(***********************************************************************)
(*                                                                     *)
(*                               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"
INCLUDE "debug.ml"

open Format
open Misc
open Bigarray

type stats = { mutable pass : int;
               tree_size : int;
               mutable fetch_trans_cache_access : int;
               mutable fetch_trans_cache_hit : int;
               mutable eval_trans_cache_access : int;
               mutable eval_trans_cache_hit : int;
               mutable nodes_per_run : int list;
             }

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
     (*
       ...44443210
       ...4444 -> kind
       3 -> has_right
       2 -> has_left
       1 -> is_right
       0 -> is_left
     *)
  let is_left (s : t) : bool =
    s land 1 != 0

  let is_right (s : t) : bool =
    s land 0b10 != 0

  let has_left (s : t) : bool =
    s land 0b100 != 0

  let has_right (s : t) : bool =
       s land 0b1000 != 0

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

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

   let dummy_set = StateSet.singleton State.dummy



IFDEF HTMLTRACE
THEN
   type sat_array = StateSet.t array list
   DEFINE IFHTML(a,b) = (a)
ELSE
   type sat_array = StateSet.t array
   DEFINE IFHTML(a,b) = (b)
END

   let unsafe_get a i =
     if i < 0 then StateSet.empty else
       Array.unsafe_get (IFHTML(List.hd a, a)) i

   let unsafe_set a i v old_v =
     if v != old_v then
       Array.unsafe_set (IFHTML(List.hd a, a)) i v

   type 'a run = {
     tree : 'a ;
     (* The argument of the run *)
     auto : Ata.t;
     (* The automaton to be run *)
     mutable sat: sat_array;
     (* A mapping from node preorders to states satisfied at that node *)
     mutable pass : int;
     (* Number of run we have performed *)
     mutable fetch_trans_cache : Ata.Formula.t Cache.N2.t;
     (* A cache from states * label to list of transitions *)
     mutable td_cache : StateSet.t Cache.N6.t;
     mutable bu_cache : StateSet.t Cache.N6.t;
     (* Two 6-way caches used during the top-down and bottom-up phase
        label * self-set * fc-set * ns-set * parent-set * node-shape -> self-set
     *)
     node_summaries: (int, int16_unsigned_elt, c_layout) Array1.t;
     stats : stats;
   }

   let dummy_form = Ata.Formula.stay State.dummy

   let get_form run tag q =
     let auto = run.auto in
     let fetch_trans_cache = run.fetch_trans_cache in
     let stats = run.stats in
     let phi =
       stats.fetch_trans_cache_access <- stats.fetch_trans_cache_access + 1;
       Cache.N2.find fetch_trans_cache (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
           fetch_trans_cache
           (tag.QName.id :> int)
           (q :> int) phi
       in phi
     else begin
       stats.fetch_trans_cache_hit <- stats.fetch_trans_cache_hit + 1;
       phi
     end


   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) ->
                       b && StateSet.mem q (
                           match m with
                             `First_child -> fcs
                           | `Next_sibling -> nss
                           | `Parent | `Previous_sibling -> ps
                           | `Stay -> ss
                       )
                     | Is_first_child -> b == is_left summary
                     | Is_next_sibling -> b == is_right summary
                     | Is k -> b == (k == kind summary)
                     | Has_first_child -> b == has_left summary
                     | Has_next_sibling -> b == has_right summary
               end
           | Boolean.And(phi1, phi2) -> loop phi1 && loop phi2
           | Boolean.Or (phi1, phi2) -> loop phi1 || loop phi2
           end
         in
         loop phi


   let eval_trans_aux run tag summary fcs nss ps sat todo  =
     StateSet.fold (fun q (a_sat) ->
       let phi =
         get_form run tag q
       in
       if eval_form phi fcs nss ps a_sat summary then
         StateSet.add q a_sat
       else a_sat
     ) todo sat


   let rec eval_trans_fix run tag summary fcs nss ps sat todo  =
     let new_sat =
       eval_trans_aux run tag summary fcs nss ps sat todo
     in
     if new_sat == sat then sat else
       eval_trans_fix run tag summary fcs nss ps new_sat todo


   let eval_trans run trans_cache tag summary fcs nss ps ss todo =
     let stats = run.stats in
     let fcsid = (fcs.StateSet.id :> int) in
     let nssid = (nss.StateSet.id :> int) in
     let psid = (ps.StateSet.id :> int) in
     let ssid = (ss.StateSet.id :> int) in
     let tagid = (tag.QName.id :> int) in

     let res = Cache.N6.find trans_cache tagid summary ssid fcsid nssid psid in
     stats.eval_trans_cache_access <- 1 + stats.eval_trans_cache_access;
     if res != dummy_set then begin
       stats.eval_trans_cache_hit <- 1 + stats.eval_trans_cache_hit;
       res
     end else let new_sat =
                eval_trans_fix run tag summary fcs nss ps ss todo
              in
              Cache.N6.add trans_cache tagid summary ssid fcsid nssid psid new_sat;
              new_sat


module Make (T : Tree.S) (L : Node_list.S with type node = T.node) =
 struct

   let make auto tree =
     let len = T.size tree in
     let ba = Array1.create int16_unsigned c_layout len in
     Array1.fill ba 0;
     {
       tree = tree;
       auto = auto;
       sat = (let a = Array.create len StateSet.empty in
             IFHTML([a], a));
       pass = 0;
       fetch_trans_cache = Cache.N2.create dummy_form;
       td_cache = Cache.N6.create dummy_set;
       bu_cache = Cache.N6.create dummy_set;
       node_summaries = ba;
       stats = {
         pass = 0;
         tree_size = len;
         fetch_trans_cache_access = 0;
         fetch_trans_cache_hit = 0;
         eval_trans_cache_access = 0;
         eval_trans_cache_hit = 0;
         nodes_per_run = [];
       }
     }


   let top_down run update_res =
     let num_visited = ref 0 in
     let i = run.pass in
     let tree = run.tree in
     let auto = run.auto in
     let states_by_rank = Ata.get_states_by_rank auto in
     let td_todo = states_by_rank.(i) in
     let bu_todo =
       if i == Array.length states_by_rank - 1 then StateSet.empty
       else
         states_by_rank.(i+1)
     in
     let last_run = i >= Array.length states_by_rank - 2 in
     let rec loop_td_and_bu node parent parent_sat =
       if node == T.nil then StateSet.empty
       else begin
         incr num_visited;
         let tag = T.tag tree node in
         let node_id = T.preorder tree node in
         let fc = T.first_child tree node in
         let ns = T.next_sibling tree node in
         (* We enter the node from its parent *)
         let summary =
           let s = Array1.unsafe_get run.node_summaries node_id in
           if  s != 0 then s else
             let s =
              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
             run.node_summaries.{node_id} <- s; s
         in
        let status0 = unsafe_get run.sat node_id in
        (* get the node_statuses for the first child, next sibling and parent *)
        (* evaluate the transitions with all this statuses *)
        let status1 =
          eval_trans run
            run.td_cache tag
            summary
            (unsafe_get run.sat (T.preorder tree fc))
            (unsafe_get run.sat (T.preorder tree ns))
            parent_sat
            status0 td_todo
        in
        if status1 == StateSet.empty && status0 != StateSet.empty
        then StateSet.empty else
          (* update the cache if the status of the node changed
             unsafe_set run.sat node_id status1 status0;*)
          if bu_todo == StateSet.empty then begin
            unsafe_set run.sat node_id status1 status0; (* write the td_states *)
            update_res false status1 node;
            let _ = loop_td_and_bu fc node status1 in
            loop_td_and_bu ns node status1 (* tail call *)
          end else
            let fcs1, nss1 =
              if last_run then
                let nss1 = loop_td_and_bu ns node status1 in
                let fcs1 = loop_td_and_bu fc node status1 in
                fcs1, nss1
              else
                let fcs1 = loop_td_and_bu fc node status1 in
                let nss1 = loop_td_and_bu ns node status1 in
                fcs1, nss1
            in
            let status2 =
              eval_trans run run.bu_cache tag
                summary fcs1
                nss1
                parent_sat
                status1 bu_todo
            in
            unsafe_set run.sat node_id status2 status0;
            if last_run && status2 != StateSet.empty then update_res true status2 node;
            status2
        end
    in
    let _ = loop_td_and_bu (T.root tree) T.nil dummy_set in
    run.pass <- run.pass + 2;
    run.stats.pass <- run.stats.pass + 1;
    run.stats.nodes_per_run <- !num_visited :: run.stats.nodes_per_run



   let mk_update_result auto =
     let sel_states = Ata.get_selecting_states auto in
     let res = L.create () in
     (fun prepend sat node ->
       if StateSet.intersect sel_states sat then begin
         if prepend then L.push_front node res else
           L.push_back node res
       end),
     (fun () -> res)


   let mk_update_full_result auto =
     let dummy = L.create () in
     let res_mapper = Cache.N1.create dummy in
     let () =
       StateSet.iter
         (fun q -> Cache.N1.add res_mapper (q :> int) (L.create()))
         (Ata.get_selecting_states auto)
     in
     (fun prepend sat node ->
       StateSet.iter
         (fun q ->
           let res = Cache.N1.find res_mapper (q :> int) in
           if res != dummy then begin
             if prepend then L.push_front node res
             else L.push_back node res
           end
         ) sat),
     (fun () ->
       StateSet.fold_right
         (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 sat = IFHTML((List.hd run.sat), run.sat) in
    let sat0 = Ata.get_starting_states auto in
    L.iter (fun node ->
      let node_id = T.preorder tree node in
      sat.(node_id) <- sat0) list


  let compute_run auto tree nodes update_res =
    let run = make auto tree in
    prepare_run run nodes;
    let rank = Ata.get_max_rank auto in
    while run.pass <= rank do
      top_down run update_res;
      IFHTML((run.sat <- (Array.copy (List.hd run.sat)) :: run.sat), ());
      run.td_cache <- Cache.N6.create dummy_set;
      run.bu_cache <- Cache.N6.create dummy_set;
    done;
    IFHTML((run.sat <- List.tl run.sat), ());
    IFHTML(Html_trace.gen_trace auto run.sat (module T : Tree.S with type t = T.t) tree ,());
    run


  let last_stats = ref None

  let full_eval auto tree nodes =
    let update_full,get_full = mk_update_full_result auto in
    let run = compute_run auto tree nodes update_full in
    last_stats := Some run.stats;
    get_full ()

  let eval auto tree nodes =
    let update_res,get_res = mk_update_result auto in
    let run = compute_run auto tree nodes update_res in
    last_stats := Some run.stats;
    get_res ()

  let stats () = match !last_stats with
      Some s -> s.nodes_per_run <- List.rev s.nodes_per_run;s
    | None -> failwith "Missing stats"

end