import 'package:flutter/material.dart';
import 'package:get_it/get_it.dart';
import 'package:go_router/go_router.dart';
import 'package:intl/intl.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart' as lucide;
import 'package:shadcn_ui/shadcn_ui.dart';

import '../core/constants/app_sections.dart';
import '../core/permissions/permission_manager.dart';
import '../core/theme/theme_controller.dart';
import '../features/auth/application/auth_service.dart';
import '../features/auth/domain/entities/auth_session.dart';
import 'components/superport_dialog.dart';

/// 앱 기본 레이아웃을 제공하는 셸 위젯. 사이드 네비게이션과 AppBar를 구성한다.
class AppShell extends StatelessWidget {
  const AppShell({
    super.key,
    required this.child,
    required this.currentLocation,
  });

  final Widget child;
  final String currentLocation;

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        final isWide = constraints.maxWidth >= 960;
        final manager = PermissionScope.of(context);
        final filteredPages = <AppPageDescriptor>[
          for (final section in appSections)
            for (final page in section.pages)
              if (manager.can(page.path, PermissionAction.view)) page,
        ];
        final pages = filteredPages.isEmpty ? allAppPages : filteredPages;
        final themeController = ThemeControllerScope.of(context);
        final authService = GetIt.I<AuthService>();
        final appBar = _GradientAppBar(
          title: const _BrandTitle(),
          actions: [
            _ThemeMenuButton(
              mode: themeController.mode,
              onChanged: themeController.update,
            ),
            const SizedBox(width: 8),
            _AccountMenuButton(service: authService),
            const SizedBox(width: 8),
          ],
        );

        if (isWide) {
          return Scaffold(
            appBar: appBar,
            body: Row(
              children: [
                _NavigationRail(currentLocation: currentLocation, pages: pages),
                const VerticalDivider(width: 1),
                Expanded(child: child),
              ],
            ),
          );
        }

        return Scaffold(
          appBar: appBar,
          drawer: Drawer(
            child: SafeArea(
              child: _NavigationList(
                currentLocation: currentLocation,
                onTap: (path) {
                  Navigator.of(context).pop();
                  context.go(path);
                },
                pages: pages,
              ),
            ),
          ),
          body: child,
        );
      },
    );
  }
}

class _NavigationRail extends StatelessWidget {
  const _NavigationRail({required this.currentLocation, required this.pages});

  final String currentLocation;
  final List<AppPageDescriptor> pages;

  @override
  Widget build(BuildContext context) {
    final selectedIndex = _selectedIndex(currentLocation, pages);
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;

    return Container(
      width: 220,
      decoration: BoxDecoration(
        border: Border(right: BorderSide(color: colorScheme.outlineVariant)),
      ),
      child: Column(
        children: [
          const SizedBox(height: 24),
          Expanded(
            child: ListView.builder(
              padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
              itemCount: pages.length,
              itemBuilder: (context, index) {
                final page = pages[index];
                final isSelected = index == selectedIndex;
                final textStyle = theme.textTheme.labelSmall?.copyWith(
                  color: isSelected
                      ? colorScheme.primary
                      : colorScheme.onSurfaceVariant,
                );

                return Padding(
                  padding: const EdgeInsets.symmetric(vertical: 4),
                  child: Material(
                    color: isSelected
                        ? colorScheme.primary.withValues(alpha: 0.12)
                        : Colors.transparent,
                    borderRadius: BorderRadius.circular(12),
                    child: InkWell(
                      borderRadius: BorderRadius.circular(12),
                      onTap: () {
                        if (page.path != currentLocation) {
                          context.go(page.path);
                        }
                      },
                      child: Padding(
                        padding: const EdgeInsets.symmetric(
                          vertical: 10,
                          horizontal: 12,
                        ),
                        child: Row(
                          children: [
                            Icon(
                              page.icon,
                              size: 22,
                              color: isSelected
                                  ? colorScheme.primary
                                  : colorScheme.onSurfaceVariant,
                            ),
                            const SizedBox(width: 12),
                            Expanded(
                              child: Text(
                                page.label,
                                maxLines: 1,
                                overflow: TextOverflow.ellipsis,
                                style: textStyle,
                              ),
                            ),
                          ],
                        ),
                      ),
                    ),
                  ),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}

class _NavigationList extends StatelessWidget {
  const _NavigationList({
    required this.currentLocation,
    required this.onTap,
    required this.pages,
  });

  final String currentLocation;
  final ValueChanged<String> onTap;
  final List<AppPageDescriptor> pages;

  @override
  Widget build(BuildContext context) {
    final selectedIndex = _selectedIndex(currentLocation, pages);
    final themeController = ThemeControllerScope.of(context);

    return ListView.builder(
      itemCount: pages.length + 1,
      itemBuilder: (context, index) {
        if (index == pages.length) {
          return Padding(
            padding: const EdgeInsets.fromLTRB(16, 12, 16, 16),
            child: _ThemeMenuButton(
              mode: themeController.mode,
              onChanged: (mode) {
                themeController.update(mode);
                Navigator.of(context).maybePop();
              },
            ),
          );
        }

        final page = pages[index];
        final selected = index == selectedIndex;
        return ListTile(
          leading: Icon(page.icon),
          title: Text(page.label),
          subtitle: Text(
            page.summary,
            maxLines: 1,
            overflow: TextOverflow.ellipsis,
          ),
          selected: selected,
          selectedColor: Theme.of(context).colorScheme.primary,
          onTap: () => onTap(page.path),
        );
      },
    );
  }
}

class _BrandTitle extends StatelessWidget {
  const _BrandTitle();

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;

    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        DecoratedBox(
          decoration: BoxDecoration(
            shape: BoxShape.circle,
            color: colorScheme.primary,
          ),
          child: Padding(
            padding: const EdgeInsets.all(12),
            child: Icon(
              lucide.LucideIcons.ship,
              size: 28,
              color: colorScheme.onPrimary,
            ),
          ),
        ),
        const SizedBox(width: 12),
        Text(
          'Superport v2',
          style: theme.textTheme.titleLarge?.copyWith(
            fontWeight: FontWeight.w600,
          ),
        ),
      ],
    );
  }
}

class _GradientAppBar extends StatelessWidget implements PreferredSizeWidget {
  const _GradientAppBar({required this.title, required this.actions});

  final Widget title;
  final List<Widget> actions;

  @override
  Size get preferredSize => const Size.fromHeight(kToolbarHeight);

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;

    return AppBar(
      backgroundColor: Colors.transparent,
      surfaceTintColor: Colors.transparent,
      automaticallyImplyLeading: false,
      titleSpacing: 16,
      toolbarHeight: kToolbarHeight,
      title: title,
      actions: actions,
      flexibleSpace: Container(
        decoration: BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.bottomCenter,
            end: Alignment.topCenter,
            colors: [
              colorScheme.primary.withValues(alpha: 0),
              colorScheme.primary.withValues(alpha: 0.2),
            ],
            stops: const [0, 1],
          ),
        ),
      ),
    );
  }
}

class _ThemeMenuButton extends StatelessWidget {
  const _ThemeMenuButton({required this.mode, required this.onChanged});

  final ThemeMode mode;
  final ValueChanged<ThemeMode> onChanged;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;
    final label = _label(mode);
    final icon = _icon(mode);

    return PopupMenuButton<ThemeMode>(
      tooltip: '테마 변경',
      onSelected: onChanged,
      itemBuilder: (context) => ThemeMode.values
          .map(
            (value) => PopupMenuItem<ThemeMode>(
              value: value,
              child: Row(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Icon(_icon(value), size: 18),
                  const SizedBox(width: 8),
                  Flexible(
                    child: Text(
                      _label(value),
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                    ),
                  ),
                ],
              ),
            ),
          )
          .toList(),
      child: Container(
        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(12),
          border: Border.all(color: colorScheme.outlineVariant),
        ),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(icon, size: 18),
            const SizedBox(width: 8),
            Flexible(
              child: Text(
                '테마 · $label',
                style: theme.textTheme.labelSmall,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
              ),
            ),
          ],
        ),
      ),
    );
  }

  static String _label(ThemeMode mode) {
    switch (mode) {
      case ThemeMode.system:
        return '시스템';
      case ThemeMode.light:
        return '라이트';
      case ThemeMode.dark:
        return '다크';
    }
  }

  static IconData _icon(ThemeMode mode) {
    switch (mode) {
      case ThemeMode.system:
        return lucide.LucideIcons.monitorCog;
      case ThemeMode.light:
        return lucide.LucideIcons.sun;
      case ThemeMode.dark:
        return lucide.LucideIcons.moon;
    }
  }
}

int _selectedIndex(String location, List<AppPageDescriptor> pages) {
  final normalized = location.toLowerCase();
  final exact = pages.indexWhere(
    (page) => normalized == page.path.toLowerCase(),
  );
  if (exact != -1) {
    return exact;
  }

  final prefix = pages.indexWhere(
    (page) => normalized.startsWith(page.path.toLowerCase()),
  );
  return prefix == -1 ? 0 : prefix;
}

/// 계정 정보를 확인하고 로그아웃을 수행하는 상단바 버튼.
class _AccountMenuButton extends StatelessWidget {
  const _AccountMenuButton({required this.service});

  final AuthService service;

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      animation: service,
      builder: (context, _) {
        final session = service.session;
        return IconButton(
          tooltip: '계정 정보',
          icon: const Icon(lucide.LucideIcons.userRound),
          onPressed: () => _handlePressed(context, session),
        );
      },
    );
  }

  Future<void> _handlePressed(
    BuildContext context,
    AuthSession? session,
  ) async {
    final shouldLogout = await SuperportDialog.show<bool>(
      context: context,
      dialog: SuperportDialog(
        title: '계정 정보',
        description: session == null
            ? '로그인 정보를 찾을 수 없습니다.'
            : '현재 로그인된 계정 세부 정보를 확인하세요.',
        child: _AccountInfoContent(session: session),
        footer: Builder(
          builder: (dialogContext) {
            return Padding(
              padding: const EdgeInsets.fromLTRB(20, 16, 20, 20),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  ShadButton.outline(
                    onPressed: () => Navigator.of(dialogContext).pop(false),
                    child: const Text('닫기'),
                  ),
                  const SizedBox(width: 12),
                  ShadButton.destructive(
                    onPressed: session == null
                        ? null
                        : () => Navigator.of(dialogContext).pop(true),
                    child: const Text('로그아웃'),
                  ),
                ],
              ),
            );
          },
        ),
        scrollable: session != null && session.permissions.length > 6,
      ),
    );
    if (shouldLogout == true) {
      await service.clearSession();
      if (!context.mounted) return;
      context.go(loginRoutePath);
    }
  }
}

/// 로그인된 계정의 핵심 정보를 보여주는 다이얼로그 본문.
class _AccountInfoContent extends StatelessWidget {
  const _AccountInfoContent({required this.session});

  final AuthSession? session;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;

    if (session == null) {
      return Padding(
        padding: const EdgeInsets.symmetric(vertical: 24),
        child: Text(
          '로그인된 사용자 정보를 불러오지 못했습니다. 다시 로그인하면 세션이 갱신됩니다.',
          style: theme.textTheme.bodyMedium?.copyWith(color: colorScheme.error),
        ),
      );
    }

    final user = session!.user;
    final expiryLabel = _formatExpiry(session!.expiresAt);
    final permissionSummaries = _PermissionSummary.build(session!);

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      mainAxisSize: MainAxisSize.min,
      children: [
        _AccountInfoRow(label: '이름', value: user.name),
        _AccountInfoRow(label: '사번', value: user.employeeNo ?? '-'),
        _AccountInfoRow(label: '이메일', value: user.email ?? '-'),
        _AccountInfoRow(label: '기본 그룹', value: user.primaryGroupName ?? '-'),
        _AccountInfoRow(label: '토큰 만료', value: expiryLabel),
        _AccountInfoRow(
          label: '권한 리소스',
          value: '${permissionSummaries.length}개',
        ),
        if (permissionSummaries.isNotEmpty) ...[
          const SizedBox(height: 16),
          Text(
            '권한 요약',
            style: theme.textTheme.titleSmall?.copyWith(
              fontWeight: FontWeight.w600,
            ),
          ),
          const SizedBox(height: 8),
          Wrap(
            spacing: 8,
            runSpacing: 8,
            children: [
              for (final summary in permissionSummaries.take(6))
                ShadBadge.outline(
                  child: Text(
                    '${summary.resource} · ${_formatActions(summary.actions)}',
                  ),
                ),
              if (permissionSummaries.length > 6)
                ShadBadge.outline(
                  child: Text('외 ${permissionSummaries.length - 6}개 리소스'),
                ),
            ],
          ),
        ],
      ],
    );
  }

  String _formatExpiry(DateTime? expiresAt) {
    if (expiresAt == null) {
      return '만료 정보 없음';
    }
    final formatter = DateFormat('yyyy-MM-dd HH:mm');
    return formatter.format(expiresAt.toLocal());
  }
}

/// 다이얼로그에서 라벨과 값을 한 줄로 표시한다.
class _AccountInfoRow extends StatelessWidget {
  const _AccountInfoRow({required this.label, required this.value});

  final String label;
  final String value;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;

    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 6),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(
            width: 112,
            child: Text(
              label,
              style: theme.textTheme.bodySmall?.copyWith(
                fontWeight: FontWeight.w600,
                color: colorScheme.onSurfaceVariant,
              ),
            ),
          ),
          Expanded(
            child: Text(
              value.isEmpty ? '-' : value,
              style: theme.textTheme.bodyMedium,
            ),
          ),
        ],
      ),
    );
  }
}

/// 리소스별 권한 액션 목록 요약 데이터.
class _PermissionSummary {
  const _PermissionSummary({required this.resource, required this.actions});

  final String resource;
  final List<String> actions;

  static List<_PermissionSummary> build(AuthSession session) {
    final Map<String, Set<String>> aggregated = {};
    for (final permission in session.permissions) {
      final bucket = aggregated.putIfAbsent(
        permission.resource,
        () => <String>{},
      );
      for (final raw in permission.actions) {
        final normalized = raw.trim().toLowerCase();
        if (normalized.isEmpty) continue;
        bucket.add(normalized);
      }
    }
    final summaries =
        aggregated.entries
            .map(
              (entry) => _PermissionSummary(
                resource: entry.key,
                actions: entry.value.toList()..sort(),
              ),
            )
            .toList()
          ..sort((a, b) => a.resource.compareTo(b.resource));
    return summaries;
  }
}

String _formatActions(List<String> actions) {
  if (actions.isEmpty) {
    return '권한 없음';
  }
  final labels = actions.map(_koreanActionLabel).toList()..sort();
  return labels.join(', ');
}

String _koreanActionLabel(String action) {
  return switch (action.trim().toLowerCase()) {
    'view' => '조회',
    'read' => '조회',
    'create' => '생성',
    'edit' => '수정',
    'update' => '수정',
    'delete' => '삭제',
    'restore' => '복구',
    'approve' => '결재',
    _ => action,
  };
}