import 'dart:async';
import 'dart:io';
import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart' show kIsWeb;
import 'package:image_picker/image_picker.dart';
import 'package:gal/gal.dart';
import 'package:path_provider/path_provider.dart';
import 'package:path/path.dart' as path;
import 'package:permission_handler/permission_handler.dart';
import 'package:camera_app/services/yolo_service.dart';
import 'package:camera_app/screens/result_screen.dart';

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

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

class _CameraScreenState extends State<CameraScreen> {
  CameraController? _controller;
  List<CameraDescription>? _cameras;
  bool _isInitialized = false;
  bool _isCapturing = false;
  int _photoCount = 0;
  Timer? _timer;
  List<String> _savedPhotoPaths = [];
  bool _isWebOrDesktop = false;
  final YOLOService _yoloService = YOLOService();

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

  Future<void> _initializeCamera() async {
    try {
      // Web 和桌面平台使用 image_picker
      if (kIsWeb || (!Platform.isAndroid && !Platform.isIOS)) {
        if (mounted) {
          setState(() {
            _isWebOrDesktop = true;
            _isInitialized = true; // Web/桌面平台直接显示界面
          });
        }
        return;
      }

      // 移动平台使用 camera 包
      await _requestPermissions();

      _cameras = await availableCameras();
      if (_cameras == null || _cameras!.isEmpty) {
        _showError('未找到可用的相机');
        return;
      }

      _controller = CameraController(
        _cameras![0],
        ResolutionPreset.high,
        enableAudio: false,
      );

      await _controller!.initialize();

      if (mounted) {
        setState(() {
          _isInitialized = true;
        });
      }
    } catch (e) {
      _showError('初始化相机失败: $e');
    }
  }

  Future<void> _requestPermissions() async {
    if (kIsWeb || (!Platform.isAndroid && !Platform.isIOS)) {
      return; // Web/桌面平台权限由浏览器/系统处理
    }

    final cameraStatus = await Permission.camera.request();
    if (!cameraStatus.isGranted) {
      _showError('需要相机权限才能使用此功能');
      return;
    }

    if (Platform.isAndroid) {
      final photosStatus = await Permission.photos.request();
      if (photosStatus.isDenied || photosStatus.isPermanentlyDenied) {
        final storageStatus = await Permission.storage.request();
        if (!storageStatus.isGranted) {
          _showError('需要存储权限才能保存图片');
          return;
        }
      }
    } else if (Platform.isIOS) {
      final photosStatus = await Permission.photos.request();
      if (!photosStatus.isGranted) {
        _showError('需要照片权限才能保存图片');
        return;
      }
    }
  }

  Future<void> _startCapturing() async {
    if (_isWebOrDesktop) {
      _showError('Web/桌面平台不支持自动连续拍照，请使用移动设备');
      return;
    }

    // 移动平台：自动拍照模式
    if (!_isInitialized || _controller == null || !_controller!.value.isInitialized) {
      _showError('相机未初始化');
      return;
    }

    setState(() {
      _isCapturing = true;
      _photoCount = 0;
      _savedPhotoPaths.clear();
    });

    // 立即拍摄第一张
    await _takePhoto();

    // 然后每2秒拍摄一张，直到点击停止
    _timer = Timer.periodic(const Duration(seconds: 2), (timer) async {
      if (_isCapturing) {
        await _takePhoto();
      } else {
        timer.cancel();
      }
    });
  }

  Future<void> _stopCapturing() async {
    setState(() {
      _isCapturing = false;
    });
    _timer?.cancel();

    if (_savedPhotoPaths.isEmpty) {
      _showError('没有拍摄照片');
      return;
    }

    // 显示分析中对话框
    if (!mounted) return;
    
    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (BuildContext context) {
        return const AlertDialog(
          content: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              CircularProgressIndicator(),
              SizedBox(height: 16),
              Text('正在分析照片...'),
            ],
          ),
        );
      },
    );

    try {
      // 使用YOLO分析照片
      final analysisResults = await _yoloService.analyzeImages(_savedPhotoPaths);

      if (!mounted) return;
      
      Navigator.of(context).pop(); // 关闭分析中对话框

      // 导航到结果页面
      Navigator.of(context).pushReplacement(
        MaterialPageRoute(
          builder: (context) => ResultScreen(
            photoPaths: _savedPhotoPaths,
            analysisResults: analysisResults,
          ),
        ),
      );
    } catch (e) {
      if (!mounted) return;
      
      Navigator.of(context).pop(); // 关闭分析中对话框
      _showError('分析照片失败: $e');
    }
  }

  Future<void> _takePhoto() async {
    if (_controller == null || !_controller!.value.isInitialized) {
      return;
    }

    try {
      final XFile photo = await _controller!.takePicture();
      await _savePhoto(photo.path);

      if (mounted) {
        setState(() {
          _photoCount++;
        });
      }
    } catch (e) {
      if (mounted) {
        _showError('拍照失败: $e');
      }
    }
  }

  Future<void> _savePhoto(String photoPath) async {
    try {
      if (!kIsWeb && (Platform.isAndroid || Platform.isIOS)) {
        // 移动平台：保存到相册
        await Gal.putImage(photoPath);
      } else {
        // Web/桌面平台：保存到下载目录
        final appDir = await getApplicationDocumentsDirectory();
        final fileName = 'photo_${DateTime.now().millisecondsSinceEpoch}.jpg';
        final savedPath = path.join(appDir.path, fileName);
        await File(photoPath).copy(savedPath);
      }
      _savedPhotoPaths.add(photoPath);
    } catch (e) {
      // 保存失败不影响流程
      _savedPhotoPaths.add(photoPath);
    }
  }

  void _showError(String message) {
    if (mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(message),
          backgroundColor: Colors.red,
        ),
      );
    }
  }

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

  @override
  Widget build(BuildContext context) {
    if (!_isInitialized) {
      return Scaffold(
        backgroundColor: Colors.black,
        body: const Center(
          child: CircularProgressIndicator(color: Colors.white),
        ),
      );
    }

    // Web/桌面平台界面
    if (_isWebOrDesktop) {
      return Scaffold(
        backgroundColor: Colors.black,
        body: Center(
          child: Padding(
            padding: const EdgeInsets.all(24.0),
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                const Icon(
                  Icons.camera_alt,
                  size: 100,
                  color: Colors.white,
                ),
                const SizedBox(height: 32),
                Text(
                  '$_photoCount 张',
                  style: const TextStyle(
                    color: Colors.white,
                    fontSize: 48,
                    fontWeight: FontWeight.bold,
                  ),
                ),
                const SizedBox(height: 16),
                const Text(
                  'Web/桌面平台不支持自动连续拍照',
                  style: TextStyle(
                    color: Colors.white70,
                    fontSize: 18,
                  ),
                  textAlign: TextAlign.center,
                ),
                const SizedBox(height: 48),
                IconButton(
                  icon: const Icon(Icons.arrow_back, color: Colors.white),
                  onPressed: () => Navigator.of(context).pop(),
                  tooltip: '返回',
                ),
              ],
            ),
          ),
        ),
      );
    }

    // 移动平台：显示相机预览
    if (_controller == null || !_controller!.value.isInitialized) {
      return Scaffold(
        backgroundColor: Colors.black,
        body: const Center(
          child: Text(
            '相机初始化中...',
            style: TextStyle(color: Colors.white),
          ),
        ),
      );
    }

    return Scaffold(
      backgroundColor: Colors.black,
      body: Stack(
        children: [
          SizedBox.expand(child: CameraPreview(_controller!)),

          SafeArea(
            child: Container(
              padding: const EdgeInsets.all(16),
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment.topCenter,
                  end: Alignment.bottomCenter,
                  colors: [
                    Colors.black.withOpacity(0.7),
                    Colors.transparent,
                  ],
                ),
              ),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: [
                  IconButton(
                    icon: const Icon(Icons.arrow_back, color: Colors.white),
                    onPressed: () {
                      if (_isCapturing) {
                        _stopCapturing();
                      }
                      Navigator.of(context).pop();
                    },
                  ),
                  if (_isCapturing)
                    Container(
                      padding: const EdgeInsets.symmetric(
                        horizontal: 16,
                        vertical: 8,
                      ),
                      decoration: BoxDecoration(
                        color: Colors.red.withOpacity(0.8),
                        borderRadius: BorderRadius.circular(20),
                      ),
                      child: Row(
                        children: [
                          Container(
                            width: 12,
                            height: 12,
                            decoration: const BoxDecoration(
                              color: Colors.white,
                              shape: BoxShape.circle,
                            ),
                          ),
                          const SizedBox(width: 8),
                          Text(
                            '$_photoCount 张',
                            style: const TextStyle(
                              color: Colors.white,
                              fontSize: 16,
                              fontWeight: FontWeight.bold,
                            ),
                          ),
                        ],
                      ),
                    ),
                ],
              ),
            ),
          ),

          Align(
            alignment: Alignment.bottomCenter,
            child: Container(
              padding: const EdgeInsets.all(32),
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment.bottomCenter,
                  end: Alignment.topCenter,
                  colors: [
                    Colors.black.withOpacity(0.7),
                    Colors.transparent,
                  ],
                ),
              ),
              child: _isCapturing
                  ? Column(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        ElevatedButton.icon(
                          onPressed: _stopCapturing,
                          icon: const Icon(Icons.stop, size: 28),
                          label: const Text(
                            '停止拍照',
                            style: TextStyle(fontSize: 18),
                          ),
                          style: ElevatedButton.styleFrom(
                            backgroundColor: Colors.red,
                            foregroundColor: Colors.white,
                            padding: const EdgeInsets.symmetric(
                              horizontal: 32,
                              vertical: 16,
                            ),
                            shape: RoundedRectangleBorder(
                              borderRadius: BorderRadius.circular(30),
                            ),
                          ),
                        ),
                        const SizedBox(height: 16),
                        Text(
                          '已拍摄 $_photoCount 张照片',
                          style: const TextStyle(
                            color: Colors.white,
                            fontSize: 16,
                          ),
                        ),
                      ],
                    )
                  : ElevatedButton.icon(
                      onPressed: _startCapturing,
                      icon: const Icon(Icons.camera_alt, size: 28),
                      label: const Text(
                        '开始拍照',
                        style: TextStyle(fontSize: 18),
                      ),
                      style: ElevatedButton.styleFrom(
                        backgroundColor: Colors.white,
                        foregroundColor: Colors.black,
                        padding: const EdgeInsets.symmetric(
                          horizontal: 32,
                          vertical: 16,
                        ),
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(30),
                        ),
                      ),
                    ),
            ),
          ),
        ],
      ),
    );
  }
}