[OCPP] Fix incorrect composite schedule when duration is zero

lib/everest/ocpp/lib/ocpp/v16/profile.cpp

@@ -425,7 +425,8 @@ IntermediateProfile generate_profile_from_periods(std::vector<period_entry_t>& p
     IntermediateProfile combined{};
     DateTime current = now;
 
-    while (current < end) {
+    // run calculation at least once especially where current >= end
+    do {
         // find schedule to use for time: current
         DateTime earliest = end;
         DateTime next_earliest = end;
@@ -476,7 +477,7 @@ IntermediateProfile generate_profile_from_periods(std::vector<period_entry_t>& p
                 current = next_earliest;
             }
         }
-    }
+    } while (current < end);
 
     return combined;
 }

lib/everest/ocpp/lib/ocpp/v16/smart_charging.cpp

@@ -208,8 +208,14 @@ ChargingSchedule SmartChargingHandler::calculate_composite_schedule(const ocpp::
                                                                     const std::int32_t evse_id,
                                                                     ChargingRateUnit charging_rate_unit,
                                                                     bool is_offline, bool simulate_transaction_active) {
+    // handle edge case where start_time > end_time
+    auto start_time_w = start_time;
+    if (start_time_w > end_time) {
+        start_time_w = end_time;
+    }
+
     const auto enhanced_composite_schedule = this->calculate_enhanced_composite_schedule(
-        start_time, end_time, evse_id, charging_rate_unit, is_offline, simulate_transaction_active);
+        start_time_w, end_time, evse_id, charging_rate_unit, is_offline, simulate_transaction_active);
     ChargingSchedule composite_schedule;
     composite_schedule.chargingRateUnit = enhanced_composite_schedule.chargingRateUnit;
     composite_schedule.duration = enhanced_composite_schedule.duration;

lib/everest/ocpp/lib/ocpp/v2/functional_blocks/smart_charging.cpp

@@ -550,12 +550,18 @@ std::vector<IntermediateProfile> generate_evse_intermediates(std::vector<Chargin
 }
 } // namespace
 
-CompositeSchedule SmartCharging::calculate_composite_schedule(const ocpp::DateTime& start_time,
+CompositeSchedule SmartCharging::calculate_composite_schedule(const ocpp::DateTime& start_t,
                                                               const ocpp::DateTime& end_time,
                                                               const std::int32_t evse_id,
                                                               ChargingRateUnitEnum charging_rate_unit, bool is_offline,
                                                               bool simulate_transaction_active) {
 
+    // handle edge case where start_time > end_time
+    auto start_time = start_t;
+    if (start_time > end_time) {
+        start_time = end_time;
+    }
+
     const CompositeScheduleConfig config{this->context.device_model, is_offline};
 
     std::optional<ocpp::DateTime> session_start{};

lib/everest/ocpp/lib/ocpp/v2/profile.cpp

@@ -408,7 +408,8 @@ IntermediateProfile generate_profile_from_periods(std::vector<period_entry_t>& p
     IntermediateProfile combined{};
     DateTime current = now;
 
-    while (current < end) {
+    // run calculation at least once especially where current >= end
+    do {
         // find schedule to use for time: current
         DateTime earliest = end;
         DateTime next_earliest = end;
@@ -477,7 +478,7 @@ IntermediateProfile generate_profile_from_periods(std::vector<period_entry_t>& p
                 current = next_earliest;
             }
         }
-    }
+    } while (current < end);
 
     return combined;
 }

lib/everest/ocpp/tests/lib/ocpp/v16/test_composite_schedule.cpp

@@ -928,5 +928,77 @@ TEST_F(CompositeScheduleTestFixture, TxDefaultConnector0) {
                                      PeriodEquals(350, 10000.0F)));
 }
 
+TEST_F(CompositeScheduleTestFixture, ZeroDuration) {
+    // test relating to libocpp issue 1169
+    // incorrect composite schedule when duration is zero
+
+    // using absolute schedule with limit 2000.0, starting 2024-01-17T18:04:00.000Z
+    // default limit is 33120.0
+
+    auto handler = create_smart_charging_handler(1, false);
+    ChargingProfile profile_tx_default_1 = get_charging_profile_from_file("TxProfile_03_Absolute.json");
+
+    handler->add_tx_default_profile(profile_tx_default_1, 0);
+
+    // start 1 minute into the profile
+    const DateTime start_time = ocpp::DateTime("2024-01-17T18:05:00.000Z");
+    const DateTime end_time = ocpp::DateTime("2024-01-17T18:05:01.000Z");
+    const auto expected_limit = 2000.0F;
+
+    // check with end time and a corresponding duration of 1 second
+    auto result_con0 =
+        handler->calculate_composite_schedule(start_time, end_time, STATION_WIDE_ID, ChargingRateUnit::W, false, true);
+
+    EXPECT_EQ(result_con0.startSchedule, start_time);
+    EXPECT_EQ(result_con0.duration, 1);
+    EXPECT_EQ(result_con0.chargingRateUnit, ChargingRateUnit::W);
+
+    EXPECT_THAT(result_con0.chargingSchedulePeriod, testing::ElementsAre(PeriodEquals(0, expected_limit)));
+
+    auto result_con1 = handler->calculate_composite_schedule(start_time, end_time, 1, ChargingRateUnit::W, false, true);
+
+    EXPECT_EQ(result_con1.startSchedule, start_time);
+    EXPECT_EQ(result_con1.duration, 1);
+    EXPECT_EQ(result_con1.chargingRateUnit, ChargingRateUnit::W);
+
+    EXPECT_THAT(result_con1.chargingSchedulePeriod, testing::ElementsAre(PeriodEquals(0, expected_limit)));
+
+    // Now with duration of 0 seconds
+    result_con0 = handler->calculate_composite_schedule(start_time, start_time, STATION_WIDE_ID, ChargingRateUnit::W,
+                                                        false, true);
+
+    EXPECT_EQ(result_con0.startSchedule, start_time);
+    EXPECT_EQ(result_con0.duration, 0);
+    EXPECT_EQ(result_con0.chargingRateUnit, ChargingRateUnit::W);
+
+    EXPECT_THAT(result_con0.chargingSchedulePeriod, testing::ElementsAre(PeriodEquals(0, expected_limit)));
+
+    result_con1 = handler->calculate_composite_schedule(start_time, start_time, 1, ChargingRateUnit::W, false, true);
+
+    EXPECT_EQ(result_con1.startSchedule, start_time);
+    EXPECT_EQ(result_con1.duration, 0);
+    EXPECT_EQ(result_con1.chargingRateUnit, ChargingRateUnit::W);
+
+    EXPECT_THAT(result_con1.chargingSchedulePeriod, testing::ElementsAre(PeriodEquals(0, expected_limit)));
+
+    // Now with duration of -1 second (treated as an instantaneous 0 duration)
+    result_con0 =
+        handler->calculate_composite_schedule(end_time, start_time, STATION_WIDE_ID, ChargingRateUnit::W, false, true);
+
+    EXPECT_EQ(result_con0.startSchedule, start_time);
+    EXPECT_EQ(result_con0.duration, 0);
+    EXPECT_EQ(result_con0.chargingRateUnit, ChargingRateUnit::W);
+
+    EXPECT_THAT(result_con0.chargingSchedulePeriod, testing::ElementsAre(PeriodEquals(0, expected_limit)));
+
+    result_con1 = handler->calculate_composite_schedule(end_time, start_time, 1, ChargingRateUnit::W, false, true);
+
+    EXPECT_EQ(result_con1.startSchedule, start_time);
+    EXPECT_EQ(result_con1.duration, 0);
+    EXPECT_EQ(result_con1.chargingRateUnit, ChargingRateUnit::W);
+
+    EXPECT_THAT(result_con1.chargingSchedulePeriod, testing::ElementsAre(PeriodEquals(0, expected_limit)));
+}
+
 } // namespace v16
 } // namespace ocpp

lib/everest/ocpp/tests/lib/ocpp/v2/test_composite_schedule.cpp

@@ -1201,4 +1201,51 @@ TEST_F(CompositeScheduleTestFixtureV2, TxDefaultConnector0) {
                                      PeriodEquals(350, 10000.0F)));
 }
 
+TEST_F(CompositeScheduleTestFixtureV2, ZeroDuration) {
+    // test relating to libocpp issue 1169
+    // incorrect composite schedule when duration is zero
+
+    // using absolute schedule with limit 32.0, starting 2024-01-01T12:02:00Z
+    // default limit is 57.0 (DEFAULT_LIMIT_AMPERE)
+
+    load_charging_profiles_for_evse("singles/Absolute_301.json", STATION_WIDE_ID);
+
+    const DateTime start_time = ocpp::DateTime("2024-01-01T12:02:00Z");
+    const DateTime end_time = ocpp::DateTime("2024-01-01T12:02:01Z");
+    const auto expected_limit = 32.0F;
+
+    // check with end time and a corresponding duration of 1 second
+    auto result = handler->calculate_composite_schedule(start_time, end_time, STATION_WIDE_ID, ChargingRateUnitEnum::A,
+                                                        false, true);
+
+    EXPECT_EQ(result.evseId, STATION_WIDE_ID);
+    EXPECT_EQ(result.scheduleStart, start_time);
+    EXPECT_EQ(result.duration, 1);
+    EXPECT_EQ(result.chargingRateUnit, ChargingRateUnitEnum::A);
+
+    EXPECT_THAT(result.chargingSchedulePeriod, testing::ElementsAre(PeriodEquals(0, expected_limit)));
+
+    // Now with duration of 0 seconds
+    result = handler->calculate_composite_schedule(start_time, start_time, STATION_WIDE_ID, ChargingRateUnitEnum::A,
+                                                   false, true);
+
+    EXPECT_EQ(result.evseId, STATION_WIDE_ID);
+    EXPECT_EQ(result.scheduleStart, start_time);
+    EXPECT_EQ(result.duration, 0);
+    EXPECT_EQ(result.chargingRateUnit, ChargingRateUnitEnum::A);
+
+    EXPECT_THAT(result.chargingSchedulePeriod, testing::ElementsAre(PeriodEquals(0, expected_limit)));
+
+    // Now with duration of -1 second
+    result = handler->calculate_composite_schedule(end_time, start_time, STATION_WIDE_ID, ChargingRateUnitEnum::A,
+                                                   false, true);
+
+    EXPECT_EQ(result.evseId, STATION_WIDE_ID);
+    EXPECT_EQ(result.scheduleStart, start_time);
+    EXPECT_EQ(result.duration, 0);
+    EXPECT_EQ(result.chargingRateUnit, ChargingRateUnitEnum::A);
+
+    EXPECT_THAT(result.chargingSchedulePeriod, testing::ElementsAre(PeriodEquals(0, expected_limit)));
+}
+
 } // namespace ocpp::v2

lib/everest/ocpp/tests/lib/ocpp/v21/test_composite_schedule.cpp

@@ -420,3 +420,45 @@ TEST_F(CompositeScheduleTestFixtureV21, V21DifferentNumberPhases_StationWide) {
                                                                      ChargingRateUnitEnum::W, false, true);
     EXPECT_EQ(actual, expected);
 }
+
+TEST_F(CompositeScheduleTestFixtureV21, ZeroDuration) {
+    load_charging_profiles_for_evse(BASE_JSON_PATH_V21 + "/station_wide_three_phases/", STATION_WIDE_ID);
+    const DateTime start_time("2024-01-17T18:00:00.000Z");
+    const DateTime end_time("2024-01-17T18:00:01.000Z");
+
+    ChargingSchedulePeriod period1;
+    period1.startPeriod = 0;
+    period1.limit = 12420.0F;
+    period1.limit_L2 = 12430.0F;
+    period1.limit_L3 = 12440.0F;
+    period1.numberPhases = 3;
+
+    CompositeSchedule expected_0;
+    expected_0.chargingSchedulePeriod = {period1};
+    expected_0.evseId = DEFAULT_EVSE_ID;
+    expected_0.duration = 0;
+    expected_0.scheduleStart = start_time;
+    expected_0.chargingRateUnit = ChargingRateUnitEnum::W;
+
+    CompositeSchedule expected_1;
+    expected_1.chargingSchedulePeriod = {period1};
+    expected_1.evseId = DEFAULT_EVSE_ID;
+    expected_1.duration = 1;
+    expected_1.scheduleStart = start_time;
+    expected_1.chargingRateUnit = ChargingRateUnitEnum::W;
+
+    // check with end time and a corresponding duration of 1 second
+    auto actual = handler->calculate_composite_schedule(start_time, end_time, DEFAULT_EVSE_ID, ChargingRateUnitEnum::W,
+                                                        false, true);
+    EXPECT_EQ(actual, expected_1);
+
+    // Now with duration of 0 seconds
+    actual = handler->calculate_composite_schedule(start_time, start_time, DEFAULT_EVSE_ID, ChargingRateUnitEnum::W,
+                                                   false, true);
+    EXPECT_EQ(actual, expected_0);
+
+    // Now with duration of -1 second
+    actual = handler->calculate_composite_schedule(end_time, start_time, DEFAULT_EVSE_ID, ChargingRateUnitEnum::W,
+                                                   false, true);
+    EXPECT_EQ(actual, expected_0);
+}