package ibftengine

import (
	"bytes"
	"reflect"
	"testing"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/consensus/istanbul"
	istanbulcommon "github.com/ethereum/go-ethereum/consensus/istanbul/common"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestEngine(t *testing.T) {
	engine := NewEngine(nil, common.Address{}, nil)
	require.NotNil(t, engine, "Constructor")
	assert.Implements(t, new(istanbul.Engine), engine)
}

func TestPrepareExtra(t *testing.T) {
	validators := make([]common.Address, 4)
	validators[0] = common.BytesToAddress(hexutil.MustDecode("0x44add0ec310f115a0e603b2d7db9f067778eaf8a"))
	validators[1] = common.BytesToAddress(hexutil.MustDecode("0x294fc7e8f22b3bcdcf955dd7ff3ba2ed833f8212"))
	validators[2] = common.BytesToAddress(hexutil.MustDecode("0x6beaaed781d2d2ab6350f5c4566a2c6eaac407a6"))
	validators[3] = common.BytesToAddress(hexutil.MustDecode("0x8be76812f765c24641ec63dc2852b378aba2b440"))

	vanity := make([]byte, types.IstanbulExtraVanity)
	expectedResult := append(vanity, hexutil.MustDecode("0xf858f8549444add0ec310f115a0e603b2d7db9f067778eaf8a94294fc7e8f22b3bcdcf955dd7ff3ba2ed833f8212946beaaed781d2d2ab6350f5c4566a2c6eaac407a6948be76812f765c24641ec63dc2852b378aba2b44080c0")...)

	h := &types.Header{
		Extra: vanity,
	}

	payload, err := prepareExtra(h, validators)
	if err != nil {
		t.Errorf("error mismatch: have %v, want: nil", err)
	}
	if !reflect.DeepEqual(payload, expectedResult) {
		t.Errorf("payload mismatch: have %v, want %v", payload, expectedResult)
	}

	// append useless information to extra-data
	h.Extra = append(vanity, make([]byte, 15)...)

	payload, _ = prepareExtra(h, validators)
	if !reflect.DeepEqual(payload, expectedResult) {
		t.Errorf("payload mismatch: have %v, want %v", payload, expectedResult)
	}
}

func TestWriteSeal(t *testing.T) {
	vanity := bytes.Repeat([]byte{0x00}, types.IstanbulExtraVanity)
	istRawData := hexutil.MustDecode("0xf858f8549444add0ec310f115a0e603b2d7db9f067778eaf8a94294fc7e8f22b3bcdcf955dd7ff3ba2ed833f8212946beaaed781d2d2ab6350f5c4566a2c6eaac407a6948be76812f765c24641ec63dc2852b378aba2b44080c0")
	expectedSeal := append([]byte{1, 2, 3}, bytes.Repeat([]byte{0x00}, types.IstanbulExtraSeal-3)...)
	expectedIstExtra := &types.IstanbulExtra{
		Validators: []common.Address{
			common.BytesToAddress(hexutil.MustDecode("0x44add0ec310f115a0e603b2d7db9f067778eaf8a")),
			common.BytesToAddress(hexutil.MustDecode("0x294fc7e8f22b3bcdcf955dd7ff3ba2ed833f8212")),
			common.BytesToAddress(hexutil.MustDecode("0x6beaaed781d2d2ab6350f5c4566a2c6eaac407a6")),
			common.BytesToAddress(hexutil.MustDecode("0x8be76812f765c24641ec63dc2852b378aba2b440")),
		},
		Seal:          expectedSeal,
		CommittedSeal: [][]byte{},
	}
	var expectedErr error

	h := &types.Header{
		Extra: append(vanity, istRawData...),
	}

	// normal case
	err := writeSeal(h, expectedSeal)
	if err != expectedErr {
		t.Errorf("error mismatch: have %v, want %v", err, expectedErr)
	}

	// verify istanbul extra-data
	istExtra, err := types.ExtractIstanbulExtra(h)
	if err != nil {
		t.Errorf("error mismatch: have %v, want nil", err)
	}
	if !reflect.DeepEqual(istExtra, expectedIstExtra) {
		t.Errorf("extra data mismatch: have %v, want %v", istExtra, expectedIstExtra)
	}

	// invalid seal
	unexpectedSeal := append(expectedSeal, make([]byte, 1)...)
	err = writeSeal(h, unexpectedSeal)
	if err != istanbulcommon.ErrInvalidSignature {
		t.Errorf("error mismatch: have %v, want %v", err, istanbulcommon.ErrInvalidSignature)
	}
}

func TestWriteCommittedSeals(t *testing.T) {
	vanity := bytes.Repeat([]byte{0x00}, types.IstanbulExtraVanity)
	istRawData := hexutil.MustDecode("0xf858f8549444add0ec310f115a0e603b2d7db9f067778eaf8a94294fc7e8f22b3bcdcf955dd7ff3ba2ed833f8212946beaaed781d2d2ab6350f5c4566a2c6eaac407a6948be76812f765c24641ec63dc2852b378aba2b44080c0")
	expectedCommittedSeal := append([]byte{1, 2, 3}, bytes.Repeat([]byte{0x00}, types.IstanbulExtraSeal-3)...)
	expectedIstExtra := &types.IstanbulExtra{
		Validators: []common.Address{
			common.BytesToAddress(hexutil.MustDecode("0x44add0ec310f115a0e603b2d7db9f067778eaf8a")),
			common.BytesToAddress(hexutil.MustDecode("0x294fc7e8f22b3bcdcf955dd7ff3ba2ed833f8212")),
			common.BytesToAddress(hexutil.MustDecode("0x6beaaed781d2d2ab6350f5c4566a2c6eaac407a6")),
			common.BytesToAddress(hexutil.MustDecode("0x8be76812f765c24641ec63dc2852b378aba2b440")),
		},
		Seal:          []byte{},
		CommittedSeal: [][]byte{expectedCommittedSeal},
	}
	var expectedErr error

	h := &types.Header{
		Extra: append(vanity, istRawData...),
	}

	// normal case
	err := writeCommittedSeals(h, [][]byte{expectedCommittedSeal})
	if err != expectedErr {
		t.Errorf("error mismatch: have %v, want %v", err, expectedErr)
	}

	// verify istanbul extra-data
	istExtra, err := types.ExtractIstanbulExtra(h)
	if err != nil {
		t.Errorf("error mismatch: have %v, want nil", err)
	}
	if !reflect.DeepEqual(istExtra, expectedIstExtra) {
		t.Errorf("extra data mismatch: have %v, want %v", istExtra, expectedIstExtra)
	}

	// invalid seal
	unexpectedCommittedSeal := append(expectedCommittedSeal, make([]byte, 1)...)
	err = writeCommittedSeals(h, [][]byte{unexpectedCommittedSeal})
	if err != istanbulcommon.ErrInvalidCommittedSeals {
		t.Errorf("error mismatch: have %v, want %v", err, istanbulcommon.ErrInvalidCommittedSeals)
	}
}