umbrix/lib/features/common/qr_code_scanner_screen.dart

import 'package:dartx/dartx.dart';
import 'package:flutter/material.dart';
import 'package:flutter_hooks/flutter_hooks.dart';
import 'package:hiddify/core/localization/translations.dart';
import 'package:hiddify/utils/utils.dart';
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:mobile_scanner/mobile_scanner.dart';

class QRCodeScannerScreen extends HookConsumerWidget with PresLogger {
  const QRCodeScannerScreen({super.key});

  Future<String?> open(BuildContext context) async {
    return Navigator.of(context, rootNavigator: true).push(
      MaterialPageRoute(
        fullscreenDialog: true,
        builder: (context) => const QRCodeScannerScreen(),
      ),
    );
  }

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

    final controller = useMemoized(
      () => MobileScannerController(detectionTimeoutMs: 500),
    );

    useEffect(() => controller.dispose, []);

    final size = MediaQuery.sizeOf(context);
    final overlaySize = (size.shortestSide - 12).coerceAtMost(248);

    return Scaffold(
      extendBodyBehindAppBar: true,
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        iconTheme: Theme.of(context).iconTheme.copyWith(
              color: Colors.white,
              size: 32,
            ),
        actions: [
          IconButton(
            icon: ValueListenableBuilder(
              valueListenable: controller.torchState,
              builder: (context, state, child) {
                switch (state) {
                  case TorchState.off:
                    return const Icon(Icons.flash_off, color: Colors.grey);
                  case TorchState.on:
                    return const Icon(Icons.flash_on, color: Colors.yellow);
                }
              },
            ),
            tooltip: t.profile.add.qrScanner.torchSemanticLabel,
            onPressed: () => controller.toggleTorch(),
          ),
          IconButton(
            icon: ValueListenableBuilder(
              valueListenable: controller.cameraFacingState,
              builder: (context, state, child) {
                switch (state) {
                  case CameraFacing.front:
                    return const Icon(Icons.camera_front);
                  case CameraFacing.back:
                    return const Icon(Icons.camera_rear);
                }
              },
            ),
            tooltip: t.profile.add.qrScanner.facingSemanticLabel,
            onPressed: () => controller.switchCamera(),
          ),
        ],
      ),
      body: Stack(
        children: [
          MobileScanner(
            controller: controller,
            onDetect: (capture) {
              final rawData = capture.barcodes.first.rawValue;
              loggy.debug('captured raw: [$rawData]');
              if (rawData != null) {
                final uri = Uri.tryParse(rawData);
                if (context.mounted && uri != null) {
                  loggy.debug('captured url: [$uri]');
                  Navigator.of(context, rootNavigator: true)
                      .pop(uri.toString());
                }
              } else {
                loggy.warning("unable to capture");
              }
            },
            errorBuilder: (_, error, __) {
              final message = switch (error.errorCode) {
                MobileScannerErrorCode.permissionDenied =>
                  t.profile.add.qrScanner.permissionDeniedError,
                _ => t.profile.add.qrScanner.unexpectedError,
              };

              return Center(
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    const Padding(
                      padding: EdgeInsets.only(bottom: 8),
                      child: Icon(Icons.error, color: Colors.white),
                    ),
                    Text(message),
                    Text(error.errorDetails?.message ?? ''),
                  ],
                ),
              );
            },
          ),
          CustomPaint(
            painter: ScannerOverlay(
              Rect.fromCenter(
                center: size.center(Offset.zero),
                width: overlaySize,
                height: overlaySize,
              ),
            ),
          ),
        ],
      ),
    );
  }
}

class ScannerOverlay extends CustomPainter {
  ScannerOverlay(this.scanWindow);

  final Rect scanWindow;
  final double borderRadius = 12.0;

  @override
  void paint(Canvas canvas, Size size) {
    final backgroundPath = Path()..addRect(Rect.largest);
    final cutoutPath = Path()
      ..addRRect(
        RRect.fromRectAndCorners(
          scanWindow,
          topLeft: Radius.circular(borderRadius),
          topRight: Radius.circular(borderRadius),
          bottomLeft: Radius.circular(borderRadius),
          bottomRight: Radius.circular(borderRadius),
        ),
      );

    final backgroundPaint = Paint()
      ..color = Colors.black.withOpacity(0.5)
      ..style = PaintingStyle.fill
      ..blendMode = BlendMode.dstOut;

    final backgroundWithCutout = Path.combine(
      PathOperation.difference,
      backgroundPath,
      cutoutPath,
    );

    final borderPaint = Paint()
      ..color = Colors.white
      ..style = PaintingStyle.stroke
      ..strokeWidth = 3.0;

    final borderRect = RRect.fromRectAndCorners(
      scanWindow,
      topLeft: Radius.circular(borderRadius),
      topRight: Radius.circular(borderRadius),
      bottomLeft: Radius.circular(borderRadius),
      bottomRight: Radius.circular(borderRadius),
    );

    canvas.drawPath(backgroundWithCutout, backgroundPaint);
    canvas.drawRRect(borderRect, borderPaint);
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return false;
  }
}