Active tracing days count can be negative (EXPOSUREAPP-1844) #828 (#1029)

* Refactored method

* Normalized interval pairs.

* Perfoming additional check for from date

* Removed changes from build.gradle

* Fixed lint errors

Co-authored-by: Jakob Möller <jakob.moeller@sap.com>

Corona-Warn-App/src/main/java/de/rki/coronawarnapp/risk/TimeVariables.kt

@@ -188,22 +188,19 @@ object TimeVariables {
 
         // by default the tracing is assumed to be activated
         // if the API is reachable we set the value accordingly 
-        var enIsDisabled = false
-
-        try {
-            enIsDisabled = !InternalExposureNotificationClient.asyncIsEnabled()
+        val enIsDisabled = try {
+            !InternalExposureNotificationClient.asyncIsEnabled()
         } catch (e: ApiException) {
             e.report(ExceptionCategory.EXPOSURENOTIFICATION)
+            false
         }
 
         if (enIsDisabled) {
             val current = System.currentTimeMillis()
-            var lastTimeTracingWasNotActivated =
-                LocalData.lastNonActiveTracingTimestamp() ?: current
-
-            if (lastTimeTracingWasNotActivated < (current - getTimeRangeFromRetentionPeriod())) {
-                lastTimeTracingWasNotActivated = current - getTimeRangeFromRetentionPeriod()
-            }
+            val lastTimeTracingWasNotActivated = minOf(
+                LocalData.lastNonActiveTracingTimestamp() ?: current,
+                current - tracingActiveMS
+            )
 
             inactiveTracingIntervals.add(Pair(lastTimeTracingWasNotActivated, current))
         }

Corona-Warn-App/src/main/java/de/rki/coronawarnapp/storage/tracing/TracingIntervalRepository.kt

@@ -61,14 +61,12 @@ class TracingIntervalRepository(private val tracingIntervalDao: TracingIntervalD
     }
 
     suspend fun getIntervals(): List<Pair<Long, Long>> {
-        deleteOutdatedInterval()
-        return tracingIntervalDao.getAllIntervals().map {
-            Pair(it.from, it.to)
-        }.also {
-            Timber.d("Intervals: $it")
-        }
-    }
+        val retentionTimestamp = System.currentTimeMillis() - TimeVariables.getDefaultRetentionPeriodInMS()
+        tracingIntervalDao.deleteOutdatedIntervals(retentionTimestamp)
 
-    private suspend fun deleteOutdatedInterval() = tracingIntervalDao
-        .deleteOutdatedIntervals(System.currentTimeMillis() - TimeVariables.getDefaultRetentionPeriodInMS())
+        return tracingIntervalDao
+            .getAllIntervals()
+            .map { Pair(maxOf(it.from, retentionTimestamp), it.to) }
+            .also { Timber.d("Intervals: $it") }
+    }
 }