import type * as MSAWorker from './multi-sequence-alignment.worker';

const cache = new Map<string, string[]>();

function runInWorker(
  worker: Worker,
  message: MSAWorker.RequestMessage,
  signal: AbortSignal,
): Promise<MSAWorker.ResponseMessage> {
  return new Promise((resolve, reject) => {
    worker.addEventListener('message', ({ data }: MessageEvent<MSAWorker.ResponseMessage>) => {
      resolve(data);
      worker.terminate();
    });
    worker.addEventListener('error', ({ error, message: msg }: ErrorEvent) => {
      reject(error ?? msg);
      worker.terminate();
    });
    signal.addEventListener('abort', () => {
      reject(signal.reason);
      worker.terminate();
    });
    worker.postMessage(message);
  });
}

export async function alignSequences(
  sequences: string[],
  params = { gpo: 5.5, gpe: 2.0, tgpe: 1.0 },
  signal?: AbortSignal,
): Promise<string[]> {
  if (sequences.length < 2) return sequences;

  const key = JSON.stringify([sequences, params]);
  const cached = cache.get(key);
  if (cached) return cached;

  const result = await runInWorker(
    new Worker(new URL('./multi-sequence-alignment.worker.ts', import.meta.url), { type: 'module' }),
    { sequences, params },
    signal ?? new AbortController().signal,
  );

  if (!signal?.aborted) {
    cache.set(key, result);
  }
  return result;
}