[fenix] For https://github.com/mozilla-mobile/fenix/issues/25281 - Improve stories impressions recording.

This fixes the following two scenarios resulting in improper recordings:
- sponsored stories were recorded as shown as part of the impressions recording
for all the stories (both recommended and sponsored). Separated the two.
- sponsored stories were not recorded as shown if the user doesn't scroll.
This could happen if just toggling categories which would result in a new list
of stories to show. Will recheck after the time to settle if the composable is
shown.

app/src/main/java/org/mozilla/fenix/home/pocket/PocketStoriesComposables.kt

@@ -25,6 +25,7 @@ import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.material.Icon
 import androidx.compose.material.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -50,6 +51,7 @@ import androidx.compose.ui.tooling.preview.PreviewParameterProvider
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import kotlinx.coroutines.delay
 import mozilla.components.service.pocket.PocketStory
 import mozilla.components.service.pocket.PocketStory.PocketRecommendedStory
 import mozilla.components.service.pocket.PocketStory.PocketSponsoredStory
@@ -274,6 +276,7 @@ private fun Modifier.onShown(
     onVisible: () -> Unit,
 ): Modifier {
     val initialTime = System.currentTimeMillis()
+    var lastVisibleCoordinates: LayoutCoordinates? = null
 
     return composed {
         val context = LocalContext.current
@@ -291,14 +294,28 @@ private fun Modifier.onShown(
                 }
             }
 
-        onGloballyPositioned { coordinates ->
-            if (!wasEventReported && coordinates.isVisible(screenBounds, threshold) &&
-                System.currentTimeMillis() - initialTime > MINIMUM_TIME_TO_SETTLE_MS
-            ) {
+        // In the event this composable starts as visible but then gets pushed offscreen
+        // before MINIMUM_TIME_TO_SETTLE_MS we will not report is as being visible.
+        // In the LaunchedEffect we add support for when the composable starts as visible and then
+        // it's position isn't changed after MINIMUM_TIME_TO_SETTLE_MS so it must be reported as visible.
+        LaunchedEffect(initialTime) {
+            delay(MINIMUM_TIME_TO_SETTLE_MS.toLong())
+            if (!wasEventReported && lastVisibleCoordinates?.isVisible(screenBounds, threshold) == true) {
                 wasEventReported = true
                 onVisible()
             }
         }
+
+        onGloballyPositioned { coordinates ->
+            if (!wasEventReported && coordinates.isVisible(screenBounds, threshold)) {
+                if (System.currentTimeMillis() - initialTime > MINIMUM_TIME_TO_SETTLE_MS) {
+                    wasEventReported = true
+                    onVisible()
+                } else {
+                    lastVisibleCoordinates = coordinates
+                }
+            }
+        }
     }
 }
 

app/src/main/java/org/mozilla/fenix/home/pocket/PocketStoriesViewHolder.kt

@@ -59,7 +59,9 @@ class PocketStoriesViewHolder(
             // We should report back when a certain story is actually being displayed.
             // Cannot do it reliably so for now we'll just mass report everything as being displayed.
             stories?.let {
-                interactor.onStoriesShown(it)
+                // Only report here the impressions for recommended stories.
+                // Sponsored stories use a different API for more accurate tracking.
+                interactor.onStoriesShown(it.filterIsInstance<PocketRecommendedStory>())
             }
         }