using System;
using System.Linq;
using System.Net;
using System.Reflection;
using System.Security;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.ServiceModel.Dispatcher;
using System.Xml;

using BeWo.Data;
using BeWo.Data.Access;
using BeWo.Data.Entities;
using BeWo.Service.Core;
using BeWo.Service.ServiceUtils;
using BS.Shared.Attributes;
using BS.Shared.Extensions;
using NHibernate.Hql.Ast.ANTLR.Tree;

namespace BeWo.Service.Security
{
	public class SecurityContextInitializer : ICallContextInitializer
	{
		private readonly string[] ALLOW_ALWAYS = new string[]
		{
			//"Download",
			//"Download2",
			//"DownloadInfo",
			//"GetUpdatePlan",
			//"GetUpdateFile",
			"ResetAllTenants",
			"IsUserValid",
			"IsUserValidTwoFactor",
			"ResetTenant",
			"GetEmailForUserName",
			"GetTranslationDictionary",
		};

		private readonly string[] ALLOW_ONLY_WITH_LOGIN = new string[] {
			"LoadUserByNameAndPassword",
			"LoadUserByLoginName",
			"GetMandator",
			"LoadEmployee",
			"GetPersonsHavingBirthday",
			"GetLastLogins",
			"GetSupportConceptsWithConferenceDate",
			"GetExpiringSupportConcepts",
			"GetPublishedNewsItemsForEmployee",
			"GetAllActiveEmployeesCompact",
			"GetHomeViewPanels",
			"LoadCompactEmployee",
			"GetTranslationDictionary",
			"ConvertToNewSubstitutionType" };

		public void AfterInvoke(object pCorrelationState)
		{
			if (pCorrelationState is LoggedInUserOperationContextExt)
			{
				OperationContext.Current.Extensions.Remove((LoggedInUserOperationContextExt)pCorrelationState);
			}
		}

		public object BeforeInvoke(InstanceContext pInstanceContext, IClientChannel pChannel, Message pMessage)
		{
			try
			{
				ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

				var lTemp = pMessage.Headers.Action.Split("/");
				string lMethodName = lTemp[lTemp.Count - 1];
				string lServiceInterface = lTemp[lTemp.Count - 2];

				// TODO Hier kann man jetzt etwas bauen wer sich für welchen service autorisieren muss...
				if (ALLOW_ALWAYS.Contains(lMethodName))
				{
					return null;
				}
				else
				{
					// Vergessen neue Methode einzutragen?
				}

				string lUserName = null, lPassword = null;

				int lSecurityHeaderIndex = pMessage.Headers.FindHeader("Security", "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd");

				if (lSecurityHeaderIndex > -1)
				{
					XmlReader lReader = pMessage.Headers.GetReaderAtHeader(lSecurityHeaderIndex);

					if (lReader.ReadToFollowing("Username"))
					{
						lUserName = lReader.ReadString();
					}

					if (lReader.ReadToFollowing("Password"))
					{
						lPassword = lReader.ReadString();
					}

					ApplicationUser lUser = DAOFactory.UserDAO.FindUserByLoginName(lUserName);

					if (lUser != null && DAOFactory.UserDAO.CheckPassword(lUser, lPassword))
					{
						if (!HasMethodAuthorization(lUser, lMethodName, pMessage))
						{
							throw new SecurityException("Methode nicht autorisiert: " + lMethodName);
						}

						var lExt = new LoggedInUserOperationContextExt { User = lUser, LoginName = lUserName, UnhashedPassword = lPassword };
						OperationContext.Current.Extensions.Add(lExt);
						return lExt;
					}
				}

				throw new SecurityException("Nicht autorisiert");
			}
			catch (Exception e)
			{
				throw Utils.CreateBeWoFaultException(e);
			}
		}

		private bool HasMethodAuthorization(ApplicationUser pUser, string methodName, Message pMessage)
		{
			if (ALLOW_ONLY_WITH_LOGIN.Contains(methodName))
			{
				return true;
			}
			else
			{
				// Vergessen neue Methode einzutragen?
			}

			var rights = Utils.GetGrantedRights(pUser);

			// Finde Action
			var lTemp = pMessage.Headers.Action?.Split("/");

			if (lTemp is null)
				lTemp = pMessage.Headers.To.Segments.ToList();

			if (lTemp is null)
				throw new ArgumentException("Kann Action nicht finden");

			// Extrahiere MethodeName + ServiceInterface
			string lMethodName = lTemp[lTemp.Count - 1].Trim('/');
			string lServiceInterface = lTemp[lTemp.Count - 2].Trim('/');

			try
			{
				var attribute = ServiceHelper.GetCustomAttribute<RequirePermissionAttribute>(lServiceInterface, lMethodName);
				if (attribute != null)
				{
					return attribute.HasPermission(rights);
				}
			}
			catch (Exception e)
			{

			}

			return true;
		}

	}
}