#if UNITY_EDITOR
using ProjectM.Simulation;
using Unity.Collections;
using Unity.Entities;
using Unity.NetCode;
using UnityEngine;

namespace ProjectM.Client
{
    /// <summary>
    /// MC-0 — EDITOR-ONLY client owner of the local <see cref="TuningConfig"/> singleton (the value the PREDICTED
    /// DashSystem reads on this client). Each tick it (1) drains any authoritative <see cref="DebugTuningReport"/>
    /// into the <see cref="TuningReadout"/> static, then (2) pushes <see cref="TuningReadout.Current"/> into the
    /// client TuningConfig singleton. The overlay mutates the readout OPTIMISTICALLY via
    /// <see cref="TuningReadout.SetLocal"/> (so the tuner's own dash uses a nudged value instantly — instant, then
    /// EVENTUALLY CONSISTENT with the server within ~1 RTT once the SetTuning RPC lands and the next report
    /// reconciles). Runs EVERY tick (no RequireForUpdate) so an overlay-only change with no report still reaches the
    /// singleton. Plain client <see cref="SimulationSystemGroup"/> (mutated at most once/tick → the predicted
    /// re-sim reads a per-tick-constant value); non-Burst (touches a managed static). This DELIBERATELY extends the
    /// DevTelemetry pattern (which writes only a static) with a per-world singleton; the release path has no such
    /// system, so DashSystem's <c>TryGetSingleton ? : Defaults()</c> fallback is the permanent release behaviour.
    /// </summary>
    [WorldSystemFilter(WorldSystemFilterFlags.ClientSimulation)]
    [UpdateInGroup(typeof(SimulationSystemGroup))]
    public partial struct DevTuningReceiveSystem : ISystem
    {
        public void OnCreate(ref SystemState state)
        {
            if (state.GetEntityQuery(ComponentType.ReadWrite<TuningConfig>()).IsEmpty)
            {
                var e = state.EntityManager.CreateEntity(typeof(TuningConfig));
                state.EntityManager.SetComponentData(e, TuningConfig.Defaults());
            }
        }

        public void OnUpdate(ref SystemState state)
        {
            // (1) Authoritative server snapshot wins — overwrite the readout (FULL state).
            var ecb = new EntityCommandBuffer(Allocator.Temp);
            foreach (var (report, reqEntity) in
                     SystemAPI.Query<RefRO<DebugTuningReport>>()
                         .WithAll<ReceiveRpcCommandRequest>().WithEntityAccess())
            {
                TuningReadout.Current = TuningConfig.FromReport(report.ValueRO);
                TuningReadout.Initialized = true;
                ecb.DestroyEntity(reqEntity);
            }
            ecb.Playback(state.EntityManager);
            ecb.Dispose();

            // (2) Push the readout (authoritative, or optimistic SetLocal, or Defaults()) into the client singleton.
            if (SystemAPI.TryGetSingletonEntity<TuningConfig>(out var cfgEntity))
                state.EntityManager.SetComponentData(cfgEntity, TuningReadout.Current);
        }
    }

    /// <summary>
    /// MC-0 — static bridge from the ECS tuning receiver to the IMGUI <c>DebugOverlay</c> (so the overlay reads/sets
    /// a plain struct, never ECS state). <see cref="Current"/> seeds to <see cref="TuningConfig.Defaults"/> on
    /// play-enter (so it matches the server's seeded Defaults before the first report). <see cref="SetLocal"/> is the
    /// overlay's OPTIMISTIC apply — it runs the same <see cref="TuningConfig.Apply"/> clamp so an overlay nudge can
    /// never feed a 0/negative into the predicted DashSystem.
    /// </summary>
    public static class TuningReadout
    {
        public static TuningConfig Current;

        /// <summary>True once an authoritative server report has been received (else <see cref="Current"/> is Defaults()).</summary>
        public static bool Initialized;

        /// <summary>Optimistic local apply (overlay button) — clamped via <see cref="TuningConfig.Apply"/>.</summary>
        public static void SetLocal(byte knob, float value) => TuningConfig.Apply(ref Current, knob, value);

        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
        static void Reset()
        {
            Current = TuningConfig.Defaults();
            Initialized = false;
        }
    }
}
#endif