import 'package:auto_route/auto_route.dart';
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:trainhub_flutter/core/constants/ui_constants.dart';
import 'package:trainhub_flutter/core/router/app_router.dart';
import 'package:trainhub_flutter/core/theme/app_colors.dart';

@RoutePage()
class ShellPage extends StatelessWidget {
  const ShellPage({super.key});

  @override
  Widget build(BuildContext context) {
    return AutoTabsRouter(
      routes: const [
        HomeRoute(),
        TrainingsRoute(),
        AnalysisRoute(),
        CalendarRoute(),
        ChatRoute(),
      ],
      builder: (context, child) {
        final tabsRouter = AutoTabsRouter.of(context);
        return Scaffold(
          body: Row(
            children: [
              _Sidebar(
                activeIndex: tabsRouter.activeIndex,
                onDestinationSelected: tabsRouter.setActiveIndex,
              ),
              Expanded(child: child),
            ],
          ),
        );
      },
    );
  }
}

// ---------------------------------------------------------------------------
// Sidebar
// ---------------------------------------------------------------------------

class _NavItemData {
  final IconData icon;
  final IconData activeIcon;
  final String label;

  const _NavItemData({
    required this.icon,
    required this.activeIcon,
    required this.label,
  });
}

class _Sidebar extends StatelessWidget {
  final int activeIndex;
  final ValueChanged<int> onDestinationSelected;

  const _Sidebar({
    required this.activeIndex,
    required this.onDestinationSelected,
  });

  static const _items = [
    _NavItemData(
      icon: Icons.dashboard_outlined,
      activeIcon: Icons.dashboard_rounded,
      label: 'Home',
    ),
    _NavItemData(
      icon: Icons.fitness_center_outlined,
      activeIcon: Icons.fitness_center,
      label: 'Trainings',
    ),
    _NavItemData(
      icon: Icons.video_library_outlined,
      activeIcon: Icons.video_library,
      label: 'Analysis',
    ),
    _NavItemData(
      icon: Icons.calendar_today_outlined,
      activeIcon: Icons.calendar_today,
      label: 'Calendar',
    ),
    _NavItemData(
      icon: Icons.chat_bubble_outline,
      activeIcon: Icons.chat_bubble,
      label: 'AI Chat',
    ),
  ];

  @override
  Widget build(BuildContext context) {
    return Container(
      width: 200,
      decoration: const BoxDecoration(
        color: AppColors.surfaceContainer,
        border: Border(right: BorderSide(color: AppColors.border)),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          // --- Logo ---
          Padding(
            padding: const EdgeInsets.fromLTRB(16, 20, 16, 20),
            child: Row(
              children: [
                Container(
                  width: 34,
                  height: 34,
                  decoration: BoxDecoration(
                    color: AppColors.accentMuted,
                    borderRadius: BorderRadius.circular(8),
                  ),
                  child: const Icon(
                    Icons.fitness_center,
                    color: AppColors.accent,
                    size: 18,
                  ),
                ),
                const SizedBox(width: 10),
                Text(
                  'TrainHub',
                  style: GoogleFonts.inter(
                    fontSize: 15,
                    fontWeight: FontWeight.w700,
                    color: AppColors.textPrimary,
                    letterSpacing: -0.3,
                  ),
                ),
              ],
            ),
          ),

          const Padding(
            padding: EdgeInsets.symmetric(horizontal: 12),
            child: Divider(height: 1),
          ),
          const SizedBox(height: UIConstants.spacing8),

          // --- Nav items ---
          for (int i = 0; i < _items.length; i++)
            _NavItem(
              data: _items[i],
              isActive: activeIndex == i,
              onTap: () => onDestinationSelected(i),
            ),

          const Spacer(),

          // --- Footer ---
          Padding(
            padding: const EdgeInsets.fromLTRB(12, 8, 12, 12),
            child: Row(
              children: [
                Text(
                  'v2.0.0',
                  style: GoogleFonts.inter(
                    fontSize: 11,
                    color: AppColors.textMuted,
                  ),
                ),
                const Spacer(),
                const _SettingsButton(),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

class _NavItem extends StatefulWidget {
  final _NavItemData data;
  final bool isActive;
  final VoidCallback onTap;

  const _NavItem({
    required this.data,
    required this.isActive,
    required this.onTap,
  });

  @override
  State<_NavItem> createState() => _NavItemState();
}

class _NavItemState extends State<_NavItem> {
  bool _isHovered = false;

  @override
  Widget build(BuildContext context) {
    final active = widget.isActive;

    return MouseRegion(
      onEnter: (_) => setState(() => _isHovered = true),
      onExit: (_) => setState(() => _isHovered = false),
      child: GestureDetector(
        onTap: widget.onTap,
        child: AnimatedContainer(
          duration: UIConstants.animationDuration,
          height: 40,
          margin: const EdgeInsets.symmetric(horizontal: 8, vertical: 1),
          decoration: BoxDecoration(
            color: active
                ? AppColors.zinc800
                : _isHovered
                    ? AppColors.zinc900
                    : Colors.transparent,
            borderRadius: BorderRadius.circular(6),
          ),
          child: Row(
            children: [
              // Left accent indicator
              AnimatedContainer(
                duration: UIConstants.animationDuration,
                width: 3,
                height: active ? 20 : 0,
                margin: const EdgeInsets.only(left: 4, right: 8),
                decoration: BoxDecoration(
                  color: AppColors.accent,
                  borderRadius: BorderRadius.circular(2),
                ),
              ),
              if (!active) const SizedBox(width: 15),
              Icon(
                active ? widget.data.activeIcon : widget.data.icon,
                size: 17,
                color: active ? AppColors.textPrimary : AppColors.textMuted,
              ),
              const SizedBox(width: 9),
              Text(
                widget.data.label,
                style: GoogleFonts.inter(
                  fontSize: 13,
                  fontWeight: active ? FontWeight.w600 : FontWeight.w400,
                  color: active
                      ? AppColors.textPrimary
                      : _isHovered
                          ? AppColors.textSecondary
                          : AppColors.textMuted,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

// ---------------------------------------------------------------------------
// Settings icon button in sidebar footer
// ---------------------------------------------------------------------------
class _SettingsButton extends StatefulWidget {
  const _SettingsButton();

  @override
  State<_SettingsButton> createState() => _SettingsButtonState();
}

class _SettingsButtonState extends State<_SettingsButton> {
  bool _hovered = false;

  @override
  Widget build(BuildContext context) {
    return Tooltip(
      message: 'Settings',
      child: MouseRegion(
        onEnter: (_) => setState(() => _hovered = true),
        onExit: (_) => setState(() => _hovered = false),
        child: GestureDetector(
          onTap: () => context.router.push(const SettingsRoute()),
          child: AnimatedContainer(
            duration: UIConstants.animationDuration,
            width: 28,
            height: 28,
            decoration: BoxDecoration(
              color: _hovered ? AppColors.zinc800 : Colors.transparent,
              borderRadius: BorderRadius.circular(6),
            ),
            child: Icon(
              Icons.settings_outlined,
              size: 16,
              color: _hovered ? AppColors.textSecondary : AppColors.textMuted,
            ),
          ),
        ),
      ),
    );
  }
}