import assert from 'node:assert/strict';
import { describe, it } from 'node:test';
import { base32Decode, totp } from '../src/core/totp.ts';

/**
 * RFC 6238's own SHA-1 vectors, whose key is the ASCII string
 * "12345678901234567890" — base32 below. They validate the decode as much as
 * the code: a wrong base32 table would not reproduce a single one of them.
 */
const RFC_KEY = 'GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ';

describe('totp', () => {
	it('reproduces the RFC 6238 vectors', () => {
		// Each vector's 8-digit code, truncated to the 6 digits WebUntis wants.
		const vectors: [seconds: number, code: string][] = [
			[59, '287082'],
			[1_111_111_109, '081804'],
			[1_111_111_111, '050471'],
			[1_234_567_890, '005924'],
			[2_000_000_000, '279037'],
			[20_000_000_000, '353130'],
		];
		for (const [seconds, code] of vectors) {
			assert.equal(totp(RFC_KEY, seconds * 1000), code, `at ${seconds}s`);
		}
	});

	it('keeps a leading zero, which is why the code travels as a string', () => {
		const code = totp(RFC_KEY, 1_234_567_890_000);
		assert.equal(code, '005924');
		assert.equal(code.length, 6);
		// The bug this guards: sending the code as a JSON number would make it 5924.
		assert.notEqual(String(Number(code)), code);
	});

	it('changes with the 30-second step and not within it', () => {
		const base = 1_700_000_000_000;
		assert.equal(totp(RFC_KEY, base), totp(RFC_KEY, base + 29_000 - (base % 30_000)));
		assert.notEqual(totp(RFC_KEY, base), totp(RFC_KEY, base + 30_000));
	});
});

describe('base32Decode', () => {
	it('decodes to the bytes behind the RFC key', () => {
		assert.equal(base32Decode(RFC_KEY).toString('utf8'), '12345678901234567890');
	});

	it('accepts lowercase, padding and spaces, as a copied key arrives', () => {
		const expected = base32Decode('JBSWY3DP');
		assert.deepEqual(base32Decode('jbswy3dp'), expected);
		assert.deepEqual(base32Decode('JBSW Y3DP'), expected);
		assert.deepEqual(base32Decode('JBSWY3DP===='), expected);
	});

	it('refuses a value that is not base32 rather than deriving a wrong code', () => {
		assert.throws(() => base32Decode('nope!'), /outside A-Z and 2-7/);
		assert.throws(() => base32Decode('   '), /empty/);
	});
});