abp/framework/src/Volo.Abp.VirtualFileSystem/Volo/Abp/VirtualFileSystem/VirtualFilePathHelper.cs

using System;
using System.Collections.Generic;
using System.Linq;

namespace Volo.Abp.VirtualFileSystem
{
    internal static class VirtualFilePathHelper
    {
        //TODO: Optimize this class!

        public static string NormalizePath(string fullPath)
        {
            var fileName = fullPath;
            var extension = "";

            if (fileName.Contains("."))
            {
                extension = fullPath.Substring(fileName.LastIndexOf(".", StringComparison.Ordinal));
                if (extension.Contains("/"))
                {
                    //That means the file does not have extension, but a directory has "." char. So, clear extension.
                    extension = "";
                }
                else
                {
                    fileName = fullPath.Substring(0, fullPath.Length - extension.Length);
                }
            }

            return NormalizeChars(fileName) + extension;
        }
        
        private static string NormalizeChars(string fileName)
        {
            var folderParts = fileName.Replace(".", "/").Split("/");

            if (folderParts.Length == 1)
            {
                return folderParts[0];
            }

            return folderParts.Take(folderParts.Length - 1).Select(s => s.Replace("-", "_")).JoinAsString("/") + "/" + folderParts.Last();
        }
    }
}