import 'dart:io';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:google_mlkit_barcode_scanning/google_mlkit_barcode_scanning.dart';
import 'package:provider/provider.dart';

import '../../providers/user_provider.dart';

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

  @override
  State<UpdateScorePage> createState() => _UpdateScorePageState();
}

class _UpdateScorePageState extends State<UpdateScorePage> {
  final TextEditingController _segaIdController = TextEditingController();
  final ImagePicker _picker = ImagePicker();

  bool _isProcessing = false;
  String? _statusMessage;
  File? _selectedImageFile; // 用于预览

  // 条码扫描器 (支持 QR Code, Data Matrix, Aztec 等)
  final BarcodeScanner _barcodeScanner = BarcodeScanner(
    formats: [BarcodeFormat.qrCode, BarcodeFormat.dataMatrix, BarcodeFormat.aztec],
  );

  @override
  void dispose() {
    _segaIdController.dispose();
    _barcodeScanner.close();
    super.dispose();
  }

  // 1. 选择图片并识别二维码
  Future<void> _pickImageAndScan() async {
    try {
      final XFile? pickedFile = await _picker.pickImage(source: ImageSource.gallery);
      if (pickedFile == null) return;

      setState(() {
        _isProcessing = true;
        _statusMessage = "正在识别二维码...";
        _selectedImageFile = File(pickedFile.path);
      });

      // 执行二维码识别
      final inputImage = InputImage.fromFilePath(pickedFile.path);
      final List<Barcode> barcodes = await _barcodeScanner.processImage(inputImage);

      setState(() {
        _isProcessing = false;
      });

      if (barcodes.isNotEmpty) {
        // 取第一个识别到的二维码内容
        final String code = barcodes.first.rawValue ?? "";

        if (code.isNotEmpty) {
          setState(() {
            _segaIdController.text = code;
            _statusMessage = "识别成功: $code";
          });
        } else {
          setState(() {
            _statusMessage = "二维码内容为空";
          });
        }
      } else {
        setState(() {
          _statusMessage = "未在图中发现二维码，请手动输入";
        });
      }

    } catch (e) {
      setState(() {
        _isProcessing = false;
        _statusMessage = "识别失败: $e";
      });
    }
  }

  // 2. 执行隐写上传
  Future<void> _handleUpload() async {
    final segaId = _segaIdController.text.trim();

    if (segaId.isEmpty) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text("请输入或扫描二维码"), backgroundColor: Colors.orange),
      );
      return;
    }

    Uint8List? imageBytes;

    setState(() {
      _isProcessing = true;
      _statusMessage = "正在准备图片...";
    });

    try {
      // 策略：优先使用用户选择的截图作为载体。
      // 如果用户没选图，或者选图后删除了，我们可以下载默认背景图作为载体。
      if (_selectedImageFile != null) {
        imageBytes = await _selectedImageFile!.readAsBytes();
      } else {
        // 下载默认背景图作为隐写载体
        final httpClient = HttpClient();
        final request = await httpClient.getUrl(Uri.parse('https://union.godserver.cn/assets/jpeg/20180621142015_5FmGZ-wYXkyL4y.jpeg'));
        final response = await request.close();

        // 辅助函数：将 HttpClientResponse 转为 Uint8List
        final bytes = <int>[];
        await for (final chunk in response) {
          bytes.addAll(chunk);
        }
        imageBytes = Uint8List.fromList(bytes);
      }

      if (imageBytes == null || imageBytes.isEmpty) {
        throw Exception("图片数据无效");
      }

      setState(() {
        _statusMessage = "正在隐写并上传...";
      });

      // 调用 Provider 上传
      final userProvider = context.read<UserProvider>();
      final result = await userProvider.uploadStegImage(imageBytes, segaId: segaId);

      setState(() {
        _isProcessing = false;
        _statusMessage = "上传成功!";
      });

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text("上传成功: ${result['msg']}"), backgroundColor: Colors.green),
        );
        // 可选：清空表单
        // _segaIdController.clear();
        // _selectedImageFile = null;
      }

    } catch (e) {
      setState(() {
        _isProcessing = false;
        _statusMessage = "上传失败: $e";
      });
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text("错误: $e"), backgroundColor: Colors.red),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        fit: StackFit.expand,
        children: [
          // 1. 背景图片
          Image.network(
            'https://union.godserver.cn/assets/jpeg/20180621142015_5FmGZ-wYXkyL4y.jpeg',
            fit: BoxFit.cover,
            loadingBuilder: (context, child, loadingProgress) {
              if (loadingProgress == null) return child;
              return Container(color: Colors.black);
            },
            errorBuilder: (context, error, stackTrace) {
              return Container(color: Colors.grey[900]);
            },
          ),

          // 2. 深色遮罩
          Container(color: Colors.black.withOpacity(0.7)),

          // 3. 主体内容
          SafeArea(
            child: Center(
              child: SingleChildScrollView(
                padding: const EdgeInsets.all(24.0),
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    // 标题
                    const Text(
                      "更新成绩 / 二维码",
                      style: TextStyle(
                        fontSize: 24,
                        fontWeight: FontWeight.bold,
                        color: Colors.white,
                      ),
                    ),
                    const SizedBox(height: 30),

                    // 卡片容器
                    Container(
                      padding: const EdgeInsets.all(20),
                      decoration: BoxDecoration(
                        color: Colors.white.withOpacity(0.15),
                        borderRadius: BorderRadius.circular(16),
                        border: Border.all(color: Colors.white.withOpacity(0.2)),
                      ),
                      child: Column(
                        children: [
                          // 输入框
                          TextField(
                            controller: _segaIdController,
                            style: const TextStyle(color: Colors.white),
                            decoration: InputDecoration(
                              labelText: "Sega ID / 二维码内容",
                              labelStyle: const TextStyle(color: Colors.white70),
                              hintText: "手动输入或点击下方按钮识别",
                              hintStyle: const TextStyle(color: Colors.white38),
                              prefixIcon: const Icon(Icons.qr_code, color: Colors.white70),
                              enabledBorder: OutlineInputBorder(
                                borderSide: const BorderSide(color: Colors.white38),
                                borderRadius: BorderRadius.circular(12),
                              ),
                              focusedBorder: OutlineInputBorder(
                                borderSide: const BorderSide(color: Colors.white),
                                borderRadius: BorderRadius.circular(12),
                              ),
                            ),
                          ),

                          const SizedBox(height: 20),

                          // 图片预览区域 (如果有)
                          if (_selectedImageFile != null)
                            ClipRRect(
                              borderRadius: BorderRadius.circular(8),
                              child: Image.file(
                                _selectedImageFile!,
                                height: 150,
                                fit: BoxFit.contain,
                              ),
                            ),

                          if (_selectedImageFile != null) const SizedBox(height: 15),

                          // 操作按钮组
                          Row(
                            children: [
                              // 识别二维码按钮
                              Expanded(
                                child: ElevatedButton.icon(
                                  onPressed: _isProcessing ? null : _pickImageAndScan,
                                  icon: const Icon(Icons.camera_alt),
                                  label: const Text("识别截图"),
                                  style: ElevatedButton.styleFrom(
                                    backgroundColor: Colors.blueAccent,
                                    foregroundColor: Colors.white,
                                    padding: const EdgeInsets.symmetric(vertical: 12),
                                    shape: RoundedRectangleBorder(
                                      borderRadius: BorderRadius.circular(8),
                                    ),
                                  ),
                                ),
                              ),

                              const SizedBox(width: 10),

                              // 上传按钮
                              Expanded(
                                flex: 1,
                                child: ElevatedButton.icon(
                                  onPressed: _isProcessing ? null : _handleUpload,
                                  icon: _isProcessing
                                      ? const SizedBox(
                                    width: 16, height: 16,
                                    child: CircularProgressIndicator(strokeWidth: 2, color: Colors.white),
                                  )
                                      : const Icon(Icons.cloud_upload),
                                  label: Text(_isProcessing ? "处理中..." : "上传"),
                                  style: ElevatedButton.styleFrom(
                                    backgroundColor: Colors.green,
                                    foregroundColor: Colors.white,
                                    padding: const EdgeInsets.symmetric(vertical: 12),
                                    shape: RoundedRectangleBorder(
                                      borderRadius: BorderRadius.circular(8),
                                    ),
                                  ),
                                ),
                              ),
                            ],
                          ),
                        ],
                      ),
                    ),

                    // 状态提示
                    if (_statusMessage != null)
                      Padding(
                        padding: const EdgeInsets.only(top: 20),
                        child: Text(
                          _statusMessage!,
                          style: TextStyle(
                            color: _statusMessage!.contains("失败") || _statusMessage!.contains("错误")
                                ? Colors.redAccent
                                : Colors.white70,
                            fontSize: 14,
                          ),
                          textAlign: TextAlign.center,
                        ),
                      ),
                  ],
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}