export function uid(prefix: string): string {
  return (
    prefix
    + Date.now().toString(36).substring(4)
    + Math.random().toString(36).substring(2)
  );
}

export function partition<T>(
  predicate: (acc: T, idx?: number, arr?: T[]) => boolean,
) {
  return function (subject: T[]): [T[], T[]] {
    return subject.reduce(
      (acc, val, idx, arr) => {
        acc[predicate(val, idx, arr) ? 0 : 1].push(val);
        return acc;
      },
      [[], []] as [T[], T[]],
    );
  };
}

export function toDataUrl(file: File | Blob): Promise<string> {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();
    reader.onerror = reject;
    reader.onload = () => {
      resolve(reader.result as string);
    };

    reader.readAsDataURL(file);
  });
}

function deferred(ms: number) {
  let cancel;

  const promise = new Promise((resolve, reject) => {
    cancel = reject;
    setTimeout(resolve, ms);
  });

  return { promise, cancel };
}

export function debounce(closure: Function, ms: number) {
  let t: any = { promise: null, cancel: (_ = undefined) => undefined };
  return [
    async (...args: unknown[]) => {
      try {
        t.cancel();
        t = deferred(ms);

        await t.promise;
        await closure(...args);
      }
      catch (_) { }
    },
    (_: unknown = undefined) => t.cancel(),
  ];
}