// PROCITY Lane D — R41 §41.3: THE CLIP BANK. Lane E's 46-clip motion library, loaded by group,
// lazily, fail-soft, and byte-shaped exactly like the eight clips `loadPedFleet` already loads.
//
// The contract (Lane E, `web/assets/motion_manifest.json`, E-progress §41.1 ¶4):
//   groups[<file>]      one GLB under web/models/clips/ = ONE fetch, N named animations
//   clips[<clipId>]     { group, category, duration, loopable, loopSeamDeg, source, mixamo, … }
//   a group GLB's gltf.animations[] are NAMED BY clipId ⇒ `animations.find(a => a.name === id)`
//
// Verified before wiring, not assumed: `python3 pipeline/clips_verify.py` → GREEN 0/0 on today's
// tree, 46 clips / 6 groups / 3 498 124 B, every group 0 meshes / 0 materials / 0 images / 66 nodes.
//
// This module is DYNAMICALLY imported by rigs.js, and only when the clip gate is on. That is not
// cosmetic: under `?classic=1` / `?noassets=1` the browser never fetches clipbank.js itself, so the
// zero-fetch-delta covenant holds for the JS surface as well as the asset surface.
//
// Loading is per GROUP and lazy by design (the fetch ledger is in LANE_D_NOTES §41):
//   boot     idles.glb + locomotion.glb + the manifest  (3 fetches, 1 258 784 B)
//   lazy     sitlean.glb on the first sit/lean intent · browse.glb on the first interior browser ·
//            venue.glb on the first gig / pub / record-shop keeper
//   never    social.glb — no two-person state machine yet (R42)
// A clip that has not landed yet is simply absent: every consumer falls back to the pre-R41 8-clip
// action, so lazy loading can never change WHICH posture a citizen was assigned (postures.js), only
// how soon it looks like it.

import { loadGLB } from '../core/loaders.js';
import { canonName, rotOnlyClip } from './rigs.js';

export const CLIP_BASE = 'models/clips/';
export const MANIFEST_URL = 'assets/motion_manifest.json';
// Above this measured first-key→last-key seam a clip does not close, so repeating it pops. E measures
// `loopSeamDeg` per clip; we ping-pong those instead of dropping them — which is why `browse_pick_up`
// (92.15°) reads as crate-digging (down, up, down) rather than a teleport back to the start.
export const LOOP_SEAM_DEG = 25;

export class ClipBank {
  constructor({ clipBase = CLIP_BASE, manifestUrl = MANIFEST_URL } = {}) {
    this.clipBase = clipBase;
    this.manifestUrl = manifestUrl;
    this.manifest = null;
    this.clips = new Map();      // clipId → AnimationClip, already _canon'd + _rotOnly'd
    this.groups = new Map();     // group file → Promise<boolean>  (promise-cached: one fetch each)
    this.loaded = new Set();     // group files whose animations are indexed
    this.bytes = 0;              // manifest-declared bytes of the groups actually resident
    this._mp = null;
  }

  // boot(groups) — the manifest and the eager groups IN PARALLEL. Deliberately not serialised:
  // the group filenames are static (postures.js BOOT_GROUPS), so waiting for a 16 KB JSON before
  // starting a 1 MB GLB would add a round trip to the boot for nothing.
  boot(groups = []) {
    return Promise.all([this.manifestP(), ...groups.map((g) => this.ensureGroup(g))]).then(() => this);
  }

  manifestP() {
    return (this._mp ||= fetch(this.manifestUrl)
      .then((r) => (r.ok ? r.json() : null))
      .catch(() => null)
      .then((m) => { this.manifest = m || null; return this.manifest; }));
  }

  // ensureGroup(file) → Promise<boolean>. Promise-cached per file (and loadGLB is URL-cached under
  // that), so N callers racing on the first interior cost exactly one fetch. Fail-soft: a missing or
  // broken group resolves false and every consumer keeps its fallback clip.
  ensureGroup(file) {
    if (!file) return Promise.resolve(false);
    let p = this.groups.get(file);
    if (p) return p;
    p = loadGLB(this.clipBase + file).then((g) => {
      const anims = (g && g.animations) || [];
      if (!anims.length) return false;
      for (const a of anims) {
        if (this.clips.has(a.name)) continue;
        // the same two-step every shared clip in this project rides: fold mixamorigN: → mixamorig:
        // so any clip binds to any character, then keep rotations only (rigs.js `_rotOnly` — drops
        // every position/scale track AND Hips.quaternion). E measured 65 raw tracks → 64 after, on
        // all 46; asserted again below so a future re-pack that breaks it fails loudly here.
        a.tracks.forEach((t) => { t.name = canonName(t.name); });
        const c = rotOnlyClip(a);
        c.name = a.name;
        if (!c.tracks.length) { console.warn('[clipbank] clip empty after _rotOnly, skipped:', a.name); continue; }
        this.clips.set(a.name, c);
      }
      this.loaded.add(file);
      const gm = this.manifest && this.manifest.groups && this.manifest.groups[file];
      if (gm && gm.bytes) this.bytes += gm.bytes;
      return true;
    });
    this.groups.set(file, p);
    return p;
  }

  // get(id) → AnimationClip | null. Null is a first-class answer: "assigned, not resident yet".
  get(id) {
    if (!id || id[0] === '@') return null;      // '@…' are the pre-R41 base-asset sentinels
    const c = this.clips.get(id);
    if (!c) return null;
    // loop mode is decided ONCE, and only when the manifest is actually there to decide it from —
    // otherwise a clip that resolved before the JSON would be frozen on the default forever.
    if (c._pcLoop === undefined && this.manifest && this.manifest.clips) {
      const m = this.manifest.clips[id];
      c._pcLoop = (m && !m.loopable && (m.loopSeamDeg || 0) > LOOP_SEAM_DEG) ? 'pingpong' : 'repeat';
    }
    return c;
  }
  has(id) { return !!(id && id[0] !== '@' && this.clips.has(id)); }
  meta(id) { return (this.manifest && this.manifest.clips && this.manifest.clips[id]) || null; }

  // resolve a whole posture set at once; missing entries come back null (⇒ base-clip fallback)
  resolve(p) {
    return p ? { idle: this.get(p.idle), walk: this.get(p.walk), sit: this.get(p.sit), lean: this.get(p.lean) } : null;
  }

  stats() {
    return {
      groups: this.loaded.size, groupList: [...this.loaded].sort(),
      clips: this.clips.size, bytes: this.bytes,
      manifest: !!this.manifest,
      catalogue: this.manifest ? this.manifest.clipCount : 0,
    };
  }

  // AnimationClips hold NO GPU resources (these groups are 0 meshes / 0 materials / 0 images — E's
  // glb_stat + clips_verify both assert it), so there is nothing to free but the references. The
  // parsed gltf stays in core/loaders' URL cache exactly like every other GLB in the game.
  dispose() { this.clips.clear(); this.groups.clear(); this.loaded.clear(); this.bytes = 0; }
}
// NOTE on imports, on purpose: nothing outside rigs.js imports this module STATICALLY. rigs.js
// reaches it with a dynamic `import()` behind the clip gate, and every other consumer (sim, keepers,
// band) touches it only through the live `fleet.bank` object. So `?classic=1` / `?noassets=1` fetch
// neither the clip GLBs nor this file — the zero-fetch-delta covenant holds on the JS surface too.