import { matchPath } from 'react-router-dom';
import { DIRECT_PATH, EXPLORE_PATH, HOME_PATH, INBOX_PATH, SPACE_PATH } from '../pages/paths';
import {
  getDirectPath,
  getExplorePath,
  getHomePath,
  getInboxPath,
  getSpacePath,
} from '../pages/pathUtils';

/**
 * Returns the section-root parent path for the given pathname, or null
 * when pathname is not under a known section or is already at the root
 * of its section. Shared by the UI back arrow (BackRouteHandler) and the
 * Android hardware back button (useAndroidBackButton) so they can't drift.
 */
export const getRouteSectionParent = (pathname: string): string | null => {
  const atRoot = (path: string) =>
    matchPath({ path, caseSensitive: true, end: true }, pathname) !== null;
  const under = (path: string) =>
    matchPath({ path, caseSensitive: true, end: false }, pathname) !== null;

  if (under(HOME_PATH)) return atRoot(HOME_PATH) ? null : getHomePath();
  if (under(DIRECT_PATH)) return atRoot(DIRECT_PATH) ? null : getDirectPath();

  const spaceMatch = matchPath({ path: SPACE_PATH, caseSensitive: true, end: false }, pathname);
  const encodedSpaceIdOrAlias = spaceMatch?.params.spaceIdOrAlias;
  if (encodedSpaceIdOrAlias) {
    const spacePath = getSpacePath(decodeURIComponent(encodedSpaceIdOrAlias));
    return pathname === spacePath ? null : spacePath;
  }

  if (under(EXPLORE_PATH)) return atRoot(EXPLORE_PATH) ? null : getExplorePath();
  if (under(INBOX_PATH)) return atRoot(INBOX_PATH) ? null : getInboxPath();

  return null;
};