change: sar rework, improved

src/NadekoBot/_common/NadekoModule.cs

@@ -100,6 +100,27 @@ public abstract class NadekoModule : ModuleBase
             return Task.CompletedTask;
         }
     }
+    
+    protected async Task<bool> CheckRoleHierarchy(IGuildUser target)
+    {
+        var curUser = ((SocketGuild)ctx.Guild).CurrentUser;
+        var ownerId = ctx.Guild.OwnerId;
+        var modMaxRole = ((IGuildUser)ctx.User).GetRoles().Max(r => r.Position);
+        var targetMaxRole = target.GetRoles().Max(r => r.Position);
+        var botMaxRole = curUser.GetRoles().Max(r => r.Position);
+        // bot can't punish a user who is higher in the hierarchy. Discord will return 403
+        // moderator can be owner, in which case role hierarchy doesn't matter
+        // otherwise, moderator has to have a higher role
+        if (botMaxRole <= targetMaxRole
+            || (ctx.User.Id != ownerId && targetMaxRole >= modMaxRole)
+            || target.Id == ownerId)
+        {
+            await Response().Error(strs.hierarchy).SendAsync();
+            return false;
+        }
+
+        return true;
+    }
 }
 
 public abstract class NadekoModule<TService> : NadekoModule