using System;
using System.IO;
using System.Net;
using System.Text.RegularExpressions;
using HtmlAgilityPack;

namespace mtg_rules_dler
{
    class Program
    {
        static void Main(string[] args)
        {

            HtmlWeb web = new HtmlWeb();

            var htmlDoc = web.Load("https://magic.wizards.com/en/game-info/gameplay/rules-and-formats/rules");

            var links = htmlDoc.DocumentNode.SelectNodes("//div[contains(@id,'comprehensive-rules')]//a");
            if (links == null || links.Count == 0)
            {
                Console.Error.WriteLine("can't find any links.");
                return;
            }

            var linkTarget = "";
            var found = false;
            foreach (var link in links)
            {
                linkTarget = link.Attributes["href"]?.Value;
                if (linkTarget?.EndsWith(".txt") == true)
                {
                    found = true;
                    break;
                }
            }
            if (!found)
            {
                Console.Error.WriteLine("couldn't find link to rules.txt");
                return;
            }

            var request = WebRequest.Create(linkTarget);
            var response = request.GetResponse();

            var responseAsText = "";
            using (var dataStream = new StreamReader(response.GetResponseStream()))
            {
                responseAsText = dataStream.ReadToEnd();
            }

            if (File.Exists("MagicCompRules.txt"))
            {
                if (File.ReadAllText("MagicCompRules.txt") == responseAsText)
                {
                    Console.WriteLine("no update.");
                    return;
                }
            }
            File.WriteAllText("MagicCompRules.txt", responseAsText);

            File.WriteAllText("MagicCompRules.NoNums.txt", new Regex("\\b\\d+(\\.\\d+)?([\\w]+)?\\b").Replace(responseAsText, "#"));
        }
    }
}