Show a subtle donation snackbar

app/lib/pref.dart

@@ -267,6 +267,22 @@ class Pref {
       value,
       (key, value) => provider.setBool(key, value));
 
+  int? getLastDonationDialogTime() =>
+      provider.getInt(PrefKey.lastDonationDialogTime);
+  int getLastDonationDialogTimeOr(int def) =>
+      getLastDonationDialogTime() ?? def;
+  Future<bool> setLastDonationDialogTime(int value) =>
+      provider.setInt(PrefKey.lastDonationDialogTime, value);
+
+  bool? shouldRemindDonationLater() =>
+      provider.getBool(PrefKey.shouldRemindDonationLater);
+  bool shouldRemindDonationLaterOr([bool def = false]) =>
+      shouldRemindDonationLater() ?? def;
+  Future<bool> setShouldRemindDonationLater(bool value) => _set<bool>(
+      PrefKey.shouldRemindDonationLater,
+      value,
+      (key, value) => provider.setBool(key, value));
+
   Future<bool> _set<T>(PrefKey key, T value,
       Future<bool> Function(PrefKey key, T value) setFn) async {
     if (await setFn(key, value)) {
@@ -581,6 +597,8 @@ enum PrefKey {
   memoriesRange,
   saveEditResultToServer,
   hasShownSaveEditResultDialog,
+  lastDonationDialogTime,
+  shouldRemindDonationLater,
 
   // account pref
   isEnableFaceRecognitionApp,
@@ -656,6 +674,10 @@ extension on PrefKey {
         return "saveEditResultToServer";
       case PrefKey.hasShownSaveEditResultDialog:
         return "hasShownSaveEditResultDialog";
+      case PrefKey.lastDonationDialogTime:
+        return "lastDonationDialogTime";
+      case PrefKey.shouldRemindDonationLater:
+        return "shouldRemindDonationLater";
 
       // account pref
       case PrefKey.isEnableFaceRecognitionApp:

app/lib/widget/donation_dialog.dart

@@ -0,0 +1,50 @@
+import 'package:flutter/material.dart';
+import 'package:nc_photos/app_localizations.dart';
+import 'package:nc_photos/k.dart' as k;
+import 'package:nc_photos/object_extension.dart';
+import 'package:nc_photos/pref.dart';
+import 'package:nc_photos/snack_bar_manager.dart';
+
+class DonationDialogHandler {
+  Future<void> showIfNeeded(BuildContext context) async {
+    final lastMs = Pref().getLastDonationDialogTime();
+    if (lastMs == null) {
+      // first time
+      final firstRun =
+          (Pref().getFirstRunTime()?.run(DateTime.fromMillisecondsSinceEpoch) ??
+                  DateTime.now())
+              .toUtc();
+      final now = DateTime.now().toUtc();
+      if (now.isAfter(firstRun) &&
+          now.difference(firstRun) < const Duration(days: 7)) {
+        // unnecessary
+        return;
+      } else {
+        return _show(context);
+      }
+    } else {
+      final last = DateTime.fromMillisecondsSinceEpoch(lastMs, isUtc: true);
+      final now = DateTime.now().toUtc();
+      if (now.isAfter(last) &&
+          now.difference(last) < const Duration(days: 365)) {
+        return;
+      } else {
+        // 1 year later...
+        return _show(context);
+      }
+    }
+  }
+
+  Future<void> _show(BuildContext context) async {
+    SnackBarManager().showSnackBar(SnackBar(
+      content: Text(L10n.global().donationShortMessage),
+      action: SnackBarAction(
+        label: L10n.global().donationButtonLabel,
+        onPressed: () {},
+      ),
+      duration: k.snackBarDurationNormal,
+    ));
+    await Pref().setLastDonationDialogTime(
+        DateTime.now().toUtc().millisecondsSinceEpoch);
+  }
+}

app/lib/widget/home_photos.dart

@@ -39,6 +39,7 @@ import 'package:nc_photos/throttler.dart';
 import 'package:nc_photos/use_case/startup_sync.dart';
 import 'package:nc_photos/widget/album_browser_util.dart' as album_browser_util;
 import 'package:nc_photos/widget/builder/photo_list_item_builder.dart';
+import 'package:nc_photos/widget/donation_dialog.dart';
 import 'package:nc_photos/widget/handler/add_selection_to_album_handler.dart';
 import 'package:nc_photos/widget/handler/archive_selection_handler.dart';
 import 'package:nc_photos/widget/handler/double_tap_exit_handler.dart';
@@ -80,6 +81,10 @@ class _HomePhotosState extends State<HomePhotos>
     _web?.onInitState();
     _prefUpdatedListener.begin();
     _imageProcessorUploadSuccessListener?.begin();
+
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      DonationDialogHandler().showIfNeeded(context);
+    });
   }
 
   @override