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

namespace ProjectM.Simulation
{
    /// <summary>
    /// Predicted aim/facing: writes <see cref="PlayerFacing"/> from twin-stick Aim, falling back to
    /// the movement direction when Aim is zero (controller-first directional aim). Also turns the
    /// ghost transform toward the facing direction for top-down presentation. When there is no input
    /// this tick the previous facing is held. Deterministic (pure math); filtered to
    /// <see cref="Simulate"/> so it runs only for predicted ghosts.
    /// </summary>
    [UpdateInGroup(typeof(PredictedSimulationSystemGroup))]
    [BurstCompile]
    public partial struct PlayerAimSystem : ISystem
    {
        [BurstCompile]
        public void OnUpdate(ref SystemState state)
        {
            foreach (var (facing, transform, input) in
                     SystemAPI.Query<RefRW<PlayerFacing>, RefRW<LocalTransform>, RefRO<PlayerInput>>()
                         .WithAll<Simulate>())
            {
                float2 aim = input.ValueRO.Aim;
                if (math.lengthsq(aim) < 1e-6f)
                    aim = input.ValueRO.Move; // fall back to movement heading
                if (math.lengthsq(aim) < 1e-6f)
                    continue; // no input this tick: keep last facing

                aim = math.normalize(aim);
                facing.ValueRW.Direction = aim;

                float3 forward = new float3(aim.x, 0f, aim.y);
                transform.ValueRW.Rotation = quaternion.LookRotationSafe(forward, math.up());
            }
        }
    }
}