package atom

import (
	"errors"
	"fmt"
)

type ExtensionAttribute struct {
	Attr string `xml:",attr"`
}

// NewExtensionAttribute creates a new ExtensionAttribute. It returns a
// *ExtensionAttribute.
func NewExtensionAttribute(name, value string) *ExtensionAttribute {
	return &ExtensionAttribute{Attr: fmt.Sprint(name, `="`, value, `"`)}
}

// Check checks the ExtensionAttribute for incompatibilities with RFC4287. It
// returns an error.
func (e *ExtensionAttribute) Check() error {
	if e.Attr == "" {
		return errors.New("value element of extension attribute empty")
	}

	return nil
}