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

namespace HappyForest.Prototypen
{
    // Bewegt alle Pillen und lässt sie an den (aus den "Wall"-Objekten berechneten)
    // Feld-Grenzen abprallen. Läuft komplett als Burst-kompilierter Parallel-Job.
    [BurstCompile]
    public partial struct PilleMovementSystem : ISystem
    {
        public void OnCreate(ref SystemState state)
        {
            state.RequireForUpdate<PilleSimulationConfig>();
        }

        [BurstCompile]
        public void OnUpdate(ref SystemState state)
        {
            var config = SystemAPI.GetSingleton<PilleSimulationConfig>();
            float deltaTime = SystemAPI.Time.DeltaTime;

            var job = new MoveAndBounceJob
            {
                DeltaTime = deltaTime,
                BoundsMin = config.BoundsMin,
                BoundsMax = config.BoundsMax,
                PlayHeight = config.PlayHeight
            };

            state.Dependency = job.ScheduleParallel(state.Dependency);
        }
    }

    [BurstCompile]
    public partial struct MoveAndBounceJob : IJobEntity
    {
        public float DeltaTime;
        public float3 BoundsMin;
        public float3 BoundsMax;
        public float PlayHeight;

        void Execute(ref LocalTransform transform, ref PilleComponent pille)
        {
            if (math.lengthsq(pille.Velocity) < 0.0001f)
                pille.Velocity = new float3(1f, 0f, 0f);

            float3 pos = transform.Position + pille.Velocity * pille.Speed * DeltaTime;

            if (pos.x < BoundsMin.x || pos.x > BoundsMax.x)
            {
                pille.Velocity.x *= -1f;
                pos.x = math.clamp(pos.x, BoundsMin.x, BoundsMax.x);
            }

            if (pos.z < BoundsMin.z || pos.z > BoundsMax.z)
            {
                pille.Velocity.z *= -1f;
                pos.z = math.clamp(pos.z, BoundsMin.z, BoundsMax.z);
            }

            pos.y = PlayHeight;
            transform.Position = pos;
        }
    }
}