import { useEffect, useRef, useState, useCallback } from 'react';

// useEffect(() => {
// While History API does have `popstate` event, the only
// proper way to listen to changes via `push/replaceState`
// is to monkey-patch these methods.
//
// See https://stackoverflow.com/a/4585031
if (typeof history !== 'undefined') {
  for (const type of [eventPushState, eventReplaceState]) {
    const original = history[type];

    history[type] = function () {
      const result = original.apply(this, arguments);
      const event = new Event(type);
      event.arguments = arguments;

      dispatchEvent(event);
      return result;
    };
  }
} else {
  console.log('No history API');
}
// });

/**
 * History API docs @see https://developer.mozilla.org/en-US/docs/Web/API/History
 */
const eventPopstate = 'popstate';
const eventPushState = 'pushState';
const eventReplaceState = 'replaceState';
export const events = [eventPopstate, eventPushState, eventReplaceState];

const useLocation = ({ base = '' } = {}) => {
  const getCurrentPathname = useCallback(base => {
    const path = typeof location === 'undefined' ? '/' : location.pathname;

    return !path.toLowerCase().indexOf(base.toLowerCase())
      ? path.slice(base.length) || '/'
      : '~' + path;
  }, []);

  const [path, update] = useState(() => getCurrentPathname(base)); // @see https://reactjs.org/docs/hooks-reference.html#lazy-initial-state
  const prevPath = useRef(path);

  useEffect(() => {
    // this function checks if the location has been changed since the
    // last render and updates the state only when needed.
    // unfortunately, we can't rely on `path` value here, since it can be stale,
    // that's why we store the last pathname in a ref.
    const checkForUpdates = () => {
      const pathname = getCurrentPathname(base);
      console.log('CHECK FOR UPDATES', pathname);
      prevPath.current !== pathname && update((prevPath.current = pathname));
    };

    events.map(e => addEventListener(e, checkForUpdates));

    // it's possible that an update has occurred between render and the effect handler,
    // so we run additional check on mount to catch these updates. Based on:
    // https://gist.github.com/bvaughn/e25397f70e8c65b0ae0d7c90b731b189
    checkForUpdates();

    return () => events.map(e => removeEventListener(e, checkForUpdates));
  }, [base]);

  // the 2nd argument of the `useLocation` return value is a function
  // that allows to perform a navigation.
  //
  // the function reference should stay the same between re-renders, so that
  // it can be passed down as an element prop without any performance concerns.
  const navigate = useCallback(
    (to, { replace = false } = {}) =>
      history[replace ? eventReplaceState : eventPushState](
        null,
        '',
        // handle nested routers and absolute paths
        to[0] === '~' ? to.slice(1) : base + to
      ),
    [base]
  );

  return [path, navigate];
};
export default useLocation;