Innovenergy_trunk/csharp/App/SaliMax/src/Logfile.cs

using InnovEnergy.Lib.Utils;
using Microsoft.Extensions.Logging;

namespace InnovEnergy.App.SaliMax;

public class CustomLogger : ILogger
{
    private readonly String _logFilePath;
    //private readonly Int64  _maxFileSizeBytes;
    private readonly Int32  _maxLogFileCount;
    private          Int64  _currentFileSizeBytes;

    public CustomLogger(String logFilePath, Int32 maxLogFileCount)
    {
        _logFilePath          = logFilePath;
        _maxLogFileCount      = maxLogFileCount;
        _currentFileSizeBytes = File.Exists(logFilePath) ? new FileInfo(logFilePath).Length : 0;
    }

    public IDisposable? BeginScope<TState>(TState state) where TState : notnull => throw new NotImplementedException();

    public Boolean IsEnabled(LogLevel logLevel) => true; // Enable logging for all levels

    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception, String> formatter)
    {
        var logMessage = formatter(state, exception!);
        
        // Check the log file count and delete the oldest file if necessary
        var logFileDir      = Path.GetDirectoryName(_logFilePath)!;
        var logFileExt      = Path.GetExtension(_logFilePath);
        var logFileBaseName = Path.GetFileNameWithoutExtension(_logFilePath);
        
        var logFiles = Directory
            .GetFiles(logFileDir, $"{logFileBaseName}_*{logFileExt}")
            .OrderBy(file => file)
            .ToList();

        if (logFiles.Count >= _maxLogFileCount)
        {
            File.Delete(logFiles.First());
        }

        var roundedUnixTimestamp = DateTime.Now.ToUnixTime() % 2 == 0 ? DateTime.Now.ToUnixTime() : DateTime.Now.ToUnixTime() + 1;
        var timestamp = "Timestamp;" + roundedUnixTimestamp + Environment.NewLine;
        
        var logFileBackupPath = Path.Combine(logFileDir, $"{logFileBaseName}_{DateTime.Now.ToUnixTime()}{logFileExt}");
        File.AppendAllText(logFileBackupPath, timestamp + logMessage + Environment.NewLine);
    }
}