import { describe, expect, it } from 'vitest';
import { createActiveNumbers } from '../active-numbers.svelte';

describe('createActiveNumbers()', () => {
	it('syncs locale source changes and notifies active listeners', () => {
		let locale = 'en-US';
		let listener: ((locale: string) => void) | undefined;
		const source = {
			getLocale: () => locale,
			onLocaleChange(fn: (nextLocale: string) => void) {
				listener = fn;
				return () => {
					listener = undefined;
				};
			}
		};
		const nums = createActiveNumbers({ localeSource: source });
		const localeChanges: string[] = [];
		let preferenceChanges = 0;

		nums.onLocaleChange((nextLocale) => localeChanges.push(nextLocale));
		nums.onPreferenceChange(() => {
			preferenceChanges++;
		});

		locale = 'de-DE';
		listener?.(locale);

		expect(nums.getLocale()).toBe('de-DE');
		expect(nums.getDecimalSeparator()).toBe(',');
		expect(localeChanges).toEqual(['de-DE']);
		expect(preferenceChanges).toBe(1);

		nums.setGrouping(false);
		expect(nums.getGrouping()).toBe(false);
		expect(preferenceChanges).toBe(2);

		nums.dispose();
		expect(listener).toBeUndefined();
	});
});