(* Copyright (C) 2017--2018  Petter A. Urkedal <paurkedal@gmail.com>
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version, with the LGPL-3.0 Linking Exception.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * and the LGPL-3.0 Linking Exception along with this library.  If not, see
 * <http://www.gnu.org/licenses/> and <https://spdx.org>, respectively.
 *)

let debug =
  try bool_of_string (Sys.getenv "CAQTI_DEBUG_DYNLOAD")
  with Not_found -> false

let backend_predicates () =
  (match Sys.backend_type with
   | Sys.Native -> ["native"]
   | Sys.Bytecode -> ["byte"]
   | Sys.Other _ -> [])

let init = lazy begin
  let predicates = backend_predicates () in
  Findlib.init ();
  Findlib.record_package_predicates predicates;
  List.iter (Findlib.record_package Record_core)
            (Findlib.package_deep_ancestors predicates ["caqti"]);
  if debug then
    Printf.eprintf "\
        [DEBUG] Caqti_dynload: recorded_predicates = %s\n\
        [DEBUG] Caqti_dynload: recorded_packages.core = %s\n\
        [DEBUG] Caqti_dynload: recorded_packages.load = %s\n%!"
      (String.concat " " (Findlib.recorded_predicates ()))
      (String.concat " " (Findlib.recorded_packages Record_core))
      (String.concat " " (Findlib.recorded_packages Record_load))
end

let () = Caqti_platform.Connector.define_loader @@ fun pkg ->
  Lazy.force init;
  if debug then
    Printf.eprintf "[DEBUG] Caqti_dynload: requested package: %s\n" pkg;
  (try Ok (Fl_dynload.load_packages ~debug [pkg]) with
   | Dynlink.Error err -> Error (Dynlink.error_message err)
   | Findlib.No_such_package (_pkg, info) -> Error info)

module Weak_ = struct include Weak end (* for caqti-driver-mariadb *)