using Unity.Entities;
using Unity.NetCode;

namespace ProjectM.Simulation
{
    /// <summary>
    /// One equipment slot on the player. The per-player buffer holds exactly <see cref="EquipSlotId.Count"/>
    /// rows in fixed slot order (the buffer INDEX is the slot — Weapon=0/Armor=1/Trinket=2/Tool=3), so only the
    /// equipped item id needs to replicate; there is no separate Slot field to desync. A [GhostField]
    /// <see cref="SendToOwnerType.All"/> buffer (a <see cref="StatModifier"/>/<see cref="InventorySlot"/> twin)
    /// so the owning client's HUD can show its loadout; the server is the SOLE writer (EquipSystem).
    ///
    /// The actual effects — AbilityRef.Id from the Weapon slot + StatModifiers per slot — are applied
    /// EVENT-DRIVEN by EquipSystem (once per equip/unequip), NOT re-derived from this buffer each tick; this
    /// buffer is the replicated record of WHAT is equipped (HUD-facing + persistence-ready), not the effect.
    /// NOTE: adding this [GhostField] buffer changes the player ghost serialization hash → the player
    /// prefab/subscene MUST be re-baked consistently in both worlds (see <see cref="InventorySlot"/>).
    /// </summary>
    [GhostComponent(OwnerSendType = SendToOwnerType.All)]
    [InternalBufferCapacity(4)]
    public struct EquipmentSlot : IBufferElementData
    {
        /// <summary>Item equipped in this slot (0 = empty). The buffer INDEX is the <see cref="EquipSlotId"/>.</summary>
        [GhostField] public ushort ItemId;
    }
}