<?php

use PHPUnit\Framework\TestCase;
use XcVm\Core\Config\OpensslExtra;
use XcVm\Core\Util\Encryption;

/**
 * Encryption::readToken — after a node is moved onto MAIN's OPENSSL_EXTRA,
 * the tokens it minted with the value it replaced (HLS segment and key links,
 * VOD links reused for seeks) keep opening until the replaced value's window
 * closes. Only the OPENSSL_EXTRA context falls back, and only a token that
 * fails with the current value tries it.
 *
 * tests/bootstrap.php defines OPENSSL_EXTRA as 'test-openssl-extra'.
 */
final class EncryptionPreviousExtraTest extends TestCase {

	private const PLAIN = 'live/user/pass/1/ts';

	private string $rFile;

	protected function setUp(): void {
		$this->rFile = sys_get_temp_dir() . '/xcvm_openssl_extra_prev_' . uniqid();
		OpensslExtra::usePrevFile($this->rFile);
	}

	protected function tearDown(): void {
		try {
			OpensslExtra::usePrevFile(null);
		} finally {
			@unlink($this->rFile);
		}
	}

	private function previous(string $rValue, int $rValidUntil): void {
		file_put_contents($this->rFile, json_encode(['value' => $rValue, 'valid_until' => $rValidUntil]));
		OpensslExtra::usePrevFile($this->rFile);
	}

	public function testATokenMintedWithTheReplacedValueOpensOnlyWhileItIsAccepted(): void {
		$rToken = Encryption::seal(self::PLAIN, 'k', 'old-extra');
		$this->assertFalse(Encryption::readToken($rToken, 'k', OPENSSL_EXTRA, false), 'no previous value');

		$this->previous('old-extra', time() + 600);
		$this->assertSame(self::PLAIN, Encryption::readToken($rToken, 'k', OPENSSL_EXTRA, false));

		$this->previous('old-extra', time() - 1);
		$this->assertFalse(Encryption::readToken($rToken, 'k', OPENSSL_EXTRA, false), 'window closed');
	}

	public function testALegacyTokenFallsBackOnlyWhereLegacyTokensAreAccepted(): void {
		$rToken = Encryption::encrypt(self::PLAIN, 'k', 'old-extra');
		$this->previous('old-extra', time() + 600);

		$this->assertSame(self::PLAIN, Encryption::readToken($rToken, 'k', OPENSSL_EXTRA, true));
		$this->assertFalse(Encryption::readToken($rToken, 'k', OPENSSL_EXTRA, false));
	}

	/**
	 * Where legacy tokens are accepted, a sealed token minted with the replaced
	 * value must not be read as a legacy one with the current value first: that
	 * decrypt() returns garbage instead of false about once in 256 tokens (when
	 * the padding happens to hold). 48- and 64-byte tokens can pass CBC's length
	 * check; 2000 of them miss none only when both sealed attempts come first.
	 */
	public function testASealedTokenWithTheReplacedValueOpensWhereLegacyTokensAreAccepted(): void {
		$this->previous('old-extra', time() + 600);

		$rMissed = 0;
		for ($i = 0; $i < 2000; $i++) {
			$rPlain = str_pad('live/' . $i . '/', ($i % 2) ? 20 : 36, 'x');
			if (Encryption::readToken(Encryption::seal($rPlain, 'k', 'old-extra'), 'k', OPENSSL_EXTRA, true) !== $rPlain) {
				$rMissed++;
			}
		}
		$this->assertSame(0, $rMissed);
	}

	public function testOnlyTheOpensslExtraContextFallsBack(): void {
		$this->previous('old-extra', time() + 600);

		$this->assertFalse(Encryption::readToken(Encryption::seal(self::PLAIN, 'k', 'old-extra'), 'k', 'd', false));
		$this->assertFalse(Encryption::readToken(Encryption::encrypt(self::PLAIN, 'k', 'old-extra'), 'k', 'd', true));
		$this->assertFalse(Encryption::readToken(Encryption::seal(self::PLAIN, 'other-key', OPENSSL_EXTRA), 'k', OPENSSL_EXTRA, false), 'another key is still refused');
	}

	public function testATokenMintedWithTheCurrentValueStillOpens(): void {
		$rSealed = Encryption::mintToken(self::PLAIN, 'k', OPENSSL_EXTRA, true);
		$rLegacy = Encryption::mintToken(self::PLAIN, 'k', OPENSSL_EXTRA, false);

		$this->assertSame(self::PLAIN, Encryption::readToken($rSealed, 'k', OPENSSL_EXTRA, false));
		$this->assertSame(self::PLAIN, Encryption::readToken($rLegacy, 'k', OPENSSL_EXTRA, true));

		$this->previous('old-extra', time() + 600);
		$this->assertSame(self::PLAIN, Encryption::readToken($rSealed, 'k', OPENSSL_EXTRA, false));
		$this->assertSame(self::PLAIN, Encryption::readToken($rLegacy, 'k', OPENSSL_EXTRA, true));
	}
}