import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import '../../../core/api/api_client_provider.dart';
import '../../../core/auth/auth_notifier.dart';
import '../../../core/theme/halo_tokens.dart';
import '../../../core/theme/widgets/widgets.dart';
import '../widgets/verif_choice_sheet.dart';

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

  @override
  ConsumerState<DisplayNameScreen> createState() => _DisplayNameScreenState();
}

class _DisplayNameScreenState extends ConsumerState<DisplayNameScreen> {
  final _controller = TextEditingController();
  ProviderSubscription<AsyncValue<AuthData>>? _authSub;
  String? _errorMessage;
  bool _routedAfterLogin = false;

  @override
  void initState() {
    super.initState();
    // Listener registered once in initState (see feedback_riverpod_listen_in_build).
    // We need to react to auth state changes once the anonymous login resolves
    // to drive the post-name onboarding fork.
    _authSub = ref.listenManual<AsyncValue<AuthData>>(authProvider, (prev, next) {
      if (!mounted) return;
      if (next is AsyncError) {
        setState(() => _errorMessage = next.error.toString());
        return;
      }
      final data = next.valueOrNull;
      if (data is AuthAnonymousData && !_routedAfterLogin) {
        _routedAfterLogin = true;
        _proceedAfterLogin();
      }
    });
  }

  @override
  void dispose() {
    _authSub?.close();
    _controller.dispose();
    super.dispose();
  }

  void _submit() {
    final name = _controller.text.trim();
    if (name.isEmpty) return;
    setState(() => _errorMessage = null);
    ref.read(authProvider.notifier).loginAnonymous(name);
  }

  /// After an anonymous login succeeds, decide where to send the user.
  ///
  /// 1. Read `/api/client/onboarding-state`. If `has_consulted_before`, the
  ///    user is a returning customer — skip the onboarding sequence and
  ///    jump straight to the duration picker (Stage 3 owns that route).
  /// 2. Otherwise show the Verif Choice Sheet and route based on the picked
  ///    branch.
  Future<void> _proceedAfterLogin() async {
    bool hasConsultedBefore = false;
    try {
      final response =
          await ref.read(apiClientProvider).get('/api/client/onboarding-state');
      final data = response['data'] as Map<String, dynamic>?;
      hasConsultedBefore =
          (data?['has_consulted_before'] as bool?) ?? false;
    } catch (_) {
      // Treat as first-time on failure — safer to over-collect onboarding
      // info than to silently strand a returning user.
    }
    if (!mounted) return;

    if (hasConsultedBefore) {
      // TODO(stage3): Stage 3 will own /payment/duration-pick — for now
      // route there as a placeholder so returning users can continue.
      context.go('/payment/duration-pick');
      return;
    }

    final choice = await VerifChoiceSheet.show(context);
    if (!mounted || choice == null) {
      // User dismissed the sheet — let them tap Lanjut again to retry.
      _routedAfterLogin = false;
      return;
    }
    if (!mounted) return;
    await routeForVerifChoice(context, ref, choice);
  }

  @override
  Widget build(BuildContext context) {
    final authState = ref.watch(authProvider);
    final isLoading = authState is AsyncLoading;

    return Scaffold(
      appBar: AppBar(title: const Text('Siapa namamu?')),
      body: SafeArea(
        child: Padding(
          padding: const EdgeInsets.all(HaloSpacing.s24),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              const Text(
                'Pilih nama yang ingin kamu gunakan. Nama ini akan terlihat oleh bestie kamu.',
                style: TextStyle(
                  fontFamily: HaloTokens.fontBody,
                  fontSize: 15,
                  height: 22 / 15,
                  color: HaloTokens.inkSoft,
                ),
              ),
              const SizedBox(height: HaloSpacing.s24),
              TextField(
                controller: _controller,
                decoration: const InputDecoration(
                  labelText: 'Nama panggilan',
                ),
                textInputAction: TextInputAction.done,
                onSubmitted: (_) => _submit(),
              ),
              if (_errorMessage != null) ...[
                const SizedBox(height: HaloSpacing.s12),
                Text(
                  _errorMessage!,
                  textAlign: TextAlign.center,
                  style: const TextStyle(
                    fontFamily: HaloTokens.fontBody,
                    color: HaloTokens.danger,
                    fontSize: 13,
                  ),
                ),
              ],
              const SizedBox(height: HaloSpacing.s24),
              HaloButton(
                label: isLoading ? 'memproses...' : 'lanjut',
                fullWidth: true,
                onPressed: isLoading ? null : _submit,
              ),
            ],
          ),
        ),
      ),
    );
  }
}