// 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 v4wire

import (
	"encoding/hex"
	"net"
	"reflect"
	"testing"

	"github.com/davecgh/go-spew/spew"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/rlp"
)

// EIP-8 test vectors.
var testPackets = []struct {
	input      string
	wantPacket interface{}
}{
	{
		input: "71dbda3a79554728d4f94411e42ee1f8b0d561c10e1e5f5893367948c6a7d70bb87b235fa28a77070271b6c164a2dce8c7e13a5739b53b5e96f2e5acb0e458a02902f5965d55ecbeb2ebb6cabb8b2b232896a36b737666c55265ad0a68412f250001ea04cb847f000001820cfa8215a8d790000000000000000000000000000000018208ae820d058443b9a355",
		wantPacket: &Ping{
			Version:    4,
			From:       Endpoint{net.ParseIP("127.0.0.1").To4(), 3322, 5544},
			To:         Endpoint{net.ParseIP("::1"), 2222, 3333},
			Expiration: 1136239445,
		},
	},
	{
		input: "e9614ccfd9fc3e74360018522d30e1419a143407ffcce748de3e22116b7e8dc92ff74788c0b6663aaa3d67d641936511c8f8d6ad8698b820a7cf9e1be7155e9a241f556658c55428ec0563514365799a4be2be5a685a80971ddcfa80cb422cdd0101ec04cb847f000001820cfa8215a8d790000000000000000000000000000000018208ae820d058443b9a3550102",
		wantPacket: &Ping{
			Version:    4,
			From:       Endpoint{net.ParseIP("127.0.0.1").To4(), 3322, 5544},
			To:         Endpoint{net.ParseIP("::1"), 2222, 3333},
			Expiration: 1136239445,
			ENRSeq:     1,
			Rest:       []rlp.RawValue{{0x02}},
		},
	},
	{
		input: "c7c44041b9f7c7e41934417ebac9a8e1a4c6298f74553f2fcfdcae6ed6fe53163eb3d2b52e39fe91831b8a927bf4fc222c3902202027e5e9eb812195f95d20061ef5cd31d502e47ecb61183f74a504fe04c51e73df81f25c4d506b26db4517490103f84eb840ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd31387574077f301b421bc84df7266c44e9e6d569fc56be00812904767bf5ccd1fc7f8443b9a35582999983999999280dc62cc8255c73471e0a61da0c89acdc0e035e260add7fc0c04ad9ebf3919644c91cb247affc82b69bd2ca235c71eab8e49737c937a2c396",
		wantPacket: &Findnode{
			Target:     hexPubkey("ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd31387574077f301b421bc84df7266c44e9e6d569fc56be00812904767bf5ccd1fc7f"),
			Expiration: 1136239445,
			Rest:       []rlp.RawValue{{0x82, 0x99, 0x99}, {0x83, 0x99, 0x99, 0x99}},
		},
	},
	{
		input: "c679fc8fe0b8b12f06577f2e802d34f6fa257e6137a995f6f4cbfc9ee50ed3710faf6e66f932c4c8d81d64343f429651328758b47d3dbc02c4042f0fff6946a50f4a49037a72bb550f3a7872363a83e1b9ee6469856c24eb4ef80b7535bcf99c0004f9015bf90150f84d846321163782115c82115db8403155e1427f85f10a5c9a7755877748041af1bcd8d474ec065eb33df57a97babf54bfd2103575fa829115d224c523596b401065a97f74010610fce76382c0bf32f84984010203040101b840312c55512422cf9b8a4097e9a6ad79402e87a15ae909a4bfefa22398f03d20951933beea1e4dfa6f968212385e829f04c2d314fc2d4e255e0d3bc08792b069dbf8599020010db83c4d001500000000abcdef12820d05820d05b84038643200b172dcfef857492156971f0e6aa2c538d8b74010f8e140811d53b98c765dd2d96126051913f44582e8c199ad7c6d6819e9a56483f637feaac9448aacf8599020010db885a308d313198a2e037073488203e78203e8b8408dcab8618c3253b558d459da53bd8fa68935a719aff8b811197101a4b2b47dd2d47295286fc00cc081bb542d760717d1bdd6bec2c37cd72eca367d6dd3b9df738443b9a355010203b525a138aa34383fec3d2719a0",
		wantPacket: &Neighbors{
			Nodes: []Node{
				{
					ID:  hexPubkey("3155e1427f85f10a5c9a7755877748041af1bcd8d474ec065eb33df57a97babf54bfd2103575fa829115d224c523596b401065a97f74010610fce76382c0bf32"),
					IP:  net.ParseIP("99.33.22.55").To4(),
					UDP: 4444,
					TCP: 4445,
				},
				{
					ID:  hexPubkey("312c55512422cf9b8a4097e9a6ad79402e87a15ae909a4bfefa22398f03d20951933beea1e4dfa6f968212385e829f04c2d314fc2d4e255e0d3bc08792b069db"),
					IP:  net.ParseIP("1.2.3.4").To4(),
					UDP: 1,
					TCP: 1,
				},
				{
					ID:  hexPubkey("38643200b172dcfef857492156971f0e6aa2c538d8b74010f8e140811d53b98c765dd2d96126051913f44582e8c199ad7c6d6819e9a56483f637feaac9448aac"),
					IP:  net.ParseIP("2001:db8:3c4d:15::abcd:ef12"),
					UDP: 3333,
					TCP: 3333,
				},
				{
					ID:  hexPubkey("8dcab8618c3253b558d459da53bd8fa68935a719aff8b811197101a4b2b47dd2d47295286fc00cc081bb542d760717d1bdd6bec2c37cd72eca367d6dd3b9df73"),
					IP:  net.ParseIP("2001:db8:85a3:8d3:1319:8a2e:370:7348"),
					UDP: 999,
					TCP: 1000,
				},
			},
			Expiration: 1136239445,
			Rest:       []rlp.RawValue{{0x01}, {0x02}, {0x03}},
		},
	},
}

// This test checks that the decoder accepts packets according to EIP-8.
func TestForwardCompatibility(t *testing.T) {
	testkey, _ := crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
	wantNodeKey := EncodePubkey(&testkey.PublicKey)

	for _, test := range testPackets {
		input, err := hex.DecodeString(test.input)
		if err != nil {
			t.Fatalf("invalid hex: %s", test.input)
		}
		packet, nodekey, _, err := Decode(input)
		if err != nil {
			t.Errorf("did not accept packet %s\n%v", test.input, err)
			continue
		}
		if !reflect.DeepEqual(packet, test.wantPacket) {
			t.Errorf("got %s\nwant %s", spew.Sdump(packet), spew.Sdump(test.wantPacket))
		}
		if nodekey != wantNodeKey {
			t.Errorf("got id %v\nwant id %v", nodekey, wantNodeKey)
		}
	}
}

func hexPubkey(h string) (ret Pubkey) {
	b, err := hex.DecodeString(h)
	if err != nil {
		panic(err)
	}
	if len(b) != len(ret) {
		panic("invalid length")
	}
	copy(ret[:], b)
	return ret
}