818: Track favorites and filter old duplicated entries

Author: Lakoja

app/src/main/java/com/keylesspalace/tusky/components/notifications/NotificationsFragment.kt

@@ -205,10 +205,13 @@ class NotificationsFragment :
         (binding.recyclerView.itemAnimator as SimpleItemAnimator?)!!.supportsChangeAnimations =
             false
 
-        // Signal the user that a refresh has loaded new items above their current position
-        // by scrolling up slightly to disclose the new content
+
         adapter.registerAdapterDataObserver(object : RecyclerView.AdapterDataObserver() {
             override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
+                removeDuplicateOlderEntries(positionStart)
+
+                // Signal the user that a refresh has loaded new items above their current position
+                // by scrolling up slightly to disclose the new content
                 if (positionStart == 0 && adapter.itemCount != itemCount) {
                     binding.recyclerView.post {
                         binding.recyclerView.scrollBy(0, Utils.dpToPx(requireContext(), -30))
@@ -233,6 +236,7 @@ class NotificationsFragment :
                     viewModel.pagingData.collectLatest { pagingData ->
                         Log.d(TAG, "Submitting data to adapter")
                         adapter.submitData(pagingData)
+                        // TODO why is this called always _before_ anything from NotificationsPagingSource is loaded (and with what data)?
                     }
                 }
 
@@ -420,6 +424,27 @@ class NotificationsFragment :
         }
     }
 
+    private fun removeDuplicateOlderEntries(positionStart: Int) {
+        val dataList = adapter.snapshot().items
+
+        Log.w(TAG, "found elements in adapter "+dataList.size)
+
+        for (pos in dataList.size - 1 downTo  positionStart) {
+            val notificationViewData = dataList[pos]
+
+            val status = notificationViewData.statusViewData?.status
+                ?: continue
+
+            if (!viewModel.hasNewestNotificationId(notificationViewData.type, status.id, notificationViewData.id)) {
+                Log.w(TAG, "Removing old notification at "+pos+" for "+status.id)
+
+                adapter.notifyItemRemoved(pos)
+            }
+        }
+
+        Log.w(TAG, "elements after second "+ adapter.snapshot().size)
+    }
+
     override fun onCreateMenu(menu: Menu, menuInflater: MenuInflater) {
         menuInflater.inflate(R.menu.fragment_notifications, menu)
         menu.findItem(R.id.action_refresh)?.apply {

app/src/main/java/com/keylesspalace/tusky/components/notifications/NotificationsViewModel.kt

@@ -24,6 +24,7 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import androidx.paging.PagingData
 import androidx.paging.cachedIn
+import androidx.paging.filter
 import androidx.paging.map
 import com.keylesspalace.tusky.R
 import com.keylesspalace.tusky.appstore.BlockEvent
@@ -482,13 +483,28 @@ class NotificationsViewModel @Inject constructor(
         )
     }
 
+    // Status id -> (highest) Notification id
+    val seenFavorites = HashMap<String, String>()
+
     private fun getNotifications(
         filters: Set<Notification.Type>,
         initialKey: String? = null
     ): Flow<PagingData<NotificationViewData>> {
         return repository.getNotificationsStream(filter = filters, initialKey = initialKey)
             .map { pagingData ->
-                pagingData.map { notification ->
+                pagingData.filter { notification ->
+                    val status = notification.status
+                        ?: return@filter true
+
+                    return@filter if (hasNewestNotificationId(notification.type, status.id, notification.id)) {
+                        seenFavorites[status.id] = notification.id // TODO move to hasNewestNotificationId?
+
+                        true
+                    } else {
+                        false
+                    }
+                }
+               .map { notification ->
                     notification.toViewData(
                         isShowingContent = statusDisplayOptions.value.showSensitiveMedia ||
                             !(notification.status?.actionableStatus?.sensitive ?: false),
@@ -499,6 +515,29 @@ class NotificationsViewModel @Inject constructor(
             }
     }
 
+    fun hasNewestNotificationId(type: Notification.Type, statusId: String, notificationId: String): Boolean {
+        if (type != Notification.Type.FAVOURITE) {
+            return true
+        }
+
+        val highestNotificationId = seenFavorites[statusId]
+
+        return highestNotificationId == null || isEqualOrNewer(notificationId, highestNotificationId)
+    }
+
+    /**
+     * NOTE this currently assumes that the ids are integers. Can that change? If it does all notifications are unequal.
+     */
+    fun isEqualOrNewer(thisId: String, idToCompare: String): Boolean {
+        try {
+            return thisId.toInt() >= idToCompare.toInt()
+        } catch (exc: NumberFormatException) {
+            Log.e(TAG, "Cannot compare ids; not numbers: "+thisId+"/"+idToCompare)
+
+            return false
+        }
+    }
+
     /**
      * @return Flow of relevant preferences that change the UI
      */