boolean.Or (phi1, phi2) -> OR_ (loop phi1, loop phi2)
           end
         in
         loop phi


   let eval_trans_aux auto cache2 tag fcs nss ps old_status =
     let { sat = old_sat;
           todo = old_todo;
           summary = old_summary } as os_node = old_status.NodeStatus.node
     in
     let sat, todo =
       StateSet.fold (fun q ((a_sat, a_todo) as acc) ->
         let phi =
           get_form cache2 auto tag q
         in
         let v = eval_form phi fcs nss ps old_status old_summary in
         match v with
           True -> StateSet.add q a_sat, a_todo
         | False -> acc
         | Unknown -> a_sat, StateSet.add q a_todo
       ) old_todo (old_sat, StateSet.empty)
     in
     if old_sat != sat || old_todo != todo then
       NodeStatus.make { os_node with sat; todo }
     else old_status


   let eval_trans auto cache2 cache5 tag fcs nss ps ss =
     let rec loop old_status =
       let new_status =
         eval_trans_aux auto cache2 tag fcs nss ps old_status
       in
       if new_status == old_status then old_status else loop new_status
     in
     let fcsid = (fcs.NodeStatus.id :> int) in
     let nssid = (nss.NodeStatus.id :> int) in
     let psid = (ps.NodeStatus.id :> int) in
     let ssid = (ss.NodeStatus.id :> int) in
     let tagid = (tag.QName.id :> int) in
     let res = Cache.N5.find cache5 tagid ssid fcsid nssid psid in
     if res != dummy_status then res
     else let new_status = loop ss in
          Cache.N5.add cache5 tagid ssid fcsid nssid psid new_status;
          new_status



  let top_down run =
    let tree = run.tree in
    let auto = run.auto in
    let status = run.status in
    let cache2 = run.cache2 in
    let cache5 = run.cache5 in
    let unstable = run.unstable in
    let init_todo = StateSet.diff (Ata.get_states auto) (Ata.get_starting_states auto) 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
        (* We enter the node from its parent *)

        let status0 =
          let c = unsafe_get_status status node_id in
          if c == dummy_status then
            (* first time we visit the node *)
            NodeStatus.make
              { sat = StateSet.empty;
                todo = init_todo;
                summary = NodeSummary.make
                  (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");

        (* get the node_statuses for the first child, next sibling and parent *)
        let ps = unsafe_get_status status (T.preorder tree parent) in
        let fcs = unsafe_get_status status fc_id in
        let nss = unsafe_get_status status ns_id in
        (* evaluate the transitions with all this statuses *)
        let status1 = eval_trans auto cache2 cache5 tag fcs nss ps status0 in
        TRACE(html tree node _i config1 "Updating transitions");

        (* update the cache if the status of the node changed *)

        if status1 != status0 then status.(node_id) <- status1;
        (* recursively traverse the first child *)
        let unstable_left = loop fc in
        (* here we re-enter the node from its first child,
           get the new status of the first child *)
        let fcs1 = unsafe_get_status status fc_id in
        (* update the status *)
        let status2 = eval_trans auto cache2 cache5 tag fcs1 nss ps status1 in

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

        if status2 != status1 then status.(node_id) <- status2;
        let unstable_right = loop ns in
        let nss1 = unsafe_get_status status ns_id in
        let status3 = eval_trans auto cache2 cache5 tag fcs1 nss1 ps status2 in

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

        if status3 != status2 then status.(node_id) <- status3;

        let unstable_self =
          (* if either our left or right child is unstable or if we still have transitions
             pending, the current node is unstable *)
          unstable_left
          || unstable_right
          || StateSet.empty != status3.NodeStatus.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
    run.redo <- loop (T.root tree);
    run.pass <- run.pass + 1

(*
  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
*)

  let get_results run =
    let cache = run.status in
    let auto = run.auto in
    let tree = run.tree in
    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).NodeStatus.node.sat
            (get_selecting_states auto)) then node::acc1
        else acc1
    in
    loop (T.root tree) []


  let get_full_results run =
    let cache = run.status in
    let auto = run.auto in
    let tree = run.tree in
    let res_mapper = Hashtbl.create MED_H_SIZE in
    let () =
      StateSet.iter
        (fun q -> Hashtbl.add res_mapper q [])
        (Ata.get_selecting_states auto)
    in
    let dummy = [ T.nil ] in
    let res_mapper = Cache.N1.create dummy in
    let () =
      StateSet.iter
        (fun q -> Cache.N1.add res_mapper (q :> int) [])
        (Ata.get_selecting_states auto)
    in
    let rec loop node =
      if node != T.nil then
        let () = loop (T.next_sibling tree node) in
        let () = loop (T.first_child tree node) in
        StateSet.iter
          (fun q ->
            let res = Cache.N1.find res_mapper (q :> int) in
            if res != dummy then
              Cache.N1.add res_mapper (q :> int) (node::res)
          )
          cache.(T.preorder tree node).NodeStatus.node.sat
    in
    loop (T.root tree);
    List.rev (StateSet.fold
                (fun q acc -> (q, Cache.N1.find res_mapper (q :> int))::acc)
                (Ata.get_selecting_states auto) [])

  let prepare_run run list =
    let tree = run.tree in
    let auto = run.auto in
    let status = run.status in
    List.iter (fun node ->
      let parent = T.parent tree node in
      let fc = T.first_child tree node in
      let ns = T.next_sibling tree node in
      let status0 =
        NodeStatus.make
          { sat = Ata.get_starting_states auto;
            todo =
              StateSet.diff (Ata.get_states auto) (Ata.get_starting_states auto);
            summary = NodeSummary.make
              (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 *)
          }
      in
      let node_id = T.preorder tree node in
      status.(node_id) <- status0) list


  let eval full auto tree nodes =
    let run = make auto tree in
    prepare_run run nodes;
    while run.redo do
      top_down run
    done;
    if full then `Full (get_full_results run)
    else `Normal (get_results run)

  let full_eval auto tree nodes =
    match eval true auto tree nodes with
      `Full l -> l
    | _ -> assert false

  let eval auto tree nodes =
    match eval false auto tree nodes with
      `Normal l -> l
    | _ -> assert false

end