import fastGlob from 'fast-glob';
import watchGlob from 'glob-watcher';
import { Observable } from '../../observable';
import { resolve } from 'path';

type GlobOptions<T> = {
  cwd: string;
  pattern: string;
  create?: (path: string) => T;
};

const defaultCreate = (a: any) => a;

const createGlob = <T = string>({ cwd, pattern, create = defaultCreate }: GlobOptions<T>) => {
  const glob = new Observable(async () => {
    const files = await fastGlob(pattern, { cwd });
    return files.map((path) => create(resolve(cwd, path)));
  });

  const watcher = watchGlob(pattern, { cwd });
  watcher.on('add', (path) => {
    glob.set((current) => Promise.resolve([...(current || []), create(resolve(cwd, path))]));

    return glob;
  });

  return glob;
};

export { createGlob };