using System;
using System.Net;
using System.Net.Sockets;
using System.Threading.Tasks;
using System.IO;
using System.Threading;
using System.Text;
using System.Collections.Generic;
using System.Linq;
using HeyRed.Mime;
using Newtonsoft.Json;
using System.Security.Cryptography.X509Certificates;
using System.Net.Security;
using System.Security.Authentication;

namespace Tesses.WebServer
{
   
    public static class Extensions
    {     
        /// <summary>
        /// Read string from request body
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <returns>the contents of request</returns>
        public static async Task<string> ReadStringAsync(this ServerContext ctx)
        {
            string str = null;
            using (var reader = new StreamReader(ctx.NetworkStream))
            {
                str = await reader.ReadToEndAsync();
            }

            return str;
        }
        /// <summary>
        /// Read json from request body
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <typeparam name="T">type of object (for scema)</typeparam>
        /// <returns>object of type T with deserialized json data</returns>
        public static async Task<T> ReadJsonAsync<T>(this ServerContext ctx)
        {
            var json=await ctx.ReadStringAsync();
            return JsonConvert.DeserializeObject<T>(json);
        }
        /// <summary>
        /// Read request body to array
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <returns>Request body data</returns>
        public static async Task<byte[]> ReadBytesAsync(this ServerContext ctx)
        {
            MemoryStream strm = new MemoryStream();
            await ctx.ReadToStreamAsync(strm);
            return strm.ToArray();
        }
        /// <summary>
        /// Read request body to stream
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <param name="strm">Stream to write to</param>
        
        public static async Task ReadToStreamAsync(this ServerContext ctx,Stream strm)
        {
                 await ctx.NetworkStream.CopyToAsync(strm);
        }
        /// <summary>
        /// Read request body to file
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <param name="filename">name of file to write too, can be without extension</param>
        /// <returns>file path with extension unless mimetype header is missing</returns>
        public static async Task<string> ReadToFileAsync(this ServerContext ctx,string filename)
        {
            if(string.IsNullOrWhiteSpace(Path.GetExtension(filename)))
            {
                string val;
                if(ctx.RequestHeaders.TryGetFirst("Content-Type",out val))
                {
                    filename += $".{MimeTypesMap.GetExtension(val)}";
                }
                
            }
            using(var f = File.Create(filename))
            {
                await ctx.NetworkStream.CopyToAsync(f);
            }
            return filename;
        }

        /// <summary>
        /// Write headers to stream
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        
        public static async Task WriteHeadersAsync(this ServerContext ctx)
        {
            string status_line = $"HTTP/1.1 {ctx.StatusCode} {StatusCodeMap.GetStatusString(ctx.StatusCode)}\r\n";
            StringBuilder b = new StringBuilder(status_line);
            foreach (var hdr in ctx.ResponseHeaders)
            {
                foreach (var v in hdr.Value)
                {
                    b.Append($"{hdr.Key}: {v}\r\n");
                }
            }
            b.Append("\r\n");
            var data = Encoding.UTF8.GetBytes(b.ToString());
            await ctx.NetworkStream.WriteAsync(data, 0, data.Length);
        }
        /// <summary>
        /// Send file to client (supports range partial content)
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <param name="file">the file to serve</param>
        
        public static async Task SendFileAsync(this ServerContext ctx, string file)
        {
            using (var strm = File.OpenRead(file))
            {
                await ctx.SendStreamAsync( strm, MimeTypesMap.GetMimeType(file));
            }
        }
        /// <summary>
        /// Send exception to client
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <param name="ex">the Exception</param>
        
        public static async Task SendExceptionAsync(this ServerContext ctx, Exception ex)
        {
            string name = ex.GetType().FullName;
            string j = $"<html><head><title>{WebUtility.HtmlEncode(name)} thrown</title></head><body><h1>{WebUtility.HtmlEncode(name)} thrown</h1><h3>Description: {WebUtility.HtmlEncode(ex.Message)}</h3></body></html>";
            ctx.StatusCode = 500;
            await ctx.SendTextAsync(j);
        }
        /// <summary>
        /// Send object as json to client
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <param name="value">an object to serialize with newtonsoft.json</param>
        public static async Task SendJsonAsync(this ServerContext ctx,object value)
        {
            await ctx.SendTextAsync(JsonConvert.SerializeObject(value), "application/json");
        }
        /// <summary>
        /// Send text to client
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <param name="data">some text</param>
        /// <param name="contentType">mime type</param>
        
        public static async Task SendTextAsync(this ServerContext ctx, string data, string contentType = "text/html")
        {
            await ctx.SendBytesAsync(Encoding.UTF8.GetBytes(data), contentType);
        }
        /// <summary>
        /// Send redirect
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <param name="url">Url to redirect to</param>
        public static async Task SendRedirectAsync(this ServerContext ctx,string url)
        {
            ctx.StatusCode = 301;
            ctx.ResponseHeaders.Add("Cache-Control","no-cache");
            ctx.ResponseHeaders.Add("Location",url);
            await ctx.WriteHeadersAsync();
        }
        /// <summary>
        /// Send byte[] to client
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <param name="array">a byte[] array</param>
        /// <param name="contentType">mime type</param>
        public static async Task SendBytesAsync(this ServerContext ctx, byte[] array, string contentType = "application/octet-stream")
        {
            using (var ms = new MemoryStream(array))
            {
                await ctx.SendStreamAsync( ms, contentType);
            }
        }
        /// <summary>
        /// Get first item in Dictionary<T1,List<T2>> based on key
        /// </summary>
        /// <param name="args">the dictionary with list<T2> value</param>
        /// <param name="key">some key</param>
        /// <typeparam name="T1">key type</typeparam>
        /// <typeparam name="T2">value type</typeparam>
        /// <returns></returns>
        public static T2 GetFirst<T1,T2>(this Dictionary<T1,List<T2>> args,T1 key)
        {
            return args[key][0];
        }
        /// <summary>
        /// Try to get first item in  Dictionary<T1,List<T2>> based on key
        /// </summary>
        /// <param name="args">the dictionary with list<T2> value</param>
        /// <param name="key">the key to check</param>
        /// <param name="value">the value returned</param>
        /// <typeparam name="T1">key type</typeparam>
        /// <typeparam name="T2">value type</typeparam>
        /// <returns>true if found else false if not found</returns>
        public static bool TryGetFirst<T1,T2>(this Dictionary<T1,List<T2>> args,T1 key,out T2 value)
        {
            List<T2> ls;
            if (args.TryGetValue(key,out ls))
            {
                if(ls.Count > 0)
                {
                    value = ls[0];
                    return true;
                }
            }
            value = default(T2);
            return false;
        }
        /// <summary>
        /// Add item to the Dictionary<T1,List<T2>> with specified key (will create key in dictionary if not exist)
        /// </summary>
        /// <param name="list">the dictionary with list<T2> value</param>
        /// <param name="key">the key to add or to add to</param>
        /// <param name="item">a item</param>
        /// <typeparam name="T1">key type</typeparam>
        /// <typeparam name="T2">value type</typeparam>
        public static void Add<T1,T2>(this Dictionary<T1,List<T2>> list,T1 key,T2 item)
        {
            if (list.ContainsKey(key))
            {
                list[key].Add(item);
            }
            else
            {
                List<T2> items = new List<T2>();
                items.Add(item);
                list.Add(key, items);
            }
        }
        /// <summary>
        /// Add multiple items to the Dictionary<T1,List<T2>> with specified key (will create key in dictionary if not exist)
        /// </summary>
        /// <param name="list">the dictionary with list<T2> value</param>
        /// <param name="key">the key to add or to add to</param>
        /// <param name="items">IEnumerable<T2></param>
        /// <typeparam name="T1">key type</typeparam>
        /// <typeparam name="T2">value type</typeparam>
        public static void AddRange<T1,T2>(this Dictionary<T1,List<T2>> list,T1 key,IEnumerable<T2> items)
        {
            if (list.ContainsKey(key))
            {
                list[key].AddRange(items);
            }
            else
            {
                List<T2> items2 = new List<T2>();
                items2.AddRange(items);
                list.Add(key, items2);

            }
        }
        /// <summary>
        /// StringBuilder ends with
        /// </summary>
        /// <param name="sb">string builder</param>
        /// <param name="test">text to check</param>
        /// <param name="comparison">comparison type</param>
        /// <returns>true if sb ends with test, false if it does not</returns>
        public static bool EndsWith(this StringBuilder sb, string test,
    StringComparison comparison)
        {
            if (sb.Length < test.Length)
                return false;

            string end = sb.ToString(sb.Length - test.Length, test.Length);
            return end.Equals(test, comparison);
        }
    }
    /// <summary>
    /// returns 404 not found page
    /// </summary>
    public class NotFoundServer : Server
    {
        /// <summary>
        /// 404 not found custom html use "{url}" in your html as url
        /// </summary>
        /// <param name="html">the custom html</param>
        public NotFoundServer(string html)
        {
            _html = html;
        }
        /// <summary>
        ///404 not found default html
        /// </summary>
        public NotFoundServer()
        {
            _html = "<html><head><title>File {url} not found</title></head><body><h1>404 Not Found</h1><h4>{url}</h4></body></html>";
        }
        string _html;
        public override async Task GetAsync(ServerContext ctx)
        {
            ctx.StatusCode = 404;
            await ctx.SendTextAsync( _html.Replace("{url}", WebUtility.HtmlEncode(ctx.OriginalUrlPath)));
        }
    }
    /// <summary>
    /// Serve static files (doesnt allow listing files)
    /// </summary>
    public class StaticServer : Server
    {
        string _path;
        IServer _server;
        /// <summary>
        /// construct with path
        /// </summary>
        /// <param name="path">directory for server</param>
        public StaticServer(string path)
        {
            _path = path;
            _server = new NotFoundServer();
            _defaultFileNames = new string[] {"index.html","index.htm","default.html","default.htm" };
        }
        string[] _defaultFileNames;
        /// <summary>
        /// construct with path, custom filenames, and server for not found
        /// </summary>
        /// <param name="path">directory for server</param>
        /// <param name="defaultFileNames">like index.html, index.htm, default.html, default.htm</param>
        /// <param name="notfoundserver">404 not found server</param>
        public StaticServer(string path,string[] defaultFileNames,IServer notfoundserver)
        {
            _path = path;
            _server = notfoundserver;
            _defaultFileNames = defaultFileNames;
        }
        public bool DefaultFileExists(string path,out string name)
        {
            foreach(var def in _defaultFileNames)
            {
                name = Path.Combine(path, def);
                if(File.Exists(name))
                {
                    return true;
                }
            }
            name = "";
            return false;
        }


        public override async Task GetAsync(ServerContext ctx)
        {
            string someUrl = Path.Combine(_path,WebUtility.UrlDecode(ctx.UrlPath.Substring(1)).Replace('/', Path.DirectorySeparatorChar));
            //Console.WriteLine(someUrl);
            if (Directory.Exists(someUrl))
            {
                string name;
                if(DefaultFileExists(someUrl,out name))
                {
                    await ctx.SendFileAsync(name);
                }
            }
            else if (File.Exists(someUrl))
            {
                await ctx.SendFileAsync(someUrl);
            }
            else
            {
                await _server.GetAsync(ctx);
            }
        }

    }
    /// <summary>
    /// Server where you can change inner server
    /// </summary>
    public class ChangeableServer : Server
    {
        /// <summary>
        /// The inner server to change
        /// </summary>
        
        public IServer Server {get;set;}
        /// <summary>
        /// Construct with default value
        /// </summary>
        public ChangeableServer()
        {
            Server=null;
        }
        /// <summary>
        /// Construct with server
        /// </summary>
        /// <param name="svr">the inner server</param>
        public ChangeableServer(IServer svr)
        {
            Server=svr;
        }

        public override async Task<bool> BeforeAsync(ServerContext ctx)
        {
            return await Guaranteed(Server).BeforeAsync(ctx);
        }

        public override async Task GetAsync(ServerContext ctx)
        {
            await Guaranteed(Server).GetAsync(ctx);
        }

        public override async Task OptionsAsync(ServerContext ctx)
        {
            await Guaranteed(Server).OptionsAsync(ctx);
        }

        public override async Task OtherAsync(ServerContext ctx)
        {
            await Guaranteed(Server).OtherAsync(ctx);
        }

        public override async Task PostAsync(ServerContext ctx)
        {
            await Guaranteed(Server).PostAsync(ctx);
        }
    }
    /// <summary>
    /// Abstract class for server
    /// </summary>
    public abstract class Server : IServer
    {
        /// <summary>
        /// Returns 404 Not found
        /// </summary>
        
        public static readonly NotFoundServer ServerNull = new NotFoundServer();
        /// <summary>
        /// You are guarenteed to have a server
        /// </summary>
        /// <param name="svr">any server object</param>
        /// <returns>if null return ServerNull otherwise return svr</returns>
        public IServer Guaranteed(IServer svr)
        {
            if(svr != null)
            {
                return svr;
            }
            return ServerNull;
        }
        /// <summary>
        /// Put cors header
        /// </summary>
        public bool CorsHeader = true;
        /// <summary>
        /// Called on GET Request
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        public abstract Task GetAsync(ServerContext ctx);
         /// <summary>
        /// Called on POST Request
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        public virtual async Task PostAsync(ServerContext ctx)
        {
            ctx.StatusCode = (int)HttpStatusCode.MethodNotAllowed;
            await ctx.SendTextAsync("Method Not Supported");
        
        }
        /// <summary>
        /// Called on OPTIONS Request
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        
        public virtual async Task OptionsAsync(ServerContext ctx)
        {
            await ctx.WriteHeadersAsync();
            ctx.NetworkStream.Close();
        }
         /// <summary>
        /// Called on any other Request method
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        public virtual async Task OtherAsync(ServerContext ctx)
        {
            ctx.StatusCode = (int)HttpStatusCode.MethodNotAllowed;
            await ctx.SendTextAsync("Method Not Supported");

        }
        /// <summary>
        /// Called before request was made
        /// </summary>
        /// <param name="ctx">ServerContext</param>
        /// <returns>true to cancel request, false to continue request</returns>
        public virtual async Task<bool> BeforeAsync(ServerContext ctx)
        {

            return await Task.FromResult(false);
        }
        /// <summary>
        /// Add cors header
        /// </summary>
        /// <param name="ctx">Server Context</param>
        public void AddCors(ServerContext ctx)
        {
            if (CorsHeader)
            {

                ctx.ResponseHeaders.Add("Access-Control-Allow-Origin", "*");
                ctx.ResponseHeaders.Add("Access-Control-Allow-Headers", "Cache-Control, Pragma, Accept, Origin, Authorization, Content-Type, X-Requested-With");
                ctx.ResponseHeaders.Add("Access-Control-Allow-Methods", "GET, POST");
                ctx.ResponseHeaders.Add("Access-Control-Allow-Credentials", "true");

            }
        }
    }
    /// <summary>
    /// mount multiple servers at different url paths
    /// </summary>
    public sealed class MountableServer : Server
    {
        Dictionary<string, IServer> _servers = new Dictionary<string, IServer>();
        public MountableServer(IServer root)
        {
            _root = root;
        }
        IServer _root;
        private (string Key,IServer Value) GetFromPath(ServerContext ctx)
        {
            //bool j = false;
           foreach(var item in _servers.Reverse())
            {
                if(ctx.UrlPath.StartsWith(item.Key,StringComparison.Ordinal))
                {
                    return (item.Key,Guaranteed(item.Value));
                }
                if (ctx.UrlPath == item.Key.TrimEnd('/'))
                {
                    ctx.UrlPath += "/";
                    return (item.Key,Guaranteed(item.Value));
                }
            }
            //Console.WriteLine("HERE WE ARE");
            return ("/",Guaranteed(_root));
        }
        /// <summary>
        /// Mount the specified url and server.
        /// Must mount like this
        /// /somePath0
        /// /somePath0/someSubPath0
        /// /somePath0/someSubPath0/someSubSubPath0
        /// /somePath0/someSubPath0/someSubSubPath1
        /// /somePath0/someSubPath1
        /// /somePath0/someSubPath1/someSubSubPath0
        /// /somePath0/someSubPath1/someSubSubPath1
        /// </summary>
        /// <param name="url">URL.</param>
        /// <param name="server">Server.</param>
        public void Mount(string url,IServer server)
        {
            _servers.Add(url, server);
        }
        /// <summary>
        /// Unmount a server
        /// </summary>
        /// <param name="url">Url</param>
        public void Unmount(string url)
        {
            _servers.Remove(url);
        }
        /// <summary>
        /// Unmount all servers
        /// </summary>
        public void UnmountAll()
        {
            _servers.Clear();
        }
        public override async Task GetAsync(ServerContext ctx)
        {
            var v = GetFromPath(ctx);
            string url = '/' + ctx.UrlPath.Substring(v.Key.Length).TrimStart('/');
            ctx.UrlPath = url;

            await v.Value.GetAsync(ctx);
        }
        public override async Task PostAsync(ServerContext ctx)
        {
            var v = GetFromPath(ctx);
            string url = '/' + ctx.UrlPath.Substring(v.Key.Length).TrimStart('/');
            ctx.UrlPath = url;

            await v.Value.PostAsync(ctx);
        }
        public override async Task<bool> BeforeAsync(ServerContext ctx)
        {
            var v = GetFromPath(ctx);
            string old=ctx.UrlPath;
            string url = '/' + ctx.UrlPath.Substring(v.Key.Length).TrimStart('/');
            ctx.UrlPath = url;

            var res=await v.Value.BeforeAsync(ctx);
            ctx.UrlPath = old;
            return res;
        }
        public override async Task OptionsAsync(ServerContext ctx)
        {
            var v = GetFromPath(ctx);
            string url = '/' + ctx.UrlPath.Substring(v.Key.Length).TrimStart('/');
            ctx.UrlPath = url;

            await v.Value.OptionsAsync(ctx);
        }
        public override async Task OtherAsync(ServerContext ctx)
        {
            var v = GetFromPath(ctx);
            string url = '/' + ctx.UrlPath.Substring(v.Key.Length).TrimStart('/');
            ctx.UrlPath = url;

            await v.Value.OtherAsync(ctx);
        }
    }
    /// <summary>
    /// Check username and password are correct or if request can be anonymous
    /// </summary>
    /// <param name="username">Username, can and will be "" on first request for resource</param>
    /// <param name="password">Password, can and will be "" on first request for resource</param>
    /// <returns>true for authorized, false for unauthorized</returns>
    public delegate bool Authenticate(string username, string password);
    /// <summary>
    /// Check username and password are correct or if request can be anonymous
    /// </summary>
    /// <param name="context">Server Context</param>
    /// <param name="username">Username, can and will be "" on first request for resource</param>
    /// <param name="password">Password, can and will be "" on first request for resource</param>
    /// <returns>true for authorized, false for unauthorized</returns>
    public delegate bool AuthenticateWithContext(ServerContext context,string username,string password);
    /// <summary>
    /// Protect server with password
    /// </summary>
    public class BasicAuthServer : Server
    {
        /// <summary>
        /// Construct server for user authorization
        /// </summary>
        /// <param name="auth">callback for authorization</param>
        /// <param name="inner">server to protect</param>
        /// <param name="realm">realm parameter in WWW-Auhenticate Header</param>
        public BasicAuthServer(Authenticate auth,IServer inner,string realm="SampleRealm")
        {
            Authenticate = auth;
            InnerServer = inner;
            Realm = realm;
        }
         /// <summary>
        /// Construct server for user authorization (With ServerContext in callback)
        /// </summary>
        /// <param name="auth">callback for authorization</param>
        /// <param name="inner">server to protect</param>
        /// <param name="realm">realm parameter in WWW-Auhenticate Header</param>
        public BasicAuthServer(AuthenticateWithContext auth,IServer inner,string realm = "SampleRealm")
        {
            AuthenticateWithContext=auth;
            InnerServer=inner;
            Realm = realm;
        }
        public override async Task<bool> BeforeAsync(ServerContext ctx)
        {
            if(await Authorize(ctx))
            {
               
                    return await Guaranteed(InnerServer).BeforeAsync(ctx);

            }
            return true;
        }
        public override async Task GetAsync(ServerContext ctx)
        {

                await Guaranteed(InnerServer).GetAsync(ctx);

        }
        public override async Task PostAsync(ServerContext ctx)
        {

                await Guaranteed(InnerServer).PostAsync(ctx);

        }

        public override async Task OtherAsync(ServerContext ctx)
        {

                await Guaranteed(InnerServer).OtherAsync(ctx);

        }
        public override async Task OptionsAsync(ServerContext ctx)
        {
          
                await Guaranteed(InnerServer).OptionsAsync(ctx);

        }
        /// <summary>
        /// Server to protect
        /// </summary>
        
        public IServer InnerServer { get; set; }
        /// <summary>
        /// Authentication callback without ServerContext
        /// </summary>
        public Authenticate Authenticate { get; set; }
        /// <summary>
        /// Authentication callback with ServerContext
        /// </summary>
    
        public AuthenticateWithContext AuthenticateWithContext {get;set;}
        /// <summary>
        /// Realm parameter in WWW-Authenticate header
        /// </summary>
        public string Realm { get; set; }
       
        private bool ValidAuth(ServerContext ctx)
        {
            string auth;
            if(Authenticate == null && AuthenticateWithContext == null) return true;
            if (ctx.RequestHeaders.TryGetFirst("Authorization", out auth))
            {
                string[] authorization = auth.Split(' ');
                //authorization_basic

                if (authorization[0] == "Basic")
                {
                    string[] userPass = Encoding.UTF8.GetString(Convert.FromBase64String(authorization[1])).Split(new char[] { ':' },2);
                    //return userPass.Equals($"{config.UserName}:{config.Password}", StringComparison.Ordinal);
                    if(Authenticate != null)
                        return Authenticate(userPass[0], userPass[1]); 

                    if(AuthenticateWithContext != null)
                        return AuthenticateWithContext(ctx,userPass[0],userPass[2]);

                   
                }
            }else{
                  if(Authenticate != null)
                        return Authenticate("", ""); 

                    if(AuthenticateWithContext != null)
                        return AuthenticateWithContext(ctx,"","");

            }
            return false;
        }
        private async Task<bool> Authorize(ServerContext ctx)
        {
            if (Authenticate == null && AuthenticateWithContext == null)
                return true;

            if (ValidAuth(ctx))
                return true;

            ctx.ResponseHeaders.Add("WWW-Authenticate", $"Basic realm=\"{Realm}\"");
            ctx.StatusCode = 401;
            await UnauthorizedPage(ctx);
            return false;
        }
        protected virtual async Task UnauthorizedPage(ServerContext ctx)
        {
            await ctx.SendTextAsync("Unauthorized");
        }
    }
    public class HostDomainServer : Server
    {
        public HostDomainServer(IServer alt)
        {
            Default = alt;
            Servers = new Dictionary<string, IServer>();
        }
        public void Clear()
        {
            Servers.Clear();
        }
        public void Remove(string fqdn_or_ip)
        {
            Servers.Remove(fqdn_or_ip);
        }
        public IServer Default { get; set; }
        Dictionary<string, IServer> Servers;

        public void AddDomain(string fqdn_or_ip,IServer svr)
        {
            Servers.Add(fqdn_or_ip, svr);
        }
        public override async Task<bool> BeforeAsync(ServerContext ctx)
        {
           return await GetDomain(ctx).BeforeAsync(ctx);
           
        }
        public override async Task PostAsync(ServerContext ctx)
        {
            await GetDomain(ctx).PostAsync(ctx);
        }
        public override async Task OtherAsync(ServerContext ctx)
        {
            await GetDomain(ctx).OtherAsync(ctx);
        }
        public override async Task OptionsAsync(ServerContext ctx)
        {
            await GetDomain(ctx).OptionsAsync(ctx);
        }
        public override async Task GetAsync(ServerContext ctx)
        {
            await GetDomain(ctx).GetAsync(ctx);
        }
        private IServer GetDomain(ServerContext ctx)
        {
            string fqdn_or_ip = ctx.Host;
            foreach(var item in Servers)
            {
                if(item.Key.Equals(fqdn_or_ip,StringComparison.Ordinal))
                {
                    return Guaranteed(item.Value);
                }
            }
            return Guaranteed(Default);
        
        }
         
    }
    public interface IServer
    {
        void AddCors(ServerContext ctx);
        Task<bool> BeforeAsync(ServerContext ctx);
        Task GetAsync(ServerContext ctx);
        Task PostAsync(ServerContext ctx);
        Task OptionsAsync(ServerContext ctx);
        Task OtherAsync(ServerContext ctx);
    }

    public sealed class HttpServerListener
    {
        /// <summary>
        /// Print urls when running
        /// </summary>
        /// <value>true if verbose, false if not</value>
        public bool PrintUrls {get;set;}
        bool https;
        X509Certificate cert;
        IServer _server;
        TcpListener _listener;
        SslProtocols protocols;

        public HttpServerListener(IPEndPoint endPoint,IServer server)
        {
            _listener = new TcpListener(endPoint);
            _server = server;
            https = false;
            PrintUrls=false;
        }
        public HttpServerListener(IServer server)
        {
            _listener = new TcpListener(new IPEndPoint(IPAddress.Any, 3251));
            _server = server;
            https = false;
            PrintUrls=false;
        }
        public HttpServerListener(IPEndPoint endpoint,IServer server,X509Certificate cert,SslProtocols protocols=SslProtocols.Default)
        {
            _listener = new TcpListener(endpoint);
            _server = server;
            https = cert != null;
            this.cert = cert;
            this.protocols=protocols;
            PrintUrls=false;
        }
        public async Task ListenAsync(CancellationToken token)
        {
            _listener.Start();
            using (var r = token.Register(() => _listener.Stop())) { 
            while (!token.IsCancellationRequested)
                {
                    var socket=await _listener.AcceptTcpClientAsync();
                    await CommunicateHostAsync(socket).ConfigureAwait(false);
                }
            }
        }
        
        private string ReadHeaders(Stream strm)
        {
            StringBuilder s = new StringBuilder();

            var decoder = Encoding.UTF8.GetDecoder();
            var nextChar = new char[1];
            while (!s.EndsWith("\r\n\r\n",StringComparison.Ordinal))
            {
                int data = strm.ReadByte();
                if(data == -1)
                {
                    break;
                }
                int charCount=decoder.GetChars(new byte[] { (byte)data }, 0, 1, nextChar, 0);
                if (charCount == 0) continue;
                s.Append(nextChar);
            }

            return s.ToString();
        }
        

        private Dictionary<string,List<string>> Headers(string s,out string req_line)
        {

            Dictionary<string, List<string>> items = new Dictionary<string, List<string>>();
            string[] lines = s.Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
            req_line = lines[0];
            for(int i=1;i<lines.Length;i++)
            {
                var line_split=lines[i].Split(new[] { ": " },2,StringSplitOptions.None);
                if (line_split.Length == 2)
                {
                    items.Add(line_split[0], line_split[1]);
                }
            }
            return items;
        }
        public Stream GetStream(TcpClient clt)
        {
            if(https)
            {
                SslStream sslStream = new SslStream(
                clt.GetStream(), false);
                try
                {
                    sslStream.AuthenticateAsServer(cert,false,protocols,true);

                }
                catch (Exception ex)
                {
                    _ = ex;
                }
                return sslStream;
            }
            return clt.GetStream();
        }
        private async Task CommunicateHostAsync(TcpClient clt)
        {
            //<METHOD> <PATH> HTTP/1.1\r\n
            //HEADER1\r\n
            //HEADER2\r\n
            //......
            //HEADERN\r\n
            //\r\n
            //OPTIONAL REQUEST BODY

            //RESPONSE

            using (Stream strm = GetStream(clt))
            {

                string request_line = "";
                string res=ReadHeaders(strm);
                var headers=Headers(res,out request_line);

                // {Method} {Path} HTTP/1.1
                ServerContext ctx=null;
                string[] request=request_line.Split(new char[] { ' ' }, 3);
                string method = request[0];
                try
                {
                    string path = request[1];
                    string ver = request[2];
                    ctx = new ServerContext(method, strm, path, headers);
                    ctx.Server = clt.Client.LocalEndPoint as IPEndPoint;
                    ctx.Client = clt.Client.RemoteEndPoint as IPEndPoint;
                    _server.AddCors(ctx);
                    if(PrintUrls)
                    {
                        Console.WriteLine(path);
                    }
                    if (!await _server.BeforeAsync(ctx))
                    {
                        switch (method)
                        {
                            case "HEAD":
                            case "GET":

                                await _server.GetAsync(ctx);
                                break;
                            case "POST":
                                await _server.PostAsync(ctx);
                                break;
                            case "OPTIONS":
                                await _server.OptionsAsync(ctx);
                                break;
                            default:
                                await _server.OtherAsync(ctx);
                                break;
                        }
                    }
                }catch(Exception ex)
                {
                    try
                    {
                        await ctx.SendExceptionAsync(ex);
                    }catch(Exception ex2)
                    {
                        _ = ex2;
                    }
                }

            }


        }
      
        //protected abstract Task<IResult> Get(string url,Dictionary<string,string> headers);  

        //protected abstract Task GetAsync(ServerContext ctx);
    }
}