using Unity.Entities;

namespace ProjectM.Simulation
{
    /// <summary>
    /// The ONE collector of the permanent-meta save slice (the SaveStructureScan idiom): reads the director's
    /// replicated <see cref="MetaTierState"/> buffer + server-only <see cref="MetaCounters"/> into the
    /// <see cref="SaveData"/> v6 fields. Shared by BOTH save writers — <c>SaveWriteSystem</c> (autosave) AND
    /// <c>WorldLauncher.TrySaveFromServer</c> (quit-to-menu) — so the writers can never drift; the quit path
    /// silently omitting these fields would WIPE all permanent progression on the most common exit (the meta
    /// review's top blocker). Rows are copied VERBATIM (unknown ids round-trip).
    /// </summary>
    public static class MetaSaveScan
    {
        public static void Collect(EntityManager em, Entity director,
            out MetaUpgradeSave[] rows, out int runsCompleted, out int maxDepthReached)
        {
            rows = System.Array.Empty<MetaUpgradeSave>();
            runsCompleted = 0;
            maxDepthReached = 0;

            if (em.HasBuffer<MetaTierState>(director))
            {
                var buf = em.GetBuffer<MetaTierState>(director, true);
                rows = new MetaUpgradeSave[buf.Length];
                for (int i = 0; i < buf.Length; i++)
                    rows[i] = new MetaUpgradeSave { ClassId = buf[i].ClassId, UpgradeId = buf[i].UpgradeId, Tier = buf[i].Tier };
            }

            if (em.HasComponent<MetaCounters>(director))
            {
                var counters = em.GetComponentData<MetaCounters>(director);
                runsCompleted = counters.RunsCompleted;
                maxDepthReached = counters.MaxDepthReached;
            }
        }
    }
}