/**
 * rigging.js — prep-phase rig selection and hardware economy.  [Lane B]
 *
 * The money half of the sail. Ports the prototype's economy verbatim ($80
 * budget, $5/$15/$30 hardware, $15 spare) and adds the state machine around it:
 * which anchors are rigged, what hangs at each corner, how tight, how many
 * spares in the bag.
 *
 * Kept three-free and DOM-free like sail.js so it is testable headless. The
 * picking/DOM layer is deliberately NOT here yet — it needs Lane A's camera and
 * anchor markers, which do not exist at time of writing; see createRiggingUI at
 * the bottom for the seam it will plug into.
 */

import { HARDWARE, START_BUDGET, SPARE_COST, FIXED_DT } from './contracts.js';
import { SailRig, orderRing, TENSION_MIN, TENSION_MAX } from './sail.js';

export { START_BUDGET, SPARE_COST };
export const MAX_CORNERS = 4;
export const DEFAULT_TENSION = 1.0;

/**
 * Fabric — DESIGN.md's "fabric choice is a forecast bet", and it is a BET, not a
 * purchase. Both cost $0.
 *
 * That pricing is a finding, not laziness. SPRINT6 asked me to "price the
 * difference"; I measured it instead and there is no price at which membrane is
 * a sane buy, because it is strictly dominated as an upgrade:
 *
 *   what membrane buys   +26% hail blocked — but ONLY on the pea-hail nights
 *                        (hailBlockFor(0.7, 0.3) = 0.74), which are the EASY
 *                        ones; on storm_02 (1.3) and the ice night (1.4) a
 *                        knitted cloth already blocks 100%, because a 2 cm
 *                        stone cannot pass a 2 mm weave — C's ruling.
 *                        Plus rain, which is 0.25 of the drain against hail's
 *                        5.0, i.e. ~5% of the damage.
 *   what membrane costs  DOUBLE the wind load (porosity halves the pressure
 *                        term), and it PONDS — the flat-sail killer, needing
 *                        the broom.
 *
 * Charge for that and you have shipped a trap. Free, it is the real forecast
 * bet the design describes: take the cloth when the night is windy (which is
 * every night with big hail), take the membrane when the hail is small and the
 * wind is mild and you want the rain off too. If Lane A ever raises rain's drain
 * weight, membrane earns a price and this comment is the place to start.
 */
export const FABRIC = [
  { id: 'cloth', name: 'shade cloth', porosity: 0.30, cost: 0, blurb: 'wind blows through — half the load, sheds water, leaks the finest hail' },
  { id: 'membrane', name: 'waterproof membrane', porosity: 0, cost: 0, blurb: 'stops rain and every stone — full wind load, and it ponds' },
];
export const DEFAULT_FABRIC = FABRIC[0];

const clamp = (v, lo, hi) => (v < lo ? lo : v > hi ? hi : v);

const OK = { ok: true };
const fail = (reason) => ({ ok: false, reason });

export class RiggingSession {
  /**
   * @param {object} opts
   * @param {Array}  opts.anchors  world.anchors — [{id, pos, type, sway?}]
   * @param {number} opts.budget   starting cash
   */
  constructor({ anchors = [], budget = START_BUDGET } = {}) {
    this.anchors = anchors;
    this._startBudget = budget;
    this.reset();
  }

  /**
   * Back to an empty prep phase, same anchors and starting budget. Lane A's
   * "play again" reaches into the state machine to fake a fresh round rather
   * than rebuilding the session, so this owns the field list — add a field
   * above, reset it here.
   */
  reset() {
    this.budget = this._startBudget;
    this.tension = DEFAULT_TENSION;
    this.spares = 0;
    this.fabric = DEFAULT_FABRIC;
    /** @type {{anchorId: string, hw: object}[]} — ring-ordered once 4 are rigged */
    this.picks = [];
    return this;
  }

  /**
   * Re-bank the shop for a new night.  [Lane A's ask — THREADS, SPRINT10]
   *
   * A had to poke `_startBudget` and then call `reset()` from main.js — their
   * self-described "one private touch" into this module, done loudly in a
   * comment rather than by forking the file. This is that pair, named.
   *
   * It RESETS, deliberately. A new bank only ever arrives at a night boundary
   * (main.js sets it at the forecast), and carrying last night's picks into a
   * re-banked shop would leave four corners rigged that this wallet never paid
   * for — `budget` would say $80 with $20 of hardware already hanging in the
   * yard. "New budget" and "fresh prep phase" are the same event here; splitting
   * them would only move the bug into the caller.
   */
  setBudget(n) {
    this._startBudget = n;
    return this.reset();
  }

  /**
   * Re-point the session at a new yard's anchors.  [SPRINT11 — the site switch]
   *
   * Picks die with the old site: they are anchor IDs, and `p4` on the backyard
   * is not `p4` on the corner block. Keeping them would rig a quad out of
   * anchors that no longer exist.
   */
  setAnchors(anchors) {
    this.anchors = anchors;
    return this.reset();
  }

  get spent() { return START_BUDGET - this.budget; }
  get canStart() { return this.picks.length === MAX_CORNERS; }
  isRigged(anchorId) { return this.picks.some((p) => p.anchorId === anchorId); }
  pickOf(anchorId) { return this.picks.find((p) => p.anchorId === anchorId) || null; }

  /** Charge (or refund, when amount is negative) against the budget. */
  _spend(amount) {
    if (this.budget - amount < 0) return false;
    this.budget -= amount;
    return true;
  }

  /** Rig a corner at an anchor, starting on the cheapest hardware (prototype). */
  rig(anchorId) {
    const a = this.anchors.find((x) => x.id === anchorId);
    if (!a) return fail('no such anchor');
    if (this.isRigged(anchorId)) return fail('already rigged');
    if (this.picks.length >= MAX_CORNERS) return fail('a sail has four corners');
    if (!this._spend(HARDWARE[0].cost)) return fail('not enough budget');
    this.picks.push({ anchorId, hw: HARDWARE[0] });
    this._reorder();
    return OK;
  }

  /**
   * Unrig a corner and refund its hardware. Not in the prototype (which had no
   * way back from a misclick) but it is a pure refund, so it costs the economy
   * nothing and saves the player a restart.
   */
  unrig(anchorId) {
    const i = this.picks.findIndex((p) => p.anchorId === anchorId);
    if (i < 0) return fail('not rigged');
    this.budget += this.picks[i].hw.cost;
    this.picks.splice(i, 1);
    return OK;
  }

  /** Cycle a corner's hardware to the next tier, paying (or refunding) the difference. */
  cycleHardware(anchorId) {
    const p = this.pickOf(anchorId);
    if (!p) return fail('not rigged');
    const next = HARDWARE[(HARDWARE.indexOf(p.hw) + 1) % HARDWARE.length];
    if (!this._spend(next.cost - p.hw.cost)) return fail('not enough budget');
    p.hw = next;
    return OK;
  }

  /**
   * Put specific hardware on a rigged corner, paying the difference.
   *
   * THROWS on hardware that isn't in the shop, where every other failure here
   * returns {ok:false}. The split is deliberate and it is about who made the
   * mistake: 'not rigged' and 'not enough budget' are things a PLAYER does, and
   * the UI tickers the reason. Hardware that isn't in HARDWARE is not reachable
   * by any click — the picking UI only ever cycles the shop's own list — so it
   * can only mean a caller passed the wrong thing, and returning {ok:false} for
   * that just lets a bug walk.
   *
   * It already had: balance.test's own comment records "setHardware fails
   * silently, cheap hardware stays on, p2/p4 tear off" — a loadout that quietly
   * kept its carabiners and then reported a cascade as if it were a finding.
   * The SPRINT12 QA pass hit the same edge from the other side. A wrong tier is
   * invisible in the result (the sim just runs, cheaper), so this is exactly the
   * class of mistake that must not be ignorable.
   */
  setHardware(anchorId, hw) {
    if (!HARDWARE.includes(hw)) {
      throw new TypeError(
        `setHardware("${anchorId}", ${JSON.stringify(hw?.name ?? hw)}) — not a shop item. ` +
        `Pass a HARDWARE entry (${HARDWARE.map((h) => h.name).join(' / ')}), not a name or a copy: ` +
        'the shop compares by identity. A returned {ok:false} here would leave the old ' +
        'hardware on the corner and the sim would run cheaper without telling anyone.');
    }
    const p = this.pickOf(anchorId);
    if (!p) return fail('not rigged');
    if (!this._spend(hw.cost - p.hw.cost)) return fail('not enough budget');
    p.hw = hw;
    return OK;
  }

  /**
   * Pick the cloth. Free either way (see FABRIC) — it's a forecast bet, so the
   * cost is which night you're wrong on, not dollars.
   * @param {object|string} f  a FABRIC entry or its id
   */
  setFabric(f) {
    const pick = typeof f === 'string' ? FABRIC.find((x) => x.id === f) : f;
    if (!pick || !FABRIC.includes(pick)) return fail('unknown fabric');
    if (!this._spend(pick.cost - this.fabric.cost)) return fail('not enough budget');
    this.fabric = pick;
    return OK;
  }

  /** 0.6 loose (soaks gusts, flogs) .. 1.4 drum tight (no flap, shock-loads). */
  setTension(v) {
    this.tension = clamp(v, TENSION_MIN, TENSION_MAX);
    return this.tension;
  }

  /** Buy (or sell back) spares in prep. `spares` is the count on the shed table. */
  setSpares(n) {
    n = Math.max(0, Math.floor(n));
    const delta = (n - this.spares) * SPARE_COST;
    if (!this._spend(delta)) return fail('not enough budget');
    this.spares = n;
    return OK;
  }

  /**
   * How many spares are still on the shed table.  [D's ask, SPRINT13]
   *
   * The read half of the seam D found: interact.js gated the table pickup on
   * `!player.carrying` alone and never looked at the count, so a player who
   * bought ZERO walked off with unlimited free shackles mid-storm — the whole
   * "limited hands, two trips" economy the ladder's cost is balanced against was
   * free on the spare side, live on the public deploy.
   */
  get sparesRemaining() { return this.spares; }

  /**
   * Take one spare off the table.  [D's ask, SPRINT13]
   *
   * The consume half. `spares` IS the count on the table, not a purchased total
   * held elsewhere, so taking one decrements it — and that quietly fixes a
   * SECOND bug for free: main.js:720 already refunds `session.spares * SPARE_COST`
   * as "a spare you never had to use", so before this you were refunded for
   * spares you'd already spent. Decrementing here makes that line honest with no
   * change to main.js. reset() zeroes the count between nights, so nothing
   * carries.
   *
   * interact.js calls `canUse: () => !p.carrying && session.sparesRemaining > 0`
   * and `onDone: () => session.takeSpare()` once A threads the session into
   * wireYardActions — D has the interact side ready.
   */
  takeSpare() {
    if (this.spares <= 0) return fail('no spares left on the table');
    this.spares -= 1;
    return OK;
  }

  /**
   * Ring-order the picks by angle around their ground-plane centroid, so corner
   * i of the cloth grid always maps to a neighbouring anchor. Without it,
   * picking anchors in a silly order knots the sail through itself.
   */
  _reorder() {
    if (this.picks.length < MAX_CORNERS) return;
    const byId = new Map(this.picks.map((p) => [p.anchorId, p]));
    const ring = orderRing(this.picks.map((p) => this.anchors.find((a) => a.id === p.anchorId)));
    this.picks = ring.map((a) => byId.get(a.id));
  }

  /** Hand the finished rig to the sim. Mirrors contracts.js sailRig.attach(). */
  commit(rig) {
    if (!this.canStart) throw new Error(`sail needs ${MAX_CORNERS} corners, have ${this.picks.length}`);
    // Fabric before attach: porosity scales the wind pressure term and decides
    // whether the cloth ponds, so the sail has to know what it's made of before
    // it is built. (It's also half of the wild night's only winnable line —
    // shade cloth + C's 0.40 downdraft drop p1 to 1.08 kN, under a $5
    // carabiner's rating, which is the $10 that closes the $90 -> $80 gap.)
    if (rig.setFabric) rig.setFabric(this.fabric);
    return rig.attach(this.picks.map((p) => p.anchorId), this.picks.map((p) => p.hw), this.tension);
  }

  /**
   * What a pick's corner actually fails at, in newtons: hardware rating × the
   * anchor's ratingHint (`?? 1` mirrors sail.js — world.js guarantees the field,
   * but a session can be handed bare test anchors that never met world.js).
   */
  _effRating(p) {
    const a = this.anchors.find((x) => x.id === p.anchorId);
    return p.hw.rating * (a?.ratingHint ?? 1);
  }

  /**
   * What each corner carries in STILL AIR at the current tension, newtons.
   * Null until four corners are picked — a quad is the only thing that has a load.
   *
   * D's ask, SPRINT13 ("the first lesson always costs ~$60"): the tension dial
   * has a static price and the panel never showed it. At 1.4 the standing load
   * alone is ~1.4-1.5 kN/corner on a 46 m² quad, which is over every tier the
   * shop sells except a rated shackle on an honest anchor — so a drum-tight sail
   * rips corners off during PREP, on the calm day, before a breath of wind. That
   * reads fair when you can see it coming and daylight robbery when you can't.
   *
   * Still air, not "calm day": this is the number the DIAL owns. Gravity and
   * tension only — no gusts, no forecast, nothing that could be mistaken for a
   * prediction about tonight. The storm multiplies this by ~3-8x and the panel
   * says "standing" for exactly that reason.
   *
   * Cheap enough to call on a click: 15.6 ms of settle on a 10×10 grid (measured),
   * and the result is cached by the caller on (picks, tension, fabric) — hardware
   * doesn't move the cloth, so cycling tiers, the most-clicked action in prep,
   * never recomputes.
   *
   * 4 s of settle, not 2: the cloth arrives at rest through a damped oscillation,
   * and at low tension 2 s still reads ~4% high on the way down (0.195 vs 0.188
   * kN converged). 4 s is inside 1% everywhere measured and costs 8 ms more, once.
   *
   * Cross-checked against the game the honest way: on the corner block's real
   * 46 m² carport quad this reports a worst corner of 1.41 kN at tension 1.4 —
   * D measured "~1.4-1.5 kN/corner at 46 m²" in play, from the other side.
   */
  standingLoads({ settle = 4.0 } = {}) {
    if (this.picks.length !== MAX_CORNERS) return null;
    const rig = new SailRig({ anchors: this.anchors, gridN: 10, porosity: this.fabric.porosity });
    /**
     * UNBREAKABLE hardware, deliberately — and this is the whole subtlety.
     *
     * The preview measures the LOAD, which is a fact about geometry and the
     * dial; it is not a rehearsal of tonight. Attach it with the player's real
     * tiers and at tension 1.4 the corners genuinely rip during this very
     * settle (D measured it: three go at t≈0.5 on the calm day) — and a broken
     * corner carries nothing, so the panel would print a serene `0.00 kN` for
     * the exact corner about to take the night down. The first version of this
     * did that and the selftest below caught it.
     *
     * So: measure the load unbroken, then let the PANEL compare it against the
     * corner's real effective rating and say "RIPS AT REST". The number stays
     * honest and the warning lands where the player can act on it.
     */
    const UNBREAKABLE = { name: 'preview', cost: 0, rating: Infinity };
    rig.attach(this.picks.map((p) => p.anchorId), Array(MAX_CORNERS).fill(UNBREAKABLE), this.tension);
    // Still air. `sample` must honour the out-param — sail.js reuses one vector.
    const stillAir = {
      sample: (_p, _t, out) => (out ? out.set(0, 0, 0) : { x: 0, y: 0, z: 0 }),
      rainMmPerHour: () => 0,
    };
    for (let i = 0, n = Math.round(settle / FIXED_DT); i < n; i++) rig.step(FIXED_DT, stillAir, i * FIXED_DT);
    const out = {};
    for (const c of rig.corners) out[c.anchorId] = c.load;
    return out;
  }

  /** Everything the HUD needs to draw the prep panel, in one read. */
  get summary() {
    return {
      budget: this.budget,
      spent: this.spent,
      tension: this.tension,
      spares: this.spares,
      fabric: { id: this.fabric.id, name: this.fabric.name, porosity: this.fabric.porosity, cost: this.fabric.cost, blurb: this.fabric.blurb },
      canStart: this.canStart,
      // `effRating` rides along with the bare one: D's panel-honesty gap — the
      // weak-link arrow reasoned on rating × ratingHint while the printed kN was
      // the bare steel, so a cold player saw four identical 1.2s and one
      // unexplained arrow. The panel prints the effective number now; the bare
      // rating stays for anyone who wants to show the steel's own spec.
      corners: this.picks.map((p) => ({
        anchorId: p.anchorId, hw: p.hw.name, rating: p.hw.rating, cost: p.hw.cost,
        effRating: this._effRating(p),
        hint: this.anchors.find((x) => x.id === p.anchorId)?.ratingHint ?? 1,
      })),
      // The weak link is the lowest EFFECTIVE rating — hw.rating × the anchor's
      // ratingHint, the same product sail.js fails a corner on (SPRINT12, A's
      // ruling). D's #7: this used to reduce on hw.rating alone with strict <,
      // so four identical carabiners flagged whichever was clicked FIRST — the
      // label pointed at click order, not steel, and on the corner block it
      // named the genuinely worst anchor only by luck. Ratings ties still keep
      // the first pick, honestly: if the products are equal the steel really is
      // interchangeable and there is no "genuinely worst" to point at.
      weakest: this.picks.length
        ? this.picks.reduce((w, p) => (this._effRating(p) < this._effRating(w) ? p : w)).anchorId
        : null,
    };
  }
}

/**
 * Prep-phase picking UI.
 *
 * Everything above is the rules; this is only the hands. It renders its own
 * anchor markers because the yard has none to raycast against — world.js builds
 * posts and trunks, not pick targets — and marker styling is prep-phase UI, so
 * it belongs to this lane rather than to the terrain.
 *
 * Controls: LMB an anchor to rig it, LMB again to cycle its hardware,
 * shift-LMB to pull it off for a full refund, [ and ] for tension, S for the
 * spare. RMB is left alone — that's the camera's orbit. Enter belongs to Lane
 * A's phase machine, which calls commit() on the way out of prep.
 *
 * @param {object}   o
 * @param {object}   o.scene        THREE.Scene to hang markers in
 * @param {object}   o.camera       cameraRig.object — what we raycast from
 * @param {Element}  o.domElement   renderer.domElement — where clicks land
 * @param {object}   o.world        needs world.anchors
 * @param {function} o.onCommit     (anchorIds, hwChoices, tension) => void — Lane A's rigSail
 * @param {function} [o.onMessage]  (text) => void — refusals, for the event ticker
 * @param {boolean}  [o.panel=true] draw the built-in prep panel; false if hud.js takes it over
 */
export async function createRiggingUI({
  scene, camera, domElement, world,
  onCommit, onMessage = () => {}, panel = true,
} = {}) {
  const THREE = await import('../vendor/three.module.js');
  const session = new RiggingSession({ anchors: world.anchors });

  // --- markers -----------------------------------------------------------
  const group = new THREE.Group();
  group.visible = false;
  scene.add(group);

  const DIM = 0x33424c;
  const ringGeo = new THREE.TorusGeometry(0.28, 0.05, 8, 20);
  const dotGeo = new THREE.SphereGeometry(0.1, 10, 8);
  // What you click is NOT what you see: the ring's tube is 5 cm, which at yard
  // distance is a couple of pixels and unhittable. Pick against an invisible
  // sphere big enough to mean "that anchor" and let the ring just be the read.
  const pickGeo = new THREE.SphereGeometry(0.45, 8, 6);
  const pickMat = new THREE.MeshBasicMaterial({ visible: false });

  const makeMarker = (a) => {
    const mat = new THREE.MeshBasicMaterial({ color: DIM, transparent: true, opacity: 0.9 });
    const ring = new THREE.Mesh(ringGeo, mat);
    const dot = new THREE.Mesh(dotGeo, mat);
    const hit = new THREE.Mesh(pickGeo, pickMat);
    hit.userData.anchorId = a.id;
    const holder = new THREE.Group();
    holder.add(ring, dot, hit, makeLabel(THREE, a.id.toUpperCase()));
    group.add(holder);
    return { anchor: a, holder, ring, dot, hit, mat, label: holder.children[3] };
  };

  /** One marker's GPU-side leftovers. The shared geometries are NOT ours to free. */
  const disposeMarker = (m) => {
    group.remove(m.holder);
    m.mat.dispose();
    m.label.material.map?.dispose();   // each label is its own canvas texture
    m.label.material.dispose();
  };

  // `let`, not `const`: setWorld rebuilds both on a site change.
  let markers = world.anchors.map(makeMarker);
  let pickTargets = markers.map((m) => m.hit);

  // --- quad preview ------------------------------------------------------
  // A closed loop through the ring-ordered picks: this is the shape you are
  // about to build, drawn before you commit to it.
  const previewGeo = new THREE.BufferGeometry();
  previewGeo.setAttribute('position', new THREE.BufferAttribute(new Float32Array(5 * 3), 3));
  const preview = new THREE.Line(
    previewGeo,
    new THREE.LineDashedMaterial({ color: 0xffd27a, dashSize: 0.35, gapSize: 0.25 }),
  );
  preview.frustumCulled = false;
  group.add(preview);

  // --- panel -------------------------------------------------------------
  const el = panel ? document.createElement('div') : null;
  if (el) {
    el.id = 'rigging-panel';
    el.style.cssText = `position:fixed;top:12px;left:12px;z-index:20;display:none;
      background:#0d1418e0;border:1px solid #2c3a44;border-radius:6px;padding:10px 12px;
      font:12px/1.65 ui-monospace,Menlo,monospace;color:#dde5ea;min-width:280px;
      white-space:pre;pointer-events:none`;
    document.body.appendChild(el);
  }

  let active = false;
  let hovered = null;

  const ndc = new THREE.Vector2();
  const ray = new THREE.Raycaster();
  const scratch = new THREE.Vector3();

  function pickAt(ev) {
    const r = domElement.getBoundingClientRect();
    ndc.x = ((ev.clientX - r.left) / r.width) * 2 - 1;
    ndc.y = -((ev.clientY - r.top) / r.height) * 2 + 1;
    ray.setFromCamera(ndc, camera);
    return ray.intersectObjects(pickTargets, false)[0]?.object.userData.anchorId ?? null;
  }

  function say(result) {
    if (result && result.ok === false) onMessage(result.reason);
    return result;
  }

  function onPointerDown(ev) {
    if (!active || ev.button !== 0) return; // RMB is the camera's
    const id = pickAt(ev);
    if (!id) return;
    ev.preventDefault();
    if (!session.isRigged(id)) say(session.rig(id));
    else if (ev.shiftKey) say(session.unrig(id));
    else say(session.cycleHardware(id));
    refresh();
  }

  function onPointerMove(ev) {
    if (!active) return;
    hovered = pickAt(ev);
    domElement.style.cursor = hovered ? 'pointer' : '';
  }

  function onKeyDown(ev) {
    if (!active) return;
    if (ev.key === '[') session.setTension(session.tension - 0.05);
    else if (ev.key === ']') session.setTension(session.tension + 0.05);
    else if (ev.key.toLowerCase() === 's') say(session.setSpares(session.spares ? 0 : 1));
    else if (ev.key.toLowerCase() === 'f') {
      // The forecast bet, finally reachable. FABRIC and setFabric() shipped in
      // SPRINT6 and the sim honoured porosity all along — but no key, click or
      // HUD line ever reached them, so every rig ever played was DEFAULT_FABRIC.
      // Two entries, so F is a toggle; announce the blurb because the panel
      // line alone doesn't say what the bet IS.
      const next = FABRIC[(FABRIC.indexOf(session.fabric) + 1) % FABRIC.length];
      if (say(session.setFabric(next.id)).ok) onMessage(`${next.name} — ${next.blurb}`);
    }
    else return;
    ev.preventDefault();
    refresh();
  }

  domElement.addEventListener('pointerdown', onPointerDown);
  domElement.addEventListener('pointermove', onPointerMove);
  addEventListener('keydown', onKeyDown);

  /** Ground-plane area of the quad as picked, m² — the 70-192 m² problem, visible. */
  function quadArea() {
    if (session.picks.length !== MAX_CORNERS) return 0;
    const p = session.picks.map((k) => world.anchors.find((a) => a.id === k.anchorId).pos);
    const tri = (a, b, c) =>
      new THREE.Vector3().subVectors(b, a).cross(new THREE.Vector3().subVectors(c, a)).length() * 0.5;
    return tri(p[0], p[1], p[2]) + tri(p[0], p[2], p[3]);
  }

  /**
   * Standing load per corner, cached on (picks, tension).  [D's ask, SPRINT13]
   *
   * The cloth doesn't care what steel hangs off it, so cycling hardware — the
   * most-clicked action in prep — never recomputes. Only closing the quad or
   * moving the dial does, which is exactly when the number changes.
   */
  let standingKey = null, standingCache = null;
  function standing() {
    const key = `${session.picks.map((p) => p.anchorId).join(',')}|${session.tension.toFixed(2)}|${session.fabric.id}`;
    if (key !== standingKey) { standingKey = key; standingCache = session.standingLoads(); }
    return standingCache;
  }

  function refresh() {
    if (!el) return;
    const s = session.summary;
    const load = standing();
    // padEnd(4), not 3: the backyard's ids are all 2-3 chars, but the corner
    // block ships `tr1b` and the column broke the moment a second site existed.
    const rows = world.anchors.map((a) => {
      const pick = session.pickOf(a.id);
      if (!pick) return `  ${a.id.padEnd(4)} ${a.type.padEnd(6)} —`;
      const weak = s.weakest === a.id && session.picks.length > 1 ? '  <- weak link' : '';
      // The EFFECTIVE rating, not the steel's spec — D's panel-honesty gap: the
      // arrow reasoned on rating × hint while this column printed the bare kN,
      // so a carport beam and a house post both read "1.2 kN" and only one of
      // them was telling the truth. This is the number sail.js fails on.
      const corner = s.corners.find((c) => c.anchorId === a.id);
      const eff = (corner.effRating / 1000).toFixed(1);
      // "1.2×0.22" — the hint is shown as the discount it is, so the arrow has
      // a reason on the same line instead of being folded into a smaller number
      // the player can't account for.
      const hint = corner.hint !== 1 ? `×${corner.hint}` : '';
      const st = load?.[a.id] != null ? `${(load[a.id] / 1000).toFixed(2)}` : '—';
      const over = load?.[a.id] != null && load[a.id] > corner.effRating;
      return `  ${a.id.padEnd(4)} ${pick.hw.name.padEnd(14)} ${st.padStart(4)}/${eff.padEnd(4)}kN${hint.padEnd(6)} $${pick.hw.cost}` +
        `${over ? '  !! RIPS AT REST' : weak}`;
    });
    const area = quadArea();
    // D, SPRINT13: "the panel never shows standing kN at the chosen tension, so
    // the first lesson always costs ~$60". At 1.4 the standing load alone is
    // over most of the shop. Said as a per-corner average because that's the
    // number the DIAL owns; the per-corner column above is where you find which
    // one is about to let go.
    const vals = load ? Object.values(load) : [];
    const avg = vals.length ? vals.reduce((x, y) => x + y, 0) / vals.length : 0;
    const worst = vals.length ? Math.max(...vals) : 0;
    const standingLine = vals.length
      ? `standing ≈${(avg / 1000).toFixed(2)} kN/corner at this tension (worst ${(worst / 1000).toFixed(2)}) — before any wind`
      : null;
    el.textContent = [
      `PREP — rig four corners        $${s.budget} left`,
      `tension ${s.tension.toFixed(2)}   spare x${s.spares}   ${s.fabric.name}${area ? `   sail ${area.toFixed(0)} m2` : ''}`,
      '',
      ...rows,
      ...(standingLine ? ['', standingLine] : []),
      '',
      s.canStart ? 'ENTER to start the storm' : `pick ${MAX_CORNERS - session.picks.length} more corner(s)`,
      'click anchor: rig / cycle hw   shift-click: remove',
      '[ ] tension    S spare    F fabric    RMB orbit',
    ].join('\n');
  }

  const ui = {
    session,
    get summary() { return { ...session.summary, area: quadArea() }; },
    get canStart() { return session.canStart; },
    get active() { return active; },

    /**
     * Re-point the whole UI at a new yard.  [Lane A's ask — THREADS, SPRINT10]
     *
     * The site switch's last piece. `createRiggingUI` built its markers and its
     * session from `world.anchors` at construction and had no way to re-point
     * them, so on a site change the corner block's markers didn't exist and the
     * panel still listed the backyard. A re-points what they can reach from
     * main.js (`rig.anchors`, `session.anchors`) — which is why night 3 has been
     * riggable from code and from the audit but not from the MOUSE. This is the
     * mouse.
     *
     * A calls it inside `loadSiteInto`, guarded (`rigging.setWorld?.(world)`),
     * so it lights up the day it lands with no change on their side.
     *
     * Markers are rebuilt, not repositioned: the anchor SET changes across sites
     * (12 in the backyard, 10 on the corner block, different ids), so there is no
     * per-marker correspondence to preserve. Each marker owns a material and a
     * canvas-texture label, so the old ones are disposed rather than dropped —
     * five site switches a week, every week, is a real leak otherwise.
     */
    setWorld(w) {
      world = w;
      for (const m of markers) disposeMarker(m);
      markers = world.anchors.map(makeMarker);
      pickTargets = markers.map((m) => m.hit);
      hovered = null;                    // a stale id would highlight nothing, forever
      session.setAnchors(world.anchors); // picks are old-site anchor ids — they die here
      preview.visible = false;
      refresh();
      return ui;
    },

    /** Lane A: call on phaseChange — markers and clicks are prep-only. */
    setActive(on) {
      active = !!on;
      group.visible = active;
      if (el) el.style.display = active ? 'block' : 'none';
      if (!active) domElement.style.cursor = '';
      if (active) refresh();
      return ui;
    },

    /** Markers ride the anchors, so a tree corner wanders before you even rig it. */
    update(dt, t) {
      if (!active) return;
      for (const m of markers) {
        const p = m.anchor.sway ? m.anchor.sway(t) : m.anchor.pos;
        m.holder.position.set(p.x, p.y, p.z);
        m.holder.quaternion.copy(camera.quaternion); // rings face the player
        const pick = session.pickOf(m.anchor.id);
        m.mat.color.setHex(pick ? pick.hw.color : DIM);
        const s = (hovered === m.anchor.id ? 1.35 : 1) * (pick ? 1.15 : 1);
        m.ring.scale.setScalar(s);
        m.label.visible = !!pick || hovered === m.anchor.id;
      }

      const pos = previewGeo.attributes.position;
      if (session.picks.length >= 2) {
        preview.visible = true;
        const n = session.picks.length;
        for (let i = 0; i <= n; i++) {
          const k = session.picks[i % n];
          const a = world.anchors.find((x) => x.id === k.anchorId);
          const p = a.sway ? a.sway(t) : a.pos;
          scratch.set(p.x, p.y, p.z);
          pos.setXYZ(i, scratch.x, scratch.y, scratch.z);
        }
        // degenerate tail so a partial pick doesn't draw a stale segment
        for (let i = session.picks.length + 1; i < 5; i++) pos.setXYZ(i, scratch.x, scratch.y, scratch.z);
        pos.needsUpdate = true;
        previewGeo.setDrawRange(0, session.picks.length + 1);
        preview.computeLineDistances();
      } else {
        preview.visible = false;
      }
    },

    /** Hand the finished rig to Lane A's rigSail. Returns false if it isn't four corners. */
    commit() {
      if (!session.canStart) {
        onMessage(`rig ${MAX_CORNERS - session.picks.length} more corner(s) first`);
        return false;
      }
      onCommit(
        session.picks.map((p) => p.anchorId),
        session.picks.map((p) => p.hw),
        session.tension,
      );
      return true;
    },

    dispose() {
      domElement.removeEventListener('pointerdown', onPointerDown);
      domElement.removeEventListener('pointermove', onPointerMove);
      removeEventListener('keydown', onKeyDown);
      scene.remove(group);
      ringGeo.dispose(); dotGeo.dispose(); pickGeo.dispose(); pickMat.dispose(); previewGeo.dispose();
      preview.material.dispose();
      for (const m of markers) disposeMarker(m);   // same teardown setWorld uses
      el?.remove();
    },
  };

  refresh();
  return ui;
}

/** A cheap canvas-texture nameplate, so anchors read as h1/t2/p1 rather than dots. */
function makeLabel(THREE, text) {
  const c = document.createElement('canvas');
  c.width = 128; c.height = 64;
  const g = c.getContext('2d');
  g.font = 'bold 40px ui-monospace, Menlo, monospace';
  g.textAlign = 'center';
  g.textBaseline = 'middle';
  g.lineWidth = 6;
  g.strokeStyle = '#0d1418';
  g.strokeText(text, 64, 32);
  g.fillStyle = '#dde5ea';
  g.fillText(text, 64, 32);
  const sprite = new THREE.Sprite(new THREE.SpriteMaterial({
    map: new THREE.CanvasTexture(c), depthTest: false, transparent: true,
  }));
  sprite.position.set(0, 0.55, 0);
  sprite.scale.set(0.8, 0.4, 1);
  return sprite;
}
