%%% --------------------------------------------------
%%% @author Benjamin Peinhardt <benjaminpeinhardt@gmail.com>
%%% @doc Erlang ffi glue code for the simplifile Gleam package.
%%% @end
%%% --------------------------------------------------

-module(simplifile_erl).

%% API
-export([
    read_file/1,
    append_file/2,
    write_file/2,
    delete_file/1,
    delete_directory/1,
    recursive_delete/1,
    list_directory/1,
    make_directory/1,
    is_file/1,
    create_dir_all/1,
    rename_file/2,
    set_permissions/2
]).

%% A macro for checking whether the error returned is one of the atoms for a posixe error.
-define(is_posix_error(Error),
    Error =:= eacces orelse Error =:= eagain orelse Error =:= ebadf orelse
        Error =:= ebadmsg orelse Error =:= ebusy orelse Error =:= edeadlk orelse
        Error =:= edeadlock orelse Error =:= edquot orelse Error =:= eexist orelse
        Error =:= efault orelse Error =:= efbig orelse Error =:= eftype orelse
        Error =:= eintr orelse Error =:= einval orelse Error =:= eio orelse
        Error =:= eisdir orelse Error =:= eloop orelse Error =:= emfile orelse
        Error =:= emlink orelse Error =:= emultihop orelse Error =:= enametoolong orelse
        Error =:= enfile orelse Error =:= enobufs orelse Error =:= enodev orelse
        Error =:= enolck orelse Error =:= enolink orelse Error =:= enoent orelse
        Error =:= enomem orelse Error =:= enospc orelse Error =:= enosr orelse
        Error =:= enostr orelse Error =:= enosys orelse Error =:= enotblk orelse
        Error =:= enotdir orelse Error =:= enotsup orelse Error =:= enxio orelse
        Error =:= eopnotsupp orelse Error =:= eoverflow orelse Error =:= eperm orelse
        Error =:= epipe orelse Error =:= erange orelse Error =:= erofs orelse
        Error =:= espipe orelse Error =:= esrch orelse Error =:= estale orelse
        Error =:= etxtbsy orelse Error =:= exdev
).

%% Only return the error if it's a posix error. Also converts ok to {ok, nil},
%% as gleam doesn't have atoms.
posix_result(Result) ->
    case Result of
        ok -> {ok, nil};
        {ok, Value} -> {ok, Value};
        {error, Reason} when ?is_posix_error(Reason) -> {error, Reason}
    end.

%% Read the binary contents of a file
read_file(Filename) ->
    posix_result(file:read_file(Filename)).

%% Write bytes to a file
write_file(Contents, Filename) ->
    posix_result(file:write_file(Filename, Contents)).

%% Append bytes to a file
append_file(Contents, Filename) ->
    posix_result(file:write_file(Filename, Contents, [append])).

%% Delete the file at the given path
delete_file(Filename) ->
    posix_result(file:delete(Filename)).

%% Create a directory at the given path. Missing parent directories are not created.
make_directory(Dir) ->
    posix_result(file:make_dir(Dir)).

%% List the contents of a directory
list_directory(Dir) ->
    case file:list_dir(Dir) of
        {ok, Filenames} ->
            {ok, [list_to_binary(Filename) || Filename <- Filenames]};
        {error, Reason} when ?is_posix_error(Reason) ->
            {error, Reason}
    end.

%% Delete a directory at the given path. Directory must be empty.
delete_directory(Dir) ->
    posix_result(file:del_dir(Dir)).

%% Deletes a file/directory and everything in it.
recursive_delete(Dir) ->
    posix_result(file:del_dir_r(Dir)).

%% Checks whether a given file exists and is a file (as opposed to a directory)
is_file(Filename) ->
    not (file:read_file_info(Filename) == {error, enoent}) and not filelib:is_dir(Filename).

%% Creates the entire path for a given directory to exist
create_dir_all(Filename) ->
    posix_result(filelib:ensure_dir(Filename)).

%% Move file from one path to another
rename_file(Source, Destination) ->
    posix_result(file:rename(Source, Destination)).

%% Set the permissions for the given file.
set_permissions(Filename, Permissions) ->
    posix_result(file:change_mode(Filename, Permissions)).