Cheap anvil repairs that don't increase the Prior Work Penalty.

[VonSparq]

Hello!
I have previously requested a more advanced version of this mechanic and since tried to implement a simpler solution which I partially failed at, but Billy showed interest in possibly implementing something like this so I thought making a formal feature request for this simplified system would be in order.

My idea was to make repairs only require resources, so you can disable Mending and XP farms on your server but still allow players to maintain their tools without breaking the XP bank 🤣.

What would this look like technically?
If a player inserts an item to repair into the anvil's first slot and a repair item (raw resources or not enchanted version of the same item) into the second slot, the repair would cost only 1 level and would not increase the Prior Work Penalty (the number that makes an item more expensive to repair/combine each time it goes through the anvil).

I'm including my faulty implementation of the requested system, it works properly when player is in creative but when they are in survival and the repaired item would normally throw "Too Expensive!" it does not allow for repair and I don't know how to fix that.
I doubt you'll need it because you are much better programmers then me but I though that it'd be rude not to offer:

    public void onPrepareAnvil(PrepareAnvilEvent event) {
        ItemStack grItmStck = event.getResult();
        if (grItmStck == null) return;
        ItemMeta grItmMt = grItmStck.getItemMeta();
        if (grItmMt == null) return;

        AnvilInventory gtInv = event.getInventory();
        ItemStack left = gtInv.getItem(0);
        if (left == null || left.getType() == Material.AIR) return;
        if (left.getType() == Material.ENCHANTED_BOOK) return;

        ItemStack right = gtInv.getItem(1);
        if (right == null || right.getType() == Material.AIR) return;
        if (!right.getEnchantments().isEmpty() || right.getType() == Material.ENCHANTED_BOOK) return;
        
        Repairable leftRepairable = (Repairable)left.getItemMeta();
        if (leftRepairable == null) return;
        int leftPriorWork = leftRepairable.getRepairCost();
        
        if (!left.getItemMeta().getDisplayName().equals(grItmMt.getDisplayName())) {
            gtInv.setRepairCost(2);
        }
        else {
            gtInv.setRepairCost(1);
        }
        ((Repairable) grItmMt).setRepairCost(leftPriorWork);
        grItmStck.setItemMeta(grItmMt);
        event.setResult(grItmStck);
    }
    //WTFPL 2.0 😆