/**
 * @title OBJ Loader Use Model Mesh
 * @category Mesh
 * @thumbnail https://mdn.alipayobjects.com/merchant_appfe/afts/img/A*ZnBlT4UNh0IAAAAAAAAAAAAADiR2AQ/original
 */
import { OrbitControl } from "@galacean/engine-toolkit-controls";
import {
  BlinnPhongMaterial,
  Camera,
  Color,
  DirectLight,
  MeshRenderer,
  MeshTopology,
  ModelMesh,
  Vector3,
  WebGLEngine,
} from "@galacean/engine";

WebGLEngine.create({ canvas: "canvas" }).then((engine) => {
  engine.canvas.resizeByClientSize();
  const scene = engine.sceneManager.activeScene;
  const rootEntity = scene.createRootEntity();

  // init camera
  const cameraEntity = rootEntity.createChild("camera");
  cameraEntity.addComponent(Camera);
  cameraEntity.addComponent(OrbitControl);
  cameraEntity.transform.setPosition(0.5, 0.5, 0.5);
  cameraEntity.transform.lookAt(new Vector3(0, 0, 0));

  // init light
  rootEntity.addComponent(DirectLight);

  fetch(
    "https://gw.alipayobjects.com/os/bmw-prod/b885a803-5315-44f0-af54-6787ec47ed1b.obj"
  )
    .then((res) => res.text())
    .then((objText) => {
      const lines = objText.split(/\n/);
      const positions = [];
      const indices: number[] = [];
      lines
        .map((lineText) => lineText.split(" "))
        .forEach((parseTexts) => {
          if (parseTexts[0] === "v") {
            positions.push(
              new Vector3(
                parseFloat(parseTexts[1]),
                parseFloat(parseTexts[2]),
                parseFloat(parseTexts[3])
              )
            );
          } else if (parseTexts[0] === "f") {
            indices.push(
              parseInt(parseTexts[1]) - 1,
              parseInt(parseTexts[2]) - 1,
              parseInt(parseTexts[3]) - 1
            );
          }
        });

      const mesh = new ModelMesh(engine);
      mesh.setPositions(positions);
      mesh.setIndices(Uint16Array.from(indices));
      mesh.addSubMesh(0, indices.length, MeshTopology.Triangles);
      mesh.uploadData(false);

      // init cube
      const cubeEntity = rootEntity.createChild("cube");
      const renderer = cubeEntity.addComponent(MeshRenderer);
      renderer.mesh = mesh;
      const material = new BlinnPhongMaterial(engine);
      material.baseColor = new Color(1, 0.25, 0.25, 1);
      renderer.setMaterial(material);
    });

  engine.run();
});