class FileBag

class FileBag extends ParameterBag {
    private const FILE_KEYS = [
        'error',
        'full_path',
        'name',
        'size',
        'tmp_name',
        'type',
    ];
    
    /**
     * @param array|UploadedFile[] $parameters An array of HTTP files
     */
    public function __construct(array $parameters = []) {
        $this->replace($parameters);
    }
    public function replace(array $files = []) : void {
        $this->parameters = [];
        $this->add($files);
    }
    public function set(string $key, mixed $value) : void {
        if (!\is_array($value) && !$value instanceof UploadedFile) {
            throw new \InvalidArgumentException('An uploaded file must be an array or an instance of UploadedFile.');
        }
        parent::set($key, $this->convertFileInformation($value));
    }
    public function add(array $files = []) : void {
        foreach ($files as $key => $file) {
            $this->set($key, $file);
        }
    }
    
    /**
     * Converts uploaded files to UploadedFile instances.
     *
     * @return UploadedFile[]|UploadedFile|null
     */
    protected function convertFileInformation(array|UploadedFile $file) : array|UploadedFile|null {
        if ($file instanceof UploadedFile) {
            return $file;
        }
        $file = $this->fixPhpFilesArray($file);
        $keys = array_keys($file + [
            'full_path' => null,
        ]);
        sort($keys);
        if (self::FILE_KEYS === $keys) {
            if (\UPLOAD_ERR_NO_FILE === $file['error']) {
                $file = null;
            }
            else {
                $file = new UploadedFile($file['tmp_name'], $file['full_path'] ?? $file['name'], $file['type'], $file['error'], false);
            }
        }
        else {
            $file = array_map(fn($v) => $v instanceof UploadedFile || \is_array($v) ? $this->convertFileInformation($v) : $v, $file);
            if (array_is_list($file)) {
                $file = array_filter($file);
            }
        }
        return $file;
    }
    
    /**
     * Fixes a malformed PHP $_FILES array.
     *
     * PHP has a bug that the format of the $_FILES array differs, depending on
     * whether the uploaded file fields had normal field names or array-like
     * field names ("normal" vs. "parent[child]").
     *
     * This method fixes the array to look like the "normal" $_FILES array.
     *
     * It's safe to pass an already converted array, in which case this method
     * just returns the original array unmodified.
     */
    protected function fixPhpFilesArray(array $data) : array {
        $keys = array_keys($data + [
            'full_path' => null,
        ]);
        sort($keys);
        if (self::FILE_KEYS !== $keys || !isset($data['name']) || !\is_array($data['name'])) {
            return $data;
        }
        $files = $data;
        foreach (self::FILE_KEYS as $k) {
            unset($files[$k]);
        }
        foreach ($data['name'] as $key => $name) {
            $files[$key] = $this->fixPhpFilesArray([
                'error' => $data['error'][$key],
                'name' => $name,
                'type' => $data['type'][$key],
                'tmp_name' => $data['tmp_name'][$key],
                'size' => $data['size'][$key],
            ] + (isset($data['full_path'][$key]) ? [
                'full_path' => $data['full_path'][$key],
            ] : []));
        }
        return $files;
    }

}