module Path = struct
  let trim_left s =
    let s = String.trim s in
    if String.starts_with ~prefix:"/" s then String.sub s 1 (String.length s - 1)
    else s

  let trim_right s =
    let s = String.trim s in
    if String.ends_with ~suffix:"/" s then String.sub s 0 (String.length s - 1)
    else s

  let add a b =
    let a = trim_right a in
    let b = trim_left b in
    Fmt.str "%s/%s" a b

  (*   let ( / ) = add *)
  let compare a b = String.compare (trim_right a) (trim_right b)
  let equal a b = 0 = compare a b
end

type t = Mkernel.Block.t Mfat.t

type entry = Mfat.entry = {
  name: string;
  is_dir: bool;
  size: int32;
}

module Fat = Mfat.Make (struct
  include Mkernel.Block

  let read = atomic_read
  let write = atomic_write
end)

include Fat

let create blk =
  match create blk with
  | Error (`Msg e) ->
      Fmt.epr "FAT file system initialization failure: %s@." e;
      exit 1
  | Ok fs -> fs

let map_err r = Result.map_error (fun (`Msg e) -> `Mfat e) r
let ls t p = ls t p |> map_err
let read t p = read t p |> map_err
let write t p s = write t p s |> map_err
let mkdir t p = mkdir t p |> map_err
let remove t p = remove t p |> map_err
let exists t p = exists t p
let stat t p = stat t p |> map_err

module type FS = sig
  val t : t
end