package req

import(
	"os"
	"fmt"
	"crypto/x509"
	"crypto/ecdsa"
	"crypto/rand"
	"crypto/elliptic"
	"encoding/base64"
	"encoding/pem"
	"encoding/asn1"
)
type CSRContainer struct{
	CSR					string			// Данные CSR в виде строки (PEM-блок и base64).
	PrivateKey			string			// Секретный ключ (PEM-блок и base64).
}
type subjectTemplate struct{
	Subject				subjectSet				`asn1:"set"`
}
type subjectSet struct{
	CN					subjectCN
}
type subjectCN struct{
	OID					asn1.ObjectIdentifier	
	Value				string					`asn1:"utf8"`
}
func CraftCSRandKey(name string) (CSRContainer, bool){
var res CSRContainer
var sT	subjectTemplate
	privKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to generate private key: %s\n\n", err.Error())
		return res, false
	}
	sT.Subject.CN = subjectCN{
						OID 		:	[]int{ 0x02, 0x05, 0x04, 0x03 },
						Value		:	name,
					}
	nameRaw, err := asn1.Marshal(sT)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to generate private key: %s\n\n", err.Error())
		return res, false
	}
	var csrTemplate = x509.CertificateRequest {
		RawSubject			: nameRaw,
		SignatureAlgorithm	:	x509.ECDSAWithSHA256,
	}
	csr, err := x509.CreateCertificateRequest(rand.Reader, &csrTemplate, privKey)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to generate CSR: %s\n\n", err.Error())
		return res, false
	}
	exportKey, err := x509.MarshalECPrivateKey(privKey)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to marshal private key: %s\n\n", err.Error())
		return res, false
	}
	block := &pem.Block{
		Type: "EC PRIVATE KEY",
		Bytes: exportKey,
	}
	pemEncodedKey := pem.EncodeToMemory(block)
	if pemEncodedKey == nil {
		fmt.Fprintf(os.Stderr, "Unable to generate PEM for key: %s\n\n", err.Error())
		return res, false
	}
	res.CSR = "-----BEGIN CERTIFICATE REQUEST-----" + base64.StdEncoding.EncodeToString(csr) + "-----END CERTIFICATE REQUEST-----"
	res.PrivateKey = string(pemEncodedKey)
	return res, true
}