flutter_integrated_whb/lib/pages/home/study/face_ecognition_page.dart

import 'dart:async';
import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:qhd_prevention/customWidget/custom_button.dart';
import 'package:qhd_prevention/pages/my_appbar.dart';
import 'package:qhd_prevention/tools/tools.dart';
import '../../../http/ApiService.dart';

/// 人脸识别模式
enum FaceMode { auto, manual }

class FaceRecognitionPage extends StatefulWidget {
  final String studentId;
  final FaceMode mode;

  const FaceRecognitionPage({
    Key? key,
    this.studentId = '',
    required this.mode,
  }) : super(key: key);

  @override
  _FaceRecognitionPageState createState() => _FaceRecognitionPageState();
}

class _FaceRecognitionPageState extends State<FaceRecognitionPage> {
  CameraController? _cameraController;
  Timer? _timer;
  int _attempts = 0;
  String _message = '';
  String _tip = '请将人脸置于圆圈内';

  static const int _maxAttempts = 8;
  static const Duration _interval = Duration(seconds: 2);

  bool get _isManualMode => widget.mode == FaceMode.manual;

  @override
  void initState() {
    super.initState();
    _initCamera();
  }

  @override
  void dispose() {
    _timer?.cancel();
    _cameraController?.dispose();
    super.dispose();
  }

  Future<void> _initCamera() async {
    final cams = await availableCameras();
    final front = cams.firstWhere((c) => c.lensDirection == CameraLensDirection.front);
    _cameraController = CameraController(front, ResolutionPreset.medium, enableAudio: false);
    await _cameraController!.initialize();
    if (!mounted) return;
    setState(() {});

    if (!_isManualMode) {
      _timer = Timer.periodic(_interval, (_) => _captureAndUpload());
    }
  }

  Future<void> _captureAndUpload() async {
    if (_isManualMode) {
      setState(() => _message = '请将人脸置于圆圈内');
    } else {
      if (_attempts >= _maxAttempts) return _onTimeout();
      _attempts++;
    }

    try {
      final pic = await _cameraController!.takePicture();
      final res = await ApiService.getUserFace(pic.path, widget.studentId);
      if (res['result'] == 'success') {
        _onSuccess();
      } else {
        setState(() => _message = '识别失败，请重试');
      }
    } catch (_) {
      setState(() => _message = '发生错误，请重试');
    }
  }

  Future<void> _captureAndReload() async {
    setState(() => _message = '上传中...');
    try {
      final pic = await _cameraController!.takePicture();
      final res = await ApiService.reloadMyFace(pic.path);
      if (res['result'] == 'success') {
        _onSuccess();
      } else {
        setState(() => _message = '验证失败，请重试');
      }
    } catch (_) {
      setState(() => _message = '发生错误，请重试');
    }
  }

  void _onSuccess() {
    _timer?.cancel();
    ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('验证成功')));
    Future.delayed(const Duration(milliseconds: 800), () => Navigator.of(context).pop(true));
  }

  void _onTimeout() {
    _timer?.cancel();
    setState(() => _message = '人脸超时，请重新识别！');
    Future.delayed(const Duration(seconds: 3), () => Navigator.of(context).pop(false));
  }

  @override
  Widget build(BuildContext context) {
    if (_cameraController == null || !_cameraController!.value.isInitialized) {
      return const Scaffold(
        backgroundColor: Colors.white,
        body: Center(child: CircularProgressIndicator()),
      );
    }
    final previewSize = _cameraController!.value.previewSize!;
    final previewAspect = previewSize.height / previewSize.width;
    final radius = (screenWidth(context) - 100) / 2;

    return Scaffold(
      backgroundColor: Colors.white,
      appBar: MyAppbar(title: '人脸识别'),
      body: Stack(
        children: [
          Positioned.fill(child: Container(color: Colors.white)),

          Transform.translate(
            offset: const Offset(0, -100),
            child: Stack(
              children: [
                Center(
                  child: ClipOval(
                    child: AspectRatio(
                      aspectRatio: previewAspect,
                      child: CameraPreview(_cameraController!),
                    ),
                  ),
                ),
                Positioned.fill(
                  child: CustomPaint(
                    painter: _WhiteMaskPainter(radius: radius),
                  ),
                ),
              ],
            ),
          ),

          Align(
            alignment: Alignment.center,
            child: Padding(
              padding: const EdgeInsets.only(top: 250),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Text(
                    _tip,
                    style: const TextStyle(fontSize: 18, color: Colors.black87),
                    textAlign: TextAlign.center,
                  ),
                  const SizedBox(height: 20),
                  if (_isManualMode)
                    CustomButton(text: '拍照/上传', backgroundColor: Colors.blue,onPressed: _captureAndReload,)
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }
}

class _WhiteMaskPainter extends CustomPainter {
  final double radius;
  _WhiteMaskPainter({required this.radius});

  @override
  void paint(Canvas canvas, Size size) {
    canvas.saveLayer(Offset.zero & size, Paint());
    canvas.drawRect(Offset.zero & size, Paint()..color = Colors.white);
    canvas.drawCircle(
      size.center(Offset.zero),
      radius,
      Paint()..blendMode = BlendMode.clear,
    );
    canvas.restore();
  }

  @override
  bool shouldRepaint(covariant CustomPainter old) => false;
}