using ProjectM.Simulation;
using Unity.Burst;
using Unity.Collections;
using Unity.Entities;
using Unity.NetCode;

namespace ProjectM.Server
{
    /// <summary>
    /// SERVER-ONLY decoy-wisp lifecycle: despawns a decoy ghost when its Health is spent (Husks "killed" it) or
    /// its <see cref="DecoyTag.ExpireTick"/> lifetime elapses. Server-authoritative ghost despawn (the client's
    /// copy is removed by GhostSendSystem — never DestroyEntity a ghost client-side). The decoy draws aggro via
    /// <c>EnemyAISystem</c>'s decoy target set; this system only ends its life. Presence-gated on DecoyTag.
    /// </summary>
    [BurstCompile]
    [WorldSystemFilter(WorldSystemFilterFlags.ServerSimulation)]
    [UpdateInGroup(typeof(SimulationSystemGroup))]
    public partial struct DecoySystem : ISystem
    {
        [BurstCompile]
        public void OnCreate(ref SystemState state)
        {
            state.RequireForUpdate<NetworkTime>();
            state.RequireForUpdate<DecoyTag>();
        }

        [BurstCompile]
        public void OnUpdate(ref SystemState state)
        {
            var serverTick = SystemAPI.GetSingleton<NetworkTime>().ServerTick;
            if (!serverTick.IsValid) return;
            var ecb = new EntityCommandBuffer(Allocator.Temp);
            foreach (var (decoy, hp, e) in
                     SystemAPI.Query<RefRO<DecoyTag>, RefRO<Health>>().WithEntityAccess())
            {
                bool expired = decoy.ValueRO.ExpireTick != 0u
                               && !new NetworkTick(decoy.ValueRO.ExpireTick).IsNewerThan(serverTick);
                if (hp.ValueRO.Current <= 0f || expired)
                    ecb.DestroyEntity(e);
            }
            ecb.Playback(state.EntityManager);
            ecb.Dispose();
        }
    }
}