-module(logic_recurrence_tests).
-include_lib("eunit/include/eunit.hrl").

logic_recurrence_test_() ->
  [
    {"Parse RRULE test", fun test_parse_rrule/0},
    {"Validate RRULE test", fun test_validate_rrule/0},
    {"Generate daily occurrences test", fun test_daily_occurrences/0},
    {"Generate weekly occurrences test", fun test_weekly_occurrences/0},
    {"Generate monthly occurrences test", fun test_monthly_occurrences/0},
    {"Generate with count limit test", fun test_count_limit/0},
    {"Generate with until limit test", fun test_until_limit/0}
  ].

test_parse_rrule() ->
  RRule = #{
    <<"freq">> => <<"WEEKLY">>,
    <<"interval">> => 2,
    <<"until">> => <<"2026-12-31T00:00:00Z">>,
    <<"byday">> => [<<"MO">>, <<"WE">>, <<"FR">>]
  },

  {ok, Parsed} = logic_recurrence:parse_rrule(RRule),
  ?assertEqual(<<"WEEKLY">>, maps:get(freq, Parsed)),
  ?assertEqual(2, maps:get(interval, Parsed)),
  ?assertEqual(<<"2026-12-31T00:00:00Z">>, maps:get(until, Parsed)),
  ?assertEqual([<<"MO">>, <<"WE">>, <<"FR">>], maps:get(byday, Parsed)).

test_validate_rrule() ->
  ValidRule = #{
    freq => <<"DAILY">>,
    interval => 1
  },
  ?assert(logic_recurrence:validate_rrule(ValidRule)),

  InvalidFreq = #{
    freq => <<"YEARLY">>,
    interval => 1
  },
  ?assertNot(logic_recurrence:validate_rrule(InvalidFreq)),

  InvalidInterval = #{
    freq => <<"DAILY">>,
    interval => 0
  },
  ?assertNot(logic_recurrence:validate_rrule(InvalidInterval)).

test_daily_occurrences() ->
  StartTime = {{2026, 4, 20}, {10, 0, 0}},
  RRule = #{
    freq => <<"DAILY">>,
    interval => 1
  },
  RangeEnd = {{2026, 4, 25}, {10, 0, 0}},

  Occurrences = logic_recurrence:generate_occurrences(StartTime, RRule, RangeEnd),
  ?assertEqual(6, length(Occurrences)),
  ?assertEqual({{2026, 4, 20}, {10, 0, 0}}, lists:nth(1, Occurrences)),
  ?assertEqual({{2026, 4, 25}, {10, 0, 0}}, lists:nth(6, Occurrences)).

test_weekly_occurrences() ->
  StartTime = {{2026, 4, 20}, {10, 0, 0}},  % Monday
  RRule = #{
    freq => <<"WEEKLY">>,
    interval => 1
  },
  RangeEnd = {{2026, 5, 11}, {10, 0, 0}},

  Occurrences = logic_recurrence:generate_occurrences(StartTime, RRule, RangeEnd),
  ?assertEqual(4, length(Occurrences)),
  ?assertEqual({{2026, 4, 20}, {10, 0, 0}}, lists:nth(1, Occurrences)),
  ?assertEqual({{2026, 5, 11}, {10, 0, 0}}, lists:nth(4, Occurrences)).

test_monthly_occurrences() ->
  StartTime = {{2026, 4, 20}, {10, 0, 0}},
  RRule = #{
    freq => <<"MONTHLY">>,
    interval => 1
  },
  RangeEnd = {{2026, 7, 20}, {10, 0, 0}},

  Occurrences = logic_recurrence:generate_occurrences(StartTime, RRule, RangeEnd),
  ?assertEqual(4, length(Occurrences)),
  ?assertEqual({{2026, 4, 20}, {10, 0, 0}}, lists:nth(1, Occurrences)),
  ?assertEqual({{2026, 7, 20}, {10, 0, 0}}, lists:nth(4, Occurrences)).

test_count_limit() ->
  StartTime = {{2026, 4, 20}, {10, 0, 0}},
  RRule = #{
    freq => <<"DAILY">>,
    interval => 1,
    count => 3
  },
  RangeEnd = {{2026, 12, 31}, {10, 0, 0}},

  Occurrences = logic_recurrence:generate_occurrences(StartTime, RRule, RangeEnd),
  ?assertEqual(3, length(Occurrences)).

test_until_limit() ->
  StartTime = {{2026, 4, 20}, {10, 0, 0}},
  RRule = #{
    freq => <<"DAILY">>,
    interval => 1,
    until => <<"2026-04-22T10:00:00Z">>
  },
  RangeEnd = {{2026, 12, 31}, {10, 0, 0}},

  Occurrences = logic_recurrence:generate_occurrences(StartTime, RRule, RangeEnd),
  % 20, 21, 22 апреля = 3 дня
  ?assertEqual(3, length(Occurrences)).