using System.Text.RegularExpressions;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;
using Nuuru.Server.Extensions;
using Nuuru.Server.Services;

namespace Nuuru.Server.Hubs;

public static partial class LiveUpdateGroups
{
    public static string PostComments(int postId) => $"post-comments:{postId}";
    public static string Thread(int threadId) => $"thread:{threadId}";
    public static string Conversation(Guid conversationId) => $"conversation:{conversationId}";

    [GeneratedRegex(@"^(post-comments|thread):\d+$|^conversation:[0-9a-fA-F\-]{36}$")]
    public static partial Regex ValidGroupPattern();

    [GeneratedRegex(@"^conversation:([0-9a-fA-F\-]{36})$")]
    public static partial Regex ConversationGroupPattern();
}

public static class LiveUpdateEvents
{
    public const string Revalidate = "Revalidate";
}

public static class LiveUpdateHubExtensions
{
    public static Task NotifyGroupAsync(this IHubContext<LiveUpdateHub> hub, string group) =>
        hub.Clients.Group(group).SendAsync(LiveUpdateEvents.Revalidate);
}

[Authorize]
public class LiveUpdateHub : Hub
{
    private readonly IConversationService _conversationService;

    public LiveUpdateHub(IConversationService conversationService)
    {
        _conversationService = conversationService;
    }

    public async Task JoinGroup(string group)
    {
        if (!LiveUpdateGroups.ValidGroupPattern().IsMatch(group))
            throw new HubException("Invalid group name.");

        // Conversation groups require participant check
        var conversationMatch = LiveUpdateGroups.ConversationGroupPattern().Match(group);
        if (conversationMatch.Success)
        {
            var userId = Context.User?.GetUserId();
            if (userId == null)
                throw new HubException("Not authenticated.");

            var conversationId = Guid.Parse(conversationMatch.Groups[1].Value);
            if (!await _conversationService.IsParticipantAsync(conversationId, userId.Value))
                throw new HubException("Not a participant.");
        }

        await Groups.AddToGroupAsync(Context.ConnectionId, group);
    }

    public Task LeaveGroup(string group)
    {
        if (!LiveUpdateGroups.ValidGroupPattern().IsMatch(group))
            throw new HubException("Invalid group name.");

        return Groups.RemoveFromGroupAsync(Context.ConnectionId, group);
    }
}