#!/usr/bin/env escript
%% -*- erlang -*-
%%! -pa ebin -pa ../lager/ebin -pa ../lager/deps/goldrush/ebin

-mode(compile).

gentestdata(Size) ->
    [{crypto:hash(sha256, <<E:32, 0:32>>), crypto:hash(sha256, <<E:32, 1:32>>)} || E <- lists:seq(0, Size-1)].

timeprint(Time) ->
    io_lib:format("~.2fs", [Time/1000000]).

testinit(Filename) ->
    permdb:start_link(testdb, Filename).

teststop() ->
    permdb:stop(testdb).

constructdata(VSeed, Size) ->
    A = binary:copy(VSeed, Size div 32),
    B = binary:part(VSeed, 0, Size rem 32),
    <<A/binary, B/binary>>.

getvalue_loop([], _Port, _Datasize) ->
    none;
getvalue_loop([{K, VSeed}|Rest], Port, Datasize) ->
    V = case VSeed of
            noentry ->
                noentry;
            _ ->
                constructdata(VSeed, Datasize)
        end,
    case permdb:getvalue(testdb, K) of
        V ->
            getvalue_loop(Rest, Port, Datasize);
        VOther ->
            io:format("expected: ~p got: ~p~nkey: ~p~n", [V, VOther, K]),
            exit(mismatch)
    end.

addvalue_loop([], _Port, _Datasize) ->
    none;
addvalue_loop([{K, VSeed}|Rest], Port, Datasize) ->
    V = constructdata(VSeed, Datasize),
    case permdb:addvalue(testdb, K, V) of
        ok ->
            addvalue_loop(Rest, Port, Datasize);
        Other ->
            io:format("expected: 0 or 1 got: ~p~n", [Other]),
            exit(mismatch)
    end.

testget(_Filename, TestData, Datasize) ->
    getvalue_loop(TestData, none, Datasize),
    ok.

testadd(_Filename, TestData, Datasize) ->
    addvalue_loop(TestData, none, Datasize),
    case permdb:commit(testdb) of
        <<0>> ->
            ok;
        Other ->
            io:format("commit expected: 0 got: ~p~n", [Other]),
            exit(mismatch)
    end.

stop() ->
    teststop(),
    receive
    after
        100 ->
            ok
    end.

runbench(Fun, Size, Verb) ->
    {Time2, ok} = timer:tc(Fun),
    io:format("~s ~p entries: ~s ~.1f entries/s (~.2f microseconds)~n", [Verb, Size, timeprint(Time2), Size*1000000/Time2, Time2/Size]).

chunk([], N) ->
    [];
chunk(List, N) ->
    First = lists:sublist(List, N),
    Rest = lists:nthtail(N, List),
    [First | chunk(Rest, N)].

main([]) ->
    {ok, Cwd} = file:get_cwd(),
    code:add_path(Cwd ++ "/ebin"),
    Size = 20000,
    Datasize = 1000,
    ChunkSize = 1000,
    Filename = "testpermdb",
    file:delete(Filename),
    file:delete(Filename ++ ".idx"),
    {Time1, TestData} = timer:tc(fun () -> gentestdata(Size) end),
    TestDataLists = chunk(TestData, ChunkSize),
    io:format("Init with ~p entries: ~s~n", [Size, timeprint(Time1)]),
    testinit(Filename),
    runbench(fun () ->
                     lists:foreach(fun (E) ->
                                           testadd(Filename, E, Datasize)
                                   end, TestDataLists)
             end, Size, "Add"),
    runbench(fun () -> testget(Filename, TestData, Datasize) end, Size, "Get"),
    stop(),

    testinit(Filename),
    runbench(fun () -> testget(Filename, TestData, Datasize) end, Size, "Get"),
    stop(),

    file:delete(Filename ++ ".idx"),

    testinit(Filename),
    runbench(fun () -> testget(Filename, [hd(TestData)], Datasize) end, Size, "Rebuild"),
    runbench(fun () -> testget(Filename, TestData, Datasize) end, Size, "Get"),
    stop(),

    ok.