open Printer
open Pp
open Names
open Constr
open Context
open Vars
open Glob_term
open Glob_ops
open Indfun_common
open CErrors
open Util
open Glob_termops
module RelDecl = Context.Rel.Declaration
module NamedDecl = Context.Named.Declaration
module ERelevance = EConstr.ERelevance

let observe strm = if do_observe () then Feedback.msg_debug strm else ()

(*let observennl strm =
  if do_observe ()
  then Pp.msg strm
  else ()*)

type binder_type = Lambda of Name.t | Prod of Name.t | LetIn of Name.t
type glob_context = (binder_type * glob_constr) list

let rec solve_trivial_holes pat_as_term e =
  match (DAst.get pat_as_term, DAst.get e) with
  | GHole _, _ -> e
  | GApp (fp, argsp), GApp (fe, argse) when glob_constr_eq fp fe ->
    DAst.make
      (GApp
         (solve_trivial_holes fp fe, List.map2 solve_trivial_holes argsp argse))
  | _, _ -> pat_as_term

(*
   compose_glob_context [(bt_1,n_1,t_1);......] rt returns
   b_1(n_1,t_1,.....,bn(n_k,t_k,rt)) where the b_i's are the
   binders corresponding to the bt_i's
*)
let compose_glob_context =
  let compose_binder (bt, t) acc =
    match bt with
    | Lambda n -> mkGLambda (n, t, acc)
    | Prod n -> mkGProd (n, t, acc)
    | LetIn n -> mkGLetIn (n, t, None, acc)
  in
  List.fold_right compose_binder

(*
   The main part deals with building a list of globalized constructor expressions
   from the rhs of a fixpoint equation.
*)

type 'a build_entry_pre_return =
  { context : glob_context
  ; (* the binding context of the result *)
    value : 'a (* The value *) }

type 'a build_entry_return =
  {result : 'a build_entry_pre_return list; to_avoid : Id.t list}

(*
  [combine_results combine_fun res1 res2] combine two results [res1] and [res2]
  w.r.t. [combine_fun].

  Informally, both [res1] and [res2] are lists of "constructors"  [res1_1;...]
  and [res2_1,....] and we need to produce
  [combine_fun res1_1 res2_1;combine_fun res1_1 res2_2;........]
*)

let combine_results
    (combine_fun :
         'a build_entry_pre_return
      -> 'b build_entry_pre_return
      -> 'c build_entry_pre_return) (res1 : 'a build_entry_return)
    (res2 : 'b build_entry_return) : 'c build_entry_return =
  let pre_result =
    List.map
      (fun res1 ->
        (* for each result in arg_res *)
        List.map (* we add it in each args_res *)
          (fun res2 -> combine_fun res1 res2)
          res2.result)
      res1.result
  in
  (* and then we flatten the map *)
  { result = List.concat pre_result
  ; to_avoid = List.union Id.equal res1.to_avoid res2.to_avoid }

(*
   The combination function for an argument with a list of argument
*)

let combine_args arg args =
  { context = arg.context @ args.context
  ; (* Note that the binding context of [arg] MUST be placed before the one of
       [args] in order to preserve possible type dependencies
    *)
    value = arg.value :: args.value }

let ids_of_binder = function
  | LetIn Anonymous | Prod Anonymous | Lambda Anonymous -> Id.Set.empty
  | LetIn (Name id) | Prod (Name id) | Lambda (Name id) -> Id.Set.singleton id

let rec change_vars_in_binder mapping = function
  | [] -> []
  | (bt, t) :: l ->
    let new_mapping = Id.Set.fold Id.Map.remove (ids_of_binder bt) mapping in
    (bt, change_vars mapping t)
    ::
    ( if Id.Map.is_empty new_mapping then l
    else change_vars_in_binder new_mapping l )

let rec replace_var_by_term_in_binder x_id term = function
  | [] -> []
  | (bt, t) :: l ->
    (bt, replace_var_by_term x_id term t)
    ::
    ( if Id.Set.mem x_id (ids_of_binder bt) then l
    else replace_var_by_term_in_binder x_id term l )

let add_bt_names bt = Id.Set.union (ids_of_binder bt)

let apply_args ctxt body args =
  let need_convert_id avoid id =
    List.exists (is_free_in id) args || Id.Set.mem id avoid
  in
  let need_convert avoid bt =
    Id.Set.exists (need_convert_id avoid) (ids_of_binder bt)
  in
  let next_name_away (na : Name.t) (mapping : Id.t Id.Map.t) (avoid : Id.Set.t)
      =
    match na with
    | Name id when Id.Set.mem id avoid ->
      let new_id = Namegen.next_ident_away id avoid in
      (Name new_id, Id.Map.add id new_id mapping, Id.Set.add new_id avoid)
    | _ -> (na, mapping, avoid)
  in
  let next_bt_away bt (avoid : Id.Set.t) =
    match bt with
    | LetIn na ->
      let new_na, mapping, new_avoid = next_name_away na Id.Map.empty avoid in
      (LetIn new_na, mapping, new_avoid)
    | Prod na ->
      let new_na, mapping, new_avoid = next_name_away na Id.Map.empty avoid in
      (Prod new_na, mapping, new_avoid)
    | Lambda na ->
      let new_na, mapping, new_avoid = next_name_away na Id.Map.empty avoid in
      (Lambda new_na, mapping, new_avoid)
  in
  let rec do_apply avoid ctxt body args =
    match (ctxt, args) with
    | _, [] ->
      (* No more args *)
      (ctxt, body)
    | [], _ ->
      (* no more fun *)
      let f, args' = glob_decompose_app body in
      (ctxt, mkGApp (f, args' @ args))
    | (Lambda Anonymous, t) :: ctxt', arg :: args' ->
      do_apply avoid ctxt' body args'
    | (Lambda (Name id), t) :: ctxt', arg :: args' ->
      let new_avoid, new_ctxt', new_body, new_id =
        if need_convert_id avoid id then
          let new_avoid = Id.Set.add id avoid in
          let new_id = Namegen.next_ident_away id new_avoid in
          let new_avoid' = Id.Set.add new_id new_avoid in
          let mapping = Id.Map.add id new_id Id.Map.empty in
          let new_ctxt' = change_vars_in_binder mapping ctxt' in
          let new_body = change_vars mapping body in
          (new_avoid', new_ctxt', new_body, new_id)
        else (Id.Set.add id avoid, ctxt', body, id)
      in
      let new_body = replace_var_by_term new_id arg new_body in
      let new_ctxt' = replace_var_by_term_in_binder new_id arg new_ctxt' in
      do_apply avoid new_ctxt' new_body args'
    | (bt, t) :: ctxt', _ ->
      let new_avoid, new_ctxt', new_body, new_bt =
        let new_avoid = add_bt_names bt avoid in
        if need_convert avoid bt then
          let new_bt, mapping, new_avoid = next_bt_away bt new_avoid in
          ( new_avoid
          , change_vars_in_binder mapping ctxt'
          , change_vars mapping body
          , new_bt )
        else (new_avoid, ctxt', body, bt)
      in
      let new_ctxt', new_body = do_apply new_avoid new_ctxt' new_body args in
      ((new_bt, t) :: new_ctxt', new_body)
  in
  do_apply Id.Set.empty ctxt body args

let combine_app f args =
  let new_ctxt, new_value = apply_args f.context f.value args.value in
  { (* Note that the binding context of [args] MUST be placed before the one of
       the applied value in order to preserve possible type dependencies
    *)
    context = args.context @ new_ctxt
  ; value = new_value }

let combine_lam n t b =
  { context = []
  ; value =
      mkGLambda
        ( n
        , compose_glob_context t.context t.value
        , compose_glob_context b.context b.value ) }

let combine_prod2 n t b =
  { context = []
  ; value =
      mkGProd
        ( n
        , compose_glob_context t.context t.value
        , compose_glob_context b.context b.value ) }

let combine_prod n t b =
  {context = t.context @ ((Prod n, t.value) :: b.context); value = b.value}

let combine_letin n t b =
  {context = t.context @ ((LetIn n, t.value) :: b.context); value = b.value}

let mk_result ctxt value avoid =
  {result = [{context = ctxt; value}]; to_avoid = avoid}

(*************************************************
  Some functions to deal with overlapping patterns
**************************************************)

let rocq_True_ref = lazy (Coqlib.lib_ref "core.True.type")
let rocq_False_ref = lazy (Coqlib.lib_ref "core.False.type")

(*
  [make_discr_match_el \[e1,...en\]] builds match e1,...,en with
  (the list of expressions on which we will do the matching)
 *)
let make_discr_match_el = List.map (fun e -> (e, (Anonymous, None)))

(*
  [make_discr_match_brl i \[pat_1,...,pat_n\]]  constructs a discrimination pattern matching on the ith expression.
  that is.
  match ?????? with \\
  | pat_1 => False  \\
  | pat_{i-1} => False \\
  | pat_i => True \\
  | pat_{i+1} => False \\
  \vdots
  | pat_n => False
  end
*)
let make_discr_match_brl i =
  List.map_i
    (fun j {CAst.v = idl, patl, _} ->
      CAst.make
      @@
      if Int.equal j i then (idl, patl, mkGRef (Lazy.force rocq_True_ref))
      else (idl, patl, mkGRef (Lazy.force rocq_False_ref)))
    0

(*
   [make_discr_match brl el i] generates an hypothesis such that it reduce to true iff
   brl_{i} is the first branch matched by [el]

   Used when we want to simulate the coq pattern matching algorithm
*)
let make_discr_match brl el i =
  mkGCases (None, make_discr_match_el el, make_discr_match_brl i brl)

(**********************************************************************)
(*  functions used to build case expression from lettuple and if ones *)
(**********************************************************************)

(* [build_constructors_of_type] construct the array of pattern of its inductive argument*)
let build_constructors_of_type env ind' argl =
  let mib, ind = Inductive.lookup_mind_specif env ind' in
  let npar = mib.Declarations.mind_nparams in
  Array.mapi
    (fun i _ ->
      let construct = (ind', i + 1) in
      let constructref = GlobRef.ConstructRef construct in
      let _implicit_positions_of_cst =
        Impargs.implicits_of_global constructref
      in
      let cst_narg =
        Inductiveops.constructor_nallargs env construct
      in
      let argl =
        if List.is_empty argl then List.make cst_narg (mkGHole ())
        else List.make npar (mkGHole ()) @ argl
      in
      let pat_as_term =
        mkGApp (mkGRef (GlobRef.ConstructRef (ind', i + 1)), argl)
      in
      cases_pattern_of_glob_constr env Anonymous pat_as_term)
    ind.Declarations.mind_consnames

(******************)
(* Main functions *)
(******************)

let raw_push_named (na, raw_value, raw_typ) env =
  match na with
  | Anonymous -> env
  | Name id -> (
    let typ, _ =
      Pretyping.understand env (Evd.from_env env)
        ~expected_type:Pretyping.IsType raw_typ
    in
    let na = make_annot id ERelevance.relevant in
    (* TODO relevance *)
    match raw_value with
    | None -> EConstr.push_named (NamedDecl.LocalAssum (na, typ)) env
    | Some value -> EConstr.push_named (NamedDecl.LocalDef (na, value, typ)) env
    )

let add_pat_variables sigma pat typ env : Environ.env =
  let rec add_pat_variables env pat typ : Environ.env =
    observe
      (str "new rel env := " ++ Printer.pr_rel_context_of env (Evd.from_env env));
    match DAst.get pat with
    | PatVar na ->
      EConstr.push_rel
        (RelDecl.LocalAssum (make_annot na ERelevance.relevant, typ))
        env
    | PatCstr (c, patl, na) ->
      let (Inductiveops.IndType (indf, indargs)) =
        try
          Inductiveops.find_rectype env (Evd.from_env env)
            typ
        with Not_found -> assert false
      in
      let constructors = Inductiveops.get_constructors env indf in
      let constructor : Inductiveops.constructor_summary =
        List.find
          (fun cs -> Environ.QConstruct.equal env c (fst cs.Inductiveops.cs_cstr))
          (Array.to_list constructors)
      in
      let cs_args_types : EConstr.types list =
        List.map RelDecl.get_type constructor.Inductiveops.cs_args
      in
      List.fold_left2 add_pat_variables env patl (List.rev cs_args_types)
  in
  let new_env = add_pat_variables env pat typ in
  let res =
    fst
      (Context.Rel.fold_outside
         (fun decl (env, ctxt) ->
           let open Context.Rel.Declaration in
           match decl with
           | LocalAssum ({binder_name = Anonymous}, _)
            |LocalDef ({binder_name = Anonymous}, _, _) ->
             assert false
           | LocalAssum (({binder_name = Name id} as na), t) ->
             let na = {na with binder_name = id} in
             let new_t = substl ctxt t in
             observe
               ( str "for variable " ++ Ppconstr.pr_id id ++ fnl ()
               ++ str "old type := "
               ++ Printer.pr_lconstr_env env sigma t
               ++ fnl () ++ str "new type := "
               ++ Printer.pr_lconstr_env env sigma new_t
               ++ fnl () );
             let open Context.Named.Declaration in
             (Environ.push_named (LocalAssum (na, new_t)) env, mkVar id :: ctxt)
           | LocalDef (({binder_name = Name id} as na), v, t) ->
             let na = {na with binder_name = id} in
             let new_t = substl ctxt t in
             let new_v = substl ctxt v in
             observe
               ( str "for variable " ++ Ppconstr.pr_id id ++ fnl ()
               ++ str "old type := "
               ++ Printer.pr_lconstr_env env sigma t
               ++ fnl () ++ str "new type := "
               ++ Printer.pr_lconstr_env env sigma new_t
               ++ fnl () ++ str "old value := "
               ++ Printer.pr_lconstr_env env sigma v
               ++ fnl () ++ str "new value := "
               ++ Printer.pr_lconstr_env env sigma new_v
               ++ fnl () );
             let open Context.Named.Declaration in
             ( Environ.push_named (LocalDef (na, new_v, new_t)) env
             , mkVar id :: ctxt ))
         (Environ.rel_context new_env)
         ~init:(env, []))
  in
  observe
    (str "new var env := " ++ Printer.pr_named_context_of res (Evd.from_env env));
  res

let rec pattern_to_term_and_type env typ =
  DAst.with_val (function
    | PatVar Anonymous -> assert false
    | PatVar (Name id) -> mkGVar id
    | PatCstr (constr, patternl, _) ->
      let cst_narg = Inductiveops.constructor_nallargs env constr in
      let (Inductiveops.IndType (indf, indargs)) =
        try
          Inductiveops.find_rectype env (Evd.from_env env)
            typ
        with Not_found -> assert false
      in
      let constructors = Inductiveops.get_constructors env indf in
      let constructor =
        List.find
          (fun cs ->
            Environ.QConstruct.equal env (fst cs.Inductiveops.cs_cstr) constr)
          (Array.to_list constructors)
      in
      let cs_args_types : EConstr.types list =
        List.map RelDecl.get_type constructor.Inductiveops.cs_args
      in
      let _, cstl = Inductiveops.dest_ind_family indf in
      let csta = Array.of_list cstl in
      let implicit_args =
        Array.to_list
          (Array.init
             (cst_narg - List.length patternl)
             (fun i ->
               Detyping.detype Detyping.Now env
                 (Evd.from_env env)
                 csta.(i)))
      in
      let patl_as_term =
        List.map2
          (pattern_to_term_and_type env)
          (List.rev cs_args_types) patternl
      in
      mkGApp (mkGRef (GlobRef.ConstructRef constr), implicit_args @ patl_as_term))

(* [build_entry_lc funnames avoid rt] construct the list (in fact a build_entry_return)
   of constructors corresponding to [rt] when replacing calls to [funnames] by calls to the
   corresponding graphs.


   The idea to transform a term [t] into a list of constructors [lc] is the following:
   \begin{itemize}
   \item if the term is a binder (bind x, body) then first compute [lc'] the list corresponding
   to [body] and add (bind x. _) to each elements of [lc]
   \item if the term has the form (g t1 ... ... tn) where g does not appears in (fnames)
   then compute [lc1] ... [lcn] the lists of constructors corresponding to [t1] ... [tn],
   then combine those lists and [g] as follows~: for each element [c1,...,cn] of [lc1\times...\times lcn],
   [g c1 ... cn] is an element of [lc]
   \item if the term has the form (f t1 .... tn) where [f] appears in [fnames] then
   compute [lc1] ... [lcn] the lists of constructors corresponding to [t1] ... [tn],
   then compute those lists and [f] as follows~: for each element [c1,...,cn] of [lc1\times...\times lcn]
   create a new variable [res] and [forall res, R_f c1 ... cn res] is in [lc]
   \item if the term is a cast just treat its body part
   \item
   if the term is a match, an if or a lettuple then compute the lists corresponding to each branch of the case
   and concatenate them (informally, each branch of a match produces a new constructor)
   \end{itemize}

   WARNING: The terms constructed here are only USING the glob_constr syntax but are highly bad formed.
   We must wait to have complete all the current calculi to set the recursive calls.
   At this point, each term [f t1 ... tn]  (where f appears in [funnames]) is replaced by
   a pseudo term [forall res, res t1 ... tn, res]. A reconstruction phase is done later.
   We in fact not create a constructor list since then end of each constructor has not the expected form
   but only the value of the function
*)

let pr_glob_constr_env env x = pr_glob_constr_env env (Evd.from_env env) x

let rec build_entry_lc env sigma funnames avoid rt :
    glob_constr build_entry_return =
  observe (str " Entering : " ++ pr_glob_constr_env env rt);
  let open CAst in
  match DAst.get rt with
  | GRef _ | GVar _ | GEvar _ | GPatVar _ | GSort _ | GHole _ | GGenarg _ | GInt _
   |GFloat _ | GString _ ->
    (* do nothing (except changing type of course) *)
    mk_result [] rt avoid
  | GApp (_, _) -> (
    let f, args = glob_decompose_app rt in
    let args_res : glob_constr list build_entry_return =
      List.fold_right
        (* create the arguments lists of constructors and combine them *)
          (fun arg ctxt_argsl ->
          let arg_res =
            build_entry_lc env sigma funnames ctxt_argsl.to_avoid arg
          in
          combine_results combine_args arg_res ctxt_argsl)
        args (mk_result [] [] avoid)
    in
    match DAst.get f with
    | GLambda _ ->
      let rec aux t l =
        match l with
        | [] -> t
        | u :: l -> (
          DAst.make
          @@
          match DAst.get t with
          | GLambda (na, _, _, nat, b) -> GLetIn (na, None, u, None, aux b l)
          | _ -> GApp (t, l) )
      in
      build_entry_lc env sigma funnames avoid (aux f args)
    | GVar id when Id.Set.mem id funnames ->
      (* if we have [f t1 ... tn] with [f]$\in$[fnames]
         then we create a fresh variable [res],
         add [res] and its "value" (i.e. [res v1 ... vn]) to each
         pseudo constructor build for the arguments (i.e. a pseudo context [ctxt] and
         a pseudo value "v1 ... vn".
         The "value" of this branch is then simply [res]
      *)
      (* XXX here and other [understand] calls drop the ctx *)
      let rt_as_constr, ctx = Pretyping.understand env (Evd.from_env env) rt in
      let rt_typ = Retyping.get_type_of env (Evd.from_env env) rt_as_constr in
      let res_raw_type =
        Detyping.detype Detyping.Now env (Evd.from_env env)
          rt_typ
      in
      let res = fresh_id args_res.to_avoid "_res" in
      let new_avoid = res :: args_res.to_avoid in
      let res_rt = mkGVar res in
      let new_result =
        List.map
          (fun arg_res ->
            let new_hyps =
              [ (Prod (Name res), res_raw_type)
              ; (Prod Anonymous, mkGApp (res_rt, mkGVar id :: arg_res.value)) ]
            in
            {context = arg_res.context @ new_hyps; value = res_rt})
          args_res.result
      in
      {result = new_result; to_avoid = new_avoid}
    | GVar _ | GEvar _ | GPatVar _ | GHole _ | GGenarg _ | GSort _ | GRef _ ->
      (* if have [g t1 ... tn] with [g] not appearing in [funnames]
         then
         foreach [ctxt,v1 ... vn] in [args_res] we return
         [ctxt, g v1 .... vn]
      *)
      { args_res with
        result =
          List.map
            (fun args_res -> {args_res with value = mkGApp (f, args_res.value)})
            args_res.result }
    | GApp _ ->
      assert false (* we have collected all the app in [glob_decompose_app] *)
    | GLetIn (n, _, v, t, b) ->
      (* if we have [(let x := v in b) t1 ... tn] ,
         we discard our work and compute the list of constructor for
         [let x = v in (b t1 ... tn)] up to alpha conversion
      *)
      let new_n, new_b, new_avoid =
        match n with
        | Name id when List.exists (is_free_in id) args ->
          (* need to alpha-convert the name *)
          let new_id = Namegen.next_ident_away id (Id.Set.of_list avoid) in
          let new_avoid = id :: avoid in
          let new_b = replace_var_by_term id (DAst.make @@ GVar id) b in
          (Name new_id, new_b, new_avoid)
        | _ -> (n, b, avoid)
      in
      build_entry_lc env sigma funnames avoid
        (mkGLetIn (new_n, v, t, mkGApp (new_b, args)))
    | GCases _ | GIf _ | GLetTuple _ | GProj _ ->
      (* we have [(match e1, ...., en with ..... end) t1 tn]
         we first compute the result from the case and
         then combine each of them with each of args one
      *)
      let f_res = build_entry_lc env sigma funnames args_res.to_avoid f in
      combine_results combine_app f_res args_res
    | GCast (b, _, _) ->
      (* for an applied cast we just trash the cast part
         and restart the work.

         WARNING: We need to restart since [b] itself should be an application term
      *)
      build_entry_lc env sigma funnames avoid (mkGApp (b, args))
    | GRec _ -> user_err Pp.(str "Not handled GRec")
    | GProd _ -> user_err Pp.(str "Cannot apply a type")
    | GInt _ -> user_err Pp.(str "Cannot apply an integer")
    | GFloat _ -> user_err Pp.(str "Cannot apply a float")
    | GString _ -> user_err Pp.(str "Cannot apply a string")
    | GArray _ -> user_err Pp.(str "Cannot apply an array")
    (* end of the application treatement *) )
  | GProj (f, params, c) ->
    let args_res : glob_constr list build_entry_return =
      List.fold_right
        (* create the arguments lists of constructors and combine them *)
          (fun arg ctxt_argsl ->
          let arg_res =
            build_entry_lc env sigma funnames ctxt_argsl.to_avoid arg
          in
          combine_results combine_args arg_res ctxt_argsl)
        (params@[c]) (mk_result [] [] avoid) in
      { args_res with
        result =
          List.map
            (fun args_res ->
              let c, params = List.sep_last args_res.value in
              {args_res with value = DAst.make (GProj (f, params, c))})
            args_res.result }
  | GLambda (n, _, _, t, b) ->
    (* we first compute the list of constructor
       corresponding to the body of the function,
       then the one corresponding to the type
       and combine the two result
    *)
    let t_res = build_entry_lc env sigma funnames avoid t in
    let new_n =
      match n with
      | Name _ -> n
      | Anonymous -> Name (Indfun_common.fresh_id [] "_x")
    in
    let new_env = raw_push_named (new_n, None, t) env in
    let b_res = build_entry_lc new_env sigma funnames avoid b in
    combine_results (combine_lam new_n) t_res b_res
  | GProd (n, _, _, t, b) ->
    (* we first compute the list of constructor
       corresponding to the body of the function,
       then the one corresponding to the type
       and combine the two result
    *)
    let t_res = build_entry_lc env sigma funnames avoid t in
    let new_env = raw_push_named (n, None, t) env in
    let b_res = build_entry_lc new_env sigma funnames avoid b in
    if List.length t_res.result = 1 && List.length b_res.result = 1 then
      combine_results (combine_prod2 n) t_res b_res
    else combine_results (combine_prod n) t_res b_res
  | GLetIn (n, _, v, typ, b) ->
    (* we first compute the list of constructor
       corresponding to the body of the function,
       then the one corresponding to the value [t]
       and combine the two result
    *)
    let v =
      match typ with
      | None -> v
      | Some t -> DAst.make ?loc:rt.loc @@ GCast (v, Some DEFAULTcast, t)
    in
    let v_res = build_entry_lc env sigma funnames avoid v in
    let v_as_constr, ctx = Pretyping.understand env (Evd.from_env env) v in
    let v_type = Retyping.get_type_of env (Evd.from_env env) v_as_constr in
    let v_r = ERelevance.relevant in
    (* TODO relevance *)
    let new_env =
      match n with
      | Anonymous -> env
      | Name id ->
        EConstr.push_named
          (NamedDecl.LocalDef (make_annot id v_r, v_as_constr, v_type))
          env
    in
    let b_res = build_entry_lc new_env sigma funnames avoid b in
    combine_results (combine_letin n) v_res b_res
  | GCases (_, _, el, brl) ->
    (* we create the discrimination function
       and treat the case itself
    *)
    let make_discr = make_discr_match brl in
    build_entry_lc_from_case env sigma funnames make_discr el brl avoid
  | GIf (b, (na, e_option), lhs, rhs) ->
    let b_as_constr, ctx = Pretyping.understand env (Evd.from_env env) b in
    let b_typ = Retyping.get_type_of env (Evd.from_env env) b_as_constr in
    let ind, _ =
      try Inductiveops.find_inductive env (Evd.from_env env) b_typ
      with Not_found ->
        user_err
          ( str "Cannot find the inductive associated to "
          ++ pr_glob_constr_env env b ++ str " in " ++ pr_glob_constr_env env rt
          ++ str ". try again with a cast" )
    in
    let case_pats = build_constructors_of_type env (fst ind) [] in
    assert (Int.equal (Array.length case_pats) 2);
    let brl =
      List.map_i (fun i x -> CAst.make ([], [case_pats.(i)], x)) 0 [lhs; rhs]
    in
    let match_expr = mkGCases (None, [(b, (Anonymous, None))], brl) in
    (* 		Pp.msgnl (str "new case := " ++ Printer.pr_glob_constr match_expr); *)
    build_entry_lc env sigma funnames avoid match_expr
  | GLetTuple (nal, _, b, e) ->
    let nal_as_glob_constr =
      List.map (function Name id -> mkGVar id | Anonymous -> mkGHole ()) nal
    in
    let b_as_constr, ctx = Pretyping.understand env (Evd.from_env env) b in
    let b_typ = Retyping.get_type_of env (Evd.from_env env) b_as_constr in
    let ind, _ =
      try Inductiveops.find_inductive env (Evd.from_env env) b_typ
      with Not_found ->
        user_err
          ( str "Cannot find the inductive associated to "
          ++ pr_glob_constr_env env b ++ str " in " ++ pr_glob_constr_env env rt
          ++ str ". try again with a cast" )
    in
    let case_pats = build_constructors_of_type env (fst ind) nal_as_glob_constr in
    assert (Int.equal (Array.length case_pats) 1);
    let br = CAst.make ([], [case_pats.(0)], e) in
    let match_expr = mkGCases (None, [(b, (Anonymous, None))], [br]) in
    build_entry_lc env sigma funnames avoid match_expr
  | GRec _ -> user_err Pp.(str "Not handled GRec")
  | GCast (b, _, _) -> build_entry_lc env sigma funnames avoid b
  | GArray _ -> user_err Pp.(str "Not handled GArray")

and build_entry_lc_from_case env sigma funname make_discr (el : tomatch_tuples)
    (brl : Glob_term.cases_clauses) avoid : glob_constr build_entry_return =
  match el with
  | [] -> assert false (* this case correspond to match <nothing> with .... !*)
  | el ->
    (* this case correspond to
       match el with brl end
       we first compute the list of lists corresponding to [el] and
       combine them .
       Then for each element of the combinations,
       we compute the result we compute one list per branch in [brl] and
       finally we just concatenate those list
    *)
    let case_resl =
      List.fold_right
        (fun (case_arg, _) ctxt_argsl ->
          let arg_res =
            build_entry_lc env sigma funname ctxt_argsl.to_avoid case_arg
          in
          combine_results combine_args arg_res ctxt_argsl)
        el (mk_result [] [] avoid)
    in
    let types =
      List.map
        (fun (case_arg, _) ->
          let case_arg_as_constr, ctx =
            Pretyping.understand env (Evd.from_env env) case_arg
          in
          Retyping.get_type_of env (Evd.from_env env) case_arg_as_constr)
        el
    in
    (****** The next works only if the match is not dependent ****)
    let results =
      List.map
        (fun ca ->
          let res =
            build_entry_lc_from_case_term env sigma types funname make_discr []
              brl case_resl.to_avoid ca
          in
          res)
        case_resl.result
    in
    { result = List.concat (List.map (fun r -> r.result) results)
    ; to_avoid =
        List.fold_left
          (fun acc r -> List.union Id.equal acc r.to_avoid)
          [] results }

and build_entry_lc_from_case_term env sigma types funname make_discr
    patterns_to_prevent brl avoid matched_expr =
  match brl with
  | [] -> (* computed_branches  *) {result = []; to_avoid = avoid}
  | br :: brl' ->
    (* alpha conversion to prevent name clashes *)
    let {CAst.v = idl, patl, return} = alpha_br avoid br in
    let new_avoid = idl @ avoid in
    (* for now we can no more use idl as an identifier *)
    (* building a list of precondition stating that we are not in this branch
       (will be used in the following recursive calls)
    *)
    let new_env = List.fold_right2 (add_pat_variables sigma) patl types env in
    let not_those_patterns : (Id.t list -> glob_constr -> glob_constr) list =
      List.map2
        (fun pat typ avoid pat'_as_term ->
          let renamed_pat, _, _ = alpha_pat avoid pat in
          let pat_ids = get_pattern_id renamed_pat in
          let env_with_pat_ids = add_pat_variables sigma pat typ new_env in
          List.fold_right
            (fun id acc ->
              let typ_of_id = Typing.type_of_variable env_with_pat_ids id in
              let raw_typ_of_id =
                Detyping.detype Detyping.Now env_with_pat_ids
                  (Evd.from_env env) typ_of_id
              in
              mkGProd (Name id, raw_typ_of_id, acc))
            pat_ids
            (glob_make_neq pat'_as_term (pattern_to_term renamed_pat)))
        patl types
    in
    (* Checking if we can be in this branch
       (will be used in the following recursive calls)
    *)
    let unify_with_those_patterns : (cases_pattern -> bool * bool) list =
      List.map
        (fun pat pat' -> (are_unifiable env pat pat', eq_cases_pattern env pat pat'))
        patl
    in
    (*
           we first compute the other branch result (in ordrer to keep the order of the matching
           as much as possible)
        *)
    let brl'_res =
      build_entry_lc_from_case_term env sigma types funname make_discr
        ((unify_with_those_patterns, not_those_patterns) :: patterns_to_prevent)
        brl' avoid matched_expr
    in
    (* We now create the precondition of this branch i.e.
       1- the list of variable appearing in the different patterns of this branch and
          the list of equation stating than el = patl (List.flatten ...)
       2- If there exists a previous branch which pattern unify with the one of this branch
          then a discrimination precond stating that we are not in a previous branch (if List.exists ...)
    *)
    let those_pattern_preconds =
      List.flatten
        (List.map3
           (fun pat e typ_as_constr ->
             let this_pat_ids = ids_of_pat pat in
             let typ =
               Detyping.detype Detyping.Now new_env
                 (Evd.from_env env) typ_as_constr
             in
             let pat_as_term = pattern_to_term pat in
             (* removing trivial holes *)
             let pat_as_term = solve_trivial_holes pat_as_term e in
             (* observe (str "those_pattern_preconds" ++ spc () ++ *)
             (*            str "pat" ++ spc () ++ pr_glob_constr pat_as_term ++ spc ()++ *)
             (*            str "e" ++ spc () ++ pr_glob_constr e ++spc ()++ *)
             (*            str "typ_as_constr" ++ spc () ++ pr_lconstr typ_as_constr); *)
             List.fold_right
               (fun id acc ->
                 if Id.Set.mem id this_pat_ids then
                   ( Prod (Name id)
                   , let typ_of_id = Typing.type_of_variable new_env id in
                     let raw_typ_of_id =
                       Detyping.detype Detyping.Now new_env
                         (Evd.from_env env) typ_of_id
                     in
                     raw_typ_of_id )
                   :: acc
                 else acc)
               idl
               [(Prod Anonymous, glob_make_eq ~typ pat_as_term e)])
           patl matched_expr.value types)
      @
      if
        List.exists
          (function
            | unifl, _ ->
              let unif, _ =
                List.split (List.map2 (fun x y -> x y) unifl patl)
              in
              List.for_all (fun x -> x) unif)
          patterns_to_prevent
      then
        let i = List.length patterns_to_prevent in
        let pats_as_constr =
          List.map2 (pattern_to_term_and_type new_env) types patl
        in
        [(Prod Anonymous, make_discr pats_as_constr i)]
      else []
    in
    (* We compute the result of the value returned by the branch*)
    let return_res = build_entry_lc new_env sigma funname new_avoid return in
    (* and combine it with the preconds computed for this branch *)
    let this_branch_res =
      List.map
        (fun res ->
          { context = matched_expr.context @ those_pattern_preconds @ res.context
          ; value = res.value })
        return_res.result
    in
    {brl'_res with result = this_branch_res @ brl'_res.result}

let is_res r =
  match DAst.get r with
  | GVar id -> (
    try String.equal (String.sub (Id.to_string id) 0 4) "_res"
    with Invalid_argument _ -> false )
  | _ -> false

let is_gr env c gr =
  match DAst.get c with GRef (r, _) -> Environ.QGlobRef.equal env r gr | _ -> false

let is_gvar c = match DAst.get c with GVar id -> true | _ -> false

let same_raw_term env rt1 rt2 =
  match (DAst.get rt1, DAst.get rt2) with
  | GRef (r1, _), GRef (r2, _) -> Environ.QGlobRef.equal env r1 r2
  | GHole _, GHole _ -> true
  | _ -> false

let decompose_raw_eq env lhs rhs =
  let rec decompose_raw_eq lhs rhs acc =
    observe
      ( str "decomposing eq for " ++ pr_glob_constr_env env lhs ++ str " "
      ++ pr_glob_constr_env env rhs );
    let rhd, lrhs = glob_decompose_app rhs in
    let lhd, llhs = glob_decompose_app lhs in
    observe (str "lhd := " ++ pr_glob_constr_env env lhd);
    observe (str "rhd := " ++ pr_glob_constr_env env rhd);
    observe (str "llhs := " ++ int (List.length llhs));
    observe (str "lrhs := " ++ int (List.length lrhs));
    let sllhs = List.length llhs in
    let slrhs = List.length lrhs in
    if same_raw_term env lhd rhd && Int.equal sllhs slrhs then
      (* let _ = assert false in  *)
      List.fold_right2 decompose_raw_eq llhs lrhs acc
    else (lhs, rhs) :: acc
  in
  decompose_raw_eq lhs rhs []

exception Continue

(*
   The second phase which reconstruct the real type of the constructor.
   rebuild the globalized constructors expression.
   eliminates some meaningless equalities, applies some rewrites......
*)
let rec rebuild_cons env nb_args relname args crossed_types depth rt =
  observe (str "rebuilding : " ++ pr_glob_constr_env env rt);
  let open Context.Rel.Declaration in
  let open CAst in
  match DAst.get rt with
  | GProd (n, _, k, t, b) -> (
    let not_free_in_t id = not (is_free_in id t) in
    let new_crossed_types = t :: crossed_types in
    match DAst.get t with
    | GApp (res_rt, args') when is_res res_rt -> (
      let arg = List.hd args' in
      match DAst.get arg with
      | GVar this_relname ->
        (*i The next call to mk_rel_id is
          valid since we are constructing the graph
          Ensures by: obvious
          i*)
        let new_t =
          mkGApp (mkGVar (mk_rel_id this_relname), List.tl args' @ [res_rt])
        in
        let t', ctx = Pretyping.understand env (Evd.from_env env) new_t in
        let r = ERelevance.relevant in
        (* TODO relevance *)
        let new_env = EConstr.push_rel (LocalAssum (make_annot n r, t')) env in
        let new_b, id_to_exclude =
          rebuild_cons new_env nb_args relname args new_crossed_types
            (depth + 1) b
        in
        (mkGProd (n, new_t, new_b), Id.Set.filter not_free_in_t id_to_exclude)
      | _ ->
        (* the first args is the name of the function! *)
        assert false )
    | GApp (eq_as_ref, [ty; id; rt])
      when is_gvar id
           && is_gr env eq_as_ref Coqlib.(lib_ref "core.eq.type")
           && n == Anonymous -> (
      let loc1 = rt.CAst.loc in
      let loc2 = eq_as_ref.CAst.loc in
      let loc3 = id.CAst.loc in
      let id = match DAst.get id with GVar id -> id | _ -> assert false in
      try
        observe (str "computing new type for eq : " ++ pr_glob_constr_env env rt);
        let t' =
          try fst (Pretyping.understand env (Evd.from_env env) t) (*FIXME*)
          with e when CErrors.noncritical e -> raise Continue
        in
        let is_in_b = is_free_in id b in
        let _keep_eq =
          (not (List.exists (is_free_in id) args))
          || is_in_b
          || List.exists (is_free_in id) crossed_types
        in
        let new_args = List.map (replace_var_by_term id rt) args in
        let subst_b = if is_in_b then b else replace_var_by_term id rt b in
        let r = ERelevance.relevant in
        (* TODO relevance *)
        let new_env = EConstr.push_rel (LocalAssum (make_annot n r, t')) env in
        let new_b, id_to_exclude =
          rebuild_cons new_env nb_args relname new_args new_crossed_types
            (depth + 1) subst_b
        in
        (mkGProd (n, t, new_b), id_to_exclude)
      with Continue ->
        let jmeq = GlobRef.IndRef (fst (EConstr.destInd Evd.empty (jmeq ()))) in
        let ty', ctx = Pretyping.understand env (Evd.from_env env) ty in
        let ind, args' =
          Inductiveops.find_inductive env Evd.(from_env env) ty'
        in
        let mib, _ = Inductive.lookup_mind_specif env (fst ind) in
        let nparam = mib.Declarations.mind_nparams in
        let params, arg' = Util.List.chop nparam args' in
        let rt_typ =
          DAst.make
          @@ GApp
               ( DAst.make @@ GRef (GlobRef.IndRef (fst ind), None)
               , List.map
                   (fun p ->
                     Detyping.detype Detyping.Now env
                       (Evd.from_env env) p)
                   params
                 @ Array.to_list
                     (Array.make (List.length args' - nparam) (mkGHole ())) )
        in
        let eq' =
          DAst.make ?loc:loc1
          @@ GApp
               ( DAst.make ?loc:loc2 @@ GRef (jmeq, None)
               , [ty; DAst.make ?loc:loc3 @@ GVar id; rt_typ; rt] )
        in
        observe
          (str "computing new type for jmeq : " ++ pr_glob_constr_env env eq');
        let eq'_as_constr, ctx =
          Pretyping.understand env (Evd.from_env env) eq'
        in
        observe (str " computing new type for jmeq : done");
        let sigma = Evd.(from_env env) in
        let new_args =
          match EConstr.kind sigma eq'_as_constr with
          | App (_, [|_; _; ty; _|]) ->
            let ty = Array.to_list (snd (EConstr.destApp sigma ty)) in
            let ty' = snd (Util.List.chop nparam ty) in
            List.fold_left2
              (fun acc var_as_constr arg ->
                if EConstr.isRel sigma var_as_constr then
                  let na =
                    RelDecl.get_name
                      (Environ.lookup_rel (EConstr.destRel sigma var_as_constr) env)
                  in
                  match na with
                  | Anonymous -> acc
                  | Name id' ->
                    ( id'
                    , Detyping.detype Detyping.Now env
                        (Evd.from_env env) arg )
                    :: acc
                else if EConstr.isVar sigma var_as_constr then
                  (EConstr.destVar sigma var_as_constr
                  , Detyping.detype Detyping.Now env
                      (Evd.from_env env) arg )
                  :: acc
                else acc)
              [] arg' ty'
          | _ -> assert false
        in
        let is_in_b = is_free_in id b in
        let _keep_eq =
          (not (List.exists (is_free_in id) args))
          || is_in_b
          || List.exists (is_free_in id) crossed_types
        in
        let new_args =
          List.fold_left
            (fun args (id, rt) -> List.map (replace_var_by_term id rt) args)
            args ((id, rt) :: new_args)
        in
        let subst_b = if is_in_b then b else replace_var_by_term id rt b in
        let new_env =
          let t', ctx = Pretyping.understand env (Evd.from_env env) eq' in
          let r = ERelevance.relevant in
          (* TODO relevance *)
          EConstr.push_rel (LocalAssum (make_annot n r, t')) env
        in
        let new_b, id_to_exclude =
          rebuild_cons new_env nb_args relname new_args new_crossed_types
            (depth + 1) subst_b
        in
        (mkGProd (n, eq', new_b), id_to_exclude)
      (* J.F:. keep this comment  it explain how to remove some meaningless equalities
         if keep_eq then
         mkGProd(n,t,new_b),id_to_exclude
         else new_b, Id.Set.add id id_to_exclude
      *) )
    | GApp (eq_as_ref, [ty; rt1; rt2])
      when is_gr env eq_as_ref Coqlib.(lib_ref "core.eq.type") && n == Anonymous
      -> (
      try
        let l = decompose_raw_eq env rt1 rt2 in
        if List.length l > 1 then
          let new_rt =
            List.fold_left
              (fun acc (lhs, rhs) ->
                mkGProd
                  ( Anonymous
                  , mkGApp
                      ( mkGRef Coqlib.(lib_ref "core.eq.type")
                      , [mkGHole (); lhs; rhs] )
                  , acc ))
              b l
          in
          rebuild_cons env nb_args relname args crossed_types depth new_rt
        else raise Continue
      with Continue -> (
        observe
          (str "computing new type for prod : " ++ pr_glob_constr_env env rt);
        let t', ctx = Pretyping.understand env (Evd.from_env env) t in
        let r = ERelevance.relevant in
        (* TODO relevance *)
        let new_env = EConstr.push_rel (LocalAssum (make_annot n r, t')) env in
        let new_b, id_to_exclude =
          rebuild_cons new_env nb_args relname args new_crossed_types
            (depth + 1) b
        in
        match n with
        | Name id when Id.Set.mem id id_to_exclude && depth >= nb_args ->
          (new_b, Id.Set.remove id (Id.Set.filter not_free_in_t id_to_exclude))
        | _ -> (mkGProd (n, t, new_b), Id.Set.filter not_free_in_t id_to_exclude) )
      )
    | _ -> (
      observe (str "computing new type for prod : " ++ pr_glob_constr_env env rt);
      let t', ctx = Pretyping.understand env (Evd.from_env env) t in
      let r = ERelevance.relevant in
      (* TODO relevance *)
      let new_env = EConstr.push_rel (LocalAssum (make_annot n r, t')) env in
      let new_b, id_to_exclude =
        rebuild_cons new_env nb_args relname args new_crossed_types (depth + 1)
          b
      in
      match n with
      | Name id when Id.Set.mem id id_to_exclude && depth >= nb_args ->
        (new_b, Id.Set.remove id (Id.Set.filter not_free_in_t id_to_exclude))
      | _ -> (mkGProd (n, t, new_b), Id.Set.filter not_free_in_t id_to_exclude)
      ) )
  | GLambda (n, _, k, t, b) -> (
    let not_free_in_t id = not (is_free_in id t) in
    let new_crossed_types = t :: crossed_types in
    observe (str "computing new type for lambda : " ++ pr_glob_constr_env env rt);
    let t', ctx = Pretyping.understand env (Evd.from_env env) t in
    match n with
    | Name id ->
      let r = ERelevance.relevant in
      (* TODO relevance *)
      let new_env = EConstr.push_rel (LocalAssum (make_annot n r, t')) env in
      let new_b, id_to_exclude =
        rebuild_cons new_env nb_args relname
          (args @ [mkGVar id])
          new_crossed_types (depth + 1) b
      in
      if Id.Set.mem id id_to_exclude && depth >= nb_args then
        (new_b, Id.Set.remove id (Id.Set.filter not_free_in_t id_to_exclude))
      else
        ( DAst.make @@ GProd (n, None, k, t, new_b)
        , Id.Set.filter not_free_in_t id_to_exclude )
    | _ -> anomaly (Pp.str "Should not have an anonymous function here.")
    (* We have renamed all the anonymous functions during alpha_renaming phase *)
    )
  | GLetIn (n, _, v, t, b) -> (
    let t =
      match t with
      | None -> v
      | Some t -> DAst.make ?loc:rt.loc @@ GCast (v, Some DEFAULTcast, t)
    in
    let not_free_in_t id = not (is_free_in id t) in
    let evd = Evd.from_env env in
    let t', ctx = Pretyping.understand env evd t in
    let evd = Evd.from_ctx ctx in
    let type_t' = Retyping.get_type_of env evd t' in
    let new_env =
      EConstr.push_rel (LocalDef (make_annot n ERelevance.relevant, t', type_t')) env
    in
    let new_b, id_to_exclude =
      rebuild_cons new_env nb_args relname args (t :: crossed_types) (depth + 1)
        b
    in
    match n with
    | Name id when Id.Set.mem id id_to_exclude && depth >= nb_args ->
      (new_b, Id.Set.remove id (Id.Set.filter not_free_in_t id_to_exclude))
    | _ ->
      ( DAst.make @@ GLetIn (n, None, t, None, new_b)
      , (* HOPING IT WOULD WORK *)
        Id.Set.filter not_free_in_t id_to_exclude ) )
  | GLetTuple (nal, (na, rto), t, b) ->
    assert (Option.is_empty rto);
    let not_free_in_t id = not (is_free_in id t) in
    let new_t, id_to_exclude' =
      rebuild_cons env nb_args relname args crossed_types depth t
    in
    let t', ctx = Pretyping.understand env (Evd.from_env env) new_t in
    let r = ERelevance.relevant in
    (* TODO relevance *)
    let new_env = EConstr.push_rel (LocalAssum (make_annot na r, t')) env in
    let new_b, id_to_exclude =
      rebuild_cons new_env nb_args relname args (t :: crossed_types) (depth + 1)
        b
    in
    (* 	  match n with  *)
    (* 	    | Name id when Id.Set.mem id id_to_exclude ->  *)
    (* 		new_b,Id.Set.remove id (Id.Set.filter not_free_in_t id_to_exclude) *)
    (* 	    | _ -> *)
    ( DAst.make @@ GLetTuple (nal, (na, None), t, new_b)
    , Id.Set.filter not_free_in_t (Id.Set.union id_to_exclude id_to_exclude') )
  | _ -> (mkGApp (mkGVar relname, args @ [rt]), Id.Set.empty)

(* debugging wrapper *)
let rebuild_cons env nb_args relname args crossed_types rt =
  (*   observennl  (str "rebuild_cons : rt := "++ pr_glob_constr rt ++  *)
  (* 		 str "nb_args := " ++ str (string_of_int nb_args)); *)
  let res = rebuild_cons env nb_args relname args crossed_types 0 rt in
  (*   observe (str " leads to "++ pr_glob_constr (fst res)); *)
  res

(* naive implementation of parameter detection.

   A parameter is an argument which is only preceded by parameters and whose
   calls are all syntactically equal.

   TODO: Find a valid way to deal with implicit arguments here!
*)
let rec compute_cst_params relnames params gt =
  DAst.with_val
    (function
      | GRef _ | GVar _ | GEvar _ | GPatVar _
      | GInt _ | GFloat _ | GString _ -> params
      | GApp (f, args) -> (
        match DAst.get f with
        | GVar relname' when Id.Set.mem relname' relnames ->
          compute_cst_params_from_app [] (params, args)
        | _ -> List.fold_left (compute_cst_params relnames) params (f :: args) )
      | GProj (f, args, c) ->
        List.fold_left (compute_cst_params relnames) params (args @ [c])
      | GLambda (_, _, _, t, b) | GProd (_, _, _, t, b) | GLetTuple (_, _, t, b) ->
        let t_params = compute_cst_params relnames params t in
        compute_cst_params relnames t_params b
      | GLetIn (_, _, v, t, b) ->
        let v_params = compute_cst_params relnames params v in
        let t_params =
          Option.fold_left (compute_cst_params relnames) v_params t
        in
        compute_cst_params relnames t_params b
      | GCases _ ->
        params
        (* If there is still cases at this point they can only be
           discrimination ones *)
      | GSort _ -> params
      | GHole _ -> params
      | GGenarg _ -> params
      | GIf _ | GRec _ | GCast _ | GArray _ ->
        CErrors.user_err (str "Unhandled case."))
    gt

and compute_cst_params_from_app acc (params, rtl) =
  let is_gid id c =
    match DAst.get c with GVar id' -> Id.equal id id' | _ -> false
  in
  match (params, rtl) with
  | _ :: _, [] -> assert false (* the rel has at least nargs + 1 arguments ! *)
  | ((Name id, _, None) as param) :: params', c :: rtl' when is_gid id c ->
    compute_cst_params_from_app (param :: acc) (params', rtl')
  | _ -> List.rev acc

let compute_params_name relnames
    (args : (Name.t * Glob_term.glob_constr * glob_constr option) list array)
    csts =
  let rels_params =
    Array.mapi
      (fun i args ->
        List.fold_left
          (fun params (_, cst) -> compute_cst_params relnames params cst)
          args csts.(i))
      args
  in
  let l = ref [] in
  let _ =
    try
      List.iteri
        (fun i ((n, nt, typ) as param) ->
          if
            Array.for_all
              (fun l ->
                let n', nt', typ' = List.nth l i in
                Name.equal n n' && glob_constr_eq nt nt'
                && Option.equal glob_constr_eq typ typ')
              rels_params
          then l := param :: !l)
        rels_params.(0)
    with e when CErrors.noncritical e -> ()
  in
  List.rev !l

let rec rebuild_return_type rt =
  let loc = rt.CAst.loc in
  match rt.CAst.v with
  | Constrexpr.CProdN (n, t') ->
    CAst.make ?loc @@ Constrexpr.CProdN (n, rebuild_return_type t')
  | Constrexpr.CLetIn (na, v, t, t') ->
    CAst.make ?loc @@ Constrexpr.CLetIn (na, v, t, rebuild_return_type t')
  | _ ->
    CAst.make ?loc
    @@ Constrexpr.CProdN
         ( [ Constrexpr.CLocalAssum
               ([CAst.make Anonymous], None, Constrexpr.Default Explicit, rt) ]
         , CAst.make @@ Constrexpr.CSort Constrexpr_ops.expr_Type_sort )

let do_build_inductive evd (funconstants : pconstant list)
    (funsargs : (Name.t * glob_constr * glob_constr option) list list)
    returned_types (rtl : glob_constr list) =
  let funnames =
    List.map
      (fun c -> Label.to_id (KerName.label (Constant.canonical (fst c))))
      funconstants
  in
  (*   Pp.msgnl (prlist_with_sep fnl Printer.pr_glob_constr rtl); *)
  let funnames_as_set = List.fold_right Id.Set.add funnames Id.Set.empty in
  let funnames = Array.of_list funnames in
  let funsargs = Array.of_list funsargs in
  let returned_types = Array.of_list returned_types in
  (* alpha_renaming of the body to prevent variable capture during manipulation *)
  let rtl_alpha = List.map (function rt -> expand_as (alpha_rt [] rt)) rtl in
  let rta = Array.of_list rtl_alpha in
  (*i The next call to mk_rel_id is valid since we are constructing the graph
    Ensures by: obvious
    i*)
  let relnames = Array.map mk_rel_id funnames in
  let relnames_as_set = Array.fold_right Id.Set.add relnames Id.Set.empty in
  (* Construction of the pseudo constructors *)
  let open Context.Named.Declaration in
  let evd, env =
    Array.fold_right2
      (fun id (c, u) (evd, env) ->
        let u = EConstr.EInstance.make u in
        let evd, t = Typing.type_of env evd (EConstr.mkConstU (c, u)) in
        ( evd
        , EConstr.push_named (LocalAssum (make_annot id ERelevance.relevant, t)) env
        ))
      funnames
      (Array.of_list funconstants)
      (evd, Global.env ())
  in
  (* we solve and replace the implicits *)
  let rta =
    Array.mapi
      (fun i rt ->
        let _, t =
          Typing.type_of env evd
            (EConstr.of_constr (mkConstU (Array.of_list funconstants).(i)))
        in
        resolve_and_replace_implicits t env
          evd rt)
      rta
  in
  let resa = Array.map (build_entry_lc env evd funnames_as_set []) rta in
  let env_with_graphs =
    let rel_arity i funargs =
      (* Rebuilding arities (with parameters) *)
      let rel_first_args :
          (Name.t * Glob_term.glob_constr * Glob_term.glob_constr option) list =
        funargs
      in
      List.fold_right
        (fun (n, t, typ) acc ->
          match typ with
          | Some typ ->
            CAst.make
            @@ Constrexpr.CLetIn
                 ( CAst.make n
                 , with_full_print
                     Constrextern.(extern_glob_constr empty_extern_env)
                     t
                 , Some
                     (with_full_print
                        Constrextern.(extern_glob_constr empty_extern_env)
                        typ)
                 , acc )
          | None ->
            CAst.make
            @@ Constrexpr.CProdN
                 ( [ Constrexpr.CLocalAssum
                       ( [CAst.make n]
                       , None
                       , Constrexpr_ops.default_binder_kind
                       , with_full_print
                           Constrextern.(extern_glob_constr empty_extern_env)
                           t ) ]
                 , acc ))
        rel_first_args
        (rebuild_return_type returned_types.(i))
    in
    (* We need to lift back our work topconstr but only with all information
       We mimic a Set Printing All.
       Then save the graphs and reset Printing options to their primitive values
    *)
    let rel_arities = Array.mapi rel_arity funsargs in
    Util.Array.fold_left2
      (fun env rel_name rel_ar ->
        let rex =
          fst (with_full_print (Constrintern.interp_constr env evd) rel_ar)
        in
        let r = ERelevance.relevant in
        (* TODO relevance *)
        EConstr.push_named (LocalAssum (make_annot rel_name r, rex)) env)
      env relnames rel_arities
  in
  (* and of the real constructors*)
  let constr i res =
    List.map
      (function
        | result (* (args',concl') *) ->
          let rt = compose_glob_context result.context result.value in
          let nb_args = List.length funsargs.(i) in
          (*  with_full_print (fun rt -> Pp.msgnl (str "glob constr " ++ pr_glob_constr rt)) rt; *)
          fst (rebuild_cons env_with_graphs nb_args relnames.(i) [] [] rt))
      res.result
  in
  (* adding names to constructors  *)
  let next_constructor_id = ref (-1) in
  let mk_constructor_id i =
    incr next_constructor_id;
    (*i The next call to mk_rel_id is valid since we are constructing the graph
      Ensures by: obvious
      i*)
    Id.of_string
      ( Id.to_string (mk_rel_id funnames.(i))
      ^ "_"
      ^ string_of_int !next_constructor_id )
  in
  let rel_constructors i rt : (Id.t * glob_constr) list =
    next_constructor_id := -1;
    List.map (fun constr -> (mk_constructor_id i, constr)) (constr i rt)
  in
  let rel_constructors = Array.mapi rel_constructors resa in
  (* Computing the set of parameters if asked *)
  let rels_params =
    compute_params_name relnames_as_set funsargs rel_constructors
  in
  let nrel_params = List.length rels_params in
  let rel_constructors =
    (* Taking into account the parameters in constructors *)
    Array.map
      (List.map (fun (id, rt) -> (id, snd (chop_rprod_n nrel_params rt))))
      rel_constructors
  in
  let rel_arity i funargs =
    (* Reduilding arities (with parameters) *)
    let rel_first_args :
        (Name.t * Glob_term.glob_constr * Glob_term.glob_constr option) list =
      snd (List.chop nrel_params funargs)
    in
    List.fold_right
      (fun (n, t, typ) acc ->
        match typ with
        | Some typ ->
          CAst.make
          @@ Constrexpr.CLetIn
               ( CAst.make n
               , with_full_print
                   Constrextern.(extern_glob_constr empty_extern_env)
                   t
               , Some
                   (with_full_print
                      Constrextern.(extern_glob_constr empty_extern_env)
                      typ)
               , acc )
        | None ->
          CAst.make
          @@ Constrexpr.CProdN
               ( [ Constrexpr.CLocalAssum
                     ( [CAst.make n]
                     , None
                     , Constrexpr_ops.default_binder_kind
                     , with_full_print
                         Constrextern.(extern_glob_constr empty_extern_env)
                         t ) ]
               , acc ))
      rel_first_args
      (rebuild_return_type returned_types.(i))
  in
  (* We need to lift back our work topconstr but only with all information
     We mimic a Set Printing All.
     Then save the graphs and reset Printing options to their primitive values
  *)
  let rel_arities = Array.mapi rel_arity funsargs in
  let rel_params_ids =
    List.fold_left
      (fun acc (na, _, _) ->
        match na with Anonymous -> acc | Name id -> id :: acc)
      [] rels_params
  in
  let rel_params =
    List.map
      (fun (n, t, typ) ->
        match typ with
        | Some typ ->
          Constrexpr.CLocalDef
            ( CAst.make n
            , None
            , Constrextern.(extern_glob_constr empty_extern_env) t
            , Some
                (with_full_print
                   Constrextern.(extern_glob_constr empty_extern_env)
                   typ) )
        | None ->
          Constrexpr.CLocalAssum
            ( [CAst.make n]
            , None
            , Constrexpr_ops.default_binder_kind
            , Constrextern.(extern_glob_constr empty_extern_env) t ))
      rels_params
  in
  let ext_rels_constructors =
    Array.map
      (List.map (fun (id, t) ->
           ( Vernacexpr.([], NoCoercion, NoInstance)
           , ( CAst.make id
             , with_full_print
                 Constrextern.(extern_glob_type empty_extern_env)
                 ((* zeta_normalize *) alpha_rt rel_params_ids t) ) )))
      rel_constructors
  in
  let rel_ind i ext_rel_constructors =
    ( ( CAst.make @@ relnames.(i)
      , (rel_params, None)
      , Some rel_arities.(i)
      , ext_rel_constructors )
    , [] )
  in
  let ext_rel_constructors = Array.mapi rel_ind ext_rels_constructors in
  let rel_inds = Array.to_list ext_rel_constructors in
  (*   let _ =  *)
  (*   Pp.msgnl  (\* observe *\) ( *)
  (*       str "Inductive" ++ spc () ++ *)
  (* 	prlist_with_sep  *)
  (* 	(fun () -> fnl ()++spc () ++ str "with" ++ spc ())  *)
  (* 	(function ((_,id),_,params,ar,constr) ->  *)
  (* 	   Ppconstr.pr_id id ++ spc () ++  *)
  (* 	     Ppconstr.pr_binders params ++ spc () ++ *)
  (* 	     str ":" ++ spc () ++  *)
  (* 	     Ppconstr.pr_lconstr_expr ar ++ spc () ++ str ":=" ++ *)
  (* 	     prlist_with_sep  *)
  (* 	     (fun _ -> fnl () ++ spc () ++ str "|" ++ spc ()) *)
  (* 	     (function (_,((_,id),t)) ->  *)
  (* 		Ppconstr.pr_id id ++ spc () ++ str ":" ++ spc () ++ *)
  (* 		  Ppconstr.pr_lconstr_expr t) *)
  (* 	     constr *)
  (* 	) *)
  (* 	rel_inds *)
  (*     ) *)
  (*   in *)
  try
    let flags = {
      ComInductive.poly = false;
      cumulative = false;
      template = Some false;
      auto_prop_lowering = false;
      finite = Finite;
      mode = None;
    }
    in
    with_full_print
      (Flags.silently
         (fun () ->
            ComInductive.do_mutual_inductive ~flags
              None rel_inds
              ~private_ind:false
              ~uniform:ComInductive.NonUniformParameters))
      ()
  with
  | UserError msg as e ->
    let repacked_rel_inds =
      List.map
        (fun ((a, b, c, l), ntn) ->
          (Vernacexpr.((NoCoercion, (a, None)), b, c, Constructors l), ntn))
        rel_inds
    in
    let msg =
      str "while trying to define"
      ++ spc ()
      ++ Ppvernac.pr_vernac
           (CAst.make
              Vernacexpr.
                { control = []
                ; attrs = []
                ; expr =
                    VernacSynPure (VernacInductive (Vernacexpr.Inductive_kw, repacked_rel_inds))
                })
      ++ fnl () ++ msg
    in
    observe msg; raise e
  | reraise ->
    let repacked_rel_inds =
      List.map
        (fun ((a, b, c, l), ntn) ->
          (Vernacexpr.((NoCoercion, (a, None)), b, c, Constructors l), ntn))
        rel_inds
    in
    let msg =
      str "while trying to define"
      ++ spc ()
      ++ Ppvernac.pr_vernac
           ( CAst.make
           @@ Vernacexpr.
                { control = []
                ; attrs = []
                ; expr =
                    VernacSynPure (VernacInductive (Vernacexpr.Inductive_kw, repacked_rel_inds))
                } )
      ++ fnl () ++ CErrors.print reraise
    in
    observe msg; raise reraise

let build_inductive evd funconstants funsargs returned_types rtl =
  let pu = !Detyping.print_universes in
  let cu = !Constrextern.print_universes in
  try
    Detyping.print_universes := true;
    Constrextern.print_universes := true;
    do_build_inductive evd funconstants funsargs returned_types rtl;
    Detyping.print_universes := pu;
    Constrextern.print_universes := cu
  with e when CErrors.noncritical e ->
    Detyping.print_universes := pu;
    Constrextern.print_universes := cu;
    raise (Building_graph e)
