Reduce File Path

ReduceFilePath

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

namespace ReduceFilePath
{
    class ReduceFilePath
    {
        public const string CurrentFolderToken = ".";
        public const string ParentFolderToken = "..";
        public const char TokensDelimiter = '/';

        static void Main()
        {
            while (true)
            {
                Console.Write("Enter a path to reduce: ");
                string path = Console.ReadLine();
                string reducedPath = ReducePath(path);
                Console.Write("Reduced path: ");
                Console.WriteLine(reducedPath);
            }
        }

        public static string ReducePath(string path)
        {
            if (path == null)
            {
                throw new ArgumentNullException("path");
            }
            bool hasLastDash = (path[path.Length - 1] == '/');
            string[] pathTokens = path.Split(new char[] { TokensDelimiter }, StringSplitOptions.RemoveEmptyEntries);
            Stack<string> tokensStack = new Stack<string>();
            int rootOffset = 0; // the depth level relative to the root
            foreach (string token in pathTokens)
            {
                if (token == ParentFolderToken)
                {
                    // If we are in a root descendant - remove the last folder
                    if (rootOffset > 0)
                    {
                        tokensStack.Pop();
                    }
                    rootOffset--;
                }
                else if (token != CurrentFolderToken)
                {
                    tokensStack.Push(token);
                    rootOffset++;
                }
            }

            // Handles cases like "/../" where the last dash has meaning
            if (hasLastDash && rootOffset == -1)
            {
                rootOffset++;
            }
            // If the result directory is above the root
            if (rootOffset < 0)
            {
                throw new Exception("Invalid path. There is no folders above the root.");
            }

            return "/" + String.Join("/", tokensStack.Reverse());
        }
    }
}