// The editor's visible texts, German and English (plan §7.5): English keys,
// the words in i18n/{de,en}.json — where Java FILIUS has a word for a thing,
// Java's (MessagesBundle), so that the terms on worksheets fit. The language
// comes from the dashboard over the bridge.

import { createContext, useContext, type ReactNode } from 'react';
import de from './de.json';
import en from './en.json';

export type Language = 'de' | 'en';
export const CATALOGS: Readonly<Record<Language, Readonly<Record<string, string>>>> = { de, en };

export type Translate = (key: string, values?: Readonly<Record<string, string | number>>) => string;

/** The text of a key in a language, its {placeholders} filled; the key itself where the catalog has none. */
export function translate(language: Language, key: string, values: Readonly<Record<string, string | number>> = {}): string {
  const text = CATALOGS[language][key] ?? key;
  return text.replace(/\{(\w+)\}/g, (whole, name: string) => (name in values ? String(values[name]) : whole));
}

const LanguageContext = createContext<Language>('de');

export function LanguageProvider({ language, children }: { readonly language: Language; readonly children: ReactNode }) {
  return <LanguageContext.Provider value={language}>{children}</LanguageContext.Provider>;
}

export function useLanguage(): Language {
  return useContext(LanguageContext);
}

export function useTranslate(): Translate {
  const language = useContext(LanguageContext);
  return (key, values) => translate(language, key, values);
}