using Unity.Entities;
using Unity.NetCode;

namespace ProjectM.Simulation
{
    /// <summary>
    /// One (item, count) row in a player's PERSONAL inventory. The per-player DynamicBuffer of these is the
    /// server-authoritative source of what that player is carrying. A structural twin of
    /// <see cref="StatModifier"/>: a [GhostField] buffer with <see cref="SendToOwnerType.All"/> so the owning
    /// (predicting) client receives its own inventory — without it the owner, being the owner, would not get
    /// the owner-typed buffer at all and the HUD would read empty. BOTH fields carry [GhostField]; the
    /// [GhostComponent] attribute alone does NOT auto-replicate fields (an un-annotated field ships as a
    /// silent zero), so the annotations mirror <see cref="StorageEntry"/> field-for-field.
    ///
    /// REPLICATION DISCIPLINE — the ONLY writers are server-only: <see cref="ProjectM.Server.ResourceHarvestSystem"/>
    /// (harvest yield) and the deposit-to-base RPC handler, both in the plain server SimulationSystemGroup. So
    /// there is no predicted-loop double-apply and the owner never mispredicts its inventory — it is a pure
    /// server-authored snapshot. NEVER mutate this from a client predicted system (that would reintroduce a
    /// double-apply / mispredict path). ItemId is the same opaque ushort id space as <see cref="StorageEntry"/>
    /// and the <see cref="ItemDatabase"/> catalog.
    ///
    /// NOTE: adding this [GhostField] buffer CHANGES the player ghost serialization hash — the player prefab /
    /// subscene MUST be re-baked (consistently in both worlds) or the connect handshake desyncs.
    /// </summary>
    [GhostComponent(OwnerSendType = SendToOwnerType.All)]
    [InternalBufferCapacity(24)]
    public struct InventorySlot : IBufferElementData
    {
        /// <summary>Item carried in this slot (0 = empty/unused; aligns with InventoryMath's 0-id no-op).</summary>
        [GhostField] public ushort ItemId;

        /// <summary>Quantity in this slot (bounded by the item's StackMax when deposited via InventoryMath).</summary>
        [GhostField] public int Count;
    }
}