import 'package:flutter/material.dart';
import 'package:mobile_scanner/mobile_scanner.dart';
import 'package:provider/provider.dart';
import '../../providers/meal_planner_provider.dart';
import '../../qr_codec.dart';

class QrScanPage extends StatefulWidget {
  const QrScanPage({super.key});

  @override
  State<QrScanPage> createState() => _QrScanPageState();
}

class _QrScanPageState extends State<QrScanPage> {
  bool _handled = false;

  void _onDetect(BarcodeCapture capture, BuildContext context) {
    if (_handled) return;
    final raw = capture.barcodes.firstOrNull?.rawValue;
    if (raw == null) return;

    setState(() => _handled = true);

    final (plan, error) = parseMealPlanFromQr(raw);
    if (error != null) {
      _showError(context, error);
      return;
    }

    context.read<MealPlannerProvider>().importPlan(plan!);

    if (context.mounted) {
      Navigator.pop(context);
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Piano ricevuto!')),
      );
    }
  }

  void _showError(BuildContext context, String msg) {
    if (!context.mounted) return;
    Navigator.pop(context);
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(msg),
        backgroundColor: Theme.of(context).colorScheme.error,
      ),
    );
  }

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

    return Scaffold(
      appBar: AppBar(title: const Text('Scansiona QR')),
      body: Stack(
        children: [
          MobileScanner(
            onDetect: (capture) => _onDetect(capture, context),
          ),
          // cornice di mira
          Center(
            child: Container(
              width: 220,
              height: 220,
              decoration: BoxDecoration(
                border: Border.all(color: scheme.primary, width: 3),
                borderRadius: BorderRadius.circular(12),
              ),
            ),
          ),
          Positioned(
            bottom: 40,
            left: 0, right: 0,
            child: Text(
              'Inquadra il codice QR dell\'altro dispositivo',
              textAlign: TextAlign.center,
              style: const TextStyle(color: Colors.white, fontSize: 14),
            ),
          ),
        ],
      ),
    );
  }
}