%%%-------------------------------------------------------------------
%%% Licensed to the Apache Software Foundation (ASF) under one
%%% or more contributor license agreements.  See the NOTICE file
%%% distributed with this work for additional information
%%% regarding copyright ownership.  The ASF licenses this file
%%% to you under the Apache License, Version 2.0 (the
%%% "License"); you may not use this file except in compliance
%%% with the License.  You may obtain a copy of the License at
%%%
%%%   http://www.apache.org/licenses/LICENSE-2.0
%%%
%%% Unless required by applicable law or agreed to in writing,
%%% software distributed under the License is distributed on an
%%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
%%% KIND, either express or implied.  See the License for the
%%% specific language governing permissions and limitations
%%% under the License.
%%%
%%%-------------------------------------------------------------------

%%% @doc otter_lib module. Exports common library functions for the otter
%%% otter_srv (otter server) applications.
%%% @end
%%%-------------------------------------------------------------------


-module(otter_lib).
-export([
         id/0,
         ip_to_i32/1,
         i32_to_ip/1,
         timestamp/0,
         to_bin/1
         ]).


-include("otter.hrl").

%%---------------------------------------------------------------------
%% @doc Convert ipv4 tuple `{A,B,C,D}' to 32 bit integer
%% @end
%%---------------------------------------------------------------------
-spec ip_to_i32(IP4 :: ip4()) -> integer().
ip_to_i32({A,B,C,D}) ->
    <<Ip:32>> = <<A,B,C,D>>,
    Ip.

%%---------------------------------------------------------------------
%% @doc Convert a 32 bit binary to ipv4 tuple `{A,B,C,D}'
%% @end
%%---------------------------------------------------------------------
-spec i32_to_ip(I32 :: binary()) -> ip4().
i32_to_ip(<<A,B,C,D>>) ->
    {A,B,C,D}.

%%---------------------------------------------------------------------
%% @doc UNIX Timestamp in microseconds
%% @end
%%---------------------------------------------------------------------
-spec timestamp() -> integer().
timestamp() ->
    {MeS, S, MuS} = os:timestamp(),
    (MeS*1000000+S)*1000000+MuS.

%%---------------------------------------------------------------------
%% @doc Generate 64 bit integer random ID
%% @end
%%---------------------------------------------------------------------
-spec id() -> integer().
id() ->
    <<Id:64>> = crypto:strong_rand_bytes(8),
    Id.

%%---------------------------------------------------------------------
%% @doc Convert various data types to binary format with unicode support
%% where applicable
%% @end
%%---------------------------------------------------------------------
-spec to_bin(term()) -> binary().
to_bin(Int) when is_integer(Int)->
    integer_to_binary(Int);
to_bin(Atom) when is_atom(Atom) ->
    atom_to_binary(Atom, 'utf8');
to_bin(List) when is_list(List) ->
    unicode:characters_to_binary(List);
to_bin(Binary) when is_binary(Binary) ->
    Binary;
to_bin(Fun) when is_function(Fun, 0) ->
    to_bin(Fun());
to_bin(Value) ->
    unicode:characters_to_binary(io_lib:format("~1024p", [Value])).