import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import 'app_theme.dart';
import 'tp_launch_page.dart';

/// Paint a light first frame before asking plugins to read saved data.
Future<void> launchApplication({
  Future<void>? ready,
  Widget? child,
  Future<Widget> Function()? bootstrap,
  VoidCallback? onHomeReady,
}) async {
  assert(bootstrap != null || (ready != null && child != null));
  // Attach error handling immediately, even if a caller already started work.
  final legacy = bootstrap == null ? _legacyReady(ready!, child!) : null;
  runApp(
    TpStartup(bootstrap: bootstrap ?? () => legacy!, onHomeReady: onHomeReady),
  );
}

Future<Widget> _legacyReady(Future<void> ready, Widget child) async {
  try {
    await ready;
  } catch (_) {
    // AppController exposes failed storage reads through the recovery screen.
  }
  return child;
}

class TpStartup extends StatefulWidget {
  const TpStartup({super.key, required this.bootstrap, this.onHomeReady});
  final Future<Widget> Function() bootstrap;
  final VoidCallback? onHomeReady;
  @override
  State<TpStartup> createState() => _TpStartupState();
}

class _TpStartupState extends State<TpStartup>
    with SingleTickerProviderStateMixin {
  late final _fade =
      AnimationController(
        vsync: this,
        duration: const Duration(milliseconds: 300),
      )..addStatusListener((status) {
        if (status == AnimationStatus.completed && mounted) {
          setState(() => _revealed = true);
        }
      });
  Widget? _home;
  bool _failed = false, _revealed = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) _bootstrap();
    });
  }

  void _bootstrap() {
    setState(() => _failed = false);
    Future<Widget>.sync(widget.bootstrap).then(
      (home) {
        if (!mounted) return;
        setState(() => _home = home);
        // Paint home behind an opaque brand frame before fading it out.
        WidgetsBinding.instance.addPostFrameCallback((_) {
          if (!mounted) return;
          final reduced =
              MediaQuery.maybeOf(context)?.disableAnimations ??
              WidgetsBinding
                  .instance
                  .platformDispatcher
                  .accessibilityFeatures
                  .disableAnimations;
          if (reduced) {
            _fade.value = 1;
          } else {
            _fade.forward();
          }
          widget.onHomeReady?.call();
        });
      },
      onError: (Object error, StackTrace stack) {
        if (mounted) setState(() => _failed = true);
      },
    );
  }

  @override
  void dispose() {
    _fade.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    Widget content = Directionality(
      textDirection: TextDirection.ltr,
      child: Theme(
        data: hepanTheme(),
        child: AnimatedBuilder(
          animation: _fade,
          builder: (context, _) {
            final progress = Curves.easeOutCubic.transform(_fade.value);
            return AnnotatedRegion<SystemUiOverlayStyle>(
              value:
                  (progress < 0.5
                          ? SystemUiOverlayStyle.light
                          : SystemUiOverlayStyle.dark)
                      .copyWith(
                        statusBarColor: Colors.transparent,
                        systemNavigationBarColor: Color.lerp(
                          const Color(0xFF38B3FF),
                          canvas,
                          progress,
                        ),
                      ),
              child: ColoredBox(
                color: const Color(0xFF38B3FF),
                child: Stack(
                  fit: StackFit.expand,
                  children: [
                    if (_home != null)
                      ExcludeSemantics(
                        excluding: !_revealed,
                        child: ExcludeFocus(
                          excluding: !_revealed,
                          child: IgnorePointer(
                            ignoring: !_revealed,
                            child: Transform.translate(
                              offset: Offset(0, 6 * (1 - progress)),
                              child: _home,
                            ),
                          ),
                        ),
                      ),
                    if (!_revealed)
                      IgnorePointer(
                        ignoring: !_failed,
                        child: Opacity(
                          key: const Key('startup-brand-overlay'),
                          opacity: 1 - progress,
                          child: _failed
                              ? _recovery()
                              : const TpLaunchPage(nativeContinuity: true),
                        ),
                      ),
                  ],
                ),
              ),
            );
          },
        ),
      ),
    );
    if (MediaQuery.maybeOf(context) == null) {
      content = MediaQuery.fromView(view: View.of(context), child: content);
    }
    return content;
  }

  Widget _recovery() => Material(
    color: const Color(0xFF38B3FF),
    child: Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Text(
            '启动未完成，请重试',
            style: TextStyle(color: Colors.white, fontSize: 18),
          ),
          const SizedBox(height: 20),
          FilledButton(
            style: FilledButton.styleFrom(
              backgroundColor: Colors.white,
              foregroundColor: river,
            ),
            onPressed: _bootstrap,
            child: const Text('重新打开'),
          ),
        ],
      ),
    ),
  );
}