import { describe, it, expect } from 'vitest';
import { relativeTimeDe, relativeYearsDe } from './relativeTime';

const NOW = new Date('2026-04-20T12:00:00Z');

describe('relativeTimeDe', () => {
	it('returns minutes for a gap under one hour', () => {
		const from = new Date('2026-04-20T11:58:00Z');
		expect(relativeTimeDe(from, NOW)).toContain('2');
		expect(relativeTimeDe(from, NOW)).toMatch(/Minute/i);
	});

	it('returns hours for a gap between 1 and 24 hours', () => {
		const from = new Date('2026-04-20T09:00:00Z');
		expect(relativeTimeDe(from, NOW)).toContain('3');
		expect(relativeTimeDe(from, NOW)).toMatch(/Stunde/i);
	});

	it('returns days for a gap of 24 hours or more', () => {
		const from = new Date('2026-04-18T12:00:00Z');
		expect(relativeTimeDe(from, NOW)).toContain('2');
		expect(relativeTimeDe(from, NOW)).toMatch(/Tag/i);
	});

	it('rounds minutes to the nearest whole number', () => {
		const from = new Date('2026-04-20T11:58:20Z');
		expect(relativeTimeDe(from, NOW)).toContain('2');
	});

	it('handles zero gap as 0 minutes', () => {
		expect(relativeTimeDe(NOW, NOW)).toMatch(/0/);
		expect(relativeTimeDe(NOW, NOW)).toMatch(/Minute/i);
	});

	it('falls back to 0 minutes when the input Date is invalid', () => {
		const invalid = new Date('not-a-real-date');
		// Never crash the UI if the backend ever ships a malformed uploadedAt.
		expect(relativeTimeDe(invalid, NOW)).toMatch(/0/);
		expect(relativeTimeDe(invalid, NOW)).toMatch(/Minute/i);
	});
});

describe('relativeYearsDe', () => {
	it('returns singular "vor 1 Jahr" for exactly one whole year ago', () => {
		const from = new Date('2025-04-20T12:00:00Z');
		expect(relativeYearsDe(from, NOW)).toBe('vor 1 Jahr');
	});

	it('returns plural "vor N Jahren" for more than one year', () => {
		const from = new Date('1940-04-20T12:00:00Z');
		expect(relativeYearsDe(from, NOW)).toBe('vor 86 Jahren');
	});

	it('floors a partial year down (eleven months ago = 0 years)', () => {
		const from = new Date('2025-06-01T00:00:00Z');
		// We show "vor weniger als 1 Jahr" rather than rounding up to 1.
		expect(relativeYearsDe(from, NOW)).toBe('vor weniger als 1 Jahr');
	});

	it('returns empty string when the input Date is invalid', () => {
		const invalid = new Date('not-a-real-date');
		expect(relativeYearsDe(invalid, NOW)).toBe('');
	});

	it('returns empty string for future dates', () => {
		const future = new Date('2030-01-01T00:00:00Z');
		expect(relativeYearsDe(future, NOW)).toBe('');
	});
});
