DiscordAvatar.cs

using Discord;

namespace Yonom.DiscordTools
{
    static class DiscordAvatar
    {
        // for documentation purposes only
        private static enum DefaultAvatars
        {
            blurple = 0,
            grey    = 1,
            green   = 2,
            orange  = 3,
            red     = 4,

            total   = 5
        }

        public static string GetAvatarUrlOrDefault(this IUser user)
        {
            return user.GetAvatarUrl() ?? GetDefaultAvatarUrl(user);
        }


        public static string GetDefaultAvatarUrl(this IUser user)
        {
            var imageId = user.DiscriminatorValue % (int)DefaultAvatars.total
            return $"https://cdn.discordapp.com/embed/avatars/{imageID}.png";
        }
    }
}