using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.Net.Http.Headers;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
using Sarand.Net.Standard.Base.App;
using Sarand.Net.Standard.Base.Bus;
using Sarand.Net.Standard.Base.Dbas;
using Sarand.Net.Standard.Base.Helpers;
using Sarand.Net.Standard.Base.Utils;
using Saxonite.Net.Core.Web.Base.App;
using Saxonite.Net.Core.Web.Base.Models;
using Saxonite.Net.Standard.Base.App;
using Saxonite.Net.Standard.Base.Consoles;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;

namespace Saxonite.Net.Core.Web.Base.Controllers
{
	//=======================================================================
	public abstract class SaxController_Web : SaxController_Base
	{
		//-------------------------------------------------------------------
		// Data members.

		//-------------------------------------------------------------------
		// Protected construction.
		protected SaxController_Web(SaxLocaliser localiser) : base(localiser)
		{
		}
		protected override void Dispose(bool disposing)
		{
			if (disposing)
			{
			}
			base.Dispose(disposing);
		}

		//-------------------------------------------------------------------
		// Properties.

		//-------------------------------------------------------------------
		// Action execution events.
		//-------------------------------------------------------------------
		public override void OnActionExecuting(ActionExecutingContext filterContext)
		{
			//if (DebugMode) SaLogger.Debug($"{SysUtil.Fn}" + (ViewData.Model != null ? " Model: " + ViewData.Model : ""));

			// Refreh model properties.
			SaxModel_Base baseModel = ViewData.Model as SaxModel_Base;
			RefreshModel(baseModel);

			base.OnActionExecuting(filterContext);
		}
		public override void OnActionExecuted(ActionExecutedContext filterContext)
		{
			//if (DebugMode) SaLogger.Debug($"{SysUtil.Fn}" + (ViewData.Model != null ? " Model: " + ViewData.Model : ""));

			// Refreh model properties.
			SaxModel_Base baseModel = ViewData.Model as SaxModel_Base;
			RefreshModel(baseModel);

			// Store session data if present - as potentially modfied.
			if (SessionData != null)
			{
				// Most actions will store the session data in case it's been modified.
				// Some actions (eg. score password) don't need to.
				if (StoreSessionData)
				{
					String sessionDataJson = JsonConvert.SerializeObject(SessionData);
					HttpContext.Session.Set(SessionStorage.SessionKey_SessionData, SessionStorage.sessionDataEncoding.GetBytes(sessionDataJson));
				}
			}
			else HttpContext.Session.Remove(SessionStorage.SessionKey_SessionData);

			// Response headers.
			if (baseModel != null && baseModel.ProhibitCache)
			{
				if (Response.Headers.ContainsKey(HeaderNames.CacheControl))
					Response.Headers.Remove(HeaderNames.CacheControl);
				Response.Headers.Add(HeaderNames.CacheControl, "no-cache, no-store, must-revalidate");
				Response.Headers.Add(HeaderNames.Pragma, "no-cache");
				Response.Headers.Add(HeaderNames.Expires, "0");
			}

			base.OnActionExecuted(filterContext);
		}

		//-------------------------------------------------------------------
		// Model.
		//-------------------------------------------------------------------
		protected void RefreshModel(SaxModel_Base model)
		{
			if (model == null) return;

			// Session data.
			model.Controller = this;
			model.SessionData = SessionData;

			// Redirect locations.
			model.RedirectLocation.Base = GetRedirectLocation(RedirectLocation.WebAppBase);
			model.RedirectLocation.Home = GetRedirectLocation(RedirectLocation.WebAppHome);
			model.RedirectLocation.Home_SessionExpired = GetRedirectLocation(RedirectLocation.WebAppHome_SessionExpired);
		}

		//-------------------------------------------------------------------
		// Parameters.
		//-------------------------------------------------------------------
		// Online Request Password encryption parameters (key & IV) are defined in
		// the base Controller so that they can be shared with the Adnin application.
		// NB IV value is generated from the key and fixed so that it doesn't change when the application restarts.
		// IV Must be regenerated if key is changed.
		protected static String Base64Key_RequestPassword_Online { get; } = SacsEncryptionHelper.EncodePlainKey("{~Saxonite@@Request^Password=}", SacsEncryptionHelper.KeyLength);
		//private static String Base64IV_RequestPassword_Generated_Online { get; } = SacsEncryptionHelper.InitSymmetricEncryptionIV(Base64Key_RequestPassword_Online);
		protected static String Base64IV_RequestPassword_Online { get; } = "1VAWYTW6d72n/6HDNhbqow==";

		//-------------------------------------------------------------------
		// Session.
		//-------------------------------------------------------------------
		private bool UserActiveRecorded { get; set; } = false;
		public bool ValidUserSession
		{
			get
			{
				if (SessionData == null || !SessionData.ValidUserSession) return false;
				SaxSessionDataConsole sessionDataConsole = SessionDataConsole;
				if (sessionDataConsole != null && !UserActiveRecorded)
				{
					// Record the user as active once per request.
					sessionDataConsole.RecordUserActive(SessionUserAccountId, CreatedAt);
					UserActiveRecorded = true;
				}
				return true;
			}
		}
		public SysId SessionUserAccountId { get { return SessionData?.User?.UserAccountId ?? null; } }
		public DbUpdateInfo DbUpdateInfo { get { return SessionData?.DbUpdateInfo ?? new DbUpdateInfo(null, "", SaxSystem.ComputerName); } }
		// Referrer.
		public String Referer { get { return Request.Headers["Referer"].ToString(); } }
		public bool ValidReferer { get { return !StringUtil.IsEmpty(Referer); } }

		/// <summary>Store session data, eg. to start a new user session on sign-in.</summary>
		protected bool SetSessionData(SaxSessionData sessionData)
		{
			if (sessionStorage.SessionData != null) return false;
			sessionStorage.SessionData = sessionData;
			return true;
		}
		protected void ClearSessionData()
		{
			if (HttpContext.Session.IsAvailable)
				HttpContext.Session.Clear();
			sessionStorage.SessionData = null;
		}

		//-------------------------------------------------------------------
		// Session storage.
		public class SessionStorage
		{
			public SaxSessionData SessionData { get; set; }
			public static String SessionKey_SessionData { get; } = "SaxSessionData";
			public static Encoding sessionDataEncoding { get; } = Encoding.UTF8;
			//JSON Serialisation.
			public class SaxSessionDataContractResolver : DefaultContractResolver
			{
				// To allow private properties to be deserialised.
				// NB Only applies to top level properties in the serialised object.
				protected override List<MemberInfo> GetSerializableMembers(Type objectType)
				{
					var flags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;
					MemberInfo[] fields = objectType.GetFields(flags);
					return fields
						.Concat(objectType.GetProperties(flags).Where(propInfo => propInfo.CanWrite))
						.ToList();
				}
				protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
				{
					return base.CreateProperties(type, MemberSerialization.Fields);
				}
			};
			public static JsonSerializerSettings JsonDeserialisationSettings = new JsonSerializerSettings
			{
				ContractResolver = new SaxSessionDataContractResolver(),
				// Force all deserialised objects to be replaced - to avoid proxy lists not populating.
				ObjectCreationHandling = ObjectCreationHandling.Replace
			};
		}
		private readonly SessionStorage sessionStorage = new SessionStorage();
		protected JsonSerializerSettings SaxSessionDataJsonSerializerSettings { get { return SessionStorage.JsonDeserialisationSettings; } }

		//-------------------------------------------------------------------
		public SaxSessionData SessionData
		{
			get
			{
				try
				{
					// Retrieve session data if not already in controller.
					if (sessionStorage.SessionData == null)
					{
						byte[] sessionDataBytes = null;
						HttpContext.Session.TryGetValue(SessionStorage.SessionKey_SessionData, out sessionDataBytes);
						if (sessionDataBytes != null)
						{
							String sessionDataJson = SessionStorage.sessionDataEncoding.GetString(sessionDataBytes);
							sessionStorage.SessionData = DeserializeSessionData(sessionDataJson);
						}
					}
					return sessionStorage.SessionData;
				}
				catch (Exception exc)
				{
					SaLogger.Warn($"{SysUtil.Fn} {exc.GetType().Name} - {exc.Message}{exc.GetStackEntries().Concat("", "\n\t")}");
				}
				return null;
			}
		}
		protected abstract SaxSessionData DeserializeSessionData(String sessionDataJson);

		//-------------------------------------------------------------------
	}
	//=======================================================================
}