using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Threading;

namespace IdleMafiaBot
{

    static class LinuxPages
    {
        public static void Watch(Bot bot, Settings s, string dir)
        {
            string file = Path.Combine(dir, "link-status.json");
            object gate = new object();
            string said = null;
            Action write = () =>
            {
                try
                {
                    var stats = bot.Stats;
                    string json = "{\"stats\": " + Q(Tag(s.StatsLink)) + ", \"statsOn\": " + B(stats.On) + ", \"statsTrouble\": " + Q(stats.Trouble)
                                  + ", \"statsStatus\": " + Q(stats.On ? stats.Status : null) + ", \"notOurs\": " + B(stats.NotOurs)
                                  + ", \"remoteOn\": " + B(bot.Remote.On) + ", \"discord\": " + Q(Tag(s.DiscordLink))
                                  + ", \"discordTrouble\": " + Q(bot.Discord.Trouble) + "}\n";
                    lock (gate)
                    {
                        if (json == said) return;

                        string tmp = file + ".tmp";
                        File.WriteAllText(tmp, json);
                        if (File.Exists(file)) File.Replace(tmp, file, null);
                        else File.Move(tmp, file);
                        said = json;
                    }
                }
                catch (Exception) { }
            };
            bot.Stats.Changed += write;
            bot.Discord.Changed += write;
            new Thread(() => { while (true) { write(); Thread.Sleep(15000); } }) { IsBackground = true, Name = "link status" }.Start();
        }

        internal static string Tag(string link)
        {
            link = (link ?? "").Trim();
            if (link.Length == 0) return "";
            using (var sha = SHA256.Create())
            {
                var h = sha.ComputeHash(Encoding.UTF8.GetBytes(link));
                var sb = new StringBuilder();
                for (int i = 0; i < 8; i++) sb.Append(h[i].ToString("x2"));
                return sb.ToString();
            }
        }

        static string B(bool b) { return b ? "true" : "false"; }

        static string Q(string t)
        {
            if (t == null) return "null";
            var sb = new StringBuilder("\"");
            foreach (char c in t)
            {
                if (c == '"' || c == '\\') sb.Append('\\').Append(c);
                else if (c < ' ') sb.Append(' ');
                else sb.Append(c);
            }
            return sb.Append('"').ToString();
        }
    }
}