using System;
using System.Text.RegularExpressions;
using System.Web;

namespace iPaper.Web.ArrCookieRestorer
{
    public class ArrCookieRestorer : IHttpModule
    {
        public void Dispose()
        { }

        public void Init(HttpApplication context)
        {
            context.BeginRequest += context_BeginRequest;
        }

        private void context_BeginRequest(object sender, EventArgs e)
        {
            try
            {
                HttpContext context = HttpContext.Current;
                string serverHash = context.Request.QueryString["ARRIPARRAffinity"];

                if (serverHash != null)
                {
                    string cookieHeader = context.Request.Headers["Cookie"];

                    if (cookieHeader != null)
                    {
                        if (cookieHeader.Contains("IPARRAffinity="))
                            cookieHeader = Regex.Replace(cookieHeader, "IPARRAffinity=[0-9a-f]+;?", "IPARRAffinity=" + serverHash + ";");
                        else
                            cookieHeader += "; IPARRAffinity=" + serverHash;

                        context.Request.Headers["Cookie"] = cookieHeader;
                    }
                    else
                        context.Request.Headers.Add("Cookie", "IPARRAffinity=" + serverHash);
                }
            }
            catch
            { }
        }
    }
}