// In-browser 3D preview for STL / 3MF / OBJ files, loaded as an ES module.
import * as THREE from 'three';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
import { STLLoader } from 'three/addons/loaders/STLLoader.js';
import { OBJLoader } from 'three/addons/loaders/OBJLoader.js';
import { ThreeMFLoader } from 'three/addons/loaders/3MFLoader.js';
import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';

// Formats the renderer can draw directly. 3MF is rendered via server-converted
// GLB (see RENDERABLE for what the app treats as previewable input).
const SUPPORTED = ['stl', 'obj', 'glb'];
const RENDERABLE = ['stl', '3mf', 'obj'];
let active = null; // { renderer, controls, rafId }

function dispose() {
  if (!active) return;
  cancelAnimationFrame(active.rafId);
  active.controls.dispose();
  active.renderer.dispose();
  const el = active.renderer.domElement;
  if (el.parentNode) el.parentNode.removeChild(el);
  active = null;
}

function message(container, text) {
  container.innerHTML = `<div class="viewer-msg">${text}</div>`;
}

// When 3D rendering isn't possible (e.g. Bambu/MakerWorld 3MF project files that
// the loader can't parse), show the model's preview image instead of an error.
function showFallback(container, image, text) {
  if (image) {
    container.innerHTML =
      `<div class="viewer-fallback"><img src="${image}" alt=""><span>${text}</span></div>`;
  } else {
    message(container, text);
  }
}

async function loadObject(url, format) {
  if (format === 'stl') {
    const geometry = await new STLLoader().loadAsync(url);
    geometry.computeVertexNormals();
    const material = new THREE.MeshStandardMaterial({ color: 0xc4cad6, metalness: 0.15, roughness: 0.65 });
    const mesh = new THREE.Mesh(geometry, material);
    mesh.rotation.x = -Math.PI / 2; // STL is typically Z-up; sit it flat
    return mesh;
  }
  if (format === 'obj') return new OBJLoader().loadAsync(url);
  if (format === '3mf') return new ThreeMFLoader().loadAsync(url);
  if (format === 'glb') {
    const gltf = await new GLTFLoader().loadAsync(url);
    gltf.scene.rotation.x = -Math.PI / 2; // 3MF/trimesh is Z-up; sit it upright
    return gltf.scene;
  }
  throw new Error(`Unsupported format ${format}`);
}

async function render(container, url, format, opts = {}) {
  dispose();
  container.innerHTML = '';
  if (!SUPPORTED.includes(format)) {
    showFallback(container, opts.fallbackImage, `No 3D preview for .${format} files.`);
    return;
  }

  const width = container.clientWidth || 600;
  const height = container.clientHeight || 420;

  const scene = new THREE.Scene();
  const camera = new THREE.PerspectiveCamera(45, width / height, 0.1, 1e6);
  const renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true });
  renderer.setPixelRatio(window.devicePixelRatio);
  renderer.setSize(width, height);
  container.appendChild(renderer.domElement);

  scene.add(new THREE.AmbientLight(0xffffff, 0.65));
  const key = new THREE.DirectionalLight(0xffffff, 0.85); key.position.set(1, 1, 1); scene.add(key);
  const fill = new THREE.DirectionalLight(0xffffff, 0.35); fill.position.set(-1, 0.5, -1); scene.add(fill);

  const controls = new OrbitControls(camera, renderer.domElement);
  controls.enableDamping = true;

  let object;
  try {
    object = await loadObject(url, format);
  } catch (err) {
    renderer.dispose();
    renderer.forceContextLoss();
    if (renderer.domElement.parentNode) renderer.domElement.parentNode.removeChild(renderer.domElement);
    const note = format === '3mf'
      ? 'Interactive 3D isn’t supported for this 3MF (Bambu/MakerWorld project file).'
      : 'This file couldn’t be rendered in 3D.';
    showFallback(container, opts.fallbackImage, note);
    return;
  }

  // Center the object and frame the camera around it.
  const box = new THREE.Box3().setFromObject(object);
  const size = box.getSize(new THREE.Vector3());
  const center = box.getCenter(new THREE.Vector3());
  object.position.sub(center);
  scene.add(object);

  const maxDim = Math.max(size.x, size.y, size.z) || 1;
  camera.position.set(maxDim * 1.4, maxDim * 1.1, maxDim * 1.8);
  camera.near = maxDim / 100;
  camera.far = maxDim * 100;
  camera.updateProjectionMatrix();
  controls.target.set(0, 0, 0);
  controls.update();

  active = { renderer, controls, rafId: 0 };
  const loop = () => {
    if (!active) return;
    active.rafId = requestAnimationFrame(loop);
    controls.update();
    renderer.render(scene, camera);
  };
  loop();
}

// Render a model once to an offscreen canvas and return a PNG data URL.
// Used to generate card thumbnails. Transparent background so it composites
// over the card surface.
async function snapshot(url, format, size = 512) {
  if (!SUPPORTED.includes(format)) return null;

  const renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true, preserveDrawingBuffer: true });
  renderer.setSize(size, size);
  renderer.setClearColor(0x000000, 0);

  const scene = new THREE.Scene();
  const camera = new THREE.PerspectiveCamera(45, 1, 0.1, 1e6);
  scene.add(new THREE.AmbientLight(0xffffff, 0.65));
  const key = new THREE.DirectionalLight(0xffffff, 0.85); key.position.set(1, 1, 1); scene.add(key);
  const fill = new THREE.DirectionalLight(0xffffff, 0.35); fill.position.set(-1, 0.5, -1); scene.add(fill);

  try {
    const object = await loadObject(url, format);
    const box = new THREE.Box3().setFromObject(object);
    const dim = box.getSize(new THREE.Vector3());
    const center = box.getCenter(new THREE.Vector3());
    object.position.sub(center);
    scene.add(object);

    const maxDim = Math.max(dim.x, dim.y, dim.z) || 1;
    camera.position.set(maxDim * 1.3, maxDim * 1.0, maxDim * 1.7);
    camera.near = maxDim / 100;
    camera.far = maxDim * 100;
    camera.lookAt(0, 0, 0);
    camera.updateProjectionMatrix();

    renderer.render(scene, camera);
    return renderer.domElement.toDataURL('image/png');
  } finally {
    renderer.dispose();
    renderer.forceContextLoss();
  }
}

window.ModelViewer = { render, dispose, snapshot, SUPPORTED, RENDERABLE };