#nullable enable

using System;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;
using Volo.Abp.Domain.Repositories;
using Volo.Abp.Guids;
using Volo.Abp.Identity;
using Volo.Abp.MultiTenancy;
using Volo.Abp.Users;

namespace Sozsoft.Platform.Messenger;

[Authorize]
public class MessengerHub : Hub
{
    private readonly ICurrentTenant _currentTenant;
    private readonly ICurrentUser _currentUser;
    private readonly IGuidGenerator _guidGenerator;
    private readonly IRepository<IdentityUser, Guid> _userRepository;

    public MessengerHub(
        ICurrentTenant currentTenant,
        ICurrentUser currentUser,
        IGuidGenerator guidGenerator,
        IRepository<IdentityUser, Guid> userRepository)
    {
        _currentTenant = currentTenant;
        _currentUser = currentUser;
        _guidGenerator = guidGenerator;
        _userRepository = userRepository;
    }

    public override async Task OnConnectedAsync()
    {
        if (_currentUser.Id.HasValue)
        {
            await Groups.AddToGroupAsync(Context.ConnectionId, UserGroupName(_currentUser.Id.Value));
            await Groups.AddToGroupAsync(Context.ConnectionId, TenantGroupName());
        }

        await base.OnConnectedAsync();
    }

    public override async Task OnDisconnectedAsync(Exception? exception)
    {
        if (_currentUser.Id.HasValue)
        {
            await Groups.RemoveFromGroupAsync(Context.ConnectionId, UserGroupName(_currentUser.Id.Value));
            await Groups.RemoveFromGroupAsync(Context.ConnectionId, TenantGroupName());
        }

        await base.OnDisconnectedAsync(exception);
    }

    public async Task SendMessage(MessengerSendMessageDto input)
    {
        if (!_currentUser.Id.HasValue)
        {
            throw new HubException("Kullanıcı oturumu bulunamadı.");
        }

        var recipientIds = input.RecipientIds
            .Where(id => id != Guid.Empty)
            .Distinct()
            .ToList();

        if (recipientIds.Count == 0)
        {
            throw new HubException("En az bir alıcı seçilmelidir.");
        }

        if (input.Text.IsNullOrWhiteSpace() && input.Attachments.Count == 0)
        {
            throw new HubException("Mesaj veya dosya gönderilmelidir.");
        }

        var tenantId = _currentTenant.Id;
        var validRecipients = await _userRepository.GetListAsync(user =>
            recipientIds.Contains(user.Id) &&
            user.TenantId == tenantId &&
            user.IsActive);

        if (validRecipients.Count == 0)
        {
            throw new HubException("Bu tenant içinde geçerli alıcı bulunamadı.");
        }

        var senderName = _currentUser.Name ?? _currentUser.UserName ?? "Kullanıcı";
        var message = new MessengerMessageDto
        {
            Id = _guidGenerator.Create(),
            TenantId = tenantId,
            SenderId = _currentUser.Id.Value,
            SenderUserName = _currentUser.UserName ?? string.Empty,
            SenderName = senderName,
            RecipientIds = validRecipients.Select(user => user.Id).ToList(),
            Text = input.Text?.Trim(),
            Attachments = input.Attachments,
            SentAt = DateTime.UtcNow
        };

        var targetGroups = message.RecipientIds
            .Append(message.SenderId)
            .Distinct()
            .Select(UserGroupName)
            .ToList();

        await Clients.Groups(targetGroups).SendAsync("MessengerMessageReceived", message);
    }

    private string TenantKey => _currentTenant.Id?.ToString("N") ?? "host";

    private string TenantGroupName() => $"messenger:tenant:{TenantKey}";

    private string UserGroupName(Guid userId) => $"messenger:user:{TenantKey}:{userId:N}";
}