Rework regens to match modern clients

zone/spells.cpp

@@ -4234,6 +4234,19 @@ bool Mob::IsAffectedByBuff(uint16 spell_id)
 	return false;
 }
 
+bool Mob::IsAffectedByBuffByGlobalGroup(GlobalGroup group)
+{
+	int buff_count = GetMaxTotalSlots();
+	for (int i = 0; i < buff_count; ++i) {
+		if (buffs[i].spellid == SPELL_UNKNOWN)
+			continue;
+		if (spells[buffs[i].spellid].spell_category == static_cast<int>(group))
+			return true;
+	}
+
+	return false;
+}
+
 // checks if 'this' can be affected by spell_id from caster
 // returns true if the spell should fail, false otherwise
 bool Mob::IsImmuneToSpell(uint16 spell_id, Mob *caster)