using BeWo.Data;
using BeWo.Service.Attributes;
using BS.Shared;
using BS.Shared.DataContracts;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.Remoting.Channels;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.Text;
using System.Threading.Tasks;

namespace BeWo.Service.Core
{
	public static class ServiceValidator
	{
		public static void CheckSerializationError<T>(T data)
		{
			var serializer = new DataContractSerializer(typeof(T));
			using (var ms = new MemoryStream())
			{
				serializer.WriteObject(ms, data);
			}
		}

		public static bool TryCheckSerializationError<T>(T data)
		{
			try
			{
				CheckSerializationError(data);
			}
			catch (Exception ex)
			{
				File.WriteAllText("C:\\temp\\wcf-serialisierungsfehler.txt", ex.ToString());
				return false;
			}

			return true;
		}

		public static void ValidateConnection(ref Message request, IClientChannel channel)
		{
			var authentification = ServiceHelper.GetCustomAttribute<RequireApiAuthorizationAttribute>(request, channel);

			if (authentification is null)
				return;

			if (authentification.IPAddressList is IPAddressList ipAddressList && ipAddressList != IPAddressList.None)
				ValidateIP(ref request, channel, ipAddressList);

			if (authentification.ApiKeyName is WebSecretConfigSetting secret && secret != WebSecretConfigSetting.None)
				ValidateMethodApiKey(ref request, channel, secret);
		}

		public static object ValidateTenant(ref Message request, IClientChannel channel)
		{
			var authentification = ServiceHelper.GetCustomAttribute<RequireApiAuthorizationAttribute>(request, channel);

			if (authentification is object && authentification.IgnoreTenant)
				return null;

			string lTenant = null;

			// Hole tenant aus Header
			var prop = (HttpRequestMessageProperty)request.Properties[HttpRequestMessageProperty.Name];
			lTenant = prop?.Headers["tenant"];

			// Wenn kein Tenant gefunden wird, 
			if (string.IsNullOrWhiteSpace(lTenant))
			{
				throw new ArgumentException($"Zugriff verweigert. Tenant (\'{lTenant}\') darf nicht leer sein.", nameof(lTenant));
			}

			var lExt = new MultitenancyOperationContextExt { Tenant = lTenant };
			OperationContext.Current.Extensions.Add(lExt);
			return lExt;
		}

		private static void ValidateIP(ref Message request, IClientChannel channel, IPAddressList ipAddressList)
		{
			// Extrahiere die RemoteEndpoint-IP-Adresse
			string remoteIP = request.Properties.ContainsKey(RemoteEndpointMessageProperty.Name)
				? ((RemoteEndpointMessageProperty)request.Properties[RemoteEndpointMessageProperty.Name]).Address
				: null;

			if (remoteIP == null)
			{
				throw new UnauthorizedAccessException($"Zugriff verweigert. Remote IP (\"null\") ist nicht erlaubt.");
			}

			var allowedIPs = ConfigReader.GetIPAddressList(ipAddressList);

			if (allowedIPs is null || allowedIPs.Count == 0)
			{
				throw new UnauthorizedAccessException($"Zugriff verweigert. Konfigurationsfehler.");
			}

			if (allowedIPs.All(x => !string.Equals(remoteIP, x, StringComparison.OrdinalIgnoreCase)))
			{
				throw new UnauthorizedAccessException($"Zugriff verweigert. Remote IP ({remoteIP}) ist nicht erlaubt.");
			}
		}

		//public void ValidateServiceApiKey(ref Message request)
		//{
		//	//// Hole erlaubten API Key aus den appSettings
		//	//string allowedApikey = MergedConfig.GetSecretSetting(WebSecretConfigSetting.AdminServiceAPIKey);

		//	//// Extrahiert den API Key von Remote
		//	//var prop = (HttpRequestMessageProperty)request.Properties[HttpRequestMessageProperty.Name];
		//	//var remoteApikey = prop?.Headers["admin-service-api-key"];

		//	//// Vergleicht die API Keys
		//	//if (remoteApikey == null || !string.Equals(remoteApikey, allowedApikey, StringComparison.Ordinal))
		//	//{
		//	//	throw new UnauthorizedAccessException($"Zugriff verweigert. API Key ({remoteApikey ?? "Unbekannt"}) ist nicht erlaubt.");
		//	//}
		//}

		private static void ValidateMethodApiKey(ref Message request, IClientChannel channel, WebSecretConfigSetting secret)
		{
			// Hole erlaubten API Key aus den appSettings
			string allowedApikey = MergedConfig.GetSecretSetting(secret);

			if (string.IsNullOrEmpty(allowedApikey))
			{
				return;

				throw new UnauthorizedAccessException($"Zugriff verweigert. Api Key kann nicht geladen werden.");
			}

			// Extrahiert den API Key von Remote
			var prop = (HttpRequestMessageProperty)request.Properties[HttpRequestMessageProperty.Name];
			var remoteApikey = prop?.Headers[secret.ToString()];

			// Vergleicht die API Keys
			if (remoteApikey == null || !string.Equals(remoteApikey, allowedApikey, StringComparison.Ordinal))
			{
				throw new UnauthorizedAccessException($"Zugriff verweigert. API Key ({remoteApikey ?? "Unbekannt"}) ist nicht erlaubt.");
			}
		}
	}
}