DiscordBotHostedService.cs

internal class DiscordBotHostedService(ILogger<DiscordBotHostedService> logger, DiscordClient discord) : IHostedService
{
    private readonly ILogger<DiscordBotHostedService> _logger = logger;
    private readonly DiscordClient _discordClient = discord;

    public async Task StartAsync(CancellationToken cancellationToken)
    {
        _discordClient.SessionCreated += OnSessionCreated;
        _discordClient.GuildAvailable += OnGuildAvailable;
        _discordClient.ClientErrored += OnClientError;
        
        await _discordClient.ConnectAsync();

        await Task.Delay(-1);
    }
 

    public Task StopAsync(CancellationToken cancellationToken)
    {
        return _discordClient.DisconnectAsync();
    }

    private async Task OnSessionCreated(DiscordClient sender, SessionCreatedEventArgs e)
    {
        sender.Logger.LogInformation(Program.BotEventId, "Client is ready to process events.");

        await sender.UpdateStatusAsync(new DiscordActivity()
        {
            ActivityType = Program.Config.Discord.DefaultActivityType,
            Name = Program.Config.Discord.DefaultActivity
        }, DiscordUserStatus.Online);
    }

    private Task OnGuildAvailable(DiscordClient sender, GuildAvailableEventArgs e)
    {

        Thread.CurrentThread.Name = "MainThread";

        sender.Logger.LogInformation(Program.BotEventId, "Guild available: {GuildName}", e.Guild.Name);

        return Task.CompletedTask;
    }

    private Task OnClientError(DiscordClient sender, ClientErrorEventArgs e)
    {
        Thread.CurrentThread.Name = "MainThread";

        sender.Logger.LogError(Program.BotEventId, e.Exception, "Exception occured");

        return Task.CompletedTask;
    }

    private async Task OnCommandExecuted(CommandsExtension sender, DSharpPlus.Commands.EventArgs.CommandExecutedEventArgs e)
    {
        e.Context.Client.Logger.LogInformation(Program.BotEventId, "{Username} successfully executed '{CommandName}'", e.Context.User.Username, e.Context.Command.Name);

        await e.Context.Client.UpdateStatusAsync(new DiscordActivity()
        {
            ActivityType = Program.Config.Discord.DefaultActivityType,
            Name = Program.Config.Discord.DefaultActivity
        }, DiscordUserStatus.Online);

    }

    private async Task OnCommandErrored(CommandsExtension sender, DSharpPlus.Commands.EventArgs.CommandErroredEventArgs e)
    {
        e.Context.Client.Logger.LogError(Program.BotEventId, "{Username} tried executing '{CommandName}' but it errored: {Type}: {Message}", e.Context.User.Username, e.Context?.Command.Name ?? "<unknown command>", e.Exception.GetType(), e.Exception.Message ?? "<no message>");

        if (e.Exception is ChecksFailedException)
        {
            var emoji = DiscordEmoji.FromName(e.Context.Client, ":no_entry:");

            var embed = new DiscordEmbedBuilder
            {
                Title = "Access denied",
                Description = $"{emoji} You do not have the permissions required to execute this command.",
                Color = new DiscordColor(0xFF0000)
            };
            await e.Context.RespondAsync(new DiscordInteractionResponseBuilder().WithContent($"{embed}"));
        }

        await e.Context.Client.UpdateStatusAsync(new DiscordActivity()
        {
            ActivityType = DiscordActivityType.Watching,
            Name = "Errors!"
        }, DiscordUserStatus.DoNotDisturb);
    }
}