🧱 OpenID Connect client infra

lib/screens/auth/oidc.native.dart

@@ -0,0 +1,86 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_inappwebview/flutter_inappwebview.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:easy_localization/easy_localization.dart';
+import 'package:island/pods/config.dart';
+import 'package:island/widgets/app_scaffold.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> {
+  InAppWebViewController? _webViewController;
+  String? authToken;
+
+  @override
+  Widget build(BuildContext context) {
+    final serverUrl = ref.watch(serverUrlProvider);
+
+    return AppScaffold(
+      appBar: AppBar(title: Text('login').tr()),
+      body: InAppWebView(
+        initialUrlRequest: URLRequest(
+          url: WebUri('$serverUrl/auth/login/${widget.provider}'),
+        ),
+        onWebViewCreated: (controller) {
+          _webViewController = controller;
+
+          // Register a handler to receive the token from JavaScript
+          controller.addJavaScriptHandler(
+            handlerName: 'tokenHandler',
+            callback: (args) {
+              // args[0] will be the token string
+              if (args.isNotEmpty && args[0] is String) {
+                setState(() {
+                  authToken = args[0];
+                });
+
+                // Return the token and close the webview
+                Navigator.of(context).pop(authToken);
+              }
+            },
+          );
+        },
+        shouldOverrideUrlLoading: (controller, navigationAction) async {
+          final url = navigationAction.request.url;
+          if (url != null) {
+            final path = url.path;
+            final queryParams = url.queryParameters;
+
+            // Check if we're on the token page
+            if (path.contains('/auth/token') &&
+                queryParams.containsKey('token')) {
+              // Extract token from URL
+              final token = queryParams['token']!;
+
+              // Return the token and close the webview
+              Navigator.of(context).pop(token);
+              return NavigationActionPolicy.CANCEL;
+            }
+          }
+          return NavigationActionPolicy.ALLOW;
+        },
+        onLoadStop: (controller, url) async {
+          if (url != null && url.path.contains('/auth/token')) {
+            // Inject JavaScript to call our handler with the token
+            await controller.evaluateJavascript(
+              source: '''
+              const urlParams = new URLSearchParams(window.location.search);
+              const token = urlParams.get('token');
+              if (token) {
+                window.flutter_inappwebview.callHandler('tokenHandler', token);
+              }
+            ''',
+            );
+          }
+        },
+      ),
+    );
+  }
+}