// Copyright 2020 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package rlpx

import (
	"bytes"
	"crypto/ecdsa"
	"encoding/hex"
	"fmt"
	"io"
	"math/rand"
	"net"
	"reflect"
	"strings"
	"testing"

	"github.com/davecgh/go-spew/spew"
	"github.com/ledgerwatch/erigon/crypto"
	"github.com/ledgerwatch/erigon/crypto/ecies"
	"github.com/ledgerwatch/erigon/p2p/simulations/pipes"
	"github.com/ledgerwatch/erigon/rlp"
	"github.com/stretchr/testify/assert"
)

type message struct {
	code uint64
	data []byte
	err  error
}

func TestHandshake(t *testing.T) {
	p1, p2 := createPeers(t)
	p1.Close()
	p2.Close()
}

// This test checks that messages can be sent and received through WriteMsg/ReadMsg.
func TestReadWriteMsg(t *testing.T) {
	peer1, peer2 := createPeers(t)
	defer peer1.Close()
	defer peer2.Close()

	testCode := uint64(23)
	testData := []byte("test")
	checkMsgReadWrite(t, peer1, peer2, testCode, testData)

	t.Log("enabling snappy")
	peer1.SetSnappy(true)
	peer2.SetSnappy(true)
	checkMsgReadWrite(t, peer1, peer2, testCode, testData)
}

func checkMsgReadWrite(t *testing.T, p1, p2 *Conn, msgCode uint64, msgData []byte) {
	// Set up the reader.
	ch := make(chan message, 1)
	go func() {
		var msg message
		msg.code, msg.data, _, msg.err = p1.Read()
		ch <- msg
	}()

	// Write the message.
	_, err := p2.Write(msgCode, msgData)
	if err != nil {
		t.Fatal(err)
	}

	// Check it was received correctly.
	msg := <-ch
	assert.Equal(t, msgCode, msg.code, "wrong message code returned from ReadMsg")
	assert.Equal(t, msgData, msg.data, "wrong message data returned from ReadMsg")
}

func createPeers(t *testing.T) (peer1, peer2 *Conn) {
	conn1, conn2 := net.Pipe()
	key1, key2 := newkey(), newkey()
	peer1 = NewConn(conn1, &key2.PublicKey) // dialer
	peer2 = NewConn(conn2, nil)             // listener
	doHandshake(t, peer1, peer2, key1, key2)
	return peer1, peer2
}

func doHandshake(t *testing.T, peer1, peer2 *Conn, key1, key2 *ecdsa.PrivateKey) {
	keyChan := make(chan *ecdsa.PublicKey, 1)
	go func() {
		pubKey, err := peer2.Handshake(key2)
		if err != nil {
			t.Errorf("peer2 could not do handshake: %v", err)
		}
		keyChan <- pubKey
	}()

	pubKey2, err := peer1.Handshake(key1)
	if err != nil {
		t.Errorf("peer1 could not do handshake: %v", err)
	}
	pubKey1 := <-keyChan

	// Confirm the handshake was successful.
	if !reflect.DeepEqual(pubKey1, &key1.PublicKey) || !reflect.DeepEqual(pubKey2, &key2.PublicKey) {
		t.Fatal("unsuccessful handshake")
	}
}

// This test checks the frame data of written messages.
func TestFrameReadWrite(t *testing.T) {
	conn := NewConn(nil, nil)
	hash := fakeHash([]byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1})
	conn.InitWithSecrets(Secrets{
		AES:        crypto.Keccak256(),
		MAC:        crypto.Keccak256(),
		IngressMAC: hash,
		EgressMAC:  hash,
	})
	h := conn.session

	golden := unhex(`
		00828ddae471818bb0bfa6b551d1cb42
		01010101010101010101010101010101
		ba628a4ba590cb43f7848f41c4382885
		01010101010101010101010101010101
	`)
	msgCode := uint64(8)
	msg := []uint{1, 2, 3, 4}
	msgEnc, _ := rlp.EncodeToBytes(msg)

	// Check writeFrame. The frame that's written should be equal to the test vector.
	buf := new(bytes.Buffer)
	if err := h.writeFrame(buf, msgCode, msgEnc); err != nil {
		t.Fatalf("WriteMsg error: %v", err)
	}
	if !bytes.Equal(buf.Bytes(), golden) {
		t.Fatalf("output mismatch:\n  got:  %x\n  want: %x", buf.Bytes(), golden)
	}

	// Check readFrame on the test vector.
	content, err := h.readFrame(bytes.NewReader(golden))
	if err != nil {
		t.Fatalf("ReadMsg error: %v", err)
	}
	wantContent := unhex("08C401020304")
	if !bytes.Equal(content, wantContent) {
		t.Errorf("frame content mismatch:\ngot  %x\nwant %x", content, wantContent)
	}
}

type fakeHash []byte

func (fakeHash) Write(p []byte) (int, error) { return len(p), nil }
func (fakeHash) Reset()                      {}
func (fakeHash) BlockSize() int              { return 0 }
func (h fakeHash) Size() int                 { return len(h) }
func (h fakeHash) Sum(b []byte) []byte       { return append(b, h...) }

type handshakeAuthTest struct {
	input       string
	wantVersion uint
	wantRest    []rlp.RawValue
}

var eip8HandshakeAuthTests = []handshakeAuthTest{
	// (Auth₂) EIP-8 encoding
	{
		input: `
			01b304ab7578555167be8154d5cc456f567d5ba302662433674222360f08d5f1534499d3678b513b
			0fca474f3a514b18e75683032eb63fccb16c156dc6eb2c0b1593f0d84ac74f6e475f1b8d56116b84
			9634a8c458705bf83a626ea0384d4d7341aae591fae42ce6bd5c850bfe0b999a694a49bbbaf3ef6c
			da61110601d3b4c02ab6c30437257a6e0117792631a4b47c1d52fc0f8f89caadeb7d02770bf999cc
			147d2df3b62e1ffb2c9d8c125a3984865356266bca11ce7d3a688663a51d82defaa8aad69da39ab6
			d5470e81ec5f2a7a47fb865ff7cca21516f9299a07b1bc63ba56c7a1a892112841ca44b6e0034dee
			70c9adabc15d76a54f443593fafdc3b27af8059703f88928e199cb122362a4b35f62386da7caad09
			c001edaeb5f8a06d2b26fb6cb93c52a9fca51853b68193916982358fe1e5369e249875bb8d0d0ec3
			6f917bc5e1eafd5896d46bd61ff23f1a863a8a8dcd54c7b109b771c8e61ec9c8908c733c0263440e
			2aa067241aaa433f0bb053c7b31a838504b148f570c0ad62837129e547678c5190341e4f1693956c
			3bf7678318e2d5b5340c9e488eefea198576344afbdf66db5f51204a6961a63ce072c8926c
		`,
		wantVersion: 4,
		wantRest:    []rlp.RawValue{},
	},
	// (Auth₃) RLPx v4 EIP-8 encoding with version 56, additional list elements
	{
		input: `
			01b8044c6c312173685d1edd268aa95e1d495474c6959bcdd10067ba4c9013df9e40ff45f5bfd6f7
			2471f93a91b493f8e00abc4b80f682973de715d77ba3a005a242eb859f9a211d93a347fa64b597bf
			280a6b88e26299cf263b01b8dfdb712278464fd1c25840b995e84d367d743f66c0e54a586725b7bb
			f12acca27170ae3283c1073adda4b6d79f27656993aefccf16e0d0409fe07db2dc398a1b7e8ee93b
			cd181485fd332f381d6a050fba4c7641a5112ac1b0b61168d20f01b479e19adf7fdbfa0905f63352
			bfc7e23cf3357657455119d879c78d3cf8c8c06375f3f7d4861aa02a122467e069acaf513025ff19
			6641f6d2810ce493f51bee9c966b15c5043505350392b57645385a18c78f14669cc4d960446c1757
			1b7c5d725021babbcd786957f3d17089c084907bda22c2b2675b4378b114c601d858802a55345a15
			116bc61da4193996187ed70d16730e9ae6b3bb8787ebcaea1871d850997ddc08b4f4ea668fbf3740
			7ac044b55be0908ecb94d4ed172ece66fd31bfdadf2b97a8bc690163ee11f5b575a4b44e36e2bfb2
			f0fce91676fd64c7773bac6a003f481fddd0bae0a1f31aa27504e2a533af4cef3b623f4791b2cca6
			d490
		`,
		wantVersion: 56,
		wantRest:    []rlp.RawValue{{0x01}, {0x02}, {0xC2, 0x04, 0x05}},
	},
}

type handshakeAckTest struct {
	input       string
	wantVersion uint
	wantRest    []rlp.RawValue
}

var eip8HandshakeRespTests = []handshakeAckTest{
	// (Ack₂) EIP-8 encoding
	{
		input: `
			01ea0451958701280a56482929d3b0757da8f7fbe5286784beead59d95089c217c9b917788989470
			b0e330cc6e4fb383c0340ed85fab836ec9fb8a49672712aeabbdfd1e837c1ff4cace34311cd7f4de
			05d59279e3524ab26ef753a0095637ac88f2b499b9914b5f64e143eae548a1066e14cd2f4bd7f814
			c4652f11b254f8a2d0191e2f5546fae6055694aed14d906df79ad3b407d94692694e259191cde171
			ad542fc588fa2b7333313d82a9f887332f1dfc36cea03f831cb9a23fea05b33deb999e85489e645f
			6aab1872475d488d7bd6c7c120caf28dbfc5d6833888155ed69d34dbdc39c1f299be1057810f34fb
			e754d021bfca14dc989753d61c413d261934e1a9c67ee060a25eefb54e81a4d14baff922180c395d
			3f998d70f46f6b58306f969627ae364497e73fc27f6d17ae45a413d322cb8814276be6ddd13b885b
			201b943213656cde498fa0e9ddc8e0b8f8a53824fbd82254f3e2c17e8eaea009c38b4aa0a3f306e8
			797db43c25d68e86f262e564086f59a2fc60511c42abfb3057c247a8a8fe4fb3ccbadde17514b7ac
			8000cdb6a912778426260c47f38919a91f25f4b5ffb455d6aaaf150f7e5529c100ce62d6d92826a7
			1778d809bdf60232ae21ce8a437eca8223f45ac37f6487452ce626f549b3b5fdee26afd2072e4bc7
			5833c2464c805246155289f4
		`,
		wantVersion: 4,
		wantRest:    []rlp.RawValue{},
	},
	// (Ack₃) EIP-8 encoding with version 57, additional list elements
	{
		input: `
			01f004076e58aae772bb101ab1a8e64e01ee96e64857ce82b1113817c6cdd52c09d26f7b90981cd7
			ae835aeac72e1573b8a0225dd56d157a010846d888dac7464baf53f2ad4e3d584531fa203658fab0
			3a06c9fd5e35737e417bc28c1cbf5e5dfc666de7090f69c3b29754725f84f75382891c561040ea1d
			dc0d8f381ed1b9d0d4ad2a0ec021421d847820d6fa0ba66eaf58175f1b235e851c7e2124069fbc20
			2888ddb3ac4d56bcbd1b9b7eab59e78f2e2d400905050f4a92dec1c4bdf797b3fc9b2f8e84a482f3
			d800386186712dae00d5c386ec9387a5e9c9a1aca5a573ca91082c7d68421f388e79127a5177d4f8
			590237364fd348c9611fa39f78dcdceee3f390f07991b7b47e1daa3ebcb6ccc9607811cb17ce51f1
			c8c2c5098dbdd28fca547b3f58c01a424ac05f869f49c6a34672ea2cbbc558428aa1fe48bbfd6115
			8b1b735a65d99f21e70dbc020bfdface9f724a0d1fb5895db971cc81aa7608baa0920abb0a565c9c
			436e2fd13323428296c86385f2384e408a31e104670df0791d93e743a3a5194ee6b076fb6323ca59
			3011b7348c16cf58f66b9633906ba54a2ee803187344b394f75dd2e663a57b956cb830dd7a908d4f
			39a2336a61ef9fda549180d4ccde21514d117b6c6fd07a9102b5efe710a32af4eeacae2cb3b1dec0
			35b9593b48b9d3ca4c13d245d5f04169b0b1
		`,
		wantVersion: 57,
		wantRest:    []rlp.RawValue{{0x06}, {0xC2, 0x07, 0x08}, {0x81, 0xFA}},
	},
}

var (
	keyA, _ = crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee")
	keyB, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
)

func TestHandshakeForwardCompatibility(t *testing.T) {
	var (
		pubA          = crypto.FromECDSAPub(&keyA.PublicKey)[1:]
		pubB          = crypto.FromECDSAPub(&keyB.PublicKey)[1:]
		ephA, _       = crypto.HexToECDSA("869d6ecf5211f1cc60418a13b9d870b22959d0c16f02bec714c960dd2298a32d")
		ephB, _       = crypto.HexToECDSA("e238eb8e04fee6511ab04c6dd3c89ce097b11f25d584863ac2b6d5b35b1847e4")
		ephPubA       = crypto.FromECDSAPub(&ephA.PublicKey)[1:]
		ephPubB       = crypto.FromECDSAPub(&ephB.PublicKey)[1:]
		nonceA        = unhex("7e968bba13b6c50e2c4cd7f241cc0d64d1ac25c7f5952df231ac6a2bda8ee5d6")
		nonceB        = unhex("559aead08264d5795d3909718cdd05abd49572e84fe55590eef31a88a08fdffd")
		_, _, _, _    = pubA, pubB, ephPubA, ephPubB
		authSignature = unhex("299ca6acfd35e3d72d8ba3d1e2b60b5561d5af5218eb5bc182045769eb4226910a301acae3b369fffc4a4899d6b02531e89fd4fe36a2cf0d93607ba470b50f7800")
		_             = authSignature
	)
	makeAuth := func(test handshakeAuthTest) *authMsgV4 {
		msg := &authMsgV4{Version: test.wantVersion, Rest: test.wantRest}
		copy(msg.Signature[:], authSignature)
		copy(msg.InitiatorPubkey[:], pubA)
		copy(msg.Nonce[:], nonceA)
		return msg
	}
	makeAck := func(test handshakeAckTest) *authRespV4 {
		msg := &authRespV4{Version: test.wantVersion, Rest: test.wantRest}
		copy(msg.RandomPubkey[:], ephPubB)
		copy(msg.Nonce[:], nonceB)
		return msg
	}

	// check auth msg parsing
	for _, test := range eip8HandshakeAuthTests {
		var h handshakeState
		r := bytes.NewReader(unhex(test.input))
		msg := new(authMsgV4)
		ciphertext, err := h.readMsg(msg, keyB, r)
		if err != nil {
			t.Errorf("error for input %x:\n  %v", unhex(test.input), err)
			continue
		}
		if !bytes.Equal(ciphertext, unhex(test.input)) {
			t.Errorf("wrong ciphertext for input %x:\n  %x", unhex(test.input), ciphertext)
		}
		want := makeAuth(test)
		if !reflect.DeepEqual(msg, want) {
			t.Errorf("wrong msg for input %x:\ngot %s\nwant %s", unhex(test.input), spew.Sdump(msg), spew.Sdump(want))
		}
	}

	// check auth resp parsing
	for _, test := range eip8HandshakeRespTests {
		var h handshakeState
		input := unhex(test.input)
		r := bytes.NewReader(input)
		msg := new(authRespV4)
		ciphertext, err := h.readMsg(msg, keyA, r)
		if err != nil {
			t.Errorf("error for input %x:\n  %v", input, err)
			continue
		}
		if !bytes.Equal(ciphertext, input) {
			t.Errorf("wrong ciphertext for input %x:\n  %x", input, err)
		}
		want := makeAck(test)
		if !reflect.DeepEqual(msg, want) {
			t.Errorf("wrong msg for input %x:\ngot %s\nwant %s", input, spew.Sdump(msg), spew.Sdump(want))
		}
	}

	// check derivation for (Auth₂, Ack₂) on recipient side
	var (
		hs = &handshakeState{
			initiator:     false,
			respNonce:     nonceB,
			randomPrivKey: ecies.ImportECDSA(ephB),
		}
		authCiphertext     = unhex(eip8HandshakeAuthTests[0].input)
		authRespCiphertext = unhex(eip8HandshakeRespTests[0].input)
		authMsg            = makeAuth(eip8HandshakeAuthTests[0])
		wantAES            = unhex("80e8632c05fed6fc2a13b0f8d31a3cf645366239170ea067065aba8e28bac487")
		wantMAC            = unhex("2ea74ec5dae199227dff1af715362700e989d889d7a493cb0639691efb8e5f98")
		wantFooIngressHash = unhex("0c7ec6340062cc46f5e9f1e3cf86f8c8c403c5a0964f5df0ebd34a75ddc86db5")
	)
	if err := hs.handleAuthMsg(authMsg, keyB); err != nil {
		t.Fatalf("handleAuthMsg: %v", err)
	}
	derived, err := hs.secrets(authCiphertext, authRespCiphertext)
	if err != nil {
		t.Fatalf("secrets: %v", err)
	}
	if !bytes.Equal(derived.AES, wantAES) {
		t.Errorf("aes-secret mismatch:\ngot %x\nwant %x", derived.AES, wantAES)
	}
	if !bytes.Equal(derived.MAC, wantMAC) {
		t.Errorf("mac-secret mismatch:\ngot %x\nwant %x", derived.MAC, wantMAC)
	}
	io.WriteString(derived.IngressMAC, "foo")
	fooIngressHash := derived.IngressMAC.Sum(nil)
	if !bytes.Equal(fooIngressHash, wantFooIngressHash) {
		t.Errorf("ingress-mac('foo') mismatch:\ngot %x\nwant %x", fooIngressHash, wantFooIngressHash)
	}
}

func BenchmarkHandshakeRead(b *testing.B) {
	var input = unhex(eip8HandshakeAuthTests[0].input)

	for i := 0; i < b.N; i++ {
		var (
			h   handshakeState
			r   = bytes.NewReader(input)
			msg = new(authMsgV4)
		)
		if _, err := h.readMsg(msg, keyB, r); err != nil {
			b.Fatal(err)
		}
	}
}

func BenchmarkThroughput(b *testing.B) {
	pipe1, pipe2, err := pipes.TCPPipe()
	if err != nil {
		b.Fatal(err)
	}

	var (
		conn1, conn2  = NewConn(pipe1, nil), NewConn(pipe2, &keyA.PublicKey)
		handshakeDone = make(chan error, 1)
		msgdata       = make([]byte, 1024)
		rand          = rand.New(rand.NewSource(1337))
	)
	rand.Read(msgdata)

	// Server side.
	go func() {
		defer conn1.Close()
		// Perform handshake.
		_, err := conn1.Handshake(keyA)
		handshakeDone <- err
		if err != nil {
			return
		}
		conn1.SetSnappy(true)
		// Keep sending messages until connection closed.
		for {
			if _, err := conn1.Write(0, msgdata); err != nil {
				return
			}
		}
	}()

	// Set up client side.
	defer conn2.Close()
	if _, err := conn2.Handshake(keyB); err != nil {
		b.Fatal("client handshake error:", err)
	}
	conn2.SetSnappy(true)
	if err := <-handshakeDone; err != nil {
		b.Fatal("server hanshake error:", err)
	}

	// Read N messages.
	b.SetBytes(int64(len(msgdata)))
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		_, _, _, err := conn2.Read()
		if err != nil {
			b.Fatal("read error:", err)
		}
	}
}

func unhex(str string) []byte {
	r := strings.NewReplacer("\t", "", " ", "", "\n", "")
	b, err := hex.DecodeString(r.Replace(str))
	if err != nil {
		panic(fmt.Sprintf("invalid hex string: %q", str))
	}
	return b
}

func newkey() *ecdsa.PrivateKey {
	key, err := crypto.GenerateKey()
	if err != nil {
		panic("couldn't generate key: " + err.Error())
	}
	return key
}