import "dart:async";

import "package:app_links/app_links.dart";
import "package:auto_route/auto_route.dart";
import "package:flutter/material.dart";
import "package:flutter_riverpod/flutter_riverpod.dart";

import "package:smol_mail/data/providers/providers.dart";
import "package:smol_mail/presentation/routes/app_router.dart";
import "package:smol_mail/presentation/routes/app_router.gr.dart";
import "package:smol_mail/presentation/theme/theme.dart";
import "package:smol_mail/smol/link.dart";

/// SnackBars need no context through this key, so the client's trust
/// warnings can be shown from anywhere in the protocol stack.
final rootScaffoldMessengerKey = GlobalKey<ScaffoldMessengerState>();

class AppWidget extends ConsumerStatefulWidget {
  const AppWidget({super.key});

  @override
  ConsumerState<AppWidget> createState() => _AppWidgetState();
}

class _AppWidgetState extends ConsumerState<AppWidget> {
  late final AppRouter _router = AppRouter(ref);
  final AppLinks _appLinks = AppLinks();
  StreamSubscription<Uri>? _linkSub;

  @override
  void initState() {
    super.initState();
    // §4/§8 trust warnings stay on screen until dismissed; ordinary notices
    // do not use this channel.
    ref.read(clientProvider).onWarning = (message) {
      rootScaffoldMessengerKey.currentState?.showSnackBar(
        SnackBar(
          backgroundColor: const Color.fromRGBO(198, 40, 40, 1),
          content: Text(message, style: const TextStyle(color: Colors.white)),
          duration: const Duration(days: 1),
          action: SnackBarAction(
            label: "Dismiss",
            textColor: Colors.white,
            onPressed: () =>
                rootScaffoldMessengerKey.currentState?.hideCurrentSnackBar(),
          ),
        ),
      );
    };

    _linkSub = _appLinks.uriLinkStream.listen(_handleLink);
  }

  // A smol:// link is the self-certifying form: the §8 strong path,
  // confirmed in the import dialog route before its key is bound. The push
  // waits a frame — the stream can deliver the cold-start link while the
  // first frame is still being laid out.
  void _handleLink(Uri uri) {
    final link = parseSmolLink(uri.toString());
    if (link == null) return;
    if (ref.read(identityProvider) == null) {
      rootScaffoldMessengerKey.currentState?.showSnackBar(
        const SnackBar(
            content: Text("finish onboarding before using smol:// links")),
      );
      return;
    }
    WidgetsBinding.instance.addPostFrameCallback(
      (_) => _router.push(ImportContactDialogRoute(prefill: link.source)),
    );
  }

  @override
  void dispose() {
    _linkSub?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      title: "kirakira",
      theme: appThemeLight,
      darkTheme: appThemeDark,
      themeMode: ThemeMode.system,
      debugShowCheckedModeBanner: false,
      scaffoldMessengerKey: rootScaffoldMessengerKey,
      // smol:// URIs are for app_links, not the route table. The startup link
      // must still resolve to a real route — auto_route throws "Can not
      // resolve initial route" on an unmatched link and leaves a blank
      // screen — so it lands on the normal entry route, whose guard
      // redirects to home exactly like a launcher start. Every later
      // platform link is ignored by the router; the stream handler reacts.
      routerConfig: _router.config(
        deepLinkBuilder: (link) =>
            link.initial ? DeepLink.single(const OnboardingRoute()) : DeepLink.none,
      ),
    );
  }
}