HardYards/web/world/js/ladder.js

/**
 * ladder.js — the ladder sub-system.  (Lane D, SPRINT4 decision 12)
 *
 * Why it exists: the house fascia brackets sit at y=2.48 and a 1.72 m person's hands reach 2.20.
 * Two hundred millimetres is the whole mechanic. Everything else in the yard you can rig from the
 * ground — a sail post is tensioned from a cleat at its base, a tree anchor is a strop you throw —
 * but a bracket bolted 2.5 m up a bare wall is not negotiable, and E's ladder tops out at exactly
 * 2.9 m. The asset and the yard were built for each other; this file is the verb between them.
 *
 * The loop it creates is the "limited hands" rule from DESIGN.md doing real work:
 *   ladder and spare are BOTH carry items, and you can only hold one.
 *   So a fascia repair costs two trips — fetch the ladder, plant it, go back for the spare —
 *   while a post repair costs one. The house is the expensive anchor to depend on, which is
 *   exactly what E's ratingHint 0.35 / collateral "gutter" is already telling you in the data.
 *
 * Ownership: Lane D. Self-wires from createPlayer() in player.js, so main.js (Lane A's file) needs
 * no change to get this — it already hands createPlayer the scene, world and interact.
 */
import * as THREE from '../vendor/three.module.js';
import { GLTFLoader } from '../vendor/addons/loaders/GLTFLoader.js';

export const LADDER_URL = './models/ladder_01_v1.glb';

/**
 * Which anchors you cannot rig from the ground.
 *
 * Deliberately keyed on the anchor TYPE, not on a height test. A pure "is it above reach?" rule
 * would rope in the posts (3.95 m) and tree limbs (up to 5.05 m) and turn every single repair into
 * a two-trip ladder job — which is both untrue to how sails are actually rigged and would have
 * silently invalidated the recorded §7 run and Lane B's gate asserts. Decision 12 scopes this to
 * the fascia; this is that scope, in one line, where it can be found and argued with.
 */
export const needsLadder = (anchor) => !!anchor && anchor.type === 'house';

/** Where the player stands to work a fascia anchor: out from the wall, at the anchor's x. */
const STAND_OFF = 0.9;      // m clear of the wall face
const PLACE_RANGE = 2.6;    // m — how close you must be to a fascia anchor to plant the ladder
const RUNG_CLEAR = 0.55;    // m — feet this far below the top rung, so the fascia is at chest height

/**
 * @param {THREE.Object3D} scene
 * @param {object} world     contracts World (must be dressed — anchors are final only after dress())
 * @param {object} interact  Lane D's Interact
 * @param {object} player    the PlayerSim
 * @returns {object} the ladder system
 */
export function createLadder(scene, world, interact, player) {
  const anchors = (world.anchors || []).filter(needsLadder);
  if (!anchors.length) {
    // no fascia in this yard (a bare harness, say) — the whole sub-system is moot, don't half-wire it
    return { placedAt: null, carried: false, needsLadder, isWorking: () => false,
      workY: () => 0, servedAnchor: () => null, update() {}, dispose() {} };
  }

  const state = {
    carried: false,          // in the player's hands
    placedAt: null,          // anchor id, or null while stowed/carried
    base: new THREE.Vector3(),
    topY: 2.9,               // overwritten from the GLB's ladder_top node
    view: null,
  };

  // Home: leaning on the shed, near the spare table but NOT on top of it. Read from world.shedTable
  // so it follows the shed if Lane A moves it. The offset is deliberately ~3 m: at 1.4 m the two
  // prompts overlapped and standing at the ladder offered you "take a spare", which is the kind of
  // thing that reads as a broken game rather than a crowded shed.
  const home = new THREE.Vector3(10.4, 0, 3.4);
  if (world.shedTable && world.shedTable.pos) {
    home.set(world.shedTable.pos.x + 1.4, 0, world.shedTable.pos.z - 2.6);
  }
  home.y = world.heightAt ? world.heightAt(home.x, home.z) : 0;
  state.base.copy(home);

  // --- view -----------------------------------------------------------------
  new GLTFLoader().load(LADDER_URL, (g) => {
    const obj = g.scene;
    const top = obj.getObjectByName('ladder_top');
    if (top) state.topY = top.position.y;
    obj.traverse((o) => { if (o.isMesh) { o.castShadow = true; o.frustumCulled = false; } });
    state.view = obj;
    scene.add(obj);
    syncView();
  }, undefined, () => { /* missing asset: the mechanic still works, you just can't see it */ });

  const LEAN = 0.26;   // rad (~15°) — a ladder stood bolt upright reads as a post, not a ladder
  function syncView() {
    if (!state.view) return;
    state.view.visible = !state.carried;
    state.view.position.copy(state.base);
    const a = state.placedAt && world.anchors.find((x) => x.id === state.placedAt);
    if (a) {
      // planted: yaw so local +Z faces the wall, then tip the head into it. +X rotation carries the
      // top toward local +Z, which is the wall — so the feet stand off and the head rests on it.
      state.view.rotation.set(LEAN, Math.atan2(a.pos.x - state.base.x, a.pos.z - state.base.z), 0);
    } else {
      state.view.rotation.set(0, 0.6, 0.22);   // stowed: slouched against the shed
    }
  }

  /** The fascia anchor this ladder is currently serving, if any. */
  const servedAnchor = () => (state.placedAt ? world.anchors.find((a) => a.id === state.placedAt) : null);

  /** Standing height at the top of the ladder — feet a rung or two down from the very top. */
  const workY = () => Math.max(0, state.topY - RUNG_CLEAR);

  /**
   * True if the player is up THIS ladder and can work the given anchor.
   * Height only, deliberately — hold-E moves the player into `busy`, so testing for state 'atTop'
   * here would make a fascia repair un-usable the moment it started and cancel its own hold.
   */
  function isWorking(anchorId) {
    return state.placedAt === anchorId && player.climbY > workY() - 0.15;
  }

  // --- interactions ---------------------------------------------------------
  const wired = [];

  // 1. pick the ladder up (from its home, or from wherever it's planted)
  wired.push(interact.register({
    id: 'ladder_take',
    pos: () => (state.carried ? null : state.base),
    radius: 1.6,
    holdSecs: 0.8,
    clip: 'PickUp',
    label: (p) => (p.carrying ? 'hands full' : state.placedAt ? 'take the ladder back' : 'take the ladder'),
    canUse: (p) => !state.carried && !p.carrying && p.climbY < 0.02,
    onDone: (p, t) => {
      state.carried = true;
      state.placedAt = null;
      p.pickUp('ladder', t);
      syncView();
    },
  }));

  // 2. plant it at a fascia anchor
  for (const a of anchors) {
    wired.push(interact.register({
      id: `ladder_place_${a.id}`,
      // stand off the wall, on the yard side — the ladder leans in toward the bracket
      pos: () => ({ x: a.pos.x, y: 0, z: a.pos.z + STAND_OFF }),
      radius: PLACE_RANGE,
      holdSecs: 1.0,
      clip: 'PickUp',
      label: `set the ladder under ${a.id}`,
      canUse: (p) => p.carrying === 'ladder',
      onDone: (p, t) => {
        state.carried = false;
        state.placedAt = a.id;
        state.base.set(a.pos.x, world.heightAt ? world.heightAt(a.pos.x, a.pos.z + STAND_OFF) : 0,
          a.pos.z + STAND_OFF);
        p.carrying = null;
        p.events.push({ type: 'ladderPlaced', anchorId: a.id, t });
        syncView();
      },
    }));
  }

  // 3. climb it — only when it's planted, and only from the ground
  wired.push(interact.register({
    id: 'ladder_climb',
    pos: () => (state.placedAt && !state.carried ? state.base : null),
    radius: 1.5,
    holdSecs: 0.4,
    clip: 'PickUp',
    label: 'climb',
    // NB: no test on p.state here. Starting a hold moves the player into `busy`, so a canUse that
    // reads state goes false the instant the hold begins and cancels itself. climbY is the honest
    // gate (are you on the ground?), and locked states can't start a hold anyway.
    canUse: (p) => !!state.placedAt && !state.carried && p.climbY < 0.02,
    onDone: (p, t) => {
      p.pos.x = state.base.x; p.pos.z = state.base.z;       // step onto the rungs
      const a = servedAnchor();
      if (a) p.facing = Math.atan2(a.pos.x - state.base.x, a.pos.z - state.base.z);
      p.climbTo(workY(), t);
    },
  }));

  const api = {
    get placedAt() { return state.placedAt; },
    get carried() { return state.carried; },
    get base() { return state.base; },
    get topY() { return state.topY; },
    workY,
    isWorking,
    servedAnchor,
    needsLadder,

    /**
     * Drive descent from input. Held S climbs down; nothing else can strand you up there, and a
     * knockdown already drops climbY to 0 on its own.
     * player.js calls this each frame from the same input it reads for movement.
     */
    update(dt, t, input) {
      if (player.state === 'atTop' && input && input.z < 0) player.climbTo(0, t);
      syncView();
    },

    dispose() {
      wired.forEach((un) => un());
      if (interact.ladder === api) interact.ladder = null;
      if (state.view) scene.remove(state.view);
    },
  };

  // Publish onto the Interact instance so wireYardActions can find the reach gate without main.js
  // (Lane A's file) having to learn about ladders and thread it through. Interact is Lane D's own
  // class, so this stays inside the lane; an explicit `deps.ladder` still wins if anyone passes one.
  interact.ladder = api;
  return api;
}