(* $Id$ *)

open Util
open Pp
open Options
open Names
open Environ
open Libobject
open Declare
open Term
open Rawterm

(* usage qque peu general: utilise aussi dans record *)

type cte_typ = 
  | NAM_Var of identifier
  | NAM_Constant of section_path
  | NAM_Inductive of inductive_path
  | NAM_Constructor of constructor_path

let cte_of_constr c = match kind_of_term c with
  | IsConst (sp,_) -> NAM_Constant sp
  | IsMutInd (ind_sp,_) -> NAM_Inductive ind_sp
  | IsMutConstruct (cstr_cp,_) -> NAM_Constructor cstr_cp
  | IsVar id -> NAM_Var id
  |  _ -> raise Not_found

type cl_typ = 
  | CL_SORT 
  | CL_FUN
  | CL_Var of identifier
  | CL_SP of section_path 
  | CL_IND of inductive_path

type cl_info_typ = {
  cL_STR : string;
  cL_STRE : strength;
  cL_PARAM : int }

type coe_typ = cte_typ

type coe_info_typ = {
  cOE_VALUE : unsafe_judgment;
  cOE_STRE : strength;
  cOE_ISID : bool;
  cOE_PARAM : int }

type inheritance_path = int list


(* table des classes, des coercions et graphe d'heritage *)

let cLASSES = (ref [] : (int * (cl_typ * cl_info_typ)) list ref)

let classes () = !cLASSES

let cOERCIONS = (ref [] : (int * (coe_typ * coe_info_typ)) list ref)

let coercions () = !cOERCIONS

let iNHERITANCE_GRAPH = (ref [] : ((int * int) * inheritance_path) list ref) 

let inheritance_graph () = !iNHERITANCE_GRAPH

let freeze () = (!cLASSES,!cOERCIONS, !iNHERITANCE_GRAPH)

let unfreeze (fcl,fco,fig) = 
  cLASSES:=fcl;
  cOERCIONS:=fco;
  iNHERITANCE_GRAPH:=fig

(* ajout de nouveaux "objets" *)

let newNum_class = 
 let num = ref 0 in
 function () -> (num:=!num+1;!num)

let newNum_coercion = 
 let num = ref 0 in
 function () -> (num:=!num+1;!num)

let add_new_class_num (n,(cl,s)) = 
  cLASSES := (n,(cl,s))::(!cLASSES)

let add_new_class1 (cl,s) = 
  add_new_class_num (newNum_class(),(cl,s))

let add_new_coercion_num (n,(coe,s)) = 
  cOERCIONS := (n,(coe,s))::(!cOERCIONS)

let add_new_coercion (coe,s) = 
  let n = newNum_coercion() in 
  add_new_coercion_num (n,(coe,s));n

let add_new_path x =
  iNHERITANCE_GRAPH := x::(!iNHERITANCE_GRAPH)

let init () =
  cLASSES:= []; 
  add_new_class1 (CL_FUN,{cL_STR="FUNCLASS";
			  cL_PARAM=0;cL_STRE=NeverDischarge});
  add_new_class1 (CL_SORT,{cL_STR="SORTCLASS";
			   cL_PARAM=0;cL_STRE=NeverDischarge});
  cOERCIONS:= [];
  iNHERITANCE_GRAPH:= []

let _ = init()

(* fonction de recherche *)

let search_info x l = 
  let rec aux = function 
    | [] -> raise Not_found
    | (n,(x1,r))::l -> if x=x1 then (n,r) else aux l
  in 
  aux l

(* class_info : cl_typ -> int * cl_info_typ *)

let class_info cl = search_info cl (!cLASSES)

let class_exists cl =
  try let _ = class_info cl in true
  with Not_found -> false

(* class_info_from_index : int -> cl_typ * cl_info_typ *)

let class_info_from_index i = List.assoc i (!cLASSES)

(* coercion_info : coe_typ -> int * coe_info_typ *)

let coercion_info coe = search_info coe (!cOERCIONS)

let coercion_exists coe =
  try let _ = coercion_info coe in true
  with Not_found -> false

let coe_of_reference = function
  | RConst (sp,l) -> NAM_Constant sp
  | RInd (ind_sp,l) -> NAM_Inductive ind_sp
  | RConstruct (cstr_sp,l) -> NAM_Constructor cstr_sp
  | RVar id  -> NAM_Var id
  | _ -> raise Not_found

let coercion_params r =
  let _,coe_info = coercion_info (coe_of_reference r) in
  coe_info.cOE_PARAM

(* coercion_info_from_index : int -> coe_typ * coe_info_typ *)

let coercion_info_from_index i = 
  List.assoc i (!cOERCIONS)

let lookup_path_between (s,t) =
  List.assoc (s,t) (!iNHERITANCE_GRAPH)

let lookup_path_to_fun_from s = 
  lookup_path_between (s,fst(class_info CL_FUN))

let lookup_path_to_sort_from s = 
  lookup_path_between (s,fst(class_info CL_SORT))

(* library, summary *)

(*val inClass : (cl_typ * cl_info_typ) -> Libobject.object = <fun>
 val outClass : Libobject.object -> (cl_typ * cl_info_typ) = <fun> *)

let cache_class (_,x) = add_new_class1 x

let (inClass,outClass) =
  declare_object ("CLASS",
                  { load_function = (fun _ -> ());
		    open_function = cache_class;
                    cache_function = cache_class;
                    specification_function = (function x -> x) })

let add_new_class (cl,s,stre,p) = 
  Lib.add_anonymous_leaf (inClass ((cl,{cL_STR=s;cL_STRE=stre;cL_PARAM=p})))
   
let _ = 
  Summary.declare_summary "inh_graph"
    { Summary.freeze_function = freeze;
      Summary.unfreeze_function = unfreeze;
      Summary.init_function = init }

(* classe d'un terme *)

(* constructor_at_head : constr -> cl_typ * int *)

let constructor_at_head t = 
  let rec aux t' = match kind_of_term t' with
    | IsVar id -> CL_Var id,0
    | IsConst (sp,_) -> CL_SP sp,0
    | IsMutInd (ind_sp,_) -> CL_IND ind_sp,0
    | IsProd (_,_,c) -> CL_FUN,0
    | IsLetIn (_,_,_,c) -> aux c
    | IsSort _ -> CL_SORT,0
    | IsCast (c,_) -> aux (collapse_appl c)
    | IsApp (f,args) -> let c,_ = aux f in c, Array.length args
    |  _ -> raise Not_found
  in 
  aux (collapse_appl t)

(* class_of : Term.constr -> int *)

let class_of env sigma t = 
  let t,n,n1,i = 
    (try 
       let (cl,n) = constructor_at_head t in
       let (i,{cL_PARAM=n1}) = class_info cl in
       t,n,n1,i              
     with _ -> 
       let t = Tacred.hnf_constr env sigma t in
       let (cl,n) = constructor_at_head t in
       let (i,{cL_PARAM=n1}) = class_info cl in
       t,n,n1,i) 
  in
  if n = n1 then t,i else raise Not_found

let class_args_of c = snd (decomp_app c)

(* verfications pour l'ajout d'une classe *)

let fully_applied id p p1 =
  if p <> p1 then  errorlabstrm "fully_applied" 
    [< 'sTR"Wrong number of parameters for ";'sTR(string_of_id id) >]

let rec arity_sort a = match kind_of_term a with
  | IsSort (Prop _ | Type _) -> 0
  | IsProd (_,_,c) -> (arity_sort c) +1
  | IsLetIn (_,_,_,c) -> arity_sort c    (* Utile ?? *)
  | IsCast (c,_) -> arity_sort c
  | _ -> raise Not_found

let stre_of_cl = function 
  | CL_SP sp ->
      if is_constant sp then constant_or_parameter_strength sp
      else NeverDischarge
  | CL_Var id -> 
      variable_strength id
  | _ -> NeverDischarge

(* coe_value : int -> Term.constr * bool *)

let coe_value i = 
  let (_,{cOE_VALUE=v;cOE_ISID=b}) = coercion_info_from_index i in
  v,b

(* pretty-print functions are now in Pretty *)
(* rajouter une coercion dans le graphe *)

let path_printer = ref (fun _ -> [< 'sTR "<a class path>" >] 
                        : (int * int) * inheritance_path -> std_ppcmds)

let install_path_printer f = path_printer := f
 
let print_path x = !path_printer x

let message_ambig l = 
  [< 'sTR"Ambiguous paths:"; 'sPC;
     prlist_with_sep pr_fnl (fun ijp -> print_path ijp) l >]

(* add_coercion_in_graph : int * int * int -> unit 
                         coercion,source,target *)

let add_coercion_in_graph (ic,source,target) =
  let old_iNHERITANCE_GRAPH = !iNHERITANCE_GRAPH in
  let ambig_paths = (ref []:((int * int) * inheritance_path) list ref) in
  let try_add_new_path (p,i,j) =
    try 
      if i=j then begin
	if (snd (class_info_from_index i)).cL_PARAM > 0 then begin
	  let _ = lookup_path_between (i,j) in
          ambig_paths := ((i,j),p)::!ambig_paths
	end
      end else begin
        let _ = lookup_path_between (i,j) in
        ambig_paths := ((i,j),p)::!ambig_paths
      end;
      false
    with Not_found -> begin
      add_new_path ((i,j),p);
      true
    end
  in
  let try_add_new_path1 (p,i,j) = 
    let _ = try_add_new_path (p,i,j) in () 
  in
  if try_add_new_path ([ic],source,target) then begin
    List.iter 
      (fun ((s,t),p) ->
         if s<>t then begin
	   if t = source then begin
             try_add_new_path1 (p @ [ ic ],s,target);
             List.iter 
	       (fun ((u,v),q) ->
                  if u<>v & (u = target) & (p <> q) then 
		    try_add_new_path1 (p @ [ ic ] @ q,s,v))
               old_iNHERITANCE_GRAPH
           end;
           if s = target then try_add_new_path1 (ic::p,source,t)
	 end)
      old_iNHERITANCE_GRAPH 
  end;
  if (!ambig_paths <> []) & is_mes_ambig() then 
    pPNL (message_ambig !ambig_paths)

let add_new_coercion_in_graph ((coef,xf),cls,clt) =
  let is,_ = class_info cls in
  let it,_ = class_info clt in
  let jf = add_new_coercion (coef,xf) in
  add_coercion_in_graph (jf,is,it)

(* val inCoercion : (coe_typ * coe_info_typ) * cl_typ * cl_typ  ->
                    -> Libobject.object 
   val outCoercion : Libobject.object -> (coe_typ * coe_info_typ) 
                         * cl_typ * cl_typ *)

let cache_coercion (_,x) = add_new_coercion_in_graph x

let (inCoercion,outCoercion) =
  declare_object ("COERCION",
                  { load_function = (fun _ -> ());
		    open_function = cache_coercion;
                    cache_function = cache_coercion;
                    specification_function = (function x -> x) })