Update precondition logic; make methods obsolete

The current way of loading database information makes things confusing and difficult to follow, particularly with retrieving guild data and its second parameter.
A much better alternative should be considered, and accessed by means of extension methods.

ApplicationCommands/Preconditions.cs

@@ -10,17 +10,22 @@ namespace BirthdayBot.ApplicationCommands;
 /// That is, they must either have the Manage Server permission or be a member of the designated bot moderator role.
 /// </summary>
 class RequireBotModeratorAttribute : PreconditionAttribute {
-    public override string ErrorMessage => ":x: Only bot moderators may use this command.";
+    public const string FailMsg = "User did not pass the mod check.";
+    public const string Reply = ":x: You must be a moderator to use this command.";
 
-    public override async Task<PreconditionResult> CheckRequirementsAsync(IInteractionContext context,
+    public override string ErrorMessage => FailMsg;
-                                                                    ICommandInfo commandInfo, IServiceProvider services) {
+
+    public override async Task<PreconditionResult> CheckRequirementsAsync(
+        IInteractionContext context, ICommandInfo commandInfo, IServiceProvider services) {
         if (context.User is not SocketGuildUser user) {
-            return PreconditionResult.FromError("Mod check automatically failed due to non-guild context.");
+            return PreconditionResult.FromError("Failed due to non-guild context.");
         }
 
-        var gconf = await GuildConfiguration.LoadAsync(context.Guild.Id, false);
+        if (user.GuildPermissions.ManageGuild) return PreconditionResult.FromSuccess();
-        var isMod = gconf!.IsBotModerator(user);
+        var gconf = await ((SocketGuild)context.Guild).GetConfigAsync().ConfigureAwait(false);
-        if (isMod) return PreconditionResult.FromSuccess();
+        if (gconf.ModeratorRole.HasValue && user.Roles.Any(r => r.Id == gconf.ModeratorRole.Value))
-        else return PreconditionResult.FromError("User did not pass the mod check.");
+            return PreconditionResult.FromSuccess();
+
+        return PreconditionResult.FromError(FailMsg);
     }
 }

Data/GuildConfiguration.cs

@@ -125,6 +125,7 @@ class GuildConfiguration {
     /// Checks if the given user can be considered a bot moderator.
     /// Checks for either the Manage Guild permission or if the user is within a predetermined role.
     /// </summary>
+    [Obsolete("Usage should be phased out when text commands are removed. Use PreconditionAttribute from now on.", error: false)]
     public bool IsBotModerator(SocketGuildUser user)
         => user.GuildPermissions.ManageGuild || (ModeratorRole.HasValue && user.Roles.Any(r => r.Id == ModeratorRole.Value));
 
@@ -165,6 +166,7 @@ class GuildConfiguration {
     /// If true, this method shall not create a new entry and will return null if the guild does
     /// not exist in the database.
     /// </param>
+    [Obsolete("Begin using extension method to retrieve necessary data instead.", false)]
     public static async Task<GuildConfiguration?> LoadAsync(ulong guildId, bool nullIfUnknown) {
         // TODO nullable static analysis problem: how to indicate non-null return when nullIfUnknown parameter is true?
         using (var db = await Database.OpenConnectionAsync().ConfigureAwait(false)) {

Data/GuildUserConfiguration.cs

@@ -106,6 +106,7 @@ class GuildUserConfiguration {
     /// <summary>
     /// Attempts to retrieve a user's configuration. Returns a new, updateable instance if none is found.
     /// </summary>
+    [Obsolete("Migrate to using extension methods to retrieve necessary data instead.", false)]
     public static async Task<GuildUserConfiguration> LoadAsync(ulong guildId, ulong userId) {
         using var db = await Database.OpenConnectionAsync().ConfigureAwait(false);
         using var c = db.CreateCommand();
@@ -122,6 +123,7 @@ class GuildUserConfiguration {
     /// <summary>
     /// Gets all known user configuration records associated with the specified guild.
     /// </summary>
+    [Obsolete("Migrate to using extension methods to retrieve necessary data instead.", false)]
     public static async Task<IEnumerable<GuildUserConfiguration>> LoadAllAsync(ulong guildId) {
         using var db = await Database.OpenConnectionAsync().ConfigureAwait(false);
         using var c = db.CreateCommand();