using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Oqtane.Enums;
using Oqtane.Extensions;
using Oqtane.Infrastructure;
using Oqtane.Models;
using Oqtane.Repository;
using Oqtane.Security;
using Oqtane.Shared;
using SZUAbsolventenverein.Module.EventRegistration.Models;
using SZUAbsolventenverein.Module.EventRegistration.Repository;

namespace SZUAbsolventenverein.Module.EventRegistration.Services
{
    public class ServerEventRegistrationService : IEventRegistrationService
    {
        private readonly IEventRepository _EventRepository;
        private readonly IResponseRepository _ResponseRepository;
        private readonly INotificationRepository _NotificationRepository;
        private readonly IUserRepository _UserRepository;
        private readonly IUserPermissions _userPermissions;
        private readonly ILogManager _logger;
        private readonly IHttpContextAccessor _accessor;
        private readonly ISettingRepository _settingRepository;
        private readonly Alias _alias;

        public ServerEventRegistrationService(IEventRepository EventRepository, IResponseRepository ResponseRepository, INotificationRepository NotificationRepository, IUserRepository UserRepository, IUserPermissions userPermissions, ITenantManager tenantManager, ILogManager logger, IHttpContextAccessor accessor, ISettingRepository settingRepository)
        {
            _EventRepository = EventRepository;
            _ResponseRepository = ResponseRepository;
            _NotificationRepository = NotificationRepository;
            _UserRepository = UserRepository;
            _userPermissions = userPermissions;
            _logger = logger;
            _accessor = accessor;
            _settingRepository = settingRepository;
            _alias = tenantManager.GetAlias();
        }

        public Task<Event> AddEventAsync(Event NewEvent)
        {
            if (_userPermissions.IsAuthorized(_accessor.HttpContext.User, _alias.SiteId, EntityNames.Module, NewEvent.ModuleId, PermissionNames.Edit))
            {
                NewEvent = _EventRepository.AddEvent(NewEvent);
                _logger.Log(LogLevel.Information, this, LogFunction.Create, "EventRegistration Added {NewEvent}", NewEvent);
            }
            else
            {
                _logger.Log(LogLevel.Error, this, LogFunction.Security, "Unauthorized EventRegistration Add Attempt {NewEvent}", NewEvent);
                NewEvent = null;
            }
            return Task.FromResult(NewEvent);
        }

        public Task<Response> AddResponseAsync(Response Response)
        {
            if (_userPermissions.IsAuthorized(_accessor.HttpContext.User, _alias.SiteId, EntityNames.Module, Response.ModuleId, PermissionNames.View))
            {
                Response = _ResponseRepository.AddResponse(Response);

                Event currentEvent = _EventRepository.GetEvent(Response.EventRegistrationId);
                string subject = Response.ResponseType ? $"Du bist erfolgreich für '{currentEvent.Name}' Registriert worden." : $"Du hast erfolgreich für '{currentEvent.Name}' abgesagt.";
                string body = "Hier kann man die Infos des Events hineinpacken (HTML ist erlaubt)";
                SendEventResponseNotification(subject, body);

                _logger.Log(LogLevel.Information, this, LogFunction.Create, "EventRegistration Added {NewEvent}", Response);
            }
            else
            {
                _logger.Log(LogLevel.Error, this, LogFunction.Security, "Unauthorized EventRegistration Add Attempt {NewEvent}", Response);
                Response = null;
            }
            return Task.FromResult(Response);
        }

        public Task<Response> UpdateResponseAsync(Response Response)
        {

            if (_userPermissions.IsAuthorized(_accessor.HttpContext.User, _alias.SiteId, EntityNames.Module, Response.ModuleId, PermissionNames.View))
            {
                Response = _ResponseRepository.UpdateResponse(Response);

                Event currentEvent = _EventRepository.GetEvent(Response.EventRegistrationId);
                string subject = Response.ResponseType ? $"Du bist erfolgreich für '{currentEvent.Name}' registriert." : $"Du hast erfolgreich für '{currentEvent.Name}' abgesagt.";
                string body = currentEvent.Description;
                SendEventResponseNotification(subject, body);
                
                _logger.Log(LogLevel.Information, this, LogFunction.Create, "EventRegistration Added {NewEvent}", Response);
            }
            else
            {
                _logger.Log(LogLevel.Error, this, LogFunction.Security, "Unauthorized EventRegistration Add Attempt {NewEvent}", Response);
                Response = null;
            }
            return Task.FromResult(Response);
        }

        public Task DeleteEventAsync(int EventId, int ModuleId)
        {
            if (_userPermissions.IsAuthorized(_accessor.HttpContext.User, _alias.SiteId, EntityNames.Module, ModuleId, PermissionNames.Edit))
            {
                _EventRepository.DeleteEvent(EventId);
                _logger.Log(LogLevel.Information, this, LogFunction.Delete, "Event Deleted {EventId}", EventId);
            }
            else
            {
                _logger.Log(LogLevel.Error, this, LogFunction.Security, "Unauthorized Event Delete Attempt {EventId} {ModuleId}", EventId, ModuleId);
            }
            return Task.CompletedTask;
        }

        public Task<Event> GetEventAsync(int EventId, int ModuleId)
        {
            if (_userPermissions.IsAuthorized(_accessor.HttpContext.User, _alias.SiteId, EntityNames.Module, ModuleId, PermissionNames.View))
            {
                return Task.FromResult(_EventRepository.GetEvent(EventId, true));
            }
            else
            {
                _logger.Log(LogLevel.Error, this, LogFunction.Security, "Unauthorized Event Get Attempt {ModuleId}", ModuleId);
                return null;
            }
        }

        public Task<(Event, Response)> GetEventDetails(int EventId, int ModuleId)
        {
            if (_userPermissions.IsAuthorized(_accessor.HttpContext.User, _alias.SiteId, EntityNames.Module, ModuleId, PermissionNames.View))
            {
                Event currentEvent = _EventRepository.GetEvent(EventId);
                Response rsvp = _ResponseRepository.GetResponse(EventId, _accessor.HttpContext.User.UserId());
                return Task.FromResult((currentEvent, rsvp));
            }
            else
            {
                _logger.Log(LogLevel.Error, this, LogFunction.Security, "Unauthorized Event Get Attempt {ModuleId}", ModuleId);
                return null;
            }
        }

        public Task<List<Response>> GetEventResponses(int EventId, int ModuleId)
        {
            if (_userPermissions.IsAuthorized(_accessor.HttpContext.User, _alias.SiteId, EntityNames.Module, ModuleId, PermissionNames.Edit))
            {
                return Task.FromResult(_ResponseRepository.GetResponses(EventId, ModuleId).ToList());
            }
            else
            {
                _logger.Log(LogLevel.Error, this, LogFunction.Security, "Unauthorized Event Response Get Attempt {ModuleId}", ModuleId);
                return null;
            }
        }

        public async Task<List<User>> GetRecommendedResponses(int EventId, int ModuleId)
        {
            if (_userPermissions.IsAuthorized(_accessor.HttpContext.User, _alias.SiteId, EntityNames.Module, ModuleId, PermissionNames.View))
            {
                IEnumerable<Response> responses = _ResponseRepository.GetResponses(EventId, ModuleId).DistinctBy(r => r.OwnerId).Where(r => r.OwnerId != _accessor.HttpContext.User.UserId() && r.ResponseType);
                IEnumerable<User> users = _UserRepository.GetUsers();
                
                List<Setting> userSettings = _settingRepository.GetSettings("User").ToList();
                
                List<Setting> requestorSettings = userSettings.FindAll(s => s.EntityId == _accessor.HttpContext.User.UserId());
                string targetFachrichtung = requestorSettings.FirstOrDefault(s => s.SettingName == "Fachrichtung")?.SettingValue;
                int targetStartjahr = int.Parse(requestorSettings.FirstOrDefault(s => s.SettingName == "Jahrgang")?.SettingValue ?? "0");


                IEnumerable<GroupingUser> gu = responses.Join(users, r => r.OwnerId, u => u.UserId,
                    (response, user) => (response, user)).GroupJoin(userSettings, ru => ru.user.UserId,
                    s => s.EntityId, (ru, s) => new GroupingUser(ru.user, ru.response, s, targetStartjahr, targetFachrichtung)).OrderBy(gu => gu.Score());
                return gu.Select(gu => gu.User).Take(10).ToList();
            }
            else
            {
                _logger.Log(LogLevel.Error, this, LogFunction.Security, "Unauthorized Event Response Get Attempt {ModuleId}", ModuleId);
                return null;
            }
        }

        public Task<List<Event>> GetEventsAsync(int ModuleId)
        {
            if (_userPermissions.IsAuthorized(_accessor.HttpContext.User, _alias.SiteId, EntityNames.Module, ModuleId, PermissionNames.View))
            {
                return Task.FromResult(_EventRepository.GetEvents(ModuleId).ToList());
            }
            else
            {
                _logger.Log(LogLevel.Error, this, LogFunction.Security, "Unauthorized Events Get Attempt {ModuleId}", ModuleId);
                return null;
            }
        }

        public Task<Event> UpdateEventAsync(Event NewEvent)
        {
            if (_userPermissions.IsAuthorized(_accessor.HttpContext.User, _alias.SiteId, EntityNames.Module, NewEvent.ModuleId, PermissionNames.Edit))
            {
                NewEvent = _EventRepository.UpdateEvent(NewEvent);
                _logger.Log(LogLevel.Information, this, LogFunction.Update, "Event Updated {NewEvent}", NewEvent);
            }
            else
            {
                _logger.Log(LogLevel.Error, this, LogFunction.Security, "Unauthorized Event Update Attempt {NewEvent}", NewEvent);
                NewEvent = null;
            }
            return Task.FromResult(NewEvent);
        }

        private void SendEventResponseNotification(string subject, string body)
        {
            User user = _UserRepository.GetUser(_accessor.HttpContext.User.UserId());
            Notification notification = new Notification(_alias.SiteId, user, subject, body);
            _NotificationRepository.AddNotification(notification);
        }
    }

    public class GroupingUser
    {
        private User _user;
        private Response _response;
        
        private string _fachrichtung;
        private int _startjahr;

        private int _targetyear;
        private string _targetfachrichtung;
        public User User { get { return _user; } }

        public IEnumerable<Setting> Settings
        {
            set
            {
                if (value == null)
                {
                    _fachrichtung = "-";
                    _startjahr = 0;
                    return;
                }
                _fachrichtung = value.FirstOrDefault(v => v.SettingName == "Fachrichtung", new Setting(){SettingValue = "-"}).SettingValue;
                _startjahr = int.Parse(value.FirstOrDefault(v => v.SettingName == "Jahrgang", new Setting(){SettingValue = "0"}).SettingValue);
            }
        }
        
        public string TargetFachrichtung
        {
            set { _targetfachrichtung = value; }
        }
        public int TargetJahr
        {
            set { _targetyear = value; }
        }

        public GroupingUser(User user, Response response, IEnumerable<Setting> settings, int targetyear, string targetfachrichtung)
        {
            _user = user;
            _response = response;
            Settings = settings;
            TargetJahr = targetyear;
            TargetFachrichtung = targetfachrichtung;
        }

        public int Score()
        {
            int total = 0;
            total += ScoreYear() * 5;
            total += ScoreFachrichtung() * 3;

            return total;
        }
        
        private int ScoreYear()
        {
            return Math.Abs(_targetyear - _startjahr);
        }

        private int ScoreFachrichtung()
        {
            if (_fachrichtung == _targetfachrichtung)
            {
                return 1;
            }
            else
            {
                return 0;
            }
        }
    }
}