🗃️ Local keypair db

lib/database/keypair.dart

@@ -0,0 +1,39 @@
+import 'dart:convert';
+
+import 'package:drift/drift.dart';
+import 'package:surface/types/keypair.dart';
+
+class SnKeyPairConverter extends TypeConverter<SnKeyPair, String>
+    with JsonTypeConverter2<SnKeyPair, String, Map<String, Object?>> {
+  const SnKeyPairConverter();
+
+  @override
+  SnKeyPair fromSql(String fromDb) {
+    return fromJson(jsonDecode(fromDb) as Map<String, dynamic>);
+  }
+
+  @override
+  String toSql(SnKeyPair value) {
+    return jsonEncode(toJson(value));
+  }
+
+  @override
+  SnKeyPair fromJson(Map<String, Object?> json) {
+    return SnKeyPair.fromJson(json);
+  }
+
+  @override
+  Map<String, Object?> toJson(SnKeyPair value) {
+    return value.toJson();
+  }
+}
+
+class SnLocalKeyPair extends Table {
+  TextColumn get id => text()();
+
+  IntColumn get accountId => integer()();
+
+  TextColumn get publicKey => text()();
+
+  TextColumn get privateKey => text().nullable()();
+}