BizTalkPlatformManagementTool/src/BizTalkPlatformManagementTool/Services/OperationLogger.cs

using System;
using System.Globalization;
using System.IO;
using System.Threading;

namespace BizTalkPlatformManagementTool.Services
{
    public enum LogLevel
    {
        Info,
        Warning,
        Error,
        Success
    }

    public sealed class LogEntry
    {
        public DateTime Timestamp { get; set; }
        public LogLevel Level { get; set; }
        public string Message { get; set; }
    }

    public sealed class OperationLogger
    {
        private const string LogFilePrefix = "BizTalkPlatformManagementTool-";
        private const string LogFileExtension = ".log";
        private const int RetentionDays = 5;
        private static readonly object FileLock = new object();
        private static int _cleanupDone;

        private readonly Action<LogEntry> _sink;
        private readonly string _logDirectory;

        public OperationLogger(Action<LogEntry> sink)
        {
            _sink = sink;
            _logDirectory = AppDomain.CurrentDomain.BaseDirectory;
            CleanupOldLogs();
        }

        public string LogFilePath
        {
            get
            {
                return Path.Combine(_logDirectory, LogFilePrefix + DateTime.Now.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture) + LogFileExtension);
            }
        }

        public void Info(string message)
        {
            Write(LogLevel.Info, message);
        }

        public void Warning(string message)
        {
            Write(LogLevel.Warning, message);
        }

        public void Error(string message)
        {
            Write(LogLevel.Error, message);
        }

        public void Success(string message)
        {
            Write(LogLevel.Success, message);
        }

        private void Write(LogLevel level, string message)
        {
            var entry = new LogEntry
            {
                Timestamp = DateTime.Now,
                Level = level,
                Message = message
            };

            WriteToFile(entry);

            if (_sink == null)
            {
                return;
            }

            _sink(entry);
        }

        private void WriteToFile(LogEntry entry)
        {
            try
            {
                var line = string.Format(
                    CultureInfo.InvariantCulture,
                    "[{0:yyyy-MM-dd HH:mm:ss}][{1}] {2}{3}",
                    entry.Timestamp,
                    entry.Level.ToString().ToUpperInvariant(),
                    entry.Message,
                    Environment.NewLine);

                lock (FileLock)
                {
                    File.AppendAllText(LogFilePath, line);
                }
            }
            catch
            {
                // Logging must never interrupt BizTalk operations.
            }
        }

        private void CleanupOldLogs()
        {
            if (Interlocked.Exchange(ref _cleanupDone, 1) == 1)
            {
                return;
            }

            try
            {
                var cutoff = DateTime.Now.Date.AddDays(-(RetentionDays - 1));
                foreach (var file in Directory.GetFiles(_logDirectory, LogFilePrefix + "*" + LogFileExtension))
                {
                    var lastWrite = File.GetLastWriteTime(file);
                    if (lastWrite.Date < cutoff)
                    {
                        File.Delete(file);
                    }
                }
            }
            catch
            {
                // Log retention cleanup is best-effort.
            }
        }
    }
}