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

import '../core/constants/app_sections.dart';
import '../core/theme/theme_controller.dart';
import '../core/permissions/permission_manager.dart';

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;
        if (isWide) {
          return Scaffold(
            appBar: AppBar(
              title: const Text('Superport v2'),
              actions: [
                IconButton(
                  tooltip: '로그아웃',
                  icon: const Icon(lucide.LucideIcons.logOut),
                  onPressed: () => context.go(loginRoutePath),
                ),
              ],
            ),
            body: Row(
              children: [
                _NavigationRail(currentLocation: currentLocation, pages: pages),
                const VerticalDivider(width: 1),
                Expanded(child: child),
              ],
            ),
          );
        }

        return Scaffold(
          appBar: AppBar(
            title: const Text('Superport v2'),
            actions: [
              IconButton(
                tooltip: '로그아웃',
                icon: const Icon(lucide.LucideIcons.logOut),
                onPressed: () => context.go(loginRoutePath),
              ),
            ],
          ),
          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;
    final themeController = ThemeControllerScope.of(context);
    final currentThemeMode = themeController.mode;

    return Container(
      width: 104,
      decoration: BoxDecoration(
        border: Border(right: BorderSide(color: colorScheme.outlineVariant)),
      ),
      child: Column(
        children: [
          const SizedBox(height: 24),
          const FlutterLogo(size: 48),
          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: 12,
                          horizontal: 8,
                        ),
                        child: Column(
                          mainAxisSize: MainAxisSize.min,
                          children: [
                            Icon(
                              page.icon,
                              size: 22,
                              color: isSelected
                                  ? colorScheme.primary
                                  : colorScheme.onSurfaceVariant,
                            ),
                            const SizedBox(height: 6),
                            Text(
                              page.label,
                              textAlign: TextAlign.center,
                              maxLines: 2,
                              overflow: TextOverflow.ellipsis,
                              style: textStyle,
                            ),
                          ],
                        ),
                      ),
                    ),
                  ),
                );
              },
            ),
          ),
          Padding(
            padding: const EdgeInsets.fromLTRB(12, 8, 12, 16),
            child: _ThemeMenuButton(
              mode: currentThemeMode,
              onChanged: themeController.update,
            ),
          ),
        ],
      ),
    );
  }
}

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 _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(
                children: [
                  Icon(_icon(value), size: 18),
                  const SizedBox(width: 8),
                  Text(_label(value)),
                ],
              ),
            ),
          )
          .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,
          children: [
            Icon(icon, size: 18),
            const SizedBox(width: 8),
            Text('테마 · $label', style: theme.textTheme.labelSmall),
          ],
        ),
      ),
    );
  }

  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;
}