import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../../core/ui/async_state_views.dart';
import '../data/inventory_providers.dart';
import '../domain/inventory_item.dart';

class InventoryScreen extends ConsumerWidget {
  const InventoryScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final inventoryAsync = ref.watch(inventoryProvider);

    return inventoryAsync.when(
      loading: () => const LoadingStateView(label: 'Laddar inventarie...'),
      error: (e, _) => ErrorStateView(
        message: e.toString(),
        onRetry: () => ref.invalidate(inventoryProvider),
      ),
      data: (items) {
        if (items.isEmpty) {
          return EmptyStateView(
            message: 'Inventariet är tomt.',
            action: FloatingActionButton.extended(
              onPressed: () => context.push('/inventory/create'),
              icon: const Icon(Icons.add),
              label: const Text('Lägg till'),
            ),
          );
        }
        return Stack(
          children: [
            ListView.separated(
              padding: const EdgeInsets.only(bottom: 88),
              itemCount: items.length,
              separatorBuilder: (_, __) => const Divider(height: 1),
              itemBuilder: (context, index) {
                final item = items[index];
                return _InventoryTile(item: item);
              },
            ),
            Positioned(
              right: 16,
              bottom: 16,
              child: FloatingActionButton.extended(
                onPressed: () => context.push('/inventory/create'),
                icon: const Icon(Icons.add),
                label: const Text('Lägg till'),
              ),
            ),
          ],
        );
      },
    );
  }
}

class _InventoryTile extends StatelessWidget {
  final InventoryItem item;

  const _InventoryTile({required this.item});

  @override
  Widget build(BuildContext context) {
    final subtitle = [
      '${item.quantity} ${item.unit}',
      if (item.location != null && item.location!.isNotEmpty) item.location!,
      if (item.bestBeforeDate != null) 'Bäst före: ${_formatDate(item.bestBeforeDate!)}',
    ].join(' · ');

    return ListTile(
      title: Text(item.productName),
      subtitle: Text(subtitle),
      trailing: item.opened
          ? const Chip(
              label: Text('Öppnad'),
              padding: EdgeInsets.zero,
              visualDensity: VisualDensity.compact,
            )
          : null,
      onTap: () => context.push('/inventory/${item.id}'),
    );
  }

  String _formatDate(String iso) {
    try {
      final dt = DateTime.parse(iso);
      return '${dt.year}-${dt.month.toString().padLeft(2, '0')}-${dt.day.toString().padLeft(2, '0')}';
    } catch (_) {
      return iso;
    }
  }
}