(* Copyright (C) 2004, HELM Team.
 * 
 * This file is part of HELM, an Hypertextual, Electronic
 * Library of Mathematics, developed at the Computer Science
 * Department, University of Bologna, Italy.
 * 
 * HELM is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * HELM is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HELM; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA  02111-1307, USA.
 * 
 * For details, see the HELM World-Wide-Web page,
 * http://helm.cs.unibo.it/
 *)

open Printf

module Constr = MetadataConstraints
module PET = ProofEngineTypes 

let nonvar s =
  let len = String.length s in
  let suffix = String.sub s (len-4) 4 in
  not (suffix  = ".var")

let locate ~(dbd:Mysql.dbd) ?(vars = false) name =
  let query =
    sprintf "SELECT source FROM %s WHERE value = \"%s\""
      MetadataTypes.name_tbl name
  in
  let result = Mysql.exec dbd query in
  List.filter nonvar
    (Mysql.map result
      (fun cols -> match cols.(0) with Some s -> s | _ -> assert false))

let match_term ~(dbd:Mysql.dbd) ty =
  let metadata = MetadataExtractor.compute ~body:None ~ty in
  let constants_no =
    MetadataConstraints.StringSet.cardinal (MetadataConstraints.constants_of ty)
  in
  let constraints = List.map MetadataTypes.constr_of_metadata metadata in
  Constr.at_least ~dbd ~full_card:(MetadataConstraints.Eq constants_no)
    constraints

let ( ** ) x y = int_of_float ((float_of_int x) ** (float_of_int y))

let signature_of_hypothesis context =
  List.fold_left
    (fun set hyp ->
      match hyp with
      | None -> set
      | Some (_, Cic.Decl t)
      | Some (_, Cic.Def (t, _)) ->
          Constr.StringSet.union set (Constr.constants_of t))
    Constr.StringSet.empty context

let intersect uris siguris =
  let set1 = List.fold_right Constr.StringSet.add uris Constr.StringSet.empty in
  let set2 =
    List.fold_right Constr.StringSet.add siguris Constr.StringSet.empty
  in
  let inter = Constr.StringSet.inter set1 set2 in
  List.filter (fun s -> Constr.StringSet.mem s inter) uris

let filter_uris_forward ~dbd (main, constants) uris =
  let main_uris =
    match main with
    | None -> []
    | Some (main, types) -> main :: types
  in
  let full_signature =
    List.fold_right Constr.StringSet.add main_uris constants
  in
  List.filter (Constr.at_most ~dbd ~where:`Statement full_signature) uris

let filter_uris_backward ~dbd ~facts signature uris =
  let siguris =
    List.map snd 
      (MetadataConstraints.sigmatch ~dbd ~facts ~where:`Statement signature)
  in
    intersect uris siguris 

let compare_goal_list proof goal1 goal2 =
  let _,metasenv,_,_ = proof in
  let (_, ey1, ty1) = CicUtil.lookup_meta goal1 metasenv in
  let (_, ey2, ty2) =  CicUtil.lookup_meta goal2 metasenv in
  let ty_sort1 = CicTypeChecker.type_of_aux' metasenv ey1 ty1 in
  let ty_sort2 = CicTypeChecker.type_of_aux' metasenv ey2 ty2 in
  let prop1 =
    if CicReduction.are_convertible ey1 (Cic.Sort Cic.Prop) ty_sort1 then 0
    else 1
  in
  let prop2 =
    if CicReduction.are_convertible ey2 (Cic.Sort Cic.Prop) ty_sort2 then 0
    else 1
  in
  prop1 - prop2

let hint ~(dbd:Mysql.dbd) ?(facts=false) ?signature ((proof, goal) as status) =
  let (_, metasenv, _, _) = proof in
  let (_, context, ty) = CicUtil.lookup_meta goal metasenv in
  let (uris, (main, sig_constants)) =
    match signature with
    | Some signature -> (Constr.sigmatch ~dbd ~facts signature, signature)
    | None -> (Constr.cmatch' ~dbd ~facts ty, Constr.signature_of ty)
  in
  let uris = List.filter nonvar (List.map snd uris) in
  let uris = List.filter Hashtbl_equiv.not_a_duplicate uris in
  let types_constants =
    match main with
    | None -> Constr.StringSet.empty
    | Some (main, types) ->
        List.fold_right Constr.StringSet.add (main :: types)
          Constr.StringSet.empty
  in
  let hyp_constants =
    Constr.StringSet.diff (signature_of_hypothesis context) types_constants
  in
Constr.StringSet.iter prerr_endline hyp_constants;
  let other_constants = Constr.StringSet.union sig_constants hyp_constants in
  let uris = 
    let pow = 2 ** (Constr.StringSet.cardinal other_constants) in
    if ((List.length uris < pow) or (pow <= 0))
    then begin
      prerr_endline "MetadataQuery: large sig, falling back to old method";
      filter_uris_forward ~dbd (main, other_constants) uris
    end else
      filter_uris_backward ~dbd ~facts (main, other_constants) uris
  in
  let rec aux = function
    | [] -> []
    | uri :: tl ->
        (let status' =
            try
              let (proof, goal_list) =
(*                prerr_endline ("STO APPLICANDO " ^ uri); *)
		PET.apply_tactic
                  (PrimitiveTactics.apply_tac
		    ~term:(CicUtil.term_of_uri uri))
                  status
              in
              let goal_list =
                List.stable_sort (compare_goal_list proof) goal_list
              in
              Some (uri, (proof, goal_list))
            with ProofEngineTypes.Fail _ -> None
          in
          match status' with
          | None -> aux tl
          | Some status' ->
              status' :: aux tl)
  in
  List.stable_sort
    (fun (_, (_, goals1)) (_, (_, goals2)) ->
      Pervasives.compare (List.length goals1) (List.length goals2))
    (aux uris)

(* experimental_hint is a version of hint for experimental 
    purposes. It uses auto_tac_verbose instead of auto tac.
    Auto_tac verbose also returns a substitution - for the moment 
    as a function from cic to cic, to be changed into an association
    list in the future -. This substitution is used to build a
    hash table of the inspected goals with their associated proofs.
    The cose is a cut and paste of the previous one: at the end 
    of the experimentation we shall make a choice. *)

let experimental_hint 
  ~(dbd:Mysql.dbd) ?(facts=false) ?signature ((proof, goal) as status) =
  let (_, metasenv, _, _) = proof in
  let (_, context, ty) = CicUtil.lookup_meta goal metasenv in
  let (uris, (main, sig_constants)) =
    match signature with
    | Some signature -> 
	(Constr.sigmatch ~dbd ~facts signature, signature)
    | None -> 
	(Constr.cmatch' ~dbd ~facts ty, Constr.signature_of ty)
  in
  let uris = List.filter nonvar (List.map snd uris) in
  let uris = List.filter Hashtbl_equiv.not_a_duplicate uris in
  let types_constants =
    match main with
    | None -> Constr.StringSet.empty
    | Some (main, types) ->
        List.fold_right Constr.StringSet.add (main :: types)
          Constr.StringSet.empty
  in
  let hyp_constants =
    Constr.StringSet.diff (signature_of_hypothesis context) types_constants
  in
Constr.StringSet.iter prerr_endline hyp_constants;
  let other_constants = Constr.StringSet.union sig_constants hyp_constants in
  let uris = 
    let pow = 2 ** (Constr.StringSet.cardinal other_constants) in
    if ((List.length uris < pow) or (pow <= 0))
    then begin
      prerr_endline "MetadataQuery: large sig, falling back to old method";
      filter_uris_forward ~dbd (main, other_constants) uris
    end else
      filter_uris_backward ~dbd ~facts (main, other_constants) uris
  in
  let rec aux = function
    | [] -> []
    | uri :: tl ->
        (let status' =
            try
              let (subst,(proof, goal_list)) =
                  (* prerr_endline ("STO APPLICANDO" ^ uri); *)
                  PrimitiveTactics.apply_tac_verbose 
		    ~term:(CicUtil.term_of_uri uri)
                  status
              in
              let goal_list =
                List.stable_sort (compare_goal_list proof) goal_list
              in
              Some (uri, (subst,(proof, goal_list)))
            with ProofEngineTypes.Fail _ -> None
          in
          match status' with
          | None -> aux tl
          | Some status' -> status' :: aux tl)
  in
  List.stable_sort
    (fun (_,(_, (_, goals1))) (_,(_, (_, goals2))) ->
      Pervasives.compare (List.length goals1) (List.length goals2))
    (aux uris)

let elim ~dbd uri =
  let constraints =
    [`Rel [`MainConclusion None];
     `Sort (Cic.Prop,[`MainHypothesis (Some 1)]);
     `Obj (uri,[`MainHypothesis (Some 0)]);
     `Obj (uri,[`InHypothesis]);
    ]
  in
  MetadataConstraints.at_least ~dbd constraints