db: Store Navigation (last visited account id) in database

Author: sm-sayedi

lib/model/database.dart

@@ -110,13 +110,23 @@ class Accounts extends Table {
   ];
 }
 
+/// The table of one [NavigationData] record, the user's last visited account.
+///
+/// These apply across all the user's accounts on this client (i.e. on this
+/// install of the app on this device).
+///
+/// This table can have at most one row.
+class Navigation extends Table {
+  IntColumn get accountId => integer().nullable()();
+}
+
 class UriConverter extends TypeConverter<Uri, String> {
   const UriConverter();
   @override String toSql(Uri value) => value.toString();
   @override Uri fromSql(String fromDb) => Uri.parse(fromDb);
 }
 
-@DriftDatabase(tables: [GlobalSettings, BoolGlobalSettings, Accounts])
+@DriftDatabase(tables: [GlobalSettings, BoolGlobalSettings, Accounts, Navigation])
 class AppDatabase extends _$AppDatabase {
   AppDatabase(super.e);
 
@@ -129,7 +139,7 @@ class AppDatabase extends _$AppDatabase {
   //    information on using the build_runner.
   //  * Write a migration in `_migrationSteps` below.
   //  * Write tests.
-  static const int latestSchemaVersion = 9; // See note.
+  static const int latestSchemaVersion = 10; // See note.
 
   @override
   int get schemaVersion => latestSchemaVersion;
@@ -200,7 +210,10 @@ class AppDatabase extends _$AppDatabase {
       // assume there wasn't also the legacy app before that.
       await m.database.update(schema.globalSettings).write(
         RawValuesInsertable({'legacy_upgrade_state': Constant('noLegacy')}));
-    }
+    },
+    from9To10: (m, schema) async {
+      await m.createTable(schema.navigation);
+    },
   );
 
   Future<void> _createLatestSchema(Migrator m) async {
@@ -271,6 +284,10 @@ class AppDatabase extends _$AppDatabase {
       rethrow;
     }
   }
+
+  Future<NavigationData?> getNavigation() async {
+    return await (select(navigation)..limit(1)).getSingleOrNull();
+  }
 }
 
 class AccountAlreadyExistsException implements Exception {}