#if UNITY_EDITOR
using Unity.Entities;
using Unity.NetCode;

namespace ProjectM.Simulation
{
    /// <summary>
    /// EDITOR-ONLY dev convenience for the M4 LAN flow. With auto-connect disabled in <c>GameBootstrap</c>,
    /// this seeds a <see cref="ConnectionConfig"/> in each world on its first update so entering Play "just
    /// works" multi-client: the server world hosts on loopback and every client / thin-client world joins
    /// it — reproducing the old single-key playflow but for N players. Runs once per world then disables
    /// itself, and skips seeding if a <see cref="ConnectionConfig"/> already exists (e.g. set by
    /// ConnectionUI). Does not exist in player builds.
    /// </summary>
    [WorldSystemFilter(WorldSystemFilterFlags.ServerSimulation | WorldSystemFilterFlags.ClientSimulation | WorldSystemFilterFlags.ThinClientSimulation)]
    public partial struct EditorAutoHostSystem : ISystem
    {
        public void OnUpdate(ref SystemState state)
        {
            state.Enabled = false; // run exactly once per world

            if (SystemAPI.HasSingleton<ConnectionConfig>())
                return;

            const ushort port = 7979;
            var cfg = state.WorldUnmanaged.IsServer()
                ? new ConnectionConfig { Mode = ConnectionMode.Host, Address = "127.0.0.1", Port = port, Requested = true }
                : new ConnectionConfig { Mode = ConnectionMode.Join, Address = "127.0.0.1", Port = port, Requested = true };

            var e = state.EntityManager.CreateEntity();
            state.EntityManager.AddComponentData(e, cfg);
        }
    }
}
#endif