feat(watch): Android Wear Data Layer adapter + foreground service (#91-D)

lib/infrastructure/watch_bridge/native_watch_bridge_channel.dart

@@ -0,0 +1,137 @@
+import 'dart:async';
+
+import 'package:flutter/services.dart';
+import 'package:watch_bridge_contract/watch_bridge_contract.dart';
+
+final class WatchBridgeConnectionEvent {
+  const WatchBridgeConnectionEvent({
+    required this.isReachable,
+    this.requestsResync = false,
+  });
+
+  final bool isReachable;
+  final bool requestsResync;
+}
+
+abstract interface class WatchBridgeNativeChannel {
+  Stream<WatchCommandEnvelope> get commands;
+
+  Stream<WatchBridgeConnectionEvent> get connectionEvents;
+
+  Future<void> publishProjection(WatchSessionProjection projection);
+
+  Future<void> sendCommandAck(
+    WatchCommandEnvelope command,
+    WatchCommandAck ack, {
+    int? revisionAtAck,
+  });
+
+  Future<void> requestCapabilityRefresh();
+
+  Future<void> startForegroundService();
+
+  Future<void> stopForegroundService();
+}
+
+final class MethodChannelWatchBridgeNativeChannel
+    implements WatchBridgeNativeChannel {
+  const MethodChannelWatchBridgeNativeChannel({
+    MethodChannel methodChannel = const MethodChannel(_methodChannelName),
+    EventChannel commandChannel = const EventChannel(_commandChannelName),
+    EventChannel connectionChannel = const EventChannel(_connectionChannelName),
+  }) : _methodChannel = methodChannel,
+       _commandChannel = commandChannel,
+       _connectionChannel = connectionChannel;
+
+  static const _methodChannelName = 'gametime.watch_bridge/methods';
+  static const _commandChannelName = 'gametime.watch_bridge/commands';
+  static const _connectionChannelName = 'gametime.watch_bridge/connection';
+
+  final MethodChannel _methodChannel;
+  final EventChannel _commandChannel;
+  final EventChannel _connectionChannel;
+
+  @override
+  Stream<WatchCommandEnvelope> get commands {
+    return _commandChannel
+        .receiveBroadcastStream()
+        .where((event) {
+          return event is Map;
+        })
+        .map((event) {
+          return WatchCommandEnvelope.fromJson(_stringObjectMap(event));
+        });
+  }
+
+  @override
+  Stream<WatchBridgeConnectionEvent> get connectionEvents {
+    return _connectionChannel
+        .receiveBroadcastStream()
+        .where((event) {
+          return event is Map;
+        })
+        .map((event) {
+          final json = _stringObjectMap(event);
+          return WatchBridgeConnectionEvent(
+            isReachable: json['isReachable'] == true,
+            requestsResync: json['requestsResync'] == true,
+          );
+        });
+  }
+
+  @override
+  Future<void> publishProjection(WatchSessionProjection projection) {
+    return _invokeIgnoringMissingPlugin(
+      'publishProjection',
+      projection.toJson(),
+    );
+  }
+
+  @override
+  Future<void> requestCapabilityRefresh() {
+    return _invokeIgnoringMissingPlugin('requestCapabilityRefresh');
+  }
+
+  @override
+  Future<void> sendCommandAck(
+    WatchCommandEnvelope command,
+    WatchCommandAck ack, {
+    int? revisionAtAck,
+  }) {
+    return _invokeIgnoringMissingPlugin('sendCommandAck', {
+      'schemaVersion': watchBridgeSchemaVersion,
+      'commandId': command.commandId,
+      'sessionId': command.sessionId,
+      'expectedRevision': command.expectedRevision,
+      'status': ack.name,
+      'revisionAtAck': revisionAtAck,
+      'ackedAtEpochMs': DateTime.now().toUtc().millisecondsSinceEpoch,
+    });
+  }
+
+  @override
+  Future<void> startForegroundService() {
+    return _invokeIgnoringMissingPlugin('startForegroundService');
+  }
+
+  @override
+  Future<void> stopForegroundService() {
+    return _invokeIgnoringMissingPlugin('stopForegroundService');
+  }
+
+  Future<void> _invokeIgnoringMissingPlugin(
+    String method, [
+    Object? arguments,
+  ]) {
+    return _methodChannel
+        .invokeMethod<void>(method, arguments)
+        .onError<MissingPluginException>((_, _) {});
+  }
+}
+
+Map<String, Object?> _stringObjectMap(Object? value) {
+  if (value is Map) {
+    return value.map((key, value) => MapEntry(key.toString(), value));
+  }
+  return const {};
+}