import 'dart:async';
import 'dart:convert' show jsonEncode;
import 'dart:ui' as ui show PlatformDispatcher;

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:wakelock_plus/wakelock_plus.dart';

import '../auth/session_store.dart';
import '../detection/detection_result.dart';
import '../detection/detector_worker.dart';
import '../feedback/feedback_api.dart';
import '../feedback/false_target_capture.dart';
import '../models/model_manager.dart';
import '../reminder/reminder.dart';
import 'app_camera_controller.dart';
import 'camera_view_model.dart';
import 'detection_overlay.dart';
import 'frame_analyzer.dart';
import 'model_catalog_section.dart';

/// 主界面：相机预览 + 检测框 overlay + 顶栏(返回/切换摄像头)
class CameraScreen extends StatefulWidget {
  const CameraScreen({super.key});

  @override
  State<CameraScreen> createState() => _CameraScreenState();
}

class _CameraScreenState extends State<CameraScreen> {
  CameraViewModel? _viewModel;
  FrameAnalyzer? _analyzer;
  AppCameraController? _cameraController;
  bool _initFailed = false;
  bool _permissionGranted = false;
  String? _globalError;
  String? _initError;

  /// 置信度阈值（设置页滑块调整，worker 内实时生效）
  double _minScore = 0.10;

  /// 原生侧帧状态轮询结果（诊断用；无帧时诊断行也能实时刷新）
  Map<dynamic, dynamic> _nativeStats = const {};
  Timer? _statsTimer;

  /// 当前 worker 已加载的模型 id 集合（激活集变化对比用）
  Set<int> _loadedModelIds = const {};

  /// 进行中的 worker 重建（并发调用共享，避免重复建/漏建）
  Future<void>? _reloadInFlight;

  /// ModelManager revision 快照：模型文件更新（自动更新下载新版）也需重建 worker
  int _lastRevision = -1;

  /// C 端状态胶囊：3 秒内连点 5 次切换完整开发诊断（远程收截图报障仍可取数）
  bool _devInfo = false;
  final List<DateTime> _devTaps = [];

  /// 推理 worker 后台重建中（启用/停用模型触发）：期间 modelReady 仍为 false，
  /// 胶囊与顶部横幅显示「识别准备中」，不误报「模型加载失败」
  bool _workerPending = false;

  /// 假目标上报进行中（防重复触发）
  bool _reporting = false;

  static const _falseTargetConsent = FlutterSecureStorage();

  void _onDevTaps() {
    final now = DateTime.now();
    _devTaps.add(now);
    _devTaps
        .removeWhere((t) => now.difference(t) > const Duration(seconds: 3));
    if (_devTaps.length < 5) return;
    _devTaps.clear();
    setState(() => _devInfo = !_devInfo);
  }

  /// 识别延迟分档（C 端直观读法：流畅 / 一般 / 偏慢）
  ({String label, Color color}) _latencyBucket(double avgMs) {
    if (avgMs <= 200) return (label: '流畅', color: Colors.greenAccent);
    if (avgMs <= 600) return (label: '一般', color: Colors.amberAccent);
    return (label: '偏慢', color: Colors.redAccent);
  }

  /// C 端底部状态胶囊内容：设备识别延迟（近帧滚动平均）+ 当前识别模型
  List<Widget> _statusCapsuleLines(CameraUiState s) {
    if (!s.modelReady) {
      if (_workerPending) {
        // worker 后台构建中（用户刚启用模型）：给个进行时状态，别误读为未启用
        return const [
          Text(
            '识别准备中…',
            style: TextStyle(color: Colors.white70, fontSize: 13),
          ),
        ];
      }
      return const [
        Text(
          '仅预览 · 未启用识别',
          style: TextStyle(color: Colors.orangeAccent, fontSize: 12),
        ),
      ];
    }
    final avg = s.latencyAvgMs;
    final lines = <Widget>[];
    if (avg == null) {
      lines.add(const Text(
        '识别延迟 --',
        style: TextStyle(color: Colors.white54, fontSize: 13),
      ));
    } else {
      final b = _latencyBucket(avg);
      lines.add(Text(
        '识别延迟 ${(avg / 1000).toStringAsFixed(2)} 秒 · ${b.label}',
        style: TextStyle(
          color: b.color,
          fontSize: 13,
          fontWeight: FontWeight.w600,
        ),
      ));
    }
    final names = ModelManager.instance.modelsLabel;
    if (names.isNotEmpty && names != '未下载') {
      lines.add(Text(
        '识别模型：$names',
        textAlign: TextAlign.center,
        style: const TextStyle(color: Colors.white54, fontSize: 10.5),
      ));
    }
    return lines;
  }

  void _openSettings() {
    final vm = _viewModel;
    if (vm == null) return;
    ModelManager.instance.refresh();
    showModalBottomSheet<void>(
      context: context,
      isScrollControlled: true,
      backgroundColor: Colors.black87,
      builder: (ctx) => StatefulBuilder(
        // 弹层高度 ≤ 70% 屏高：超过会盖满全屏使遮罩无处点按，弹层无法关闭
        builder: (ctx, setSheetState) => ConstrainedBox(
          constraints: BoxConstraints(
            maxHeight: MediaQuery.of(ctx).size.height * 0.7,
          ),
          child: SingleChildScrollView(
            child: Padding(
              padding: const EdgeInsets.all(20),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  const Text(
                    '识别设置',
                    style: TextStyle(
                      color: Colors.white,
                      fontSize: 16,
                      fontWeight: FontWeight.bold,
                    ),
                  ),
                  const SizedBox(height: 12),
                  Row(
                    children: [
                      const Text(
                        '置信度阈值',
                        style: TextStyle(color: Colors.white70, fontSize: 14),
                      ),
                      const Spacer(),
                      Text(
                        '${(_minScore * 100).toStringAsFixed(0)}%',
                        style: const TextStyle(
                          color: Colors.greenAccent,
                          fontSize: 14,
                          fontWeight: FontWeight.bold,
                        ),
                      ),
                    ],
                  ),
                  Slider(
                    value: _minScore,
                    min: 0.05,
                    max: 0.50,
                    divisions: 45,
                    activeColor: Colors.greenAccent,
                    onChanged: (v) {
                      setSheetState(() => _minScore = v);
                      _analyzer?.worker?.setMinScore(v);
                    },
                  ),
                  const SizedBox(height: 8),
                  const Text(
                    '阈值越低识别越灵敏（低分框越多，误报也可能增加）',
                    style: TextStyle(color: Colors.white54, fontSize: 12),
                  ),
                  const SizedBox(height: 16),
                  const Divider(color: Colors.white12),
                  const SizedBox(height: 8),
                  ModelCatalogSection(manager: ModelManager.instance),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }

  /// 假目标上报：一键上报当前画面——按一次快照帧（与喂给 YOLO 的帧同源同尺寸）
  /// + 当前全部检测框快照，单独同意（首次）→ isolate 内整帧 jpg 重编码
  /// （剥离全部元数据）→ 上传。无任何额外选择步骤，取消/失败不影响识别。
  Future<void> _startFalseTargetReport() async {
    final analyzer = _analyzer;
    final vm = _viewModel;
    if (_reporting || analyzer == null || vm == null || !vm.state.modelReady) {
      return;
    }
    _reporting = true;
    try {
      final snap = await analyzer
          .takeSnapshot()
          .timeout(const Duration(seconds: 2), onTimeout: () => null);
      if (!mounted || snap == null) {
        _toast('未获取到画面，请稍后重试');
        return;
      }
      final ok = await _ensureFalseTargetConsent();
      if (!mounted || !ok) return;
      _toast('正在上报…');
      final boxes = List<DetectionResult>.of(vm.state.results)
          .where((b) => b.width > 0 && b.height > 0)
          .toList();
      final detections = jsonEncode([
        for (final b in boxes)
          {
            'label': b.label,
            'class': b.classId,
            'score': double.parse(b.score.toStringAsFixed(4)),
            'model': b.modelName,
            'cx': double.parse(b.centerX.toStringAsFixed(6)),
            'cy': double.parse(b.centerY.toStringAsFixed(6)),
            'w': double.parse(b.width.toStringAsFixed(6)),
            'h': double.parse(b.height.toStringAsFixed(6)),
          },
      ]);
      final jpeg = await compute(encodeFrameJpeg, snap);
      await FeedbackApi(sessionStore: SessionStore()).reportFalseTarget(
        jpeg: jpeg,
        detectionsJson: detections,
        sourceW: snap.width,
        sourceH: snap.height,
      );
      _toast('感谢反馈！我们会用它改进识别');
    } catch (e) {
      _toast('上报失败: $e');
    } finally {
      _reporting = false;
    }
  }

  /// 单独同意（PIPL）：首次上报前弹说明，可拒绝且不影响识别；同意后记录不再弹
  Future<bool> _ensureFalseTargetConsent() async {
    if (await _falseTargetConsent.read(key: falseTargetConsentKey) == '1') {
      return true;
    }
    if (!mounted) return false;
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('上报说明'),
        content: const Text(
          '将上传当前画面一帧（与识别使用的画面一致，上传前已在本地重新编码、'
          '移除位置等全部照片信息）及当时的识别框，用于改进识别模型。\n\n'
          '该功能完全自愿，拒绝不影响任何其他功能。已上传的图片可联系客服删除。',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(ctx).pop(false),
            child: const Text('暂不上报'),
          ),
          FilledButton(
            onPressed: () => Navigator.of(ctx).pop(true),
            child: const Text('同意并继续'),
          ),
        ],
      ),
    );
    if (ok == true) {
      await _falseTargetConsent.write(key: falseTargetConsentKey, value: '1');
    }
    return ok == true;
  }

  void _toast(String msg) {
    if (!mounted) return;
    ScaffoldMessenger.of(context)
      ..hideCurrentSnackBar()
      ..showSnackBar(SnackBar(
          content: Text(msg), duration: const Duration(seconds: 2)));
  }

  @override
  void initState() {
    super.initState();
    final oldPlatform = ui.PlatformDispatcher.instance.onError;
    ui.PlatformDispatcher.instance.onError = (error, stack) {
      setState(
        () => _globalError =
            'Platform: $error\n${stack.toString().split('\n').take(3).join('\n')}',
      );
      return oldPlatform?.call(error, stack) ?? false;
    };
    WidgetsBinding.instance.addPostFrameCallback((_) => _init());
    // 相机页常亮：野外观察时保持屏幕不熄（离开页面时关闭）
    WakelockPlus.enable();
    // 每秒轮询原生侧帧状态：无帧时诊断行也能实时刷新（camErr/计数）
    _statsTimer = Timer.periodic(
      const Duration(seconds: 1),
      (_) => _pollStats(),
    );
    // 模型清单激活集变化（下载完成自动激活/取消激活）时重建推理 worker
    ModelManager.instance.addListener(_onModelsChanged);
  }

  Future<void> _pollStats() async {
    final camera = _cameraController;
    if (camera == null) return;
    final s = await camera.stats();
    if (!mounted) return;
    setState(() => _nativeStats = s);
  }

  Future<void> _init() async {
    final granted = await Permission.camera.request().isGranted;
    if (!mounted) return;
    setState(() => _permissionGranted = granted);
    if (!granted) return;

    // 新识别会话（2026-09-03）：不恢复上次启用的模型——每次进入都从仅预览开始，
    // 识别需用户在模型清单手动启用；崩溃/坏模型不会自动复现。激活集变化经
    // _onModelsChanged 重建 worker 挂载
    ModelManager.instance.resetForSession();
    // 目录同步先行（缓存优先，2026-09-03）：进页面立即触发——refresh 开头先把
    // 上次成功目录从磁盘载入并 notify，设置弹层打开即有内容（不完全依赖网络）；
    // 网络拉取/自动更新在后台继续，全程不阻塞预览
    unawaited(ModelManager.instance.refresh());
    // 先出预览：占位 analyzer（无 worker）让相机立即启动，识别加载完再原地挂上
    if (_analyzer == null) {
      final vm = CameraViewModel(reminder: Reminder());
      _viewModel = vm;
      _analyzer = FrameAnalyzer(worker: null, viewModel: vm);
    }
    await _startCamera();
  }

  /// 用当前激活模型重建推理 worker（启用/停用模型、模型文件更新时调用）；
  /// worker 为 null（无启用模型或加载失败）时仅预览并提示。
  /// 并发调用共享同一进行中的重建：进行中时先等完成再复查，期间变化不丢失。
  Future<void> _reloadWorker() {
    final inFlight = _reloadInFlight;
    if (inFlight != null) {
      // 重建进行中：完成后按最新状态复查，期间的变化不丢失
      return inFlight.then((_) => _reloadWorker()).catchError((_) {});
    }
    if (mounted) setState(() => _workerPending = true);
    _reloadInFlight = _doReloadWorker().whenComplete(() {
      _reloadInFlight = null;
      if (mounted) setState(() => _workerPending = false);
    });
    return _reloadInFlight!;
  }

  Future<void> _doReloadWorker() async {
    final mgr = ModelManager.instance;
    final models = mgr.models;
    final ids = models.map((m) => m.datasetId).toSet();
    final revChanged = mgr.revision != _lastRevision;
    if (_viewModel != null &&
        !revChanged &&
        _loadedModelIds.length == ids.length &&
        _loadedModelIds.containsAll(ids)) {
      return; // 激活集/模型文件未变（进度/目录刷新通知）直接跳过
    }
    _lastRevision = mgr.revision;
    final worker = await DetectorWorker.create(models: models);
    _loadedModelIds = ids;
    if (!mounted) {
      worker?.dispose();
      return; // 页面已关闭：不触碰可能已 dispose 的 vm/analyzer
    }
    final vm = _viewModel ?? CameraViewModel(reminder: Reminder());
    vm.setModelReady(worker != null);
    // 重建后把设置页调过的阈值落到新 worker（避免静默回到默认值）
    worker?.setMinScore(_minScore);
    final existing = _analyzer;
    if (existing == null) {
      // 相机尚未绑定 analyzer（冷启动竞态兜底）：直接以新 worker 建 analyzer
      final analyzer = FrameAnalyzer(worker: worker, viewModel: vm);
      setState(() {
        _viewModel = vm;
        _analyzer = analyzer;
      });
      if (_cameraController != null) {
        await _cameraController!.start(analyzer);
      }
      return;
    }
    // 相机已绑定（预览中）：worker 原地挂到既有 analyzer——帧流回调闭包捕获的
    // 是 analyzer 对象本身，替换其 worker 双平台即时生效；重启相机会重新
    // initialize（iOS ~1s+）且预览闪断，一律避免（2026-09-03）
    existing.attachWorker(worker);
  }

  void _onModelsChanged() {
    final mgr = ModelManager.instance;
    final ids = mgr.models.map((m) => m.datasetId).toSet();
    final revChanged = mgr.revision != _lastRevision;
    if (!revChanged &&
        _loadedModelIds.length == ids.length &&
        _loadedModelIds.containsAll(ids)) {
      return;
    }
    _reloadWorker();
  }

  Future<void> _startCamera() async {
    final analyzer = _analyzer;
    if (analyzer == null) return;
    try {
      final controller = await AppCameraController.create();
      if (controller == null) {
        setState(() {
          _initFailed = true;
          _initError = '未找到可用摄像头';
        });
        return;
      }
      await controller.start(analyzer);
      if (!mounted) {
        controller.stop();
        return;
      }
      setState(() {
        _cameraController = controller;
        _initFailed = false;
        _initError = null;
      });
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _initFailed = true;
        _initError = '$e';
      });
    }
  }

  @override
  void dispose() {
    ModelManager.instance.removeListener(_onModelsChanged);
    _statsTimer?.cancel();
    WakelockPlus.disable();
    _cameraController?.stop();
    _analyzer?.dispose();
    _viewModel?.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final vm = _viewModel;
    final camera = _cameraController;

    return Scaffold(
      backgroundColor: Colors.black,
      body: Stack(
        fit: StackFit.expand,
        children: [
          if (!_permissionGranted)
            _PermissionGuide(onRequest: () => _init())
          else if (vm != null && (camera?.isInitialized ?? false))
            // 预览 + 检测框同几何：overlay 作为预览 widget 的 sibling，
            // 与纹理共享同一 Stack/尺寸，避免比例或裁剪导致的位置偏移。
            // 两平台分析帧都已竖屏（Android 原生侧旋转 / iOS 插件本来就竖屏），
            // rotation 恒 0，CoordinateMapper 走纯 FIT_COVER 缩放路径
            ListenableBuilder(
              listenable: vm,
              builder: (context, _) => _ZoomablePreview(
                controller: camera!,
                overlay: DetectionOverlay(
                  results: vm.state.results,
                  rotation: 0,
                  imageWidthPx: vm.state.imageWidthPx,
                  imageHeightPx: vm.state.imageHeightPx,
                ),
              ),
            )
          else if (camera?.isInitialized ?? false)
            _ZoomablePreview(controller: camera!)
          else
            const Center(
              child: Text('相机启动中…', style: TextStyle(color: Colors.white70)),
            ),

          // 帧级动态层（横幅/诊断行）单独订阅 viewModel，避免整屏重建
          if (vm != null)
            ListenableBuilder(
              listenable: vm,
              builder: (context, _) => _buildDiagnosticsLayer(camera),
            ),

          if (_initFailed)
            Center(
              child: Container(
                padding: const EdgeInsets.all(24),
                decoration: BoxDecoration(
                  color: Colors.black54,
                  borderRadius: BorderRadius.circular(12),
                ),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    const Text(
                      '相机初始化失败',
                      style: TextStyle(color: Colors.white),
                    ),
                    if (_initError != null)
                      Padding(
                        padding: const EdgeInsets.only(top: 8),
                        child: Text(
                          _initError!,
                          maxLines: 3,
                          overflow: TextOverflow.ellipsis,
                          textAlign: TextAlign.center,
                          style: const TextStyle(
                            color: Colors.redAccent,
                            fontSize: 11,
                          ),
                        ),
                      ),
                    TextButton(
                      onPressed: () {
                        setState(() => _initFailed = false);
                        _startCamera();
                      },
                      child: const Text('重试'),
                    ),
                  ],
                ),
              ),
            ),

          Positioned(
            top: MediaQuery.of(context).padding.top + 8,
            left: 0,
            right: 0,
            child: _CameraTopBar(
              onClose: () => Navigator.of(context).pop(),
              onOpenSettings: _openSettings,
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildDiagnosticsLayer(AppCameraController? camera) {
    final vm = _viewModel!;
    return Stack(
      fit: StackFit.expand,
      children: [
        // 模型热更新下载失败提示（已加载模型仍可用，仅提示补更新）
        if (vm.state.modelReady && ModelManager.instance.error != null)
          Positioned(
            left: 16,
            right: 16,
            top: MediaQuery.of(context).padding.top + 56,
            child: Container(
              padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
              decoration: BoxDecoration(
                color: Colors.black54,
                borderRadius: BorderRadius.circular(8),
              ),
              child: Text(
                ModelManager.instance.error!,
                textAlign: TextAlign.center,
                style: const TextStyle(color: Colors.orange, fontSize: 12),
              ),
            ),
          ),

        // 模型未加载时仅显示相机预览，不做检测标注（横幅置于顶栏下方，避免与底部诊断行重叠）；
        // worker 后台构建中不提示「加载失败」（modelReady 就绪前的一瞬）
        if (!vm.state.modelReady && !_workerPending)
          Positioned(
            left: 16,
            right: 16,
            top: MediaQuery.of(context).padding.top + 56,
            child: Container(
              padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
              decoration: BoxDecoration(
                color: Colors.black54,
                borderRadius: BorderRadius.circular(8),
              ),
              child: Text(
                ModelManager.instance.models.isEmpty
                    ? '未使用模型：点右上角设置，在「模型清单」中选择要使用的模型'
                    : '识别模型加载失败:${DetectorWorker.lastLoadError ?? '未知原因'}\n最后步骤:${DetectorWorker.lastLog ?? '-'}',
                textAlign: TextAlign.center,
                style: const TextStyle(color: Colors.orange, fontSize: 14),
              ),
            ),
          ),

        // 假目标上报入口：识别就绪且有框时出现（完全自愿，可忽略）
        if (vm.state.modelReady && vm.state.results.isNotEmpty && !_workerPending)
          Positioned(
            left: 12,
            bottom: MediaQuery.of(context).padding.bottom + 72,
            child: Material(
              color: Colors.black54,
              borderRadius: BorderRadius.circular(18),
              child: InkWell(
                borderRadius: BorderRadius.circular(18),
                onTap: _startFalseTargetReport,
                child: const Padding(
                  padding: EdgeInsets.symmetric(horizontal: 12, vertical: 7),
                  child: Row(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Icon(Icons.flag_outlined,
                          color: Colors.orangeAccent, size: 16),
                      SizedBox(width: 5),
                      Text('误报上报',
                          style: TextStyle(color: Colors.white70, fontSize: 13)),
                    ],
                  ),
                ),
              ),
            ),
          ),

        Positioned(
          left: 8,
          right: 8,
          bottom: MediaQuery.of(context).padding.bottom + 8,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: [
              // C 端状态胶囊：识别延迟 + 识别模型（连点 5 次展开完整开发诊断）
              GestureDetector(
                behavior: HitTestBehavior.opaque,
                onTap: _onDevTaps,
                child: Container(
                  padding: const EdgeInsets.symmetric(
                      horizontal: 14, vertical: 6),
                  decoration: BoxDecoration(
                    color: Colors.black54,
                    borderRadius: BorderRadius.circular(16),
                  ),
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    crossAxisAlignment: CrossAxisAlignment.center,
                    children: _statusCapsuleLines(vm.state),
                  ),
                ),
              ),
              // —— 开发诊断（默认隐藏，远程排查用）——
              if (_devInfo) ...[
                const SizedBox(height: 4),
                const Text(
                  '开发诊断（连点上方状态胶囊 5 次收起）',
                  style: TextStyle(color: Colors.white24, fontSize: 10),
                ),
                Text(
                  '阈值:${(_minScore * 100).toStringAsFixed(0)}% 模型:${vm.state.modelReady ? ModelManager.instance.modelsLabel : '未加载'} 帧:${vm.state.framesReceived} 流:${camera?.streamCallbacks ?? 0} 推理:${vm.state.debugDetectCalls}次 异常:${vm.state.debugDetectErrors}次 处理:${vm.state.debugLastMs}ms 平均:${vm.state.latencyAvgMs?.toStringAsFixed(0) ?? '-'}ms 最高分:${(vm.state.debugHighestScore * 100).toStringAsFixed(1)}% 图:${vm.state.imageWidthPx}x${vm.state.imageHeightPx} 传感:${camera?.sensorOrientation ?? '-'} 屏转:${camera?.displayDegrees ?? '-'} 旋:${camera?.rotationDegrees ?? 0} turn:${camera?.quarterTurns ?? '-'}',
                  style: const TextStyle(color: Colors.white70, fontSize: 12),
                ),
                if (_nativeStats.isNotEmpty)
                  Text(
                    '原生:回调${_nativeStats['callbacks'] ?? '-'} 发出${_nativeStats['emitOk'] ?? '-'} 异常${_nativeStats['emitErr'] ?? '-'} 无订阅${_nativeStats['sinkNull'] ?? '-'} sink:${_nativeStats['sink'] ?? '-'} 配置:${_nativeStats['size'] ?? '-'} 发帧:${_nativeStats['emitSize'] ?? '-'} 错误:${_nativeStats['error'] ?? '无'} 轮询:${_nativeStats['pollErr'] ?? 'ok'}${vm.state.results.isEmpty ? '' : ' 框1:(${vm.state.results.first.left.toStringAsFixed(2)},${vm.state.results.first.top.toStringAsFixed(2)},${vm.state.results.first.right.toStringAsFixed(2)},${vm.state.results.first.bottom.toStringAsFixed(2)})'}',
                    style: const TextStyle(
                      color: Colors.amberAccent,
                      fontSize: 11,
                    ),
                  ),
                if (vm.state.debugYuv.isNotEmpty)
                  Text(
                    'yuv:${vm.state.debugYuv}',
                    style: const TextStyle(
                      color: Colors.yellowAccent,
                      fontSize: 11,
                    ),
                  ),
                if (camera != null)
                  Text(
                    'streaming:${camera.isStreaming} '
                    'camErr:${camera.errorDescription ?? '无'}',
                    maxLines: 2,
                    overflow: TextOverflow.ellipsis,
                    style: const TextStyle(
                      color: Colors.cyanAccent,
                      fontSize: 11,
                    ),
                  ),
                if (vm.state.debugLastError != null)
                  Text(
                    vm.state.debugLastError!,
                    maxLines: 2,
                    overflow: TextOverflow.ellipsis,
                    textAlign: TextAlign.center,
                    style:
                        const TextStyle(color: Colors.redAccent, fontSize: 11),
                  ),
                if (_globalError != null)
                  Text(
                    _globalError!,
                    maxLines: 3,
                    overflow: TextOverflow.ellipsis,
                    textAlign: TextAlign.center,
                    style:
                        const TextStyle(color: Colors.redAccent, fontSize: 11),
                  ),
              ],
            ],
          ),
        ),
      ],
    );
  }
}

/// 双指捏合缩放预览；overlay 与纹理同几何（Stack 内同尺寸）
class _ZoomablePreview extends StatefulWidget {
  final AppCameraController controller;

  /// 检测框 overlay（随帧更新，与纹理同区域）
  final Widget? overlay;

  const _ZoomablePreview({required this.controller, this.overlay});

  @override
  State<_ZoomablePreview> createState() => _ZoomablePreviewState();
}

class _ZoomablePreviewState extends State<_ZoomablePreview> {
  double _minZoom = 1.0;
  double _maxZoom = 1.0;
  double _currentZoom = 1.0;
  double _gestureStartZoom = 1.0;

  @override
  void initState() {
    super.initState();
    widget.controller.getMinZoomLevel().then((v) {
      if (mounted) setState(() => _minZoom = v);
    });
    widget.controller.getMaxZoomLevel().then((v) {
      if (mounted) setState(() => _maxZoom = v);
    });
  }

  @override
  Widget build(BuildContext context) {
    // 预览铺满全屏（cover 裁剪由插件按视图比例完成）；
    // overlay 与纹理同几何：作为 Stack sibling 叠在上层，坐标与纹理区域一致
    return GestureDetector(
      onScaleStart: (_) => _gestureStartZoom = _currentZoom,
      onScaleUpdate: (d) {
        final target = (_gestureStartZoom * d.scale).clamp(_minZoom, _maxZoom);
        if ((target - _currentZoom).abs() < 0.01) return;
        _currentZoom = target;
        widget.controller.setZoomLevel(target);
      },
      child: Stack(
        fit: StackFit.expand,
        children: [
          widget.controller.buildPreview(),
          if (widget.overlay != null) widget.overlay!,
        ],
      ),
    );
  }
}

class _CameraTopBar extends StatelessWidget {
  final VoidCallback onClose;
  final VoidCallback onOpenSettings;

  const _CameraTopBar({required this.onClose, required this.onOpenSettings});

  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.black54,
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 4),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          IconButton(
            tooltip: '返回',
            icon: const Icon(Icons.arrow_back, color: Colors.white),
            onPressed: onClose,
          ),
          IconButton(
            tooltip: '识别设置',
            icon: const Icon(Icons.tune, color: Colors.white70),
            onPressed: onOpenSettings,
          ),
        ],
      ),
    );
  }
}

class _PermissionGuide extends StatelessWidget {
  final VoidCallback onRequest;

  const _PermissionGuide({required this.onRequest});

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Text('需要相机权限才能进行实时识别', style: TextStyle(color: Colors.white)),
          const SizedBox(height: 16),
          FilledButton(onPressed: onRequest, child: const Text('授权相机')),
        ],
      ),
    );
  }
}