import * as THREE from 'three';

// https://discourse.threejs.org/t/solved-create-a-spring/45135/9
class Spring extends THREE.Mesh{
  constructor(radius, turns, segmentsPerTurn, height, growth, material){
    let g = new THREE.CylinderGeometry(0.005, 0.005, 1, 16, segmentsPerTurn * turns).translate(0, 0.5, 0).rotateX(Math.PI * 0.5);
    let initPos = g.attributes.position.clone();
    super(g, material);
    this.radius = radius;
    this.turns = turns;
    this.segmentsPerTurn = segmentsPerTurn;
    this.height = height;
    this.growth = growth;
    
    this.update = () => {
      let _n = new THREE.Vector3(0, 1, 0), _v3 = new THREE.Vector3(), _s = new THREE.Vector3();

      let pos = g.attributes.position;
      for(let i = 0; i < initPos.count; i++){
        let ratio = initPos.getZ(i) * this.growth;
        let angle = this.turns * Math.PI * 2 * ratio;
        _v3.fromBufferAttribute(initPos, i).setZ(0);
        _v3.applyAxisAngle(_n, angle + Math.PI * 0.5);
        _v3.add(_s.setFromCylindricalCoords(this.radius, angle, this.height * ratio));
        pos.setXYZ(i, ... _v3);
      }
      g.computeVertexNormals();
      pos.needsUpdate = true;
      
    }
  }
}

export { Spring };