ttstd_family_care/lib/features/device/presentation/device_scan_page.dart

import 'package:cupertino_ui/cupertino_ui.dart';
import 'package:go_router/go_router.dart';
import 'package:image_picker/image_picker.dart';
import 'package:mobile_scanner/mobile_scanner.dart';

import '../../../core/widgets/feature_ui.dart';
import '../../../core/widgets/settings_ui.dart';
import '../../../l10n/app_localizations.dart';

/// 二维码扫描页。
///
/// 支持两种识别方式：
/// 1. 相机实时扫码（[MobileScanner] 的 `onDetect` 回调）；
/// 2. 从相册选取图片后离线解析（[MobileScannerController.analyzeImage]）。
///
/// 识别成功后通过 `context.pop(code)` 把结果回传给调用方（绑定设备页）。
class DeviceScanPage extends StatefulWidget {
  const DeviceScanPage({super.key});

  @override
  State<DeviceScanPage> createState() => _DeviceScanPageState();
}

class _DeviceScanPageState extends State<DeviceScanPage> {
  final MobileScannerController _controller = MobileScannerController(
    detectionSpeed: DetectionSpeed.noDuplicates,
    formats: const [BarcodeFormat.qrCode],
  );

  /// 防止连续回调导致多次 pop。
  bool _handled = false;

  /// 相册解析中，避免重复选图。
  bool _pickingImage = false;

  bool _torchOn = false;

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);

    return CupertinoPageScaffold(
      navigationBar: CupertinoNavigationBar(
        middle: Text(l10n.scanTitle),
        leading: CupertinoButton(
          padding: EdgeInsets.zero,
          child: const Icon(CupertinoIcons.back),
          onPressed: () => context.pop(),
        ),
        trailing: CupertinoButton(
          padding: EdgeInsets.zero,
          onPressed: _toggleTorch,
          child: Icon(
            _torchOn ? CupertinoIcons.lightbulb_fill : CupertinoIcons.lightbulb,
            size: 24,
          ),
        ),
      ),
      child: SafeArea(
        child: Column(
          children: [
            Expanded(
              child: Stack(
                fit: StackFit.expand,
                children: [
                  MobileScanner(
                    controller: _controller,
                    onDetect: (capture) => _onDetect(capture, l10n),
                    errorBuilder: (context, error, child) => _PermissionHint(
                      message: l10n.scanPermissionDenied,
                    ),
                  ),
                  // 取景框 + 提示文案
                  IgnorePointer(
                    child: Center(
                      child: Column(
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          Container(
                            width: 230,
                            height: 230,
                            decoration: BoxDecoration(
                              border: Border.all(
                                color: AppColors.green,
                                width: 3,
                              ),
                              borderRadius: BorderRadius.circular(20),
                            ),
                          ),
                          const SizedBox(height: 18),
                          Padding(
                            padding: const EdgeInsets.symmetric(horizontal: 40),
                            child: Text(
                              l10n.scanHint,
                              textAlign: TextAlign.center,
                              style: const TextStyle(
                                fontSize: 13.5,
                                color: CupertinoColors.white,
                                height: 1.5,
                              ),
                            ),
                          ),
                        ],
                      ),
                    ),
                  ),
                  if (_pickingImage)
                    const Positioned.fill(
                      child: ColoredBox(
                        color: Color(0x66000000),
                        child: Center(child: CupertinoActivityIndicator(radius: 14)),
                      ),
                    ),
                ],
              ),
            ),
            Padding(
              padding: const EdgeInsets.symmetric(vertical: 10),
              child: SecondaryButton(
                text: l10n.scanFromGallery,
                icon: CupertinoIcons.photo_on_rectangle,
                onPressed: _pickingImage ? null : () => _pickFromGallery(l10n),
              ),
            ),
          ],
        ),
      ),
    );
  }

  /// 相机识别回调：取首个非空条码值后回传并关闭页面。
  void _onDetect(BarcodeCapture capture, AppLocalizations l10n) {
    if (_handled) return;
    final code = _firstValue(capture);
    if (code == null) return;
    _handled = true;
    context.pop(code);
  }

  /// 从相册选取图片并离线解析二维码。
  Future<void> _pickFromGallery(AppLocalizations l10n) async {
    setState(() => _pickingImage = true);
    try {
      final picked = await ImagePicker().pickImage(source: ImageSource.gallery);
      if (picked == null) return;

      final capture = await _controller.analyzeImage(picked.path);
      final code = capture == null ? null : _firstValue(capture);
      if (!mounted) return;

      if (code == null) {
        await AppDialogs.alert(
          context,
          message: l10n.scanNoCodeFound,
          confirmText: l10n.commonConfirm,
        );
        return;
      }
      if (!mounted) return;
      _handled = true;
      context.pop(code);
    } finally {
      if (mounted) setState(() => _pickingImage = false);
    }
  }

  /// 切换闪光灯，失败时静默忽略（部分设备/模拟器不支持）。
  Future<void> _toggleTorch() async {
    try {
      await _controller.toggleTorch();
      if (mounted) setState(() => _torchOn = !_torchOn);
    } catch (_) {
      // 不支持闪光灯，忽略。
    }
  }

  /// 提取扫描结果中第一个有效的二维码文本。
  String? _firstValue(BarcodeCapture capture) {
    for (final barcode in capture.barcodes) {
      final value = barcode.rawValue;
      if (value != null && value.trim().isNotEmpty) return value.trim();
    }
    return null;
  }
}

/// 相机不可用（权限被拒或初始化失败）时的占位提示。
class _PermissionHint extends StatelessWidget {
  const _PermissionHint({required this.message});

  final String message;

  @override
  Widget build(BuildContext context) => ColoredBox(
        color: const Color(0xFF111827),
        child: Center(
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 40),
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                const Icon(
                  CupertinoIcons.video_camera,
                  size: 46,
                  color: CupertinoColors.white,
                ),
                const SizedBox(height: 14),
                Text(
                  message,
                  textAlign: TextAlign.center,
                  style: const TextStyle(
                    fontSize: 14,
                    color: CupertinoColors.white,
                    height: 1.5,
                  ),
                ),
              ],
            ),
          ),
        ),
      );
}