using System.Text;

namespace Gatedge.ScanCode.Common
{
    /// <summary>
    /// 文件日志帮助类
    /// </summary>
    public class FileLogger : ILogger
    {
        private readonly string _categoryName;
        private readonly string _filePath;
        private readonly long _maxFileSize; // 最大文件大小（字节）
        private readonly int _maxRetainedFiles; // 最大保留文件数

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="categoryName"></param>
        /// <param name="filePath"></param>
        /// <param name="maxFileSize"></param>
        /// <param name="maxRetainedFiles"></param>
        public FileLogger(string categoryName, string filePath, long maxFileSize = 10 * 1024 * 1024, int maxRetainedFiles = 5)
        {
            _categoryName = categoryName;
            _filePath = filePath;
            _maxFileSize = maxFileSize;
            _maxRetainedFiles = maxRetainedFiles;
        }

        /// <summary>
        /// 开始
        /// </summary>
        /// <typeparam name="TState"></typeparam>
        /// <param name="state"></param>
        /// <returns></returns>
        public IDisposable BeginScope<TState>(TState state) => null;

        /// <summary>
        /// 检测日志等级是否启用
        /// </summary>
        /// <param name="logLevel"></param>
        /// <returns></returns>
        public bool IsEnabled(LogLevel logLevel) => true;

        /// <summary>
        /// 写入日志
        /// </summary>
        /// <typeparam name="TState"></typeparam>
        /// <param name="logLevel"></param>
        /// <param name="eventId"></param>
        /// <param name="state"></param>
        /// <param name="exception"></param>
        /// <param name="formatter"></param>
        public void Log<TState>(
            LogLevel logLevel,
            EventId eventId,
            TState state,
            Exception exception,
            Func<TState, Exception, string> formatter)
        {
            // 过滤日志级别（可选）
            if (!IsEnabled(logLevel)) return;

            // 格式化日志消息
            var message = $"{DateTime.Now:yyyy-MM-dd HH:mm:ss} [{logLevel}] {_categoryName}: {formatter(state, exception)}{Environment.NewLine}";

            // 确保目录存在
            var directory = Path.GetDirectoryName(_filePath);
            if (!Directory.Exists(directory))
            {
                Directory.CreateDirectory(directory);
            }

            // 检查文件大小并滚动
            RollFileIfNeeded();

            // 写入日志
            File.AppendAllText(_filePath, message, Encoding.UTF8);
        }

        /// <summary>
        /// 文件滚动刷新
        /// </summary>
        private void RollFileIfNeeded()
        {
            try
            {
                var fileInfo = new FileInfo(_filePath);
                if (fileInfo.Exists && fileInfo.Length >= _maxFileSize)
                {
                    // 滚动文件命名：logs/app_20231005_001.log
                    var timestamp = DateTime.Now.ToString("yyyyMMdd");
                    var basePath = Path.Combine(
                        Path.GetDirectoryName(_filePath),
                        Path.GetFileNameWithoutExtension(_filePath)
                    );
                    var newFilePath = $"{basePath}_{timestamp}_{Guid.NewGuid():n}{Path.GetExtension(_filePath)}";
                    File.Move(_filePath, newFilePath);

                    // 清理旧文件
                    var directory = new DirectoryInfo(Path.GetDirectoryName(_filePath));
                    var files = directory.GetFiles($"{Path.GetFileNameWithoutExtension(_filePath)}_*")
                        .OrderByDescending(f => f.CreationTime)
                        .Skip(_maxRetainedFiles - 1)
                        .ToList();

                    foreach (var file in files)
                    {
                        file.Delete();
                    }
                }
            }
            catch
            {
                // 处理文件操作异常（如权限不足）
            }
        }
    }

    /// <summary>
    /// 日志写入帮助类
    /// </summary>
    public class FileLoggerProvider : ILoggerProvider
    {
        private readonly string _filePath;
        private readonly long _maxFileSize;
        private readonly int _maxRetainedFiles;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="filePath"></param>
        /// <param name="maxFileSize"></param>
        /// <param name="maxRetainedFiles"></param>
        public FileLoggerProvider(string filePath, long maxFileSize, int maxRetainedFiles)
        {
            _filePath = filePath;
            _maxFileSize = maxFileSize;
            _maxRetainedFiles = maxRetainedFiles;
        }
        /// <summary>
        /// 创建日志写入器
        /// </summary>
        /// <param name="categoryName"></param>
        /// <returns></returns>
        public ILogger CreateLogger(string categoryName)
        {
            return new FileLogger(categoryName, _filePath, _maxFileSize, _maxRetainedFiles);
        }
        /// <summary>
        /// 清理资源
        /// </summary>
        public void Dispose()
        {
            // 清理资源（如需要）
        }
    }
}