#nullable enable
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;

namespace gehGassi.Web.Hubs
{
    /// <summary>
    /// Hub der Systemnachrichten ermöglicht
    /// </summary>
    [Authorize]
    public class SystemHub : Hub, ISystemHub
    {
        private readonly IHubContext<SystemHub> _hubContext;
        private readonly ISystemHubUsers _systemHubUsers;

        /// <summary>
        /// Erstellt eine Instanz
        /// </summary>
        public SystemHub(IHubContext<SystemHub> hubContext, ISystemHubUsers systemHubUsers) : base()
        {
            _hubContext = hubContext;
            _systemHubUsers = systemHubUsers;
        }

        #region Benutzer

        /// <summary>
        /// Called when a new connection is established with the hub.
        /// </summary>
        /// <returns>A <see cref="T:System.Threading.Tasks.Task" /> that represents the asynchronous connect.</returns>
        public override Task OnConnectedAsync()
        {
            if (Context.User?.Identity != null)
            {
                var userName = Context.User.Identity.Name;
                _systemHubUsers.ConnectedUsers.TryGetValue(userName, out var existingUserConnectionIds);
                existingUserConnectionIds ??= new List<string>();
                existingUserConnectionIds.Add(Context.ConnectionId);
                _systemHubUsers.ConnectedUsers.TryAdd(userName, existingUserConnectionIds);
            }

            return base.OnConnectedAsync();
        }

        /// <summary>Called when a connection with the hub is terminated.</summary>
        /// <returns>A <see cref="T:System.Threading.Tasks.Task" /> that represents the asynchronous disconnect.</returns>
        public override Task OnDisconnectedAsync(Exception? exception)
        {
            if (Context.User?.Identity != null)
            {
                var userName = Context.User.Identity.Name;
                _systemHubUsers.ConnectedUsers.TryGetValue(userName, out var existingUserConnectionIds);
                existingUserConnectionIds?.Remove(Context.ConnectionId);
                if (existingUserConnectionIds != null && existingUserConnectionIds.Count == 0)
                {
                    _systemHubUsers.ConnectedUsers.TryRemove(userName, out var garbage);
                }
            }

            return base.OnDisconnectedAsync(exception);
        }

        #endregion


        /// <summary>
        /// Buchen der Events eines Kunden
        /// </summary>
        /// <param name="customerId">ID des Kunden</param>
        /// <returns>Task</returns>
        public async Task JoinCustomer(Guid customerId)
        {
            var group = $"customer_{customerId}";
            await _hubContext.Groups.AddToGroupAsync(Context.ConnectionId, group);
        }
    }
}