Fix: Undo delete snackbar in the browser (#5908)

Task/Issue URL:
https://app.asana.com/1/137249556945/project/1202552961248957/task/1209975829243855?focus=true

### Description

This PR fixes the mechanism to display the undo delete snackbar in the
browser screen after all tabs are deleted in the tab switcher, when the
snackbar would not show up correctly.

The PR also fixes the position of the snackbar so that it's shown above
the omnibar if it's set to the bottom position.

### Steps to test this PR

- [x] Have 3 tabs and Omnibar set to bottom of the screen
- [x] Close a tab that is not selected
- [x] Switch to the last tab that is not selected while the snackbar is
showing
- [x] Verify no snackbar is displayed in the browser screen
- [x] Go back to the tab switcher
- [x] Close one of the tabs, then immediately close the last tab
- [x] Verify the undo snackbar is displayed for the last tab closed
- [x] Verify the snackbar is displayed above the bottom address bar

### UI changes

<image
src="https://github.com/user-attachments/assets/7816d82f-004e-4534-ba01-8c91e386d13b"
width="300" />

Author: 0nko

app/src/main/java/com/duckduckgo/app/browser/BrowserActivity.kt

@@ -35,9 +35,7 @@ import androidx.activity.result.contract.ActivityResultContracts
 import androidx.annotation.VisibleForTesting
 import androidx.core.view.isVisible
 import androidx.core.view.postDelayed
-import androidx.lifecycle.Lifecycle.State.RESUMED
 import androidx.lifecycle.Lifecycle.State.STARTED
-import androidx.lifecycle.flowWithLifecycle
 import androidx.lifecycle.lifecycleScope
 import androidx.lifecycle.repeatOnLifecycle
 import androidx.viewpager2.widget.MarginPageTransformer
@@ -102,7 +100,7 @@ import com.duckduckgo.site.permissions.impl.ui.SitePermissionScreenNoParams
 import javax.inject.Inject
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
-import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.runBlocking
@@ -339,12 +337,6 @@ open class BrowserActivity : DuckDuckGoActivity() {
                 }
             }
         }
-
-        if (tabManagerFeatureFlags.multiSelection().isEnabled()) {
-            lifecycleScope.launch {
-                viewModel.deletableTabsFlow.flowWithLifecycle(lifecycle, RESUMED).collect()
-            }
-        }
     }
 
     override fun onStop() {
@@ -653,20 +645,33 @@ open class BrowserActivity : DuckDuckGoActivity() {
     }
 
     private fun showTabsDeletedSnackbar(tabIds: List<String>) {
-        TabSwitcherSnackbar(
-            anchorView = binding.fragmentContainer,
-            message = resources.getQuantityString(R.plurals.tabSwitcherCloseTabsSnackbar, tabIds.size, tabIds.size),
-            action = getString(R.string.tabClosedUndo),
-            showAction = true,
-            onAction = { viewModel.undoDeletableTabs(tabIds) },
-            onDismiss = { viewModel.purgeDeletableTabs() },
-        ).show()
+        lifecycleScope.launch {
+            // allow the tab fragment to initialize for the snackbar
+            delay(500)
+
+            val anchorView = when (settingsDataStore.omnibarPosition) {
+                TOP -> binding.fragmentContainer
+                BOTTOM -> currentTab?.omnibar?.newOmnibar ?: binding.fragmentContainer
+            }
+            TabSwitcherSnackbar(
+                anchorView = anchorView,
+                message = resources.getQuantityString(R.plurals.tabSwitcherCloseTabsSnackbar, tabIds.size, tabIds.size),
+                action = getString(R.string.tabClosedUndo),
+                showAction = true,
+                onAction = { viewModel.undoDeletableTabs(tabIds) },
+                onDismiss = { viewModel.purgeDeletableTabs() },
+            ).show()
+        }
     }
 
     private fun launchNewSearch(intent: Intent): Boolean {
         return intent.getBooleanExtra(NEW_SEARCH_EXTRA, false)
     }
 
+    fun onTabsDeletedInTabSwitcher(tabIds: List<String>) {
+        viewModel.onTabsDeletedInTabSwitcher(tabIds)
+    }
+
     fun clearTabsAndRecreate() {
         tabPagerAdapter.clearFragments()
         recreate()

app/src/main/java/com/duckduckgo/app/browser/BrowserTabFragment.kt

@@ -582,7 +582,7 @@ class BrowserTabFragment :
 
     private val binding: FragmentBrowserTabBinding by viewBinding()
 
-    private lateinit var omnibar: Omnibar
+    lateinit var omnibar: Omnibar
 
     private lateinit var webViewContainer: FrameLayout
 
@@ -617,6 +617,20 @@ class BrowserTabFragment :
 
     private var webView: DuckDuckGoWebView? = null
 
+    private val tabSwitcherActivityResult = registerForActivityResult(StartActivityForResult()) { result ->
+        if (result.resultCode == RESULT_OK) {
+            // Handle any result data if needed
+            result.data?.let { intent ->
+                intent.extras?.let { extras ->
+                    val deletedTabIds = extras.getStringArrayList(TabSwitcherActivity.EXTRA_KEY_DELETED_TAB_IDS)
+                    if (!deletedTabIds.isNullOrEmpty()) {
+                        (activity as? BrowserActivity?)?.onTabsDeletedInTabSwitcher(deletedTabIds)
+                    }
+                }
+            }
+        }
+    }
+
     private val activityResultHandlerEmailProtectionInContextSignup = registerForActivityResult(StartActivityForResult()) { result: ActivityResult ->
         when (result.resultCode) {
             EmailProtectionInContextSignUpScreenResult.SUCCESS -> {
@@ -1232,7 +1246,8 @@ class BrowserTabFragment :
 
     private fun launchTabSwitcher() {
         val activity = activity ?: return
-        startActivity(TabSwitcherActivity.intent(activity, tabId))
+        val intent = TabSwitcherActivity.intent(activity, tabId)
+        tabSwitcherActivityResult.launch(intent)
     }
 
     override fun onResume() {

app/src/main/java/com/duckduckgo/app/browser/BrowserViewModel.kt

@@ -67,20 +67,15 @@ import com.duckduckgo.di.scopes.AppScope
 import com.duckduckgo.feature.toggles.api.Toggle
 import javax.inject.Inject
 import kotlin.coroutines.CoroutineContext
-import kotlin.time.Duration.Companion.milliseconds
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.flow.conflate
 import kotlinx.coroutines.flow.debounce
 import kotlinx.coroutines.flow.distinctUntilChanged
-import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.filterNot
 import kotlinx.coroutines.flow.filterNotNull
-import kotlinx.coroutines.flow.firstOrNull
 import kotlinx.coroutines.flow.map
-import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
 import timber.log.Timber
 
@@ -153,14 +148,6 @@ class BrowserViewModel @Inject constructor(
         tabs.indexOf(selectedTab)
     }.filterNot { it == -1 }
 
-    val deletableTabsFlow = tabRepository.flowDeletableTabs
-        .map { tabs -> tabs.map { tab -> tab.tabId } }
-        .filter { it.isNotEmpty() }
-        .distinctUntilChanged()
-        .debounce(100.milliseconds)
-        .conflate()
-        .onEach { onDeletableTabsChanged(it) }
-
     private var dataClearingObserver = Observer<ApplicationClearDataState> { state ->
         when (state) {
             ApplicationClearDataState.INITIALIZING -> {
@@ -453,8 +440,8 @@ class BrowserViewModel @Inject constructor(
         }
     }
 
-    private fun onDeletableTabsChanged(deletableTabs: List<String>) {
-        command.value = ShowUndoDeleteTabsMessage(deletableTabs)
+    fun onTabsDeletedInTabSwitcher(tabIds: List<String>) {
+        command.value = ShowUndoDeleteTabsMessage(tabIds)
     }
 }
 

app/src/main/java/com/duckduckgo/app/browser/omnibar/Omnibar.kt

@@ -183,7 +183,7 @@ class Omnibar(
         ) : ViewMode()
     }
 
-    private val newOmnibar: OmnibarLayout by lazy {
+    val newOmnibar: OmnibarLayout by lazy {
         when (omnibarPosition) {
             OmnibarPosition.TOP -> {
                 when (omnibarType) {

app/src/main/java/com/duckduckgo/app/tabs/ui/TabSwitcherActivity.kt

@@ -63,6 +63,7 @@ import com.duckduckgo.app.tabs.ui.TabSwitcherViewModel.Command
 import com.duckduckgo.app.tabs.ui.TabSwitcherViewModel.Command.BookmarkTabsRequest
 import com.duckduckgo.app.tabs.ui.TabSwitcherViewModel.Command.Close
 import com.duckduckgo.app.tabs.ui.TabSwitcherViewModel.Command.CloseAllTabsRequest
+import com.duckduckgo.app.tabs.ui.TabSwitcherViewModel.Command.CloseAndShowUndoMessage
 import com.duckduckgo.app.tabs.ui.TabSwitcherViewModel.Command.CloseTabsRequest
 import com.duckduckgo.app.tabs.ui.TabSwitcherViewModel.Command.DismissAnimatedTileDismissalDialog
 import com.duckduckgo.app.tabs.ui.TabSwitcherViewModel.Command.ShareLink
@@ -89,6 +90,7 @@ import com.duckduckgo.common.utils.DispatcherProvider
 import com.duckduckgo.di.scopes.ActivityScope
 import com.duckduckgo.duckchat.api.DuckChat
 import com.google.android.material.floatingactionbutton.ExtendedFloatingActionButton
+import java.util.ArrayList
 import javax.inject.Inject
 import kotlin.coroutines.CoroutineContext
 import kotlin.math.max
@@ -334,15 +336,15 @@ class TabSwitcherActivity : DuckDuckGoActivity(), TabSwitcherListener, Coroutine
         )
     }
 
-    private fun updateToolbarTitle(mode: Mode, tabCount: Int) {
+    private fun updateToolbarTitle(mode: Mode) {
         toolbar.title = if (mode is Selection) {
             if (mode.selectedTabs.isEmpty()) {
                 getString(R.string.selectTabsMenuItem)
             } else {
                 getString(R.string.tabSelectionTitle, mode.selectedTabs.size)
             }
         } else {
-            resources.getQuantityString(R.plurals.tabSwitcherTitle, tabCount, tabCount)
+            getString(R.string.tabActivityTitle)
         }
     }
 
@@ -382,16 +384,16 @@ class TabSwitcherActivity : DuckDuckGoActivity(), TabSwitcherListener, Coroutine
             lifecycleScope.launch {
                 viewModel.selectionViewState.flowWithLifecycle(lifecycle).collectLatest {
                     tabsRecycler.invalidateItemDecorations()
-                    tabsAdapter.updateData(it.tabItems)
+                    tabsAdapter.updateData(it.tabSwitcherItems)
 
-                    updateToolbarTitle(it.mode, it.tabItems.size)
+                    updateToolbarTitle(it.mode)
                     updateTabGridItemDecorator()
 
                     tabTouchHelper.mode = it.mode
 
                     invalidateOptionsMenu()
 
-                    if (firstTimeLoadingTabsList && it.tabItems.isNotEmpty()) {
+                    if (firstTimeLoadingTabsList && it.tabs.isNotEmpty()) {
                         firstTimeLoadingTabsList = false
                         scrollToActiveTab()
                     }
@@ -404,7 +406,7 @@ class TabSwitcherActivity : DuckDuckGoActivity(), TabSwitcherListener, Coroutine
                 }
             }
 
-            viewModel.tabItemsLiveData.observe(this) { tabSwitcherItems ->
+            viewModel.tabSwitcherItemsLiveData.observe(this) { tabSwitcherItems ->
                 tabsAdapter.updateData(tabSwitcherItems)
 
                 val noTabSelected = tabSwitcherItems.none { (it as? NormalTab)?.isActive == true }
@@ -548,8 +550,17 @@ class TabSwitcherActivity : DuckDuckGoActivity(), TabSwitcherListener, Coroutine
 
     private fun processCommand(command: Command) {
         when (command) {
-            is Close -> {
-                skipTabPurge = command.skipTabPurge
+            Close -> {
+                finishAfterTransition()
+            }
+            is CloseAndShowUndoMessage -> {
+                skipTabPurge = true
+                setResult(
+                    RESULT_OK,
+                    Intent().apply {
+                        putStringArrayListExtra(EXTRA_KEY_DELETED_TAB_IDS, ArrayList(command.deletedTabIds))
+                    },
+                )
                 finishAfterTransition()
             }
             is CloseAllTabsRequest -> {
@@ -711,9 +722,9 @@ class TabSwitcherActivity : DuckDuckGoActivity(), TabSwitcherListener, Coroutine
 
     override fun onTabMoved(from: Int, to: Int) {
         if (tabSwitcherAnimationFeature.self().isEnabled()) {
-            val isTrackerAnimationInfoPanelVisible = viewModel.tabItems.firstOrNull() is TrackerAnimationInfoPanel
+            val isTrackerAnimationInfoPanelVisible = viewModel.tabSwitcherItems.firstOrNull() is TrackerAnimationInfoPanel
             val canSwapFromIndex = if (isTrackerAnimationInfoPanelVisible) 1 else 0
-            val tabSwitcherItemCount = viewModel.tabItems.size
+            val tabSwitcherItemCount = viewModel.tabSwitcherItems.size
 
             val canSwap = from in canSwapFromIndex..<tabSwitcherItemCount && to in canSwapFromIndex..<tabSwitcherItemCount
             if (canSwap) {
@@ -722,7 +733,7 @@ class TabSwitcherActivity : DuckDuckGoActivity(), TabSwitcherListener, Coroutine
                 viewModel.onTabMoved(from - canSwapFromIndex, to - canSwapFromIndex)
             }
         } else {
-            val tabCount = viewModel.tabItems.size
+            val tabCount = viewModel.tabSwitcherItems.size
             val canSwap = from in 0..< tabCount && to in 0..< tabCount
             if (canSwap) {
                 tabsAdapter.onTabMoved(from, to)
@@ -837,7 +848,7 @@ class TabSwitcherActivity : DuckDuckGoActivity(), TabSwitcherListener, Coroutine
     }
 
     private fun removeObservers() {
-        viewModel.tabItemsLiveData.removeObservers(this)
+        viewModel.tabSwitcherItemsLiveData.removeObservers(this)
         viewModel.deletableTabs.removeObservers(this)
     }
 
@@ -964,6 +975,7 @@ class TabSwitcherActivity : DuckDuckGoActivity(), TabSwitcherListener, Coroutine
         }
 
         const val EXTRA_KEY_SELECTED_TAB = "selected"
+        const val EXTRA_KEY_DELETED_TAB_IDS = "deletedTabIds"
 
         private const val TAB_GRID_COLUMN_WIDTH_DP = 180
         private const val TAB_GRID_MAX_COLUMN_COUNT = 4