import {
  BackSide,
  BoxGeometry,
  InstancedMesh,
  Mesh,
  MeshLambertMaterial,
  MeshStandardMaterial,
  PointLight,
  Scene,
  Object3D,
} from "three";

/**
 * This class represents a scene with a basic room setup that can be used as
 * input for {@link PMREMGenerator#fromScene}. The resulting PMREM represents the room's
 * lighting and can be used for Image Based Lighting by assigning it to {@link Scene#environment}
 * or directly as an environment map to PBR materials.
 *
 * The implementation is based on the [EnvironmentScene](https://github.com/google/model-viewer/blob/master/packages/model-viewer/src/three-components/EnvironmentScene.ts)
 * component from the `model-viewer` project.
 *
 * ```js
 * const environment = new RoomEnvironment();
 * const pmremGenerator = new THREE.PMREMGenerator( renderer );
 *
 * const envMap = pmremGenerator.fromScene( environment ).texture;
 * scene.environment = envMap;
 * ```
 *
 * @augments Scene
 * @three_import import { RoomEnvironment } from 'three/addons/environments/RoomEnvironment.js';
 */
class RoomEnvironment extends Scene {
  constructor() {
    super();

    const geometry = new BoxGeometry();
    geometry.deleteAttribute("uv");

    const roomMaterial = new MeshStandardMaterial({ side: BackSide });
    const boxMaterial = new MeshStandardMaterial();

    const mainLight = new PointLight(0xffffff, 900, 28, 2);
    mainLight.position.set(0.418, 16.199, 0.3);
    this.add(mainLight);

    const room = new Mesh(geometry, roomMaterial);
    room.position.set(-0.757, 13.219, 0.717);
    room.scale.set(31.713, 28.305, 28.591);
    this.add(room);

    const boxes = new InstancedMesh(geometry, boxMaterial, 6);
    const transform = new Object3D();

    // box1
    transform.position.set(-10.906, 2.009, 1.846);
    transform.rotation.set(0, -0.195, 0);
    transform.scale.set(2.328, 7.905, 4.651);
    transform.updateMatrix();
    boxes.setMatrixAt(0, transform.matrix);

    // box2
    transform.position.set(-5.607, -0.754, -0.758);
    transform.rotation.set(0, 0.994, 0);
    transform.scale.set(1.97, 1.534, 3.955);
    transform.updateMatrix();
    boxes.setMatrixAt(1, transform.matrix);

    // box3
    transform.position.set(6.167, 0.857, 7.803);
    transform.rotation.set(0, 0.561, 0);
    transform.scale.set(3.927, 6.285, 3.687);
    transform.updateMatrix();
    boxes.setMatrixAt(2, transform.matrix);

    // box4
    transform.position.set(-2.017, 0.018, 6.124);
    transform.rotation.set(0, 0.333, 0);
    transform.scale.set(2.002, 4.566, 2.064);
    transform.updateMatrix();
    boxes.setMatrixAt(3, transform.matrix);

    // box5
    transform.position.set(2.291, -0.756, -2.621);
    transform.rotation.set(0, -0.286, 0);
    transform.scale.set(1.546, 1.552, 1.496);
    transform.updateMatrix();
    boxes.setMatrixAt(4, transform.matrix);

    // box6
    transform.position.set(-2.193, -0.369, -5.547);
    transform.rotation.set(0, 0.516, 0);
    transform.scale.set(3.875, 3.487, 2.986);
    transform.updateMatrix();
    boxes.setMatrixAt(5, transform.matrix);

    this.add(boxes);

    // -x right
    const light1 = new Mesh(geometry, createAreaLightMaterial(50));
    light1.position.set(-16.116, 14.37, 8.208);
    light1.scale.set(0.1, 2.428, 2.739);
    this.add(light1);

    // -x left
    const light2 = new Mesh(geometry, createAreaLightMaterial(50));
    light2.position.set(-16.109, 18.021, -8.207);
    light2.scale.set(0.1, 2.425, 2.751);
    this.add(light2);

    // +x
    const light3 = new Mesh(geometry, createAreaLightMaterial(17));
    light3.position.set(14.904, 12.198, -1.832);
    light3.scale.set(0.15, 4.265, 6.331);
    this.add(light3);

    // +z
    const light4 = new Mesh(geometry, createAreaLightMaterial(43));
    light4.position.set(-0.462, 8.89, 14.52);
    light4.scale.set(4.38, 5.441, 0.088);
    this.add(light4);

    // -z
    const light5 = new Mesh(geometry, createAreaLightMaterial(20));
    light5.position.set(3.235, 11.486, -12.541);
    light5.scale.set(2.5, 2.0, 0.1);
    this.add(light5);

    // +y
    const light6 = new Mesh(geometry, createAreaLightMaterial(100));
    light6.position.set(0.0, 20.0, 0.0);
    light6.scale.set(1.0, 0.1, 1.0);
    this.add(light6);
  }

  /**
   * Frees internal resources. This method should be called
   * when the environment is no longer required.
   */
  dispose() {
    const resources = new Set();

    this.traverse((object) => {
      if (object.isMesh) {
        resources.add(object.geometry);
        resources.add(object.material);
      }
    });

    for (const resource of resources) {
      resource.dispose();
    }
  }
}

function createAreaLightMaterial(intensity) {
  // create an emissive-only material. see #31348
  const material = new MeshLambertMaterial({
    color: 0x000000,
    emissive: 0xffffff,
    emissiveIntensity: intensity,
  });

  return material;
}

export { RoomEnvironment };