class MessageBuilderContext

class MessageBuilderContext {
    private $descriptor;
    private $pool;
    public function __construct($full_name, $klass, $pool) {
        $this->descriptor = new Descriptor();
        $this->descriptor
            ->setFullName($full_name);
        $this->descriptor
            ->setClass($klass);
        $this->pool = $pool;
    }
    private function getFieldDescriptor($name, $label, $type, $number, $type_name = null) {
        $field = new FieldDescriptor();
        $field->setName($name);
        $camel_name = implode('', array_map('ucwords', explode('_', $name)));
        $field->setGetter('get' . $camel_name);
        $field->setSetter('set' . $camel_name);
        $field->setType($type);
        $field->setNumber($number);
        $field->setLabel($label);
        // At this time, the message/enum type may have not been added to pool.
        // So we use the type name as place holder and will replace it with the
        // actual descriptor in cross building.
        switch ($type) {
            case GPBType::MESSAGE:
                $field->setMessageType($type_name);
                break;
            case GPBType::ENUM:
                $field->setEnumType($type_name);
                break;
            default:
                break;
        }
        return $field;
    }
    public function optional($name, $type, $number, $type_name = null) {
        $this->descriptor
            ->addField($this->getFieldDescriptor($name, GPBLabel::OPTIONAL, $type, $number, $type_name));
        return $this;
    }
    public function repeated($name, $type, $number, $type_name = null) {
        $this->descriptor
            ->addField($this->getFieldDescriptor($name, GPBLabel::REPEATED, $type, $number, $type_name));
        return $this;
    }
    public function required($name, $type, $number, $type_name = null) {
        $this->descriptor
            ->addField($this->getFieldDescriptor($name, GPBLabel::REQUIRED, $type, $number, $type_name));
        return $this;
    }
    public function finalizeToPool() {
        $this->pool
            ->addDescriptor($this->descriptor);
    }

}