common: Add account settings

common/lib/src/backend.dart

@@ -141,6 +141,19 @@ class MusicusBackendState extends State<MusicusBackend> {
       _updateClient(serverSettings);
     });
 
+    settings.account.listen((accountSettings) {
+      if (accountSettings != null) {
+        client.user = User(
+          name: accountSettings.username,
+          email: accountSettings.email,
+          password: accountSettings.password,
+        );
+      } else {
+        client.user = null;
+      }
+    });
+
+    // This will also check for existing account settings.
     _updateClient(settings.server.value);
 
     final path = settings.musicLibraryPath.value;
@@ -168,13 +181,26 @@ class MusicusBackendState extends State<MusicusBackend> {
     }
   }
 
-  /// Create a new client based on [settings].
-  void _updateClient(MusicusServerSettings settings) {
+  /// Create a new client based on [serverSettings].
+  void _updateClient(MusicusServerSettings serverSettings) {
     client?.dispose();
+
+    User user;
+
+    final accountSettings = settings.account.value;
+    if (accountSettings != null) {
+      user = User(
+        name: accountSettings.username,
+        email: accountSettings.email,
+        password: accountSettings.password,
+      );
+    }
+
     client = MusicusClient(
-      host: settings.host,
-      port: settings.port,
-      basePath: settings.apiPath,
+      host: serverSettings.host,
+      port: serverSettings.port,
+      basePath: serverSettings.apiPath,
+      user: user,
     );
   }
 

common/lib/src/settings.dart

@@ -1,3 +1,5 @@
+import 'dart:convert';
+
 import 'package:meta/meta.dart';
 import 'package:rxdart/rxdart.dart';
 
@@ -36,6 +38,24 @@ class MusicusServerSettings {
   });
 }
 
+/// Settings concerning the Musicus account.
+class MusicusAccountSettings {
+  /// The user name to login as.
+  final String username;
+
+  /// An optional email address.
+  final String email;
+
+  /// The password for authentication.
+  final String password;
+
+  MusicusAccountSettings({
+    this.username,
+    this.email,
+    this.password,
+  });
+}
+
 /// Manager for all settings that are persisted.
 class MusicusSettings {
   static const defaultHost = 'musicus.johrpan.de';
@@ -54,6 +74,9 @@ class MusicusSettings {
   /// Musicus server to connect to.
   final server = BehaviorSubject<MusicusServerSettings>();
 
+  /// Musicus account to login with.
+  final account = BehaviorSubject<MusicusAccountSettings>();
+
   /// Create a settings instance.
   MusicusSettings(this.storage);
 
@@ -75,6 +98,18 @@ class MusicusSettings {
       port: port,
       apiPath: apiPath,
     ));
+
+    final username = await storage.getString('accountUsername');
+    final email = await storage.getString('accountEmail');
+    final passwordBase64 = await storage.getString('accountPassword');
+
+    if (username != null) {
+      account.add(MusicusAccountSettings(
+        username: username,
+        email: email,
+        password: utf8.decode(base64Decode(passwordBase64)),
+      ));
+    }
   }
 
   /// Set a new music library path.
@@ -104,9 +139,37 @@ class MusicusSettings {
     ));
   }
 
+  /// Update the account settings.
+  ///
+  /// This will persist the new values and update the stream.
+  Future<void> setAccount(MusicusAccountSettings accountSettings) async {
+    await storage.setString('accountUsername', accountSettings.username);
+    await storage.setString('accountEmail', accountSettings.email);
+
+    // IMPORTANT NOTE: We encode the password using Base64 to defend just the
+    // simplest of simplest attacks. This provides no additional security
+    // besides the fact that the password looks a little bit encrypted.
+    await storage.setString(
+      'accountPassword',
+      base64Encode(utf8.encode(accountSettings.password)),
+    );
+
+    account.add(accountSettings);
+  }
+
+  /// Delete the current account settings.
+  Future<void> clearAccount() async {
+    await storage.setString('accountUsername', null);
+    await storage.setString('accountEmail', null);
+    await storage.setString('accountPassword', null);
+
+    account.add(null);
+  }
+
   /// Tidy up.
   void dispose() {
     musicLibraryPath.close();
     server.close();
+    account.close();
   }
 }