import { Metadata } from "@readium/shared";
export type ScriptMode = 'ltr' | 'rtl' | 'cjk-horizontal' | 'cjk-vertical' | 'mongolian-vertical';
/**
 * Derives the script mode from publication metadata.
 *
 * Rules:
 * - Only the first language in the array is used. A Latin book containing
 *   some Japanese is still Latin.
 * - For CJK (zh/ja/ko): both language AND explicit reading progression are
 *   required. CJK vertical = explicit rtl + CJK language. CJK horizontal =
 *   CJK language with ltr or unset progression.
 * - For RTL (ar/fa/he): language wins. If the primary language is a RTL
 *   script, RTL mode is applied regardless of the explicit progression
 *   direction declared in the OPF.
 * - For Mongolian (mn): Traditional Mongolian script (mn-Mong) uses
 *   writing-mode: vertical-lr. Cyrillic Mongolian (mn-Cyrl) is standard LTR.
 *   An explicit script subtag is required; bare `mn` defaults to LTR.
 */
export declare function getScriptMode(metadata: Metadata): ScriptMode;