import 'package:flutter/material.dart';
import 'package:camera/camera.dart';
import 'package:provider/provider.dart';
import 'package:permission_handler/permission_handler.dart';
import '../services/camera_service.dart';
import '../services/api_service.dart';

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

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

class _CameraScreenState extends State<CameraScreen> {
  late CameraService _cameraService;
  late ApiService _apiService;
  bool _isProcessing = false;
  String _statusMessage = '准备就绪';
  int _frameCount = 0;
  int _uploadCount = 0;

  @override
  void initState() {
    super.initState();
    _cameraService = CameraService();
    _apiService = ApiService();
    _initializeCamera();
  }

  Future<void> _initializeCamera() async {
    // 请求相机权限
    final status = await Permission.camera.request();
    if (!status.isGranted) {
      setState(() {
        _statusMessage = '相机权限被拒绝';
      });
      return;
    }

    // 初始化相机
    await _cameraService.initialize();
    if (mounted) {
      setState(() {
        _statusMessage = '相机已就绪';
      });
    }
  }

  /// 开始实时传输
  void _startStreaming() {
    if (_cameraService.isStreaming) return;

    setState(() {
      _statusMessage = '实时传输中...';
      _frameCount = 0;
      _uploadCount = 0;
    });

    _cameraService.startStreaming((imageBytes) async {
      setState(() {
        _frameCount++;
      });

      // 上传到后端（异步，不阻塞捕获）
      _uploadToBackend(imageBytes);
    });
  }

  /// 停止实时传输
  void _stopStreaming() {
    _cameraService.stopStreaming();
    setState(() {
      _statusMessage = '已停止传输';
    });
  }

  /// 上传图像到后端
  Future<void> _uploadToBackend(imageBytes) async {
    if (_isProcessing) return; // 防止并发上传

    _isProcessing = true;

    try {
      // 上传图像
      final result = await _apiService.uploadImage(imageBytes);

      setState(() {
        _uploadCount++;
        _statusMessage = '已上传 $_uploadCount 帧';
      });

      print('上传成功: ${result['image_id']}');
    } catch (e) {
      print('上传失败: $e');
      setState(() {
        _statusMessage = '上传失败: $e';
      });
    } finally {
      _isProcessing = false;
    }
  }

  /// 拍摄单张照片并分析
  Future<void> _captureAndAnalyze() async {
    setState(() {
      _statusMessage = '正在拍照...';
    });

    final imageBytes = await _cameraService.takePicture();
    if (imageBytes == null) {
      setState(() {
        _statusMessage = '拍照失败';
      });
      return;
    }

    setState(() {
      _statusMessage = '正在分析...';
    });

    try {
      // 上传并分析
      final result = await _apiService.uploadAndAnalyze(imageBytes);

      setState(() {
        _statusMessage = '分析完成';
      });

      // 显示结果
      _showAnalysisResult(result);
    } catch (e) {
      setState(() {
        _statusMessage = '分析失败: $e';
      });
    }
  }

  /// 显示分析结果
  void _showAnalysisResult(Map<String, dynamic> result) {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('分析结果'),
        content: SingleChildScrollView(
          child: Text(result.toString()),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('关闭'),
          ),
        ],
      ),
    );
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('实时相机'),
        backgroundColor: Colors.black,
      ),
      body: _cameraService.isInitialized
          ? _buildCameraView()
          : const Center(child: CircularProgressIndicator()),
    );
  }

  Widget _buildCameraView() {
    return Stack(
      children: [
        // 相机预览
        Positioned.fill(
          child: CameraPreview(_cameraService.controller!),
        ),

        // 状态信息
        Positioned(
          top: 16,
          left: 16,
          right: 16,
          child: Container(
            padding: const EdgeInsets.all(12),
            decoration: BoxDecoration(
              color: Colors.black.withOpacity(0.7),
              borderRadius: BorderRadius.circular(8),
            ),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  _statusMessage,
                  style: const TextStyle(
                    color: Colors.white,
                    fontSize: 16,
                    fontWeight: FontWeight.bold,
                  ),
                ),
                const SizedBox(height: 4),
                Text(
                  '捕获帧数: $_frameCount | 上传帧数: $_uploadCount',
                  style: const TextStyle(
                    color: Colors.white70,
                    fontSize: 14,
                  ),
                ),
              ],
            ),
          ),
        ),

        // 控制按钮
        Positioned(
          bottom: 32,
          left: 0,
          right: 0,
          child: Row(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            children: [
              // 拍照并分析按钮
              _buildControlButton(
                icon: Icons.camera_alt,
                label: '拍照分析',
                onPressed: _captureAndAnalyze,
                color: Colors.blue,
              ),

              // 开始/停止实时传输按钮
              _buildControlButton(
                icon: _cameraService.isStreaming ? Icons.stop : Icons.play_arrow,
                label: _cameraService.isStreaming ? '停止传输' : '开始传输',
                onPressed: _cameraService.isStreaming ? _stopStreaming : _startStreaming,
                color: _cameraService.isStreaming ? Colors.red : Colors.green,
              ),

              // 切换摄像头按钮
              _buildControlButton(
                icon: Icons.flip_camera_android,
                label: '切换',
                onPressed: () => _cameraService.switchCamera(),
                color: Colors.orange,
              ),
            ],
          ),
        ),
      ],
    );
  }

  Widget _buildControlButton({
    required IconData icon,
    required String label,
    required VoidCallback onPressed,
    required Color color,
  }) {
    return Column(
      mainAxisSize: MainAxisSize.min,
      children: [
        FloatingActionButton(
          onPressed: onPressed,
          backgroundColor: color,
          child: Icon(icon, size: 32),
        ),
        const SizedBox(height: 8),
        Text(
          label,
          style: const TextStyle(
            color: Colors.white,
            fontSize: 12,
            fontWeight: FontWeight.bold,
            shadows: [
              Shadow(
                color: Colors.black,
                blurRadius: 4,
              ),
            ],
          ),
        ),
      ],
    );
  }
}