// limitations under the License.

package util

import (
	"fmt"
	"strings"
)

// DualUseCommonName extracts a valid CommonName from a comma-delimited host string
// for dual-use certificates.
func DualUseCommonName(host string) (string, error) {
	// cn uses one hostname, drop the rest
	first := strings.SplitN(host, ",", 2)[0]

			expectedCN: "a.com",
		},
		{
			name:      "long host",
			host:      strings.Repeat("a", 61) + ".com",
			expectErr: true,
		},
	}

	for _, tc := range tt {
		cn, err := DualUseCommonName(tc.host)
		if tc.expectErr {
			if err == nil {
				t.Errorf("[%s] passed - expected error", tc.name)
			}
			continue
		}

		if err != nil {
			t.Errorf("[%s] unexpected error: %v", tc.name, err)
		}

	}
	exts := []pkix.Extension{*ext}

	subject := pkix.Name{}
	// Dual use mode if common name in CSR is not empty.
	// In this case, set CN as determined by DualUseCommonName(subjectIDsInString).
	if len(csr.Subject.CommonName) != 0 {
		if cn, err := DualUseCommonName(subjectIDsInString); err != nil {
			// log and continue
			log.Errorf("dual-use failed for cert template - omitting CN (%v)", err)
		} else {

		},
	}

	if h := options.Host; len(h) > 0 {
		s, err := BuildSubjectAltNameExtension(h)
		if err != nil {
			return nil, err
		}
		if options.IsDualUse {
			cn, err := DualUseCommonName(h)
			if err != nil {
				// log and continue
				log.Errorf("dual-use failed for CSR template - omitting CN (%v)", err)
			} else {
				template.Subject.CommonName = cn
			}
		}