// Cutscene layer: page-load entrance and every later respawn.
//
// Physics (resetSim) snaps the duck to the stand keyframe; this module
// owns what the player sees around that snap. Two mutually exclusive
// timelines share the duck's wireframe FX:
//
//   entrance (once)  grid + walls draw in, then the duck scans up
//   respawn  (every kill / Space / loco switch)
//     0.00  duck clipped away, camera glides home from the kill view
//     0.80  camera almost settled -> duck scan-up cues
//     0.90  camera lands
//     1.70  scan done, inputs unlock
//
// rl.js injects the world (rig, grid, camera reset) and the lock/flash
// callbacks; this file never touches MuJoCo.

export const CAM_RESET_S = 0.9;
export const RESPAWN_SCAN_AT = 0.8; // cue scan-up at 80% of the camera glide

const ENTRANCE_GRID_S = 1.1;
const ENTRANCE_WALL_DELAY_S = 0.35;
const ENTRANCE_WALL_S = 0.9;
const ENTRANCE_FX_START_S = 0.6;

const clamp01 = (x) => Math.min(Math.max(x, 0), 1);

export function createCeremony({
  THREE, scene, camera, renderer, fx,
  getRig, grid, wallMats,
  syncRig, startCameraReset,
  setLocked, flashReset,
}) {
  const ENTRANCE_TOTAL_S = Math.max(
    ENTRANCE_GRID_S,
    ENTRANCE_WALL_DELAY_S + ENTRANCE_WALL_S,
    ENTRANCE_FX_START_S + fx.TOTAL_S,
  );

  let fxRig = null;
  let fxPrev = null;
  let entranceT0 = null;
  let entranceFxCued = false;
  let entranceDone = false;
  let respawn = null; // { t0, scanCued } | null
  let entranceFinishedResolve;
  const entranceFinished = new Promise((r) => { entranceFinishedResolve = r; });

  function bind() {
    const rig = getRig();
    if (fxRig === rig) return;
    fx.dispose();
    fx.init({ THREE, scene, rig, camera, renderer });
    rig.placer.traverse((o) => {
      if (o.isMesh && !o.userData.meshName) o.userData.fxOverlay = true;
    });
    fxRig = rig;
  }

  function fxStart() {
    bind();
    fx.start();
    fxPrev = performance.now();
  }
  function fxDrive() {
    if (fxPrev === null || fx.isDone()) return;
    const now = performance.now();
    const dt = Math.min((now - fxPrev) / 1000, 0.25);
    fxPrev = now;
    fx.update(dt);
  }
  function fxForceFinish() {
    if (!fx.isDone()) fx.update(1e3);
  }

  function startEntrance() {
    if (entranceT0 !== null || entranceDone) return;
    entranceT0 = performance.now();
    entranceFxCued = false;
    grid.material.uniforms.uReveal.value = 0;
    for (const m of wallMats) m.uniforms.uReveal.value = 0;
  }

  function driveEntrance() {
    if (entranceT0 === null) return;
    const t = (performance.now() - entranceT0) / 1000;
    grid.material.uniforms.uReveal.value = clamp01(t / ENTRANCE_GRID_S);
    const wallR = clamp01((t - ENTRANCE_WALL_DELAY_S) / ENTRANCE_WALL_S);
    for (const m of wallMats) m.uniforms.uReveal.value = wallR;
    if (t >= ENTRANCE_FX_START_S && !entranceFxCued) {
      entranceFxCued = true;
      fxStart();
    }
    fxDrive();
    if (t >= ENTRANCE_TOTAL_S) {
      if (!fx.isDone() && t < ENTRANCE_TOTAL_S + 0.5) return;
      fxForceFinish();
      entranceT0 = null;
      entranceDone = true;
      grid.material.uniforms.uReveal.value = 1;
      for (const m of wallMats) m.uniforms.uReveal.value = 1;
      setLocked(false);
      entranceFinishedResolve();
    }
  }

  function playRespawn() {
    if (!entranceDone) return;
    setLocked(true);
    flashReset();
    bind();
    startCameraReset();
    syncRig();
    fx.setProgress(0);
    respawn = { t0: performance.now(), scanCued: false };
  }

  function driveRespawn() {
    if (!respawn) return;
    const u = (performance.now() - respawn.t0) / 1000 / CAM_RESET_S;
    if (!respawn.scanCued && u >= RESPAWN_SCAN_AT) {
      respawn.scanCued = true;
      fxStart();
    }
    if (respawn.scanCued) fxDrive();
    if (respawn.scanCued && fx.isDone()) {
      respawn = null;
      setLocked(false);
    }
  }

  function drive() {
    driveEntrance();
    driveRespawn();
  }

  function setReveal(floor, wall = floor) {
    entranceT0 = null;
    grid.material.uniforms.uReveal.value = floor;
    for (const m of wallMats) m.uniforms.uReveal.value = wall;
  }

  function setFx(p) {
    entranceT0 = null;
    respawn = null;
    bind();
    if (p >= 1) {
      fx.start();
      fxForceFinish();
      setLocked(false);
      entranceFinishedResolve();
    } else {
      fx.setProgress(p);
    }
  }

  // Boot hidden: clip parked below the feet from the first frame.
  bind();

  return {
    CAM_RESET_S,
    startEntrance,
    playRespawn,
    drive,
    bind,
    setReveal,
    setFx,
    entranceFinished,
    get entranceDone() { return entranceDone; },
    get respawnActive() { return respawn !== null; },
  };
}