(*
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *)

open Loc_collections
module Scope_api = Scope_api.With_Loc

let local_find_refs ast loc =
  Scope_api.(
    let scope_info = Scope_builder.program ast in
    let all_uses = all_uses scope_info in
    let matching_uses = LocSet.filter (fun use -> Loc.contains use loc) all_uses in
    let num_matching_uses = LocSet.cardinal matching_uses in
    if num_matching_uses = 0 then
      None
    else if num_matching_uses > 1 then
      (* This is unlikely enough that we can just throw *)
      failwith "Multiple identifiers were unexpectedly matched"
    else
      let use = LocSet.choose matching_uses in
      let def = def_of_use scope_info use in
      let sorted_locs = LocSet.elements @@ uses_of_def scope_info ~exclude_def:false def in
      let name = Def.(def.actual_name) in
      let sorted_locs = Base.List.map ~f:(fun loc -> (FindRefsTypes.Local, loc)) sorted_locs in
      Some ((name, sorted_locs), Nel.hd def.Def.locs))
