marking_gui/marking_gui/Services/LoggerService.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;

namespace marking_gui.Services
{
    public static class LoggerService
    {
        private static readonly string LogDirectory = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Logs");
        private static readonly string DiagnosticDirectory = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "debug");
        private static readonly object LockObj = new object();
        private static readonly Queue<string> RecentLogs = new Queue<string>();
        private const int RecentLogLimit = 100;

        static LoggerService()
        {
            try
            {
                if (!Directory.Exists(LogDirectory))
                {
                    Directory.CreateDirectory(LogDirectory);
                }

                // 오래된 로그 정리 태스크 백그라운드 구동 (애플리케이션 시작 차단 방지)
                System.Threading.Tasks.Task.Run(() => CleanUpOldLogs(30));
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine("Log directory creation failed: " + ex.Message);
            }
        }

        private static void CleanUpOldLogs(int retentionDays)
        {
            try
            {
                var dirInfo = new DirectoryInfo(LogDirectory);
                if (!dirInfo.Exists) return;

                DateTime threshold = DateTime.Now.AddDays(-retentionDays);
                foreach (var file in dirInfo.GetFiles("*.log"))
                {
                    try
                    {
                        if (file.LastWriteTime < threshold)
                        {
                            file.Delete();
                            System.Diagnostics.Debug.WriteLine($"[SRE Logger] 만료된 로그 파일 삭제 완료: {file.Name}");
                        }
                    }
                    catch (Exception fileEx)
                    {
                        System.Diagnostics.Debug.WriteLine($"[SRE Logger] 로그 파일 삭제 중 예외 (파일명: {file.Name}): {fileEx.Message}");
                    }
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine("[SRE Logger] 만료 로그 정리 중 예외 발생: " + ex.Message);
            }
        }

        public static void Info(string message)
        {
            WriteLog("INFO", message);
        }

        public static void Warn(string message)
        {
            WriteLog("WARN", message);
        }

        public static void Error(string message, Exception ex = null, string context = null)
        {
            string detail = message;
            if (ex != null)
            {
                // ToString preserves exception types, inner exceptions and their stack traces.
                detail += Environment.NewLine + ex;
            }
            WriteLog("ERROR", detail, context);
        }

        private static void WriteLog(string level, string message, string context = null)
        {
            lock (LockObj)
            {
                DateTime now = DateTime.Now;
                string logLine = string.Format("[{0}] [{1}] {2}", now.ToString("yyyy-MM-dd HH:mm:ss.fff zzz"), level, message) + Environment.NewLine;
                RecentLogs.Enqueue(logLine);
                while (RecentLogs.Count > RecentLogLimit) RecentLogs.Dequeue();

                // Keep diagnostic and daily writes independent so either can survive a failure in the other.
                if (level == "ERROR")
                {
                    try
                    {
                        Directory.CreateDirectory(DiagnosticDirectory);
                        string diagnosticFile = Path.Combine(DiagnosticDirectory,
                            $"error_{now:yyyyMMdd_HHmmss_fff}_{Guid.NewGuid():N}.log");
                        var report = new StringBuilder();
                        report.AppendLine($"발생 시각: {now:yyyy-MM-dd HH:mm:ss.fff zzz}");
                        report.AppendLine($"프로그램 버전: {typeof(LoggerService).Assembly.GetName().Version}");
                        report.AppendLine($"실행 경로: {AppDomain.CurrentDomain.BaseDirectory}");
                        report.AppendLine($"실행 환경: {RuntimeInformation.FrameworkDescription}, {RuntimeInformation.OSDescription}, {RuntimeInformation.ProcessArchitecture}");
                        report.AppendLine($"프로세스 ID: {Environment.ProcessId}, 스레드 ID: {Environment.CurrentManagedThreadId}");
                        report.AppendLine();
                        report.AppendLine("[오류 상세]");
                        report.AppendLine(message);
                        if (!string.IsNullOrWhiteSpace(context))
                        {
                            report.AppendLine();
                            report.AppendLine("[진단 정보]");
                            report.AppendLine(context);
                        }
                        report.AppendLine();
                        report.AppendLine($"[직전 로그 - 최대 {RecentLogLimit}건]");
                        foreach (string recent in RecentLogs) report.Append(recent);
                        File.WriteAllText(diagnosticFile, report.ToString(), Encoding.UTF8);
                        logLine += "[진단 파일] " + diagnosticFile + Environment.NewLine;
                    }
                    catch (Exception ex)
                    {
                        logLine += "[진단 파일 저장 실패] " + ex.Message + Environment.NewLine;
                        System.Diagnostics.Debug.WriteLine("Writing diagnostic failed: " + ex.Message);
                    }
                }

                try
                {
                    Directory.CreateDirectory(LogDirectory);
                    string logFile = Path.Combine(LogDirectory, now.ToString("yyyy-MM-dd") + ".log");
                    if (!string.IsNullOrWhiteSpace(context))
                        logLine += "[진단 정보] " + context + Environment.NewLine;
                    File.AppendAllText(logFile, logLine);
                }
                catch (Exception ex)
                {
                    System.Diagnostics.Debug.WriteLine("Writing log failed: " + ex.Message);
                }
            }
        }
    }
}