[fenix] For https://github.com/mozilla-mobile/fenix/issues/28111: Filter out topic specific search engines from default list

Since topic specific search engines, like amazon, ebay, etc...
will only show results from those specific websites, they will be filtered
out of the default search engines list.

app/src/androidTest/java/org/mozilla/fenix/ui/SettingsSearchTest.kt

@@ -376,6 +376,7 @@ class SettingsSearchTest {
         }
     }
 
+    @Ignore("Test failure caused by: https://bugzilla.mozilla.org/show_bug.cgi?id=1807298")
     // Expected for en-us defaults
     @Test
     fun deleteAllSearchEnginesTest() {

app/src/main/java/org/mozilla/fenix/FenixApplication.kt

@@ -28,6 +28,8 @@ import kotlinx.coroutines.launch
 import mozilla.appservices.Megazord
 import mozilla.components.browser.state.action.SystemAction
 import mozilla.components.browser.state.selector.selectedTab
+import mozilla.components.browser.state.state.searchEngines
+import mozilla.components.browser.state.state.selectedOrDefaultSearchEngine
 import mozilla.components.browser.state.store.BrowserStore
 import mozilla.components.browser.storage.sync.GlobalPlacesDependencyProvider
 import mozilla.components.concept.base.crash.Breadcrumb
@@ -245,6 +247,7 @@ open class FenixApplication : LocaleAwareApplication(), Provider {
         setupLeakCanary()
         startMetricsIfEnabled()
         setupPush()
+        migrateTopicSpecificSearchEngines()
 
         visibilityLifecycleCallback = VisibilityLifecycleCallback(getSystemService())
         registerActivityLifecycleCallbacks(visibilityLifecycleCallback)
@@ -553,6 +556,25 @@ open class FenixApplication : LocaleAwareApplication(), Provider {
         }
     }
 
+    /**
+     * If unified search is enabled try to migrate the topic specific engine to the
+     * first general or custom search engine available.
+     */
+    @Suppress("NestedBlockDepth")
+    private fun migrateTopicSpecificSearchEngines() {
+        if (settings().showUnifiedSearchFeature) {
+            components.core.store.state.search.selectedOrDefaultSearchEngine.let { currentSearchEngine ->
+                if (currentSearchEngine?.isGeneral == false) {
+                    components.core.store.state.search.searchEngines.firstOrNull() { nextSearchEngine ->
+                        nextSearchEngine.isGeneral
+                    }?.let {
+                        components.useCases.searchUseCases.selectSearchEngine(it)
+                    }
+                }
+            }
+        }
+    }
+
     @OptIn(DelicateCoroutinesApi::class) // GlobalScope usage
     private fun warmBrowsersCache() {
         // We avoid blocking the main thread for BrowsersCache on startup by loading it on

app/src/main/java/org/mozilla/fenix/settings/search/AddSearchEngineFragment.kt

@@ -182,6 +182,7 @@ class AddSearchEngineFragment :
                         name,
                         searchString.toSearchUrl(),
                         requireComponents.core.icons.loadIcon(IconRequest(searchString)).await().bitmap,
+                        isGeneral = true,
                     )
 
                     requireComponents.useCases.searchUseCases.addSearchEngine(searchEngine)

app/src/main/java/org/mozilla/fenix/settings/search/RadioSearchEngineListPreference.kt

@@ -20,7 +20,6 @@ import androidx.preference.Preference
 import androidx.preference.PreferenceViewHolder
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.MainScope
-import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.launch
 import mozilla.components.browser.state.search.SearchEngine
@@ -35,6 +34,7 @@ import org.mozilla.fenix.R
 import org.mozilla.fenix.databinding.SearchEngineRadioButtonBinding
 import org.mozilla.fenix.ext.components
 import org.mozilla.fenix.ext.getRootView
+import org.mozilla.fenix.ext.settings
 import org.mozilla.fenix.utils.allowUndo
 
 class RadioSearchEngineListPreference @JvmOverloads constructor(
@@ -76,14 +76,23 @@ class RadioSearchEngineListPreference @JvmOverloads constructor(
             ViewGroup.LayoutParams.WRAP_CONTENT,
         )
 
+        val isLastGeneralOrCustomSearchEngine = state.searchEngines.filter {
+            it.isGeneral
+        }.size == 1
         state.searchEngines.filter { engine ->
             engine.type != SearchEngine.Type.APPLICATION
         }.forEach { engine ->
+            val isLastSearchEngineAvailable =
+                state.searchEngines.count { it.type != SearchEngine.Type.APPLICATION } > 1
             val searchEngineView = makeButtonFromSearchEngine(
                 engine = engine,
                 layoutInflater = layoutInflater,
                 res = context.resources,
-                allowDeletion = state.searchEngines.count { it.type != SearchEngine.Type.APPLICATION } > 1,
+                allowDeletion = if (context.settings().showUnifiedSearchFeature) {
+                    isLastSearchEngineAvailable && !(engine.isGeneral && isLastGeneralOrCustomSearchEngine)
+                } else {
+                    isLastSearchEngineAvailable
+                },
                 isSelected = engine == state.selectedOrDefaultSearchEngine,
             )
 
@@ -104,7 +113,12 @@ class RadioSearchEngineListPreference @JvmOverloads constructor(
 
         val binding = SearchEngineRadioButtonBinding.bind(wrapper)
 
-        wrapper.setOnClickListener { binding.radioButton.isChecked = true }
+        if (context.settings().showUnifiedSearchFeature && !engine.isGeneral) {
+            binding.radioButton.isEnabled = false
+            wrapper.isEnabled = false
+        } else {
+            wrapper.setOnClickListener { binding.radioButton.isChecked = true }
+        }
         binding.radioButton.tag = engine.id
         binding.radioButton.isChecked = isSelected
         binding.radioButton.setOnCheckedChangeListener(this)
@@ -155,6 +169,19 @@ class RadioSearchEngineListPreference @JvmOverloads constructor(
         context: Context,
         engine: SearchEngine,
     ) {
+        val selectedOrDefaultSearchEngine = context.components.core.store.state.search.selectedOrDefaultSearchEngine
+        if (selectedOrDefaultSearchEngine == engine) {
+            val nextSearchEngine = if (context.settings().showUnifiedSearchFeature) {
+                context.components.core.store.state.search.searchEngines.first {
+                    it.id != engine.id && (it.isGeneral || it.type == SearchEngine.Type.CUSTOM)
+                }
+            } else {
+                context.components.core.store.state.search.searchEngines.first {
+                    it.id != engine.id
+                }
+            }
+            context.components.useCases.searchUseCases.selectSearchEngine(nextSearchEngine)
+        }
         context.components.useCases.searchUseCases.removeSearchEngine(engine)
 
         MainScope().allowUndo(
@@ -164,6 +191,9 @@ class RadioSearchEngineListPreference @JvmOverloads constructor(
             undoActionTitle = context.getString(R.string.snackbar_deleted_undo),
             onCancel = {
                 context.components.useCases.searchUseCases.addSearchEngine(engine)
+                if (selectedOrDefaultSearchEngine == engine) {
+                    context.components.useCases.searchUseCases.selectSearchEngine(engine)
+                }
             },
             operation = {},
         )