/* 轨道相机与指针交互（旋转/平移/缩放/自适应取景） */
/* ---- camera orbit ---- */
let az = -0.9, po = 1.15, rd = 620, tx = 120, ty = 190, tz = -30;
// lookAt with the world up-axis degenerate-rolls the image when looking near-vertically,
// so top view pins the screen-up to -Z: model X runs right, depth runs down-screen
const UP_Y = new V3(0, 1, 0), UP_TOP = new V3(0, 0, -1);
let camUp = UP_Y.clone();
function fitTo(b) {
  const c = [(b[0][0]+b[1][0])/2, (b[0][1]+b[1][1])/2, (b[0][2]+b[1][2])/2];
  tx = c[0]; ty = c[1]; tz = c[2];
  const s = Math.max(b[1][0]-b[0][0], b[1][1]-b[0][1], b[1][2]-b[0][2]);
  rd = s * 1.78;
  requestRender();
}
let BB = [[1e9,1e9,1e9],[-1e9,-1e9,-1e9]];
/* robust global bounds in the viewer frame (x, z, -y) */
(function(){
  let lo=[1e9,1e9,1e9], hi=[-1e9,-1e9,-1e9];
  for (const m of meshes) { if (m.userData.name.slice(0,4) === 'ENV_') continue;   // 取景只按手臂本体，包络不入包围盒
    const b=m.geometry.boundingBox;
    const a=[b.min.x+m.base.x,b.min.y+m.base.y,b.min.z+m.base.z];
    const c=[b.max.x+m.base.x,b.max.y+m.base.y,b.max.z+m.base.z];
    for(let i=0;i<3;i++){lo[i]=Math.min(lo[i],a[i]);hi[i]=Math.max(hi[i],c[i]);} }
  BB=[lo,hi];
})();
fitTo(BB);
function updCam() {
  cam.up.copy(camUp);
  cam.position.set(tx + rd*Math.sin(po)*Math.cos(az), ty + rd*Math.cos(po), tz + rd*Math.sin(po)*Math.sin(az));
  cam.lookAt(tx, ty, tz);
}
let drag = null, panDist = 0;
cv.addEventListener('pointerdown', e => {
  drag = {x:e.offsetX, y:e.offsetY, b:e.button};
  panDist = 0;
  cv.setPointerCapture(e.pointerId);
});
/* 悬浮拾取限流：射线要对 34 万三角面全量求交（实测 ≈0.5~1.5 ms/次），
   旧版每个 pointermove 都算（rAF 合帧后仍≈显示器刷新率次数）；
   这里加 60 ms 时间配额 + 位置去重，指针静止时一次都不算，尾随仍会补最新位置，
   tooltip 观感不变。点击 / 右键拾取不经过此函数，仍即时求交。 */
let hoverPending = false, lastHoverEv = null, hoverT = -1e9, hoverX = -1, hoverY = -1;
const HOVER_MS = 60;
function schedHover(e) {
  if (e.clientX === hoverX && e.clientY === hoverY) return;   // 没移动：结果不可能变
  hoverX = e.clientX; hoverY = e.clientY; lastHoverEv = e;
  if (hoverPending) return;
  hoverPending = true;
  setTimeout(() => {
    hoverPending = false;
    if (!lastHoverEv || drag) return;
    hoverT = performance.now();
    hover(lastHoverEv);
  }, Math.max(0, HOVER_MS - (performance.now() - hoverT)));
}
cv.addEventListener('pointermove', e => {
  if (!drag) { schedHover(e); return; }
  const dx = e.offsetX - drag.x, dy = e.offsetY - drag.y;
  panDist += Math.abs(dx) + Math.abs(dy);
  drag = {x:e.offsetX, y:e.offsetY, b:drag.b};
  if (drag.b === 0) { az -= dx*0.008; po = Math.min(3.04, Math.max(.05, po - dy*0.008)); }
  else { const r = rd*0.0016; const f = new V3(Math.sin(az),0,Math.cos(az)), ri = new V3().crossVectors(new V3(0,1,0), f).normalize();
    tx -= ri.x*dx*r + f.x*dy*r*0.0; tz -= ri.z*dx*r + f.z*dy*r*0.0; ty += dy*r; }
  requestRender();
});
addEventListener('pointerup', () => drag = null);
cv.addEventListener('wheel', e => { e.preventDefault(); rd *= (1 + Math.sign(e.deltaY)*0.09); requestRender(); }, {passive:false});