package atom

import (
	"encoding/xml"
	"errors"
)

type ExtensionElement struct {
	Value   any `xml:",innerxml"`
	XMLName xml.Name
}

// NewExtensionElement creates a new ExtensionElement. It returns a
// *ExtensionElement and an error.
func NewExtensionElement(name string, value any) (*ExtensionElement, error) {
	if name == "" {
		return nil, errors.New("error adding extension attribute: name string empty")
	}
	if value == "" {
		return nil, errors.New("error adding extension attribute: value string empty")
	}

	return &ExtensionElement{XMLName: xml.Name{Local: name}, Value: value}, nil
}

// Check checks the ExtensionElement for incompatibilities with RFC4287. It
// returns an error.
func (e *ExtensionElement) Check() error {
	if e.XMLName.Local == "" {
		return errors.New("xml name of extension empty")
	}

	if e.Value == nil {
		return errors.New("value element of extension empty")
	}

	return nil
}