// viewer.js
// Modern PlayCanvas GSplat/SOGS Viewer
let pc;            
export let app = null;
let cameraEntity = null;
let modelEntity = null;
let viewerInitialized = false;
let resizeObserver = null;

let chosenCameraX, chosenCameraY, chosenCameraZ;
let minZoom, maxZoom, minAngle, maxAngle, minAzimuth, maxAzimuth, minPivotY, minY;
let modelX, modelY, modelZ, modelScale, modelRotationX, modelRotationY, modelRotationZ;

// Main SOGS meta.json URL
let sogsUrl;

// == MAIN ENTRY POINT ==
export async function initializeViewer(config, instanceId) {
  if (viewerInitialized) return;

  // --- PlayCanvas: dynamically import from esm.run ---
  if (!pc) {
    try {
      pc = await import("https://esm.run/playcanvas");
      window.pc = pc; // for debugging
    } catch (e) {
      alert('Failed to load PlayCanvas engine from esm.run: ' + e);
      return;
    }
  }

  // -- Device type detection --
  const isIOS = /iPad|iPhone|iPod/.test(navigator.userAgent);
  const isMobile = isIOS || /Android/i.test(navigator.userAgent);

  // -- Get config values --
  sogsUrl = config.sogs_json_url;
  if (!sogsUrl) {
    alert('Missing SOGS (meta.json) URL in config.sogs_json_url.');
    return;
  }

  minZoom = parseFloat(config.minZoom || "1");
  maxZoom = parseFloat(config.maxZoom || "20");
  minAngle = parseFloat(config.minAngle || "-45");
  maxAngle = parseFloat(config.maxAngle || "90");
  minAzimuth = (config.minAzimuth !== undefined) ? parseFloat(config.minAzimuth) : -360;
  maxAzimuth = (config.maxAzimuth !== undefined) ? parseFloat(config.maxAzimuth) : 360;
  minPivotY = parseFloat(config.minPivotY || "0");
  minY = (config.minY !== undefined) ? parseFloat(config.minY) : 0;

  modelX = (config.modelX !== undefined) ? parseFloat(config.modelX) : 0;
  modelY = (config.modelY !== undefined) ? parseFloat(config.modelY) : 0;
  modelZ = (config.modelZ !== undefined) ? parseFloat(config.modelZ) : 0;
  modelScale = (config.modelScale !== undefined) ? parseFloat(config.modelScale) : 1;
  modelRotationX = (config.modelRotationX !== undefined) ? parseFloat(config.modelRotationX) : 0;
  modelRotationY = (config.modelRotationY !== undefined) ? parseFloat(config.modelRotationY) : 0;
  modelRotationZ = (config.modelRotationZ !== undefined) ? parseFloat(config.modelRotationZ) : 0;

  const cameraX = (config.cameraX !== undefined) ? parseFloat(config.cameraX) : 0;
  const cameraY = (config.cameraY !== undefined) ? parseFloat(config.cameraY) : 2;
  const cameraZ = (config.cameraZ !== undefined) ? parseFloat(config.cameraZ) : 5;
  const cameraXPhone = (config.cameraXPhone !== undefined) ? parseFloat(config.cameraXPhone) : cameraX;
  const cameraYPhone = (config.cameraYPhone !== undefined) ? parseFloat(config.cameraYPhone) : cameraY;
  const cameraZPhone = (config.cameraZPhone !== undefined) ? parseFloat(config.cameraZPhone) : (cameraZ * 1.5);

  chosenCameraX = isMobile ? cameraXPhone : cameraX;
  chosenCameraY = isMobile ? cameraYPhone : cameraY;
  chosenCameraZ = isMobile ? cameraZPhone : cameraZ;

  // -- DOM Elements --
  const canvasId = 'canvas-' + instanceId;
  const progressDialog = document.getElementById('progress-dialog-' + instanceId);
  const viewerContainer = document.getElementById('viewer-container-' + instanceId);

  // Remove old canvas if any
  let oldCanvas = document.getElementById(canvasId);
  if (oldCanvas) oldCanvas.remove();

  // Create and add canvas
  const canvas = document.createElement('canvas');
  canvas.id = canvasId;
  canvas.className = 'ply-canvas';
  canvas.style.width = "100%";
  canvas.style.height = "100%";
  canvas.setAttribute('tabindex', '0');
  viewerContainer.insertBefore(canvas, progressDialog);
  canvas.style.touchAction = "none";
  canvas.style.webkitTouchCallout = "none";
  canvas.addEventListener('gesturestart', e => e.preventDefault());
  canvas.addEventListener('gesturechange', e => e.preventDefault());
  canvas.addEventListener('gestureend', e => e.preventDefault());
  canvas.addEventListener('dblclick', e => e.preventDefault());
  canvas.addEventListener('touchstart', e => { if (e.touches.length > 1) e.preventDefault(); }, { passive: false });
  canvas.addEventListener('wheel', (e) => { e.preventDefault(); }, { passive: false });

  progressDialog.style.display = 'block';

  // --- PlayCanvas Graphics Device ---
  let device;
  try {
    device = await pc.createGraphicsDevice(canvas, {
      deviceTypes: ["webgl2"],
      antialias: false,
      glslangUrl: "https://playcanvas.vercel.app/static/lib/glslang/glslang.js",
      twgslUrl: "https://playcanvas.vercel.app/static/lib/twgsl/twgsl.js"
    });
    device.maxPixelRatio = Math.min(window.devicePixelRatio, 2);
  } catch (e) {
    alert('Failed to create PlayCanvas GraphicsDevice: ' + e);
    return;
  }

  // --- PlayCanvas AppBase (modern) ---
  let appOpts = new pc.AppOptions();
  appOpts.graphicsDevice = device;
  appOpts.mouse = new pc.Mouse(canvas);
  appOpts.touch = new pc.TouchDevice(canvas);
  appOpts.componentSystems = [
    pc.RenderComponentSystem,
    pc.CameraComponentSystem,
    pc.LightComponentSystem,
    pc.ScriptComponentSystem,
    pc.GSplatComponentSystem
  ];
  appOpts.resourceHandlers = [
    pc.TextureHandler,
    pc.ContainerHandler,
    pc.ScriptHandler,
    pc.GSplatHandler
  ];

  app = new pc.AppBase(canvas);
  app.init(appOpts);

  // Fill/resize
  app.setCanvasFillMode(pc.FILLMODE_NONE);
  app.setCanvasResolution(pc.RESOLUTION_AUTO);

  resizeObserver = new ResizeObserver(entries => {
    entries.forEach(entry => {
      app.resizeCanvas(entry.contentRect.width, entry.contentRect.height);
    });
  });
  resizeObserver.observe(viewerContainer);

  window.addEventListener('resize', () => app.resizeCanvas(viewerContainer.clientWidth, viewerContainer.clientHeight));
  app.on('destroy', () => resizeObserver.disconnect());

  // --- Assets: GSplat model + orbit camera script ---
  const assets = {
    model: new pc.Asset('gsplat', 'gsplat', { url: sogsUrl }),
    orbit: new pc.Asset('orbit', 'script', { url: "https://mikafil-viewer-sgos.static.hf.space/orbit-camera.js" })
    // Optionally add others if needed
  };
  for (const key in assets) app.assets.add(assets[key]);

  const loader = new pc.AssetListLoader(Object.values(assets), app.assets);
  loader.load(() => {
    app.start();
    progressDialog.style.display = 'none';

    // --- Add GSplat Model ---
    modelEntity = new pc.Entity('model');
    modelEntity.addComponent('gsplat', { asset: assets.model });
    modelEntity.setLocalPosition(modelX, modelY, modelZ);
    modelEntity.setLocalEulerAngles(modelRotationX, modelRotationY, modelRotationZ);
    modelEntity.setLocalScale(modelScale, modelScale, modelScale);
    app.root.addChild(modelEntity);

    // --- Camera ---
    cameraEntity = new pc.Entity('camera');
    cameraEntity.addComponent('camera', {
      clearColor: new pc.Color(1, 1, 1, 1)
    });
    cameraEntity.setPosition(chosenCameraX, chosenCameraY, chosenCameraZ);
    cameraEntity.lookAt(modelEntity.getPosition());
    cameraEntity.addComponent('script');
    cameraEntity.script.create('orbitCamera', {
      attributes: {
        focusEntity: modelEntity,
        inertiaFactor: 0.2,
        distanceMax: maxZoom,
        distanceMin: minZoom,
        pitchAngleMax: maxAngle,
        pitchAngleMin: minAngle,
        yawAngleMax: maxAzimuth,
        yawAngleMin: minAzimuth,
        minY: minY,
        frameOnStart: false
      }
    });
    cameraEntity.script.create('orbitCameraInputMouse');
    cameraEntity.script.create('orbitCameraInputTouch');
    app.root.addChild(cameraEntity);

    app.resizeCanvas(viewerContainer.clientWidth, viewerContainer.clientHeight);
    app.once('update', () => resetViewerCamera());

    // --- Tooltips (optional) ---
    try {
      if (config.tooltips_url) {
        import('./tooltips.js').then(tooltipsModule => {
          tooltipsModule.initializeTooltips({
            app,
            cameraEntity,
            modelEntity,
            tooltipsUrl: config.tooltips_url,
            defaultVisible: !!config.showTooltipsDefault,
            moveDuration: config.tooltipMoveDuration || 0.6
          });
        }).catch(e => {});
      }
    } catch (e) {}

    viewerInitialized = true;
  });
}

// --- Reset camera helper ---
export function resetViewerCamera() {
  try {
    if (!cameraEntity || !modelEntity || !app) return;
    const orbitCam = cameraEntity.script.orbitCamera;
    if (!orbitCam) return;

    const modelPos = modelEntity.getPosition();
    const tempEnt = new pc.Entity();
    tempEnt.setPosition(chosenCameraX, chosenCameraY, chosenCameraZ);
    tempEnt.lookAt(modelPos);

    const dist = new pc.Vec3().sub2(
      new pc.Vec3(chosenCameraX, chosenCameraY, chosenCameraZ),
      modelPos
    ).length();

    cameraEntity.setPosition(chosenCameraX, chosenCameraY, chosenCameraZ);
    cameraEntity.lookAt(modelPos);

    orbitCam.pivotPoint = modelPos.clone();
    orbitCam._targetDistance = dist;
    orbitCam._distance = dist;

    const rot = tempEnt.getRotation();
    const fwd = new pc.Vec3();
    rot.transformVector(pc.Vec3.FORWARD, fwd);

    const yaw = Math.atan2(-fwd.x, -fwd.z) * pc.math.RAD_TO_DEG;
    const yawQuat = new pc.Quat().setFromEulerAngles(0, -yaw, 0);
    const rotNoYaw = new pc.Quat().mul2(yawQuat, rot);
    const fNoYaw = new pc.Vec3();
    rotNoYaw.transformVector(pc.Vec3.FORWARD, fNoYaw);
    const pitch = Math.atan2(fNoYaw.y, -fNoYaw.z) * pc.math.RAD_TO_DEG;

    orbitCam._targetYaw = yaw;
    orbitCam._yaw = yaw;
    orbitCam._targetPitch = pitch;
    orbitCam._pitch = pitch;
    if (orbitCam._updatePosition) orbitCam._updatePosition();

    tempEnt.destroy();
  } catch (e) {
    // Silent fail
  }
}