class GenerateTheme

class GenerateTheme extends Command {
    
    /**
     * The path for the Drupal root.
     *
     * @var string
     */
    private $root;
    
    /**
     * GenerateTheme constructor.
     *
     * @param string|null $name
     *   The name of the command; passing null means it must be set in configure().
     * @param string|null $root
     *   The path for the Drupal root.
     */
    public function __construct(?string $name = NULL, ?string $root = NULL) {
        parent::__construct($name);
        $this->root = $root ?? dirname(__DIR__, 5);
    }
    
    /**
     * {@inheritdoc}
     */
    protected function configure() : void {
        $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', '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');
    }
    protected function initialize(InputInterface $input, OutputInterface $output) : void {
        if ($input->getOption('name') === NULL) {
            $input->setOption('name', $input->getArgument('machine-name'));
        }
        // Change the directory to the Drupal root.
        chdir($this->root);
    }
    
    /**
     * {@inheritdoc}
     */
    protected function execute(InputInterface $input, OutputInterface $output) : int {
        $io = new SymfonyStyle($input, $output);
        $filesystem = new Filesystem();
        $tmpDir = $this->getUniqueTmpDirPath();
        $destination_theme = $input->getArgument('machine-name');
        $starterkit_id = $input->getOption('starterkit');
        $theme_label = $input->getOption('name');
        $io->writeln("<info>Generating theme {$theme_label} ({$destination_theme}) from {$starterkit_id} starterkit.</info>");
        $destination = trim($input->getOption('path'), '/') . '/' . $destination_theme;
        if (is_dir($destination)) {
            $io->getErrorStyle()
                ->error("Theme could not be generated because the destination directory {$destination} exists already.");
            return 1;
        }
        $starterkit = $this->getThemeInfo($starterkit_id);
        if ($starterkit === NULL) {
            $io->getErrorStyle()
                ->error("Theme source theme {$starterkit_id} cannot be found.");
            return 1;
        }
        $io->writeln("Trying to parse version for {$starterkit_id} starterkit.", OutputInterface::VERBOSITY_DEBUG);
        try {
            $starterkit_version = self::getStarterKitVersion($starterkit, $io);
        } catch (\Exception $e) {
            $io->getErrorStyle()
                ->error($e->getMessage());
            return 1;
        }
        $io->writeln("Using version {$starterkit_version} for {$starterkit_id} starterkit.", OutputInterface::VERBOSITY_DEBUG);
        $io->writeln("Loading starterkit config from {$starterkit_id}.starterkit.yml.", OutputInterface::VERBOSITY_DEBUG);
        try {
            $starterkit_config = self::loadStarterKitConfig($starterkit, $starterkit_version, $theme_label, $input->getOption('description'));
        } catch (\Exception $e) {
            $io->getErrorStyle()
                ->error($e->getMessage());
            return 1;
        }
        $filesystem->mkdir($tmpDir);
        $io->writeln("Copying starterkit to temporary directory for processing.", OutputInterface::VERBOSITY_DEBUG);
        $mirror_iterator = (new Finder())->in($starterkit->getPath())
            ->files()
            ->ignoreDotFiles(FALSE)
            ->notName($starterkit_config['ignore'])
            ->notPath($starterkit_config['ignore']);
        $filesystem->mirror($starterkit->getPath(), $tmpDir, $mirror_iterator);
        $io->writeln("Modifying and renaming files from starterkit.", OutputInterface::VERBOSITY_DEBUG);
        $patterns = [
            'old' => self::namePatterns($starterkit->getName(), $starterkit->info['name']),
            'new' => self::namePatterns($destination_theme, $theme_label),
        ];
        $filesToEdit = self::createFilesFinder($tmpDir)->contains(array_values($patterns['old']))
            ->notPath($starterkit_config['no_edit']);
        foreach ($filesToEdit as $file) {
            $contents = file_get_contents($file->getRealPath());
            $contents = str_replace($patterns['old'], $patterns['new'], $contents);
            file_put_contents($file->getRealPath(), $contents);
        }
        $filesToRename = self::createFilesFinder($tmpDir)->name(array_map(static fn(string $pattern) => "*{$pattern}*", array_values($patterns['old'])))
            ->notPath($starterkit_config['no_rename']);
        foreach ($filesToRename as $file) {
            $filepath_segments = explode('/', $file->getRealPath());
            $filename = array_pop($filepath_segments);
            $filename = str_replace($patterns['old'], $patterns['new'], $filename);
            $filepath_segments[] = $filename;
            $filesystem->rename($file->getRealPath(), implode('/', $filepath_segments));
        }
        $io->writeln("Updating {$destination_theme}.info.yml.", OutputInterface::VERBOSITY_DEBUG);
        $info_file = "{$tmpDir}/{$destination_theme}.info.yml";
        $info = Yaml::decode(file_get_contents($info_file));
        $info = array_filter(array_merge($info, $starterkit_config['info']), static fn(mixed $value) => $value !== NULL);
        // Ensure the generated theme is not hidden.
        unset($info['hidden']);
        file_put_contents($info_file, Yaml::encode($info));
        $loader = new ClassLoader();
        $loader->addPsr4("Drupal\\{$starterkit->getName()}\\", "{$starterkit->getPath()}/src");
        $loader->register();
        $generator_classname = "Drupal\\{$starterkit->getName()}\\StarterKit";
        if (class_exists($generator_classname)) {
            if (is_a($generator_classname, StarterKitInterface::class, TRUE)) {
                $io->writeln("Running post processing.", OutputInterface::VERBOSITY_DEBUG);
                $generator_classname::postProcess($tmpDir, $destination_theme, $theme_label);
            }
            else {
                $io->getErrorStyle()
                    ->error("The {$generator_classname} does not implement \\Drupal\\Core\\Theme\\StarterKitInterface and cannot perform post-processing.");
                return 1;
            }
        }
        else {
            $io->writeln("Skipping post processing, {$generator_classname} not defined.", OutputInterface::VERBOSITY_DEBUG);
        }
        // Move altered theme to final destination.
        $io->writeln("Copying {$destination_theme} to {$destination}.", OutputInterface::VERBOSITY_DEBUG);
        $filesystem->mirror($tmpDir, $destination);
        $io->writeln(sprintf('Theme generated successfully to %s', $destination));
        return 0;
    }
    
    /**
     * 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_name
     *   The machine name of the theme.
     *
     * @return \Drupal\Core\Extension\Extension|null
     */
    private function getThemeInfo(string $theme_name) : ?Extension {
        $extension_discovery = new ExtensionDiscovery($this->root, FALSE, []);
        $themes = $extension_discovery->scan('theme');
        $theme = $themes[$theme_name] ?? NULL;
        if ($theme !== NULL) {
            $theme->info = (new InfoParser($this->root))
                ->parse($theme->getPathname());
        }
        return $theme;
    }
    private static function createFilesFinder(string $dir) : Finder {
        return (new Finder())->in($dir)
            ->files();
    }
    private static function loadStarterKitConfig(Extension $theme, string $version, string $name, string $description) : array {
        $starterkit_config_file = $theme->getPath() . '/' . $theme->getName() . '.starterkit.yml';
        if (!file_exists($starterkit_config_file)) {
            throw new \RuntimeException("Theme source theme {$theme->getName()} is not a valid starter kit.");
        }
        $starterkit_config_defaults = [
            'info' => [
                'name' => $name,
                'description' => $description,
                'core_version_requirement' => '^' . explode('.', \Drupal::VERSION)[0],
                'version' => '1.0.0',
                'generator' => "{$theme->getName()}:{$version}",
            ],
            'ignore' => [
                '/src/StarterKit.php',
                '/*.starterkit.yml',
            ],
            'no_edit' => [],
            'no_rename' => [],
        ];
        $starterkit_config = Yaml::decode(file_get_contents($starterkit_config_file));
        if (!is_array($starterkit_config)) {
            throw new \RuntimeException('Starterkit config is was not able to be parsed.');
        }
        if (!isset($starterkit_config['info'])) {
            $starterkit_config['info'] = [];
        }
        $starterkit_config['info'] = array_merge($starterkit_config_defaults['info'], $starterkit_config['info']);
        foreach ([
            'ignore',
            'no_edit',
            'no_rename',
        ] as $key) {
            if (!isset($starterkit_config[$key])) {
                $starterkit_config[$key] = $starterkit_config_defaults[$key];
            }
            if (!is_array($starterkit_config[$key])) {
                throw new \RuntimeException("{$key} in starterkit.yml must be an array");
            }
            $starterkit_config[$key] = array_map(static fn(string $path) => Glob::toRegex(trim($path, '/')), $starterkit_config[$key]);
            if (count($starterkit_config[$key]) > 0) {
                $files = self::createFilesFinder($theme->getPath())
                    ->path($starterkit_config[$key]);
                $starterkit_config[$key] = array_map(static fn($file) => $file->getRelativePathname(), iterator_to_array($files));
                if (count($starterkit_config[$key]) === 0) {
                    throw new \RuntimeException("Paths were defined `{$key}` but no files found.");
                }
            }
        }
        return $starterkit_config;
    }
    private static function getStarterKitVersion(Extension $theme, SymfonyStyle $io) : string {
        $source_version = $theme->info['version'] ?? '';
        if ($source_version === '') {
            $confirm = 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?', $theme->getName()));
            if (!$io->askQuestion($confirm)) {
                throw new \RuntimeException('source version could not be determined');
            }
            $source_version = 'unknown-version';
        }
        if ($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()) {
                throw new \RuntimeException(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.', $theme->getName(), $source_version));
            }
            // Get the git commit for the source theme.
            $git_get_commit = Process::fromShellCommandline("git rev-list --max-count=1 --abbrev-commit HEAD -C {$theme->getPath()}");
            $git_get_commit->run();
            if (!$git_get_commit->isSuccessful() || $git_get_commit->getOutput() === '') {
                $confirm = 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?', $theme->getName(), $source_version));
                if (!$io->askQuestion($confirm)) {
                    throw new \RuntimeException('source version could not be determined');
                }
                $source_version .= '#unknown-commit';
            }
            else {
                $source_version .= '#' . trim($git_get_commit->getOutput());
            }
        }
        return $source_version;
    }
    private static function namePatterns(string $machine_name, string $label) : array {
        return [
            'machine_name' => $machine_name,
            'machine_name_camel' => u($machine_name)->camel(),
            'machine_name_pascal' => u($machine_name)->camel()
                ->title(),
            'machine_name_title' => u($machine_name)->title(),
            'label' => $label,
            'label_camel' => u($label)->camel(),
            'label_pascal' => u($label)->camel()
                ->title(),
            'label_title' => u($label)->title(),
        ];
    }

}