class BuildTestBase

abstract class BuildTestBase extends TestCase {
    use ExternalCommandRequirementsTrait;
    use PhpunitCompatibilityTrait;
    
    /**
     * The working directory where this test will manipulate files.
     *
     * Use getWorkspaceDirectory() to access this information.
     *
     * @var string
     *
     * @see self::getWorkspaceDirectory()
     */
    private $workspaceDir;
    
    /**
     * The process that's running the HTTP server.
     *
     * @var \Symfony\Component\Process\Process
     *
     * @see self::standUpServer()
     * @see self::stopServer()
     */
    private $serverProcess = NULL;
    
    /**
     * Default to destroying build artifacts after a test finishes.
     *
     * Mainly useful for debugging.
     *
     * @var bool
     */
    protected $destroyBuild = TRUE;
    
    /**
     * The docroot for the server process.
     *
     * This stores the last docroot directory used to start the server process. We
     * keep this information so we can restart the server if the desired docroot
     * changes.
     *
     * @var string
     */
    private $serverDocroot = NULL;
    
    /**
     * Our native host name, used by PHP when it starts up the server.
     *
     * Requests should always be made to 'localhost', and not this IP address.
     *
     * @var string
     */
    private static $hostName = '127.0.0.1';
    
    /**
     * Port that will be tested.
     *
     * Generated internally. Use getPortNumber().
     *
     * @var int
     */
    private $hostPort;
    
    /**
     * A list of ports used by the test.
     *
     * Prevent the same process finding the same port by storing a list of ports
     * already discovered. This also stores locks so they are not released until
     * the test class is torn down.
     *
     * @var \Symfony\Component\Lock\LockInterface[]
     */
    private $portLocks = [];
    
    /**
     * The Mink session manager.
     *
     * @var \Behat\Mink\Mink
     */
    private $mink;
    
    /**
     * The most recent command process.
     *
     * @var \Symfony\Component\Process\Process
     *
     * @see ::executeCommand()
     */
    private $commandProcess;
    
    /**
     * {@inheritdoc}
     */
    public static function setUpBeforeClass() {
        parent::setUpBeforeClass();
        static::checkClassCommandRequirements();
    }
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() {
        parent::setUp();
        static::checkMethodCommandRequirements($this->getName());
        $this->phpFinder = new PhpExecutableFinder();
        // Set up the workspace directory.
        // @todo Glean working directory from env vars, etc.
        $fs = new SymfonyFilesystem();
        $this->workspaceDir = $fs->tempnam(DrupalFilesystem::getOsTemporaryDirectory(), '/build_workspace_' . md5($this->getName() . microtime(TRUE)));
        $fs->remove($this->workspaceDir);
        $fs->mkdir($this->workspaceDir);
        $this->initMink();
    }
    
    /**
     * {@inheritdoc}
     */
    protected function tearDown() {
        parent::tearDown();
        $this->stopServer();
        foreach ($this->portLocks as $lock) {
            $lock->release();
        }
        $ws = $this->getWorkspaceDirectory();
        $fs = new SymfonyFilesystem();
        if ($this->destroyBuild && $fs->exists($ws)) {
            // Filter out symlinks as chmod cannot alter them.
            $finder = new Finder();
            $finder->in($ws)
                ->directories()
                ->ignoreVCS(FALSE)
                ->ignoreDotFiles(FALSE)
                ->notPath('/^vendor\\/bin\\/composer$/');
            $fs->chmod($finder->getIterator(), 0775, 00);
            $fs->remove($ws);
        }
    }
    
    /**
     * Get the working directory within the workspace, creating if necessary.
     *
     * @param string $working_dir
     *   The path within the workspace directory.
     *
     * @return string
     *   The full path to the working directory within the workspace directory.
     */
    protected function getWorkingPath($working_dir = NULL) {
        $full_path = $this->getWorkspaceDirectory();
        if ($working_dir) {
            $full_path .= '/' . $working_dir;
        }
        if (!file_exists($full_path)) {
            $fs = new SymfonyFilesystem();
            $fs->mkdir($full_path);
        }
        return $full_path;
    }
    
    /**
     * Set up the Mink session manager.
     *
     * @return \Behat\Mink\Session
     */
    protected function initMink() {
        // If the Symfony BrowserKit client can followMetaRefresh(), we should use
        // the Goutte descendent instead of ours.
        if (method_exists(SymfonyClient::class, 'followMetaRefresh')) {
            $client = new Client();
        }
        else {
            $client = new DrupalMinkClient();
        }
        $client->followMetaRefresh(TRUE);
        $driver = new GoutteDriver($client);
        $session = new Session($driver);
        $this->mink = new Mink();
        $this->mink
            ->registerSession('default', $session);
        $this->mink
            ->setDefaultSessionName('default');
        $session->start();
        return $session;
    }
    
    /**
     * Get the Mink instance.
     *
     * Use the Mink object to perform assertions against the content returned by a
     * request.
     *
     * @return \Behat\Mink\Mink
     *   The Mink object.
     */
    public function getMink() {
        return $this->mink;
    }
    
    /**
     * Full path to the workspace where this test can build.
     *
     * This is often a directory within the system's temporary directory.
     *
     * @return string
     *   Full path to the workspace where this test can build.
     */
    public function getWorkspaceDirectory() {
        return $this->workspaceDir;
    }
    
    /**
     * Assert that text is present in the error output of the most recent command.
     *
     * @param string $expected
     *   Text we expect to find in the error output of the command.
     */
    public function assertErrorOutputContains($expected) {
        $this->assertStringContainsString($expected, $this->commandProcess
            ->getErrorOutput());
    }
    
    /**
     * Assert that text is present in the output of the most recent command.
     *
     * @param string $expected
     *   Text we expect to find in the output of the command.
     */
    public function assertCommandOutputContains($expected) {
        $this->assertStringContainsString($expected, $this->commandProcess
            ->getOutput());
    }
    
    /**
     * Asserts that the last command ran without error.
     *
     * This assertion checks whether the last command returned an exit code of 0.
     *
     * If you need to assert a different exit code, then you can use
     * executeCommand() and perform a different assertion on the process object.
     */
    public function assertCommandSuccessful() {
        return $this->assertCommandExitCode(0);
    }
    
    /**
     * Asserts that the last command returned the specified exit code.
     *
     * @param int $expected_code
     *   The expected process exit code.
     */
    public function assertCommandExitCode($expected_code) {
        $this->assertEquals($expected_code, $this->commandProcess
            ->getExitCode(), 'COMMAND: ' . $this->commandProcess
            ->getCommandLine() . "\n" . 'OUTPUT: ' . $this->commandProcess
            ->getOutput() . "\n" . 'ERROR: ' . $this->commandProcess
            ->getErrorOutput() . "\n");
    }
    
    /**
     * Run a command.
     *
     * @param string $command_line
     *   A command line to run in an isolated process.
     * @param string $working_dir
     *   (optional) A working directory relative to the workspace, within which to
     *   execute the command. Defaults to the workspace directory.
     *
     * @return \Symfony\Component\Process\Process
     */
    public function executeCommand($command_line, $working_dir = NULL) {
        $this->commandProcess = new Process($command_line);
        $this->commandProcess
            ->setWorkingDirectory($this->getWorkingPath($working_dir))
            ->setTimeout(300)
            ->setIdleTimeout(300);
        $this->commandProcess
            ->run();
        return $this->commandProcess;
    }
    
    /**
     * Helper function to assert that the last visit was a Drupal site.
     *
     * This method asserts that the X-Generator header shows that the site is a
     * Drupal site.
     */
    public function assertDrupalVisit() {
        $this->getMink()
            ->assertSession()
            ->responseHeaderMatches('X-Generator', '/Drupal \\d+ \\(https:\\/\\/www.drupal.org\\)/');
    }
    
    /**
     * Visit a URI on the HTTP server.
     *
     * The concept here is that there could be multiple potential docroots in the
     * workspace, so you can use whichever ones you want.
     *
     * @param string $request_uri
     *   (optional) The non-host part of the URL. Example: /some/path?foo=bar.
     *   Defaults to visiting the homepage.
     * @param string $working_dir
     *   (optional) Relative path within the test workspace file system that will
     *   be the docroot for the request. Defaults to the workspace directory.
     *
     * @return \Behat\Mink\Mink
     *   The Mink object. Perform assertions against this.
     *
     * @throws \InvalidArgumentException
     *   Thrown when $request_uri does not start with a slash.
     */
    public function visit($request_uri = '/', $working_dir = NULL) {
        if ($request_uri[0] !== '/') {
            throw new \InvalidArgumentException('URI: ' . $request_uri . ' must be relative. Example: /some/path?foo=bar');
        }
        // Try to make a server.
        $this->standUpServer($working_dir);
        $request = 'http://localhost:' . $this->getPortNumber() . $request_uri;
        $this->mink
            ->getSession()
            ->visit($request);
        return $this->mink;
    }
    
    /**
     * Makes a local test server using PHP's internal HTTP server.
     *
     * Test authors should call visit() or assertVisit() instead.
     *
     * @param string|null $working_dir
     *   (optional) Server docroot relative to the workspace file system. Defaults
     *   to the workspace directory.
     */
    protected function standUpServer($working_dir = NULL) {
        // If the user wants to test a new docroot, we have to shut down the old
        // server process and generate a new port number.
        if ($working_dir !== $this->serverDocroot && !empty($this->serverProcess)) {
            $this->stopServer();
        }
        // If there's not a server at this point, make one.
        if (!$this->serverProcess || $this->serverProcess
            ->isTerminated()) {
            $this->serverProcess = $this->instantiateServer($this->getPortNumber(), $working_dir);
            if ($this->serverProcess) {
                $this->serverDocroot = $working_dir;
            }
        }
    }
    
    /**
     * Do the work of making a server process.
     *
     * Test authors should call visit() or assertVisit() instead.
     *
     * When initializing the server, if '.ht.router.php' exists in the root, it is
     * leveraged. If testing with a version of Drupal before 8.5.x., this file
     * does not exist.
     *
     * @param int $port
     *   The port number for the server.
     * @param string|null $working_dir
     *   (optional) Server docroot relative to the workspace filesystem. Defaults
     *   to the workspace directory.
     *
     * @return \Symfony\Component\Process\Process
     *   The server process.
     *
     * @throws \RuntimeException
     *   Thrown if we were unable to start a web server.
     */
    protected function instantiateServer($port, $working_dir = NULL) {
        $finder = new PhpExecutableFinder();
        $working_path = $this->getWorkingPath($working_dir);
        $server = [
            $finder->find(),
            '-S',
            self::$hostName . ':' . $port,
            '-t',
            $working_path,
        ];
        if (file_exists($working_path . DIRECTORY_SEPARATOR . '.ht.router.php')) {
            $server[] = $working_path . DIRECTORY_SEPARATOR . '.ht.router.php';
        }
        $ps = new Process($server, $working_path);
        $ps->setIdleTimeout(30)
            ->setTimeout(30)
            ->start();
        // Wait until the web server has started. It is started if the port is no
        // longer available.
        for ($i = 0; $i < 1000; $i++) {
            if (!$this->checkPortIsAvailable($port)) {
                return $ps;
            }
            usleep(1000);
        }
        throw new \RuntimeException(sprintf("Unable to start the web server.\nERROR OUTPUT:\n%s", $ps->getErrorOutput()));
    }
    
    /**
     * Stop the HTTP server, zero out all necessary variables.
     */
    protected function stopServer() {
        if (!empty($this->serverProcess)) {
            $this->serverProcess
                ->stop();
        }
        $this->serverProcess = NULL;
        $this->serverDocroot = NULL;
        $this->hostPort = NULL;
        $this->initMink();
    }
    
    /**
     * Discover an available port number.
     *
     * @return int
     *   The available port number that we discovered.
     *
     * @throws \RuntimeException
     *   Thrown when there are no available ports within the range.
     */
    protected function findAvailablePort() {
        $store = new FlockStore(DrupalFilesystem::getOsTemporaryDirectory());
        $lock_factory = new Factory($store);
        $counter = 100;
        while ($counter--) {
            // Limit to 9999 as higher ports cause random fails on DrupalCI.
            $port = random_int(1024, 9999);
            if (isset($this->portLocks[$port])) {
                continue;
            }
            // Take a lock so that no other process can use the same port number even
            // if the server is yet to start.
            $lock = $lock_factory->createLock('drupal-build-test-port-' . $port);
            if ($lock->acquire()) {
                if ($this->checkPortIsAvailable($port)) {
                    $this->portLocks[$port] = $lock;
                    return $port;
                }
                else {
                    $lock->release();
                }
            }
        }
        throw new \RuntimeException('Unable to find a port available to run the web server.');
    }
    
    /**
     * Checks whether a port is available.
     *
     * @param $port
     *   A number between 1024 and 65536.
     *
     * @return bool
     */
    protected function checkPortIsAvailable($port) {
        $fp = @fsockopen(self::$hostName, $port, $errno, $errstr, 1);
        // If fsockopen() fails to connect, probably nothing is listening.
        // It could be a firewall but that's impossible to detect, so as a
        // best guess let's return it as available.
        if ($fp === FALSE) {
            return TRUE;
        }
        else {
            fclose($fp);
        }
        return FALSE;
    }
    
    /**
     * Get the port number for requests.
     *
     * Test should never call this. Used by standUpServer().
     *
     * @return int
     */
    protected function getPortNumber() {
        if (empty($this->hostPort)) {
            $this->hostPort = $this->findAvailablePort();
        }
        return $this->hostPort;
    }
    
    /**
     * Copy the current working codebase into a workspace.
     *
     * Use this method to copy the current codebase, including any patched
     * changes, into the workspace.
     *
     * By default, the copy will exclude sites/default/settings.php,
     * sites/default/files, and vendor/. Use the $iterator parameter to override
     * this behavior.
     *
     * @param \Iterator|null $iterator
     *   (optional) An iterator of all the files to copy. Default behavior is to
     *   exclude site-specific directories and files.
     * @param string|null $working_dir
     *   (optional) Relative path within the test workspace file system that will
     *   contain the copy of the codebase. Defaults to the workspace directory.
     */
    public function copyCodebase(\Iterator $iterator = NULL, $working_dir = NULL) {
        $working_path = $this->getWorkingPath($working_dir);
        if ($iterator === NULL) {
            $iterator = $this->getCodebaseFinder()
                ->getIterator();
        }
        $fs = new SymfonyFilesystem();
        $options = [
            'override' => TRUE,
            'delete' => FALSE,
        ];
        $fs->mirror($this->getDrupalRoot(), $working_path, $iterator, $options);
    }
    
    /**
     * Get a default Finder object for a Drupal codebase.
     *
     * This method can be used two ways:
     * - Override this method and provide your own default Finder object for
     *   copyCodebase().
     * - Call the method to get a default Finder object which can then be
     *   modified for other purposes.
     *
     * @return \Symfony\Component\Finder\Finder
     *   A Finder object ready to iterate over core codebase.
     */
    public function getCodebaseFinder() {
        $finder = new Finder();
        $finder->files()
            ->ignoreUnreadableDirs()
            ->in($this->getDrupalRoot())
            ->notPath('#^sites/default/files#')
            ->notPath('#^sites/simpletest#')
            ->notPath('#^vendor#')
            ->notPath('#^sites/default/settings\\..*php#')
            ->ignoreDotFiles(FALSE)
            ->ignoreVCS(FALSE);
        return $finder;
    }
    
    /**
     * Get the root path of this Drupal codebase.
     *
     * @return string
     *   The full path to the root of this Drupal codebase.
     */
    protected function getDrupalRoot() {
        return realpath(dirname(__DIR__, 5));
    }

}