// hands.js — first-person sci-fi hands (FAB "Sci Fi Hands" pack, merged to one GLB
// with clips: Idle, Idle_Fight, Attack_01-04, Energy_Attack_01, Get, Walk_01, Run_01).
// Camera-parented viewmodel: idle/walk bob from the pack's own clips, punch on smash.
import * as THREE from 'three';
import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';

const TUNE = {
  pos: new THREE.Vector3(0, -1.55, 0.25),
  rotY: Math.PI,          // pack forward is +Z; camera looks down -Z
  scale: 1.0,
};

const ATTACKS = ['Attack_01', 'Attack_02', 'Attack_03', 'Attack_04'];

export async function createHands(camera) {
  const gltf = await new GLTFLoader().loadAsync('assets/hands.glb');
  const rig = gltf.scene;
  rig.position.copy(TUNE.pos);
  rig.rotation.y = TUNE.rotY;
  rig.scale.setScalar(TUNE.scale);
  // render on top-ish: keep depth test but bump renderOrder so close geometry
  // rarely swallows the arms; frustum culling off (always in view).
  rig.traverse(o => { if (o.isMesh) { o.frustumCulled = false; o.renderOrder = 5; } });
  camera.add(rig);

  const mixer = new THREE.AnimationMixer(rig);
  const clips = {};
  for (const c of gltf.animations) clips[c.name] = mixer.clipAction(c);
  const has = n => Object.prototype.hasOwnProperty.call(clips, n);

  let current = null;
  let attacking = false;
  function play(name, { once = false, fade = 0.12 } = {}) {
    if (!has(name)) return null;
    const a = clips[name];
    if (current === a && !once) return a;
    if (current) current.fadeOut(fade);
    a.reset().fadeIn(fade);
    if (once) { a.setLoop(THREE.LoopOnce); a.clampWhenFinished = true; }
    a.play();
    current = a;
    return a;
  }

  mixer.addEventListener('finished', () => {
    attacking = false;
    play(lastLocomotion, { fade: 0.15 });
  });

  let lastLocomotion = 'Idle';
  // draw the hands on boot if the pack has a Get clip
  if (has('Get')) { attacking = true; play('Get', { once: true }); }
  else play('Idle');

  return {
    rig,
    tune: TUNE,
    update(dt, moving = false, running = false) {
      const want = running ? 'Run_01' : moving ? 'Walk_01' : 'Idle';
      lastLocomotion = has(want) ? want : 'Idle';
      if (!attacking) play(lastLocomotion, { fade: 0.18 });
      mixer.update(dt);
    },
    attack() {
      attacking = true;
      play(ATTACKS[Math.floor(Math.random() * ATTACKS.length)], { once: true, fade: 0.05 });
    },
    special() {
      attacking = true;
      play('Energy_Attack_01', { once: true, fade: 0.05 });
    },
  };
}