using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Net;
using System.Runtime.InteropServices;
using System.Text.RegularExpressions;
using Tesses.WebServer;
namespace Ooui
{
    public class UI : Server
    {
        public bool Verbose {get;set;}=true;
        private async Task HandleAsync(ServerContext ctx)
        {
             string upgrade;
                if(ctx.RequestHeaders.TryGetFirst("Upgrade",out upgrade) && upgrade == "websocket")
                {
                    ProcessWebSocketRequest (ctx, CancellationToken.None);
                    
                }
                else
                {
                    ProcessRequest(ctx,CancellationToken.None);
                }
                await Task.FromResult(0);
        }
        public override async Task GetAsync(ServerContext ctx)
        {
           
           await HandleAsync(ctx);
        }
        public override async Task OptionsAsync(ServerContext ctx)
        {
            await HandleAsync(ctx);
        }
        public override async Task PostAsync(ServerContext ctx)
        {
           await HandleAsync(ctx);
        }
        public override async Task OtherAsync(ServerContext ctx)
        {
            await HandleAsync(ctx);
        }
        public const int MaxFps = 30;

        static readonly ManualResetEvent started = new ManualResetEvent (false);

        //static CancellationTokenSource serverCts;

        static readonly Dictionary<string, PublishedPath> publishedPaths =
            new Dictionary<string, PublishedPath> ();

        static readonly byte[] clientJsBytes;
        static readonly string clientJsEtag;

        public static byte[] ClientJsBytes => clientJsBytes;
        public static string ClientJsEtag => clientJsEtag;

        public static string HeadHtml { get; set; } = @"<link rel=""stylesheet"" href=""https://ajax.aspnetcdn.com/ajax/bootstrap/3.3.7/css/bootstrap.min.css"" />";
        public static string BodyHeaderHtml { get; set; } = @"";
        public static string BodyFooterHtml { get; set; } = @"";

       
       
       
        static UI ()
        {
            var asm = typeof(UI).Assembly;
            // System.Console.WriteLine("ASM = {0}", asm);
            // foreach (var n in asm.GetManifestResourceNames()) {
            //     System.Console.WriteLine("  {0}", n);
            // }
            using (var s = asm.GetManifestResourceStream ("Ooui.Client.js")) {
				if (s == null)
					throw new Exception ("Missing Client.js");
                using (var r = new StreamReader (s)) {
                    clientJsBytes = Encoding.UTF8.GetBytes (r.ReadToEnd ());
                }
            }
            clientJsEtag = "\"" + Utilities.GetShaHash (clientJsBytes) + "\"";
        }

        class PublishedPath
        {
            public string Path { get; }
            public Regex RegexPath { get; }
            public RequestHandler Handler { get; }
            public PublishedPath (string path, RequestHandler handler)
            {
                Path = path;
                RegexPath = new Regex ("^" + path + "$");
                Handler = handler;
            }
        }

         void Publish (string path, RequestHandler handler)
        {
            //Console.WriteLine ($"PUBLISH {path} {handler}");
            lock (publishedPaths) publishedPaths[path] = new PublishedPath (path, handler);
            
        }

        public void Publish (string path, Func<UIContext, Element> elementCtor, bool disposeElementWhenDone = true)
        {
            Publish (path, new ElementHandler (elementCtor, disposeElementWhenDone));
        }

        public void Publish (string path, Func<Element> elementCtor, bool disposeElementWhenDone = true)
        {
            Publish (path, new ElementHandler (_ => elementCtor (), disposeElementWhenDone));
        }

        public void Publish (string path, Element element, bool disposeElementWhenDone = true)
        {
            Publish (path, () => element, disposeElementWhenDone);
        }

        public void PublishFile (string filePath)
        {
            var path = "/" + System.IO.Path.GetFileName (filePath);
            PublishFile (path, filePath);
        }

        public void PublishFile (string path, string filePath, string contentType = null)
        {
            var data = System.IO.File.ReadAllBytes (filePath);
            if (contentType == null) {
                contentType = GuessContentType (path, filePath);
            }
            var etag = "\"" + Utilities.GetShaHash (data) + "\"";
            Publish (path, new DataHandler (data, etag, contentType));
        }

        public void PublishFile (string path, byte[] data, string contentType)
        {
            var etag = "\"" + Utilities.GetShaHash (data) + "\"";
            Publish (path, new DataHandler (data, etag, contentType));
        }

        public void PublishFile (string path, byte[] data, string etag, string contentType)
        {            
            Publish (path, new DataHandler (data, etag, contentType));
        }

        public bool TryGetFileContentAtPath (string path, out FileContent file)
        {
            PublishedPath pp;
            lock (publishedPaths) {
                if (!publishedPaths.TryGetValue (path, out pp)) {
                    file = null;
                    return false;
                }
            }
            if (pp.Handler is DataHandler dh) {
                file = new FileContent {
                    Etag = dh.Etag,
                    Content = dh.Data,
                    ContentType = dh.ContentType,
                };
                return true;
            }
            file = null;
            return false;
        }

        public class FileContent
        {
            public string ContentType { get; set; }
            public string Etag { get; set; }
            public byte[] Content { get; set; }
        }

        public void PublishJson (string path, Func<object> ctor)
        {
            Publish (path, new JsonHandler (_ => ctor ()));
        }

        public void PublishJson (string path, Func<UIContext, object> ctor)
        {
            Publish (path, new JsonHandler (ctor));
        }

        public  void PublishJson (string path, object value)
        {
            var data = JsonHandler.GetData (value);
            var etag = "\"" + Utilities.GetShaHash (data) + "\"";
            Publish (path, new DataHandler (data, etag, JsonHandler.ContentType));
        }

		public void PublishCustomResponse (string path, Action<ServerContext, CancellationToken> responder)
		{
			Publish (path, new CustomHandler (responder));
		}

        static string GuessContentType (string path, string filePath)
        {
            return null;
        }

      
       
        

       // public static void WaitUntilStarted () => started.WaitOne ();

       

        

        
      
        void ProcessRequest (ServerContext listenerContext, CancellationToken token)
        {
            var path = listenerContext.UrlPath;
            
            if(this.Verbose)
            Console.WriteLine ($"{listenerContext.Method} {path}");

            

            if (path == "/ooui.js") {
                string inm="";
                listenerContext.RequestHeaders.TryGetFirst ("If-None-Match",out inm);
                if (   string.IsNullOrEmpty (inm) || inm != clientJsEtag) {
                    listenerContext.StatusCode = 200;
                    
                    
                   
                    listenerContext.ResponseHeaders.Add ("Cache-Control", "public, max-age=60");
                    listenerContext.ResponseHeaders.Add ("Etag", clientJsEtag);
                    
                    listenerContext.SendBytes(clientJsBytes,"appllication/json");
                    
                }
                else {
                    listenerContext.StatusCode=304;
                    listenerContext.WriteHeaders();
                    listenerContext.NetworkStream.Close();
                }
            }
            else {
                var found = false;
                PublishedPath pp;
                var variables = new Dictionary<string, string> ();
                lock (publishedPaths) found = publishedPaths.TryGetValue (path, out pp);
                
                if (!found) {
                    // Try regex
                    List<PublishedPath> pps;
                    lock (publishedPaths) pps = publishedPaths.Values.ToList();
                    foreach (var p in pps) {
                        var m = p.RegexPath.Match (path);
                        if (m.Success) {
                            pp = p;
                            found = true;
                            for (var ig = 1; ig < m.Groups.Count; ig++) {
                                variables[p.RegexPath.GroupNameFromNumber(ig)] = m.Groups[ig].Value;
                            }
                            break;
                        }
                    }
                }
                if (found) {
                    try {
                        var context = UIContext.ForListenerContext (listenerContext, variables);
                        pp.Handler.Respond (listenerContext, context, token);
                    }
                    catch (Exception ex) {
                        Error ("Handler failed to respond", ex);
                        try {
                            listenerContext.StatusCode = 500;
                            listenerContext.WriteHeaders();
                            listenerContext.NetworkStream.Close ();
                        }
                        catch {
                            // Ignore ending the response errors
                        }
                    }
                }
                else {
                    listenerContext.StatusCode = 500;
                            listenerContext.WriteHeaders();
                            listenerContext.NetworkStream.Close ();
                    
                }
            }
        }

        abstract class RequestHandler
        {
            public abstract void Respond (ServerContext listenerContext, UIContext context, CancellationToken token);
        }

        class ElementHandler : RequestHandler
        {
            readonly Func<UIContext, Element> ctor;

            public bool DisposeElementWhenDone { get; }

            public ElementHandler (Func<UIContext, Element> ctor, bool disposeElementWhenDone)
            {
                this.ctor = ctor;
                DisposeElementWhenDone = disposeElementWhenDone;
            }

            public Element GetElement (UIContext context) => ctor (context);

            public override void Respond (ServerContext listenerContext, UIContext context, CancellationToken token)
            {
                var path = listenerContext.UrlPath;
                
                listenerContext.StatusCode = 200;
              listenerContext.SendText(RenderTemplate (path));
               
            }
        }

        public static string RenderTemplate (string webSocketPath, string title = "", string initialHtml = "")
        {
            using (var w = new System.IO.StringWriter ()) {
                RenderTemplate (w, webSocketPath, title, initialHtml);
                return w.ToString ();
            }
        }

        static string EscapeHtml (string text)
        {
            return text.Replace ("&", "&amp;").Replace ("<", "&lt;");
        }

        public static void RenderTemplate (TextWriter writer, string webSocketPath, string title, string initialHtml)
        {
            writer.Write (@"<!DOCTYPE html>
<html>
<head>
  <title>");
            writer.Write (EscapeHtml (title));
            writer.Write (@"</title>
  <meta name=""viewport"" content=""width=device-width, initial-scale=1"" />
  ");
            writer.WriteLine (HeadHtml);
            writer.WriteLine (@"  <style>");
            writer.WriteLine (rules.ToString ());
            writer.WriteLine (@"  </style>
</head>
<body>");
            writer.WriteLine (BodyHeaderHtml);
            writer.WriteLine (@"<div id=""ooui-body"" class=""container-fluid"" style=""padding:0;margin:0"">");
            writer.WriteLine (initialHtml);
            writer.Write (@"</div>

<script src=""/ooui.js""></script>
<script>ooui(""");
            writer.Write (webSocketPath);
            writer.WriteLine (@""");</script>");
            writer.WriteLine (BodyFooterHtml);
            writer.WriteLine (@"</body>
</html>");
        }

        class DataHandler : RequestHandler
        {
            readonly byte[] data;
            readonly string etag;
            readonly string contentType;

            public byte[] Data => data;
            public string Etag => etag;
            public string ContentType => contentType;

            public DataHandler (byte[] data, string etag, string contentType = null)
            {
                this.data = data;
                this.etag = etag;
                this.contentType = contentType;
            }

            public override void Respond (ServerContext listenerContext, UIContext context, CancellationToken token)
            {
                var url = listenerContext.UrlPath;
               

               string inm="";
                if (listenerContext.RequestHeaders.TryGetFirst("If-None-Match",out inm) && !string.IsNullOrEmpty (inm) && inm == etag) {
                    listenerContext.StatusCode = 304;
                    listenerContext.WriteHeaders();
                    listenerContext.NetworkStream.Close();
                }
                else {
                    string content_type = "application/octet-stream";
                    listenerContext.StatusCode = 200;
                    listenerContext.ResponseHeaders.Add ("Etag", etag);
                    if (!string.IsNullOrEmpty (contentType))
                       content_type= contentType;
                    listenerContext.SendBytes(data,content_type);
                }
             
            }
        }

        class JsonHandler : RequestHandler
        {
            public const string ContentType = "application/json; charset=utf-8";

            readonly Func<UIContext, object> ctor;

            public JsonHandler (Func<UIContext, object> ctor)
            {
                this.ctor = ctor;
            }

            public static byte[] GetData (object obj)
            {
                var r = Ooui.JsonConvert.SerializeObject (obj);
                var e = new UTF8Encoding (false);
                return e.GetBytes (r);
            }

            public override void Respond (ServerContext listenerContext, UIContext context, CancellationToken token)
            {
               

                var data = GetData (ctor (context));

                listenerContext.StatusCode = 200;
                
                listenerContext.SendBytes(data,ContentType);
            }
        }

		class CustomHandler : RequestHandler
		{
			readonly Action<ServerContext, CancellationToken> responder;

			public CustomHandler (Action<ServerContext, CancellationToken> responder)
			{
				this.responder = responder;
			}

			public override void Respond (ServerContext listenerContext, UIContext context, CancellationToken token)
			{
				responder (listenerContext, token);
			}
		}

        void ProcessWebSocketRequest (ServerContext listenerContext, CancellationToken serverToken)
        {
           
            //
            // Find the element
            //
            var path = listenerContext.UrlPath;
            

            PublishedPath pp;
            var found = false;
            var variables = new Dictionary<string, string> ();

            lock (publishedPaths) found = publishedPaths.TryGetValue (path, out pp);
            if (!found) {
                List<PublishedPath> pps;
                lock (publishedPaths) pps = publishedPaths.Values.ToList ();
                foreach (var p in pps) {
                    var m = p.RegexPath.Match (path);
                    if (m.Success) {
                        pp = p;
                        found = true;
                        for (var ig = 1; ig < m.Groups.Count; ig++) {
                            variables[p.RegexPath.GroupNameFromNumber (ig)] = m.Groups[ig].Value;
                        }
                        break;
                    }
                }
            }

            var elementHandler = pp?.Handler as ElementHandler;
            if (!found || elementHandler == null) {
                listenerContext.StatusCode = 404;
                listenerContext.WriteHeaders();
                listenerContext.NetworkStream.Close();
                return;
            }

            Element element = null;
            bool disposeElementWhenDone = true;
            try {
                var context = UIContext.ForListenerContext (listenerContext, variables);
                context.QueryParams = listenerContext.QueryParams;
                element = elementHandler.GetElement (context);
                disposeElementWhenDone = elementHandler.DisposeElementWhenDone;

				if (element == null)
					throw new Exception ("Handler returned a null element");
            }
            catch (Exception ex) {
                listenerContext.StatusCode = 500;
                listenerContext.WriteHeaders();
                listenerContext.NetworkStream.Close();
                Error ("Failed to create element", ex);
                return;
            }

            //
            // Connect the web socket
            //
            //listenerContext.RequestHeaders.Add("Sec-WebSocket-Protocol","ooui");
            
          

            //
            // Set the element's dimensions
            //
            var query = listenerContext.QueryParams;
             if (!query.TryGetFirst ("w", out var wValue) || string.IsNullOrEmpty (wValue)) {
                wValue = "640";
            }
            if (!query.TryGetFirst ("h", out var hValue) || string.IsNullOrEmpty (hValue)) {
                hValue = "480";
            }
            var icult = System.Globalization.CultureInfo.InvariantCulture;
            if (!double.TryParse (wValue, System.Globalization.NumberStyles.Any, icult, out var w))
                w = 640;
            if (!double.TryParse (hValue, System.Globalization.NumberStyles.Any, icult, out var h))
                h = 480;

            //
            // Create a new session and let it handle everything from here
            //
            try {
                var session = new WebSocketSession (element, disposeElementWhenDone, w, h, Error, serverToken);
                listenerContext.StartWebSocketConnection(session.Opened,
                                                         session.Arrived,
                                                         session.Closed);            }
            
            catch (Exception ex) {
                Error ("Web socket failed", ex);
            }
            
        }

        void Error (string message, Exception ex)
        {
            if(!Verbose) return;
            Console.ForegroundColor = ConsoleColor.Red;

            Console.WriteLine ("{0}: {1}", message, ex);
            Console.ResetColor ();
        }

    
       


        static readonly Dictionary<string, Style> styles =
            new Dictionary<string, Style> ();
        static readonly StyleSelectors rules = new StyleSelectors ();

        public static StyleSelectors Styles => rules;

        public class StyleSelectors
        {
            public Style this[string selector] {
                get {
                    var key = selector ?? "";
                    lock (styles) {
                        if (!styles.TryGetValue (key, out Style r)) {
                            r = new Style ();
                            styles.Add (key, r);
                        }
                        return r;
                    }
                }
                set {
                    var key = selector ?? "";
                    lock (styles) {
                        if (value == null) {
                            styles.Remove (key);
                        }
                        else {
                            styles[key] = value;
                        }
                    }
                }
            }

            public void Clear ()
            {
                lock (styles) {
                    styles.Clear ();
                }
            }

            public override string ToString()
            {
                lock (styles) {
                    var q =
                        from s in styles
                        let v = s.Value.ToString ()
                        where v.Length > 0
                        select s.Key + " {" + s.Value.ToString () + "}";
                    return String.Join ("\n", q);
                }
            }
        }
    }

    public class UIContext
    {
        public Dictionary<string,List<string>> QueryParams {get;set;}=new Dictionary<string, List<string>>();
        readonly Dictionary<string, string> variables = new Dictionary<string, string> ();

        public string RequestUrl { get; }

        public string this[string key] => variables.TryGetValue (key, out var v) ? v : "";

        public UIContext (string requestUrl)
        {
            RequestUrl = requestUrl ?? throw new ArgumentNullException (nameof (requestUrl));
        }

        public static UIContext ForListenerContext (ServerContext listenerContext, Dictionary<string, string> variables)
        {
            var c = new UIContext (listenerContext.UrlPath);
            foreach (var kv in variables) {
                c.variables.Add (kv.Key, kv.Value);
            }
            return c;
        }

        public static UIContext ForWebAssemblySession (string sessionId, string elementPath)
        {
            throw new NotSupportedException("Not supported on this fork");
        }
    }
}