import { detectLocale, navigatorDetector, initLocalStorageDetector } from "typesafe-i18n/detectors";
import { FALLBACK_LOCALE } from "../Enum/EnvironmentVariable";
import { setLocale, locale } from "./i18n-svelte";
import type { Locales } from "./i18n-types";
import { baseLocale, locales } from "./i18n-util";
import { loadLocaleAsync } from "./i18n-util.async";
import { get } from "svelte/store";

const fallbackLocale = (FALLBACK_LOCALE || baseLocale) as Locales;
const localStorageProperty = "language";

export const localeDetector = async () => {
    const exist = localStorage.getItem(localStorageProperty);
    let detectedLocale: Locales = fallbackLocale;

    if (exist) {
        const localStorageDetector = initLocalStorageDetector(localStorageProperty);
        detectedLocale = detectLocale(fallbackLocale, locales, localStorageDetector);
    } else {
        detectedLocale = detectLocale(fallbackLocale, locales, navigatorDetector);
    }

    await setCurrentLocale(detectedLocale);
};

export const setCurrentLocale = async (locale: Locales) => {
    localStorage.setItem(localStorageProperty, locale);
    await loadLocaleAsync(locale);
    setLocale(locale);
};

export const displayableLocales: { id: Locales; language: string; region: string }[] = locales.map((locale) => {
    const [language, region] = locale.split("-");

    // backwards compatibility
    if (!Intl.DisplayNames) {
        return { id: locale, language, region };
    }

    return {
        id: locale,
        language: new Intl.DisplayNames(locale, { type: "language" }).of(language),
        region: new Intl.DisplayNames(locale, { type: "region" }).of(region),
    };
});

export const i18nJson = (text: string): string => {
    if (text.trim().startsWith("{")) {
        try {
            const textObject = JSON.parse(text);
            if (textObject[get(locale)]) {
                return textObject[get(locale)];
            } else if (Object.keys(textObject).length > 0) {
                // fallback to first value
                return textObject[Object.keys(textObject)[0]];
            }
        } catch (err) {
            //
        }
    }
    return text;
};