CheckAttribute.cs

using System;
using System.Threading.Tasks;
using Ultz.Extensions.Commands.Built;
using Ultz.Extensions.Commands.Context;
using Ultz.Extensions.Commands.Results.User;

namespace Ultz.Extensions.Commands.Attributes.Checks
{
    /// <summary>
    /// Represents a <see cref="Built.Module" /> or <see cref="Built.Command" /> check that has to succeed before it can be
    /// executed.
    /// </summary>
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true)]
    public abstract class CheckAttribute : Attribute
    {
        /// <summary>
        /// Gets the <see cref="Built.Module" /> this <see cref="CheckAttribute" /> is for.
        /// <see langword="null" /> if this check is for a <see cref="Built.Command" />.
        /// </summary>
        public Module Module { get; internal set; }

        /// <summary>
        /// Gets the <see cref="Built.Command" /> this <see cref="CheckAttribute" /> is for.
        /// <see langword="null" /> if this check is for a <see cref="Built.Module" />.
        /// </summary>
        public Command Command { get; internal set; }

        /// <summary>
        /// Gets or sets the group for this check.
        /// </summary>
        /// <remarks>
        /// Grouped checks act as if they were put side by side with the logical OR operator (||) in between.
        /// </remarks>
        public string Group { get; set; }

        /// <summary>
        /// A method which determines whether the <see cref="Module" /> or <see cref="Command" /> can execute in given
        /// circumstances.
        /// </summary>
        /// <param name="context"> The <see cref="CommandContext" /> used during execution. </param>
        /// <returns>
        /// A <see cref="CheckResult" /> which determines whether this <see cref="CheckAttribute" /> succeeded or not.
        /// </returns>
        public abstract ValueTask<CheckResult> CheckAsync(CommandContext context);
    }
}