BirthdayBot/ApplicationCommands/Preconditions/RequireBotModerator.cs

using BirthdayBot.Data;
using Discord.Interactions;

namespace BirthdayBot.ApplicationCommands;

/// <summary>
/// Precondition requiring the executing user be recognized as a bot moderator.<br/>
/// A bot moderator has either the Manage Server permission or is a member of the designated bot moderator role.
/// </summary>
class RequireBotModeratorAttribute : PreconditionAttribute {
    public const string Error = "User did not pass the mod check.";
    public const string Reply = ":x: You must be a moderator to use this command.";

    public override string ErrorMessage => Error;

    public override Task<PreconditionResult> CheckRequirementsAsync(
        IInteractionContext context, ICommandInfo commandInfo, IServiceProvider services) {
        // A bot moderator can only exist in a guild context, so we must do this check.
        // This check causes this precondition to become a functional equivalent to RequireGuildContextAttribute...
        if (context.User is not SocketGuildUser user)
            return Task.FromResult(PreconditionResult.FromError(RequireGuildContextAttribute.Error));

        if (user.GuildPermissions.ManageGuild) return Task.FromResult(PreconditionResult.FromSuccess());
        using var db = new BotDatabaseContext();
        var checkRole = (ulong?)db.GuildConfigurations
            .Where(g => g.GuildId == (long)((SocketGuild)context.Guild).Id)
            .Select(g => g.RoleId).FirstOrDefault();
        if (checkRole.HasValue && user.Roles.Any(r => r.Id == checkRole.Value))
            return Task.FromResult(PreconditionResult.FromSuccess());

        return Task.FromResult(PreconditionResult.FromError(Error));
    }
}