import 'dart:async';

import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import '../../../core/constants/error_whitelist.dart';
import '../../../core/i18n/locale_utils.dart';
import '../../../core/services/auth_proxy_service.dart';
import '../../../core/services/logout_service.dart';
import '../../../core/widgets/theme_toggle_button.dart';
import 'package:userfront/i18n.dart';

class ErrorScreen extends StatefulWidget {
  final String? errorId;
  final String? errorCode;
  final String? description;
  final bool? isProdOverride;
  final Future<Map<String, dynamic>> Function()? sessionProfileLoader;

  const ErrorScreen({
    super.key,
    this.errorId,
    this.errorCode,
    this.description,
    this.isProdOverride,
    this.sessionProfileLoader,
  });

  @override
  State<ErrorScreen> createState() => _ErrorScreenState();
}

class _ErrorScreenState extends State<ErrorScreen> {
  Map<String, dynamic>? _sessionProfile;
  bool _isLoadingSessionProfile = false;
  String? _sessionProfileError;

  bool get _isTenantAccessBlocked =>
      (widget.errorCode ?? '').trim() == 'tenant_not_allowed';

  @override
  void initState() {
    super.initState();
    if (_isTenantAccessBlocked) {
      unawaited(_loadSessionProfile());
    }
  }

  Future<void> _loadSessionProfile() async {
    if (_isLoadingSessionProfile) {
      return;
    }
    setState(() {
      _isLoadingSessionProfile = true;
      _sessionProfileError = null;
    });
    try {
      final loader = widget.sessionProfileLoader ?? AuthProxyService.getMe;
      final profile = await loader();
      if (!mounted) {
        return;
      }
      setState(() {
        _sessionProfile = profile;
      });
    } catch (error) {
      if (!mounted) {
        return;
      }
      setState(() {
        _sessionProfileError = error.toString();
      });
    } finally {
      if (mounted) {
        setState(() {
          _isLoadingSessionProfile = false;
        });
      }
    }
  }

  String _extractTenantLabel(Map<String, dynamic>? profile) {
    if (profile == null) {
      return '';
    }

    final tenant = profile['tenant'];
    if (tenant is Map) {
      final name = tenant['name']?.toString().trim() ?? '';
      if (name.isNotEmpty) {
        return name;
      }
      final slug = tenant['slug']?.toString().trim() ?? '';
      if (slug.isNotEmpty) {
        return slug;
      }
    }

    final joinedTenants = profile['joinedTenants'];
    if (joinedTenants is List) {
      for (final item in joinedTenants) {
        if (item is Map) {
          final name = item['name']?.toString().trim() ?? '';
          if (name.isNotEmpty) {
            return name;
          }
          final slug = item['slug']?.toString().trim() ?? '';
          if (slug.isNotEmpty) {
            return slug;
          }
        }
      }
    }

    final companyCode = profile['companyCode']?.toString().trim() ?? '';
    if (companyCode.isNotEmpty) {
      return companyCode;
    }

    return '';
  }

  Future<void> _switchAccount() async {
    await LogoutService().logout();
    if (!mounted) {
      return;
    }
    context.go(buildLocalizedSigninPath(Uri.base));
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;
    final isProd = widget.isProdOverride ?? AuthProxyService.isProdEnv;
    final normalizedCode = (widget.errorCode ?? '').trim();
    final hasCode = normalizedCode.isNotEmpty;
    final internalWhitelistFallback =
        internalErrorWhitelistMessages[normalizedCode];
    final isInternalWhitelisted = internalWhitelistFallback != null;
    final isOryBypass = hasCode && oryBypassErrorCodes.contains(normalizedCode);
    final isKnownProdCode = hasCode && (isInternalWhitelisted || isOryBypass);
    final isTenantAccessBlocked = normalizedCode == 'tenant_not_allowed';
    final errorType = isProd
        ? (isKnownProdCode ? normalizedCode : 'unknown_error')
        : (hasCode ? normalizedCode : 'unknown_error');
    final title = isProd
        ? tr('msg.userfront.error.title')
        : (hasCode
              ? tr(
                  'msg.userfront.error.title_with_code',
                  params: {'code': normalizedCode},
                )
              : tr('msg.userfront.error.title_generic'));
    final detail = isTenantAccessBlocked
        ? tr(
            'msg.userfront.error.tenant.detail',
            fallback:
                '현재 로그인된 계정은 이 애플리케이션에 접근할 수 없습니다.',
          )
        : isProd
            ? (isInternalWhitelisted
                  ? tr(
                      'msg.userfront.error.whitelist.$normalizedCode',
                      fallback: internalWhitelistFallback,
                    )
                  : (isOryBypass
                        ? tr(
                            'msg.userfront.error.ory.$normalizedCode',
                            fallback: (widget.description?.isNotEmpty == true)
                                ? widget.description
                                : tr('msg.userfront.error.detail_request'),
                          )
                        : tr('msg.userfront.error.detail_contact')))
            : ((widget.description?.isNotEmpty == true)
                  ? widget.description!
                  : (hasCode
                        ? tr('msg.userfront.error.detail_generic')
                        : tr('msg.userfront.error.detail_request')));
    final tenantLabel = _extractTenantLabel(_sessionProfile);
    final emailLabel = _sessionProfile?['email']?.toString().trim() ?? '';

    return Scaffold(
      backgroundColor: colorScheme.surfaceContainerLowest,
      body: SafeArea(
        child: SingleChildScrollView(
          padding: const EdgeInsets.symmetric(vertical: 24),
          child: Center(
            child: ConstrainedBox(
              constraints: const BoxConstraints(maxWidth: 560),
              child: Card(
                margin: const EdgeInsets.symmetric(horizontal: 24),
                elevation: 0,
                shape: RoundedRectangleBorder(
                  borderRadius: BorderRadius.circular(16),
                  side: BorderSide(color: colorScheme.outlineVariant),
                ),
                child: Padding(
                  padding: const EdgeInsets.fromLTRB(28, 28, 28, 24),
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                  Row(
                    children: [
                      Expanded(
                        child: Text(
                          title,
                          style: theme.textTheme.titleLarge?.copyWith(
                            fontWeight: FontWeight.w700,
                            color: colorScheme.onSurface,
                          ),
                        ),
                      ),
                      const ThemeToggleButton(compact: true),
                    ],
                  ),
                  const SizedBox(height: 12),
                  Text(
                    detail,
                    style: theme.textTheme.bodyMedium?.copyWith(
                      color: colorScheme.onSurfaceVariant,
                      height: 1.5,
                    ),
                  ),
                  if (isTenantAccessBlocked) ...[
                    const SizedBox(height: 16),
                    Container(
                      width: double.infinity,
                      padding: const EdgeInsets.all(16),
                      decoration: BoxDecoration(
                        color: colorScheme.surface,
                        borderRadius: BorderRadius.circular(12),
                        border: Border.all(color: colorScheme.outlineVariant),
                      ),
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Text(
                            tr(
                              'msg.userfront.error.tenant.title',
                              fallback: '접근 제한 정보',
                            ),
                            style: theme.textTheme.titleSmall?.copyWith(
                              fontWeight: FontWeight.w700,
                            ),
                          ),
                          const SizedBox(height: 12),
                          if (_isLoadingSessionProfile)
                            Row(
                              crossAxisAlignment: CrossAxisAlignment.start,
                              children: [
                                SizedBox(
                                  width: 16,
                                  height: 16,
                                  child: CircularProgressIndicator(
                                    strokeWidth: 2,
                                    color: colorScheme.primary,
                                  ),
                                ),
                                const SizedBox(width: 10),
                                Flexible(
                                  child: Text(
                                    tr(
                                      'msg.userfront.error.tenant.loading',
                                      fallback:
                                          '현재 계정 정보를 불러오는 중입니다.',
                                    ),
                                    style: theme.textTheme.bodySmall?.copyWith(
                                      color: colorScheme.onSurfaceVariant,
                                    ),
                                  ),
                                ),
                              ],
                            )
                          else ...[
                            _InfoRow(
                              label: tr(
                                'msg.userfront.error.tenant.account',
                                fallback: '계정',
                              ),
                              value: emailLabel.isNotEmpty
                                  ? emailLabel
                                  : tr(
                                      'msg.userfront.error.tenant.account_unknown',
                                      fallback: '알 수 없음',
                                    ),
                            ),
                            const SizedBox(height: 8),
                            _InfoRow(
                              label: tr(
                                'msg.userfront.error.tenant.tenant',
                                fallback: '소속 테넌트',
                              ),
                              value: tenantLabel.isNotEmpty
                                  ? tenantLabel
                                  : tr(
                                      'msg.userfront.error.tenant.tenant_unknown',
                                      fallback: '알 수 없음',
                                    ),
                            ),
                            if (_sessionProfileError != null &&
                                _sessionProfileError!.isNotEmpty) ...[
                              const SizedBox(height: 12),
                              Text(
                                tr(
                                  'msg.userfront.error.tenant.load_failed',
                                  fallback:
                                      '계정 정보를 확인하지 못했습니다. 다시 시도해 주세요.',
                                ),
                                style: theme.textTheme.bodySmall?.copyWith(
                                  color: colorScheme.onSurfaceVariant,
                                ),
                              ),
                            ],
                          ],
                        ],
                      ),
                    ),
                  ],
                  const SizedBox(height: 12),
                  Text(
                    tr('msg.userfront.error.type', params: {'type': errorType}),
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: colorScheme.onSurfaceVariant,
                    ),
                  ),
                  if (widget.errorId != null && widget.errorId!.isNotEmpty) ...[
                    const SizedBox(height: 12),
                    Text(
                      tr('msg.userfront.error.id',
                          params: {'id': widget.errorId!}),
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: colorScheme.onSurfaceVariant,
                      ),
                    ),
                  ],
                  const SizedBox(height: 20),
                  Wrap(
                    spacing: 12,
                    runSpacing: 12,
                    children: [
                      ElevatedButton(
                        onPressed: isTenantAccessBlocked
                            ? _switchAccount
                            : () => context.go('/login'),
                        style: ElevatedButton.styleFrom(
                          backgroundColor: colorScheme.primary,
                          foregroundColor: colorScheme.onPrimary,
                          padding: const EdgeInsets.symmetric(
                            horizontal: 16,
                            vertical: 12,
                          ),
                          shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(10),
                          ),
                        ),
                        child: Text(
                          isTenantAccessBlocked
                              ? tr('ui.userfront.error.switch_account')
                              : tr('ui.userfront.error.go_login'),
                        ),
                      ),
                      OutlinedButton(
                        onPressed: () =>
                            context.go(buildLocalizedHomePath(Uri.base)),
                        style: OutlinedButton.styleFrom(
                          foregroundColor: colorScheme.onSurface,
                          padding: const EdgeInsets.symmetric(
                            horizontal: 16,
                            vertical: 12,
                          ),
                          side: BorderSide(color: colorScheme.outline),
                          shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(10),
                          ),
                        ),
                        child: Text(tr('ui.userfront.error.go_home')),
                      ),
                    ],
                  ),
                    ],
                  ),
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class _InfoRow extends StatelessWidget {
  final String label;
  final String value;

  const _InfoRow({required this.label, required this.value});

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;
    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        SizedBox(
          width: 100,
          child: Text(
            label,
            style: theme.textTheme.bodySmall?.copyWith(
              color: colorScheme.onSurfaceVariant,
              fontWeight: FontWeight.w600,
            ),
          ),
        ),
        Expanded(
          child: Text(
            value,
            style: theme.textTheme.bodySmall?.copyWith(
              color: colorScheme.onSurface,
            ),
          ),
        ),
      ],
    );
  }
}