import { useRef, useCallback } from 'react';

// Guards async handlers against double-fire (e.g. a rapid double-click that triggers
// both onClick callbacks before React re-renders the now-disabled button). Disabled
// buttons alone don't prevent this because the disable only takes effect after a render.
//
// Usage:
//   const guard = useActionLock();
//   const handleSubmit = guard('submit', async () => { ... });
//
// Each `key` locks independently, so unrelated buttons don't block each other. While a
// run is in-flight the same key is a no-op until it settles (resolve or throw).
export function useActionLock() {
  const locks = useRef(new Set());
  return useCallback((key, fn) => async (...args) => {
    if (locks.current.has(key)) return undefined;
    locks.current.add(key);
    try {
      return await fn(...args);
    } finally {
      locks.current.delete(key);
    }
  }, []);
}