using System;
using System.Web;
using System.Web.Mvc;

namespace Kreta.Web.Security
{
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
    public class MvcFeatureAuthorizeAttribute : AuthorizeAttribute
    {
        private readonly string[] featureNames;

        public MvcFeatureAuthorizeAttribute(params string[] features)
        {
            featureNames = features;
        }

        public override void OnAuthorization(AuthorizationContext filterContext)
        {
            if (AuthorizeCore(filterContext.HttpContext))
            {
                HttpCachePolicyBase cache = filterContext.HttpContext.Response.Cache;
                cache.SetProxyMaxAge(new TimeSpan(0L));
                cache.AddValidationCallback(new HttpCacheValidateHandler(CacheValidateHandler), null);
            }
            else
            {
                HandleUnauthorizedRequest(filterContext);
            }
        }

        protected override bool AuthorizeCore(HttpContextBase httpContext)
        {
            return AuthorizeHelper.CheckFeatureAccess(featureNames);
        }

        protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
        {
            AuthorizeHelper.MvcRequestAuthorizeFail(filterContext);
        }

        protected override HttpValidationStatus OnCacheAuthorization(HttpContextBase httpContext)
        {
            return !AuthorizeCore(httpContext) ? HttpValidationStatus.IgnoreThisRequest : HttpValidationStatus.Valid;
        }

        private void CacheValidateHandler(HttpContext context, object data, ref HttpValidationStatus validationStatus)
        {
            validationStatus = OnCacheAuthorization(new HttpContextWrapper(context));
        }
    }
}