feat: Provide a much cleaner Dart API

lib/src/service/background/base.dart

@@ -0,0 +1,16 @@
+import 'package:moxxy_native/src/service/config.dart';
+import 'package:moxxy_native/src/service/datasender/types.dart';
+
+/// Wrapper API that is only available to the background service.
+abstract class BackgroundService {
+  /// Send [event] with optional id [id] to the foreground.
+  Future<void> send(BackgroundEvent event, {String? id});
+
+  /// Platform specific initialization routine that is called after
+  /// the entrypoint has been called.
+  Future<void> init(ServiceConfig config);
+
+  /// Update the notification body, if the platform shows a persistent
+  /// notification.
+  void setNotificationBody(String body);
+}

lib/src/service/background/pigeon.dart

@@ -0,0 +1,58 @@
+import 'dart:convert';
+import 'dart:ui';
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
+import 'package:logging/logging.dart';
+import 'package:moxlib/moxlib.dart';
+import 'package:moxxy_native/pigeon/background_service.g.dart';
+import 'package:moxxy_native/src/service/background/base.dart';
+import 'package:moxxy_native/src/service/config.dart';
+import 'package:moxxy_native/src/service/datasender/types.dart';
+import 'package:uuid/uuid.dart';
+
+class PigeonBackgroundService extends BackgroundService {
+  final MoxxyBackgroundServiceApi _api = MoxxyBackgroundServiceApi();
+
+  /// A method channel for Foreground -> Service communication
+  // TODO(Unknown): Move this into a constant for reuse
+  final MethodChannel _channel =
+      const MethodChannel('org.moxxy.moxxy_native/background');
+
+  /// A logger.
+  final Logger _log = Logger('PigeonBackgroundService');
+
+  @override
+  Future<void> send(BackgroundEvent event, {String? id}) async {
+    final data = DataWrapper(
+      id ?? const Uuid().v4(),
+      event,
+    );
+
+    await _api.sendData(jsonEncode(data.toJson()));
+  }
+
+  @override
+  Future<void> init(
+    ServiceConfig config,
+  ) async {
+    // Ensure that the Dart executor is ready to use plugins
+    WidgetsFlutterBinding.ensureInitialized();
+    DartPluginRegistrant.ensureInitialized();
+
+    // Register the channel for Foreground -> Service communication
+    _channel.setMethodCallHandler((call) async {
+      // TODO(Unknown): Maybe do something smarter like pigeon and use Lists instead of Maps
+      final args = call.arguments! as String;
+      await config.handleData(jsonDecode(args) as Map<String, dynamic>);
+    });
+
+    // Start execution
+    _log.finest('Setup complete. Calling main entrypoint...');
+    await config.entrypoint(config.initialLocale);
+  }
+
+  @override
+  void setNotificationBody(String body) {
+    _api.setNotificationBody(body);
+  }
+}