Elementary/Elementary/Commands/Handler.cs

using System.Reflection;
using Discord.Audio;
using Discord.Commands;
using Discord.WebSocket;
using Elementary.Audio;

namespace Elementary.Commands;

public class Handler
{
    private readonly DiscordSocketClient _client;
    private readonly CommandService _commands;
    private readonly IServiceProvider _services;
    private readonly AudioManager _audioManager;
    private readonly MessageHandler _messageHandler;

    // Retrieve client and CommandService instance via ctor
    public Handler(DiscordSocketClient client, CommandService commands, IServiceProvider services,
        AudioManager audioManager, MessageHandler messageHandler)
    {
        _commands = commands;
        _client = client;
        _services = services;
        _audioManager = audioManager;
        _messageHandler = messageHandler;
    }

    public async Task Setup()
    {
        await _commands.AddModulesAsync(Assembly.GetEntryAssembly(), _services);

        _client.MessageReceived += HandleMessage;
    }

    private async Task HandleMessage(SocketMessage messageParam)
    {
        var message = messageParam as SocketUserMessage;
        if (message == null || message.Author.IsBot) return;

        var argPos = 0;

        if (message.HasCharPrefix('!', ref argPos) ||
            message.HasMentionPrefix(_client.CurrentUser, ref argPos))
        {
            SocketCommandContext context = new(_client, message);

            await _commands.ExecuteAsync(
                context,
                argPos,
                _services);
        }

        if (_audioManager.isConnected)
        {
            Console.WriteLine("Handling message");
            await _messageHandler.HandleMessage(message);
        }
    }
}