import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import '../../models/nav_item.dart';

class NavItemTile extends StatelessWidget {
  final NavItem item;
  final String currentRoute;

  const NavItemTile({
    super.key,
    required this.item,
    required this.currentRoute,
  });

  @override
  Widget build(BuildContext context) {
    if (item.hasChildren) {
      return _GroupTile(item: item, currentRoute: currentRoute);
    }
    return _LeafTile(item: item, currentRoute: currentRoute);
  }
}

// ── Leaf (item sin hijos) ──────────────────────────────────────────────────

class _LeafTile extends StatelessWidget {
  final NavItem item;
  final String currentRoute;

  const _LeafTile({required this.item, required this.currentRoute});

  bool get _isActive =>
      item.route != null && currentRoute == item.route;

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

    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 1),
      child: Material(
        color: _isActive ? cs.secondaryContainer : Colors.transparent,
        borderRadius: BorderRadius.circular(12),
        child: InkWell(
          borderRadius: BorderRadius.circular(12),
          onTap: () => context.go(item.route!),
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
            child: Row(
              children: [
                Icon(
                  item.icon,
                  size: 20,
                  color: _isActive ? cs.onSecondaryContainer : cs.onSurfaceVariant,
                ),
                const SizedBox(width: 12),
                Expanded(
                  child: Text(
                    item.label,
                    style: tt.bodyMedium?.copyWith(
                      color: _isActive ? cs.onSecondaryContainer : cs.onSurface,
                      fontWeight: _isActive ? FontWeight.w600 : FontWeight.normal,
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

// ── Group (item con hijos, expansible) ────────────────────────────────────

class _GroupTile extends StatefulWidget {
  final NavItem item;
  final String currentRoute;

  const _GroupTile({required this.item, required this.currentRoute});

  @override
  State<_GroupTile> createState() => _GroupTileState();
}

class _GroupTileState extends State<_GroupTile> {
  late bool _expanded;

  @override
  void initState() {
    super.initState();
    _expanded = widget.item.isActiveOrAncestor(widget.currentRoute);
  }

  @override
  void didUpdateWidget(_GroupTile old) {
    super.didUpdateWidget(old);
    if (old.currentRoute != widget.currentRoute) {
      if (widget.item.isActiveOrAncestor(widget.currentRoute)) {
        _expanded = true;
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final cs = Theme.of(context).colorScheme;
    final tt = Theme.of(context).textTheme;
    final isAncestor = widget.item.isActiveOrAncestor(widget.currentRoute);

    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 1),
      child: Theme(
        // Quita el separador por defecto del ExpansionTile
        data: Theme.of(context).copyWith(dividerColor: Colors.transparent),
        child: ExpansionTile(
          initiallyExpanded: _expanded,
          onExpansionChanged: (v) => setState(() => _expanded = v),
          tilePadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 0),
          childrenPadding: const EdgeInsets.only(left: 16),
          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
          collapsedShape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
          backgroundColor: isAncestor ? cs.surfaceContainerHigh : Colors.transparent,
          collapsedBackgroundColor: Colors.transparent,
          leading: Icon(
            widget.item.icon,
            size: 20,
            color: isAncestor ? cs.primary : cs.onSurfaceVariant,
          ),
          title: Text(
            widget.item.label,
            style: tt.bodyMedium?.copyWith(
              color: isAncestor ? cs.primary : cs.onSurface,
              fontWeight: isAncestor ? FontWeight.w600 : FontWeight.normal,
            ),
          ),
          children: widget.item.children
              .map((child) => NavItemTile(
                    item: child,
                    currentRoute: widget.currentRoute,
                  ))
              .toList(),
        ),
      ),
    );
  }
}