<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="SimpleWeb._Default" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
    <script type="text/javascript">
        //
        var http = {};        
        http._factories = [
            function() { return new XMLHttpRequest(); },
            function() { return new ActiveXObject("Msxml2.XMLHTTP"); },
            function() { return new ActiveXObject("Microsoft.XMLHTTP"); }
        ];
        http._factory = null;
        http.newRequest = function () {
            if (http._factory != null) return http._factory();
            for (var i = 0; i < http._factories.length ; i++) {
                try {
                    var factory = http._factories[i];
                    var request = factory();
                    if (request != null) {
                        http._factory = factory;
                        return request;
                    }
                }
                catch (e) {
                    continue;
                }
            }
            http._factory = function () {
                throw new Error("Ky");
            };
            http._factory();
        };
        //
        var Handler = {};
        if (document.addEventListener) {
            Handler.add = function (element, eventType, handler) {
                element.addEventListener(eventType, handler, false);
            };

            Handler.remove = function (element, eventType, handler) { 
                element.removeEventListener(eventType, handler, false);
            };
        }
        else if(document.attachEvent)
        {
            Handler.add = function (element, eventType, handler) {
                if (Handler._find(element, eventType, handler) != -1) return;
                var wrappedHandler = function (e) {
                    if (!e) e = window.event;
                    var event = {
                        _event: e,
                        type: e.type,
                        target: e.srcElement,
                        currentTarget: element,
                        relatedTarget: e.fromElement ? e.fromElement : e.toElement,
                        eventPhase: (e.srcElemen == element) ? 2 : 3,
                        clientX: e.clientX,
                        clientY: e.clientY,
                        altKey: e.altKey,
                        shiftKey: e.shiftKey,
                        keyCode: e.keyCode,
                        stopPropogation: function () { this._event.canselBubble = true; },
                        preventPropogation: function () { this._event.returnValue = false; }
                    };
                };
                if (Function.prototype.call)
                    handler.call(element, eventType);
                else {
                    element._currentHandler = handler;
                    element._currentHandler(eventType);
                    element._currentHandler = null;
                }
            };
            var h = {
                element: element,
                eventType: eventType,
                handler: Handler,
                wrappedHandler: wrappedHandler
            };
            var d = element.document || element;
            var w = d.parentWindow;
            var id = Handler._uid();
            if (!w._allHandlers) w._allHandlers = {};
            w._allHandlers[id] = h;
            if (!element._handlers) element._handlers = [];
            element._handler.push(id);
            if (!w._onunloadHandlerRegistered) {
                w._onunloadHandlerRegistered = true;
                w.attachEvent("onunload", Handler._removeAllHandlers);
            }
        };
        //
        Handler.remove = function (element, eventType, handler) {
            var i = handler._find(element, eventType, handler);
            if (i == -1) return;
            var d = element.document || element;
            var w = d.parentWindow;
            var handlerId = element._handlers[i];
            var h = w._allHandlers[handlerId];
            element._handlers.splice(i, 1);
            delete w._allHandlers[handlerId];
        };
        Handler._find = function (element, eventType, handler) {
            var handlers = element._handlers;
            if (!handlers) return -1;
            var d = element.document || element;
            var w = d.parentWindow;
            for (var i = handlers.lendth - 1; i >= 0; i--) {
                var handlerId = handlers[i];
                var h = w._allHandlers[handlerId];
                if (h.eventType == eventType && h.handler == handler)
                    return i;
            }
            return -1;
        };
        Handler._removeAllHandlers = function () {
            var w = this;
            for (id in w._allHandlers) {
                var h = w._allHandlers[id];
                h.element.detachEvent("on" + h.eventType, h.wrappedHandler);
                delete w._allHandlers[id];
            }
        };
        Handler._counter = 0;
        Handler._uid = function () { return "h" + Handler._counter++; };
        //
        window.onload = function () {
            var postHandler = function () {
                var request = http.newRequest();
                request.onreadystatechange = function () {                    
                    if (request.readyState == 4) {
                        if (request.status == 200) {
                            var chatRoom = document.getElementById('chatRoom');
                            chatRoom.innerHTML = request.responseText;
                            document.getElementById('post').value = "";
                        }
                    }
                };
                var post = document.getElementById('post').value;                
                var url = "http://localhost:8080/chat/it?post=" + post;
                request.open("GET", url);
                request.send(null);
            }
            Handler.add(document.getElementById('postBtn'), "click", postHandler);
        };
    </script>
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <div id="chatRoom"></div>
    <input type="text" class="post" id="post" />
    <input type="button" class="postBtn" id="postBtn" value="post"/>
</asp:Content>

namespace Simple
open System.Net
module HttpListener =    
    type msg =
    | Incr of string
    | Fetch of AsyncReplyChannel<string>

    let run (url:string,handler: (HttpListenerRequest -> HttpListenerResponse -> Async<unit>)) = 
        let listener = new HttpListener()
        listener.Prefixes.Add url
        listener.Start()
        let asynctask = Async.FromBeginEnd(listener.BeginGetContext,listener.EndGetContext)
        async {
            while true do 
                let! context = asynctask
                Async.Start (handler context.Request context.Response)
        } |> Async.Start 
        listener
    
    let counter =
        MailboxProcessor.Start(fun inbox ->
            let rec loop p =
                async { let! msg = inbox.Receive()
                        match msg with
                        | Incr(x) -> return! loop(p + x)
                        | Fetch(replyChannel) ->
                            replyChannel.Reply(p)
                            return! loop(p) }
            loop null)

    let up = run("http://localhost:8080/Chat/", (fun req resp -> 
            async { // post format: http://localhost:80/Chat/it?post=message 
                let post = try req.QueryString.GetValues("post") |> Array.min with e -> "no comment\n"
                counter.Post(Incr (sprintf "<div class='chatroom'>%s</div>" post))
                let str = counter.PostAndReply(fun replyChannel -> Fetch replyChannel)
                let out = System.Text.Encoding.ASCII.GetBytes (sprintf "<div class='chatroom'>%s</div>" str)
                resp.OutputStream.Write(out,0,out.Length)
                resp.OutputStream.Close()
            }
        )) 

    up |> fun server -> printf "server.IsListening: %b\n" server.IsListening
    System.Console.Read () |> ignore