Request notification permission for geofence alerts

android/app/src/main/kotlin/ru/akokos/ignis_app/MainActivity.kt

@@ -5,6 +5,7 @@ import android.content.Intent
 import android.content.pm.PackageManager
 import android.os.Build
 import android.provider.Settings
+import androidx.core.app.ActivityCompat
 import androidx.core.app.NotificationManagerCompat
 import androidx.core.content.ContextCompat
 import io.flutter.embedding.engine.FlutterEngine
@@ -12,6 +13,8 @@ import io.flutter.embedding.android.FlutterActivity
 import io.flutter.plugin.common.MethodChannel
 
 class MainActivity : FlutterActivity() {
+    private var pendingNotificationPermissionResult: MethodChannel.Result? = null
+
     override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
         super.configureFlutterEngine(flutterEngine)
 
@@ -67,9 +70,10 @@ class MainActivity : FlutterActivity() {
                     }
                 }
                 "getNotificationPermissionStatus" -> {
-                    result.success(
-                        if (isNotificationPermissionEnabled()) "enabled" else "disabled",
-                    )
+                    result.success(getNotificationPermissionStatusValue())
+                }
+                "requestNotificationPermission" -> {
+                    requestNotificationPermission(result)
                 }
                 "openNotificationSettings" -> {
                     val intent =
@@ -85,6 +89,70 @@ class MainActivity : FlutterActivity() {
         }
     }
 
+    override fun onRequestPermissionsResult(
+        requestCode: Int,
+        permissions: Array<out String>,
+        grantResults: IntArray,
+    ) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+
+        if (requestCode != notificationPermissionRequestCode) {
+            return
+        }
+
+        pendingNotificationPermissionResult?.success(getNotificationPermissionStatusValue())
+        pendingNotificationPermissionResult = null
+    }
+
+    private fun requestNotificationPermission(result: MethodChannel.Result) {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU) {
+            result.success(getNotificationPermissionStatusValue())
+            return
+        }
+
+        if (pendingNotificationPermissionResult != null) {
+            result.error(
+                "request_in_progress",
+                "Notification permission request is already in progress",
+                null,
+            )
+            return
+        }
+
+        if (ContextCompat.checkSelfPermission(this, Manifest.permission.POST_NOTIFICATIONS) ==
+            PackageManager.PERMISSION_GRANTED
+        ) {
+            result.success(getNotificationPermissionStatusValue())
+            return
+        }
+
+        pendingNotificationPermissionResult = result
+        ActivityCompat.requestPermissions(
+            this,
+            arrayOf(Manifest.permission.POST_NOTIFICATIONS),
+            notificationPermissionRequestCode,
+        )
+    }
+
+    private fun getNotificationPermissionStatusValue(): String {
+        if (isNotificationPermissionEnabled()) {
+            return "enabled"
+        }
+
+        val runtimePermissionGranted =
+            Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU ||
+                ContextCompat.checkSelfPermission(
+                    this,
+                    Manifest.permission.POST_NOTIFICATIONS,
+                ) == PackageManager.PERMISSION_GRANTED
+
+        return if (!runtimePermissionGranted) {
+            "requestable"
+        } else {
+            "settings_required"
+        }
+    }
+
     private fun isNotificationPermissionEnabled(): Boolean {
         val runtimePermissionGranted =
             Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU ||
@@ -95,4 +163,8 @@ class MainActivity : FlutterActivity() {
         return runtimePermissionGranted &&
             NotificationManagerCompat.from(this).areNotificationsEnabled()
     }
+
+    companion object {
+        private const val notificationPermissionRequestCode = 4102
+    }
 }