(***********************************************************************)
(*                                                                     *)
(*                               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 2013-03-10 23:31:33 CET by Kim Nguyen>
*)

INCLUDE "utils.ml"
open Format
open Utils

module Make (T : Tree.Sig.S) = struct

  type cache = (int, StateSet.t) Hashtbl.t

  let get c t n =
    try Hashtbl.find c (T.preorder t n)
    with Not_found -> StateSet.empty

  let set c t n v = Hashtbl.replace c (T.preorder t n) v
  let eval_form  phi tree node fcs nss ps ss =
    let rec loop phi =
      match Ata.SFormula.expr phi with
        Formula.True -> true
      | Formula.False -> false
      | Formula.Atom a ->
          let p, b, q = Ata.Atom.node a in
          let pos =
            let open Ata in
            match p with
            | First_child -> StateSet.mem q fcs
            | Next_sibling ->  StateSet.mem q nss
            | Parent | Previous_sibling -> StateSet.mem q ps
            | Stay -> StateSet.mem q ss
            | Is_first_child ->
                node == (T.first_child tree (T.parent tree node))
            | Is_next_sibling ->
                node == (T.next_sibling tree (T.parent tree node))
            | Is k -> k == (T.kind tree node)
            | Has_first_child ->
                T.nil != T.first_child tree node
            | Has_next_sibling ->
                T.nil != T.next_sibling tree node
          in
          if Ata.is_move p && (not b) then
            eprintf "Warning: Invalid negative atom %a" Ata.Atom.print a;
          b == pos
      | Formula.And(phi1, phi2) -> loop phi1 && loop phi2
      | Formula.Or (phi1, phi2) -> loop phi1 || loop phi2
    in
    loop phi

  let eval_trans l tree node fcs nss ps ss acc =
    List.fold_left (fun (acct, accs) ((q, phi) as trs) ->
      if StateSet.mem q accs then (acct, accs) else
      if eval_form phi tree node fcs nss ps ss then
        (acct, StateSet.add q accs)
      else
        (trs::acct, accs)
    ) ([], acc) l

  let top_down_run auto tree node cache i =
    let redo = ref false in
    let rec loop node =
      if node != T.nil then 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 states0 = get cache tree node in
        let tag = T.tag tree node in
        let trans0 = Ata.get_trans auto auto.Ata.states tag in
        let ps = get cache tree parent in
        let fcs = get cache tree fc in
        let nss = get cache tree ns in
        eprintf "-- [Iteration % 4d] --\n node: %a\n%!" i T.print_node node;
        List.iter (fun (q, phi) -> eprintf " %a -> %a\n"
          State.print q Ata.SFormula.print phi) trans0;
        eprintf "----------------------\n%!";
        let trans1, states1 =
          eval_trans trans0 tree node fcs nss ps states0 states0
        in
        if states1 != states0 then set cache tree node states1;
        let () = loop fc in
        let fcs1 = get cache tree fc in
        let trans2, states2 =
          eval_trans trans1 tree node fcs1 nss ps states1 states1
        in
        if states2 != states1 then set cache tree node states2;
        let () = loop ns in
        let _, states3 =
          eval_trans trans2 tree node fcs1 (get cache tree ns) ps states2 states2
        in
        if states3 != states2 then set cache tree node states3;
        if states0 != states3 && (not !redo) then redo := true
      end
    in
    loop node;
    !redo

  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) auto.Ata.selection_states then
          node::acc1
        else
          acc1
    in
    loop node []

  let eval auto tree node =
    let cache = Hashtbl.create 511 in
    let redo = ref true in
    let iter = ref 0 in
    while !redo do
      redo := top_down_run auto tree node cache !iter;
      incr iter;
    done;
    get_results auto tree node cache

end