using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace SmartScanner
{
    class ImageCleanupService
    {
        private readonly string _imageDirectory;
        private readonly int _retentionDays;
        private Timer _cleanupTimer;
        private bool _isRunning;

        public ImageCleanupService(string imageDirectory, int retentionDays)
        {
            _imageDirectory = imageDirectory;
            _retentionDays = retentionDays;
        }

        public void Start()
        {
            if (_isRunning) return;

            // 立即执行一次清理
            Task.Run(() => CleanupOldImages());

            // 设置每天凌晨2点执行清理
            var now = DateTime.Now;
            var nextRunTime = new DateTime(now.Year, now.Month, now.Day, 2, 0, 0).AddDays(1);
            var dueTime = nextRunTime - now;

            _cleanupTimer = new Timer(_ => CleanupOldImages(), null, dueTime, TimeSpan.FromDays(1));
            _isRunning = true;
        }

        public void Stop()
        {
            _cleanupTimer?.Dispose();
            _isRunning = false;
        }

        private void CleanupOldImages()
        {
            try
            {
                if (!Directory.Exists(_imageDirectory)) return;

                var cutoffDate = DateTime.Now.AddDays(-_retentionDays);
                var searchOption = SearchOption.AllDirectories;

                foreach (var file in Directory.EnumerateFiles(_imageDirectory, "*.*", searchOption))
                {
                    try
                    {
                        var fileInfo = new FileInfo(file);
                        if (fileInfo.LastWriteTime < cutoffDate)
                        {
                            File.Delete(file);
                            // 可选：记录删除日志
                            LogDeletion(file);
                        }
                    }
                    catch (Exception ex)
                    {
                        // 记录错误但继续处理其他文件
                        LogError($"删除文件失败: {file}", ex);
                    }
                }
            }
            catch (Exception ex)
            {
                LogError("清理旧图像时发生错误", ex);
            }
        }

        private void LogDeletion(string filePath)
        {
            // 实现日志记录，可以写入文件或数据库
            string logMessage = $"{DateTime.Now}: 已删除过期图像 - {filePath}";
            System.Diagnostics.Debug.WriteLine(logMessage);
        }

        private void LogError(string message, Exception ex)
        {
            // 实现错误日志记录
            string errorMessage = $"{DateTime.Now}: {message} - {ex.Message}";
            System.Diagnostics.Debug.WriteLine(errorMessage);
        }
    }
}