import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:go_router/go_router.dart';
import 'package:image_picker/image_picker.dart';
import 'package:mobile_scanner/mobile_scanner.dart';
import '../../../../core/di/injection_container.dart';
import '../../../../core/storage/storage_keys.dart';
import '../../../../routes/route_paths.dart';
import '../providers/auth_provider.dart';

/// 向导页数据模型
class GuidePageData {
  final String? imagePath;
  final String title;
  final String subtitle;
  final Widget? customContent;

  const GuidePageData({
    this.imagePath,
    required this.title,
    required this.subtitle,
    this.customContent,
  });
}

/// 向导页面 - 用户首次打开应用时展示
/// 支持左右滑动切换页面
class GuidePage extends ConsumerStatefulWidget {
  /// 初始页面索引（0-4，默认为0）
  final int initialPage;

  const GuidePage({super.key, this.initialPage = 0});

  @override
  ConsumerState<GuidePage> createState() => _GuidePageState();
}

class _GuidePageState extends ConsumerState<GuidePage> {
  late final PageController _pageController;
  late int _currentPage;

  @override
  void initState() {
    super.initState();
    // 使用传入的初始页面索引
    _currentPage = widget.initialPage.clamp(0, 4);
    _pageController = PageController(initialPage: _currentPage);
    // 延迟到 build 后获取屏幕信息
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _logScreenInfo();
    });
  }

  /// 打印屏幕信息用于调试
  void _logScreenInfo() {
    final mediaQuery = MediaQuery.of(context);
    final screenSize = mediaQuery.size;
    final devicePixelRatio = mediaQuery.devicePixelRatio;
    final physicalSize = screenSize * devicePixelRatio;

    debugPrint('[GuidePage] ========== 屏幕信息 ==========');
    debugPrint('[GuidePage] 逻辑分辨率: ${screenSize.width.toStringAsFixed(1)} x ${screenSize.height.toStringAsFixed(1)}');
    debugPrint('[GuidePage] 设备像素比: $devicePixelRatio');
    debugPrint('[GuidePage] 物理分辨率: ${physicalSize.width.toStringAsFixed(0)} x ${physicalSize.height.toStringAsFixed(0)}');
    debugPrint('[GuidePage] 屏幕宽高比: ${(screenSize.width / screenSize.height).toStringAsFixed(3)} (${screenSize.width.toStringAsFixed(0)}:${screenSize.height.toStringAsFixed(0)})');
    debugPrint('[GuidePage] 图片设计比例: 0.5625 (1080:1920 = 9:16)');
    debugPrint('[GuidePage] ================================');
  }

  // 向导页1-5的数据 (第5页为欢迎加入页)
  // 支持 png、jpg、webp 等格式
  final List<GuidePageData> _guidePages = const [
    GuidePageData(
      imagePath: 'assets/images/guide_1.jpg',
      title: '认种一棵榴莲树\n拥有真实RWA资产',
      subtitle: '绑定真实果园20年收益，让区块链与农业完美结合',
    ),
    GuidePageData(
      imagePath: 'assets/images/guide_2.jpg',
      title: '认种即可开启算力\n自动挖矿持续收益',
      subtitle: '每一棵树都对应真实资产注入，为算力提供真实价值支撑',
    ),
    GuidePageData(
      imagePath: 'assets/images/guide_3.jpg',
      title: '分享链接\n获得团队算力与收益',
      subtitle: '真实认种数据透明可信 · 团队越大算力越强',
    ),
    GuidePageData(
      imagePath: 'assets/images/guide_4.jpg',
      title: 'MPC多方安全\n所有地址与收益可审计',
      subtitle: '你的资产 · 安全透明 · 不可被篡改',
    ),
    GuidePageData(
      imagePath: 'assets/images/guide_5.jpg',
      title: '欢迎加入',
      subtitle: '创建账号前的最后一步 · 请选择是否有推荐人',
    ),
  ];

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

  void _onPageChanged(int page) {
    setState(() {
      _currentPage = page;
    });
  }

  void _goToNextPage() {
    if (_currentPage < 4) {
      _pageController.nextPage(
        duration: const Duration(milliseconds: 300),
        curve: Curves.easeInOut,
      );
    }
  }

  void _goToOnboarding() async {
    // 标记已查看向导页
    await ref.read(authProvider.notifier).markGuideAsSeen();
    if (!mounted) return;
    context.go(RoutePaths.onboarding);
  }

  /// 退出应用
  void _exitApp() {
    SystemNavigator.pop();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      body: PageView.builder(
        controller: _pageController,
        onPageChanged: _onPageChanged,
        itemCount: 5, // 4个介绍页 + 1个欢迎加入页
        itemBuilder: (context, index) {
          if (index < 4) {
            return _buildGuidePage(_guidePages[index], index);
          } else {
            return _buildWelcomePage();
          }
        },
      ),
    );
  }

  /// 构建向导页 (页面1-4) - 全屏背景图片，无文字
  /// 使用 BoxFit.cover 填满屏幕，保持宽高比（会裁剪超出部分）
  Widget _buildGuidePage(GuidePageData data, int index) {
    debugPrint('[GuidePage] _buildGuidePage() - 页面 ${index + 1}, 图片: ${data.imagePath}');
    return Stack(
      fit: StackFit.expand,
      children: [
        // 全屏背景图片 - 使用 cover 填满屏幕
        if (data.imagePath != null)
          Image.asset(
            data.imagePath!,
            fit: BoxFit.cover,
            width: double.infinity,
            height: double.infinity,
            errorBuilder: (context, error, stackTrace) {
              debugPrint('[GuidePage] 页面 ${index + 1} 图片加载失败: $error');
              return Container(
                color: const Color(0xFFFFF8E7),
                child: _buildPlaceholderImage(index),
              );
            },
          )
        else
          Container(
            color: const Color(0xFFFFF8E7),
            child: _buildPlaceholderImage(index),
          ),
        // 底部页面指示器 - 使用 SafeArea 避免被系统 UI 遮挡
        Positioned(
          left: 0,
          right: 0,
          bottom: 0,
          child: SafeArea(
            child: Padding(
              padding: EdgeInsets.only(bottom: 40.h),
              child: _buildPageIndicator(),
            ),
          ),
        ),
      ],
    );
  }

  /// 构建占位图片
  Widget _buildPlaceholderImage(int index) {
    final icons = [
      Icons.nature,
      Icons.memory,
      Icons.people,
      Icons.security,
    ];
    final colors = [
      const Color(0xFF8BC34A),
      const Color(0xFFD4AF37),
      const Color(0xFFFF9800),
      const Color(0xFF2196F3),
    ];

    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Icon(
            icons[index],
            size: 80.sp,
            color: colors[index],
          ),
          SizedBox(height: 16.h),
          Text(
            '向导页 ${index + 1}',
            style: TextStyle(
              fontSize: 16.sp,
              color: const Color(0xFF57534E),
            ),
          ),
        ],
      ),
    );
  }

  /// 构建欢迎加入页面 (页面5)
  Widget _buildWelcomePage() {
    return _WelcomePageContent(
      onNext: _goToOnboarding,
      onExit: _exitApp, // 退出整个应用
      backgroundImage: _guidePages[4].imagePath,
      pageIndicator: _buildPageIndicator(),
    );
  }

  /// 构建页面指示器 (所有页面都使用白色系，因为都有背景图)
  Widget _buildPageIndicator() {
    return Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: List.generate(5, (index) {
        final isActive = index == _currentPage;
        return Container(
          width: 8.w,
          height: 8.w,
          margin: EdgeInsets.symmetric(horizontal: 4.w),
          decoration: BoxDecoration(
            shape: BoxShape.circle,
            color: isActive
                ? Colors.white
                : Colors.white.withValues(alpha: 0.4),
          ),
        );
      }),
    );
  }
}

/// 欢迎加入页面内容 (第5页)
class _WelcomePageContent extends ConsumerStatefulWidget {
  final VoidCallback onNext;
  final VoidCallback onExit;
  final String? backgroundImage;
  final Widget pageIndicator;

  const _WelcomePageContent({
    required this.onNext,
    required this.onExit,
    this.backgroundImage,
    required this.pageIndicator,
  });

  @override
  ConsumerState<_WelcomePageContent> createState() => _WelcomePageContentState();
}

class _WelcomePageContentState extends ConsumerState<_WelcomePageContent> {
  bool _hasReferrer = true;
  final TextEditingController _referralCodeController = TextEditingController();

  @override
  void initState() {
    super.initState();
    // 监听输入框变化以更新按钮状态
    _referralCodeController.addListener(_onReferralCodeChanged);
  }

  @override
  void dispose() {
    _referralCodeController.removeListener(_onReferralCodeChanged);
    _referralCodeController.dispose();
    super.dispose();
  }

  /// 输入框内容变化时刷新UI
  void _onReferralCodeChanged() {
    setState(() {});
  }

  /// 验证推荐码是否有效
  /// 支持: 纯推荐码(至少3个字符) 或 合法URL
  bool _isValidReferralCode(String code) {
    final trimmed = code.trim();
    if (trimmed.isEmpty) return false;

    // 如果是URL格式，检查是否能解析
    if (trimmed.startsWith('http://') || trimmed.startsWith('https://')) {
      try {
        final uri = Uri.parse(trimmed);
        // URL必须有路径或查询参数
        return uri.pathSegments.isNotEmpty || uri.queryParameters.isNotEmpty;
      } catch (e) {
        return false;
      }
    }

    // 纯推荐码至少3个字符
    return trimmed.length >= 3;
  }

  /// 判断按钮是否可点击
  bool get _canProceed {
    // 如果选择"没有推荐人"，按钮可点击
    if (!_hasReferrer) return true;

    // 如果选择"有推荐人"，需要填写有效的推荐码
    return _isValidReferralCode(_referralCodeController.text);
  }

  /// 导入助记词恢复账号
  void _importMnemonic() {
    debugPrint('[GuidePage] _importMnemonic - 跳转到导入助记词页面');
    context.push(RoutePaths.importMnemonic);
  }

  /// 保存推荐码并继续下一步
  Future<void> _saveReferralCodeAndProceed() async {
    if (!_canProceed) return;

    // 如果有推荐人且推荐码有效，保存到本地存储
    if (_hasReferrer && _referralCodeController.text.trim().isNotEmpty) {
      final secureStorage = ref.read(secureStorageProvider);
      await secureStorage.write(
        key: StorageKeys.inviterReferralCode,
        value: _referralCodeController.text.trim(),
      );
      debugPrint('[GuidePage] 保存邀请人推荐码: ${_referralCodeController.text.trim()}');
    }

    // 调用下一步回调
    widget.onNext();
  }

  /// 打开二维码扫描页面
  Future<void> _openQrScanner() async {
    final result = await Navigator.of(context).push<String>(
      MaterialPageRoute(
        builder: (context) => const _QrScannerPage(),
      ),
    );
    if (result != null && result.isNotEmpty) {
      // 从扫描结果中提取推荐码
      final referralCode = _extractReferralCode(result);
      setState(() {
        _referralCodeController.text = referralCode;
        _hasReferrer = true;
      });
    }
  }

  /// 从扫描结果中提取推荐码
  /// 支持以下格式:
  /// - 查询参数: https://app.rwadurian.com/share?ref=ABC123 -> ABC123
  /// - 路径格式: https://app.rwadurian.com/r/ABC123 -> ABC123
  /// - 短链: https://rwa.link/ABC123 -> ABC123
  /// - 纯推荐码: ABC123 -> ABC123
  String _extractReferralCode(String scannedData) {
    // 去除首尾空格
    String data = scannedData.trim();

    // 如果是 URL，尝试提取推荐码
    if (data.startsWith('http://') || data.startsWith('https://')) {
      try {
        final uri = Uri.parse(data);

        // 优先从查询参数中提取 (如 ?ref=ABC123 或 ?code=ABC123)
        final refCode = uri.queryParameters['ref'] ??
                        uri.queryParameters['code'] ??
                        uri.queryParameters['referral'];
        if (refCode != null && refCode.isNotEmpty) {
          return refCode;
        }

        // 其次从路径中提取 (如 /r/ABC123 或 /ABC123)
        final pathSegments = uri.pathSegments;
        if (pathSegments.isNotEmpty) {
          // 取最后一个路径段作为推荐码
          final lastSegment = pathSegments.last;
          // 排除常见的非推荐码路径段
          const excludedSegments = ['share', 'invite', 'r', 'ref', 'referral'];
          if (lastSegment.isNotEmpty && !excludedSegments.contains(lastSegment.toLowerCase())) {
            return lastSegment;
          }
          // 如果最后一段是排除项且有倒数第二段，检查倒数第二段
          if (pathSegments.length >= 2) {
            final secondLastSegment = pathSegments[pathSegments.length - 2];
            if (secondLastSegment.isNotEmpty && !excludedSegments.contains(secondLastSegment.toLowerCase())) {
              return secondLastSegment;
            }
          }
        }
      } catch (e) {
        // URL 解析失败，返回原始数据
        debugPrint('URL 解析失败: $e');
      }
    }

    // 不是 URL 或解析失败，返回原始数据
    return data;
  }

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () => FocusScope.of(context).unfocus(),
      child: Stack(
        fit: StackFit.expand,
        children: [
          // 全屏背景图片 - 使用 cover 填满屏幕
          if (widget.backgroundImage != null)
            Image.asset(
              widget.backgroundImage!,
              fit: BoxFit.cover,
              width: double.infinity,
              height: double.infinity,
              errorBuilder: (context, error, stackTrace) {
                return Container(
                  color: const Color(0xFFFFF8E7),
                );
              },
            )
          else
            Container(
              color: const Color(0xFFFFF8E7),
            ),
          // 半透明遮罩，让内容更清晰
          Container(
            decoration: BoxDecoration(
              gradient: LinearGradient(
                begin: Alignment.topCenter,
                end: Alignment.bottomCenter,
                colors: [
                  Colors.black.withValues(alpha: 0.3),
                  Colors.black.withValues(alpha: 0.6),
                ],
              ),
            ),
          ),
          // 内容区域
          SafeArea(
            child: LayoutBuilder(
              builder: (context, constraints) {
                return SingleChildScrollView(
                  child: ConstrainedBox(
                    constraints: BoxConstraints(
                      minHeight: constraints.maxHeight,
                    ),
                    child: IntrinsicHeight(
                      child: Padding(
                        padding: EdgeInsets.symmetric(horizontal: 24.w),
                        child: Column(
                          children: [
                            // 退出按钮
                            Align(
                              alignment: Alignment.topRight,
                              child: Padding(
                                padding: EdgeInsets.only(top: 16.h),
                                child: GestureDetector(
                                  onTap: widget.onExit,
                                  child: Text(
                                    '退出',
                                    style: TextStyle(
                                      fontSize: 14.sp,
                                      color: Colors.white.withValues(alpha: 0.8),
                                    ),
                                  ),
                                ),
                              ),
                            ),
                            SizedBox(height: 60.h),
                            // 欢迎标题
                            Text(
                              '欢迎加入',
                              style: TextStyle(
                                fontSize: 28.sp,
                                fontWeight: FontWeight.w700,
                                height: 1.33,
                                color: Colors.white,
                                shadows: [
                                  Shadow(
                                    color: Colors.black.withValues(alpha: 0.5),
                                    blurRadius: 4,
                                  ),
                                ],
                              ),
                            ),
                            SizedBox(height: 12.h),
                            // 副标题
                            Text(
                              '创建账号前的最后一步 · 请选择是否有推荐人',
                              style: TextStyle(
                                fontSize: 14.sp,
                                height: 1.43,
                                color: Colors.white.withValues(alpha: 0.9),
                                shadows: [
                                  Shadow(
                                    color: Colors.black.withValues(alpha: 0.5),
                                    blurRadius: 4,
                                  ),
                                ],
                              ),
                            ),
                            SizedBox(height: 48.h),
                            // 选项区域 (透明背景)
                            _buildReferrerOptions(),
                            const Spacer(),
                            // 页面指示器
                            widget.pageIndicator,
                            SizedBox(height: 24.h),
                            // 下一步按钮
                            GestureDetector(
                              onTap: _canProceed ? _saveReferralCodeAndProceed : null,
                              child: Container(
                                width: double.infinity,
                                padding: EdgeInsets.symmetric(vertical: 16.h),
                                decoration: BoxDecoration(
                                  color: _canProceed
                                      ? const Color(0xFFD4A84B)
                                      : Colors.white.withValues(alpha: 0.3),
                                  borderRadius: BorderRadius.circular(12.r),
                                ),
                                child: Text(
                                  '下一步 (创建账号)',
                                  style: TextStyle(
                                    fontSize: 16.sp,
                                    fontWeight: FontWeight.w600,
                                    height: 1.5,
                                    color: _canProceed
                                        ? Colors.white
                                        : Colors.white.withValues(alpha: 0.6),
                                  ),
                                  textAlign: TextAlign.center,
                                ),
                              ),
                            ),
                            SizedBox(height: 32.h),
                          ],
                        ),
                      ),
                    ),
                  ),
                );
              },
            ),
          ),
        ],
      ),
    );
  }

  /// 构建推荐人选项 (透明背景，白色文字)
  Widget _buildReferrerOptions() {
    return Column(
      children: [
        // 有推荐人选项
        GestureDetector(
          onTap: () {
            setState(() {
              _hasReferrer = true;
            });
          },
          child: Row(
            children: [
              _buildRadio(_hasReferrer),
              SizedBox(width: 12.w),
              Text(
                '我有推荐人',
                style: TextStyle(
                  fontSize: 16.sp,
                  height: 1.5,
                  color: Colors.white,
                  shadows: [
                    Shadow(
                      color: Colors.black.withValues(alpha: 0.5),
                      blurRadius: 4,
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
        SizedBox(height: 14.h),
        // 推荐码输入框 - 使用 AnimatedSize 平滑过渡
        AnimatedSize(
          duration: const Duration(milliseconds: 200),
          curve: Curves.easeInOut,
          child: _hasReferrer
              ? Container(
                  padding: EdgeInsets.symmetric(vertical: 8.h, horizontal: 4.w),
                  decoration: BoxDecoration(
                    border: Border(
                      bottom: BorderSide(
                        width: 1,
                        color: Colors.white.withValues(alpha: 0.5),
                      ),
                    ),
                  ),
                  child: Row(
                    children: [
                      Expanded(
                        child: GestureDetector(
                          onTap: _openQrScanner,
                          child: AbsorbPointer(
                            child: TextField(
                              controller: _referralCodeController,
                              readOnly: true,
                              decoration: InputDecoration(
                                hintText: '点击扫描推荐码',
                                hintStyle: TextStyle(
                                  fontSize: 16.sp,
                                  color: Colors.black.withValues(alpha: 0.4),
                                ),
                                border: InputBorder.none,
                                isDense: true,
                                contentPadding: EdgeInsets.zero,
                              ),
                              style: TextStyle(
                                fontSize: 16.sp,
                                color: Colors.black,
                              ),
                            ),
                          ),
                        ),
                      ),
                      // 扫码按钮
                      GestureDetector(
                        onTap: _openQrScanner,
                        child: Padding(
                          padding: EdgeInsets.only(left: 8.w),
                          child: Icon(
                            Icons.camera_alt_outlined,
                            size: 20.sp,
                            color: Colors.white.withValues(alpha: 0.8),
                          ),
                        ),
                      ),
                    ],
                  ),
                )
              : const SizedBox.shrink(),
        ),
        SizedBox(height: 24.h),
        // 没有推荐人选项
        GestureDetector(
          onTap: () {
            setState(() {
              _hasReferrer = false;
            });
          },
          child: Row(
            children: [
              _buildRadio(!_hasReferrer),
              SizedBox(width: 12.w),
              Text(
                '我没有推荐人',
                style: TextStyle(
                  fontSize: 16.sp,
                  height: 1.5,
                  color: Colors.white,
                  shadows: [
                    Shadow(
                      color: Colors.black.withValues(alpha: 0.5),
                      blurRadius: 4,
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
        SizedBox(height: 32.h),
        // 分隔线
        Row(
          children: [
            Expanded(
              child: Container(
                height: 1,
                color: Colors.white.withValues(alpha: 0.3),
              ),
            ),
            Padding(
              padding: EdgeInsets.symmetric(horizontal: 16.w),
              child: Text(
                '或',
                style: TextStyle(
                  fontSize: 14.sp,
                  color: Colors.white.withValues(alpha: 0.7),
                ),
              ),
            ),
            Expanded(
              child: Container(
                height: 1,
                color: Colors.white.withValues(alpha: 0.3),
              ),
            ),
          ],
        ),
        SizedBox(height: 24.h),
        // 导入助记词入口
        GestureDetector(
          onTap: _importMnemonic,
          child: Container(
            width: double.infinity,
            padding: EdgeInsets.symmetric(vertical: 14.h),
            decoration: BoxDecoration(
              color: Colors.white.withValues(alpha: 0.15),
              borderRadius: BorderRadius.circular(12.r),
              border: Border.all(
                color: Colors.white.withValues(alpha: 0.3),
                width: 1,
              ),
            ),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Icon(
                  Icons.restore,
                  size: 20.sp,
                  color: Colors.white,
                ),
                SizedBox(width: 8.w),
                Text(
                  '已有账号？导入助记词恢复',
                  style: TextStyle(
                    fontSize: 15.sp,
                    fontWeight: FontWeight.w500,
                    color: Colors.white,
                  ),
                ),
              ],
            ),
          ),
        ),
      ],
    );
  }

  /// 构建单选按钮 (白色系，适配深色背景)
  Widget _buildRadio(bool isSelected) {
    return Container(
      width: 20.w,
      height: 20.w,
      decoration: BoxDecoration(
        shape: BoxShape.circle,
        border: Border.all(
          width: isSelected ? 6.w : 2.w,
          color: isSelected
              ? Colors.white
              : Colors.white.withValues(alpha: 0.5),
        ),
      ),
    );
  }
}

/// 二维码扫描页面
class _QrScannerPage extends StatefulWidget {
  const _QrScannerPage();

  @override
  State<_QrScannerPage> createState() => _QrScannerPageState();
}

class _QrScannerPageState extends State<_QrScannerPage> {
  MobileScannerController? _controller;
  bool _hasScanned = false;
  bool _torchOn = false;
  bool _isProcessingImage = false;

  @override
  void initState() {
    super.initState();
    _controller = MobileScannerController(
      detectionSpeed: DetectionSpeed.normal,
      facing: CameraFacing.back,
    );
  }

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

  void _onDetect(BarcodeCapture capture) {
    if (_hasScanned) return;

    final List<Barcode> barcodes = capture.barcodes;
    for (final barcode in barcodes) {
      if (barcode.rawValue != null && barcode.rawValue!.isNotEmpty) {
        _hasScanned = true;
        Navigator.of(context).pop(barcode.rawValue);
        return;
      }
    }
  }

  Future<void> _toggleTorch() async {
    await _controller?.toggleTorch();
    setState(() {
      _torchOn = !_torchOn;
    });
  }

  /// 从相册选择图片并扫描二维码
  Future<void> _pickImageAndScan() async {
    if (_isProcessingImage || _hasScanned) return;

    setState(() {
      _isProcessingImage = true;
    });

    try {
      final ImagePicker picker = ImagePicker();
      final XFile? image = await picker.pickImage(source: ImageSource.gallery);

      if (image == null) {
        setState(() {
          _isProcessingImage = false;
        });
        return;
      }

      // 使用 MobileScannerController 分析图片
      final BarcodeCapture? result = await _controller?.analyzeImage(image.path);

      if (result != null && result.barcodes.isNotEmpty) {
        for (final barcode in result.barcodes) {
          if (barcode.rawValue != null && barcode.rawValue!.isNotEmpty) {
            _hasScanned = true;
            if (mounted) {
              Navigator.of(context).pop(barcode.rawValue);
            }
            return;
          }
        }
      }

      // 未识别到二维码
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(
              '未能识别图片中的二维码，请重新选择',
              style: TextStyle(fontSize: 14.sp),
            ),
            backgroundColor: const Color(0xFF6F6354),
            behavior: SnackBarBehavior.floating,
            margin: EdgeInsets.all(16.w),
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(8.r),
            ),
          ),
        );
      }
    } catch (e) {
      debugPrint('扫描图片失败: $e');
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(
              '图片扫描失败，请重试',
              style: TextStyle(fontSize: 14.sp),
            ),
            backgroundColor: Colors.red,
            behavior: SnackBarBehavior.floating,
            margin: EdgeInsets.all(16.w),
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(8.r),
            ),
          ),
        );
      }
    } finally {
      if (mounted) {
        setState(() {
          _isProcessingImage = false;
        });
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      appBar: AppBar(
        backgroundColor: Colors.black,
        leading: IconButton(
          icon: const Icon(Icons.arrow_back, color: Colors.white),
          onPressed: () => Navigator.of(context).pop(),
        ),
        title: Text(
          '扫描推荐码',
          style: TextStyle(
            fontSize: 18.sp,
            color: Colors.white,
          ),
        ),
        centerTitle: true,
        actions: [
          IconButton(
            icon: Icon(
              _torchOn ? Icons.flash_on : Icons.flash_off,
              color: Colors.white,
            ),
            onPressed: _toggleTorch,
          ),
        ],
      ),
      body: Stack(
        children: [
          // 扫描区域
          MobileScanner(
            controller: _controller,
            onDetect: _onDetect,
          ),
          // 扫描框遮罩
          _buildScanOverlay(),
          // 底部区域：提示文字和相册按钮
          Positioned(
            bottom: 60.h,
            left: 0,
            right: 0,
            child: Column(
              children: [
                Text(
                  '将二维码放入框内，即可自动扫描',
                  style: TextStyle(
                    fontSize: 14.sp,
                    color: Colors.white70,
                  ),
                  textAlign: TextAlign.center,
                ),
                SizedBox(height: 32.h),
                // 相册按钮
                GestureDetector(
                  onTap: _isProcessingImage ? null : _pickImageAndScan,
                  child: Container(
                    padding: EdgeInsets.symmetric(horizontal: 24.w, vertical: 12.h),
                    decoration: BoxDecoration(
                      color: Colors.white.withValues(alpha: 0.15),
                      borderRadius: BorderRadius.circular(24.r),
                      border: Border.all(
                        color: Colors.white.withValues(alpha: 0.3),
                        width: 1,
                      ),
                    ),
                    child: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        if (_isProcessingImage)
                          SizedBox(
                            width: 18.sp,
                            height: 18.sp,
                            child: const CircularProgressIndicator(
                              strokeWidth: 2,
                              valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
                            ),
                          )
                        else
                          Icon(
                            Icons.photo_library_outlined,
                            size: 18.sp,
                            color: Colors.white,
                          ),
                        SizedBox(width: 8.w),
                        Text(
                          _isProcessingImage ? '识别中...' : '从相册选择',
                          style: TextStyle(
                            fontSize: 14.sp,
                            color: Colors.white,
                          ),
                        ),
                      ],
                    ),
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  /// 构建扫描框遮罩
  Widget _buildScanOverlay() {
    return LayoutBuilder(
      builder: (context, constraints) {
        final scanAreaSize = 250.w;
        final left = (constraints.maxWidth - scanAreaSize) / 2;
        final top = (constraints.maxHeight - scanAreaSize) / 2 - 50.h;

        return Stack(
          children: [
            // 半透明背景
            ColorFiltered(
              colorFilter: ColorFilter.mode(
                Colors.black.withValues(alpha: 0.6),
                BlendMode.srcOut,
              ),
              child: Stack(
                children: [
                  Container(
                    decoration: const BoxDecoration(
                      color: Colors.black,
                      backgroundBlendMode: BlendMode.dstOut,
                    ),
                  ),
                  Positioned(
                    left: left,
                    top: top,
                    child: Container(
                      width: scanAreaSize,
                      height: scanAreaSize,
                      decoration: BoxDecoration(
                        color: Colors.white,
                        borderRadius: BorderRadius.circular(12.r),
                      ),
                    ),
                  ),
                ],
              ),
            ),
            // 扫描框边角
            Positioned(
              left: left,
              top: top,
              child: _buildCorner(true, true),
            ),
            Positioned(
              right: left,
              top: top,
              child: _buildCorner(false, true),
            ),
            Positioned(
              left: left,
              bottom: constraints.maxHeight - top - scanAreaSize,
              child: _buildCorner(true, false),
            ),
            Positioned(
              right: left,
              bottom: constraints.maxHeight - top - scanAreaSize,
              child: _buildCorner(false, false),
            ),
          ],
        );
      },
    );
  }

  /// 构建边角装饰
  Widget _buildCorner(bool isLeft, bool isTop) {
    return SizedBox(
      width: 24.w,
      height: 24.w,
      child: CustomPaint(
        painter: _CornerPainter(
          isLeft: isLeft,
          isTop: isTop,
          color: const Color(0xFFD4A84B),
          strokeWidth: 3.w,
        ),
      ),
    );
  }
}

/// 边角绘制器
class _CornerPainter extends CustomPainter {
  final bool isLeft;
  final bool isTop;
  final Color color;
  final double strokeWidth;

  _CornerPainter({
    required this.isLeft,
    required this.isTop,
    required this.color,
    required this.strokeWidth,
  });

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = color
      ..strokeWidth = strokeWidth
      ..style = PaintingStyle.stroke
      ..strokeCap = StrokeCap.round;

    final path = Path();

    if (isLeft && isTop) {
      path.moveTo(0, size.height);
      path.lineTo(0, 0);
      path.lineTo(size.width, 0);
    } else if (!isLeft && isTop) {
      path.moveTo(0, 0);
      path.lineTo(size.width, 0);
      path.lineTo(size.width, size.height);
    } else if (isLeft && !isTop) {
      path.moveTo(0, 0);
      path.lineTo(0, size.height);
      path.lineTo(size.width, size.height);
    } else {
      path.moveTo(0, size.height);
      path.lineTo(size.width, size.height);
      path.lineTo(size.width, 0);
    }

    canvas.drawPath(path, paint);
  }

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