module Octal = Octal
module Tar = Tar

let tar_path = if Array.length Sys.argv < 2 then
                 failwith "No tar path supplied"
               else Array.get Sys.argv 1

let (root, tar_ch) = Tar.parse_tar tar_path
let () = Tar.print_tree "" root

let rec getattr path =
  match Tar.find path root with
  | None -> raise (Unix.Unix_error (Unix.ENOENT, "hi1", "hi1"))
  | Some (File (_, md)) -> md
  | Some (Directory (_, md)) -> md
  | Some (InferredDirectory (_, md)) -> md
  | Some (Symlink (_, md)) -> md
  | Some (Hardlink (p)) -> getattr p

let rec readdir path _i =
  match Tar.find path root with
  | None -> raise (Unix.Unix_error (Unix.ENOENT, "234", "234"))
  | Some (Hardlink linked_path)
  | Some (Symlink (linked_path, _)) ->
     if String.equal linked_path path then
       raise (Unix.Unix_error (Unix.ENOENT, "read", path))
     else
       readdir linked_path _i
  
  | Some (File (_, _)) -> raise (Unix.Unix_error (Unix.ENOENT, "345", "345"))
  | Some (InferredDirectory (children, _))
  | Some (Directory (children, _)) ->
     ["."; ".."] @ (List.map (fun (name, _) -> name) (Tar.NameMap.to_list children))

(* There seems to be a bug here - the amount argument given to this function
   is NOT the correct requested amount. The buffer size is correct though
   so I'm taking that as the source of truth.
 *)
let rec read path buf offset _amount =
(*
  let () = Printf.printf "PARAMS %d %d %d\n" (Int64.to_int offset) amount (Bigarray.Array1.dim buf) in
  let () = Out_channel.flush_all () in*)
  match Tar.find path root with
  | None -> raise (Unix.Unix_error (Unix.ENOENT, "read", path))
  | Some (Hardlink linked_path) 
  | Some (Symlink (linked_path, _)) ->
     if String.equal linked_path path then
       raise (Unix.Unix_error (Unix.ENOENT, "read", path))
     else
     read linked_path buf offset _amount
  | Some (File (fo, md)) ->
     (let (file_buf,read) = (Tar.read_file (File (fo, md)) tar_ch offset (Bigarray.Array1.dim buf)) in
      Bytes.iteri (fun i c -> Bigarray.Array1.set buf i c) file_buf;
     read)
  | _ -> raise (Unix.Unix_error (Unix.EISDIR, "read", path))

let readlink path =
  match Tar.find path root with
  | Some (Symlink (path, _)) ->
     path
  | _ -> raise (Unix.Unix_error (Unix.ENOENT, "readlink", path))

let _ =
  let args = Array.append  (Array.sub Sys.argv 1 ((Array.length Sys.argv) - 1)) [|"-o";"use_ino"|] in
  Fuse.main args
    {
      Fuse.default_operations with
      getattr = getattr;
      readdir = readdir;
      read = read;
      readlink = readlink;
    }