🧱 OpenID Connect client infra

lib/screens/auth/oidc.web.dart

@@ -0,0 +1,78 @@
+// ignore_for_file: invalid_runtime_check_with_js_interop_types
+
+import 'dart:ui_web' as ui;
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:easy_localization/easy_localization.dart';
+import 'package:island/pods/config.dart';
+import 'package:island/widgets/app_scaffold.dart';
+import 'package:web/web.dart' as web;
+import 'package:flutter/material.dart';
+
+class OidcScreen extends ConsumerStatefulWidget {
+  final String provider;
+
+  const OidcScreen({super.key, required this.provider});
+
+  @override
+  ConsumerState<OidcScreen> createState() => _OIDCScreenState();
+}
+
+class _OIDCScreenState extends ConsumerState<OidcScreen> {
+  bool _isInitialized = false;
+  final String _viewType = 'oidc-iframe';
+
+  void _setupWebListener(String serverUrl) {
+    // Listen for messages from the iframe
+    web.window.onMessage.listen((event) {
+      if (event.data != null && event.data is String) {
+        final message = event.data as String;
+        if (message.startsWith("token=")) {
+          String token = message.replaceFirst("token=", "");
+          // Return the token and close the screen
+          if (context.mounted) Navigator.pop(context, token);
+        }
+      }
+    });
+
+    // Create the iframe for the OIDC login
+    final iframe =
+        web.HTMLIFrameElement()
+          ..src = '$serverUrl/auth/login/${widget.provider}'
+          ..style.border = 'none'
+          ..width = '100%'
+          ..height = '100%';
+
+    // Add the iframe to the document body
+    web.document.body!.append(iframe);
+
+    // Register the iframe as a platform view
+    ui.platformViewRegistry.registerViewFactory(
+      _viewType,
+      (int viewId) => iframe,
+    );
+
+    setState(() {
+      _isInitialized = true;
+    });
+  }
+
+  @override
+  void initState() {
+    super.initState();
+    Future.delayed(Duration.zero, () {
+      final serverUrl = ref.watch(serverUrlProvider);
+      _setupWebListener(serverUrl);
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AppScaffold(
+      appBar: AppBar(title: Text('login').tr()),
+      body:
+          _isInitialized
+              ? HtmlElementView(viewType: _viewType)
+              : Center(child: CircularProgressIndicator()),
+    );
+  }
+}