/**
 * The path the site is served under: the editor, the play page, the API and every data file. It
 * is the folder of the open page, so one build answers at https://nockal.com/feuerwerk/ and at
 * https://feuerwerk.nockal.com/ alike. Away from a page (Node, the tests) it is the nginx path.
 */
export const SITE_PATH = sitePath(typeof location === 'undefined' ? undefined : location.pathname);

/** The folder of a page path: `/feuerwerk/play.html` and `/feuerwerk/` give `/feuerwerk/`. */
export function sitePath(pagePath: string | undefined): string {
  if (pagePath === undefined) return '/feuerwerk/';
  return pagePath.slice(0, pagePath.lastIndexOf('/') + 1);
}

/** The API's one entry point. */
export const API_ENDPOINT = `${SITE_PATH}api/index.php`;

/** Where the uploaded files of one kind are served, e.g. `dataPath('textures')`. */
export function dataPath(kind: string): string {
  return `${SITE_PATH}data/${kind}`;
}

/** The prefix of every `localStorage` key while the editor was called Game Maker. */
const OLD_KEY_PREFIX = 'game-maker.';
const KEY_PREFIX = 'feuerwerk.';

type KeyStore = Pick<Storage, 'length' | 'key' | 'getItem' | 'setItem' | 'removeItem'>;

/**
 * Moves what a browser kept under the old name to the new one: settings, panel sizes, folds and
 * saves survive the rename. A key the new name already has keeps its value. Answers how many moved.
 */
export function moveOldStoredKeys(storage: KeyStore): number {
  const old: string[] = [];
  for (let i = 0; i < storage.length; i++) {
    const key = storage.key(i);
    if (key?.startsWith(OLD_KEY_PREFIX)) old.push(key);
  }
  let moved = 0;
  for (const key of old) {
    const value = storage.getItem(key);
    const renamed = KEY_PREFIX + key.slice(OLD_KEY_PREFIX.length);
    if (value !== null && storage.getItem(renamed) === null) {
      storage.setItem(renamed, value);
      moved++;
    }
    storage.removeItem(key);
  }
  return moved;
}