import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart' show kIsWeb;
import '../theme/app_theme.dart';
import '../database/app_usage_dao.dart';
import '../database/daily_stats_dao.dart';

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

  @override
  State<DataPrivacyScreen> createState() => _DataPrivacyScreenState();
}

class _DataPrivacyScreenState extends State<DataPrivacyScreen> {
  final AppUsageDao _appUsageDao = AppUsageDao();
  final DailyStatsDao _dailyStatsDao = DailyStatsDao();
  bool _isDeleting = false;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);

    return Scaffold(
      appBar: AppBar(
        title: const Text('数据与隐私'),
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            // 隐私说明
            Card(
              child: Padding(
                padding: const EdgeInsets.all(16),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Row(
                      children: [
                        Icon(Icons.security, color: AppTheme.primaryColor),
                        const SizedBox(width: 8),
                        Text(
                          '隐私保护',
                          style: theme.textTheme.titleMedium?.copyWith(
                            fontWeight: FontWeight.w600,
                          ),
                        ),
                      ],
                    ),
                    const SizedBox(height: 16),
                    _buildPrivacyItem(
                      theme,
                      Icons.storage,
                      '本地存储',
                      '所有数据仅存储在您的设备本地，不会上传到任何服务器。',
                    ),
                    _buildPrivacyItem(
                      theme,
                      Icons.lock,
                      '数据加密',
                      '敏感数据在存储时进行加密处理，确保数据安全。',
                    ),
                    _buildPrivacyItem(
                      theme,
                      Icons.visibility_off,
                      '隐私保护',
                      '我们不会收集您的个人信息，也不会追踪您的具体操作内容。',
                    ),
                    _buildPrivacyItem(
                      theme,
                      Icons.delete_forever,
                      '完全控制',
                      '您可以随时删除所有数据，完全掌控您的隐私。',
                    ),
                  ],
                ),
              ),
            ),
            const SizedBox(height: 16),

            // 数据管理
            Card(
              child: Padding(
                padding: const EdgeInsets.all(16),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      '数据管理',
                      style: theme.textTheme.titleMedium?.copyWith(
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                    const SizedBox(height: 16),
                    _buildDataAction(
                      context,
                      theme,
                      Icons.delete_outline,
                      '删除旧数据',
                      '删除 30 天前的数据',
                      Colors.orange,
                      () => _showDeleteOldDataDialog(context),
                    ),
                    const SizedBox(height: 12),
                    _buildDataAction(
                      context,
                      theme,
                      Icons.delete_forever,
                      '清空所有数据',
                      '删除所有使用记录和统计数据',
                      Colors.red,
                      () => _showDeleteAllDataDialog(context),
                    ),
                  ],
                ),
              ),
            ),
            const SizedBox(height: 16),

            // 数据使用说明
            Card(
              child: Padding(
                padding: const EdgeInsets.all(16),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      '数据使用说明',
                      style: theme.textTheme.titleMedium?.copyWith(
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                    const SizedBox(height: 12),
                    Text(
                      '• 应用使用数据仅用于统计和分析\n'
                      '• 数据不会离开您的设备\n'
                      '• 不会与第三方分享任何数据\n'
                      '• 不会用于广告或营销目的\n'
                      '• 您可以随时导出或删除数据',
                      style: theme.textTheme.bodyMedium,
                    ),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildPrivacyItem(ThemeData theme, IconData icon, String title, String description) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 16),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Icon(icon, color: AppTheme.primaryColor, size: 24),
          const SizedBox(width: 12),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  title,
                  style: theme.textTheme.bodyLarge?.copyWith(
                    fontWeight: FontWeight.w600,
                  ),
                ),
                const SizedBox(height: 4),
                Text(
                  description,
                  style: theme.textTheme.bodySmall?.copyWith(
                    color: theme.colorScheme.onSurface.withOpacity(0.6),
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildDataAction(
    BuildContext context,
    ThemeData theme,
    IconData icon,
    String title,
    String subtitle,
    Color color,
    VoidCallback onTap,
  ) {
    return InkWell(
      onTap: _isDeleting ? null : onTap,
      borderRadius: BorderRadius.circular(8),
      child: Container(
        padding: const EdgeInsets.all(12),
        decoration: BoxDecoration(
          border: Border.all(color: color.withOpacity(0.3)),
          borderRadius: BorderRadius.circular(8),
        ),
        child: Row(
          children: [
            Icon(icon, color: color),
            const SizedBox(width: 12),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    title,
                    style: theme.textTheme.bodyLarge?.copyWith(
                      fontWeight: FontWeight.w600,
                      color: color,
                    ),
                  ),
                  const SizedBox(height: 4),
                  Text(
                    subtitle,
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: theme.colorScheme.onSurface.withOpacity(0.6),
                    ),
                  ),
                ],
              ),
            ),
            if (_isDeleting)
              const SizedBox(
                width: 20,
                height: 20,
                child: CircularProgressIndicator(strokeWidth: 2),
              )
            else
              const Icon(Icons.chevron_right),
          ],
        ),
      ),
    );
  }

  void _showDeleteOldDataDialog(BuildContext context) {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('删除旧数据'),
        content: const Text('确定要删除 30 天前的所有数据吗？此操作不可恢复。'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(),
            child: const Text('取消'),
          ),
          ElevatedButton(
            onPressed: () async {
              Navigator.of(context).pop();
              await _deleteOldData(context);
            },
            style: ElevatedButton.styleFrom(
              backgroundColor: Colors.orange,
            ),
            child: const Text('删除'),
          ),
        ],
      ),
    );
  }

  void _showDeleteAllDataDialog(BuildContext context) {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('清空所有数据'),
        content: const Text(
          '确定要删除所有使用记录和统计数据吗？\n\n'
          '此操作将：\n'
          '• 删除所有应用使用记录\n'
          '• 删除所有统计数据\n'
          '• 删除所有分类设置\n'
          '• 删除所有目标设置\n\n'
          '此操作不可恢复！',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(),
            child: const Text('取消'),
          ),
          ElevatedButton(
            onPressed: () async {
              Navigator.of(context).pop();
              await _deleteAllData(context);
            },
            style: ElevatedButton.styleFrom(
              backgroundColor: Colors.red,
            ),
            child: const Text('确认删除'),
          ),
        ],
      ),
    );
  }

  Future<void> _deleteOldData(BuildContext context) async {
    if (kIsWeb) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('Web 平台不支持数据删除功能'),
          backgroundColor: AppTheme.warningColor,
        ),
      );
      return;
    }

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

    try {
      final thirtyDaysAgo = DateTime.now().subtract(const Duration(days: 30));
      
      await _appUsageDao.deleteBeforeDate(thirtyDaysAgo);
      await _dailyStatsDao.deleteBeforeDate(thirtyDaysAgo);

      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('已删除 30 天前的数据'),
            backgroundColor: AppTheme.successColor,
          ),
        );
      }
    } catch (e) {
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('删除失败: $e'),
            backgroundColor: AppTheme.errorColor,
          ),
        );
      }
    } finally {
      if (mounted) {
        setState(() {
          _isDeleting = false;
        });
      }
    }
  }

  Future<void> _deleteAllData(BuildContext context) async {
    if (kIsWeb) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('Web 平台不支持数据删除功能'),
          backgroundColor: AppTheme.warningColor,
        ),
      );
      return;
    }

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

    try {
      // 删除所有应用使用记录
      final allUsages = await _appUsageDao.getAppUsages(
        startTime: DateTime(2000),
        endTime: DateTime.now(),
      );
      for (final usage in allUsages) {
        if (usage.id != null) {
          await _appUsageDao.deleteAppUsage(usage.id!);
        }
      }

      // 删除所有统计数据
      final allStats = await _dailyStatsDao.getStatsRange(
        startDate: DateTime(2000),
        endDate: DateTime.now(),
      );
      for (final stat in allStats) {
        if (stat.id != null) {
          await _dailyStatsDao.deleteDailyStats(stat.id!);
        }
      }

      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('已清空所有数据'),
            backgroundColor: AppTheme.successColor,
          ),
        );
      }
    } catch (e) {
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('删除失败: $e'),
            backgroundColor: AppTheme.errorColor,
          ),
        );
      }
    } finally {
      if (mounted) {
        setState(() {
          _isDeleting = false;
        });
      }
    }
  }
}