class ManageGitIgnore

class ManageGitIgnore {
    
    /**
     * Composer's I/O service.
     *
     * @var \Composer\IO\IOInterface
     */
    protected $io;
    
    /**
     * The directory where the project is located.
     *
     * @var string
     */
    protected $dir;
    
    /**
     * ManageGitIgnore constructor.
     *
     * @param string $dir
     *   The directory where the project is located.
     */
    public function __construct(IOInterface $io, $dir) {
        $this->io = $io;
        $this->dir = $dir;
    }
    
    /**
     * Manages gitignore files.
     *
     * @param \Drupal\Composer\Plugin\Scaffold\Operations\ScaffoldResult[] $files
     *   A list of scaffold results, each of which holds a path and whether
     *   or not that file is managed.
     * @param \Drupal\Composer\Plugin\Scaffold\ScaffoldOptions $options
     *   Configuration options from the composer.json extras section.
     */
    public function manageIgnored(array $files, ScaffoldOptions $options) {
        if (!$this->managementOfGitIgnoreEnabled($options)) {
            return;
        }
        // Accumulate entries to add to .gitignore, sorted into buckets based on the
        // location of the .gitignore file the entry should be added to.
        $add_to_git_ignore = [];
        foreach ($files as $scaffoldResult) {
            $path = $scaffoldResult->destination()
                ->fullPath();
            $is_ignored = Git::checkIgnore($this->io, $path, $this->dir);
            if (!$is_ignored) {
                $is_tracked = Git::checkTracked($this->io, $path, $this->dir);
                if (!$is_tracked && $scaffoldResult->isManaged()) {
                    $dir = realpath(dirname($path));
                    $name = basename($path);
                    $add_to_git_ignore[$dir][] = '/' . $name;
                }
            }
        }
        // Write out the .gitignore files one at a time.
        foreach ($add_to_git_ignore as $dir => $entries) {
            $this->addToGitIgnore($dir, $entries);
        }
    }
    
    /**
     * Determines whether we should manage gitignore files.
     *
     * @param \Drupal\Composer\Plugin\Scaffold\ScaffoldOptions $options
     *   Configuration options from the composer.json extras section.
     *
     * @return bool
     *   Whether or not gitignore files should be managed.
     */
    protected function managementOfGitIgnoreEnabled(ScaffoldOptions $options) {
        // If the composer.json stipulates whether gitignore is managed or not, then
        // follow its recommendation.
        if ($options->hasGitIgnore()) {
            return $options->gitIgnore();
        }
        // Do not manage .gitignore if there is no repository here.
        if (!Git::isRepository($this->io, $this->dir)) {
            return FALSE;
        }
        // If the composer.json did not specify whether or not .gitignore files
        // should be managed, then manage them if the vendor directory is ignored.
        return Git::checkIgnore($this->io, 'vendor', $this->dir);
    }
    
    /**
     * Adds a set of entries to the specified .gitignore file.
     *
     * @param string $dir
     *   Path to directory where gitignore should be written.
     * @param string[] $entries
     *   Entries to write to .gitignore file.
     */
    protected function addToGitIgnore($dir, array $entries) {
        sort($entries);
        $git_ignore_path = $dir . '/.gitignore';
        $contents = '';
        // Appending to existing .gitignore files.
        if (file_exists($git_ignore_path)) {
            $contents = file_get_contents($git_ignore_path);
            if (!empty($contents) && substr($contents, -1) != "\n") {
                $contents .= "\n";
            }
        }
        $contents .= implode("\n", $entries);
        file_put_contents($git_ignore_path, $contents);
    }

}