feat: notify keys

lib/widgets/notifications_button.dart

@@ -0,0 +1,57 @@
+import 'package:flutter/material.dart';
+import 'package:zap_stream_flutter/notifications.dart';
+import 'package:zap_stream_flutter/theme.dart';
+import 'package:zap_stream_flutter/utils.dart';
+
+class NotificationsButtonWidget extends StatefulWidget {
+  final StreamEvent stream;
+
+  const NotificationsButtonWidget({super.key, required this.stream});
+
+  @override
+  State<StatefulWidget> createState() => _NotificationsButtonWidget();
+}
+
+class _NotificationsButtonWidget extends State<NotificationsButtonWidget> {
+  @override
+  Widget build(BuildContext context) {
+    return FutureBuilder(
+      future: () async {
+        final n = getNotificationService();
+        return await n?.getWatchedKeys();
+      }(),
+      builder: (context, state) {
+        if (state.data == null) {
+          return SizedBox.shrink();
+        } else {
+          final isNotified = (state.data ?? []).contains(
+            widget.stream.info.host,
+          );
+          return IconButton(
+            iconSize: 20,
+            onPressed: () async {
+              final n = getNotificationService();
+              if (n == null) return;
+
+              if (isNotified) {
+                await n.removeWatchPubkey(widget.stream.info.host);
+              } else {
+                await n.watchPubkey(widget.stream.info.host, [30311]);
+              }
+              setState(() {
+                // reload widget
+              });
+            },
+            style: ButtonStyle(
+              padding: WidgetStatePropertyAll(EdgeInsets.all(0)),
+              backgroundColor: WidgetStateColor.resolveWith((_) => LAYER_2),
+            ),
+            icon: Icon(
+              isNotified ? Icons.notifications_off : Icons.notification_add,
+            ),
+          );
+        }
+      },
+    );
+  }
+}