// PROCITY core loaders — promise-cached, fail-soft (house pattern from both parent games).
// Missing asset ⇒ null / flat colour; callers keep their placeholder. The game runs asset-free.

import * as THREE from 'three';
import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';

export const DEPOT = 'https://digalot.fyi/3god'; // shared GLB CDN: GET /a/<file>, /api/list

// Local-depot mode (Lane E round-3): resolve depot:<file> to GLBs served by the dev server
// (web/assets/models/) instead of the CDN, so Lanes B/C/F can validate GLB loading with NO
// network / before the depot publish. Enable per-load with ?localdepot=1 (or ?localdepot=<base>),
// or globally with window.PROCITY_LOCALDEPOT = true | '<base>'. Staged GLBs = the normalized
// library set + hero props (mirror of pipeline/_normalized; run pipeline/stage_local_depot.py).
export const LOCAL_MODELS = 'assets/models/';
function localDepotBase() {
  try {
    const q = new URLSearchParams(location.search).get('localdepot');
    if (q === '1' || q === '' || q === 'true') return LOCAL_MODELS;
    if (q) return q.endsWith('/') ? q : q + '/';
  } catch { /* no location (non-browser import) */ }
  const g = (typeof window !== 'undefined') && window.PROCITY_LOCALDEPOT;
  if (g === true) return LOCAL_MODELS;
  if (typeof g === 'string' && g) return g.endsWith('/') ? g : g + '/';
  return null;
}
const LOCAL_DEPOT = localDepotBase();
// resolve a depot:<file> ref to a concrete URL (local mode → served copy, else the CDN)
export function depotURL(file) {
  return LOCAL_DEPOT ? LOCAL_DEPOT + file : `${DEPOT}/a/${file}`;
}

const gltfLoader = new GLTFLoader();
const texLoader = new THREE.TextureLoader();
const GLB_CACHE = {};   // url → Promise<gltf|null>
const TEX_CACHE = {};   // url → THREE.Texture (may still be loading; fallback colour beneath)

// loadGLB('gen/x.glb' | 'depot:file.glb' | full URL) → Promise<gltf|null>, cached, never rejects
export function loadGLB(ref) {
  const url = ref.startsWith('depot:') ? depotURL(ref.slice(6)) : ref;
  return (GLB_CACHE[url] ||= gltfLoader.loadAsync(url).catch(err => {
    console.warn('[loaders] GLB failed, placeholder stays:', url, err?.message || err);
    return null;
  }));
}

// loadTex(url, {repeat:[u,v]}) → texture immediately (fills in when loaded), sRGB, aniso 4
export function loadTex(url, opts = {}) {
  if (TEX_CACHE[url]) return TEX_CACHE[url];
  const t = texLoader.load(url, undefined, undefined,
    () => console.warn('[loaders] tex failed, fallback colour stays:', url));
  t.colorSpace = THREE.SRGBColorSpace;
  t.anisotropy = 4;
  if (opts.repeat) { t.wrapS = t.wrapT = THREE.RepeatWrapping; t.repeat.set(...opts.repeat); }
  TEX_CACHE[url] = t;
  return t;
}

// fetch + cache the depot listing (editor palettes, Lane E validation)
let _depotList = null;
export async function depotList() {
  return (_depotList ||= fetch(`${DEPOT}/api/list`).then(r => r.json()).catch(() => []));
}