/**
 * broom.js — DESIGN.md's funniest correct mechanic.  (Lane D, SPRINT5 §Lane D-1)
 *
 * A flat sail pools water. The water is heavier than anything else in the game and it will pull the
 * rig down. The fix is a bloke with a broom walking under the belly and poking it upward — at which
 * point forty kilos of cold water arrives on his head. That is both the correct engineering answer
 * and the joke, and they are the same thing, which is the best kind of mechanic.
 *
 * Everything here defers to the asset. E baked the intent into broom_01_v1.glb:
 *   grip_anchor  extras.carry_type = "broom"
 *   poke_tip     extras.use = "push the pond up from under the sail; soft end, won't hole the cloth"
 *                — on the BRISTLE end, deliberately: a broomstick jabbed at a loaded sail holes it.
 *   root         extras.anim_hint = "reuse Crank/Dig for the poke — no new Mixamo needed"
 * so the carry type, the working end and the animation are all read, not invented.
 *
 * Seam with Lane B (posted in THREADS before either of us built): sailRig.ponds -> [{node,mass,pos}]
 * and drainPondAt(node) -> kg dumped. Duck-typed: with no ponding landed the broom still carries,
 * walks and refuses to poke thin air, and the moment B lands it the whole thing lights up.
 */
// No top-level THREE/GLTFLoader import, deliberately: the vendored addons import the bare specifier
// 'three', which only resolves under index.html's importmap — so importing them here would drag the
// whole GL chain into d.test.js and cost this lane its headless suite (node resolves relative paths
// only). The pond logic below is the part worth asserting and it is pure; the view is loaded
// dynamically, which never happens outside a browser.
export const BROOM_URL = './models/broom_01_v1.glb';

export const BROOM_TUNE = {
  pokeSecs: 1.5,            // matches B's "drain over ~1.5 s"
  reachUp: 3.2,             // m — how high overhead a pond can be and still be pokeable from the grass
  standRadius: 2.0,         // m — how near the pond's ground shadow you must be

  // What lands on you. Calibrate once B's masses are real — these are physical guesses, not measured:
  // a full bucket is ~10 kg, so a splash is nothing, half a bathtub staggers you, and a bathtub
  // puts you down. Flagged in THREADS for the tuning pass.
  splashKg: 15,             // below this it's just cold and funny
  staggerKg: 60,            // above this you lose your footing
  // above staggerKg*2 → flat on your back
};

/**
 * @param {THREE.Object3D} scene
 * @param {object} world     contracts World (dressed)
 * @param {object} interact  Lane D's Interact
 * @param {object} player    PlayerSim
 * @param {object} getRig    () => sailRig — a getter, because rigSail() REPLACES the rig object
 */
export function createBroom(scene, world, interact, player, getRig) {
  const state = { carried: false, view: null, tune: { ...BROOM_TUNE } };

  // Home: against the shed wall. E ships it standing on its head, which is how it lives there.
  const home = { x: 8.2, y: 0, z: 7.0 };
  if (world.shedTable && world.shedTable.pos) {
    home.x = world.shedTable.pos.x - 0.8;
    home.z = world.shedTable.pos.z + 1.0;
  }
  home.y = world.heightAt ? world.heightAt(home.x, home.z) : 0;

  if (scene) {
    import('../vendor/addons/loaders/GLTFLoader.js').then(({ GLTFLoader }) => {
      new GLTFLoader().load(BROOM_URL, (g) => {
        g.scene.traverse((o) => { if (o.isMesh) { o.castShadow = true; o.frustumCulled = false; } });
        state.view = g.scene;
        scene.add(g.scene);
        sync();
      }, undefined, () => { /* no asset: the mechanic still runs, you just can't see the broom */ });
    }).catch(() => { /* headless (selftest/node): logic only, no view */ });
  }

  function sync() {
    if (!state.view) return;
    state.view.visible = !state.carried;
    state.view.position.set(home.x, home.y, home.z);
    state.view.rotation.set(0, 0.9, 0.16);   // slouched against the shed wall
  }

  /** Every pond Lane B is reporting, or [] until they land it. */
  const ponds = () => {
    const rig = getRig && getRig();
    return (rig && Array.isArray(rig.ponds)) ? rig.ponds : [];
  };

  /**
   * The pond this player could actually poke: near enough in plan, low enough overhead.
   * Picks the HEAVIEST reachable one rather than the nearest — if you're standing under two, the
   * one about to break the rig is the one you meant.
   */
  function targetPond() {
    let best = null;
    for (const p of ponds()) {
      if (!p || !p.pos || !(p.mass > 0)) continue;
      const d = Math.hypot(p.pos.x - player.pos.x, p.pos.z - player.pos.z);
      const up = p.pos.y - (player.pos.y + player.climbY);
      if (d > state.tune.standRadius || up > state.tune.reachUp || up < 0) continue;
      if (!best || p.mass > best.mass) best = p;
    }
    return best;
  }

  /** Where to stand: the pond's shadow on the grass. */
  const pokeSpot = () => {
    const p = ponds().reduce((a, b) => (!a || (b && b.mass > a.mass) ? b : a), null);
    if (!p || !p.pos || !(p.mass > 0)) return null;
    return { x: p.pos.x, y: 0, z: p.pos.z };
  };

  const wired = [];

  // 1. take the broom off the shed wall — a third carry type, so it queues behind the same hands
  wired.push(interact.register({
    id: 'broom_take',
    pos: () => (state.carried ? null : home),
    radius: 1.5,
    holdSecs: 0.7,
    clip: 'PickUp',
    label: (p) => (p.carrying ? 'hands full' : 'take the broom'),
    canUse: (p) => !state.carried && !p.carrying && p.climbY < 0.02,
    onDone: (p, t) => { state.carried = true; p.pickUp('broom', t); sync(); },
  }));

  // 2. put it back
  wired.push(interact.register({
    id: 'broom_drop',
    pos: () => (state.carried ? { x: home.x, y: home.y, z: home.z } : null),
    radius: 1.5,
    holdSecs: 0.4,
    clip: 'PickUp',
    label: 'put the broom back',
    canUse: (p) => state.carried && p.carrying === 'broom',
    onDone: (p, t) => { state.carried = false; p.drop(t); sync(); },
  }));

  // 3. THE POKE. Stand under the belly, push up, wear it.
  wired.push(interact.register({
    id: 'broom_poke',
    pos: pokeSpot,
    radius: state.tune.standRadius,
    holdSecs: state.tune.pokeSecs,
    clip: 'Crank',                      // E's anim_hint — no new Mixamo needed
    label: (p) => {
      if (p.carrying !== 'broom') return 'you need the broom';
      const pond = targetPond();
      if (!pond) return 'nothing pooling here';
      return `push the water off (${Math.round(pond.mass)} kg)`;
    },
    // physical gates only — never player.state (see interact.register's note; it cancels its own hold)
    canUse: (p) => {
      const rig = getRig && getRig();
      return p.carrying === 'broom' && !!(rig && rig.drainPondAt) && !!targetPond();
    },
    onDone: (p, t) => {
      const rig = getRig && getRig();
      const pond = targetPond();
      if (!rig || !pond) return;
      // B returns the kg actually dumped; fall back to diffing pondMass() if they'd rather not
      let kg = rig.drainPondAt(pond.node);
      if (typeof kg !== 'number') kg = pond.mass;
      onWater(p, kg, pond, t);
    },
  }));

  /**
   * The payoff. All of it lands on the player, because they are standing directly underneath it —
   * that is not a bug in the plan, it IS the plan.
   */
  function onWater(p, kg, pond, t) {
    p.events.push({ type: 'doused', kg, t });
    const T = state.tune;
    if (kg >= T.staggerKg * 2) {
      // downward and behind: a bathtub arriving on your head does not blow you downwind
      p.knockdown(t, -Math.sin(p.facing), -Math.cos(p.facing));
    } else if (kg >= T.staggerKg) {
      p.staggerHit(t);
    }
    // below splashKg: you just get wet, which is its own reward
  }

  return {
    get carried() { return state.carried; },
    get home() { return home; },
    tune: state.tune,
    ponds,
    targetPond,
    pokeSpot,
    onWater,
    update() { sync(); },
    dispose() { wired.forEach((un) => un()); if (state.view) scene.remove(state.view); },
  };
}