class GenerateTheme

class GenerateTheme extends Command {
    
    /**
     * The path for the Drupal root.
     *
     * @var string
     */
    private $root;
    
    /**
     * {@inheritdoc}
     */
    public function __construct(string $name = NULL) {
        parent::__construct($name);
        $this->root = dirname(__DIR__, 5);
    }
    
    /**
     * {@inheritdoc}
     */
    protected function configure() {
        $this->setName('generate-theme')
            ->setDescription('Generates a new theme based on latest default markup.')
            ->addArgument('machine-name', InputArgument::REQUIRED, 'The machine name of the generated theme')
            ->addOption('name', NULL, InputOption::VALUE_OPTIONAL, 'A name for the theme.')
            ->addOption('description', NULL, InputOption::VALUE_OPTIONAL, 'A description of your theme.')
            ->addOption('path', NULL, InputOption::VALUE_OPTIONAL, 'The path where your theme will be created. Defaults to: themes')
            ->addOption('starterkit', NULL, InputOption::VALUE_OPTIONAL, 'The theme to use as the starterkit', 'starterkit_theme')
            ->addUsage('custom_theme --name "Custom Theme" --description "Custom theme generated from a starterkit theme" --path themes')
            ->addUsage('custom_theme --name "Custom Theme" --starterkit mystarterkit');
    }
    
    /**
     * {@inheritdoc}
     */
    protected function execute(InputInterface $input, OutputInterface $output) {
        $io = new SymfonyStyle($input, $output);
        // Change the directory to the Drupal root.
        chdir($this->root);
        // Path where the generated theme should be placed.
        $destination_theme = $input->getArgument('machine-name');
        $default_destination = 'themes';
        $destination = trim($input->getOption('path') ?: $default_destination, '/') . '/' . $destination_theme;
        if (is_dir($destination)) {
            $io->getErrorStyle()
                ->error("Theme could not be generated because the destination directory {$destination} exists already.");
            return 1;
        }
        // Source directory for the theme.
        $source_theme_name = $input->getOption('starterkit');
        if (!($source_theme = $this->getThemeInfo($source_theme_name))) {
            $io->getErrorStyle()
                ->error("Theme source theme {$source_theme_name} cannot be found.");
            return 1;
        }
        if (!$this->isStarterkitTheme($source_theme)) {
            $io->getErrorStyle()
                ->error("Theme source theme {$source_theme_name} is not a valid starter kit.");
            return 1;
        }
        $source = $source_theme->getPath();
        if (!is_dir($source)) {
            $io->getErrorStyle()
                ->error("Theme could not be generated because the source directory {$source} does not exist.");
            return 1;
        }
        $tmp_dir = $this->getUniqueTmpDirPath();
        $this->copyRecursive($source, $tmp_dir);
        // Readme is specific to Starterkit, so remove it from the generated theme.
        $readme_file = "{$tmp_dir}/README.md";
        if (!file_put_contents($readme_file, "{$destination_theme} theme, generated from {$source_theme_name}. Additional information on generating themes can be found in the [Starterkit documentation](https://www.drupal.org/docs/core-modules-and-themes/core-themes/starterkit-theme).")) {
            $io->getErrorStyle()
                ->error("The readme could not be rewritten.");
            return 1;
        }
        // Rename files based on the theme machine name.
        $file_pattern = "/{$source_theme_name}\\.(theme|[^.]+\\.yml)/";
        if ($files = @scandir($tmp_dir)) {
            foreach ($files as $file) {
                $location = $tmp_dir . '/' . $file;
                if (is_dir($location)) {
                    continue;
                }
                if (preg_match($file_pattern, $file, $matches)) {
                    if (!rename($location, $tmp_dir . '/' . $destination_theme . '.' . $matches[1])) {
                        $io->getErrorStyle()
                            ->error("The file {$location} could not be moved.");
                        return 1;
                    }
                }
            }
        }
        else {
            $io->getErrorStyle()
                ->error("Temporary directory {$tmp_dir} cannot be opened.");
            return 1;
        }
        // Info file.
        $info_file = "{$tmp_dir}/{$destination_theme}.info.yml";
        if (!file_exists($info_file)) {
            $io->getErrorStyle()
                ->error("The theme info file {$info_file} could not be read.");
            return 1;
        }
        $info = Yaml::decode(file_get_contents($info_file));
        $info['name'] = $input->getOption('name') ?: $destination_theme;
        $info['core_version_requirement'] = '^' . $this->getVersion();
        if (!array_key_exists('version', $info)) {
            $confirm_versionless_source_theme = new ConfirmationQuestion(sprintf('The source theme %s does not have a version specified. This makes tracking changes in the source theme difficult. Are you sure you want to continue?', $source_theme->getName()));
            if (!$io->askQuestion($confirm_versionless_source_theme)) {
                return 0;
            }
        }
        $source_version = $info['version'] ?? 'unknown-version';
        if ($source_version === 'VERSION') {
            $source_version = \Drupal::VERSION;
        }
        // A version in the generator string like "9.4.0-dev" is not very helpful.
        // When this occurs, generate a version string that points to a commit.
        if (VersionParser::parseStability($source_version) === 'dev') {
            $git_check = Process::fromShellCommandline('git --help');
            $git_check->run();
            if ($git_check->getExitCode()) {
                $io->error(sprintf('The source theme %s has a development version number (%s). Determining a specific commit is not possible because git is not installed. Either install git or use a tagged release to generate a theme.', $source_theme->getName(), $source_version));
                return 1;
            }
            // Get the git commit for the source theme.
            $git_get_commit = Process::fromShellCommandline("git rev-list --max-count=1 --abbrev-commit HEAD -C {$source}");
            $git_get_commit->run();
            if ($git_get_commit->getOutput() === '') {
                $confirm_packaged_dev_release = new ConfirmationQuestion(sprintf('The source theme %s has a development version number (%s). Because it is not a git checkout, a specific commit could not be identified. This makes tracking changes in the source theme difficult. Are you sure you want to continue?', $source_theme->getName(), $source_version));
                if (!$io->askQuestion($confirm_packaged_dev_release)) {
                    return 0;
                }
                $source_version .= '#unknown-commit';
            }
            else {
                $source_version .= '#' . trim($git_get_commit->getOutput());
            }
        }
        $info['generator'] = "{$source_theme_name}:{$source_version}";
        if ($description = $input->getOption('description')) {
            $info['description'] = $description;
        }
        else {
            unset($info['description']);
        }
        // Replace references to libraries.
        if (isset($info['libraries'])) {
            $info['libraries'] = preg_replace("/{$source_theme_name}(\\/.*)/", "{$destination_theme}\$1", $info['libraries']);
        }
        if (isset($info['libraries-extend'])) {
            foreach ($info['libraries-extend'] as $key => $value) {
                $info['libraries-extend'][$key] = preg_replace("/{$source_theme_name}(\\/.*)/", "{$destination_theme}\$1", $info['libraries-extend'][$key]);
            }
        }
        if (isset($info['libraries-override'])) {
            foreach ($info['libraries-override'] as $key => $value) {
                if (isset($info['libraries-override'][$key]['dependencies'])) {
                    $info['libraries-override'][$key]['dependencies'] = preg_replace("/{$source_theme_name}(\\/.*)/", "{$destination_theme}\$1", $info['libraries-override'][$key]['dependencies']);
                }
            }
        }
        if (!file_put_contents($info_file, Yaml::encode($info))) {
            $io->getErrorStyle()
                ->error("The theme info file {$info_file} could not be written.");
            return 1;
        }
        // Replace references to libraries in libraries.yml file.
        $libraries_file = "{$tmp_dir}/{$destination_theme}.libraries.yml";
        if (file_exists($libraries_file)) {
            $libraries = Yaml::decode(file_get_contents($libraries_file));
            foreach ($libraries as $key => $value) {
                if (isset($libraries[$key]['dependencies'])) {
                    $libraries[$key]['dependencies'] = preg_replace("/{$source_theme_name}(\\/.*)/", "{$destination_theme}\$1", $libraries[$key]['dependencies']);
                }
            }
            if (!file_put_contents($libraries_file, Yaml::encode($libraries))) {
                $io->getErrorStyle()
                    ->error("The libraries file {$libraries_file} could not be written.");
                return 1;
            }
        }
        // Rename hooks.
        $theme_file = "{$tmp_dir}/{$destination_theme}.theme";
        if (file_exists($theme_file)) {
            if (!file_put_contents($theme_file, preg_replace("/(function )({$source_theme_name})(_.*)/", "\$1{$destination_theme}\$3", file_get_contents($theme_file)))) {
                $io->getErrorStyle()
                    ->error("The theme file {$theme_file} could not be written.");
                return 1;
            }
        }
        // Rename references to libraries in templates.
        $iterator = new TemplateDirIterator(new \RegexIterator(new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($tmp_dir), \RecursiveIteratorIterator::LEAVES_ONLY), '/' . preg_quote('.html.twig') . '$/'));
        foreach ($iterator as $template_file => $contents) {
            $new_template_content = preg_replace("/(attach_library\\(['\")]){$source_theme_name}(\\/.*['\"]\\))/", "\$1{$destination_theme}\$2", $contents);
            if (!file_put_contents($template_file, $new_template_content)) {
                $io->getErrorStyle()
                    ->error("The template file {$template_file} could not be written.");
                return 1;
            }
        }
        $loader = new ClassLoader();
        $loader->addPsr4("Drupal\\{$source_theme_name}\\", "{$source}/src");
        $loader->register();
        $generator_classname = "Drupal\\{$source_theme_name}\\StarterKit";
        if (class_exists($generator_classname)) {
            if (is_a($generator_classname, StarterKitInterface::class, TRUE)) {
                $generator_classname::postProcess($tmp_dir, $destination_theme, $info['name']);
            }
            else {
                $io->getErrorStyle()
                    ->error("The {$generator_classname} does not implement \\Drupal\\Core\\Theme\\StarterKitInterface and cannot perform post-processing.");
                return 1;
            }
        }
        if (!@rename($tmp_dir, $destination)) {
            // If rename fails, copy the files to the destination directory. This is
            // expected to happen when the tmp directory is on a different file
            // system.
            $this->copyRecursive($tmp_dir, $destination);
            // Renaming would not have left anything behind. Ensure that is still the
            // case.
            $this->rmRecursive($tmp_dir);
        }
        $output->writeln(sprintf('Theme generated successfully to %s', $destination));
        return 0;
    }
    
    /**
     * Removes a directory recursively.
     *
     * @param string $dir
     *   A directory to be removed.
     */
    private function rmRecursive(string $dir) : void {
        $files = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($dir, \RecursiveDirectoryIterator::SKIP_DOTS), \RecursiveIteratorIterator::CHILD_FIRST);
        foreach ($files as $file) {
            is_dir($file) ? rmdir($file) : unlink($file);
        }
    }
    
    /**
     * Copies files recursively.
     *
     * @param string $src
     *   A file or directory to be copied.
     * @param string $dest
     *   Destination directory where the directory or file should be copied.
     *
     * @throws \RuntimeException
     *   Exception thrown if copying failed.
     */
    private function copyRecursive($src, $dest) : void {
        // Copy all subdirectories and files.
        if (is_dir($src)) {
            if (!mkdir($dest, FileSystem::CHMOD_DIRECTORY, FALSE)) {
                throw new \RuntimeException("Directory {$dest} could not be created");
            }
            $handle = opendir($src);
            while ($file = readdir($handle)) {
                if ($file != "." && $file != "..") {
                    $this->copyRecursive("{$src}/{$file}", "{$dest}/{$file}");
                }
            }
            closedir($handle);
        }
        elseif (is_link($src)) {
            symlink(readlink($src), $dest);
        }
        elseif (!copy($src, $dest)) {
            throw new \RuntimeException("File {$src} could not be copied to {$dest}");
        }
        // Set permissions for the directory or file.
        if (!is_link($dest)) {
            if (is_dir($dest)) {
                $mode = FileSystem::CHMOD_DIRECTORY;
            }
            else {
                $mode = FileSystem::CHMOD_FILE;
            }
            if (!chmod($dest, $mode)) {
                throw new \RuntimeException("The file permissions could not be set on {$src}");
            }
        }
    }
    
    /**
     * Generates a path to a temporary location.
     *
     * @return string
     */
    private function getUniqueTmpDirPath() : string {
        return sys_get_temp_dir() . '/drupal-starterkit-theme-' . uniqid(md5(microtime()), TRUE);
    }
    
    /**
     * Gets theme info using the theme name.
     *
     * @param string $theme
     *   The machine name of the theme.
     *
     * @return \Drupal\Core\Extension\Extension|null
     */
    private function getThemeInfo(string $theme) : ?Extension {
        $extension_discovery = new ExtensionDiscovery($this->root, FALSE, []);
        $themes = $extension_discovery->scan('theme');
        if (!isset($themes[$theme])) {
            return NULL;
        }
        return $themes[$theme];
    }
    
    /**
     * Checks if the theme is a starterkit theme.
     *
     * @param \Drupal\Core\Extension\Extension $theme
     *   The theme extension.
     *
     * @return bool
     */
    private function isStarterkitTheme(Extension $theme) : bool {
        $info_parser = new InfoParser($this->root);
        $info = $info_parser->parse($theme->getPathname());
        return $info['starterkit'] ?? FALSE === TRUE;
    }
    
    /**
     * Gets the current Drupal major version.
     *
     * @return string
     */
    private function getVersion() : string {
        return explode('.', \Drupal::VERSION)[0];
    }

}