Fixes #5341: Add UUID generation and use it on session ID and user profile identifier

domain/src/main/java/org/oppia/android/domain/oppialogger/LoggingIdentifierController.kt

@@ -42,7 +42,7 @@ class LoggingIdentifierController @Inject constructor(
   private val appSessionIdRandom by lazy { Random(appSessionRandomSeed) }
 
   private val sessionId by lazy { MutableStateFlow(computeSessionId()) }
-  private val appSessionId by lazy { MutableStateFlow(computeAppSessionId()) }
+  private val appSessionId by lazy { MutableStateFlow(generateCustomUUID().toString()) }
   private val sessionIdDataProvider by lazy {
     dataProviders.run { sessionId.convertToAutomaticDataProvider(SESSION_ID_DATA_PROVIDER_ID) }
   }
@@ -166,4 +166,30 @@ class LoggingIdentifierController @Inject constructor(
    */
   private fun Random.randomUuid(): UUID =
     UUID.nameUUIDFromBytes(ByteArray(16).also { [email protected](it) })
+
+  /**
+   * Returns a new [UUID] as [ULong] using a custom algorithm derived from Twitter's snowflake algorithm.
+   *
+   * The [UUID] is made up of;
+   * - 1 bit - This will cater for the Year 2038 problem.
+   * - 41 bits - Timestamp representation of the UTC time of generation of the UUID.
+   * - 22 bits - Random number to increase the uniqueness of the UUID generated.
+   *
+   * Return type is [ULong] to take full advantage of all the bits and avoid generating
+   * negative [UUID]s
+   */
+  fun generateCustomUUID(): ULong {
+    val SIGNED_BIT = 1L
+    val TIMESTAMP_BITS = 41
+    val RANDOM_BITS = 22
+    val MAX_RANDOM_VALUE: Long = (1L shl RANDOM_BITS) - 1
+
+    val currentTimestamp = System.currentTimeMillis()
+    val randomNumber = Random().nextLong() and MAX_RANDOM_VALUE
+
+    return (
+      (SIGNED_BIT shl (TIMESTAMP_BITS + RANDOM_BITS))
+        or (currentTimestamp shl RANDOM_BITS) or randomNumber
+      ).toULong()
+  }
 }

domain/src/main/java/org/oppia/android/domain/oppialogger/analytics/ApplicationLifecycleObserver.kt

@@ -178,7 +178,9 @@ class ApplicationLifecycleObserver @Inject constructor(
     CoroutineScope(backgroundDispatcher).launch {
       // TODO(#5341): Replace appSessionId generation to the modified Twitter snowflake algorithm.
       val appSessionId = loggingIdentifierController.getAppSessionIdFlow().value
-      featureFlagsLogger.logAllFeatureFlags(appSessionId)
+      val profileId = profileManagementController.fetchCurrentProfileUuid()
+
+      featureFlagsLogger.logAllFeatureFlags(appSessionId, profileId)
     }.invokeOnCompletion { failure ->
       if (failure != null) {
         oppiaLogger.e(

domain/src/main/java/org/oppia/android/domain/oppialogger/analytics/FeatureFlagsLogger.kt

@@ -106,7 +106,7 @@ class FeatureFlagsLogger @Inject constructor(
    *
    * @param appSessionId denotes the id of the current appInForeground session
    */
-  fun logAllFeatureFlags(appSessionId: String) {
+  fun logAllFeatureFlags(appSessionId: String, currentProfileUuid: String?) {
     val featureFlagItemList = mutableListOf<FeatureFlagItemContext>()
     for (flag in featureFlagItemMap) {
       featureFlagItemList.add(
@@ -117,6 +117,7 @@ class FeatureFlagsLogger @Inject constructor(
     // TODO(#5341): Set the UUID value for this context
     val featureFlagContext = FeatureFlagListContext.newBuilder()
       .setAppSessionId(appSessionId)
+      .setUniqueUserUuid(currentProfileUuid)
       .addAllFeatureFlags(featureFlagItemList)
       .build()
 

domain/src/main/java/org/oppia/android/domain/profile/ProfileManagementController.kt

@@ -285,6 +285,7 @@ class ProfileManagementController @Inject constructor(
         this.allowDownloadAccess = allowDownloadAccess
         this.allowInLessonQuickLanguageSwitching = allowInLessonQuickLanguageSwitching
         this.id = ProfileId.newBuilder().setInternalId(nextProfileId).build()
+        this.uuid = loggingIdentifierController.generateCustomUUID().toString()
         dateCreatedTimestampMs = oppiaClock.getCurrentTimeMs()
         this.isAdmin = isAdmin
         readingTextSize = ReadingTextSize.MEDIUM_TEXT_SIZE
@@ -918,6 +919,49 @@ class ProfileManagementController @Inject constructor(
    */
   suspend fun fetchCurrentLearnerId(): String? = getCurrentProfileId()?.let { fetchLearnerId(it) }
 
+  suspend fun fetchCurrentProfileUuid(): String {
+    val profileId = getCurrentProfileId()
+    val profileDatabase = profileDataStore.readDataAsync().await()
+
+    return if (profileDatabase.profilesMap[profileId?.internalId]?.uuid != null) {
+      profileDatabase.profilesMap[profileId!!.internalId]!!.uuid!!
+    } else {
+      if (profileId == null) return ""
+
+      val randomUuid = loggingIdentifierController.generateCustomUUID().toString()
+      updateCurrentProfileUuid(profileId, randomUuid)
+      randomUuid
+    }
+  }
+
+  /**
+   * Updates the UUID of an existing profile.
+   *
+   * @param profileId the ID corresponding to the profile being updated.
+   * @param newUuid New UUID for the profile being updated.
+   * @return a [DataProvider] that indicates the success/failure of this update operation.
+   */
+  private fun updateCurrentProfileUuid(profileId: ProfileId, newUuid: String): DataProvider<Any?> {
+    val deferred = profileDataStore.storeDataWithCustomChannelAsync(
+      updateInMemoryCache = true
+    ) {
+      val profile =
+        it.profilesMap[profileId.internalId] ?: return@storeDataWithCustomChannelAsync Pair(
+          it,
+          ProfileActionStatus.PROFILE_NOT_FOUND
+        )
+      val updatedProfile = profile.toBuilder().setUuid(newUuid).build()
+      val profileDatabaseBuilder = it.toBuilder().putProfiles(
+        profileId.internalId,
+        updatedProfile
+      )
+      Pair(profileDatabaseBuilder.build(), ProfileActionStatus.SUCCESS)
+    }
+    return dataProviders.createInMemoryDataProviderAsync(UPDATE_NAME_PROVIDER_ID) {
+      return@createInMemoryDataProviderAsync getDeferredResult(profileId, newUuid, deferred)
+    }
+  }
+
   /**
    * Returns the learner ID corresponding to the specified [profileId], or null if the specified
    * profile doesn't exist.

model/src/main/proto/profile.proto

@@ -34,6 +34,9 @@ message Profile {
   // Unique ID given to each profile.
   ProfileId id = 1;
 
+  // Unique 64-bit UUID assigned to each profile
+  string uuid = 20;
+
   // Name of the user.
   string name = 2;