package inspect

import (
	"crypto/rsa"
	"crypto/x509"
	"errors"
)

// DERCSRInfo attempts to parse a DER-form X.509 CSR and returns information
// about it.
func DERCSRInfo(loc string, der []byte) Info {
	csr, err := x509.ParseCertificateRequest(der)
	if err != nil {
		return &BadInfo{
			Typ:        TypeX509CSR,
			Loc:        loc,
			Underlying: err,
		}
	}

	return CSRInfo(loc, csr)
}

// CSRInfo returns information about a CSR. Note it holds a reference to the
// csr argument.
func CSRInfo(loc string, csr *x509.CertificateRequest) Info {
	key, ok := csr.PublicKey.(*rsa.PublicKey)
	if !ok {
		return &BadInfo{
			Typ:        TypeX509CSR,
			Loc:        loc,
			Underlying: errors.New("CSR public key is not RSA"),
		}
	}

	return &CSR{
		Loc:    loc,
		CSR:    csr,
		Public: PublicKeyInfo(loc, key),
	}
}

// CSR holds structured information about a CSR. It implements Info.
type CSR struct {
	// Loc is the location the CSR was encountered.
	Loc string

	// CSR is the raw CSR.
	CSR *x509.CertificateRequest

	// Public holds information about the public portion of the key.
	Public *PublicKey
}

// Type indicates this is a private key.
func (csr *CSR) Type() Type {
	return TypeX509CSR
}

// Location returns the location data stored by PrivateKeyInfo.
func (csr *CSR) Location() string {
	return csr.Loc
}

// Info returns structured information about the prvate key.
func (csr *CSR) Info() []Section {
	return []Section{
		csr.SubjectSection(),
		csr.Public.PublicKeyInfoSection(),
	}
}

// SubjectSection returns information about the subject.
func (csr *CSR) SubjectSection() Section {
	f := []Field{
		Field{
			Key:   "Description",
			Value: csr.CSR.Subject.CommonName,
		},
	}
	f = appendX509DNField(f, csr.CSR.Subject)
	if len(csr.CSR.DNSNames) > 0 {
		f = append(f, Field{
			Key:   "Hostnames",
			Value: csr.CSR.DNSNames,
		})
	}
	if len(csr.CSR.IPAddresses) > 0 {
		var ips []string
		for _, ip := range csr.CSR.IPAddresses {
			ips = append(ips, ip.String())
		}
		f = append(f, Field{
			Key:   "IP addresses",
			Value: ips,
		})
	}

	return Section{
		Title:  "Subject",
		Fields: f,
	}
}