Project-M/Assets/_Project/Scripts/Server/Combat/EnemyAISystem.cs

using ProjectM.Simulation;
using Unity.Burst;
using Unity.Collections;
using Unity.Entities;
using Unity.Mathematics;
using Unity.NetCode;
using Unity.Physics;
using Unity.Transforms;

namespace ProjectM.Server
{
    /// <summary>
    /// Server-authoritative Husk AI: each tick every Husk seeks the nearest LIVING player and strikes on
    /// contact. Husks are OWNERLESS INTERPOLATED ghosts (not predicted), so this runs SERVER-ONLY in the plain
    /// <see cref="SimulationSystemGroup"/> — writing <see cref="LocalTransform"/> directly (replicated to clients
    /// by the stock LocalTransform default variant; no hand-written <c>[GhostField]</c>). Ordered
    /// <c>[UpdateAfter(PredictedSimulationSystemGroup)]</c> (the predicted group is OrderFirst, so UpdateBefore is ignored) so a contact <see cref="DamageEvent"/> appended this
    /// tick is drained the following tick by <see cref="HealthApplyDamageSystem"/> (which runs inside the predicted
    /// group on the server). No <c>Simulate</c> filter: interpolated ghosts are not predicted and the server has
    /// no rollback, so every Husk advances exactly once per tick. Movement/attack math is the pure, deterministic
    /// <see cref="EnemyAIMath"/>; server fixed-step <c>SystemAPI.Time.DeltaTime</c> is correct here (not the
    /// rollback loop). Structural-free: the only deferred op is appending to the player's DamageEvent buffer.
    /// </summary>
    [BurstCompile]
    [WorldSystemFilter(WorldSystemFilterFlags.ServerSimulation)]
    [UpdateInGroup(typeof(SimulationSystemGroup))]
    [UpdateAfter(typeof(PredictedSimulationSystemGroup))]
    public partial struct EnemyAISystem : ISystem
    {
        EntityQuery m_EnemyProjectiles;

        [BurstCompile]
        public void OnCreate(ref SystemState state)
        {
            state.RequireForUpdate<NetworkTime>();
            state.RequireForUpdate(state.GetEntityQuery(ComponentType.ReadOnly<EnemyTag>()));
            m_EnemyProjectiles = state.GetEntityQuery(ComponentType.ReadOnly<EnemyProjectile>());
        }

        [BurstCompile]
        public void OnUpdate(ref SystemState state)
        {
            // Snapshot living player targets once this tick (stable query order).
            var playerEntities = new NativeList<Entity>(Allocator.Temp);
            var playerPositions = new NativeList<float3>(Allocator.Temp);
            var playerRegions = new NativeList<byte>(Allocator.Temp);
            foreach (var (xform, health, region, entity) in
                     SystemAPI.Query<RefRO<LocalTransform>, RefRO<Health>, RefRO<RegionTag>>()
                         .WithAll<PlayerTag>()
                         .WithEntityAccess())
            {
                if (health.ValueRO.Current <= 0f)
                    continue; // don't chase or strike a corpse
                playerEntities.Add(entity);
                playerPositions.Add(xform.ValueRO.Position);
                playerRegions.Add(region.ValueRO.Region);
            }

            // EB-1 fortress aggro: also snapshot live structures (Turret/Wall/Pylon AND the Fabricator all carry
            // Health since the DR-032 parity fix; the query keys on it). Snapshot ABOVE the early-return so Husks keep razing
            // the base even with every player dead/away (the locked 'push for structures' fork).
            var structureEntities = new NativeList<Entity>(Allocator.Temp);
            var structurePositions = new NativeList<float3>(Allocator.Temp);
            var structureRegions = new NativeList<byte>(Allocator.Temp);
            foreach (var (sx, sh, sr, se) in
                     SystemAPI.Query<RefRO<LocalTransform>, RefRO<Health>, RefRO<RegionTag>>()
                         .WithAll<PlacedStructure>()
                         .WithEntityAccess())
            {
                if (sh.ValueRO.Current <= 0f)
                    continue; // skip a structure already at 0 (pending destroy this tick)
                structureEntities.Add(se);
                structurePositions.Add(sx.ValueRO.Position);
                structureRegions.Add(sr.ValueRO.Region);
            }

            // END-1: the Engine Core is a FALLBACK target. When no living player/structure remains, undefended
            // Husks march on the base heart (PlotCenter) so the base can be overrun instead of the swarm idling.
            bool coreAlive = SystemAPI.HasSingleton<BaseAnchor>()
                             && SystemAPI.TryGetSingleton<CoreIntegrity>(out var coreInteg) && coreInteg.Current > 0;
            float3 corePos = coreAlive ? BaseGridMath.PlotCenter(SystemAPI.GetSingleton<BaseAnchor>()) : float3.zero;

            if (playerEntities.Length == 0 && structureEntities.Length == 0 && !coreAlive)
            {
                playerEntities.Dispose();
                playerPositions.Dispose();
                playerRegions.Dispose();
                structureEntities.Dispose();
                structurePositions.Dispose();
                structureRegions.Dispose();
                return;
            }

            float dt = SystemAPI.Time.DeltaTime;
            var serverTick = SystemAPI.GetSingleton<NetworkTime>().ServerTick;
            uint now = serverTick.TickIndexForValidTick;
            // Live feel knobs (MC-0): one read, guarded at use. Server-only — clients never simulate enemies.
            var tune = SystemAPI.TryGetSingleton<TuningConfig>(out var tcfg) ? tcfg : TuningConfig.Defaults();
            float structAggro = math.max(0f, tune.StructureAggroWeight);
            var ecb = new EntityCommandBuffer(Allocator.Temp);
            bool havePhysics = SystemAPI.TryGetSingleton<PhysicsWorldSingleton>(out var physics);
            uint envMask = SystemAPI.TryGetSingleton<WorldCollisionConfig>(out var worldCol) ? worldCol.EnvironmentMask : 0u;
            uint sweepMask = envMask | worldCol.StructureMask; // DR-042 C5: also collide enemies against player-built walls
            var envFilter = new CollisionFilter { BelongsTo = ~0u, CollidesWith = sweepMask, GroupIndex = 0 };
            bool sweep = havePhysics && sweepMask != 0u;
            const float SweepRadius = 0.5f; // collide-and-slide sphere radius for Husk movement

            foreach (var (xform, stats, cooldown, knockback, windup, region) in
                     SystemAPI.Query<RefRW<LocalTransform>, RefRO<EnemyStats>, RefRW<EnemyAttackCooldown>,
                             RefRW<KnockbackState>, RefRW<AttackWindup>, RefRO<RegionTag>>()
                         .WithAll<EnemyTag>().WithNone<LungeState, SpitterState>())
            {
                float3 pos = xform.ValueRO.Position;
                byte huskRegion = region.ValueRO.Region;
                bool huskCoreAlive = coreAlive && huskRegion == RegionId.Base;

                // Knockback overrides seek/strike for its window — EnemyAISystem stays the SOLE writer of Position.
                var kb = knockback.ValueRO;
                if (kb.UntilTick != 0)
                {
                    var kbTick = new NetworkTick(kb.UntilTick);
                    if (kbTick.IsValid && kbTick.IsNewerThan(serverTick))
                    {
                        float3 kpos = pos + new float3(kb.Dir.x, 0f, kb.Dir.y) * (kb.Speed * dt);
                        kpos.y = pos.y;
                        if (sweep)
                            kpos = SweptMove(in physics, pos, kpos, SweepRadius, envFilter);
                        xform.ValueRW.Position = kpos;
                        windup.ValueRW.WindUpUntilTick = 0; // a recoiling Husk does not wind up
                        continue; // recoiling: skip seek + strike this tick
                    }
                    knockback.ValueRW.UntilTick = 0; // window elapsed
                }

                // EB-1 fortress aggro: nearest of players (weight 1) + structures (StructureAggroWeight) — a wall/
                // turret is the preferred target unless a player is in the way (closer after weighting).
                EnemyAIMath.PickWeightedNearest(pos, playerPositions, playerRegions, structurePositions, structureRegions, huskRegion, structAggro, out bool tgtIsStruct, out int tgtIdx);
                if (tgtIdx < 0 && !huskCoreAlive)
                    continue; // no player/structure and no Core -> nothing to seek
                Entity targetEntity = tgtIdx < 0 ? Entity.Null
                    : (tgtIsStruct ? structureEntities[tgtIdx] : playerEntities[tgtIdx]);
                float3 targetPos = tgtIdx < 0 ? corePos
                    : (tgtIsStruct ? structurePositions[tgtIdx] : playerPositions[tgtIdx]);

                // Seek: stop just inside strike range so the Husk holds position to attack.
                float stopDistance = stats.ValueRO.AttackRange * 0.9f;
                float3 vel = EnemyAIMath.SeekVelocity(pos, targetPos, stats.ValueRO.MoveSpeed, stopDistance);
                float3 newPos = pos + vel * dt;
                newPos.y = pos.y; // hold the movement plane
                if (sweep)
                    newPos = SweptMove(in physics, pos, newPos, SweepRadius, envFilter);
                xform.ValueRW.Position = newPos;

                // Face the target (planar) for presentation.
                float3 toTarget = targetPos - pos;
                toTarget.y = 0f;
                if (math.lengthsq(toTarget) > 1e-6f)
                    xform.ValueRW.Rotation = quaternion.LookRotationSafe(math.normalize(toTarget), math.up());

                // Two-phase strike with a telegraph wind-up: commit a wind-up when first in-range + cooldown-ready,
                // then strike when it elapses. WindUpUntilTick is a [GhostField] so the client can cue the ~0.3s
                // tell; leaving range mid-windup cancels it. Tuning.AttackWindupTicks = 0/1 -> near-instant (legacy).
                bool inRange = EnemyAIMath.InAttackRange(pos, targetPos, stats.ValueRO.AttackRange);
                uint windRaw = windup.ValueRO.WindUpUntilTick;

                if (windRaw != 0)
                {
                    // B1 commitment: once inside the final ~30% of the wind-up the strike is COMMITTED — leaving
                    // range no longer cancels it (a last-instant step-back won't save you; dash i-frames or an early
                    // exit will). A committed swing the player dodged out of WHIFFS at elapse (still burns cooldown)
                    // -> the punish window, mirroring the Charger. Grunts (speed < player) can now actually land on a
                    // lingering player instead of being trivially kited (readable-but-fair).
                    var windTick = new NetworkTick(windRaw);
                    bool elapsed = !(windTick.IsValid && windTick.IsNewerThan(serverTick));
                    int remain = windTick.IsValid ? windTick.TicksSince(serverTick) : 0;
                    uint gTotal = (uint)math.max(1f, tune.GruntWindupTicks);
                    bool committed = remain > 0 && remain <= (int)(gTotal * 0.3f);
                    if (!elapsed)
                    {
                        if (!inRange && !committed)
                            windup.ValueRW.WindUpUntilTick = 0; // left range early -> cancel the wind-up
                    }
                    else
                    {
                        if (inRange && targetEntity != Entity.Null) ecb.AppendToBuffer(targetEntity, new DamageEvent
                        {
                            Amount = stats.ValueRO.AttackDamage,
                            SourceNetworkId = -1, // environment / Husk, not a player
                            SourceTick = TickUtil.NonZero(now),
                        });
                        uint cooldownTicks = (uint)math.max(1, stats.ValueRO.AttackCooldownTicks);
                        cooldown.ValueRW.NextAttackTick = TickUtil.NonZero(now + cooldownTicks);
                        windup.ValueRW.WindUpUntilTick = 0;
                    }
                }
                else if (inRange)
                {
                    uint nextRaw = cooldown.ValueRO.NextAttackTick;
                    bool ready = true;
                    if (nextRaw != 0)
                    {
                        var nextTick = new NetworkTick(nextRaw);
                        if (nextTick.IsValid && nextTick.IsNewerThan(serverTick))
                            ready = false;
                    }
                    if (ready)
                    {
                        uint windupTicks = (uint)math.max(1f, tune.GruntWindupTicks);
                        windup.ValueRW.WindUpUntilTick = TickUtil.NonZero(now + windupTicks);
                    }
                }
            }

            // --- Charger pass: a Husk variant baked with LungeState commits to a punishable fixed-direction lunge.
            // Component-presence is the discriminator; the Grunt pass above excludes these via .WithNone<LungeState>().
            // Charger feel knobs — live-tunable via TuningConfig (MC-0), guarded at the read site. Server-only
            // (clients never simulate Chargers); the >=1-tick floor avoids a degenerate instant/no-travel lunge.
            float ChargerLungeSpeed = math.max(0f, tune.ChargerLungeSpeed);        // units/s while lunging
            uint  ChargerLungeDurationTicks = (uint)math.max(1f, tune.ChargerLungeDurationTicks); // committed travel
            uint  ChargerWindupTicks = (uint)math.max(1f, tune.ChargerWindupTicks); // readable telegraph lead
            uint  ChargerWhiffStaggerTicks = (uint)math.max(1f, tune.ChargerWhiffStaggerTicks);   // punish window
            uint chargerWhiffsThisTick = 0;
            foreach (var (xform, stats, cooldown, knockback, windup, lunge, region) in
                     SystemAPI.Query<RefRW<LocalTransform>, RefRO<EnemyStats>, RefRW<EnemyAttackCooldown>,
                             RefRW<KnockbackState>, RefRW<AttackWindup>, RefRW<LungeState>, RefRO<RegionTag>>()
                         .WithAll<EnemyTag>().WithNone<SpitterState, BossState>())
            {
                float3 pos = xform.ValueRO.Position;
                byte cHuskRegion = region.ValueRO.Region;
                bool cHuskCoreAlive = coreAlive && cHuskRegion == RegionId.Base;

                // 1. Knockback wins (and cancels any in-flight lunge so Position keeps a single writer).
                var kb = knockback.ValueRO;
                if (kb.UntilTick != 0)
                {
                    var kbTick = new NetworkTick(kb.UntilTick);
                    if (kbTick.IsValid && kbTick.IsNewerThan(serverTick))
                    {
                        float3 kpos = pos + new float3(kb.Dir.x, 0f, kb.Dir.y) * (kb.Speed * dt);
                        kpos.y = pos.y;
                        if (sweep) kpos = SweptMove(in physics, pos, kpos, SweepRadius, envFilter);
                        xform.ValueRW.Position = kpos;
                        windup.ValueRW.WindUpUntilTick = 0;
                        lunge.ValueRW.UntilTick = 0;
                        continue;
                    }
                    knockback.ValueRW.UntilTick = 0;
                }

                // EB-1 fortress aggro: same weighted target selection as the Grunt pass (shared helper).
                EnemyAIMath.PickWeightedNearest(pos, playerPositions, playerRegions, structurePositions, structureRegions, cHuskRegion, structAggro, out bool cIsStruct, out int cIdx);
                if (cIdx < 0 && !cHuskCoreAlive)
                    continue;
                Entity cTargetEntity = cIdx < 0 ? Entity.Null
                    : (cIsStruct ? structureEntities[cIdx] : playerEntities[cIdx]);
                float3 cTargetPos = cIdx < 0 ? corePos
                    : (cIsStruct ? structurePositions[cIdx] : playerPositions[cIdx]);

                // 2. Lunge active: travel the locked direction; damage on contact, or stagger on a wall-stop whiff.
                var lg = lunge.ValueRO;
                if (lg.UntilTick != 0)
                {
                    var lgTick = new NetworkTick(lg.UntilTick);
                    if (lgTick.IsValid && lgTick.IsNewerThan(serverTick))
                    {
                        float3 intended = pos + new float3(lg.Dir.x, 0f, lg.Dir.y) * (lg.Speed * dt);
                        intended.y = pos.y;
                        float3 moved = sweep ? SweptMove(in physics, pos, intended, SweepRadius, envFilter) : intended;
                        xform.ValueRW.Position = moved;
                        if (math.lengthsq(lg.Dir) > 1e-6f)
                            xform.ValueRW.Rotation = quaternion.LookRotationSafe(new float3(lg.Dir.x, 0f, lg.Dir.y), math.up());

                        if (EnemyAIMath.InAttackRange(moved, cTargetPos, stats.ValueRO.AttackRange))
                        {
                            if (cTargetEntity != Entity.Null) ecb.AppendToBuffer(cTargetEntity, new DamageEvent
                            {
                                Amount = stats.ValueRO.AttackDamage,
                                SourceNetworkId = -1,
                                SourceTick = TickUtil.NonZero(now),
                            });
                            uint cdTicks = (uint)math.max(1, stats.ValueRO.AttackCooldownTicks);
                            cooldown.ValueRW.NextAttackTick = TickUtil.NonZero(now + cdTicks);
                            lunge.ValueRW.UntilTick = 0; // landed -> end the lunge
                        }
                        else
                        {
                            float intendedDist = math.distance(pos.xz, intended.xz);
                            float actualDist = math.distance(pos.xz, moved.xz);
                            if (intendedDist > 1e-4f && actualDist < intendedDist * 0.5f)
                            {
                                cooldown.ValueRW.NextAttackTick = TickUtil.NonZero(now + ChargerWhiffStaggerTicks);
                                lunge.ValueRW.UntilTick = 0; // wall-stop whiff -> stagger (the punish window)
                                chargerWhiffsThisTick++;
                                lunge.ValueRW.StaggerUntilTick = TickUtil.NonZero(now + ChargerWhiffStaggerTicks); // scoreable punish window
                            }
                        }
                        continue; // committed this tick
                    }

                    // Timer elapsed without landing -> overshoot whiff -> stagger, then seek this tick.
                    cooldown.ValueRW.NextAttackTick = TickUtil.NonZero(now + ChargerWhiffStaggerTicks);
                    lunge.ValueRW.UntilTick = 0;
                    chargerWhiffsThisTick++;
                    lunge.ValueRW.StaggerUntilTick = TickUtil.NonZero(now + ChargerWhiffStaggerTicks); // scoreable punish window
                }

                // 3. Seek + face (shared shape with the Grunt path). B3: a whiffed Charger is ROOTED during its
                // stagger punish window so the advertised punish reads (the player sees it stop). Facing still tracks.
                bool cStaggered = lunge.ValueRO.StaggerUntilTick != 0u
                                  && new NetworkTick(lunge.ValueRO.StaggerUntilTick).IsNewerThan(serverTick);
                if (!cStaggered)
                {
                    float cStop = stats.ValueRO.AttackRange * 0.9f;
                    float3 cvel = EnemyAIMath.SeekVelocity(pos, cTargetPos, stats.ValueRO.MoveSpeed, cStop);
                    float3 cNewPos = pos + cvel * dt; cNewPos.y = pos.y;
                    if (sweep) cNewPos = SweptMove(in physics, pos, cNewPos, SweepRadius, envFilter);
                    xform.ValueRW.Position = cNewPos;
                }
                float3 cToTarget = cTargetPos - pos; cToTarget.y = 0f;
                if (math.lengthsq(cToTarget) > 1e-6f)
                    xform.ValueRW.Rotation = quaternion.LookRotationSafe(math.normalize(cToTarget), math.up());

                // 4. Commit: a wind-up elapses -> LOCK the lunge direction + fire. NO cancel-on-leave-range — the
                //    whole point is the commit lands even if the player dodged out of range (the punishable tell).
                uint cWindRaw = windup.ValueRO.WindUpUntilTick;
                if (cWindRaw != 0)
                {
                    var cWindTick = new NetworkTick(cWindRaw);
                    if (!(cWindTick.IsValid && cWindTick.IsNewerThan(serverTick)))
                    {
                        float3 toT = cTargetPos - pos; toT.y = 0f;
                        float2 ldir = math.lengthsq(toT) > 1e-6f ? math.normalize(toT.xz) : new float2(0f, 1f);
                        lunge.ValueRW.Dir = ldir;
                        lunge.ValueRW.Speed = ChargerLungeSpeed;
                        lunge.ValueRW.UntilTick = TickUtil.NonZero(now + ChargerLungeDurationTicks);
                        windup.ValueRW.WindUpUntilTick = 0;
                    }
                }
                else
                {
                    bool cInRange = EnemyAIMath.InAttackRange(pos, cTargetPos, stats.ValueRO.AttackRange);
                    if (cInRange)
                    {
                        bool cReady = cooldown.ValueRO.NextAttackTick == 0
                                      || !new NetworkTick(cooldown.ValueRO.NextAttackTick).IsNewerThan(serverTick);
                        if (cReady)
                            windup.ValueRW.WindUpUntilTick = TickUtil.NonZero(now + ChargerWindupTicks);
                    }
                }
            }
            // --- Spitter pass: a Husk variant baked with SpitterState holds a RANGED range-band and fires a
            // telegraphed, dodgeable spit. Partitioned .WithAll<SpitterState>().WithNone<LungeState>() (and the Grunt
            // pass excludes SpitterState) so a Spitter is moved by EXACTLY this pass — the sole-Position-writer rule.
            bool haveSpit = SystemAPI.TryGetSingleton<SpitterProjectilePrefab>(out var spitCfg) && spitCfg.Prefab != Entity.Null;
            int liveSpits = m_EnemyProjectiles.CalculateEntityCount();
            LocalTransform spitBakedLt = default;
            EnemyProjectile spitBakedProj = default;
            if (haveSpit)
            {
                spitBakedLt = state.EntityManager.GetComponentData<LocalTransform>(spitCfg.Prefab);
                spitBakedProj = state.EntityManager.GetComponentData<EnemyProjectile>(spitCfg.Prefab);
            }
            foreach (var (xform, stats, knockback, windup, spitter, region) in
                     SystemAPI.Query<RefRW<LocalTransform>, RefRO<EnemyStats>, RefRW<KnockbackState>,
                             RefRW<AttackWindup>, RefRW<SpitterState>, RefRO<RegionTag>>()
                         .WithAll<EnemyTag, SpitterState>().WithNone<LungeState>())
            {
                float3 pos = xform.ValueRO.Position;
                byte sRegion = region.ValueRO.Region;
                bool sCoreAlive = coreAlive && sRegion == RegionId.Base;

                // 1. Knockback overrides everything (sole Position writer preserved).
                var kb = knockback.ValueRO;
                if (kb.UntilTick != 0)
                {
                    var kbTick = new NetworkTick(kb.UntilTick);
                    if (kbTick.IsValid && kbTick.IsNewerThan(serverTick))
                    {
                        float3 kpos = pos + new float3(kb.Dir.x, 0f, kb.Dir.y) * (kb.Speed * dt);
                        kpos.y = pos.y;
                        if (sweep) kpos = SweptMove(in physics, pos, kpos, SweepRadius, envFilter);
                        xform.ValueRW.Position = kpos;
                        windup.ValueRW.WindUpUntilTick = 0;
                        continue;
                    }
                    knockback.ValueRW.UntilTick = 0;
                }

                // 2. Target (region-scoped shared helper); Core fallback like the Grunt/Charger passes.
                EnemyAIMath.PickWeightedNearest(pos, playerPositions, playerRegions, structurePositions, structureRegions, sRegion, structAggro, out bool sIsStruct, out int sIdx);
                if (sIdx < 0 && !sCoreAlive)
                    continue;
                Entity sTargetEntity = sIdx < 0 ? Entity.Null
                    : (sIsStruct ? structureEntities[sIdx] : playerEntities[sIdx]);
                float3 sTargetPos = sIdx < 0 ? corePos
                    : (sIsStruct ? structurePositions[sIdx] : playerPositions[sIdx]);

                // 3. Range-band movement: advance if too far, retreat if too close, hold in-band. Face the target.
                var sp = spitter.ValueRO;
                // Once the player has closed inside CorneredRange the Spitter STANDS (no flee) + point-blanks — so a
                // melee player who commits can actually catch it (fixes the endless-kite complaint; the spit is dash-dodgeable).
                bool sCorneredMove = math.distance(pos.xz, sTargetPos.xz) <= sp.CorneredRange;
                float3 bandVel = sCorneredMove ? float3.zero
                    : EnemyAIMath.BandVelocity(pos, sTargetPos, stats.ValueRO.MoveSpeed, sp.PreferredRange, sp.RangeTolerance);
                float3 sNewPos = pos + bandVel * dt; sNewPos.y = pos.y;
                if (sweep) sNewPos = SweptMove(in physics, pos, sNewPos, SweepRadius, envFilter);
                xform.ValueRW.Position = sNewPos;
                float3 sToTarget = sTargetPos - pos; sToTarget.y = 0f;
                if (math.lengthsq(sToTarget) > 1e-6f)
                    xform.ValueRW.Rotation = quaternion.LookRotationSafe(math.normalize(sToTarget), math.up());

                // 4. Telegraphed shot: commit a wind-up (the dodge window) when the shot gate is ready; on elapse,
                //    spawn a spit toward the target. A cornered Spitter still fires (point-blank) — no safe corner.
                uint sWindRaw = windup.ValueRO.WindUpUntilTick;
                if (sWindRaw != 0)
                {
                    var sWindTick = new NetworkTick(sWindRaw);
                    if (!(sWindTick.IsValid && sWindTick.IsNewerThan(serverTick)))
                    {
                        float2 dir2 = math.lengthsq(sToTarget) > 1e-6f ? math.normalize(sToTarget.xz) : new float2(0f, 1f);
                        if (haveSpit && liveSpits < math.max(1, spitCfg.MaxLiveProjectiles))
                        {
                            float3 spawnPos = pos + new float3(dir2.x, 0f, dir2.y) * 0.8f;
                            spawnPos.y = pos.y;
                            var spit = ecb.Instantiate(spitCfg.Prefab);
                            ecb.SetComponent(spit, spitBakedLt.WithPosition(spawnPos)); // preserve baked [GhostField] Scale
                            ecb.SetComponent(spit, new EnemyProjectile
                            {
                                Direction = dir2,
                                Speed = sp.ProjectileSpeed,
                                Damage = stats.ValueRO.AttackDamage,
                                Range = spitBakedProj.Range,
                                DistanceTravelled = 0f,
                                LastStep = 0f,
                                Region = sRegion,
                            });
                            ecb.AddComponent(spit, new RegionTag { Region = sRegion }); // relevancy (the spit prefab bakes none)
                            liveSpits++;
                            uint shotCd = (uint)math.max(1, stats.ValueRO.AttackCooldownTicks);
                            spitter.ValueRW.NextShotTick = TickUtil.NonZero(now + shotCd);
                        }
                        else
                        {
                            // Over the concurrent cap (or no prefab wired): soft-fail — short retry, no full cooldown burn.
                            spitter.ValueRW.NextShotTick = TickUtil.NonZero(now + 8u);
                        }
                        windup.ValueRW.WindUpUntilTick = 0;
                    }
                }
                else
                {
                    bool sReady = sp.NextShotTick == 0 || !new NetworkTick(sp.NextShotTick).IsNewerThan(serverTick);
                    // In-band gate (DR-041): telegraph + fire ONLY when holding the preferred band, OR when the target has
                    // closed inside CorneredRange (point-blank, no retreat room). While ADVANCING from too far OR
                    // RETREATING from a too-close target it must NOT fire — that IS the hold-range "reposition" question.
                    float sDist = math.length(sToTarget);
                    bool sInBand = math.abs(sDist - sp.PreferredRange) <= sp.RangeTolerance;
                    bool sCornered = sDist <= sp.CorneredRange;
                    if (sReady && (sInBand || sCornered) && (sTargetEntity != Entity.Null || sCoreAlive))
                    {
                        uint wTicks = (uint)math.max(1, sp.WindupTicks);
                        windup.ValueRW.WindUpUntilTick = TickUtil.NonZero(now + wTicks);
                    }
                }
            }


            // Slice 1 (Feature D): derive the replicated IsLunging cue ONCE per tick from the end-of-tick LungeState
            // (single point, idempotent — mirrors PlayerDeathStateSystem deriving Dead from Health). .WithPresent so a
            // Charger whose bit is currently DISABLED is still visited (Entities default-excludes disabled enableables).
            foreach (var (lunge, isLunging) in
                     SystemAPI.Query<RefRO<LungeState>, EnabledRefRW<IsLunging>>()
                         .WithAll<EnemyTag>().WithPresent<IsLunging>())
            {
                isLunging.ValueRW = lunge.ValueRO.UntilTick != 0u; // lunging iff a committed lunge is live this tick
            }

            if (chargerWhiffsThisTick != 0 && SystemAPI.HasSingleton<DevTelemetry>())
                SystemAPI.GetSingletonRW<DevTelemetry>().ValueRW.ChargerWhiffWindowsOpened += chargerWhiffsThisTick;

            ecb.Playback(state.EntityManager);

            ecb.Dispose();
            playerEntities.Dispose();
            playerPositions.Dispose();
            playerRegions.Dispose();
            structureEntities.Dispose();
            structurePositions.Dispose();
            structureRegions.Dispose();
        }

        // Swept collide-and-slide for server-authoritative enemy movement — delegates to the shared
        // EnemyMoveUtil.SweptMove (extracted so BossAISystem reuses ONE collide-and-slide impl; a fix reaches both).
        // Kept as a private wrapper so this file's many call sites read unchanged.
        static float3 SweptMove(in PhysicsWorldSingleton physics, float3 from, float3 to, float radius, CollisionFilter filter)
            => EnemyMoveUtil.SweptMove(in physics, from, to, radius, filter);
    }
}