using Microsoft.EntityFrameworkCore;
using Nuuru.Server.Models;

namespace Nuuru.Server.Data
{
    public static class AvatarLookupExtensions
    {
        public static Func<string, string?> CreateAvatarLookup(this ApplicationDbContext context)
        {
            var cache = new Dictionary<string, string?>(StringComparer.OrdinalIgnoreCase);

            return userName =>
            {
                if (cache.TryGetValue(userName, out var cached))
                    return cached;

                var user = context.Users
                    .AsNoTracking()
                    .Where(u => u.UserName == userName)
                    .Select(u => new { u.UserName, u.AvatarStorageIdentifier })
                    .FirstOrDefault();

                var url = user != null
                    ? ApplicationUser.GetAvatarUrl(user.UserName, user.AvatarStorageIdentifier)
                    : null;

                cache[userName] = url;
                return url;
            };
        }
    }
}