// Encrypt plainText into an Encrypted Message using the given public key.
func Encrypt(log chan string, dest_pubkey []byte, plainText string) *EncryptedMessage {
	// Generate New Public/Private Key Pair
	D1, X1, Y1 := CreateKey(log)
	// Unmarshal the Destination's Pubkey
	X2, Y2 := elliptic.Unmarshal(elliptic.P256(), dest_pubkey)

	// Point Multiply to get new Pubkey
	PubX, PubY := elliptic.P256().ScalarMult(X2, Y2, D1)

	// Generate Pubkey hashes
	PubHash := sha512.Sum512(elliptic.Marshal(elliptic.P256(), PubX, PubY))
	PubHash_E := PubHash[:32]
	PubHash_M := PubHash[32:64]

	IV, cipherText, _ := SymmetricEncrypt(PubHash_E, plainText)

	// Generate HMAC
	mac := hmac.New(sha256.New, PubHash_M)
	mac.Write(cipherText)
	HMAC := mac.Sum(nil)

	ret := new(EncryptedMessage)
	copy(ret.IV[:], IV[:])
	copy(ret.PublicKey[:], elliptic.Marshal(elliptic.P256(), X1, Y1))
	ret.CipherText = cipherText
	copy(ret.HMAC[:], HMAC)

	return ret
}

// Tests whether a message can be signed, and wrapped in plain-text.
func TestMessageCleartextSignRecover(t *testing.T) {
	key, err := crypto.GenerateKey()
	if err != nil {
		t.Fatalf("failed to create crypto key: %v", err)
	}
	payload := []byte("hello world")

	msg := NewMessage(payload)
	if _, err := msg.Wrap(DefaultPoW, Options{
		From: key,
	}); err != nil {
		t.Fatalf("failed to sign message: %v", err)
	}
	if msg.Flags&signatureFlag != signatureFlag {
		t.Fatalf("signature flag mismatch: have %d, want %d", msg.Flags&signatureFlag, signatureFlag)
	}
	if bytes.Compare(msg.Payload, payload) != 0 {
		t.Fatalf("payload mismatch after signing: have 0x%x, want 0x%x", msg.Payload, payload)
	}

	pubKey := msg.Recover()
	if pubKey == nil {
		t.Fatalf("failed to recover public key")
	}
	p1 := elliptic.Marshal(crypto.S256(), key.PublicKey.X, key.PublicKey.Y)
	p2 := elliptic.Marshal(crypto.S256(), pubKey.X, pubKey.Y)
	if !bytes.Equal(p1, p2) {
		t.Fatalf("public key mismatch: have 0x%x, want 0x%x", p2, p1)
	}
}

func MarshalMark(c elliptic.Curve, m *Mark) []byte {
	bytelen := (c.Params().BitSize + 7) >> 3
	pointlen := 1 + 2*bytelen
	outlen := 2 * pointlen
	ret := make([]byte, outlen, outlen)
	abytes := elliptic.Marshal(c, m.ax, m.ay)
	copy(ret, abytes)
	bbytes := elliptic.Marshal(c, m.bx, m.by)
	copy(ret[pointlen:], bbytes)
	return ret
}

// GenerateKeypair generates a public and private ECDSA key, for
// later user with NewIssuer or NewVerifier. These are written
// as binary files, because PEM is pointless.
func GenerateKeypair(filename string) (err error) {
	priv, err := ecdsa.GenerateKey(curveEll, rand.Reader)
	if err != nil {
		return
	}
	err = ioutil.WriteFile(filename+".priv", elliptic.Marshal(curveEll, priv.x, priv.y), FileMode(0600))
	if err != nil {
		return
	}
	err = ioutil.WriteFile(filename+".pub", elliptic.Marshal(curveEll, pub.x, pub.y), FileMode(0644))
	return
	// TODO(dlg): also write out JWK
}

// cmpPublic returns true if the two public keys represent the same pojnt.
func cmpPublic(pub1, pub2 PublicKey) bool {
	if pub1.X == nil || pub1.Y == nil {
		fmt.Println(ErrInvalidPublicKey.Error())
		return false
	}
	if pub2.X == nil || pub2.Y == nil {
		fmt.Println(ErrInvalidPublicKey.Error())
		return false
	}
	pub1Out := elliptic.Marshal(pub1.Curve, pub1.X, pub1.Y)
	pub2Out := elliptic.Marshal(pub2.Curve, pub2.X, pub2.Y)

	return bytes.Equal(pub1Out, pub2Out)
}

func FillBallot(c elliptic.Curve, px *big.Int, py *big.Int, entry int,
	size int) *Ballot {
	b := new(Ballot)
	b.boxes = make([]*Checkbox, size, size)
	for i := 0; i < size; i++ {
		if i == entry {
			b.boxes[i] = VoteOne(c, px, py)
		} else {
			b.boxes[i] = VoteZero(c, px, py)
		}
	}
	//TODO: add validation
	//Let A be the sum of all the A, B the sum of all the B
	//Then we want log_g(A)=log_h(B-g)

	ax := big.NewInt(0)
	ay := big.NewInt(0)
	bx := big.NewInt(0)
	by := big.NewInt(0)
	s := big.NewInt(0)
	for i := 0; i < size; i++ {
		ax, ay = c.Add(ax, ay, b.boxes[i].ax, b.boxes[i].ay)
		bx, by = c.Add(bx, by, b.boxes[i].bx, b.boxes[i].by)
		s.Add(s, b.boxes[i].s)
	}
	s.Mod(s, c.Params().N)
	k, err := rand.Int(rand.Reader, c.Params().N)
	if err != nil {
		panic("Not here, not now")
	}
	v1x, v1y := c.ScalarBaseMult(k.Bytes())
	v2x, v2y := c.ScalarMult(px, py, k.Bytes())
	var commit [4][]byte
	commit[0] = elliptic.Marshal(c, ax, ay)
	commit[1] = elliptic.Marshal(c, bx, by)
	commit[2] = elliptic.Marshal(c, v1x, v1y)
	commit[3] = elliptic.Marshal(c, v2x, v2y)
	cb := bytes.Join(commit[:], []byte{})
	cbytes := sha256.Sum256(cb[:])
	b.c = big.NewInt(0)
	b.c.SetBytes(cbytes[:])
	b.c.Mod(b.c, c.Params().N)
	b.r = big.NewInt(0)
	//r=k-c*s
	b.r.Mul(b.c, s)
	b.r.Sub(k, b.r)
	b.r.Mod(b.r, c.Params().N)
	return b
}

// marshalECDSASHASigningKeyV1 encodes a private key as a protobuf message.
func marshalECDSASHASigningKeyV1(k *ecdsa.PrivateKey) *ECDSA_SHA_SigningKeyV1 {
	return &ECDSA_SHA_SigningKeyV1{
		Curve:     NamedEllipticCurve_PRIME256_V1.Enum(),
		EcPrivate: k.D.Bytes(),
		EcPublic:  elliptic.Marshal(k.Curve, k.X, k.Y),
	}
}

func marshalECDSAKey(priv *ecdsa.PrivateKey) (out []byte, err error) {
	var eckey ecPrivateKey

	eckey.Version = 1
	eckey.PrivateKey = priv.D.Bytes()
	switch priv.PublicKey.Curve {
	case elliptic.P256():
		eckey.NamedCurveOID = oidNamedCurveP256
	case elliptic.P384():
		eckey.NamedCurveOID = oidNamedCurveP384
	case elliptic.P521():
		eckey.NamedCurveOID = oidNamedCurveP521
	default:
		err = ErrInvalidPrivateKey
	}

	pkey := elliptic.Marshal(priv.PublicKey.Curve, priv.PublicKey.X,
		priv.PublicKey.Y)
	if pkey == nil {
		err = ErrInvalidPrivateKey
		return
	}

	eckey.PublicKey = asn1.BitString{
		BitLength: len(pkey) * 8,
		Bytes:     pkey,
	}
	out, err = asn1.Marshal(eckey)
	return
}

func HandleRegisterBasic(w http.ResponseWriter, r *http.Request) {
	fmt.Println("HandleRegisterBasic")
	tmpCurve := elliptic.P256()
	r.ParseMultipartForm(int64(100))
	step := strings.TrimSpace(r.PostFormValue("step"))
	//state := strings.TrimSpace(r.PostFormValue("state"))
	if step == "0" {
		//fmt.Println(step, ":", state)
		w.Header().Set("Content-Type", "application/json")
		preInfo, _ := json.Marshal(PreInfo{tmpCurve.Params().Gx.String(), tmpCurve.Params().Gy.String(), tmpCurve.Params().P.String(), tmpCurve.Params().B.String(), tmpCurve.Params().N.String()})
		//fmt.Println(string(preInfo))
		io.WriteString(w, string(preInfo))
	}
	if step == "1" {
		//fmt.Println(step, "::", state)
		pubKey := strings.TrimSpace(r.PostFormValue("pub_key"))
		fmt.Println(pubKey)
		uname := strings.TrimSpace(r.PostFormValue("uname"))
		key := strings.Split(pubKey, ",")
		pX := new(big.Int)
		pY := new(big.Int)
		pX.SetString(key[0], 10)
		pY.SetString(key[1], 10)
		dataB = elliptic.Marshal(tmpCurve, pX, pY)
		fmt.Println(">>>>>>>", uname)
		fmt.Println(">>>>>>>", dataB)

		storeData(uname, dataB)
		_, _ = getData(uname)
	}
}

//Update the named content
func (t Tag) Update(hashBytes HID, typeString string) Tag {
	t.Parents = Parents{t.Hash()}
	t.HashBytes = hashBytes
	t.TypeString = typeString
	//t.nameSegment = t.nameSegment
	t.Version = newVersion()
	//t.hkid = t.hkid
	prikey, err := geterPoster.getPrivateKeyForHkid(t.Hkid)
	if err != nil {
		log.Panic("You don't seem to own this Domain")
	}

	ObjectHash := t.genTagHash(
		t.HashBytes,
		t.TypeString,
		t.NameSegment,
		t.Version,
		t.Parents,
		t.Hkid,
	)
	ecdsaprikey := ecdsa.PrivateKey(*prikey)
	r, s, _ := ecdsa.Sign(rand.Reader, &ecdsaprikey, ObjectHash)
	t.Signature = elliptic.Marshal(elliptic.P521(), r, s)
	return t
}

//NewTag build a new tag with the initial content
func NewTag(
	HashBytes HID,
	TypeString string,
	nameSegment string,
	tparent Parents,
	hkid HKID,
) Tag {
	prikey, _ := geterPoster.getPrivateKeyForHkid(hkid)
	version := newVersion()
	if tparent == nil {
		tparent = Parents{Blob{}.Hash()}
	}
	ObjectHash := Tag{}.genTagHash(
		HashBytes,
		TypeString,
		nameSegment,
		version,
		tparent,
		hkid,
	)
	ecdsaprikey := ecdsa.PrivateKey(*prikey)
	r, s, _ := ecdsa.Sign(rand.Reader, &ecdsaprikey, ObjectHash)
	signature := elliptic.Marshal(elliptic.P521(), r, s)
	t := Tag{HashBytes,
		TypeString,
		nameSegment,
		version,
		tparent,
		hkid,
		signature}
	return t
}

func NewECDSAPublicKey(creationTime time.Time, pub *ecdsa.PublicKey) *PublicKey {
	pk := &PublicKey{
		CreationTime: creationTime,
		PubKeyAlgo:   PubKeyAlgoECDSA,
		PublicKey:    pub,
		ec:           new(ecdsaKey),
	}

	switch pub.Curve {
	case elliptic.P256():
		pk.ec.oid = oidCurveP256
	case elliptic.P384():
		pk.ec.oid = oidCurveP384
	case elliptic.P521():
		pk.ec.oid = oidCurveP521
	default:
		panic("unknown elliptic curve")
	}

	pk.ec.p.bytes = elliptic.Marshal(pub.Curve, pub.X, pub.Y)
	pk.ec.p.bitLength = uint16(8 * len(pk.ec.p.bytes))

	pk.setFingerPrintAndKeyId()
	return pk
}

func TestMessage(t *testing.T) {
	log := make(chan string, 100)
	priv, x, y := encryption.CreateKey(log)
	pub := elliptic.Marshal(elliptic.P256(), x, y)
	address := encryption.GetAddress(log, x, y)

	msg := new(Message)
	msg.AddrHash = MakeHash(address)
	msg.TxidHash = MakeHash([]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16})
	msg.Timestamp = time.Now().Round(time.Second)
	msg.Content = *encryption.Encrypt(log, pub, "Hello World!")

	mBytes := msg.GetBytes()
	if mBytes == nil {
		fmt.Println("Error Encoding Message!")
		t.FailNow()
	}

	msg2 := new(Message)
	msg2.FromBytes(mBytes)
	if string(msg2.AddrHash.GetBytes()) != string(msg.AddrHash.GetBytes()) || string(msg2.TxidHash.GetBytes()) != string(msg.TxidHash.GetBytes()) || msg2.Timestamp.Unix() != msg.Timestamp.Unix() {
		fmt.Println("Message Header incorrect: ", msg2)
		t.FailNow()
	}

	if string(encryption.Decrypt(log, priv, &msg.Content)[:12]) != "Hello World!" {
		fmt.Println("Message content incorrect: ", string(encryption.Decrypt(log, priv, &msg.Content)[:12]))
		t.Fail()
	}
}

// marshalECDSASHAVerifyingKeyV1 encodes a public key as a protobuf message.
func marshalECDSASHAVerifyingKeyV1(k *ecdsa.PublicKey) *ECDSA_SHA_VerifyingKeyV1 {
	return &ECDSA_SHA_VerifyingKeyV1{
		Curve:    NamedEllipticCurve_PRIME256_V1.Enum(),
		EcPublic: elliptic.Marshal(k.Curve, k.X, k.Y),
	}

}

func pubkeyDump(w indent.Writer, cert *x509.Certificate) {
	switch cert.PublicKeyAlgorithm {
	case x509.ECDSA:
		w.Printf("Public Key Algorithm: %s\n", w.Bold("ECDSA"))
		pub, ok := cert.PublicKey.(*ecdsa.PublicKey)
		if !ok {
			w.Println(w.Bold("[unrecognizable]"))
			return
		}
		w.Headerf("Public Key: (%s)\n", w.Bold("%d bits", pub.Params().BitSize))
		w.PrintHex(elliptic.Marshal(pub.Curve, pub.X, pub.Y))
		w.Dedent()
		w.Printf("Curve: %s\n", EcdsaCurveName[pub.Curve])
		return
	case x509.RSA:
		w.Printf("Public Key Algorithm: RSA\n")
	case x509.DSA:
		w.Printf("Public Key Algorithm: DSA\n")
	default:
		w.Printf("Public Key Algorithm: Unknown (type %d)\n", cert.PublicKeyAlgorithm)
	}
	b, err := x509.MarshalPKIXPublicKey(cert.PublicKey)
	w.Headerf("Public Key:\n")
	if err != nil {
		w.Printf("[unrecognizable]\n")
	} else {
		w.PrintHex(b)
	}
	w.Dedent()
}

func marshalPublicKey(pub interface{}) (publicKeyBytes []byte, publicKeyAlgorithm pkix.AlgorithmIdentifier, err error) {
	switch pub := pub.(type) {
	case *rsa.PublicKey:
		publicKeyBytes, err = asn1.Marshal(rsaPublicKey{
			N: pub.N,
			E: pub.E,
		})
		publicKeyAlgorithm.Algorithm = oidPublicKeyRSA
		// This is a NULL parameters value which is technically
		// superfluous, but most other code includes it and, by
		// doing this, we match their public key hashes.
		publicKeyAlgorithm.Parameters = asn1.RawValue{
			Tag: 5,
		}
	case *ecdsa.PublicKey:
		publicKeyBytes = elliptic.Marshal(pub.Curve, pub.X, pub.Y)
		oid, ok := oidFromNamedCurve(pub.Curve)
		if !ok {
			return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported elliptic curve")
		}
		publicKeyAlgorithm.Algorithm = oidPublicKeyECDSA
		var paramBytes []byte
		paramBytes, err = asn1.Marshal(oid)
		if err != nil {
			return
		}
		publicKeyAlgorithm.Parameters.FullBytes = paramBytes
	default:
		return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: only RSA and ECDSA public keys supported")
	}

	return publicKeyBytes, publicKeyAlgorithm, nil
}

// Encrypt secures and authenticates its input using the public key
// using ECDHE with AES-128-CBC-HMAC-SHA1.
func Encrypt(pub *ecdsa.PublicKey, in []byte) (out []byte, err error) {
	ephemeral, err := ecdsa.GenerateKey(Curve(), rand.Reader)
	if err != nil {
		return
	}
	x, _ := pub.Curve.ScalarMult(pub.X, pub.Y, ephemeral.D.Bytes())
	if x == nil {
		return nil, errors.New("Failed to generate encryption key")
	}
	shared := sha256.Sum256(x.Bytes())
	iv, err := symcrypt.MakeRandom(16)
	if err != nil {
		return
	}

	paddedIn := padding.AddPadding(in)
	ct, err := symcrypt.EncryptCBC(paddedIn, iv, shared[:16])
	if err != nil {
		return
	}

	ephPub := elliptic.Marshal(pub.Curve, ephemeral.PublicKey.X, ephemeral.PublicKey.Y)
	out = make([]byte, 1+len(ephPub)+16)
	out[0] = byte(len(ephPub))
	copy(out[1:], ephPub)
	copy(out[1+len(ephPub):], iv)
	out = append(out, ct...)

	h := hmac.New(sha1.New, shared[16:])
	h.Write(iv)
	h.Write(ct)
	out = h.Sum(out)
	return
}

// Convert ECC-256 Public Key to an EMP address (raw 25 bytes).
func GetAddress(log chan string, x, y *big.Int) []byte {
	pubKey := elliptic.Marshal(elliptic.P256(), x, y)
	ripemd := ripemd160.New()

	sum := sha512.Sum384(pubKey)
	sumslice := make([]byte, sha512.Size384, sha512.Size384)
	for i := 0; i < sha512.Size384; i++ {
		sumslice[i] = sum[i]
	}

	ripemd.Write(sumslice)
	appender := ripemd.Sum(nil)
	appender = appender[len(appender)-20:]
	address := make([]byte, 1, 1)

	// Version 0x01
	address[0] = 0x01
	address = append(address, appender...)

	sum = sha512.Sum384(address)
	sum = sha512.Sum384(sum[:])

	for i := 0; i < 4; i++ {
		address = append(address, sum[i])
	}

	return address
}

// FIXME(dlg): This is hideous.
func arrayForPublicKey(pub *ecdsa.PublicKey) string {
	raw := elliptic.Marshal(pub.Curve, pub.X, pub.Y)
	vals := make([]string, len(raw))
	for i, b := range raw {
		vals[i] = strconv.Itoa(int(b))
	}
	return "[" + strings.Join(vals, ", ") + "]"
}

func (e *ellipticECDHCurve) offer(rand io.Reader) (publicKey []byte, err error) {
	var x, y *big.Int
	e.privateKey, x, y, err = elliptic.GenerateKey(e.curve, rand)
	if err != nil {
		return nil, err
	}
	return elliptic.Marshal(e.curve, x, y), nil
}