namespace Ashwild.Inventory
{
    /// <summary>
    /// A container-agnostic snapshot of what a slot holds: the item, how many, and the remaining uses
    /// of this concrete instance (-1 when the item does not track uses). It is the common currency
    /// between every container — the player's inventory, a chest, or a stack in flight over the network —
    /// so the transfer rules can be written once without knowing where a slot lives.
    ///
    /// Carrying <see cref="Uses"/> is what keeps a half-worn tool half-worn when it changes slot: writing
    /// a slot back without it silently repairs the item to full.
    /// </summary>
    public struct SlotContent
    {
        public ItemData Item;
        public int Quantity;
        public int Uses;

        /// <summary>
        /// True when this snapshot holds nothing — no item, or a quantity that ran out.
        /// </summary>
        public bool IsEmpty => Item == null || Quantity <= 0;

        /// <summary>
        /// The empty snapshot, used to clear a slot.
        /// </summary>
        public static SlotContent Empty => new SlotContent { Item = null, Quantity = 0, Uses = -1 };

        /// <summary>
        /// Builds a snapshot, normalising the uses of an item that does not track them to -1.
        /// </summary>
        public static SlotContent Of(ItemData item, int quantity, int uses)
        {
            if (item == null || quantity <= 0) return Empty;
            return new SlotContent
            {
                Item = item,
                Quantity = quantity,
                Uses = item.HasUses ? uses : -1
            };
        }
    }
}