(*
    ||M||  This file is part of HELM, an Hypertextual, Electronic        
    ||A||  Library of Mathematics, developed at the Computer Science     
    ||T||  Department, University of Bologna, Italy.                     
    ||I||                                                                
    ||T||  HELM is free software; you can redistribute it and/or         
    ||A||  modify it under the terms of the GNU General Public License   
    \   /  version 2 or (at your option) any later version.      
     \ /   This software is distributed as is, NO WARRANTY.     
      V_______________________________________________________________ *)

(* $Id$ *)

exception DisambiguationError of
 int *
 ((Stdpp.location list * string * string) list *
  (DisambiguateTypes.domain_item * string) list *
  (Stdpp.location * string) Lazy.t * bool) list list

open Printf

let debug = false;;
let debug_print s =
 if debug then prerr_endline (Lazy.force s);;

module Callbacks =
  struct
    let interactive_user_uri_choice ~selection_mode ?ok
          ?(enable_button_for_non_vars = true) ~title ~msg ~id uris =
              assert false

    let interactive_interpretation_choice interp =
            assert false

    let input_or_locate_uri ~(title:string) ?id () = 
            assert false
  end
  
module Disambiguator = NDisambiguate.Make (Callbacks)

let only_one_pass = ref false;;

let disambiguate_thing ~aliases ~universe
  ~(f:?fresh_instances:bool ->
      aliases:NCic.term DisambiguateTypes.environment ->
      universe:NCic.term DisambiguateTypes.multiple_environment option ->
      'a -> 'b)
  ~(drop_aliases: ?minimize_instances:bool -> 'b -> 'b)
  ~(drop_aliases_and_clear_diff: 'b -> 'b)
  (thing: 'a)
=
  assert (universe <> None);
  let library = false, DisambiguateTypes.Environment.empty, None in
  let multi_aliases = false, DisambiguateTypes.Environment.empty, universe in
  let mono_aliases = true, aliases, Some DisambiguateTypes.Environment.empty in
  let passes = (* <fresh_instances?, aliases, coercions?> *)
   if !only_one_pass then
    [ (true, mono_aliases, false) ]
   else
    [ (true, mono_aliases, false);
      (true, multi_aliases, false);
      (true, mono_aliases, true);
      (true, multi_aliases, true);
      (true, library, false); 
        (* for demo to reduce the number of interpretations *)
      (true, library, true);
    ]
  in
  let try_pass (fresh_instances, (_, aliases, universe), insert_coercions) =
    CicRefine.insert_coercions := insert_coercions;
    f ~fresh_instances ~aliases ~universe thing
  in
  let set_aliases (instances,(use_mono_aliases,_,_),_) (_, user_asked as res) =
   if use_mono_aliases then
    drop_aliases ~minimize_instances:true res (* one shot aliases *)
   else if user_asked then
    drop_aliases ~minimize_instances:true res (* one shot aliases *)
   else
    drop_aliases_and_clear_diff res
  in
  let rec aux i errors passes =
  debug_print (lazy ("Pass: " ^ string_of_int i));
   match passes with
      [ pass ] ->
        (try
          set_aliases pass (try_pass pass)
         with Disambiguate.NoWellTypedInterpretation (offset,newerrors) ->
          raise (DisambiguationError (offset, errors @ [newerrors])))
    | hd :: tl ->
        (try
          set_aliases hd (try_pass hd)
        with Disambiguate.NoWellTypedInterpretation (_offset,newerrors) ->
         aux (i+1) (errors @ [newerrors]) tl)
    | [] -> assert false
  in
  let saved_insert_coercions = !CicRefine.insert_coercions in
  try
    let res = aux 1 [] passes in
    CicRefine.insert_coercions := saved_insert_coercions;
    res
  with exn ->
    CicRefine.insert_coercions := saved_insert_coercions;
    raise exn

type disambiguator_thing =
 { do_it :
    'a 'b.
    aliases:NCic.term DisambiguateTypes.environment ->
    universe:NCic.term DisambiguateTypes.multiple_environment option ->
    f:(?fresh_instances:bool ->
       aliases:NCic.term DisambiguateTypes.environment ->
       universe:NCic.term DisambiguateTypes.multiple_environment option ->
       'a -> 'b * bool) ->
    drop_aliases:(?minimize_instances:bool -> 'b * bool -> 'b * bool) ->
    drop_aliases_and_clear_diff:('b * bool -> 'b * bool) -> 'a -> 'b * bool
 }

let disambiguate_thing =
 let profiler = HExtlib.profile "disambiguate_thing" in
  { do_it =
     fun ~aliases ~universe ~f ~drop_aliases ~drop_aliases_and_clear_diff thing
     -> profiler.HExtlib.profile
         (disambiguate_thing ~aliases ~universe ~f ~drop_aliases
           ~drop_aliases_and_clear_diff) thing
  }

let drop_aliases ?(minimize_instances=false) (choices, user_asked) =
 let module D = DisambiguateTypes in
 let minimize d =
  if not minimize_instances then
   d
  else
   let rec aux =
    function
       [] -> []
     | (D.Symbol (s,n),((descr,_) as ci)) as he::tl when n > 0 ->
         if
          List.for_all
           (function
               (D.Symbol (s2,_),(descr2,_)) -> s2 <> s || descr = descr2
             | _ -> true
           ) d
         then
          (D.Symbol (s,0),ci)::(aux tl)
         else
          he::(aux tl)
     | (D.Num n,((descr,_) as ci)) as he::tl when n > 0 ->
         if
          List.for_all
           (function (D.Num _,(descr2,_)) -> descr = descr2 | _ -> true) d
         then
          (D.Num 0,ci)::(aux tl)
         else
          he::(aux tl)
      | he::tl -> he::(aux tl)
   in
    aux d
 in
  (List.map (fun (d, a, b, c) -> minimize d, a, b, c) choices),
  user_asked

let drop_aliases_and_clear_diff (choices, user_asked) =
  (List.map (fun (_, a, b, c) -> [], a, b, c) choices),
  user_asked

let disambiguate_term ~context ~metasenv ~subst ?goal
  ~aliases ~universe term
 =
  let f =
    Disambiguator.disambiguate_term ~context ~metasenv ~subst ?goal
     ~lookup_in_library:(fun _ _ -> assert false)
  in
  disambiguate_thing.do_it ~aliases ~universe ~f ~drop_aliases
   ~drop_aliases_and_clear_diff term

let disambiguate_obj ~aliases ~universe ~uri obj =
        assert false (*
  assert (fresh_instances = None);
  let f = Disambiguator.disambiguate_obj ~uri ~lookup_in_library:(fun _ _ -> assert false) in
  disambiguate_thing.do_it ~aliases ~universe ~f ~drop_aliases
   ~drop_aliases_and_clear_diff obj
   *)