using System;
using System.Reflection;
using System.Web;
using GeneralApi.Core.Infrastructure.IoC;
using System.Web.UI;

namespace Taloyhtio.GeneralSSO.Server.CodeFiles.Infrastructure.Web
{
    public class InitializationModule : IHttpModule
    {
        private static bool initialized;
        private static readonly object lockObject = new object();

        public void Init(HttpApplication context)
        {
            context.BeginRequest += context_BeginRequest;
            // the following handler is needed for sending 401 status to jquery ajax when it is returned from dataapi.svc.
            // Without it ASP.Net will return 302 status and redirect url to the login page because forms based authentication is used.
            // See http://haacked.com/archive/2011/10/04/prevent-forms-authentication-login-page-redirect-when-you-donrsquot-want.aspx.
            context.EndRequest += OnEndRequest;
        }

        public void Dispose() {}

        private static void context_BeginRequest(object sender, EventArgs e)
        {
            // configuration is required only once per AppDomain
            if (!initialized)
            {
                lock (lockObject)
                {
                    if (!initialized)
                    {
                        IoCConfiguration.Configure();
                        log4net.Config.XmlConfigurator.Configure();
                        // DotNetOpenAuth uses the following call in order to determine whether log4net available or not:
                        // Assembly.Load("log4net");
                        // (see DotNetOpenAuth.Loggers.Log4NetLogger.IsLog4NetPresent). If it is not available it will
                        // use simple trace logger which logs records to trace output, which also can be problematic
                        // to read because it happens in IIS worker process (DebugView utility has problem with it).
                        // The problem that it fails when log4net is located in GAC. For fixing it we need to attach own
                        // handler for AppDomain.AssemblyResolve event and resolve it by full name
                        AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;
                        initialized = true;
                    }
                }
            }

            // with CORS jquery.ajax() first sends OPTIONS request to endpoint and asks
            // whether appropriate origin (caller), verb and headers are allowed.
            // We need to answer on it with appropriate values.
            if (HttpContext.Current.Request.RawUrl.ToLower().Contains("dataapi.svc"))
            {
                HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "*");
                HttpContext.Current.Response.AddHeader("Access-Control-Expose-Headers", "WWW-Authenticate");

                if (HttpContext.Current.Request.HttpMethod == "OPTIONS")
                {
                    HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "POST,GET,PUT,DELETE,OPTIONS");
                    HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "Authorization, Content-Type");
                    HttpContext.Current.Response.AddHeader("Access-Control-Max-Age", "120");
                    HttpContext.Current.Response.End();
                }
            }

            //if (HttpContext.Current.Request.RawUrl.ToLower().Contains("/pages/root.aspx"))
            //{
            //    Page page = HttpContext.Current.CurrentHandler as Page;
            //    page.MasterPageFile = "/_catalogs/taloyhtio_custom_layout.master";
            //}
        }

        private static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
        {
            if (args.Name == "log4net")
            {
                return Assembly.Load("log4net, Version=1.2.11.0, Culture=neutral, PublicKeyToken=669e0ddf0bb1aa2a");
            }
            return null;
        }

        private void OnEndRequest(object source, EventArgs args)
        {
            var context = (HttpApplication)source;
            var response = context.Response;
            var request = context.Request;

            string contentType = request.Headers["Content-Type"];
            if (contentType != null && contentType.ToLower().Contains("application/json") && response.StatusCode == 302)
            {
                response.TrySkipIisCustomErrors = true;
                response.ClearContent();
                response.StatusCode = 401;
                response.RedirectLocation = null;
            }
        }
    }
}