/ucengine/src/core/utils.erl

%%
%%  U.C.Engine - Unified Collaboration Engine
%%  Copyright (C) 2011 af83
%%
%%  This program is free software: you can redistribute it and/or modify
%%  it under the terms of the GNU Affero General Public License as published by
%%  the Free Software Foundation, either version 3 of the License, or
%%  (at your option) any later version.
%%
%%  This program 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 Affero General Public License for more details.
%%
%%  You should have received a copy of the GNU Affero General Public License
%%  along with this program.  If not, see <http://www.gnu.org/licenses/>.
%%
-module(utils).

-include("uce.hrl").
-include_lib("yaws/include/yaws_api.hrl").

-export([now/0,

         random/0,
         random/1,
         get_values/2,
         get/2,
         get/3,
         proplist_merge/2]).

%% Get current timestamp
now() ->
    {Mega,Sec,Micro} = erlang:now(),
    erlang:round(((Mega*1000000+Sec)*1000000+Micro)/1000).

random() ->
    random(32).
random(0) ->
    [];
random(Length) ->
    [crypto:rand_uniform(48,58)] ++ random(Length - 1).

get(Params, Key) when is_atom(Key) ->
    [Result] = get(Params, [Key]),
    Result;
get(Params, Keys) ->
    get(Params, Keys, none).

get(Params, Keys, Default) when is_atom(Default) ->
    get(Params, Keys, lists:map(fun(_Elem) ->
                                        Default
                                end,
                                Keys));
get(_Params, [], []) ->
    [];
get(Params, [Key|Keys], [Default|Defaults]) ->
    ValueList = case lists:keysearch(Key, 1, Params) of
                    {value, {Key, Value}} ->
                        [Value];
                    false ->
                        [Default]
                end,
    ValueList ++ get(Params, Keys, Defaults).

get_values(Proplist, Keys) ->
    lists:map(fun({Name, Default}) ->
                proplists:get_value(Name, Proplist, Default)
              end, Keys).


%% Merge two proplist
proplist_merge(ProplistOne, ProplistTwo) ->
    lists:foldl(fun(Elem, Acc) ->
        case Elem of
            {Key, Value} ->
                case proplists:is_defined(Key, ProplistOne) of
                    true ->
                        Acc;
                    false -> Acc ++ [{Key, Value}]
                end;
            Key ->
                case proplists:is_defined(Key, ProplistOne) of
                    true ->
                        Acc;
                    false -> Acc ++ [Key]
                end
        end
    end,
        ProplistOne, ProplistTwo).

-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").

get_values_test() ->
    ?assertEqual(["chuck", "norris", rocks], get_values([{firstname, "chuck"}, {lastname, "norris"}], [{firstname, ""}, {lastname, ""}, {def, rocks}])).

merge_test() ->
    A = [{firstname, "Chuck"}, {lastname, "Norris"}, alive],
    B = [{firstname, "Robert"}, {shoes, "santiags"}, {lastname, "Norris2"}],
    C = proplist_merge(A, B),
    ?assertEqual("Chuck", proplists:get_value(firstname, C)),
    ?assertEqual("Chuck", proplists:get_value(firstname, C)),
    ?assertEqual("Norris", proplists:get_value(lastname, C)),
    ?assertEqual(true, proplists:get_value(alive, C)).
-endif.