(*
 * Copyright (c) 2017 - present Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *)

open! IStd

(** To be used in 'list_constraint *)
type accept_more
 and end_of_list

(** To be used in 'emptyness *)
type empty
 and non_empty

(* Type shorthands *)

type typ = Typ.t

type c = Typ.Procname.c

type objc_cpp = Typ.Procname.ObjC_Cpp.t

type qual_name = QualifiedCppName.t

type templated_name = qual_name * Typ.template_arg list

type 'marker mtyp = typ

type 'captured_types capt = unit -> 'captured_types

(* Typ helpers *)

let template_args_of_template_spec_info = function
  | Typ.NoTemplate ->
      []
  | Typ.Template {args} ->
      args


exception DoNotHandleJavaYet

let templated_name_of_class_name class_name =
  let open Typ in
  match class_name with
  | CStruct qual_name | CUnion qual_name | ObjcClass qual_name | ObjcProtocol qual_name ->
      (qual_name, [])
  | CppClass (qual_name, template_spec_info) ->
      (qual_name, template_args_of_template_spec_info template_spec_info)
  | JavaClass _ ->
      raise DoNotHandleJavaYet


(* Intermediate matcher types *)

type ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out) name_matcher =
  { on_objc_cpp: 'f_in -> objc_cpp -> ('f_out * 'captured_types capt) option
  ; on_qual_name: 'f_in -> qual_name -> ('f_out * 'captured_types capt) option
  ; get_markers: 'markers_in -> 'markers_out }

type ( 'f_in
     , 'f_out
     , 'captured_types_in
     , 'captured_types_out
     , 'markers_in
     , 'markers_out
     , 'list_constraint ) template_arg =
  { eat_template_arg:
      'f_in * 'captured_types_in capt * Typ.template_arg list
      -> ('f_out * 'captured_types_out capt * Typ.template_arg list) option
  ; add_marker: 'markers_in -> 'markers_out }

type ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out, 'list_constraint) templ_matcher =
  { on_objc_cpp: 'f_in -> objc_cpp -> ('f_out * 'captured_types capt * Typ.template_arg list) option
  ; on_templated_name:
      'f_in -> templated_name -> ('f_out * 'captured_types capt * Typ.template_arg list) option
  ; get_markers: 'markers_in -> 'markers_out }

type ('f_in, 'f_out, 'captured_types, 'emptyness) path_extra =
  | PathEmpty : ('f, 'f, unit, empty) path_extra
  | PathNonEmpty:
      { on_objc_cpp: 'f_in -> objc_cpp -> ('f_out * 'captured_types capt) option }
      -> ('f_in, 'f_out, 'captured_types, non_empty) path_extra

type ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out, 'emptyness) path_matcher =
  { on_templated_name: 'f_in -> templated_name -> ('f_out * 'captured_types capt) option
  ; path_extra: ('f_in, 'f_out, 'captured_types, 'emptyness) path_extra
  ; get_markers: 'markers_in -> 'markers_out }

(* Combinators *)

let empty : ('f, 'f, unit, 'markers, 'markers, empty) path_matcher =
  let get_markers m = m in
  let get_capture () = () in
  let on_templated_name f (qual_name, template_args) =
    match (QualifiedCppName.extract_last qual_name, template_args) with
    | None, [] ->
        Some (f, get_capture)
    | None, _ ->
        assert false
    | Some _, _ ->
        None
  in
  {on_templated_name; path_extra= PathEmpty; get_markers}


let name_cons
    : ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out, _) path_matcher -> string
      -> ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out) name_matcher =
 fun m name ->
  let {on_templated_name; get_markers} = m in
  let fuzzy_name_regexp =
    name |> Str.quote |> Printf.sprintf "^%s\\(<[a-z0-9]+>\\)?$" |> Str.regexp
  in
  let on_qual_name f qual_name =
    match QualifiedCppName.extract_last qual_name with
    | Some (last, rest) when Str.string_match fuzzy_name_regexp last 0 ->
        on_templated_name f (rest, [])
    | _ ->
        None
  in
  let on_objc_cpp f (objc_cpp: Typ.Procname.ObjC_Cpp.t) =
    if String.equal name objc_cpp.method_name then
      on_templated_name f (templated_name_of_class_name objc_cpp.class_name)
    else None
  in
  {on_objc_cpp; on_qual_name; get_markers}


let all_names_cons
    : ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out, non_empty) path_matcher
      -> ('f_in, 'f_out, 'captured_tpes, 'markers_in, 'markers_out, non_empty) path_matcher =
 fun m ->
  let {on_templated_name; get_markers; path_extra= PathNonEmpty {on_objc_cpp}} = m in
  let rec on_templated_name_rec f templated_name =
    match on_templated_name f templated_name with
    | Some _ as some ->
        some
    | None ->
        let qual_name, _template_args = templated_name in
        match QualifiedCppName.extract_last qual_name with
        | None ->
            None
        | Some (_last, rest) ->
            on_templated_name_rec f (rest, [])
  in
  let on_templated_name = on_templated_name_rec in
  let on_objc_cpp f (objc_cpp: Typ.Procname.ObjC_Cpp.t) =
    match on_objc_cpp f objc_cpp with
    | Some _ as some ->
        some
    | None ->
        on_templated_name f (templated_name_of_class_name objc_cpp.class_name)
  in
  {on_templated_name; get_markers; path_extra= PathNonEmpty {on_objc_cpp}}


let templ_begin
    : ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out) name_matcher
      -> ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out, accept_more) templ_matcher =
 fun m ->
  let {on_objc_cpp; on_qual_name; get_markers} = m in
  let on_templated_name f (qual_name, template_args) =
    match on_qual_name f qual_name with
    | None ->
        None
    | Some (f, captured_types) ->
        Some (f, captured_types, template_args)
  in
  let on_objc_cpp f (objc_cpp: Typ.Procname.ObjC_Cpp.t) =
    match on_objc_cpp f objc_cpp with
    | None ->
        None
    | Some (f, captured_types) ->
        let template_args = template_args_of_template_spec_info objc_cpp.template_args in
        Some (f, captured_types, template_args)
  in
  {on_objc_cpp; on_templated_name; get_markers}


let templ_cons
    : ( 'f_in
      , 'f_interm
      , 'captured_types_in
      , 'markers_interm
      , 'markers_out
      , accept_more )
      templ_matcher
      -> ( 'f_interm
         , 'f_out
         , 'captured_types_in
         , 'captured_types_out
         , 'markers_in
         , 'markers_interm
         , 'lc )
         template_arg
      -> ('f_in, 'f_out, 'captured_types_out, 'markers_in, 'markers_out, 'lc) templ_matcher =
 fun m template_arg ->
  let {on_objc_cpp; on_templated_name; get_markers} = m in
  let {eat_template_arg; add_marker} = template_arg in
  let get_markers m = get_markers (add_marker m) in
  let on_templated_name f templated_name =
    on_templated_name f templated_name |> Option.bind ~f:eat_template_arg
  in
  let on_objc_cpp f objc_cpp = on_objc_cpp f objc_cpp |> Option.bind ~f:eat_template_arg in
  {on_objc_cpp; on_templated_name; get_markers}


let templ_end
    : ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out, _) templ_matcher
      -> ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out, non_empty) path_matcher =
  let match_empty_templ_args (f, captured_types, template_args) =
    match template_args with [] -> Some (f, captured_types) | _ -> None
  in
  fun m ->
    let {on_objc_cpp; on_templated_name; get_markers} = m in
    let on_templated_name f templated_name =
      on_templated_name f templated_name |> Option.bind ~f:match_empty_templ_args
    in
    let on_objc_cpp f objc_cpp = on_objc_cpp f objc_cpp |> Option.bind ~f:match_empty_templ_args in
    {on_templated_name; path_extra= PathNonEmpty {on_objc_cpp}; get_markers}


module type Common = sig
  type 'f matcher

  type 'f dispatcher

  val make_dispatcher : 'f matcher list -> 'f dispatcher

  (* Template arguments *)

  val any_typ :
    ('f, 'f, 'captured_types, 'captured_types, 'markers, 'markers, accept_more) template_arg
  (** Eats a type *)

  val capt_typ :
    'marker
    -> ( 'marker mtyp -> 'f
       , 'f
       , 'captured_types
       , 'marker mtyp * 'captured_types
       , 'markers
       , 'marker * 'markers
       , accept_more )
       template_arg
  (** Captures a type than can be back-referenced *)

  val capt_int :
    ( Int64.t -> 'f
    , 'f
    , 'captured_types
    , 'captured_types
    , 'markers
    , 'markers
    , accept_more )
    template_arg
  (** Captures an int *)

  val capt_all :
    ( Typ.template_arg list -> 'f
    , 'f
    , 'captured_types
    , 'captured_types
    , 'markers
    , 'markers
    , end_of_list )
    template_arg
  (** Captures all template args *)

  val ( ~- ) : string -> ('f, 'f, unit, 'markers, 'markers) name_matcher
  (** Starts a path with a name *)

  val ( &+ ) :
    ( 'f_in
    , 'f_interm
    , 'captured_types_in
    , 'markers_interm
    , 'markers_out
    , accept_more )
    templ_matcher
    -> ( 'f_interm
       , 'f_out
       , 'captured_types_in
       , 'captured_types_out
       , 'markers_in
       , 'markers_interm
       , 'lc )
       template_arg
    -> ('f_in, 'f_out, 'captured_types_out, 'markers_in, 'markers_out, 'lc) templ_matcher
  (** Separate template arguments *)

  val ( < ) :
    ('f_in, 'f_interm, 'captured_types_in, 'markers_interm, 'markers_out) name_matcher
    -> ( 'f_interm
       , 'f_out
       , 'captured_types_in
       , 'captured_types_out
       , 'markers_in
       , 'markers_interm
       , 'lc )
       template_arg
    -> ('f_in, 'f_out, 'captured_types_out, 'markers_in, 'markers_out, 'lc) templ_matcher
  (** Starts template arguments after a name *)

  val ( >:: ) :
    ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out, _) templ_matcher -> string
    -> ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out) name_matcher
  (** Ends template arguments and starts a name *)

  val ( &+...>:: ) :
    ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out, accept_more) templ_matcher
    -> string -> ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out) name_matcher
  (** Ends template arguments with eats-ALL and starts a name *)

  val ( &:: ) :
    ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out) name_matcher -> string
    -> ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out) name_matcher
  (** Separates names (accepts ALL template arguments on the left one) *)

  val ( <>:: ) :
    ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out) name_matcher -> string
    -> ('f_in, 'f_out, 'captured_types, 'markers_in, 'markers_out) name_matcher
  (** Separates names (accepts NO template arguments on the left one) *)
end

module Common = struct
  (* Template arguments *)

  let add_no_marker capture_markers = capture_markers

  (** Eats all template args *)
  let any_template_args
      : ('f, 'f, 'captured_types, 'captured_types, 'markers, 'markers, end_of_list) template_arg =
    let eat_template_arg (f, captured_types, _) = Some (f, captured_types, []) in
    {eat_template_arg; add_marker= add_no_marker}


  (** Eats a type *)
  let any_typ
      : ('f, 'f, 'captured_types, 'captured_types, 'markers, 'markers, accept_more) template_arg =
    let eat_template_arg (f, captured_types, template_args) =
      match template_args with
      | (Typ.TType _) :: rest ->
          Some (f, captured_types, rest)
      | _ ->
          None
    in
    {eat_template_arg; add_marker= add_no_marker}


  (** Captures a type than can be back-referenced *)
  let capt_typ
      : 'marker
        -> ( 'marker mtyp -> 'f
           , 'f
           , 'captured_types
           , 'marker mtyp * 'captured_types
           , 'markers
           , 'marker * 'markers
           , accept_more )
           template_arg =
   fun marker ->
    let eat_template_arg (f, captured_types, template_args) =
      match template_args with
      | (Typ.TType ty) :: rest ->
          let captured_types () = (ty, captured_types ()) in
          Some (f ty, captured_types, rest)
      | _ ->
          None
    in
    let add_marker capture_markers = (marker, capture_markers) in
    {eat_template_arg; add_marker}


  (** Captures an int *)
  let capt_int
      : ( Int64.t -> 'f
        , 'f
        , 'captured_types
        , 'captured_types
        , 'markers
        , 'markers
        , accept_more )
        template_arg =
    let eat_template_arg (f, captured_types, template_args) =
      match template_args with
      | (Typ.TInt i) :: rest ->
          Some (f i, captured_types, rest)
      | _ ->
          None
    in
    {eat_template_arg; add_marker= add_no_marker}


  (** Captures all template args *)
  let capt_all
      : ( Typ.template_arg list -> 'f
        , 'f
        , 'captured_types
        , 'captured_types
        , 'markers
        , 'markers
        , end_of_list )
        template_arg =
    let eat_template_arg (f, captured_types, template_args) =
      Some (f template_args, captured_types, [])
    in
    {eat_template_arg; add_marker= add_no_marker}


  let ( <! ) name_matcher () = templ_begin name_matcher

  let ( >! ) templ_matcher () = templ_end templ_matcher

  let ( &::! ) path_matcher name = name_cons path_matcher name

  let ( &::.*! ) path_matcher () = all_names_cons path_matcher

  let ( ~- ) name = empty &::! name

  let ( &+ ) templ_matcher template_arg = templ_cons templ_matcher template_arg

  let ( &+...>! ) templ_matcher () = templ_matcher &+ any_template_args >! ()

  let ( <...>! ) name_matcher () = name_matcher <! () &+...>! ()

  let ( < ) name_matcher template_arg = name_matcher <! () &+ template_arg

  let ( >:: ) templ_matcher name = templ_matcher >! () &::! name

  let ( &+...>:: ) templ_matcher name = templ_matcher &+...>! () &::! name

  let ( &:: ) name_matcher name = name_matcher <...>! () &::! name

  let ( <>:: ) name_matcher name = name_matcher <! () >:: name
end

module Call = struct
  include Common

  (** Little abstraction over arguments: currently actual args, we'll want formal args later *)
  module FuncArg = struct
    type t = Exp.t * Typ.t

    let typ (_, ty) = ty

    let exp (e, _) = e
  end

  type ('f_in, 'f_out, 'captured_types) proc_matcher =
    { on_objc_cpp: 'f_in -> objc_cpp -> ('f_out * 'captured_types) option
    ; on_c: 'f_in -> c -> ('f_out * 'captured_types) option }

  type ('f_in, 'f_out, 'captured_types) on_args =
    'captured_types -> 'f_in * FuncArg.t list -> ('f_out * FuncArg.t list) option

  type ('f_in, 'f_proc_out, 'f_out, 'captured_types, 'markers) args_matcher =
    { on_proc: ('f_in, 'f_proc_out, 'captured_types) proc_matcher
    ; on_args: ('f_proc_out, 'f_out, 'captured_types) on_args
    ; markers: 'markers }

  type ('captured_types, 'markers) one_arg_matcher =
    {match_arg: 'captured_types -> FuncArg.t -> bool; marker_static_checker: 'markers -> bool}

  type ('arg_in, 'arg_out, 'f_in, 'f_out) arg_capture =
    {get_captured_value: FuncArg.t -> 'arg_in; do_capture: 'f_in -> 'arg_out -> 'f_out}

  type ('arg_in, 'arg_out, 'f_in, 'f_out, 'captured_types, 'markers) one_arg =
    { one_arg_matcher: ('captured_types, 'markers) one_arg_matcher
    ; capture: ('arg_in, 'arg_out, 'f_in, 'f_out) arg_capture }

  type ('arg_in, 'arg_out, 'f_in, 'f_out) arg_preparer =
    { on_empty: ('f_in -> 'arg_out -> 'f_out) -> 'f_in -> ('f_out * FuncArg.t list) option
    ; wrapper: 'arg_in -> 'arg_out }

  type ('f_in, 'f_out, 'captured_types, 'markers) func_arg =
    { eat_func_arg: ('f_in, 'f_out, 'captured_types) on_args
    ; marker_static_checker: 'markers -> bool }

  type 'f matcher =
    {on_objc_cpp: objc_cpp -> FuncArg.t list -> 'f option; on_c: c -> FuncArg.t list -> 'f option}

  type 'f pre_result = DoesNotMatch | Matches of 'f | RetryWith of 'f matcher

  let pre_bind_opt opt ~f = match opt with None -> DoesNotMatch | Some x -> f x

  let pre_map_opt opt ~f = match opt with None -> DoesNotMatch | Some x -> Matches (f x)

  type ('f_in, 'f_out, 'captured_types) func_args_end =
    on_args:('f_in, 'f_out, 'captured_types) on_args -> FuncArg.t list -> 'f_in * 'captured_types
    -> 'f_out pre_result

  type ('f_in, 'f_out) all_args_matcher =
    { on_objc_cpp: 'f_in -> objc_cpp -> FuncArg.t list -> 'f_out pre_result
    ; on_c: 'f_in -> c -> FuncArg.t list -> 'f_out pre_result }

  type 'f dispatcher = Typ.Procname.t -> FuncArg.t list -> 'f option

  let args_begin
      : ('f_in, 'f_out, 'captured_types, unit, 'markers, non_empty) path_matcher
        -> ('f_in, 'f_out, 'f_out, 'captured_types, 'markers) args_matcher =
    let on_args _capt f_args = Some f_args in
    fun m ->
      let {on_templated_name; path_extra= PathNonEmpty {on_objc_cpp}; get_markers} = m in
      let markers = get_markers () in
      let get_captures (f, captured_types) = (f, captured_types ()) in
      let on_c f (c: c) =
        let template_args = template_args_of_template_spec_info c.template_args in
        on_templated_name f (c.name, template_args) |> Option.map ~f:get_captures
      in
      let on_objc_cpp f objc_cpp = on_objc_cpp f objc_cpp |> Option.map ~f:get_captures in
      let on_proc : (_, _, _) proc_matcher = {on_objc_cpp; on_c} in
      {on_proc; on_args; markers}


  let args_cons
      : ('f_in, 'f_proc_out, 'f_interm, 'captured_types, 'markers) args_matcher
        -> ('f_interm, 'f_out, 'captured_types, 'markers) func_arg
        -> ('f_in, 'f_proc_out, 'f_out, 'captured_types, 'markers) args_matcher =
   fun m func_arg ->
    let {on_proc; on_args; markers} = m in
    let {marker_static_checker; eat_func_arg} = func_arg in
    assert (marker_static_checker markers) ;
    let on_args capt f_args = on_args capt f_args |> Option.bind ~f:(eat_func_arg capt) in
    {on_proc; on_args; markers}


  let args_end
      : ('f_in, 'f_proc_out, 'f_out, 'captured_types, 'markers) args_matcher
        -> ('f_proc_out, 'f_out, 'captured_types) func_args_end -> ('f_in, 'f_out) all_args_matcher =
   fun m func_args_end ->
    let {on_proc= {on_c; on_objc_cpp}; on_args} = m in
    let on_c f c args = on_c f c |> pre_bind_opt ~f:(func_args_end ~on_args args) in
    let on_objc_cpp f objc_cpp args =
      on_objc_cpp f objc_cpp |> pre_bind_opt ~f:(func_args_end ~on_args args)
    in
    {on_c; on_objc_cpp}


  let make_matcher : ('f_in, 'f_out) all_args_matcher -> 'f_in -> 'f_out matcher =
   fun m f ->
    let {on_c; on_objc_cpp} : (_, _) all_args_matcher = m in
    let on_objc_cpp objc_cpp args =
      match on_objc_cpp f objc_cpp args with
      | DoesNotMatch ->
          None
      | Matches res ->
          Some res
      | RetryWith {on_objc_cpp} ->
          on_objc_cpp objc_cpp args
    in
    let on_c c args =
      match on_c f c args with
      | DoesNotMatch ->
          None
      | Matches res ->
          Some res
      | RetryWith {on_c} ->
          on_c c args
    in
    {on_objc_cpp; on_c}


  (** Simple implementation of a dispatcher, could be optimized later *)
  let make_dispatcher : 'f matcher list -> 'f dispatcher =
   fun matchers ->
    let on_objc_cpp objc_cpp args =
      List.find_map matchers ~f:(fun (matcher: _ matcher) -> matcher.on_objc_cpp objc_cpp args)
    in
    let on_c c args =
      List.find_map matchers ~f:(fun (matcher: _ matcher) -> matcher.on_c c args)
    in
    fun procname args ->
      match procname with
      | ObjC_Cpp objc_cpp ->
          on_objc_cpp objc_cpp args
      | C c ->
          on_c c args
      | _ ->
          None


  (* Function args *)

  let no_marker_checker _markers = true

  (** Matches any arg *)
  let match_any_arg : (_, _) one_arg_matcher =
    let match_arg _capt _arg = true in
    {match_arg; marker_static_checker= no_marker_checker}


  let mk_match_typ_nth
      : ('markers -> 'marker) -> ('captured_types -> 'marker mtyp) -> 'marker
        -> ('captured_types, 'markers) one_arg_matcher =
   fun get_m get_c marker ->
    let marker_static_checker markers = Polymorphic_compare.( = ) marker (get_m markers) in
    let match_arg capt arg = Typ.equal (FuncArg.typ arg) (get_c capt) in
    {match_arg; marker_static_checker}


  (** Matches first captured type *)
  let match_typ1 : 'marker -> ('marker mtyp * _, 'marker * _) one_arg_matcher =
    let pos1 (x, _) = x in
    fun marker -> mk_match_typ_nth pos1 pos1 marker


  (** Matches second captured type *)
  let match_typ2 : 'marker -> (_ * ('marker mtyp * _), _ * ('marker * _)) one_arg_matcher =
    let pos2 (_, (x, _)) = x in
    fun marker -> mk_match_typ_nth pos2 pos2 marker


  (** Matches third captured type *)
  let match_typ3
      : 'marker -> (_ * (_ * ('marker mtyp * _)), _ * (_ * ('marker * _))) one_arg_matcher =
    let pos3 (_, (_, (x, _))) = x in
    fun marker -> mk_match_typ_nth pos3 pos3 marker


  (** Matches the type matched by the given path_matcher *)
  let match_typ : (_, _, unit, unit, unit, non_empty) path_matcher -> (_, _) one_arg_matcher =
   fun m ->
    let {on_templated_name} : (_, _, unit, unit, unit, non_empty) path_matcher = m in
    let rec match_typ typ =
      match typ with
      | {Typ.desc= Tstruct name} ->
          name |> templated_name_of_class_name |> on_templated_name () |> Option.is_some
      | {Typ.desc= Tptr (typ, _ptr_kind)} ->
          match_typ typ
      | _ ->
          false
    in
    let match_arg _capt arg = match_typ (FuncArg.typ arg) in
    {match_arg; marker_static_checker= no_marker_checker}


  (* Function argument capture *)
  (** Do not capture this argument *)
  let no_capture : (_, _, 'f, 'f) arg_capture =
    let get_captured_value _arg = () in
    let do_capture f _v = f in
    {get_captured_value; do_capture}


  (** Capture the argument *)
  let capture_arg : (FuncArg.t, 'wrapped_arg, 'wrapped_arg -> 'f, 'f) arg_capture =
    let get_captured_value arg = arg in
    let do_capture f v = f v in
    {get_captured_value; do_capture}


  (** Capture the argument expression *)
  let capture_arg_exp : (Exp.t, 'wrapped_arg, 'wrapped_arg -> 'f, 'f) arg_capture =
    let get_captured_value arg = FuncArg.exp arg in
    let do_capture f v = f v in
    {get_captured_value; do_capture}


  let mandatory_arg =
    let on_empty _do_capture _f = None in
    let wrapper = Fn.id in
    {on_empty; wrapper}


  let optional_arg =
    let on_empty do_capture f = Some (do_capture f None, []) in
    let wrapper = Option.some in
    {on_empty; wrapper}


  let make_arg
      : ('arg_in, 'arg_out, 'f_in, 'f_out) arg_preparer
        -> ('arg_in, 'arg_out, 'f_in, 'f_out, _, _) one_arg -> ('f_in, 'f_out, _, _) func_arg =
   fun arg_preparer one_arg ->
    let {on_empty; wrapper} = arg_preparer in
    let {one_arg_matcher; capture} = one_arg in
    let {match_arg; marker_static_checker} = one_arg_matcher in
    let {get_captured_value; do_capture} = capture in
    let eat_func_arg capt (f, args) =
      match args with
      | [] ->
          on_empty do_capture f
      | arg :: rest when match_arg capt arg ->
          Some (arg |> get_captured_value |> wrapper |> do_capture f, rest)
      | _ ->
          None
    in
    {eat_func_arg; marker_static_checker}


  let any_arg : (unit, _, 'f, 'f, _, _) one_arg =
    {one_arg_matcher= match_any_arg; capture= no_capture}


  let capt_arg : (FuncArg.t, 'wrapped_arg, 'wrapped_arg -> 'f, 'f, _, _) one_arg =
    {one_arg_matcher= match_any_arg; capture= capture_arg}


  let capt_exp : (Exp.t, 'wrapped_arg, 'wrapped_arg -> 'f, 'f, _, _) one_arg =
    {one_arg_matcher= match_any_arg; capture= capture_arg_exp}


  let capt_arg_of_typ m = {one_arg_matcher= match_typ (m <...>! ()); capture= capture_arg}

  let capt_exp_of_typ m = {one_arg_matcher= match_typ (m <...>! ()); capture= capture_arg_exp}

  let typ1 : 'marker -> (unit, _, 'f, 'f, _, _) one_arg =
   fun m -> {one_arg_matcher= match_typ1 m; capture= no_capture}


  let typ2 : 'marker -> (unit, _, 'f, 'f, _, _) one_arg =
   fun m -> {one_arg_matcher= match_typ2 m; capture= no_capture}


  let typ3 : 'marker -> (unit, _, 'f, 'f, _, _) one_arg =
   fun m -> {one_arg_matcher= match_typ3 m; capture= no_capture}


  (* Function args end *)
  (** Matches if there is no function arguments left *)
  let no_args_left : (_, _, _) func_args_end =
    let match_empty_args = function Some (f, []) -> Matches f | _ -> DoesNotMatch in
    fun ~on_args args (f, capt) -> on_args capt (f, args) |> match_empty_args


  (** Matches any function arguments *)
  let any_func_args : (_, _, _) func_args_end =
   fun ~on_args args (f, capt) -> on_args capt (f, args) |> pre_map_opt ~f:fst


  (** If [func_args_end1] does not match, use [func_args_end2] *)
  let alternative_args_end
      : ('f_in, 'f_out, 'captured_types) func_args_end
        -> ('f_in, 'f_out, 'captured_types) func_args_end
        -> ('f_in, 'f_out, 'captured_types) func_args_end =
   fun func_args_end1 func_args_end2 ~on_args args f_capt ->
    match func_args_end1 ~on_args args f_capt with
    | DoesNotMatch ->
        func_args_end2 ~on_args args f_capt
    | otherwise ->
        otherwise


  (** Retries matching with another matcher *)
  let args_end_retry : _ matcher -> (_, _, _) func_args_end =
   fun m ~on_args:_ _args _f_capt -> RetryWith m


  (** Retries matching with another matcher if the function does not have the
    exact number/types of args *)
  let exact_args_or_retry : 'f matcher -> (_, _, _) func_args_end =
   fun m -> alternative_args_end no_args_left (args_end_retry m)


  let wrong_args_internal_error : _ matcher =
    let on_procname procname =
      Logging.(die InternalError)
        "Unexpected number/types of arguments for %a" Typ.Procname.pp procname
    in
    let on_c c _args = on_procname (C c) in
    let on_objc_cpp objc_cpp _args = on_procname (ObjC_Cpp objc_cpp) in
    {on_c; on_objc_cpp}


  let ( $! ) path_matcher () = args_begin path_matcher

  let ( >$! ) templ_matcher () = templ_matcher >! () $! ()

  let ( $*--> ) all_args_matcher f = make_matcher all_args_matcher f

  let ( $+! ) args_matcher func_arg = args_cons args_matcher func_arg

  let ( $!! ) one_arg () = make_arg mandatory_arg one_arg

  let ( $?! ) one_arg () = make_arg optional_arg one_arg

  let ( $+ ) args_matcher one_arg = args_matcher $+! (one_arg $!! ())

  let ( $+? ) args_matcher one_arg = args_matcher $+! (one_arg $?! ())

  let ( >$ ) templ_matcher one_arg = templ_matcher >$! () $+ one_arg

  let ( $* ) args_matcher func_args_end = args_end args_matcher func_args_end

  let ( $--> ) args_matcher f = args_matcher $* no_args_left $*--> f

  let ( $ ) name_matcher func_arg = name_matcher <...>! () $! () $+ func_arg

  let ( <>$ ) name_matcher one_arg = name_matcher <! () >$ one_arg

  let ( $+...$--> ) args_matcher f = args_matcher $* any_func_args $*--> f

  let ( >--> ) templ_matcher f = templ_matcher >$! () $+...$--> f

  let ( >$$--> ) templ_matcher f = templ_matcher >$! () $--> f

  let ( $$--> ) name_matcher f = name_matcher <...>! () $! () $--> f

  let ( <>$$--> ) name_matcher f = name_matcher <! () >$$--> f

  let ( &--> ) name_matcher f = name_matcher <...>! () $! () $+...$--> f

  let ( <>--> ) name_matcher f = name_matcher <! () >--> f

  let ( &::.*--> ) name_matcher f = name_matcher <...>! () &::.*! () $! () $+...$--> f

  let ( $!--> ) args_matcher f =
    args_matcher $* exact_args_or_retry wrong_args_internal_error $*--> f
end

module type NameCommon = sig
  include Common

  val ( >--> ) :
    ('f_in, 'f_out, 'captured_types, unit, 'markers, _) templ_matcher -> 'f_in -> 'f_out matcher

  val ( <>--> ) :
    ('f_in, 'f_out, 'captured_types, unit, 'markers) name_matcher -> 'f_in -> 'f_out matcher

  val ( &--> ) :
    ('f_in, 'f_out, 'captured_types, unit, 'markers) name_matcher -> 'f_in -> 'f_out matcher

  val ( &::.*--> ) :
    ('f_in, 'f_out, 'captured_types, unit, 'markers) name_matcher -> 'f_in -> 'f_out matcher
  (** After a name, accepts ALL template arguments, accepts ALL path tails (names, templates),
        accepts ALL function arguments, binds the function *)
end

module NameCommon = struct
  include Common

  type 'f matcher =
    {on_templated_name: templated_name -> 'f option; on_objc_cpp: objc_cpp -> 'f option}

  let make_matcher : ('f_in, 'f_out, _, _, _, non_empty) path_matcher -> 'f_in -> 'f_out matcher =
   fun m f ->
    let {on_templated_name; path_extra= PathNonEmpty {on_objc_cpp}}
          : ('f_in, 'f_out, _, _, _, non_empty) path_matcher =
      m
    in
    let on_templated_name templated_name =
      templated_name |> on_templated_name f |> Option.map ~f:fst
    in
    let on_objc_cpp objc_cpp = objc_cpp |> on_objc_cpp f |> Option.map ~f:fst in
    {on_templated_name; on_objc_cpp}


  let ( &-->! ) path_matcher f = make_matcher path_matcher f

  let ( >--> ) templ_matcher f = templ_matcher >! () &-->! f

  let ( <>--> ) name_matcher f = name_matcher <! () >--> f

  let ( &--> ) name_matcher f = name_matcher <...>! () &-->! f

  let ( &::.*--> ) name_matcher f = name_matcher <...>! () &::.*! () &-->! f
end

module ProcName = struct
  include NameCommon

  type 'f dispatcher = Typ.Procname.t -> 'f option

  let make_dispatcher : 'f matcher list -> 'f dispatcher =
   fun matchers ->
    let on_objc_cpp objc_cpp =
      List.find_map matchers ~f:(fun (matcher: _ matcher) -> matcher.on_objc_cpp objc_cpp)
    in
    let on_c (c: c) =
      let template_args = template_args_of_template_spec_info c.template_args in
      let templated_name = (c.name, template_args) in
      List.find_map matchers ~f:(fun (matcher: _ matcher) ->
          matcher.on_templated_name templated_name )
    in
    fun procname ->
      match procname with ObjC_Cpp objc_cpp -> on_objc_cpp objc_cpp | C c -> on_c c | _ -> None
end

module TypName = struct
  include NameCommon

  type 'f dispatcher = Typ.name -> 'f option

  let make_dispatcher : 'f matcher list -> 'f dispatcher =
   fun matchers typname ->
    match templated_name_of_class_name typname with
    | exception DoNotHandleJavaYet ->
        None
    | templated_name ->
        List.find_map matchers ~f:(fun (matcher: _ matcher) ->
            matcher.on_templated_name templated_name )
end