Fix VU activity date extraction from downloadTime

src/main/java/at/procon/eventhub/tachographfilesession/service/VehicleUnitXmlExtractionService.java

@@ -226,39 +226,34 @@ public class VehicleUnitXmlExtractionService {
             VehicleContext vehicleContext,
             List<ExtractionWarning> warnings
     ) {
-        NodeList dayRecords = nodes(document, "/VehicleUnit/Activities/vuActivityDailyData");
+        NodeList activitySections = nodes(document, "/VehicleUnit/Activities");
-        if (dayRecords.getLength() == 0) {
+        if (activitySections.getLength() == 0) {
             return List.of();
         }
 
-        LocalDate startDate = vehicleContext.defaultActivityStartDate();
-        if (startDate == null) {
-            warnings.add(new ExtractionWarning(
-                    "VU_ACTIVITY_DATE_INFERENCE_FAILED",
-                    "Vehicle-unit activity daily data is present but no base date could be inferred from the VU downloadable period.",
-                    "/VehicleUnit/Activities/vuActivityDailyData"
-            ));
-            return List.of();
-        }
-
-        LocalDate maxDate = vehicleContext.defaultActivityEndDate();
-        if (maxDate != null) {
-            LocalDate inferredEndDate = startDate.plusDays(dayRecords.getLength() - 1L);
-            if (inferredEndDate.isAfter(maxDate)) {
-                warnings.add(new ExtractionWarning(
-                        "VU_ACTIVITY_DATE_INFERENCE_RANGE",
-                        "Vehicle-unit activity daily records exceed the VU downloadable-period range when mapped by sequence order.",
-                        "/VehicleUnit/Activities/vuActivityDailyData"
-                ));
-            }
-        }
-
         List<ExtractedCardActivityInterval> intervals = new ArrayList<>();
         int intervalNo = 0;
+        int fallbackDayIndex = 0;
+        for (int activityIndex = 0; activityIndex < activitySections.getLength(); activityIndex++) {
+            Element activities = (Element) activitySections.item(activityIndex);
+            NodeList dayRecords = nodes(activities, "vuActivityDailyData");
             for (int dayIndex = 0; dayIndex < dayRecords.getLength(); dayIndex++) {
                 Element dayRecord = (Element) dayRecords.item(dayIndex);
-            LocalDate date = startDate.plusDays(dayIndex);
+                String dayPath = dayRecords.getLength() == 1
-            String dayPath = "/VehicleUnit/Activities[" + (dayIndex + 1) + "]/vuActivityDailyData";
+                        ? "/VehicleUnit/Activities[" + (activityIndex + 1) + "]/vuActivityDailyData"
+                        : "/VehicleUnit/Activities[" + (activityIndex + 1) + "]/vuActivityDailyData[" + (dayIndex + 1) + "]";
+                LocalDate date = resolveActivityDate(
+                        activities,
+                        vehicleContext,
+                        activityIndex,
+                        fallbackDayIndex + dayIndex,
+                        dayPath,
+                        warnings
+                );
+                if (date == null) {
+                    continue;
+                }
+
                 NodeList changes = nodes(dayRecord, "activityChangeInfos");
                 List<ActivityChange> parsedChanges = new ArrayList<>();
                 for (int changeIndex = 0; changeIndex < changes.getLength(); changeIndex++) {
@@ -305,11 +300,48 @@ public class VehicleUnitXmlExtractionService {
                     ));
                 }
             }
+            fallbackDayIndex += dayRecords.getLength();
+        }
 
         intervals.sort(Comparator.comparing(ExtractedCardActivityInterval::from));
         return intervals;
     }
 
+    private LocalDate resolveActivityDate(
+            Element activities,
+            VehicleContext vehicleContext,
+            int activityIndex,
+            int fallbackDayIndex,
+            String dayPath,
+            List<ExtractionWarning> warnings
+    ) {
+        OffsetDateTime downloadTime = offsetDateTime(text(activities, "downloadTime"));
+        if (downloadTime != null) {
+            return downloadTime.withOffsetSameInstant(ZoneOffset.UTC).toLocalDate();
+        }
+
+        LocalDate fallbackDate = vehicleContext.defaultActivityStartDate();
+        if (fallbackDate == null) {
+            warnings.add(new ExtractionWarning(
+                    "VU_ACTIVITY_DATE_INFERENCE_FAILED",
+                    "Vehicle-unit activity daily data is present but neither Activities/downloadTime nor the VU downloadable period can provide its date.",
+                    dayPath
+            ));
+            return null;
+        }
+
+        LocalDate resolvedDate = fallbackDate.plusDays(fallbackDayIndex);
+        LocalDate maxDate = vehicleContext.defaultActivityEndDate();
+        if (maxDate != null && resolvedDate.isAfter(maxDate)) {
+            warnings.add(new ExtractionWarning(
+                    "VU_ACTIVITY_DATE_INFERENCE_RANGE",
+                    "Vehicle-unit activity daily records exceed the VU downloadable-period range when mapped by sequence order.",
+                    "/VehicleUnit/Activities[" + (activityIndex + 1) + "]"
+            ));
+        }
+        return resolvedDate;
+    }
+
     private void assignActivityCoverage(
             List<ExtractedCardActivityInterval> vuActivityIntervals,
             List<VuCardIwInterval> vuCardIwIntervals,

src/test/java/at/procon/eventhub/tachographfilesession/service/VehicleUnitXmlExtractionServiceTest.java

@@ -111,6 +111,35 @@ class VehicleUnitXmlExtractionServiceTest {
         assertThat(secondDriver.cardActivityIntervals().get(0).from().toString()).isEqualTo("2026-04-02T07:30Z");
     }
 
+    @Test
+    void usesActivitiesDownloadTimeAsVuActivityRecordDate() throws Exception {
+        TachographFileSession session = service.extract(
+                new TachographXmlParser.ParsedTachographXml(document(VehicleUnitXmlSamples.vehicleUnitXmlWithActivityDownloadTime()), "VehicleUnit"),
+                new TachographFileSessionMetadata(
+                        "default",
+                        "legalrequirements-vehicleunit",
+                        "sample-vu",
+                        "sample-vu.ddd",
+                        "abc",
+                        10,
+                        "42",
+                        "def",
+                        false,
+                        null
+                ),
+                Instant.now(),
+                Instant.now().plus(4, ChronoUnit.HOURS)
+        );
+
+        DriverExtractionSession driver = session.driversByKey().get("12:12345678901200");
+        assertThat(driver).isNotNull();
+        assertThat(driver.cardActivityIntervals()).hasSize(2);
+        assertThat(driver.cardActivityIntervals().get(0).from()).isEqualTo(OffsetDateTime.parse("2026-05-25T08:00:00Z"));
+        assertThat(driver.cardActivityIntervals().get(1).from()).isEqualTo(OffsetDateTime.parse("2026-05-25T09:00:00Z"));
+        assertThat(driver.cardActivityIntervals().get(1).to()).isEqualTo(OffsetDateTime.parse("2026-05-26T00:00:00Z"));
+        assertThat(session.warnings()).isEmpty();
+    }
+
     @Test
     void keepsOpenVuCardUsageRecordWithoutClosingItAtDownloadPeriodEnd() throws Exception {
         TachographFileSession session = service.extract(

src/test/java/at/procon/eventhub/tachographfilesession/service/VehicleUnitXmlSamples.java

@@ -254,4 +254,64 @@ final class VehicleUnitXmlSamples {
                 .replace("<timeOfChange>11:00:00Z</timeOfChange>", "<timeOfChange>11:00:00</timeOfChange>")
                 .replace("<timeOfChange>07:30:00Z</timeOfChange>", "<timeOfChange>07:30:00</timeOfChange>");
     }
+
+    static String vehicleUnitXmlWithActivityDownloadTime() {
+        return """
+                <VehicleUnit>
+                  <Overview>
+                    <vehicleIdentificationNumber>VINVU123456789012</vehicleIdentificationNumber>
+                    <vehicleRegistrationIdentification>
+                      <vehicleRegistrationNation>12</vehicleRegistrationNation>
+                      <vehicleRegistrationNumber><vehicleRegNumber>W-1000V</vehicleRegNumber></vehicleRegistrationNumber>
+                    </vehicleRegistrationIdentification>
+                    <vuDownloadablePeriod>
+                      <minDownloadableTime>2026-05-20T00:00:00Z</minDownloadableTime>
+                      <maxDownloadableTime>2026-05-20T23:59:59Z</maxDownloadableTime>
+                    </vuDownloadablePeriod>
+                  </Overview>
+                  <Activities Generation="3">
+                    <downloadTime>2026-05-25T23:59:59Z</downloadTime>
+                    <odometerValueMidnight>3756</odometerValueMidnight>
+                    <vuCardIWData>
+                      <vuCardIWRecords>
+                        <cardHolderName>
+                          <holderSurname><name>Muster</name></holderSurname>
+                          <holderFirstNames><name>Max</name></holderFirstNames>
+                        </cardHolderName>
+                        <fullCardNumber>
+                          <cardType>DRIVER_CARD</cardType>
+                          <cardIssuingMemberState>12</cardIssuingMemberState>
+                          <cardNumber>
+                            <driverIdentification>123456789012</driverIdentification>
+                            <cardReplacementIndex>0</cardReplacementIndex>
+                            <cardRenewalIndex>0</cardRenewalIndex>
+                          </cardNumber>
+                          <generation>3</generation>
+                        </fullCardNumber>
+                        <cardInsertionTime>2026-05-25T08:00:00Z</cardInsertionTime>
+                        <vehicleOdometerValueAtInsertion>3700</vehicleOdometerValueAtInsertion>
+                        <cardSlotNumber>DRIVER</cardSlotNumber>
+                      </vuCardIWRecords>
+                    </vuCardIWData>
+                    <vuActivityDailyData>
+                      <noOfActivityChanges>2</noOfActivityChanges>
+                      <activityChangeInfos>
+                        <slot>DRIVER</slot>
+                        <drivingStatus>SINGLE</drivingStatus>
+                        <cardStatus>INSERTED</cardStatus>
+                        <activity>WORK</activity>
+                        <timeOfChange>08:00:00Z</timeOfChange>
+                      </activityChangeInfos>
+                      <activityChangeInfos>
+                        <slot>DRIVER</slot>
+                        <drivingStatus>SINGLE</drivingStatus>
+                        <cardStatus>INSERTED</cardStatus>
+                        <activity>DRIVING</activity>
+                        <timeOfChange>09:00:00Z</timeOfChange>
+                      </activityChangeInfos>
+                    </vuActivityDailyData>
+                  </Activities>
+                </VehicleUnit>
+                """;
+    }
 }