-module(gm_ctflow_SUITE).

-export([ all/0
        , groups/0
        , init_per_suite/1
        , end_per_suite/1
        , init_per_group/2
        , end_per_group/2
        , init_per_testcase/2
        , end_per_testcase/2
        ]).

%% test cases
-export([ put_a/1
        , get_a/1
        , erase_a/1
        , init_counter/1
        , incr/1
        , check1/1
        , check2/1
        , check3/1
        , init_worker/1
        , append/1
        , checkl1/1
        , checkl2/1
        , checkl3/1
        , reset/1
        , reset_flow/1
        , status/1
        ]).

-include_lib("stdlib/include/assert.hrl").

all() ->
    [
      {group, state}
    , {group, statefuns}
    , {group, workers}
    , {group, reset}
    ].

groups() ->
    [ {state, [sequence], [ put_a
                          , get_a
                          , erase_a
                          ]}
    , {statefuns, [sequence], [ init_counter
                              , incr
                              , check1       %% state = 1
                              , incr
                              , check2       %% state = 2
                              , incr
                              , check3       %% state = 3
                              , status
                              ]}
    , {workers, [sequence], [ init_counter
                            , init_worker
                            , append
                            , checkl1        %% [A0]
                            , append
                            , checkl2        %% [A0, A1]
                            , append
                            , checkl3        %% [A0, A1, A2]
                            , status
                            ]}
    , {reset, [sequence], [ init_counter
                          , init_worker
                          , append           %% also increments
                          , check1           %% so, state = 1
                          , checkl1
                          , reset_flow
                          , checkl1          %% flow 'my_list' unaffected
                          , init_counter
                          , incr
                          , check1
                          , status ]}
    ].

init_per_suite(Config) ->
    Config.

end_per_suite(_Config) ->
    ok.

init_per_group(_Grp, Config) ->
    ok = application:start(gm_ctflow, permanent),
    Config.

end_per_group(_Grp, _Config) ->
    ok = application:stop(gm_ctflow),
    ok.

init_per_testcase(_Case, Config) ->
    gm_ctflow:status(),
    Config.

end_per_testcase(_Case, _Config) ->
    gm_ctflow:status(),
    ok.

%% ======================================================================
%% State update commands

put_a(_Cfg) ->
    ok = gm_ctflow:put(a, 1),
    ?assertMatch(1, gm_ctflow:get(a)).

get_a(_Cfg) ->
    ?assertMatch(1, gm_ctflow:get(a)).

erase_a(_Cfg) ->
    ok = gm_ctflow:erase(a),
    ?assertException(error, {no_such_key,a}, gm_ctflow:get(a)),
    ?assertMatch(undefined, gm_ctflow:get(a, undefined)).

%% ======================================================================
%% This is our 'ctflow_fun' instance, which floats above some simple
%% test cases. In this test suite, we only exercise the flow funs, but
%% in a normal test suite, we would use them for information that isn't
%% easily threaded through the sequence of cases otherwise.
%%
init_counter(_Cfg) ->
    gm_ctflow:status(),
    gm_ctflow_fun:new(my_counter, fun ctr/2, 0),
    ok.

incr(_Cfg) ->
    Res = gm_ctflow_fun:call(my_counter, incr),
    ?assert(is_integer(Res)),
    ok.

check1(_Cfg) -> check_(1).
check2(_Cfg) -> check_(2).
check3(_Cfg) -> check_(3).

check_(N) ->
    ?assertEqual(N, gm_ctflow_fun:get_state(my_counter)),
    ok.

%% This is the actual fun
ctr(incr, N) ->
    NewN = N+1,
    {ok, NewN, NewN}.

reset_flow(_Cfg) ->
    gm_ctflow:reset_flow(my_counter).

status(_Cfg) ->
    gm_ctflow:status().

%% ======================================================================
%% Here, we make use of the `gm_ctflow_worker` it's a complete process
%% (a gen_server, whose logic we instrument with the fun we provice).
%% For a bit of variety, we re-use the `ctr` fun, and at the same time,
%% ensure that stopping and restarting the `gm_ctflow` app clears the state.
%% (See `init_per_group/2` and `end_per_group/2`).
%%
%% Note that the worker is initiated using a fun/0, which in its turn is
%% expected to provide the fun/3 for the gen_server callback logic.
%% This is so that we can actually perform some actions at init time.
%%
init_worker(_Cfg) ->
    {ok, Pid} = gm_ctflow_worker:start(my_list, fun() -> {ok, fun lfun/3, []} end),
    true = is_pid(Pid),
    ok.

append(_Cfg) ->
    C = gm_ctflow_fun:call(my_counter, incr),
    Res = gm_ctflow_worker:call(my_list, {append, {a, C}}),
    ?assert(is_list(Res)),
    ok.

checkl1(_Cfg) -> checkl_([{a,1}]).
checkl2(_Cfg) -> checkl_([{a,1},{a,2}]).
checkl3(_Cfg) -> checkl_([{a,1},{a,2},{a,3}]).

checkl_(L) ->
    ?assertEqual(L, gm_ctflow_worker:get_state(my_list)),
    ok.

lfun({call,_From}, {append, Item}, L) ->
    NewL = L ++ [Item],
    {reply, NewL, NewL}.

reset(_Cfg) ->
    gm_ctflow:reset().