import 'package:flutter/material.dart';

// Re-defining SidebarItem here for self-containment,
// ideally this would be in a shared utility file if used across many screens.
class SidebarItem {
  final IconData? icon;
  final String label;
  final String? route;
  final List<SidebarItem>? children;
  final bool isParent;
  final String? imagePath;

  const SidebarItem({
    this.icon,
    required this.label,
    this.route,
    this.children,
    this.isParent = false,
    this.imagePath,
  }) : assert(icon != null || imagePath != null, 'Either icon or imagePath must be provided');
}

class RiverHomePage extends StatelessWidget {
  const RiverHomePage({super.key});

  // Define River's sub-menu structure (Manual, Continuous, Investigative)
  final List<SidebarItem> _riverSubMenus = const [
    SidebarItem(
      icon: Icons.handshake,
      label: "Manual",
      isParent: true,
      children: [
        SidebarItem(icon: Icons.dashboard, label: "Dashboard", route: '/river/manual/dashboard'),
        SidebarItem(icon: Icons.pin_drop, label: "In-Situ Sampling", route: '/river/manual/in-situ'),
        SidebarItem(icon: Icons.receipt_long, label: "Report", route: '/river/manual/report'),
        SidebarItem(icon: Icons.date_range, label: "Triennial Sampling", route: '/river/manual/triennial'),
        SidebarItem(icon: Icons.article, label: "Data Log", route: '/river/manual/data-log'),
        SidebarItem(icon: Icons.image, label: "Image Request", route: '/river/manual/image-request'),
      ],
    ),
    SidebarItem(
      icon: Icons.trending_up,
      label: "Continuous",
      isParent: true,
      children: [
        SidebarItem(icon: Icons.dashboard, label: "Dashboard", route: '/river/continuous/dashboard'),
        SidebarItem(icon: Icons.info, label: "Overview", route: '/river/continuous/overview'),
        SidebarItem(icon: Icons.input, label: "Entry", route: '/river/continuous/entry'),
        SidebarItem(icon: Icons.receipt_long, label: "Report", route: '/river/continuous/report'),
      ],
    ),
    SidebarItem(
      icon: Icons.search,
      label: "Investigative",
      isParent: true,
      children: [
        SidebarItem(icon: Icons.dashboard, label: "Dashboard", route: '/river/investigative/dashboard'),
        SidebarItem(icon: Icons.info, label: "Overview", route: '/river/investigative/overview'),
        SidebarItem(icon: Icons.input, label: "Entry", route: '/river/investigative/entry'),
        SidebarItem(icon: Icons.receipt_long, label: "Report", route: '/river/investigative/report'),
      ],
    ),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("River Department"),
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(24.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(
              "Explore River Monitoring Sections",
              style: Theme.of(context).textTheme.headlineSmall?.copyWith(
                fontWeight: FontWeight.bold,
              ),
            ),
            const SizedBox(height: 24),
            Column(
              children: _riverSubMenus.map((category) {
                return _buildCategorySection(context, category);
              }).toList(),
            ),
          ],
        ),
      ),
    );
  }

  // Method to build each category section (Manual, Continuous, Investigative)
  Widget _buildCategorySection(BuildContext context, SidebarItem category) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        // Category header (icon + label)
        Padding(
          padding: const EdgeInsets.symmetric(vertical: 8.0),
          child: Row(
            children: [
              Icon(category.icon, size: 30, color: Theme.of(context).iconTheme.color),
              const SizedBox(width: 12),
              Text(
                category.label,
                style: Theme.of(context).textTheme.titleLarge?.copyWith(
                  fontWeight: FontWeight.bold,
                ),
              ),
            ],
          ),
        ),
        const Divider(height: 24, thickness: 1, color: Colors.white24), // Divider below category title
        // Grid of sub-menu items
        GridView.builder(
          shrinkWrap: true,
          physics: const NeverScrollableScrollPhysics(),
          gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
            crossAxisCount: 3, // 3 columns for sub-menu items
            crossAxisSpacing: 0.0, // Removed horizontal spacing
            mainAxisSpacing: 0.0,  // Removed vertical spacing
            childAspectRatio: 2.8, // Adjusted aspect ratio for horizontal icon-label layout with bigger content
          ),
          itemCount: category.children?.length ?? 0,
          itemBuilder: (context, index) {
            final subItem = category.children![index];
            return InkWell(
              onTap: () {
                if (subItem.route != null) {
                  Navigator.pushNamed(context, subItem.route!);
                }
              },
              borderRadius: BorderRadius.circular(0), // Removed border radius for seamless grid
              child: Padding(
                padding: const EdgeInsets.all(8.0), // Padding around the row content
                child: Row( // Changed from Column to Row
                  mainAxisAlignment: MainAxisAlignment.start, // Align content to start
                  children: [
                    subItem.icon != null
                        ? Icon(subItem.icon, color: Colors.white70, size: 24) // Increased icon size from 22 to 24
                        : const SizedBox.shrink(),
                    const SizedBox(width: 8), // Space between icon and text (horizontal)
                    Expanded( // Allow text to take remaining space
                      child: Text(
                        subItem.label,
                        style: Theme.of(context).textTheme.bodySmall?.copyWith(color: Colors.white70, fontSize: 11), // Increased text size from 10 to 11
                        textAlign: TextAlign.left, // Align text to left
                        overflow: TextOverflow.ellipsis,
                        maxLines: 1, // Single line for label
                      ),
                    ),
                  ],
                ),
              ),
            );
          },
        ),
        const SizedBox(height: 16), // Reduced gap after each category group
      ],
    );
  }
}