package ldap

import (
	"strings"

	"github.com/vjeantet/goldap/message"
)

// attributeRequested reports whether an attribute selection includes
// the named attribute.
//
// Per RFC 4511 section 4.5.1.8 an empty selection, or one containing
// "*", asks for all user attributes, while "1.1" asks for none at
// all. Anything else is an explicit list. This is used to skip the
// extra NetAuth round trip needed for group membership when the client
// never asked for it.
func attributeRequested(selection message.AttributeSelection, name string) bool {
	if len(selection) == 0 {
		return true
	}
	name = strings.ToLower(name)
	for _, sel := range selection {
		switch s := strings.ToLower(strings.TrimSpace(string(sel))); {
		case s == "*":
			return true
		case s == "1.1", s == "+":
			continue
		case strings.HasPrefix(s, name+";"):
			// An attribute with options, e.g. member;binary.
			return true
		case s == name:
			return true
		}
	}
	return false
}