Knots/Knots/Endpoints/Discussion/GetDiscussionMembersEndpoint.cs

using System.Security.Claims;
using FastEndpoints;
using Microsoft.EntityFrameworkCore;

namespace Knots.Endpoints.Discussion;

public class GetDiscussionMembersEndpoint(KnotsDbContext db) : EndpointWithoutRequest<List<string>>
{
    public override void Configure()
    {
        Get("/discussions/{discussionId}/members");
    }

    public override async Task HandleAsync(CancellationToken ct)
    {
        int discussionId = Route<int>("discussionId");

        Models.Discussion? discussion = await db.Discussions
            .Include(d => d.UserDiscussions)
            .ThenInclude(ud => ud.User)
            .SingleOrDefaultAsync(d => d.Id == discussionId, ct);

        if (discussion is null)
        {
            await SendNotFoundAsync(ct);
            return;
        }

        List<string> members = discussion.UserDiscussions
            .Select(ud => ud.User.Username!)
            .ToList();

        await SendOkAsync(members, ct);
    }
}