BotService.cs

using Discord;
using Discord.Commands;
using Discord.Interactions;
using Discord.WebSocket;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;

namespace Portal;

public class BotService(DiscordSocketClient discordSocketClient,
    InteractionService interactionService,
    InteractionHandler interactionHandler,
    CommandService commandService,
    CommandHandler commandHandler,
    IConfiguration configuration) : IHostedService
{
    public async Task StartAsync(CancellationToken cancellationToken)
    {
        CustomBotLogger customBotLogger = new();
        await interactionHandler.InitializeAsync();
        await commandHandler.InstallCommandsAsync();
        
        interactionService.Log += customBotLogger.BotLogger;
        commandService.Log += customBotLogger.BotLogger;
        discordSocketClient.Log += customBotLogger.BotLogger;

        discordSocketClient.Ready += async () =>
        {
            _ = Task.Run(async () =>
            {
                // Setting up slash commands and context commands
                ulong guildId = Convert.ToUInt64(configuration["Bot:GuildId"]);
                var guild = discordSocketClient.GetGuild(guildId);
                await guild.BulkOverwriteApplicationCommandAsync(new ApplicationCommandProperties[]
                {
                    AddContextCommand().Build()
                });
                await interactionService.RegisterCommandsToGuildAsync(guildId);
            }, cancellationToken);
            await Task.CompletedTask;
        };

        // Starting discord socket client
        await discordSocketClient.LoginAsync(TokenType.Bot, configuration["DISCORD_BOT_TOKEN"]);
        await discordSocketClient.StartAsync();

        // Setting bot's activity
        await discordSocketClient.SetGameAsync(configuration["RichPresence:CustomMessage"], 
            null, ActivityType.CustomStatus);
    }

    public async Task StopAsync(CancellationToken cancellationToken)
    {
        // Stops the discord socket client instance and logs out (graceful shutdown).
        await discordSocketClient.LogoutAsync();
        await discordSocketClient.StopAsync();
    }

    private MessageCommandBuilder AddContextCommand()
    {
        // Create a context command named "Open Portal"
        var guildMessageCommand = new MessageCommandBuilder()
            .WithName("Open Portal")
            .WithContextTypes(InteractionContextType.Guild, InteractionContextType.PrivateChannel);
        return guildMessageCommand;
    }
}