package e2e

import (
	"crypto/rand"
	"io"
	"net/netip"
	"time"

	"github.com/slackhq/nebula/cert"
	"golang.org/x/crypto/curve25519"
	"golang.org/x/crypto/ed25519"
)

// NewTestCaCert will generate a CA cert
func NewTestCaCert(before, after time.Time, networks, unsafeNetworks []netip.Prefix, groups []string) (cert.Certificate, []byte, []byte, []byte) {
	pub, priv, err := ed25519.GenerateKey(rand.Reader)
	if before.IsZero() {
		before = time.Now().Add(time.Second * -60).Round(time.Second)
	}
	if after.IsZero() {
		after = time.Now().Add(time.Second * 60).Round(time.Second)
	}

	t := &cert.TBSCertificate{
		Version:        cert.Version1,
		Name:           "test ca",
		NotBefore:      time.Unix(before.Unix(), 0),
		NotAfter:       time.Unix(after.Unix(), 0),
		PublicKey:      pub,
		Networks:       networks,
		UnsafeNetworks: unsafeNetworks,
		Groups:         groups,
		IsCA:           true,
	}

	c, err := t.Sign(nil, cert.Curve_CURVE25519, priv)
	if err != nil {
		panic(err)
	}

	pem, err := c.MarshalPEM()
	if err != nil {
		panic(err)
	}

	return c, pub, priv, pem
}

// NewTestCert will generate a signed certificate with the provided details.
// Expiry times are defaulted if you do not pass them in
func NewTestCert(v cert.Version, ca cert.Certificate, key []byte, name string, before, after time.Time, networks, unsafeNetworks []netip.Prefix, groups []string) (cert.Certificate, []byte, []byte, []byte) {
	if before.IsZero() {
		before = time.Now().Add(time.Second * -60).Round(time.Second)
	}

	if after.IsZero() {
		after = time.Now().Add(time.Second * 60).Round(time.Second)
	}

	pub, rawPriv := x25519Keypair()
	nc := &cert.TBSCertificate{
		Version:        v,
		Name:           name,
		Networks:       networks,
		UnsafeNetworks: unsafeNetworks,
		Groups:         groups,
		NotBefore:      time.Unix(before.Unix(), 0),
		NotAfter:       time.Unix(after.Unix(), 0),
		PublicKey:      pub,
		IsCA:           false,
	}

	c, err := nc.Sign(ca, ca.Curve(), key)
	if err != nil {
		panic(err)
	}

	pem, err := c.MarshalPEM()
	if err != nil {
		panic(err)
	}

	return c, pub, cert.MarshalPrivateKeyToPEM(cert.Curve_CURVE25519, rawPriv), pem
}

func x25519Keypair() ([]byte, []byte) {
	privkey := make([]byte, 32)
	if _, err := io.ReadFull(rand.Reader, privkey); err != nil {
		panic(err)
	}

	pubkey, err := curve25519.X25519(privkey, curve25519.Basepoint)
	if err != nil {
		panic(err)
	}

	return pubkey, privkey
}