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

import '../../core/auth/auth_provider.dart';
import '../../l10n/app_localizations.dart';
import '../../shared/models/product.dart';
import 'food_product_service.dart';
import 'product_portion_sheet.dart';

/// Screen that activates the device camera to scan a barcode.
/// On successful scan it looks up the catalog product and shows
/// [ProductPortionSheet] to confirm the portion before adding to diary.
class BarcodeScanScreen extends ConsumerStatefulWidget {
  const BarcodeScanScreen({
    super.key,
    required this.mealType,
    required this.date,
    required this.onAdded,
  });

  final String mealType;
  final String date;
  final VoidCallback onAdded;

  @override
  ConsumerState<BarcodeScanScreen> createState() => _BarcodeScanScreenState();
}

class _BarcodeScanScreenState extends ConsumerState<BarcodeScanScreen> {
  bool _scanning = true;

  void _onBarcodeDetected(BarcodeCapture capture) async {
    if (!_scanning) return;
    final rawValue = capture.barcodes.firstOrNull?.rawValue;
    if (rawValue == null) return;

    setState(() => _scanning = false);

    final l10n = AppLocalizations.of(context)!;
    final service = FoodProductService(ref.read(apiClientProvider));
    final catalogProduct = await service.getByBarcode(rawValue);

    if (!mounted) return;

    if (catalogProduct == null) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(l10n.productNotFound)),
      );
      setState(() => _scanning = true);
      return;
    }

    _showPortionSheet(catalogProduct);
  }

  void _showPortionSheet(CatalogProduct catalogProduct) {
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      builder: (_) => ProductPortionSheet(
        catalogProduct: catalogProduct,
        onConfirm: (portionGrams) => _addToDiary(catalogProduct, portionGrams),
      ),
    ).then((_) {
      if (mounted) setState(() => _scanning = true);
    });
  }

  Future<void> _addToDiary(
      CatalogProduct catalogProduct, double portionGrams) async {
    final l10n = AppLocalizations.of(context)!;
    try {
      await ref.read(apiClientProvider).post('/diary', data: {
        'product_id': catalogProduct.id,
        'portion_g': portionGrams,
        'meal_type': widget.mealType,
        'date': widget.date,
        'source': 'barcode',
      });
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(catalogProduct.displayName)),
        );
        widget.onAdded();
        Navigator.pop(context);
      }
    } catch (_) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(l10n.addFailed)),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    return Scaffold(
      appBar: AppBar(title: Text(l10n.scanBarcode)),
      body: MobileScanner(
        onDetect: _onBarcodeDetected,
      ),
    );
  }
}