/** Main-thread side of the classifier worker: one call per take, a fresh
 *  worker each time so a hung custom algorithm dies with its worker when
 *  the next classification starts. */
import type { ClfRequest, ClfResponse } from './algo.worker.ts';
import type { Detection, TrainingArrays } from './types.ts';

let current: Worker | null = null;
let nextId = 1;

export function classifyInWorker(
  source: string,
  x: Float32Array,
  fs: number,
  training: TrainingArrays,
): Promise<{ detections: Detection[]; logs: string[] }> {
  current?.terminate();
  const worker = new Worker(new URL('./algo.worker.ts', import.meta.url), { type: 'module' });
  current = worker;
  const id = nextId++;
  const req: ClfRequest = { id, source, x, fs, training };
  return new Promise((resolve, reject) => {
    worker.onmessage = (e: MessageEvent<ClfResponse>) => {
      if (e.data.id !== id) return;
      worker.terminate();
      if (current === worker) current = null;
      if (e.data.ok && e.data.detections) resolve({ detections: e.data.detections, logs: e.data.logs });
      else reject(new Error(e.data.error ?? 'classifier failed'));
    };
    worker.onerror = (e) => {
      worker.terminate();
      if (current === worker) current = null;
      reject(new Error(e.message || 'classifier worker failed'));
    };
    worker.postMessage(req);
  });
}