On launch, go to the last visited account

lib/model/actions.dart

@@ -4,6 +4,7 @@ import 'package:flutter/foundation.dart';
 
 import '../notifications/display.dart';
 import '../notifications/receive.dart';
+import 'settings.dart';
 import 'store.dart';
 
 // TODO: Make this a part of GlobalStore
@@ -21,6 +22,18 @@ Future<void> logOutAccount(GlobalStore globalStore, int accountId) async {
   await globalStore.removeAccount(accountId);
 }
 
+Future<void> removeLastVisitedAccountIfNecessary(GlobalStore store, int loggedOutAccountId) async {
+  // If account is not logged out yet, do nothing.
+  if (store.getAccount(loggedOutAccountId) != null) return;
+
+  // If the logged-out account is different than the last visited one, do nothing.
+  if (loggedOutAccountId != store.settings.getInt(IntGlobalSetting.lastVisitedAccountId)) {
+    return;
+  }
+
+  await store.settings.setInt(IntGlobalSetting.lastVisitedAccountId, null);
+}
+
 Future<void> unregisterToken(GlobalStore globalStore, int accountId) async {
   final account = globalStore.getAccount(accountId);
   if (account == null) return; // TODO(log)

lib/model/database.dart

@@ -35,7 +35,8 @@ class GlobalSettings extends Table {
     .nullable()();
 
   // If adding a new column to this table, consider whether [BoolGlobalSettings]
-  // can do the job instead (by adding a value to the [BoolGlobalSetting] enum).
+  // or [IntGlobalSettings] can do the job instead (by adding a value to the
+  // [BoolGlobalSetting] or [IntGlobalSetting] enum).
   // That way is more convenient, when it works, because
   // it avoids a migration and therefore several added copies of our schema
   // in the Drift generated files.
@@ -50,6 +51,9 @@ class GlobalSettings extends Table {
 /// referring to a possible setting from [BoolGlobalSetting].
 /// For settings in [BoolGlobalSetting] without a row in this table,
 /// the setting's value is that of [BoolGlobalSetting.default_].
+///
+/// See also:
+/// - [IntGlobalSettings], the int-valued counterpart of this table.
 @DataClassName('BoolGlobalSettingRow')
 class BoolGlobalSettings extends Table {
   /// The setting's name, a possible name from [BoolGlobalSetting].
@@ -73,6 +77,37 @@ class BoolGlobalSettings extends Table {
   Set<Column<Object>>? get primaryKey => {name};
 }
 
+/// The table of the user's int-valued, account-independent settings.
+///
+/// These apply across all the user's accounts on this client
+/// (i.e. on this install of the app on this device).
+///
+/// Each row is a [IntGlobalSettingRow],
+/// referring to a possible setting from [IntGlobalSetting].
+/// For settings in [IntGlobalSetting] without a row in this table,
+/// the setting's value is `null`.
+///
+/// See also:
+/// - [BoolGlobalSettings], the bool-valued counterpart of this table.
+@DataClassName('IntGlobalSettingRow')
+class IntGlobalSettings extends Table {
+  /// The setting's name, a possible name from [IntGlobalSetting].
+  ///
+  /// The table may have rows where [name] is not the name of any
+  /// enum value in [IntGlobalSetting].
+  /// This happens if the app has previously run at a future or modified
+  /// version which had additional values in that enum,
+  /// and the user set one of those additional settings.
+  /// The app ignores any such unknown rows.
+  TextColumn get name => text()();
+
+  /// The user's chosen value for the setting.
+  IntColumn get value => integer()();
+
+  @override
+  Set<Column<Object>>? get primaryKey => {name};
+}
+
 /// The table of [Account] records in the app's database.
 class Accounts extends Table {
   /// The ID of this account in the app's local database.
@@ -116,7 +151,7 @@ class UriConverter extends TypeConverter<Uri, String> {
   @override Uri fromSql(String fromDb) => Uri.parse(fromDb);
 }
 
-@DriftDatabase(tables: [GlobalSettings, BoolGlobalSettings, Accounts])
+@DriftDatabase(tables: [GlobalSettings, BoolGlobalSettings, IntGlobalSettings, Accounts])
 class AppDatabase extends _$AppDatabase {
   AppDatabase(super.e);
 
@@ -129,7 +164,7 @@ 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 +235,10 @@ 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.intGlobalSettings);
+    },
   );
 
   Future<void> _createLatestSchema(Migrator m) async {
@@ -256,6 +294,14 @@ class AppDatabase extends _$AppDatabase {
     return result;
   }
 
+  Future<Map<IntGlobalSetting, int>> getIntGlobalSettings() async {
+    return {
+      for (final row in await select(intGlobalSettings).get())
+        if (IntGlobalSetting.byName(row.name) case final setting?)
+          setting: row.value
+    };
+  }
+
   Future<int> createAccount(AccountsCompanion values) async {
     try {
       return await into(accounts).insert(values);