using Unity.Burst;
using Unity.Entities;
using Unity.Mathematics;
using Unity.NetCode;
using Unity.Transforms;

namespace ProjectM.Simulation
{
    /// <summary>
    /// Predicted body facing — the Shape-of-Dreams model (07-15): while MOVING the body turns toward the
    /// movement direction; during a CAST window (melee swing, any non-Movement socket fire window) it turns
    /// toward the aim at a snappier rate; idle holds the last facing. The cursor is never passively tracked.
    /// PlayerFacing is presentation/body-yaw ONLY — every gameplay fire direction reads
    /// FacingMath.ResolveAim(PlayerInput.Aim, facing) at its own site (AbilityFireSystem, MeleeComboSystem).
    /// The rate-limited turn is an incremental integrator over the snapshot-restored [GhostField]
    /// PlayerFacing — NO IsFirstTimeFullyPredictingTick guard; it must re-integrate on EVERY predicted pass
    /// so rollback re-simulation converges (gating it freezes facing at the rollback-tick value and diverges
    /// from the server). Partial-tick writes are discarded by the prediction restore before the next full
    /// tick. [UpdateAfter(MeleeComboSystem)] is a hygiene pin (sorter tie-breaks are deterministic and
    /// cross-world-identical) so the melee cast window opens the same tick the swing starts; socket windows
    /// open 1 tick late by construction (AbilityFireSystem stamps AFTER this system) — cosmetic-only.
    /// Turn rates: locomotion = EffectiveCharacterStats.TurnRateRadiansPerSec; cast = a const — both
    /// dev-overridable via TuningKnob.TurnRateDeg / CastTurnRateDeg (0 = no override; Defaults() fallback
    /// keeps release worlds server==client). Deterministic (pure math, fixed-step dt); Simulate-filtered.
    /// </summary>
    [UpdateInGroup(typeof(PredictedSimulationSystemGroup))]
    [UpdateAfter(typeof(MeleeComboSystem))]
    [BurstCompile]
    public partial struct PlayerAimSystem : ISystem
    {
        /// <summary>Cast-window turn rate (rad/s): snappy turn toward the aim mid-swing/fire (1080 deg/s).</summary>
        public const float DefaultCastTurnRateRadiansPerSec = 18.8495559f;

        /// <summary>Ticks facing stays aimed after a swing/fire starts (~0.22s @60Hz — matches the anim pulse
        /// k_AttackAnimTicks so body yaw and the swing animation agree).</summary>
        public const uint CastFacingTicks = 13;

        [BurstCompile]
        public void OnUpdate(ref SystemState state)
        {
            float dt = SystemAPI.Time.DeltaTime;
            NetworkTick serverTick = SystemAPI.TryGetSingleton<NetworkTime>(out var nt) ? nt.ServerTick : default;
            var abilityDb = SystemAPI.TryGetSingleton<AbilityDatabase>(out var adbSingleton) ? adbSingleton.Value : default;
            var tc = SystemAPI.TryGetSingleton<TuningConfig>(out var tcs) ? tcs : TuningConfig.Defaults();
            var effSocketLookup = SystemAPI.GetBufferLookup<EffectiveSocketStats>(true);

            foreach (var (facing, transform, input, stats, melee, socketCd, sockets, entity) in
                     SystemAPI.Query<RefRW<PlayerFacing>, RefRW<LocalTransform>, RefRO<PlayerInput>,
                                     RefRO<EffectiveCharacterStats>, RefRO<MeleeCombo>, RefRO<SocketCooldown>,
                                     DynamicBuffer<AbilitySocket>>()
                         .WithAll<Simulate>().WithDisabled<Dead>().WithEntityAccess())
            {
                // Cast window: melee swing first (cheap), else any non-Movement socket fire window
                // (TickWindowMath skips Movement sockets — a blink is a dodge, never a cast).
                bool castActive = TickWindowMath.SwingActive(melee.ValueRO, serverTick, CastFacingTicks);
                if (!castActive && effSocketLookup.HasBuffer(entity))
                    TickWindowMath.SocketFireAndCone(socketCd.ValueRO, sockets, effSocketLookup[entity],
                        abilityDb, serverTick, CastFacingTicks, out castActive, out _);

                if (!FacingMath.SelectTarget(castActive, input.ValueRO.Aim, input.ValueRO.Move, out float2 target))
                    continue; // no target this tick: keep last facing

                float rate = castActive
                    ? (tc.CastTurnRateDeg > 0f ? math.radians(tc.CastTurnRateDeg) : DefaultCastTurnRateRadiansPerSec)
                    : (tc.TurnRateDeg > 0f ? math.radians(tc.TurnRateDeg) : stats.ValueRO.TurnRateRadiansPerSec);

                float2 dir = FacingMath.RotateToward(facing.ValueRO.Direction, target, rate * dt);
                facing.ValueRW.Direction = dir;
                transform.ValueRW.Rotation = quaternion.LookRotationSafe(new float3(dir.x, 0f, dir.y), math.up());
            }
        }
    }
}