Secret Chat

using System;
using System.Linq;


class Program
{
    static void Main()
    {
        string message = Console.ReadLine();
        string input;
        while ((input = Console.ReadLine()) != "Reveal")
        {
            string[] tokens = input.Split(":|:");
            if (tokens[0] == "InsertSpace")
            {
                message = message.Insert(int.Parse(tokens[1]), " ");
            }
            else if (tokens[0] == "Reverse")
            {
                string substring = tokens[1];
                if (!message.Contains(substring))
                {
                    Console.WriteLine("error");
                    continue;
                }
                message = message.Remove(message.IndexOf(substring), substring.Length);
                string reversedSubstring = string.Join("", substring.ToCharArray().Reverse());
                message += reversedSubstring;
            }
            else if (tokens[0] == "ChangeAll")
            {
                message = message.Replace(tokens[1], tokens[2]);
            }
            Console.WriteLine(message);
        }

        Console.WriteLine($"You have a new text message: {message}");
    }
}