KasinoBot/Client.cs

using Discord;
using Discord.Commands;
using Discord.WebSocket;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace KasinoBot
{
    public class Client
    {
        private static DiscordSocketClient? client;
        private CommandService? commandService;
        private ServiceProvider? services;

        private async Task MessageReceived (SocketMessage rawMessage)
        {
            if (commandService == null || services == null)
                return;

            if (rawMessage is not SocketUserMessage message)
                return;

            if (message.Source != MessageSource.User)
                return;

            var argPos = 0;
            if (!message.HasCharPrefix('!', ref argPos))
                return;

            var context = new SocketCommandContext(client, message);
            await commandService.ExecuteAsync(context, argPos, services);
        }

        public async Task Initialize()
        {
            Console.WriteLine("Initializing...");

            using (services = GetServices())
            {
                // Initialize Discord Socket Client and Command Service
                client = services.GetRequiredService<DiscordSocketClient>();
                commandService = services.GetRequiredService<CommandService>();

                // add log handlers
                client.Log += LogAsync;
                client.MessageReceived += MessageReceived;
                client.Ready += ReadyAsync;

                services.GetRequiredService<CommandService>().Log += LogAsync;

                // Start Discord Socket Client
                await client.LoginAsync(TokenType.Bot, Environment.GetEnvironmentVariable("TOKEN"));
                await client.StartAsync();

                // Initialize command handler
                await services.GetRequiredService<CommandHandler>().InitializeAsync();

                // Hang there!
                await Task.Delay(Timeout.Infinite);
            }
        }

        private ServiceProvider GetServices()
        {
            return new ServiceCollection()
                .AddSingleton<DiscordSocketClient>()
                .AddSingleton<CommandService>()
                .AddSingleton<CommandHandler>()
                .BuildServiceProvider();
        }

        private Task ReadyAsync()
        {
            Console.WriteLine($"{client?.CurrentUser} is connected!");
            return Task.CompletedTask;
        }

        private Task LogAsync(LogMessage arg)
        {
            Console.WriteLine(arg.ToString());
            return Task.CompletedTask;
        }
    }
}