const alpha = 5;
const beta = -10;
const delta = -0.38;

const dt = 0.001;

const particlesNumber = 100000;


let canvasWidth;
let canvasHeight;
let midX;
let midY;

const far = 2000;

const scene = new THREE.Scene();

const system = new THREE.Object3D();
scene.add(system);

const renderer = new THREE.WebGLRenderer({antialias: true});
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.setClearColor(0xfafafa);
renderer.setPixelRatio(window.devicePixelRatio);
renderer.shadowMap.enabled = false;

const light = new THREE.DirectionalLight(0xffffff);
light.position.set(0.5, 100, 0);
scene.add(light);
scene.fog = new THREE.Fog(0x000000, 100, 1);

// camera
const camera = new THREE.PerspectiveCamera(-80, window.innerWidth / window.innerHeight, 1, far);
camera.position.set(-60, 630, 970);

// controller
const controls = new THREE.OrbitControls(camera, renderer.domElement);
controls.enableDamping = true;
controls.dampingFactor = 0.9;
controls.enableZoom = true;
controls.minDistance = 100;
// controls.maxDistance = 1400;

const summon = () => {
  canvasWidth = window.innerWidth;
  canvasHeight = window.innerHeight;
  midX = canvasWidth >> 1;
  midY = canvasHeight >> 1;
};

const init = () => {
  const scale = 10;

  let x = 0.4;
  let y = 0.3;
  let z = 0.1;

  let maxHeight = 0;
  let maxDepth = 0;
  const points = [];

  // calculate points for attractor and push them in the geometry
  for (let i = 0; i < particlesNumber; i++) {
let x1 = alpha * x - y * z;
    let y1 = beta * y + x * z;
    let z1 = delta * z + (x * y) / 3;

    x1 *= dt;
    y1 *= dt;
    z1 *= dt;

    x += x1;
    y += y1;
    z += z1;
    const vector = new THREE.Vector3(x * scale, y * scale, z * scale);
    points.push(vector);
  }

  const spline = new THREE.CatmullRomCurve3(points);
  spline.type = 'catmullrom';
  spline.tension = 0;

  const extrudeSettings = {
    steps: particlesNumber / 2,
    bevelEnabled: false,
    extrudePath: spline
  };

  const shaped = [];
  const width = 4;

  shaped.push(new THREE.Vector2(0, 0));
  shaped.push(new THREE.Vector2(width, 0));
  shaped.push(new THREE.Vector2(width, width));
  shaped.push(new THREE.Vector2(0, width));

  const shape = new THREE.Shape(shaped);
  const geometry = new THREE.ExtrudeGeometry(shape, extrudeSettings);
  const material = new THREE.MeshLambertMaterial({
    color: 0xffffff,
    shading: THREE.FlatShading,
    vertexColors: THREE.VertexColors
  });

  const mesh = new THREE.Mesh(geometry, material);
  mesh.castShadow = true;
  mesh.receiveShadow = false;
  system.add(mesh);
};

const boot = () => {
  renderer.render(scene, camera);
  requestAnimationFrame(boot);
};

window.addEventListener('resize', () => {
  summon();
  camera.aspect = canvasWidth / canvasHeight;
  camera.updateProjectionMatrix();
  renderer.setSize(canvasWidth, canvasHeight);
});

summon();
init();
boot();

document.body.appendChild(renderer.domElement);