using Microsoft.Extensions.Configuration;
using System;
using System.IO;
using System.Text;

/// <summary>
/// 文件日志写入封装类，自动按日期分文件、超大小自动切割
/// </summary>
public class FileLog
{
    private readonly IConfiguration _configuration;
    private readonly object _lockObj = new object(); // 独立锁，不依赖外部this

    public FileLog(IConfiguration configuration)
    {
        _configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
    }

    /// <summary>
    /// 写入日志内容到文件
    /// </summary>
    /// <param name="log">日志文本</param>
    public void WriteToFile(string log)
    {
        try
        {
            // 读取配置，转换最大文件字节数
            int maxMb = _configuration.GetValue<int>("Logging:MaxFileSizeMB");
            long maxFileSizeBytes = (long)maxMb * 1024 * 1024;

            string today = DateTime.Now.ToString("yyyyMMdd");
            string basePath = _configuration["Logging:LogFileDirectory"];
            Directory.CreateDirectory(basePath);

            string baseFileName = $"log-{today}";
            string ext = ".log";
            string finalPath = Path.Combine(basePath, $"{baseFileName}{ext}");
            int index = 1;

            // 文件超限则递增后缀切割
            while (File.Exists(finalPath) && new FileInfo(finalPath).Length >= maxFileSizeBytes)
            {
                finalPath = Path.Combine(basePath, $"{baseFileName}-{index}{ext}");
                index++;
            }

            // 线程安全写入
            lock (_lockObj)
            {
                File.AppendAllText(finalPath, log + Environment.NewLine, Encoding.UTF8);
            }
        }
        catch
        {
            // 原逻辑吞掉所有异常，如需日志可自行增加内部异常输出
        }
    }
}