import * as THREE from "three";

// Each viewer owns its textures. Browser HTTP caching handles repeat downloads;
// keeping GPU resources in a global cache leaks every visited map and signed URL.
export async function loadPanoramaTextures(
  urls: string[],
  loader: Pick<THREE.TextureLoader, "loadAsync"> = new THREE.TextureLoader(),
  timeoutMs = 30000,
): Promise<THREE.Texture[]> {
  const textures: THREE.Texture[] = [];
  let failed = false;
  let timer: ReturnType<typeof setTimeout> | undefined;
  try {
    return await Promise.race([
      Promise.all(
        urls.map(async (url) => {
          const texture = await loader.loadAsync(url);
          if (failed) {
            texture.dispose();
            throw new Error("Panorama loading cancelled");
          }
          texture.colorSpace = THREE.SRGBColorSpace;
          textures.push(texture);
          return texture;
        }),
      ),
      new Promise<never>((_, reject) => {
        timer = setTimeout(
          () =>
            reject(
              new Error("Panorama loading timed out. Reconnect to retry."),
            ),
          timeoutMs,
        );
      }),
    ]);
  } catch (error) {
    failed = true;
    textures.forEach((texture) => texture.dispose());
    throw error;
  } finally {
    clearTimeout(timer);
  }
}