persist pending remote sync actions until there are sent to the server (

#142)

lib/models/db.dart

@@ -6,6 +6,7 @@ import '../constants.dart';
 import 'app_log.dart';
 import 'article.dart';
 import 'article_scroll_position.dart';
+import 'remote_action.dart';
 
 typedef DBInstance = Isar;
 
@@ -18,7 +19,12 @@ class DB {
 
     final dir = await getApplicationDocumentsDirectory();
     _instance = await Isar.open(
-      [AppLogSchema, ArticleSchema, ArticleScrollPositionSchema],
+      [
+        AppLogSchema,
+        ArticleSchema,
+        ArticleScrollPositionSchema,
+        RemoteActionSchema,
+      ],
       directory: dir.path,
       name: 'frigoligo${devmode ? '-dev' : ''}',
     );

lib/models/remote_action.dart

@@ -0,0 +1,31 @@
+import 'dart:convert';
+
+import 'package:isar/isar.dart';
+
+import '../services/remote_sync_actions/base.dart';
+
+part 'remote_action.g.dart';
+
+@collection
+class RemoteAction {
+  RemoteAction();
+
+  Id? id;
+  DateTime? createdAt;
+  int? key;
+  String? className;
+  String? jsonParams;
+
+  factory RemoteAction.fromRSA(RemoteSyncAction action) {
+    return RemoteAction()
+      ..key = action.hashCode
+      ..createdAt = DateTime.now()
+      ..className = action.runtimeType.toString()
+      ..jsonParams = jsonEncode(action.params());
+  }
+
+  RemoteSyncAction toRSA() {
+    final json = jsonDecode(jsonParams!);
+    return RemoteSyncAction.fromParams(className!, json);
+  }
+}