class ClassWriter

final class ClassWriter {
    
    /**
     * This class should not be instantiated.
     */
    private function __construct() {
    }
    
    /**
     * Mutates PHPUnit classes to make it compatible with Drupal.
     *
     * @param \Composer\Autoload\ClassLoader $autoloader
     *   The autoloader.
     *
     * @throws \ReflectionException
     */
    public static function mutateTestBase($autoloader) {
        static::alterAssert($autoloader);
        static::alterTestCase($autoloader);
    }
    
    /**
     * Alters the Assert class.
     *
     * @param \Composer\Autoload\ClassLoader $autoloader
     *   The autoloader.
     *
     * @throws \ReflectionException
     */
    private static function alterAssert(ClassLoader $autoloader) : void {
        // If the class exists already there is nothing we can do. Hopefully this
        // is happening because this has been called already. The call from
        // \Drupal\Core\Test\TestDiscovery::registerTestNamespaces() necessitates
        // this protection.
        if (class_exists('PHPUnit\\Framework\\Assert', FALSE)) {
            return;
        }
        // Mutate Assert code to make it forward compatible with different PhpUnit
        // versions, by adding Symfony's PHPUnit-bridge PolyfillAssertTrait.
        $alteredFile = $autoloader->findFile('PHPUnit\\Framework\\Assert');
        $phpunit_dir = dirname($alteredFile, 3);
        $alteredCode = file_get_contents($alteredFile);
        $alteredCode = preg_replace('/abstract class Assert[^\\{]+\\{/', '$0 ' . \PHP_EOL . "    use \\Symfony\\Bridge\\PhpUnit\\Legacy\\PolyfillAssertTrait;" . \PHP_EOL, $alteredCode, 1);
        include static::flushAlteredCodeToFile('Assert.php', $alteredCode);
    }
    
    /**
     * Alters the TestCase class.
     *
     * @param \Composer\Autoload\ClassLoader $autoloader
     *   The autoloader.
     *
     * @throws \ReflectionException
     */
    private static function alterTestCase(ClassLoader $autoloader) : void {
        // If the class exists already there is nothing we can do. Hopefully this
        // is happening because this has been called already. The call from
        // \Drupal\Core\Test\TestDiscovery::registerTestNamespaces() necessitates
        // this protection.
        if (class_exists('PHPUnit\\Framework\\TestCase', FALSE)) {
            return;
        }
        // Mutate TestCase code to make it forward compatible with different PhpUnit
        // versions, by adding Symfony's PHPUnit-bridge PolyfillTestCaseTrait.
        $alteredFile = $autoloader->findFile('PHPUnit\\Framework\\TestCase');
        $phpunit_dir = dirname($alteredFile, 3);
        $alteredCode = file_get_contents($alteredFile);
        $alteredCode = preg_replace('/abstract class TestCase[^\\{]+\\{/', '$0 ' . \PHP_EOL . "    use \\Symfony\\Bridge\\PhpUnit\\Legacy\\PolyfillTestCaseTrait;" . \PHP_EOL, $alteredCode, 1);
        $alteredCode = str_replace("__DIR__ . '/../Util/", "'{$phpunit_dir}/src/Util/", $alteredCode);
        // While Drupal still allows methods in test base classes that inherit from
        // TestCase with no void return typehints specified, we also alter TestCase
        // to remove the typehints.
        // @see https://www.drupal.org/project/drupal/issues/3182103
        $alteredCode = preg_replace('/^    ((?:protected|public)(?: static)? function \\w+\\(\\)): void/m', '    $1', $alteredCode);
        include static::flushAlteredCodeToFile('TestCase.php', $alteredCode);
    }
    
    /**
     * Flushes altered class code to file when necessary.
     *
     * @param string $file_name
     *   The file name.
     * @param string $altered_code
     *   The altered code.
     *
     * @return string
     *   The full path of the file to be included.
     */
    private static function flushAlteredCodeToFile(string $file_name, string $altered_code) : string {
        $directory = __DIR__ . '/../../../../../../sites/simpletest';
        $full_path = $directory . '/' . $file_name;
        // Only write when necessary.
        if (!file_exists($full_path) || md5_file($full_path) !== md5($altered_code)) {
            // Create directory when necessary.
            if (!is_dir($directory) && !@mkdir($directory, 0777, TRUE) && !is_dir($directory)) {
                throw new \RuntimeException('Unable to create directory: ' . $directory);
            }
            file_put_contents($full_path, $altered_code);
        }
        return $full_path;
    }

}