MemberizerCommand.cs

using Discord;
using Discord.WebSocket;
using System.Linq;
using System.Threading.Tasks;
using static AcegikmoDiscordBot.Program;

namespace AcegikmoDiscordBot;

internal class MemberizerCommand
{
    private const ulong MembersRole = 528976700399419406UL;
    private readonly Log _log;

    public MemberizerCommand(Log log)
    {
        _log = log;
    }

    public static async Task Memberizer(Log log, SocketTextChannel channel, ulong desiredCount)
    {
        var guild = channel.Guild;
        var nonmembers = guild.Users.Where(user => !IsMember(user)).Select(user => user.Id).ToList();
        var counts = log.MessageCounts(nonmembers, desiredCount);
        var msg = string.Join("\n",
            counts.Select(item => $"{MentionUtils.MentionUser(item.authorId)} has sent {item.count} messages"));
        if (!string.IsNullOrEmpty(msg))
        {
            await channel.SendMessageAsync(msg);
        }
    }

    public async Task MessageReceivedAsync(SocketMessage message)
    {
        if (message.Author.Id == ASHL &&
            message.Content.StartsWith("!memberizer ") &&
            ulong.TryParse(message.Content["!memberizer ".Length..], out var desiredCount) &&
            message.Channel is SocketTextChannel channel)
        {
            await Memberizer(_log, channel, desiredCount);
        }

        if (message.Author.Id == ASHL && message is { Content: "!membercount", Channel: SocketGuildChannel ch })
        {
            var roles = string.Join(", ",
                ch.Guild.Roles.Select(role =>
                    $"{role.Name.Replace("@everyone", "at-everyone")}={role.Members.Count()}"));
            var msg = $"total={ch.Guild.MemberCount}, {roles}";
            await message.Channel.SendMessageAsync(msg);
        }

        if (message.Author.Id == ASHL && message is { Content: "!roles", Channel: SocketGuildChannel ch2 })
        {
            var msg = string.Join(", ",
                ch2.Guild.Roles.Select(role => $"{role.Name.Replace("@everyone", "at-everyone")}={role.Id}"));
            await message.Channel.SendMessageAsync(msg);
        }
    }

    private static bool IsMember(SocketGuildUser user)
    {
        foreach (var role in user.Roles)
        {
            if (role.Id == MembersRole)
            {
                return true;
            }
        }

        return false;
    }
}