import 'dart:async';

import 'package:flutter/material.dart';

// When a deep link is triggered while the app is closed we first need to load the app so we save it here to handle later.
String? globalPendingDeepLink;

Future<void> main() async {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  bool loading = true;

  @override
  void initState() {
    super.initState();
    // Mock initial app loading. Deep links would be handled after the app loads.
    Future.delayed(Duration(seconds: 3)).then((_) {
      if (!mounted) return;
      setState(() {
        loading = false;
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      onGenerateRoute: createOnGenerateRoute(),
      onGenerateInitialRoutes: (route) {
        print("FLUTTER: onGenerateInitialRoutes: $route");

        return [
          MaterialPageRoute(
            builder: (context) {
              return HomeWidget(appLoading: loading);
            },
          ),
        ];
      },
    );
  }

  RouteFactory createOnGenerateRoute() {
    return (RouteSettings settings) {
      final pathOrUri = settings.name;
      print("FLUTTER: onGenerateRoute: $pathOrUri initial app loading: $loading");
      if (loading) {
        // Save link until the app is loaded to handle later.
        globalPendingDeepLink = pathOrUri;
        return null;
      }

      final route = _handleRouteSettings(pathOrUri);
      if (route != null) {
        return route;
      }

      return null;
    };
  }
}

class HomeWidget extends StatefulWidget {
  final bool appLoading;
  const HomeWidget({super.key, required this.appLoading});

  @override
  State<HomeWidget> createState() => HomeWidgetState();
}

class HomeWidgetState extends State<HomeWidget> {
  @override
  void didUpdateWidget(covariant HomeWidget oldWidget) {
    if (widget.appLoading != oldWidget.appLoading && !widget.appLoading) {
      print("FLUTTER: app has been loaded. Pending link $globalPendingDeepLink");
      WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
        if (globalPendingDeepLink != null) {
          final route = _handleRouteSettings(globalPendingDeepLink);
          if (route != null) {
            globalPendingDeepLink = null;
            Navigator.of(context, rootNavigator: true).push<void>(route);
          }
        }
      });
    }
    ;
    super.didUpdateWidget(oldWidget);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("Home")),
      body: Center(child: widget.appLoading ? CircularProgressIndicator() : Text("Home")),
    );
  }
}

Route<Object?>? _handleRouteSettings(String? pathOrUri) {
  print("HANDLE ROUTE SETTINGS: $pathOrUri");
  if (pathOrUri == null || pathOrUri == "/") {
    return null;
  }

  return MaterialPageRoute(
    builder: (context) => Scaffold(
      appBar: AppBar(),
      body: Center(child: Text("Deep link: $pathOrUri")),
    ),
  );
}