using Unity.Entities;
using Unity.Mathematics;
using Unity.NetCode;

namespace ProjectM.Simulation
{
    /// <summary>
    /// Structure type ids (a byte, not an enum, per the cross-assembly enum-in-Burst hazard). Ids 1-4 are
    /// RETIRED (EB-2 turret defense + M7 automation machines, deleted in the LANTERN purge) and stay reserved
    /// so PlacedStructure.Type's [GhostField] serializer + old save bytes never re-mean.
    /// </summary>
    public static class StructureType
    {
        public const byte None = 0;
        // RETIRED ids — reserved, do not reuse:
        public const byte Turret = 1;
        public const byte Harvester = 2;
        public const byte Fabricator = 3;
        public const byte Conveyor = 4;
        // Live buildables:
        public const byte Wall = 5;
        public const byte Pylon = 6;
    }

    /// <summary>
    /// A built base structure occupying one grid cell. An ownerless INTERPOLATED ghost (RegionTag{Base},
    /// world-owned, runtime-spawned by BuildPlaceSystem). <see cref="Type"/> is the only replicated field
    /// (a cheap byte for client visual branching); <see cref="Cell"/> is server-only (clients derive it from
    /// the replicated LocalTransform via <see cref="BaseGridMath.WorldToCell"/>, so it stays off the wire).
    /// <see cref="NextTick"/> / <see cref="LastProcessedTick"/> are server-only raw NetworkTick values
    /// (<see cref="TickUtil.NonZero"/>-guarded; 0 = inactive), kept for future timed structures (the turret
    /// cooldown + production catch-up that used them are retired — LANTERN purge).
    /// </summary>
    public struct PlacedStructure : IComponentData
    {
        /// <summary>Structure type (see <see cref="StructureType"/>); the only replicated field.</summary>
        [GhostField] public byte Type;

        /// <summary>Occupied grid cell (server-only; clients derive it from LocalTransform).</summary>
        public int2 Cell;

        /// <summary>Next action tick (server-only). 0 = inactive.</summary>
        public uint NextTick;

        /// <summary>Last tick this structure was processed (server-only). Stamped at spawn.</summary>
        public uint LastProcessedTick;
    }

    /// <summary>
    /// One row of the build catalog: cost + prefab per structure type. Modeled on AbilityPrefabElement
    /// (prefab baked via GetEntity, NEVER inside a blob — blobs don't remap entity refs).
    /// </summary>
    public struct StructureCatalogEntry : IBufferElementData
    {
        public byte Type;
        public Entity Prefab;
        public byte CostResourceId;
        public int CostAmount;
    }

    /// <summary>Tag on the baked singleton carrying the <see cref="StructureCatalogEntry"/> buffer (the build cost/prefab table).</summary>
    public struct StructureCatalog : IComponentData { }

    /// <summary>
    /// Marks a structure PLACED by a player at runtime (BuildPlaceSystem) or restored from a save — i.e. the
    /// persistable set, as opposed to anything baked into the subscene. SaveWriteSystem scans only these and
    /// BaseRestoreSystem re-adds the tag, so save/restore is the single source of truth for player builds.
    /// Server-only (not replicated). (Re-homed here from the retired automation components — LANTERN purge.)
    /// </summary>
    public struct RuntimePlacedTag : IComponentData { }
}