feat(windows) : WP-D.3, BLE sous Windows et le PC qui rejoint seul le réseau d'un téléphone

app/lib/features/connect/hotspot_screen.dart

@@ -7,6 +7,7 @@ library;
 
 import 'dart:async';
 
+import 'package:flutter/foundation.dart' show TargetPlatform, defaultTargetPlatform;
 import 'package:flutter/material.dart';
 
 import '../../app.dart';
@@ -28,6 +29,9 @@ class _HotspotScreenState extends State<HotspotScreen> {
   late final Connection _c;
   bool _pinTab = false;
 
+  /// Android names the network itself; a computer's screen needs a larger code.
+  bool get _phone => defaultTargetPlatform == TargetPlatform.android;
+
   @override
   void initState() {
     super.initState();
@@ -203,7 +207,7 @@ class _HotspotScreenState extends State<HotspotScreen> {
                         decoration: BoxDecoration(color: Colors.white, borderRadius: BorderRadius.circular(20)),
                         // A computer's screen shows it at about 1 mm a module at 230 (real test of
                         // 29 October 2026): the camera needs to be close, where it cannot focus.
-                        child: SizedBox.square(dimension: _c.hotspot.canJoin ? 230 : 340, child: QrView(key: const Key('my-qr'), data: _c.qrData!)),
+                        child: SizedBox.square(dimension: _phone ? 230 : 340, child: QrView(key: const Key('my-qr'), data: _c.qrData!)),
                       ),
                     ),
                     const SizedBox(height: 14),
@@ -219,7 +223,7 @@ class _HotspotScreenState extends State<HotspotScreen> {
                           _Field(label: l.networkLabel, value: h.ssid ?? '', valueKey: const Key('hotspot-ssid')),
                           _Field(label: l.passwordLabel, value: h.passphrase ?? '', valueKey: const Key('hotspot-password')),
                           const SizedBox(height: 4),
-                          Text(_c.hotspot.canJoin ? l.chosenByAndroid : l.chosenByApp, style: TextStyle(color: c.muted, fontSize: 12)),
+                          Text(_phone ? l.chosenByAndroid : l.chosenByApp, style: TextStyle(color: c.muted, fontSize: 12)),
                         ],
                       ),
                     ),

app/lib/platform/ble.dart

@@ -78,9 +78,10 @@ abstract interface class Ble {
   Future<WifiBands> wifiBands();
 }
 
-/// Android: android.bluetooth.le, through the app's Kotlin (Ble.kt).
-class AndroidBle implements Ble {
-  AndroidBle({this.channel = const MethodChannel('dev.medxfer.app/ble')}) {
+/// Android (android.bluetooth.le, the app's Kotlin: Ble.kt) and Windows (Windows.Devices.Bluetooth,
+/// the runner's C++/WinRT: ble.cpp), by one channel.
+class ChannelBle implements Ble {
+  ChannelBle({this.channel = const MethodChannel('dev.medxfer.app/ble')}) {
     channel.setMethodCallHandler((call) async {
       if (call.method != 'event') return;
       final m = Map<Object?, Object?>.from(call.arguments as Map);
@@ -100,7 +101,7 @@ class AndroidBle implements Ble {
   final _events = StreamController<BleEvent>.broadcast();
 
   @override
-  bool get supported => Platform.isAndroid;
+  bool get supported => Platform.isAndroid || Platform.isWindows;
 
   @override
   Future<bool> enabled() async => await channel.invokeMethod<bool>('enabled') ?? false;
@@ -175,4 +176,4 @@ class NoBle implements Ble {
   Future<WifiBands> wifiBands() async => (create: 0, join: 0);
 }
 
-Ble systemBle() => Platform.isAndroid ? AndroidBle() : const NoBle();
+Ble systemBle() => Platform.isAndroid || Platform.isWindows ? ChannelBle() : const NoBle();

app/lib/platform/hotspot.dart

@@ -3,8 +3,8 @@
 /// hotspot (WP-D.4 of the J6d plan). Windows and Linux (WP-C.2 of the J6c plan): a network
 /// the computer creates at 2.4 GHz, its cards refusing 5 GHz on their own (probe WP-C.1);
 /// Windows by Wi-Fi Direct with a name and passphrase of the app's (decision C4), Linux by
-/// NetworkManager. A computer does not join another's network itself: the user does, in the
-/// system's settings ([Hotspot.canJoin]).
+/// NetworkManager. Joining another's network: Android and Windows (WP-D.3 of the J6d plan) do it
+/// themselves; on Linux the user does, in the system's settings ([Hotspot.canJoin]).
 library;
 
 import 'dart:io';
@@ -97,8 +97,8 @@ abstract interface class Hotspot {
   /// This device creates a network ([start]).
   bool get supported;
 
-  /// This device joins another's network itself ([join]): Android. A desktop's user joins it
-  /// in the system's settings.
+  /// This device joins another's network itself ([join]): Android, Windows. Linux's user joins
+  /// it in the system's settings.
   bool get canJoin;
 
   /// The Wi-Fi this device is on is left while the network runs, and comes back at [stop]:
@@ -281,6 +281,8 @@ class NoHotspot implements Hotspot {
 /// Windows serves the addresses on it, through its connection sharing, and accepts the phones.
 /// When that sharing is taken by another card, it serves none: [DhcpServer] does, on the group's
 /// address only, and Windows drops each phone after 2 minutes ([HotspotInfo.dropsClients]).
+/// Another device's network is joined through Windows' Wi-Fi API (wifi_join.cpp), with a profile
+/// of this user's that leaving deletes; the computer then goes back to its network.
 class WindowsHotspot implements Hotspot {
   WindowsHotspot({this.channel = const MethodChannel('dev.medxfer.app/hotspot'), AddressServer? addressServer})
       : _addressServer = addressServer ?? _dhcpServer;
@@ -293,7 +295,7 @@ class WindowsHotspot implements Hotspot {
   bool get supported => true;
 
   @override
-  bool get canJoin => false;
+  bool get canJoin => true;
 
   @override
   bool get leavesWifi => false;
@@ -339,11 +341,26 @@ class WindowsHotspot implements Hotspot {
   }
 
   @override
-  Future<HotspotInfo> join(String ssid, String passphrase, {int security = 1, WifiBand? band}) => throw UnsupportedError('a computer joins in the system settings');
+  Future<HotspotInfo> join(String ssid, String passphrase, {int security = 1, WifiBand? band}) async {
+    final m = (await channel.invokeMapMethod<String, Object?>(
+        'join', {'ssid': ssid, 'passphrase': passphrase, 'security': security, if (band != null) 'band': band.code}))!;
+    final address = '${m['address']}';
+    final prefix = (m['prefix'] as num?)?.toInt() ?? 24;
+    return HotspotInfo(
+      ssid: ssid,
+      passphrase: passphrase,
+      security: security,
+      address: address,
+      interfaces: ['${m['name']}'],
+      net: NetInterface(name: '${m['name']}', index: (m['index'] as num?)?.toInt() ?? 0, addrs: ['$address/$prefix']),
+      band: WifiBand.of((m['frequency'] as num?)?.toInt() ?? 0),
+    );
+  }
 
   @override
-  Future<void> leave() async {}
+  Future<void> leave() => channel.invokeMethod<void>('leave');
 
+  /// The core's sockets follow Windows' routes: the card that joined is the computer's Wi-Fi.
   @override
   Future<int> joinedNetwork() async => 0;
 

app/test/platform/hotspot_test.dart

@@ -131,6 +131,26 @@ void main() {
       expect(served.last, 'closed');
       expect(calls, ['start', 'stop']);
     });
+
+    test('WP-D.3: joins another device\'s network itself, its band said; leaving goes back', () async {
+      Object? asked;
+      TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger.setMockMethodCallHandler(channel, (call) async {
+        calls.add(call.method);
+        if (call.method == 'join') asked = call.arguments;
+        return switch (call.method) {
+          'join' => {'name': 'Wi-Fi', 'index': 12, 'address': '192.168.49.23', 'prefix': 24, 'frequency': 5745},
+          _ => null,
+        };
+      });
+      final h = WindowsHotspot(addressServer: (server, prefix) async => () {});
+      expect(h.canJoin, isTrue);
+      final info = await h.join('DIRECT-ab-Galaxy', 'K3PQ8Z2M', security: 1, band: WifiBand.ghz5);
+      expect(asked, {'ssid': 'DIRECT-ab-Galaxy', 'passphrase': 'K3PQ8Z2M', 'security': 1, 'band': '5'});
+      expect((info.address, info.band, info.net!.index), ('192.168.49.23', WifiBand.ghz5, 12));
+      expect(info.net!.addrs, ['192.168.49.23/24']);
+      await h.leave();
+      expect(calls, ['join', 'leave']);
+    });
   });
 
   group('WP-D.4: Android, the Wi-Fi Direct group at 5 GHz or the local hotspot', () {

app/windows/runner/CMakeLists.txt

@@ -7,11 +7,13 @@ project(runner LANGUAGES CXX)
 #
 # Any new source files that you add to the application should be added here.
 add_executable(${BINARY_NAME} WIN32
+  "ble.cpp"
   "firewall.cpp"
   "flutter_window.cpp"
   "hotspot.cpp"
   "main.cpp"
   "utils.cpp"
+  "wifi_join.cpp"
   "win32_window.cpp"
   "wired.cpp"
   "${FLUTTER_MANAGED_DIR}/generated_plugin_registrant.cc"
@@ -42,6 +44,8 @@ target_link_libraries(${BINARY_NAME} PRIVATE "dwmapi.lib")
 target_link_libraries(${BINARY_NAME} PRIVATE "windowsapp.lib" "iphlpapi.lib" "ws2_32.lib")
 # Windows' firewall and its networks (firewall.cpp): COM, BSTR and VARIANT.
 target_link_libraries(${BINARY_NAME} PRIVATE "ole32.lib" "oleaut32.lib")
+# Joining another device's network (wifi_join.cpp): Windows' Wi-Fi API.
+target_link_libraries(${BINARY_NAME} PRIVATE "wlanapi.lib")
 target_compile_features(${BINARY_NAME} PRIVATE cxx_std_20)
 target_include_directories(${BINARY_NAME} PRIVATE "${CMAKE_SOURCE_DIR}")