using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;
using FLocal.Core;
using FLocal.Common;

namespace FLocal.IISHandler.handlers.request {
	abstract class AbstractPostHandler : ISpecificHandler {

		abstract protected string templateName {
			get;
		}

		virtual protected bool shouldBeLoggedIn {
			get {
				return true;
			}
		}

		virtual protected bool shouldBeGuest {
			get {
				return false;
			}
		}

		abstract protected XElement[] Do(WebContext context);

		protected IEnumerable<XElement> getCommonData(WebContext context) {
			return new XElement[] {
				new XElement("handlerName", this.GetType().FullName),
				new XElement("title", Config.instance.AppInfo),
				new XElement("timestamp", DateTime.Now.Ticks.ToString()),
				context.userSettings.skin.exportToXml(),
				context.exportSession(),
			};
		}

		private XDocument getData(WebContext context) {
			return new XDocument(
				new XElement("root",
					this.Do(context),
					this.getCommonData(context)
				)
			);
		}

		public void Handle(WebContext context) {

			try {
				Uri referer = context.httprequest.UrlReferrer;
				if(referer == null || referer.Host != context.httprequest.Url.Host) {
					throw new System.Web.HttpException(403, "Wrong referer");
				}

				if(this.shouldBeGuest && context.session != null) throw new FLocalException("Should be guest");
				if(this.shouldBeLoggedIn && context.session == null) throw new FLocalException("Should be anonymous");
				context.WriteTransformResult(this.templateName, this.getData(context));
			} catch(RedirectException) {
				throw;
			} catch(WrongUrlException) {
				throw;
			} catch(Exception e) {
				context.LogError(e);
				context.WriteTransformResult("Exception.xslt", new XDocument(new XElement("root", this.getCommonData(context), e.ToXml())));
			}
		}

	}
}