mobile: Add Musicus client

The settings screen now contains a tile to change the URL of the Musicus
server.

mobile/lib/backend.dart

@@ -6,9 +6,11 @@ import 'package:flutter/widgets.dart';
 import 'package:moor/isolate.dart';
 import 'package:moor/moor.dart';
 import 'package:moor_ffi/moor_ffi.dart';
+import 'package:musicus_client/musicus_client.dart';
 import 'package:musicus_database/musicus_database.dart';
 import 'package:path/path.dart' as p;
 import 'package:path_provider/path_provider.dart' as pp;
+import 'package:rxdart/rxdart.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 import 'music_library.dart';
@@ -86,6 +88,10 @@ class BackendState extends State<Backend> {
 
   BackendStatus status = BackendStatus.loading;
   Database db;
+
+  final musicusServerUrl = BehaviorSubject<String>();
+  MusicusClient client;
+
   String musicLibraryUri;
   MusicLibrary ml;
 
@@ -113,6 +119,12 @@ class BackendState extends State<Backend> {
     db = Database.connect(dbConnection);
 
     _shPref = await SharedPreferences.getInstance();
+    final url = _shPref.getString('musicusServerUrl');
+    musicusServerUrl.add(url);
+    if (url != null) {
+      client = MusicusClient(url);
+    }
+
     musicLibraryUri = _shPref.getString('musicLibraryUri');
 
     _loadMusicLibrary();
@@ -145,9 +157,25 @@ class BackendState extends State<Backend> {
     }
   }
 
+  Future<void> setMusicusServer(String serverUrl) async {
+    final url = serverUrl.isNotEmpty ? serverUrl : null;
+    await _shPref.setString('musicusServerUrl', url);
+
+    if (client != null) {
+      client.dispose();
+    }
+
+    if (url != null) {
+      client = MusicusClient(url);
+    }
+
+    musicusServerUrl.add(url);
+  }
+
   @override
   void dispose() {
     super.dispose();
+    client.dispose();
     _moorIsolate.shutdownAll();
   }
 }

mobile/lib/screens/settings.dart

@@ -21,6 +21,52 @@ class SettingsScreen extends StatelessWidget {
               backend.chooseMusicLibraryUri();
             },
           ),
+          StreamBuilder<String>(
+            stream: backend.musicusServerUrl,
+            builder: (context, snapshot) {
+              return ListTile(
+                leading: Icon(Icons.router),
+                title: Text('Musicus server'),
+                subtitle: Text(snapshot.data ?? 'Set server URL'),
+                onTap: () {
+                  showDialog(
+                      context: context,
+                      builder: (context) {
+                        final controller = TextEditingController();
+
+                        if (snapshot.data != null) {
+                          controller.text = snapshot.data;
+                        }
+
+                        return AlertDialog(
+                          title: Text('Musicus server'),
+                          content: TextField(
+                            controller: controller,
+                            decoration: InputDecoration(
+                              labelText: 'Server URL',
+                            ),
+                          ),
+                          actions: <Widget>[
+                            FlatButton(
+                              onPressed: () {
+                                backend.setMusicusServer(controller.text);
+                                Navigator.pop(context);
+                              },
+                              child: Text('SET'),
+                            ),
+                            FlatButton(
+                              onPressed: () {
+                                Navigator.pop(context);
+                              },
+                              child: Text('CANCEL'),
+                            ),
+                          ],
+                        );
+                      });
+                },
+              );
+            }
+          ),
         ],
       ),
     );

mobile/pubspec.yaml

@@ -14,6 +14,8 @@ dependencies:
     sdk: flutter
   moor:
   moor_ffi:
+  musicus_client:
+    path: ../client
   musicus_database:
     path: ../database
   musicus_player: