feat : implement gesture assistantHandler option

- closes : #5240

lawnchair/res/values/strings.xml

@@ -472,6 +472,7 @@
     <string name="gesture_handler_open_app_drawer">Open app drawer</string>
     <string name="gesture_handler_open_app_search">Open app search</string>
     <string name="gesture_handler_open_search">Open search</string>
+    <string name="gesture_handler_open_assistant">Open assistant</string>
 
     <string name="pick_app_for_gesture">Pick app</string>
 

lawnchair/src/app/lawnchair/gestures/config/GestureHandlerConfig.kt

@@ -7,6 +7,7 @@ import app.lawnchair.gestures.handlers.OpenAppDrawerGestureHandler
 import app.lawnchair.gestures.handlers.OpenAppGestureHandler
 import app.lawnchair.gestures.handlers.OpenAppSearchGestureHandler
 import app.lawnchair.gestures.handlers.OpenAppTarget
+import app.lawnchair.gestures.handlers.OpenAssistantHandler
 import app.lawnchair.gestures.handlers.OpenNotificationsHandler
 import app.lawnchair.gestures.handlers.OpenSearchGestureHandler
 import app.lawnchair.gestures.handlers.RecentsGestureHandler
@@ -61,6 +62,10 @@ sealed class GestureHandlerConfig {
     @SerialName("openSearch")
     data object OpenSearch : Simple(R.string.gesture_handler_open_search, ::OpenSearchGestureHandler)
 
+    @Serializable
+    @SerialName("openAssistant")
+    data object OpenAssistant : Simple(R.string.gesture_handler_open_assistant, ::OpenAssistantHandler)
+
     @Serializable
     @SerialName("openApp")
     data class OpenApp(val appName: String, val target: OpenAppTarget) : GestureHandlerConfig() {

lawnchair/src/app/lawnchair/gestures/config/GestureHandlerOption.kt

@@ -30,6 +30,7 @@ sealed class GestureHandlerOption(
     data object OpenAppDrawer : Simple(GestureHandlerConfig.OpenAppDrawer)
     data object OpenAppSearch : Simple(GestureHandlerConfig.OpenAppSearch)
     data object OpenSearch : Simple(GestureHandlerConfig.OpenSearch)
+    data object OpenAssistant : Simple(GestureHandlerConfig.OpenAssistant)
 
     data object OpenApp : GestureHandlerOption(
         R.string.gesture_handler_open_app_option,

lawnchair/src/app/lawnchair/gestures/handlers/OpenAssistantHandler.kt

@@ -0,0 +1,63 @@
+package app.lawnchair.gestures.handlers
+
+import android.content.ComponentName
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.provider.Settings
+import android.util.Log
+import app.lawnchair.LawnchairLauncher
+
+class OpenAssistantHandler(context: Context) : GestureHandler(context) {
+
+    override suspend fun onTrigger(launcher: LawnchairLauncher) {
+        try {
+            val component = getCurrentlySelectedDefaultAssistant(context)
+            Log.d(TAG, "Detected assistant: $component")
+
+            when {
+                component == null -> noValidAssistantFound()
+                isActivity(component) -> launchIntent(Intent(Intent.ACTION_ASSIST).setComponent(component))
+                isService(component) -> launchIntent(Intent(Intent.ACTION_VOICE_COMMAND))
+                isInstalled(component.packageName) -> launchIntent(context.packageManager.getLaunchIntentForPackage(component.packageName))
+                else -> noValidAssistantFound()
+            }
+        } catch (e: Exception) {
+            Log.e(TAG, "Error launching assistant", e)
+            noValidAssistantFound()
+        }
+    }
+
+    private fun launchIntent(intent: Intent?) {
+        intent?.apply {
+            flags = Intent.FLAG_ACTIVITY_NEW_TASK
+            runCatching { context.startActivity(this) }
+                .onFailure { Log.e(TAG, "Failed to launch intent: $intent", it) }
+        } ?: Log.e(TAG, "Intent is null, cannot launch.")
+    }
+
+    private fun noValidAssistantFound() {
+        Log.e(TAG, "No valid assistant found, opening voice input settings.")
+        launchIntent(Intent(Settings.ACTION_VOICE_INPUT_SETTINGS))
+    }
+
+    private fun getCurrentlySelectedDefaultAssistant(context: Context): ComponentName? = Settings.Secure.getString(context.contentResolver, "assistant")
+        ?.takeIf { it.isNotEmpty() }
+        ?.let(ComponentName::unflattenFromString)
+        ?: context.packageManager.resolveActivity(Intent(Intent.ACTION_ASSIST), PackageManager.MATCH_DEFAULT_ONLY)
+            ?.activityInfo?.let { ComponentName(it.packageName, it.name) }
+
+    private fun isActivity(component: ComponentName) = context.packageManager.queryIntentActivities(Intent().setComponent(component), PackageManager.MATCH_DEFAULT_ONLY).isNotEmpty()
+
+    private fun isService(component: ComponentName) = context.packageManager.getInstalledPackages(PackageManager.GET_SERVICES)
+        .any { it.packageName == component.packageName && it.services?.any { service -> service.name == component.className } == true }
+
+    private fun isInstalled(packageName: String) = runCatching {
+        context.packageManager.getPackageInfo(packageName, 0)
+        true
+    }.getOrDefault(false)
+
+    companion object {
+        private const val TAG = "OpenAssistantHandler"
+    }
+}

lawnchair/src/app/lawnchair/ui/preferences/components/GestureHandlerPreference.kt

@@ -32,6 +32,7 @@ val options = listOf(
     GestureHandlerOption.OpenAppSearch,
     GestureHandlerOption.OpenSearch,
     GestureHandlerOption.OpenApp,
+    GestureHandlerOption.OpenAssistant,
 )
 
 @Composable