CSharp-FastLogHelper

namespace CSharpTest.Helpers;

/// <summary>
/// 快速输出日志帮助类
/// </summary>
public static class FastLogHelper
{
    static FastLogHelper()
    {
        logDirPath = System.IO.Path.Combine(System.AppDomain.CurrentDomain.BaseDirectory, "fast-error-log");

        CreateLogFolder();
        writeLogTask = Task.Run(async () =>
        {
            while (true)
            {
                if (IsLogQueueEmpty == false)
                {
                    // 如果日志数量大于100，则以100条日志为一个批次写入
                    if (logQueue.Count > 100)
                    {
                        Dictionary<string, List<string>> templateDict = new();
                        for (int i = 0; i < 100; i++)
                        {
                            var item = logQueue.Dequeue();
                            if (templateDict.ContainsKey(item.prefix) == false)
                            {
                                templateDict[item.prefix] = new List<string>();
                            }
                            var time = System.DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.FFF");
                            var template = $"[START][{time}][{item.content}][END]";
                            templateDict[item.prefix].Add(template);
                        }

                        foreach (var key in templateDict.Keys)
                        {
                            using var writer = GetLogFileWriter(key);
                            var content = string.Join(Environment.NewLine, templateDict[key]);
                            await writer.WriteLineAsync(content);
                            await writer.FlushAsync();
                            await writer.DisposeAsync();
                        }
                    }
                    else
                    {
                        // 否则就一条一条的写
                        var item = logQueue.Dequeue();
                        using var writer = GetLogFileWriter(item.prefix);
                        var time = System.DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.FFF");
                        var template = $"[START][{time}][{item.content}][END]";
                        await writer.WriteLineAsync(template);
                        await writer.FlushAsync();
                        await writer.DisposeAsync();
                    }
                }
                else
                {
                    await Task.Delay(50);
                }
            }
        });
    }

    /// <summary>
    /// 日志存储文件夹路径
    /// </summary>
    private static string logDirPath;

    /// <summary>
    /// 日志写入锁
    /// </summary>
    private static object writeLogLock = new();

    /// <summary>
    /// 日志队列
    /// </summary>
    private static Queue<(string content, string prefix)> logQueue = new(10000);

    /// <summary>
    /// 日志写入任务
    /// </summary>
    private static Task writeLogTask;

    /// <summary>
    /// 创建日志存储文件夹，当前程序目录下的 fast-error-log 文件夹
    /// </summary>
    private static void CreateLogFolder()
    {
        if (System.IO.Directory.Exists(logDirPath) == false)
        {
            System.IO.Directory.CreateDirectory(logDirPath);
        }
    }

    /// <summary>
    /// 是否存在 off.log 文件，如果存在，则不写日志
    /// </summary>
    /// <returns></returns>
    private static bool IsExistOffFile()
    {
        var offFilePath = Path.Combine(logDirPath, "off.log");
        return System.IO.File.Exists(offFilePath);
    }

    /// <summary>
    /// 创建日志文件，默认前缀fast,格式示例：fast-2012-12-12.log，如果日志文件大小大于1m,则文件会被重命名于fast-2012-12-12-X.log,然后写入新的数据
    /// </summary>
    /// <param name="prefix">日志文件前缀</param>
    /// <returns></returns>
    private static StreamWriter GetLogFileWriter(string prefix = "fast")
    {
        var fileNameWithoutExtension = $"{prefix}-{DateTime.Now.ToString("yyyy-MM-dd")}";
        var fileName = $"{fileNameWithoutExtension}.log";
        var logFilePath = Path.Combine(logDirPath, fileName);
        var file = new FileInfo(logFilePath);
        if (file.Exists == true)
        {
            // 大于 1M，创建新的文件
            if (file.Length > 1024 * 1024)
            {
                var files = Directory.GetFiles(logDirPath, $"{fileNameWithoutExtension}-*.log", SearchOption.TopDirectoryOnly);
                var maxIndex = 0;
                foreach (var f in files)
                {
                    var indexStr = Path.GetFileNameWithoutExtension(f).Substring(fileNameWithoutExtension.Length + 1);
                    var index = int.Parse(indexStr);
                    if (index > maxIndex)
                    {
                        maxIndex = index;
                    }
                }
                maxIndex += 1;
                string destFilename = Path.Combine(logDirPath, $"{fileNameWithoutExtension}-{maxIndex}.log");
                file.MoveTo(destFilename);
                file = new FileInfo(logFilePath);
            }
        }

        return file.AppendText();
    }

    /// <summary>
    /// 日志队列是否写入完毕
    /// </summary>
    /// <returns></returns>
    public static bool IsLogQueueEmpty => logQueue.Count == 0;

    /// <summary>
    /// 写日志
    /// </summary>
    /// <param name="content">日志内容</param>
    /// <param name="prefix">日志文件前缀</param>
    public static void WriteLog(string content, string prefix = "fast")
    {
        lock (writeLogLock)
        {
            if (IsExistOffFile())
            {
                return;
            }

            logQueue.Enqueue((content, prefix));
        }
    }
}