using Unity.Entities;
using Unity.Mathematics;
using Unity.Transforms2D;
using UnityEngine;
using Unity.Jobs;

//Just gives the animals a little movement as an example
public class EntityMovementSystem : JobComponentSystem
{
	[Inject] private Data data;

	[ComputeJobOptimization]
    struct PositionJob : IJobProcessComponentData<Position2D>
    {
        public float dt;

        public void Execute(ref Position2D position)
        {
			float wobbleX = Mathf.PerlinNoise(position.Value.x, position.Value.y) - 0.5f;
			float wobbleY = Mathf.PerlinNoise(position.Value.y, position.Value.x) - 0.5f;
			position.Value += dt * new float2(wobbleX, wobbleY);
        }
    }

	// protected override void OnUpdate()
	// {
	// 	var dt = Time.deltaTime;

	// 	for (var index = 0; index < data.Length; ++index)
	// 	{
	// 		var position = data.Position[index].Value;
	// 		var heading = data.Heading[index].Value;

	// 		float wobbleX = Mathf.PerlinNoise(position.x, position.y) - 0.5f;
	// 		float wobbleY = Mathf.PerlinNoise(position.y, position.x) - 0.5f;
	// 		position += dt * new float2(wobbleX, wobbleY);

	// 		data.Position[index] = new Position2D {Value = position};
	// 		data.Heading[index] = new Heading2D {Value = heading};
	// 	}
	// }

	 protected override JobHandle OnUpdate(JobHandle inputDeps)
    {
        var job = new PositionJob() { dt = Time.deltaTime };
        return job.Schedule(this, 64, inputDeps);
    }

	public struct Data
	{
		public int Length;
		public ComponentDataArray<Position2D> Position;
		public ComponentDataArray<Heading2D> Heading;
	}
}