SupportChild/Commands/AddCategoryCommand.cs

using System.Threading.Tasks;
using DSharpPlus.Entities;
using DSharpPlus.SlashCommands;
using DSharpPlus.SlashCommands.Attributes;

namespace SupportChild.Commands;

public class AddCategoryCommand : ApplicationCommandModule
{
    [SlashRequireGuild]
    [SlashCommand("addcategory", "Adds a category to the ticket bot letting users open tickets in them.")]
    public async Task OnExecute(InteractionContext command, [Option("Title", "The name to display on buttons and in selection boxes.")] string title, [Option("Category", "The category to add.")] DiscordChannel category)
    {
        if (!category.IsCategory)
        {
            await command.CreateResponseAsync(new DiscordEmbedBuilder
            {
                Color = DiscordColor.Red,
                Description = "That channel is not a category."
            }, true);
            return;
        }

        if (string.IsNullOrWhiteSpace(title))
        {
            await command.CreateResponseAsync(new DiscordEmbedBuilder
            {
                Color = DiscordColor.Red,
                Description = "Invalid category title specified."
            }, true);
            return;
        }

        if (Database.TryGetCategory(category.Id, out Database.Category _))
        {
            await command.CreateResponseAsync(new DiscordEmbedBuilder
            {
                Color = DiscordColor.Red,
                Description = "That category is already registered."
            }, true);
            return;
        }

        if (Database.TryGetCategory(title, out Database.Category _))
        {
            await command.CreateResponseAsync(new DiscordEmbedBuilder
            {
                Color = DiscordColor.Red,
                Description = "There is already a category with that title."
            }, true);
            return;
        }

        if (Database.AddCategory(title, category.Id))
        {
            await command.CreateResponseAsync(new DiscordEmbedBuilder
            {
                Color = DiscordColor.Green,
                Description = "Category added."
            }, true);
        }
        else
        {
            await command.CreateResponseAsync(new DiscordEmbedBuilder
            {
                Color = DiscordColor.Red,
                Description = "Error: Failed adding the category to the database."
            }, true);
        }
    }
}