svelte-kit-vice/src/lib/ext/lang/lang.svelte.ts

import { createLang, type LangNode, type SupportedLocale, type LangInstance } from './lib';

export type { LangNode, SupportedLocale, LangInstance };

/**
 * Reactive wrapper around lang for Svelte 5.
 *
 * Mirrors the lang instance but overrides `getLocale` and `t` to touch
 * a `$state` variable, so any `$derived` / `$effect` that calls them
 * re-evaluates when the locale changes.
 */
export function createLangs<S extends LangNode>(
	schema: S,
	defaultLocale?: SupportedLocale,
	fallbackChain?: SupportedLocale[]
) {
	const lang = createLang(schema, defaultLocale, fallbackChain);

	let _locale = $state<SupportedLocale>(lang.getLocale());
	let _schemaVersion = $state(0);

	lang.onLocaleChange((locale) => {
		_locale = locale;
	});

	lang.onSchemaChange(() => {
		_schemaVersion++;
	});

	return {
		t(path: string, params?: Record<string, any>, locale?: SupportedLocale): string {
			void _locale;
			void _schemaVersion;
			return lang.t(path, params, locale);
		},

		ts(value: any, locale?: SupportedLocale): string {
			void _locale;
			void _schemaVersion;
			return lang.ts(value, locale);
		},

		getLocale(): SupportedLocale {
			return _locale;
		},

		setLocale(locale: SupportedLocale): void {
			lang.setLocale(locale);
		},

		extend(namespace: string, module: LangNode): void {
			lang.extend(namespace, module);
		},

		register<NS extends string, M extends LangNode>(namespace: NS, module: M) {
			return lang.register(namespace, module);
		},

		onLocaleChange(fn: (locale: SupportedLocale) => void): () => void {
			return lang.onLocaleChange(fn);
		},

		onSchemaChange(fn: () => void): () => void {
			return lang.onSchemaChange(fn);
		},

		setLogger(logger: any): void {
			lang.setLogger(logger);
		},

		dispose(): void {
			lang.dispose();
		},

		__dispose: lang.__dispose
	} as unknown as LangInstance<S>;
}