Add discover page and button

lib/pages/discover_page.dart

@@ -0,0 +1,83 @@
+import 'dart:async';
+
+import 'package:bonsoir/bonsoir.dart';
+import 'package:flutter/material.dart';
+import 'package:rutorrentflutter/api/api_conf.dart';
+
+class DiscoverPage extends StatefulWidget {
+  @override
+  _DiscoverPageState createState() => _DiscoverPageState();
+}
+
+class _DiscoverPageState extends State<DiscoverPage> {
+  final BonsoirDiscovery zeroconfService =
+      BonsoirDiscovery(type: "_rutorrent_mobile._tcp");
+  final List<ResolvedBonsoirService> urls = [];
+  StreamSubscription zeroconfSub;
+
+  @override
+  void dispose() {
+    zeroconfSub?.cancel();
+    if (zeroconfService.isReady && !zeroconfService.isStopped) {
+      zeroconfService.stop();
+    }
+    super.dispose();
+  }
+
+  static buildURL(ResolvedBonsoirService resolved) {
+    // TODO: Enable password authentication
+    var protocol = resolved.attributes["protocol"];
+    var port = resolved.port;
+    if (port == 80) {
+      return "http://${resolved.ip}/";
+    } else if (port == 443) {
+      return "https://${resolved.ip}/";
+    } else {
+      if (protocol != null) {
+        return "$protocol://${resolved.ip}:${resolved.port}/";
+      } else {
+        return "http://${resolved.ip}:${resolved.port}";
+      }
+    }
+  }
+
+  void setupListener() {
+    zeroconfSub = zeroconfService.eventStream.listen((event) {
+      if (event.isServiceResolved &&
+          event.type == BonsoirDiscoveryEventType.DISCOVERY_SERVICE_RESOLVED) {
+        var resolved = event.service as ResolvedBonsoirService;
+        setState(() {
+          urls.add(resolved);
+        });
+      }
+    });
+    zeroconfService.start();
+  }
+
+  @override
+  void initState() {
+    zeroconfService.ready.then((_) => setupListener());
+    super.initState();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Dialog(
+      child: Container(
+          child: ListView.builder(
+        itemBuilder: (context, index) => ListTile(
+          title: Text(urls[index].name),
+          subtitle: Text("IP address: ${urls[index].ip}"),
+          onTap: () {
+            var api = Api();
+            api.setUrl(buildURL(urls[index]));
+            api.setUsername("");
+            api.setPassword("");
+            Navigator.of(context).pop(api);
+          },
+        ),
+        itemCount: urls.length,
+      )),
+    );
+  }
+}

lib/screens/configurations_screen.dart

@@ -7,6 +7,7 @@ import 'package:provider/provider.dart';
 import 'package:rutorrentflutter/components/data_input.dart';
 import 'package:rutorrentflutter/components/password_input.dart';
 import 'package:rutorrentflutter/models/mode.dart';
+import 'package:rutorrentflutter/pages/discover_page.dart';
 import 'package:rutorrentflutter/screens/main_screen.dart';
 import 'package:modal_progress_hud/modal_progress_hud.dart';
 import 'package:rutorrentflutter/utilities/preferences.dart';
@@ -215,6 +216,47 @@ class _ConfigurationsScreenState extends State<ConfigurationsScreen> {
                     passwordFocus: passwordFocus,
                   ),
                 ),
+                Padding(
+                  padding:
+                      const EdgeInsets.symmetric(vertical: 16, horizontal: 32),
+                  child: Container(
+                    width: double.infinity,
+                    child: ElevatedButton(
+                      style: ElevatedButton.styleFrom(
+                        shape: RoundedRectangleBorder(
+                          borderRadius: BorderRadius.circular(5.0),
+                          side:
+                              BorderSide(color: Theme.of(context).primaryColor),
+                        ),
+                        primary: Provider.of<Mode>(context).isLightMode
+                            ? Colors.white
+                            : Colors.black,
+                      ),
+                      child: Padding(
+                        padding: const EdgeInsets.symmetric(
+                            horizontal: 28, vertical: 16),
+                        child: Text(
+                          'Discover ruTorrent servers in LAN',
+                          style: TextStyle(
+                              color: Theme.of(context).primaryColor,
+                              fontSize: 18),
+                        ),
+                      ),
+                      onPressed: () async {
+                        var received = await showDialog<Api>(
+                            context: context, builder: (ctx) => DiscoverPage());
+                        if (received != null) {
+                          Api api = Provider.of<Api>(context,
+                              listen: false); // One call to provider
+                          api.setUrl(api.url);
+                          api.setUsername(api.username);
+                          api.setPassword(api.password);
+                          _validateConfigurationDetails(api);
+                        }
+                      },
+                    ),
+                  ),
+                ),
                 Padding(
                   padding:
                       const EdgeInsets.symmetric(vertical: 16, horizontal: 32),