// Copyright 2018 The dexon-consensus Authors
// This file is part of the dexon-consensus library.
//
// The dexon-consensus 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 dexon-consensus 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 dexon-consensus library. If not, see
// <http://www.gnu.org/licenses/>.

package vm

import (
	"bytes"
	"errors"
	"math/big"
	"sort"
	"strings"

	"github.com/dexon-foundation/dexon/accounts/abi"
	"github.com/dexon-foundation/dexon/common"
	"github.com/dexon-foundation/dexon/core/types"
	"github.com/dexon-foundation/dexon/crypto"
	"github.com/dexon-foundation/dexon/params"
	"github.com/dexon-foundation/dexon/rlp"

	coreCommon "github.com/dexon-foundation/dexon-consensus/common"
	"github.com/dexon-foundation/dexon-consensus/core"
	coreCrypto "github.com/dexon-foundation/dexon-consensus/core/crypto"
	coreUtils "github.com/dexon-foundation/dexon-consensus/core/utils"

	"github.com/dexon-foundation/dexon-consensus/core/crypto/ecdsa"
	coreTypes "github.com/dexon-foundation/dexon-consensus/core/types"
	dkgTypes "github.com/dexon-foundation/dexon-consensus/core/types/dkg"
)

var GovernanceContractAddress = common.HexToAddress("63751838d6485578b23e8b051d40861ecc416794")

var abiObject abi.ABI
var GovernanceContractName2Method map[string]abi.Method
var sig2Method map[string]abi.Method
var events map[string]abi.Event

type Bytes32 [32]byte

type ReportType uint64

const (
	ReportTypeInvalidDKG = iota
	ReportTypeForkVote
	ReportTypeForkBlock
)

func init() {
	var err error

	// Parse governance contract ABI.
	abiObject, err = abi.JSON(strings.NewReader(GovernanceABIJSON))
	if err != nil {
		panic(err)
	}

	sig2Method = make(map[string]abi.Method)
	GovernanceContractName2Method = make(map[string]abi.Method)

	// Construct dispatch table.
	for _, method := range abiObject.Methods {
		sig2Method[string(method.Id())] = method
		GovernanceContractName2Method[method.Name] = method
	}

	events = make(map[string]abi.Event)

	// Event cache.
	for _, event := range abiObject.Events {
		events[event.Name] = event
	}
}

// RunGovernanceContract executes governance contract.
func RunGovernanceContract(evm *EVM, input []byte, contract *Contract) (ret []byte, err error) {
	if len(input) < 4 {
		return nil, nil
	}

	// Parse input.
	method, exists := sig2Method[string(input[:4])]
	if !exists {
		return nil, errExecutionReverted
	}

	// Dispatch method call.
	g := newGovernanceContract(evm, contract)
	arguments := input[4:]

	switch method.Name {
	case "addDKGComplaint":
		args := struct {
			Round     *big.Int
			Complaint []byte
		}{}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.addDKGComplaint(args.Round, args.Complaint)
	case "addDKGMasterPublicKey":
		args := struct {
			Round     *big.Int
			PublicKey []byte
		}{}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.addDKGMasterPublicKey(args.Round, args.PublicKey)
	case "addDKGMPKReady":
		args := struct {
			Round    *big.Int
			MPKReady []byte
		}{}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.addDKGMPKReady(args.Round, args.MPKReady)
	case "addDKGFinalize":
		args := struct {
			Round    *big.Int
			Finalize []byte
		}{}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.addDKGFinalize(args.Round, args.Finalize)
	case "delegate":
		address := common.Address{}
		if err := method.Inputs.Unpack(&address, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.delegate(address)
	case "delegatorsLength":
		address := common.Address{}
		if err := method.Inputs.Unpack(&address, arguments); err != nil {
			return nil, errExecutionReverted
		}
		res, err := method.Outputs.Pack(g.state.LenDelegators(address))
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "nodesLength":
		res, err := method.Outputs.Pack(g.state.LenNodes())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "payFine":
		address := common.Address{}
		if err := method.Inputs.Unpack(&address, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.payFine(address)
	case "proposeCRS":
		args := struct {
			Round     *big.Int
			SignedCRS []byte
		}{}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.proposeCRS(args.Round, args.SignedCRS)
	case "report":
		args := struct {
			Type *big.Int
			Arg1 []byte
			Arg2 []byte
		}{}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.report(args.Type, args.Arg1, args.Arg2)
	case "stake":
		args := struct {
			PublicKey []byte
			Name      string
			Email     string
			Location  string
			Url       string
		}{}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.stake(args.PublicKey, args.Name, args.Email, args.Location, args.Url)
	case "snapshotRound":
		args := struct {
			Round  *big.Int
			Height *big.Int
		}{}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.snapshotRound(args.Round, args.Height)
	case "transferOwnership":
		var newOwner common.Address
		if err := method.Inputs.Unpack(&newOwner, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.transferOwnership(newOwner)
	case "undelegate":
		address := common.Address{}
		if err := method.Inputs.Unpack(&address, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.undelegate(address)
	case "unstake":
		return g.unstake()
	case "updateConfiguration":
		var cfg rawConfigStruct
		if err := method.Inputs.Unpack(&cfg, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.updateConfiguration(&cfg)
	case "withdraw":
		address := common.Address{}
		if err := method.Inputs.Unpack(&address, arguments); err != nil {
			return nil, errExecutionReverted
		}
		return g.withdraw(address)

	// --------------------------------
	// Solidity auto generated methods.
	// --------------------------------

	case "blockGasLimit":
		res, err := method.Outputs.Pack(g.state.BlockGasLimit())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "crs":
		round := new(big.Int)
		if err := method.Inputs.Unpack(&round, arguments); err != nil {
			return nil, errExecutionReverted
		}
		res, err := method.Outputs.Pack(g.state.CRS(round))
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "delegators":
		nodeAddr, index := common.Address{}, new(big.Int)
		args := []interface{}{&nodeAddr, &index}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		delegator := g.state.Delegator(nodeAddr, index)
		res, err := method.Outputs.Pack(delegator.Owner, delegator.Value, delegator.UndelegatedAt)
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "delegatorsOffset":
		nodeAddr, delegatorAddr := common.Address{}, common.Address{}
		args := []interface{}{&nodeAddr, &delegatorAddr}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		res, err := method.Outputs.Pack(g.state.DelegatorsOffset(nodeAddr, delegatorAddr))
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "dkgComplaints":
		round, index := new(big.Int), new(big.Int)
		args := []interface{}{&round, &index}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		complaints := g.state.DKGComplaints(round)
		if int(index.Uint64()) >= len(complaints) {
			return nil, errExecutionReverted
		}
		complaint := complaints[index.Uint64()]
		res, err := method.Outputs.Pack(complaint)
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "dkgReadys":
		round, addr := new(big.Int), common.Address{}
		args := []interface{}{&round, &addr}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		ready := g.state.DKGMPKReady(round, addr)
		res, err := method.Outputs.Pack(ready)
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "dkgReadysCount":
		round := new(big.Int)
		if err := method.Inputs.Unpack(&round, arguments); err != nil {
			return nil, errExecutionReverted
		}
		count := g.state.DKGMPKReadysCount(round)
		res, err := method.Outputs.Pack(count)
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil

	case "dkgFinalizeds":
		round, addr := new(big.Int), common.Address{}
		args := []interface{}{&round, &addr}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		finalized := g.state.DKGFinalized(round, addr)
		res, err := method.Outputs.Pack(finalized)
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "dkgFinalizedsCount":
		round := new(big.Int)
		if err := method.Inputs.Unpack(&round, arguments); err != nil {
			return nil, errExecutionReverted
		}
		count := g.state.DKGFinalizedsCount(round)
		res, err := method.Outputs.Pack(count)
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "dkgMasterPublicKeys":
		round, index := new(big.Int), new(big.Int)
		args := []interface{}{&round, &index}
		if err := method.Inputs.Unpack(&args, arguments); err != nil {
			return nil, errExecutionReverted
		}
		mpks := g.state.DKGMasterPublicKeys(round)
		if int(index.Uint64()) >= len(mpks) {
			return nil, errExecutionReverted
		}
		mpk := mpks[index.Uint64()]
		res, err := method.Outputs.Pack(mpk)
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "dkgSetSize":
		res, err := method.Outputs.Pack(g.state.DKGSetSize())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "finedRecords":
		record := Bytes32{}
		if err := method.Inputs.Unpack(&record, arguments); err != nil {
			return nil, errExecutionReverted
		}
		value := g.state.FineRecords(record)
		res, err := method.Outputs.Pack(value)
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "fineValues":
		index := new(big.Int)
		if err := method.Inputs.Unpack(&index, arguments); err != nil {
			return nil, errExecutionReverted
		}
		value := g.state.FineValue(index)
		res, err := method.Outputs.Pack(value)
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "k":
		res, err := method.Outputs.Pack(g.state.K())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "lambdaBA":
		res, err := method.Outputs.Pack(g.state.LambdaBA())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "lambdaDKG":
		res, err := method.Outputs.Pack(g.state.LambdaDKG())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "lastHalvedAmount":
		res, err := method.Outputs.Pack(g.state.LastHalvedAmount())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "lockupPeriod":
		res, err := method.Outputs.Pack(g.state.LockupPeriod())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "minBlockInterval":
		res, err := method.Outputs.Pack(g.state.MinBlockInterval())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "miningVelocity":
		res, err := method.Outputs.Pack(g.state.MiningVelocity())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "minStake":
		res, err := method.Outputs.Pack(g.state.MinStake())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "nextHalvingSupply":
		res, err := method.Outputs.Pack(g.state.NextHalvingSupply())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "numChains":
		res, err := method.Outputs.Pack(g.state.NumChains())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "nodes":
		index := new(big.Int)
		if err := method.Inputs.Unpack(&index, arguments); err != nil {
			return nil, errExecutionReverted
		}
		info := g.state.Node(index)
		res, err := method.Outputs.Pack(
			info.Owner, info.PublicKey, info.Staked, info.Fined,
			info.Name, info.Email, info.Location, info.Url)
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "nodesOffsetByAddress":
		address := common.Address{}
		if err := method.Inputs.Unpack(&address, arguments); err != nil {
			return nil, errExecutionReverted
		}
		res, err := method.Outputs.Pack(g.state.NodesOffsetByAddress(address))
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "nodesOffsetByID":
		var id Bytes32
		if err := method.Inputs.Unpack(&id, arguments); err != nil {
			return nil, errExecutionReverted
		}
		res, err := method.Outputs.Pack(g.state.NodesOffsetByID(id))
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "notarySetSize":
		res, err := method.Outputs.Pack(g.state.NotarySetSize())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "owner":
		res, err := method.Outputs.Pack(g.state.Owner())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "phiRatio":
		res, err := method.Outputs.Pack(g.state.PhiRatio())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "roundHeight":
		round := new(big.Int)
		if err := method.Inputs.Unpack(&round, arguments); err != nil {
			return nil, errExecutionReverted
		}
		res, err := method.Outputs.Pack(g.state.RoundHeight(round))
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "roundInterval":
		res, err := method.Outputs.Pack(g.state.RoundInterval())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "totalStaked":
		res, err := method.Outputs.Pack(g.state.TotalStaked())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	case "totalSupply":
		res, err := method.Outputs.Pack(g.state.TotalSupply())
		if err != nil {
			return nil, errExecutionReverted
		}
		return res, nil
	}
	return nil, errExecutionReverted
}

// Storage position enums.
const (
	roundHeightLoc = iota
	totalSupplyLoc
	totalStakedLoc
	nodesLoc
	nodesOffsetByAddressLoc
	nodesOffsetByIDLoc
	delegatorsLoc
	delegatorsOffsetLoc
	crsLoc
	dkgMasterPublicKeysLoc
	dkgComplaintsLoc
	dkgReadyLoc
	dkgReadysCountLoc
	dkgFinalizedLoc
	dkgFinalizedsCountLoc
	ownerLoc
	minStakeLoc
	lockupPeriodLoc
	miningVelocityLoc
	nextHalvingSupplyLoc
	lastHalvedAmountLoc
	blockGasLimitLoc
	numChainsLoc
	lambdaBALoc
	lambdaDKGLoc
	kLoc
	phiRatioLoc
	notarySetSizeLoc
	dkgSetSizeLoc
	roundIntervalLoc
	minBlockIntervalLoc
	fineValuesLoc
	finedRecordsLoc
)

func publicKeyToNodeID(pkBytes []byte) (Bytes32, error) {
	pk, err := crypto.UnmarshalPubkey(pkBytes)
	if err != nil {
		return Bytes32{}, err
	}
	id := Bytes32(coreTypes.NewNodeID(ecdsa.NewPublicKeyFromECDSA(pk)).Hash)
	return id, nil
}

// State manipulation helper fro the governance contract.
type GovernanceStateHelper struct {
	StateDB StateDB
}

func (s *GovernanceStateHelper) getState(loc common.Hash) common.Hash {
	return s.StateDB.GetState(GovernanceContractAddress, loc)
}

func (s *GovernanceStateHelper) setState(loc common.Hash, val common.Hash) {
	s.StateDB.SetState(GovernanceContractAddress, loc, val)
}

func (s *GovernanceStateHelper) getStateBigInt(loc *big.Int) *big.Int {
	res := s.StateDB.GetState(GovernanceContractAddress, common.BigToHash(loc))
	return new(big.Int).SetBytes(res.Bytes())
}

func (s *GovernanceStateHelper) setStateBigInt(loc *big.Int, val *big.Int) {
	s.setState(common.BigToHash(loc), common.BigToHash(val))
}

func (s *GovernanceStateHelper) getSlotLoc(loc *big.Int) *big.Int {
	return new(big.Int).SetBytes(crypto.Keccak256(common.BigToHash(loc).Bytes()))
}

func (s *GovernanceStateHelper) getMapLoc(pos *big.Int, key []byte) *big.Int {
	return new(big.Int).SetBytes(crypto.Keccak256(key, common.BigToHash(pos).Bytes()))
}

func (s *GovernanceStateHelper) readBytes(loc *big.Int) []byte {
	// Length of the dynamic array (bytes).
	rawLength := s.getStateBigInt(loc)
	lengthByte := new(big.Int).Mod(rawLength, big.NewInt(256))

	// Bytes length <= 31, lengthByte % 2 == 0
	// return the high 31 bytes.
	if new(big.Int).Mod(lengthByte, big.NewInt(2)).Cmp(big.NewInt(0)) == 0 {
		length := new(big.Int).Div(lengthByte, big.NewInt(2)).Uint64()
		return rawLength.Bytes()[:length]
	}

	// Actual length = (rawLength - 1) / 2
	length := new(big.Int).Div(new(big.Int).Sub(rawLength, big.NewInt(1)), big.NewInt(2)).Uint64()

	// Data address.
	dataLoc := s.getSlotLoc(loc)

	// Read continuously for length bytes.
	carry := int64(0)
	if length%32 > 0 {
		carry = 1
	}
	chunks := int64(length/32) + carry
	var data []byte
	for i := int64(0); i < chunks; i++ {
		loc = new(big.Int).Add(dataLoc, big.NewInt(i))
		data = append(data, s.getState(common.BigToHash(loc)).Bytes()...)
	}
	data = data[:length]
	return data
}

func (s *GovernanceStateHelper) writeBytes(loc *big.Int, data []byte) {
	length := int64(len(data))

	if length == 0 {
		s.setState(common.BigToHash(loc), common.Hash{})
		return
	}

	// Short bytes (length <= 31).
	if length < 32 {
		data2 := append([]byte(nil), data...)
		// Right pad with zeros
		for len(data2) < 31 {
			data2 = append(data2, byte(0))
		}
		data2 = append(data2, byte(length*2))
		s.setState(common.BigToHash(loc), common.BytesToHash(data2))
		return
	}

	// Write 2 * length + 1.
	storedLength := new(big.Int).Add(new(big.Int).Mul(
		big.NewInt(length), big.NewInt(2)), big.NewInt(1))
	s.setStateBigInt(loc, storedLength)
	// Write data chunck.
	dataLoc := s.getSlotLoc(loc)
	carry := int64(0)
	if length%32 > 0 {
		carry = 1
	}
	chunks := length/32 + carry
	for i := int64(0); i < chunks; i++ {
		loc = new(big.Int).Add(dataLoc, big.NewInt(i))
		maxLoc := (i + 1) * 32
		if maxLoc > length {
			maxLoc = length
		}
		data2 := data[i*32 : maxLoc]
		// Right pad with zeros.
		for len(data2) < 32 {
			data2 = append(data2, byte(0))
		}
		s.setState(common.BigToHash(loc), common.BytesToHash(data2))
	}
}

func (s *GovernanceStateHelper) read2DByteArray(pos, index *big.Int) [][]byte {
	baseLoc := s.getSlotLoc(pos)
	loc := new(big.Int).Add(baseLoc, index)

	arrayLength := s.getStateBigInt(loc)
	dataLoc := s.getSlotLoc(loc)

	data := [][]byte{}
	for i := int64(0); i < int64(arrayLength.Uint64()); i++ {
		elementLoc := new(big.Int).Add(dataLoc, big.NewInt(i))
		data = append(data, s.readBytes(elementLoc))
	}

	return data
}
func (s *GovernanceStateHelper) appendTo2DByteArray(pos, index *big.Int, data []byte) {
	// Find the loc of the last element.
	baseLoc := s.getSlotLoc(pos)
	loc := new(big.Int).Add(baseLoc, index)

	// Increase length by 1.
	arrayLength := s.getStateBigInt(loc)
	s.setStateBigInt(loc, new(big.Int).Add(arrayLength, big.NewInt(1)))

	// Write element.
	dataLoc := s.getSlotLoc(loc)
	elementLoc := new(big.Int).Add(dataLoc, arrayLength)
	s.writeBytes(elementLoc, data)
}

// uint256[] public roundHeight;
func (s *GovernanceStateHelper) LenRoundHeight() *big.Int {
	return s.getStateBigInt(big.NewInt(roundHeightLoc))
}
func (s *GovernanceStateHelper) RoundHeight(round *big.Int) *big.Int {
	baseLoc := s.getSlotLoc(big.NewInt(roundHeightLoc))
	loc := new(big.Int).Add(baseLoc, round)
	return s.getStateBigInt(loc)
}
func (s *GovernanceStateHelper) PushRoundHeight(height *big.Int) {
	// Increase length by 1.
	length := s.getStateBigInt(big.NewInt(roundHeightLoc))
	s.setStateBigInt(big.NewInt(roundHeightLoc), new(big.Int).Add(length, big.NewInt(1)))

	baseLoc := s.getSlotLoc(big.NewInt(roundHeightLoc))
	loc := new(big.Int).Add(baseLoc, length)

	s.setStateBigInt(loc, height)
}

// uint256 public totalSupply;
func (s *GovernanceStateHelper) TotalSupply() *big.Int {
	return s.getStateBigInt(big.NewInt(totalSupplyLoc))
}
func (s *GovernanceStateHelper) IncTotalSupply(amount *big.Int) {
	s.setStateBigInt(big.NewInt(totalSupplyLoc), new(big.Int).Add(s.TotalSupply(), amount))
}
func (s *GovernanceStateHelper) DecTotalSupply(amount *big.Int) {
	s.setStateBigInt(big.NewInt(totalSupplyLoc), new(big.Int).Sub(s.TotalSupply(), amount))
}

// uint256 public totalStaked;
func (s *GovernanceStateHelper) TotalStaked() *big.Int {
	return s.getStateBigInt(big.NewInt(totalStakedLoc))
}
func (s *GovernanceStateHelper) IncTotalStaked(amount *big.Int) {
	s.setStateBigInt(big.NewInt(totalStakedLoc), new(big.Int).Add(s.TotalStaked(), amount))
}
func (s *GovernanceStateHelper) DecTotalStaked(amount *big.Int) {
	s.setStateBigInt(big.NewInt(totalStakedLoc), new(big.Int).Sub(s.TotalStaked(), amount))
}

// struct Node {
//     address owner;
//     bytes publicKey;
//     uint256 staked;
//     uint256 fined;
//     string name;
//     string email;
//     string location;
//     string url;
// }
//
// Node[] nodes;

type nodeInfo struct {
	Owner     common.Address
	PublicKey []byte
	Staked    *big.Int
	Fined     *big.Int
	Name      string
	Email     string
	Location  string
	Url       string
}

const nodeStructSize = 8

func (s *GovernanceStateHelper) LenNodes() *big.Int {
	return s.getStateBigInt(big.NewInt(nodesLoc))
}
func (s *GovernanceStateHelper) Node(index *big.Int) *nodeInfo {
	node := new(nodeInfo)

	arrayBaseLoc := s.getSlotLoc(big.NewInt(nodesLoc))
	elementBaseLoc := new(big.Int).Add(arrayBaseLoc,
		new(big.Int).Mul(index, big.NewInt(nodeStructSize)))

	// Owner.
	loc := elementBaseLoc
	node.Owner = common.BytesToAddress(s.getState(common.BigToHash(elementBaseLoc)).Bytes())

	// PublicKey.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(1))
	node.PublicKey = s.readBytes(loc)

	// Staked.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(2))
	node.Staked = s.getStateBigInt(loc)

	// Fined.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(3))
	node.Fined = s.getStateBigInt(loc)

	// Name.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(4))
	node.Name = string(s.readBytes(loc))

	// Email.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(5))
	node.Email = string(s.readBytes(loc))

	// Location.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(6))
	node.Location = string(s.readBytes(loc))

	// Url.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(7))
	node.Url = string(s.readBytes(loc))

	return node
}
func (s *GovernanceStateHelper) PushNode(n *nodeInfo) {
	// Increase length by 1.
	arrayLength := s.LenNodes()
	s.setStateBigInt(big.NewInt(nodesLoc), new(big.Int).Add(arrayLength, big.NewInt(1)))

	s.UpdateNode(arrayLength, n)
}
func (s *GovernanceStateHelper) UpdateNode(index *big.Int, n *nodeInfo) {
	arrayBaseLoc := s.getSlotLoc(big.NewInt(nodesLoc))
	elementBaseLoc := new(big.Int).Add(arrayBaseLoc,
		new(big.Int).Mul(index, big.NewInt(nodeStructSize)))

	// Owner.
	loc := elementBaseLoc
	s.setState(common.BigToHash(loc), n.Owner.Hash())

	// PublicKey.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(1))
	s.writeBytes(loc, n.PublicKey)

	// Staked.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(2))
	s.setStateBigInt(loc, n.Staked)

	// Fined.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(3))
	s.setStateBigInt(loc, n.Fined)

	// Name.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(4))
	s.writeBytes(loc, []byte(n.Name))

	// Email.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(5))
	s.writeBytes(loc, []byte(n.Email))

	// Location.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(6))
	s.writeBytes(loc, []byte(n.Location))

	// Url.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(7))
	s.writeBytes(loc, []byte(n.Url))
}
func (s *GovernanceStateHelper) PopLastNode() {
	// Decrease length by 1.
	arrayLength := s.LenNodes()
	newArrayLength := new(big.Int).Sub(arrayLength, big.NewInt(1))
	s.setStateBigInt(big.NewInt(nodesLoc), newArrayLength)

	s.UpdateNode(newArrayLength, &nodeInfo{
		Staked: big.NewInt(0),
		Fined:  big.NewInt(0),
	})
}
func (s *GovernanceStateHelper) Nodes() []*nodeInfo {
	var nodes []*nodeInfo
	for i := int64(0); i < int64(s.LenNodes().Uint64()); i++ {
		nodes = append(nodes, s.Node(big.NewInt(i)))
	}
	return nodes
}
func (s *GovernanceStateHelper) QualifiedNodes() []*nodeInfo {
	var nodes []*nodeInfo
	for i := int64(0); i < int64(s.LenNodes().Uint64()); i++ {
		node := s.Node(big.NewInt(i))
		if new(big.Int).Sub(node.Staked, node.Fined).Cmp(s.MinStake()) >= 0 {
			nodes = append(nodes, node)
		}
	}
	return nodes
}

// mapping(address => uint256) public nodeOffsetByAddress;
func (s *GovernanceStateHelper) NodesOffsetByAddress(addr common.Address) *big.Int {
	loc := s.getMapLoc(big.NewInt(nodesOffsetByAddressLoc), addr.Bytes())
	return new(big.Int).Sub(s.getStateBigInt(loc), big.NewInt(1))
}
func (s *GovernanceStateHelper) PutNodesOffsetByAddress(addr common.Address, offset *big.Int) {
	loc := s.getMapLoc(big.NewInt(nodesOffsetByAddressLoc), addr.Bytes())
	s.setStateBigInt(loc, new(big.Int).Add(offset, big.NewInt(1)))
}
func (s *GovernanceStateHelper) DeleteNodesOffsetByAddress(addr common.Address) {
	loc := s.getMapLoc(big.NewInt(nodesOffsetByAddressLoc), addr.Bytes())
	s.setStateBigInt(loc, big.NewInt(0))
}

// mapping(address => uint256) public nodeOffsetByID;
func (s *GovernanceStateHelper) NodesOffsetByID(id Bytes32) *big.Int {
	loc := s.getMapLoc(big.NewInt(nodesOffsetByIDLoc), id[:])
	return new(big.Int).Sub(s.getStateBigInt(loc), big.NewInt(1))
}
func (s *GovernanceStateHelper) PutNodesOffsetByID(id Bytes32, offset *big.Int) {
	loc := s.getMapLoc(big.NewInt(nodesOffsetByIDLoc), id[:])
	s.setStateBigInt(loc, new(big.Int).Add(offset, big.NewInt(1)))
}
func (s *GovernanceStateHelper) DeleteNodesOffsetByID(id Bytes32) {
	loc := s.getMapLoc(big.NewInt(nodesOffsetByIDLoc), id[:])
	s.setStateBigInt(loc, big.NewInt(0))
}

func (s *GovernanceStateHelper) PutNodeOffsets(n *nodeInfo, offset *big.Int) error {
	id, err := publicKeyToNodeID(n.PublicKey)
	if err != nil {
		return err
	}
	s.PutNodesOffsetByID(id, offset)
	s.PutNodesOffsetByAddress(n.Owner, offset)
	return nil
}

// struct Delegator {
//     address node;
//     address owner;
//     uint256 value;
//     uint256 undelegated_at;
// }

type delegatorInfo struct {
	Owner         common.Address
	Value         *big.Int
	UndelegatedAt *big.Int
}

const delegatorStructSize = 3

// mapping(address => Delegator[]) public delegators;
func (s *GovernanceStateHelper) LenDelegators(nodeAddr common.Address) *big.Int {
	loc := s.getMapLoc(big.NewInt(delegatorsLoc), nodeAddr.Bytes())
	return s.getStateBigInt(loc)
}
func (s *GovernanceStateHelper) Delegator(nodeAddr common.Address, offset *big.Int) *delegatorInfo {
	delegator := new(delegatorInfo)

	loc := s.getMapLoc(big.NewInt(delegatorsLoc), nodeAddr.Bytes())
	arrayBaseLoc := s.getSlotLoc(loc)
	elementBaseLoc := new(big.Int).Add(arrayBaseLoc, new(big.Int).Mul(big.NewInt(delegatorStructSize), offset))

	// Owner.
	loc = elementBaseLoc
	delegator.Owner = common.BytesToAddress(s.getState(common.BigToHash(elementBaseLoc)).Bytes())

	// Value.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(1))
	delegator.Value = s.getStateBigInt(loc)

	// UndelegatedAt.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(2))
	delegator.UndelegatedAt = s.getStateBigInt(loc)

	return delegator
}
func (s *GovernanceStateHelper) PushDelegator(nodeAddr common.Address, delegator *delegatorInfo) {
	// Increase length by 1.
	arrayLength := s.LenDelegators(nodeAddr)
	loc := s.getMapLoc(big.NewInt(delegatorsLoc), nodeAddr.Bytes())
	s.setStateBigInt(loc, new(big.Int).Add(arrayLength, big.NewInt(1)))

	s.UpdateDelegator(nodeAddr, arrayLength, delegator)
}
func (s *GovernanceStateHelper) UpdateDelegator(nodeAddr common.Address, offset *big.Int, delegator *delegatorInfo) {
	loc := s.getMapLoc(big.NewInt(delegatorsLoc), nodeAddr.Bytes())
	arrayBaseLoc := s.getSlotLoc(loc)
	elementBaseLoc := new(big.Int).Add(arrayBaseLoc, new(big.Int).Mul(big.NewInt(delegatorStructSize), offset))

	// Owner.
	loc = elementBaseLoc
	s.setState(common.BigToHash(loc), delegator.Owner.Hash())

	// Value.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(1))
	s.setStateBigInt(loc, delegator.Value)

	// UndelegatedAt.
	loc = new(big.Int).Add(elementBaseLoc, big.NewInt(2))
	s.setStateBigInt(loc, delegator.UndelegatedAt)
}
func (s *GovernanceStateHelper) PopLastDelegator(nodeAddr common.Address) {
	// Decrease length by 1.
	arrayLength := s.LenDelegators(nodeAddr)
	newArrayLength := new(big.Int).Sub(arrayLength, big.NewInt(1))
	loc := s.getMapLoc(big.NewInt(delegatorsLoc), nodeAddr.Bytes())
	s.setStateBigInt(loc, newArrayLength)

	s.UpdateDelegator(nodeAddr, newArrayLength, &delegatorInfo{
		Value:         big.NewInt(0),
		UndelegatedAt: big.NewInt(0),
	})
}

// mapping(address => mapping(address => uint256)) delegatorsOffset;
func (s *GovernanceStateHelper) DelegatorsOffset(nodeAddr, delegatorAddr common.Address) *big.Int {
	loc := s.getMapLoc(s.getMapLoc(big.NewInt(delegatorsOffsetLoc), nodeAddr.Bytes()), delegatorAddr.Bytes())
	return new(big.Int).Sub(s.getStateBigInt(loc), big.NewInt(1))
}
func (s *GovernanceStateHelper) PutDelegatorOffset(nodeAddr, delegatorAddr common.Address, offset *big.Int) {
	loc := s.getMapLoc(s.getMapLoc(big.NewInt(delegatorsOffsetLoc), nodeAddr.Bytes()), delegatorAddr.Bytes())
	s.setStateBigInt(loc, new(big.Int).Add(offset, big.NewInt(1)))
}
func (s *GovernanceStateHelper) DeleteDelegatorsOffset(nodeAddr, delegatorAddr common.Address) {
	loc := s.getMapLoc(s.getMapLoc(big.NewInt(delegatorsOffsetLoc), nodeAddr.Bytes()), delegatorAddr.Bytes())
	s.setStateBigInt(loc, big.NewInt(0))
}

// bytes32[] public crs;
func (s *GovernanceStateHelper) LenCRS() *big.Int {
	return s.getStateBigInt(big.NewInt(crsLoc))
}
func (s *GovernanceStateHelper) CRS(index *big.Int) common.Hash {
	baseLoc := s.getSlotLoc(big.NewInt(crsLoc))
	loc := new(big.Int).Add(baseLoc, index)
	return s.getState(common.BigToHash(loc))
}
func (s *GovernanceStateHelper) CurrentCRS() common.Hash {
	return s.CRS(new(big.Int).Sub(s.LenCRS(), big.NewInt(1)))
}
func (s *GovernanceStateHelper) PushCRS(crs common.Hash) {
	// increase length by 1.
	length := s.getStateBigInt(big.NewInt(crsLoc))
	s.setStateBigInt(big.NewInt(crsLoc), new(big.Int).Add(length, big.NewInt(1)))

	baseLoc := s.getSlotLoc(big.NewInt(crsLoc))
	loc := new(big.Int).Add(baseLoc, length)

	s.setState(common.BigToHash(loc), crs)
}
func (s *GovernanceStateHelper) Round() *big.Int {
	return new(big.Int).Sub(s.getStateBigInt(big.NewInt(crsLoc)), big.NewInt(1))
}

// bytes[][] public dkgMasterPublicKeys;
func (s *GovernanceStateHelper) DKGMasterPublicKeys(round *big.Int) [][]byte {
	return s.read2DByteArray(big.NewInt(dkgMasterPublicKeysLoc), round)
}
func (s *GovernanceStateHelper) PushDKGMasterPublicKey(round *big.Int, mpk []byte) {
	s.appendTo2DByteArray(big.NewInt(dkgMasterPublicKeysLoc), round, mpk)
}
func (s *GovernanceStateHelper) UniqueDKGMasterPublicKeys(round *big.Int) []*dkgTypes.MasterPublicKey {
	// Prepare DKGMasterPublicKeys.
	var dkgMasterPKs []*dkgTypes.MasterPublicKey
	existence := make(map[coreTypes.NodeID]struct{})
	for _, mpk := range s.DKGMasterPublicKeys(round) {
		x := new(dkgTypes.MasterPublicKey)
		if err := rlp.DecodeBytes(mpk, x); err != nil {
			panic(err)
		}

		// Only the first DKG MPK submission is valid.
		if _, exists := existence[x.ProposerID]; exists {
			continue
		}
		existence[x.ProposerID] = struct{}{}
		dkgMasterPKs = append(dkgMasterPKs, x)
	}
	return dkgMasterPKs
}
func (s *GovernanceStateHelper) GetDKGMasterPublicKeyByProposerID(
	round *big.Int, proposerID coreTypes.NodeID) (*dkgTypes.MasterPublicKey, error) {

	for _, mpk := range s.DKGMasterPublicKeys(round) {
		x := new(dkgTypes.MasterPublicKey)
		if err := rlp.DecodeBytes(mpk, x); err != nil {
			panic(err)
		}
		if x.ProposerID.Equal(proposerID) {
			return x, nil
		}
	}
	return nil, errors.New("not found")
}

// bytes[][] public dkgComplaints;
func (s *GovernanceStateHelper) DKGComplaints(round *big.Int) [][]byte {
	return s.read2DByteArray(big.NewInt(dkgComplaintsLoc), round)
}
func (s *GovernanceStateHelper) PushDKGComplaint(round *big.Int, complaint []byte) {
	s.appendTo2DByteArray(big.NewInt(dkgComplaintsLoc), round, complaint)
}

// mapping(address => bool)[] public dkgReady;
func (s *GovernanceStateHelper) DKGMPKReady(round *big.Int, addr common.Address) bool {
	baseLoc := new(big.Int).Add(s.getSlotLoc(big.NewInt(dkgReadyLoc)), round)
	mapLoc := s.getMapLoc(baseLoc, addr.Bytes())
	return s.getStateBigInt(mapLoc).Cmp(big.NewInt(0)) != 0
}
func (s *GovernanceStateHelper) PutDKGMPKReady(round *big.Int, addr common.Address, ready bool) {
	baseLoc := new(big.Int).Add(s.getSlotLoc(big.NewInt(dkgReadyLoc)), round)
	mapLoc := s.getMapLoc(baseLoc, addr.Bytes())
	res := big.NewInt(0)
	if ready {
		res = big.NewInt(1)
	}
	s.setStateBigInt(mapLoc, res)
}

// uint256[] public dkgReadysCount;
func (s *GovernanceStateHelper) DKGMPKReadysCount(round *big.Int) *big.Int {
	loc := new(big.Int).Add(s.getSlotLoc(big.NewInt(dkgReadysCountLoc)), round)
	return s.getStateBigInt(loc)
}
func (s *GovernanceStateHelper) IncDKGMPKReadysCount(round *big.Int) {
	loc := new(big.Int).Add(s.getSlotLoc(big.NewInt(dkgReadysCountLoc)), round)
	count := s.getStateBigInt(loc)
	s.setStateBigInt(loc, new(big.Int).Add(count, big.NewInt(1)))
}

// mapping(address => bool)[] public dkgFinalized;
func (s *GovernanceStateHelper) DKGFinalized(round *big.Int, addr common.Address) bool {
	baseLoc := new(big.Int).Add(s.getSlotLoc(big.NewInt(dkgFinalizedLoc)), round)
	mapLoc := s.getMapLoc(baseLoc, addr.Bytes())
	return s.getStateBigInt(mapLoc).Cmp(big.NewInt(0)) != 0
}
func (s *GovernanceStateHelper) PutDKGFinalized(round *big.Int, addr common.Address, finalized bool) {
	baseLoc := new(big.Int).Add(s.getSlotLoc(big.NewInt(dkgFinalizedLoc)), round)
	mapLoc := s.getMapLoc(baseLoc, addr.Bytes())
	res := big.NewInt(0)
	if finalized {
		res = big.NewInt(1)
	}
	s.setStateBigInt(mapLoc, res)
}

// uint256[] public dkgFinalizedsCount;
func (s *GovernanceStateHelper) DKGFinalizedsCount(round *big.Int) *big.Int {
	loc := new(big.Int).Add(s.getSlotLoc(big.NewInt(dkgFinalizedsCountLoc)), round)
	return s.getStateBigInt(loc)
}
func (s *GovernanceStateHelper) IncDKGFinalizedsCount(round *big.Int) {
	loc := new(big.Int).Add(s.getSlotLoc(big.NewInt(dkgFinalizedsCountLoc)), round)
	count := s.getStateBigInt(loc)
	s.setStateBigInt(loc, new(big.Int).Add(count, big.NewInt(1)))
}

// address public owner;
func (s *GovernanceStateHelper) Owner() common.Address {
	val := s.getState(common.BigToHash(big.NewInt(ownerLoc)))
	return common.BytesToAddress(val.Bytes())
}
func (s *GovernanceStateHelper) SetOwner(newOwner common.Address) {
	s.setState(common.BigToHash(big.NewInt(ownerLoc)), newOwner.Hash())
}

// uint256 public minStake;
func (s *GovernanceStateHelper) MinStake() *big.Int {
	return s.getStateBigInt(big.NewInt(minStakeLoc))
}

// uint256 public lockupPeriod;
func (s *GovernanceStateHelper) LockupPeriod() *big.Int {
	return s.getStateBigInt(big.NewInt(lockupPeriodLoc))
}

// uint256 public miningVelocity;
func (s *GovernanceStateHelper) MiningVelocity() *big.Int {
	return s.getStateBigInt(big.NewInt(miningVelocityLoc))
}
func (s *GovernanceStateHelper) HalfMiningVelocity() {
	s.setStateBigInt(big.NewInt(miningVelocityLoc),
		new(big.Int).Div(s.MiningVelocity(), big.NewInt(2)))
}

// uint256 public nextHalvingSupply;
func (s *GovernanceStateHelper) NextHalvingSupply() *big.Int {
	return s.getStateBigInt(big.NewInt(nextHalvingSupplyLoc))
}
func (s *GovernanceStateHelper) IncNextHalvingSupply(amount *big.Int) {
	s.setStateBigInt(big.NewInt(nextHalvingSupplyLoc),
		new(big.Int).Add(s.NextHalvingSupply(), amount))
}

// uint256 public lastHalvedAmount;
func (s *GovernanceStateHelper) LastHalvedAmount() *big.Int {
	return s.getStateBigInt(big.NewInt(lastHalvedAmountLoc))
}
func (s *GovernanceStateHelper) HalfLastHalvedAmount() {
	s.setStateBigInt(big.NewInt(lastHalvedAmountLoc),
		new(big.Int).Div(s.LastHalvedAmount(), big.NewInt(2)))
}

func (s *GovernanceStateHelper) MiningHalved() {
	s.HalfMiningVelocity()
	s.HalfLastHalvedAmount()
	s.IncNextHalvingSupply(s.LastHalvedAmount())
}

// uint256 public blockGasLimit;
func (s *GovernanceStateHelper) BlockGasLimit() *big.Int {
	return s.getStateBigInt(big.NewInt(blockGasLimitLoc))
}
func (s *GovernanceStateHelper) SetBlockGasLimit(reward *big.Int) {
	s.setStateBigInt(big.NewInt(blockGasLimitLoc), reward)
}

// uint256 public numChains;
func (s *GovernanceStateHelper) NumChains() *big.Int {
	return s.getStateBigInt(big.NewInt(numChainsLoc))
}

// uint256 public lambdaBA;
func (s *GovernanceStateHelper) LambdaBA() *big.Int {
	return s.getStateBigInt(big.NewInt(lambdaBALoc))
}

// uint256 public lambdaDKG;
func (s *GovernanceStateHelper) LambdaDKG() *big.Int {
	return s.getStateBigInt(big.NewInt(lambdaDKGLoc))
}

// uint256 public k;
func (s *GovernanceStateHelper) K() *big.Int {
	return s.getStateBigInt(big.NewInt(kLoc))
}

// uint256 public phiRatio;  // stored as PhiRatio * 10^6
func (s *GovernanceStateHelper) PhiRatio() *big.Int {
	return s.getStateBigInt(big.NewInt(phiRatioLoc))
}

// uint256 public notarySetSize;
func (s *GovernanceStateHelper) NotarySetSize() *big.Int {
	return s.getStateBigInt(big.NewInt(notarySetSizeLoc))
}

// uint256 public dkgSetSize;
func (s *GovernanceStateHelper) DKGSetSize() *big.Int {
	return s.getStateBigInt(big.NewInt(dkgSetSizeLoc))
}

// uint256 public roundInterval;
func (s *GovernanceStateHelper) RoundInterval() *big.Int {
	return s.getStateBigInt(big.NewInt(roundIntervalLoc))
}

// uint256 public minBlockInterval;
func (s *GovernanceStateHelper) MinBlockInterval() *big.Int {
	return s.getStateBigInt(big.NewInt(minBlockIntervalLoc))
}

// uint256[] public fineValues;
func (s *GovernanceStateHelper) FineValue(index *big.Int) *big.Int {
	arrayBaseLoc := s.getSlotLoc(big.NewInt(fineValuesLoc))
	return s.getStateBigInt(new(big.Int).Add(arrayBaseLoc, index))
}
func (s *GovernanceStateHelper) FineValues() []*big.Int {
	len := s.getStateBigInt(big.NewInt(fineValuesLoc))
	result := make([]*big.Int, len.Uint64())
	for i := 0; i < int(len.Uint64()); i++ {
		result[i] = s.FineValue(big.NewInt(int64(i)))
	}
	return result
}
func (s *GovernanceStateHelper) SetFineValues(values []*big.Int) {
	s.setStateBigInt(big.NewInt(fineValuesLoc), big.NewInt(int64(len(values))))

	arrayBaseLoc := s.getSlotLoc(big.NewInt(fineValuesLoc))
	for i, v := range values {
		s.setStateBigInt(new(big.Int).Add(arrayBaseLoc, big.NewInt(int64(i))), v)
	}
}

// uint256[] public fineRdecords;
func (s *GovernanceStateHelper) FineRecords(recordHash Bytes32) bool {
	loc := s.getMapLoc(big.NewInt(finedRecordsLoc), recordHash[:])
	return s.getStateBigInt(loc).Cmp(big.NewInt(0)) > 0
}
func (s *GovernanceStateHelper) SetFineRecords(recordHash Bytes32, status bool) {
	loc := s.getMapLoc(big.NewInt(finedRecordsLoc), recordHash[:])
	value := int64(0)
	if status {
		value = int64(1)
	}
	s.setStateBigInt(loc, big.NewInt(value))
}

// Stake is a helper function for creating genesis state.
func (s *GovernanceStateHelper) Stake(
	addr common.Address, publicKey []byte, staked *big.Int,
	name, email, location, url string) {
	offset := s.LenNodes()
	node := &nodeInfo{
		Owner:     addr,
		PublicKey: publicKey,
		Staked:    staked,
		Fined:     big.NewInt(0),
		Name:      name,
		Email:     email,
		Location:  location,
		Url:       url,
	}
	s.PushNode(node)
	if err := s.PutNodeOffsets(node, offset); err != nil {
		panic(err)
	}

	if staked.Cmp(big.NewInt(0)) == 0 {
		return
	}

	offset = s.LenDelegators(addr)
	s.PushDelegator(addr, &delegatorInfo{
		Owner:         addr,
		Value:         staked,
		UndelegatedAt: big.NewInt(0),
	})
	s.PutDelegatorOffset(addr, addr, offset)

	// Add to network total staked.
	s.IncTotalStaked(staked)
}

const decimalMultiplier = 100000000.0

// Configuration returns the current configuration.
func (s *GovernanceStateHelper) Configuration() *params.DexconConfig {
	return &params.DexconConfig{
		MinStake:          s.getStateBigInt(big.NewInt(minStakeLoc)),
		LockupPeriod:      s.getStateBigInt(big.NewInt(lockupPeriodLoc)).Uint64(),
		MiningVelocity:    float32(s.getStateBigInt(big.NewInt(miningVelocityLoc)).Uint64()) / decimalMultiplier,
		NextHalvingSupply: s.getStateBigInt(big.NewInt(nextHalvingSupplyLoc)),
		LastHalvedAmount:  s.getStateBigInt(big.NewInt(lastHalvedAmountLoc)),
		BlockGasLimit:     s.getStateBigInt(big.NewInt(blockGasLimitLoc)).Uint64(),
		NumChains:         uint32(s.getStateBigInt(big.NewInt(numChainsLoc)).Uint64()),
		LambdaBA:          s.getStateBigInt(big.NewInt(lambdaBALoc)).Uint64(),
		LambdaDKG:         s.getStateBigInt(big.NewInt(lambdaDKGLoc)).Uint64(),
		K:                 uint32(s.getStateBigInt(big.NewInt(kLoc)).Uint64()),
		PhiRatio:          float32(s.getStateBigInt(big.NewInt(phiRatioLoc)).Uint64()) / decimalMultiplier,
		NotarySetSize:     uint32(s.getStateBigInt(big.NewInt(notarySetSizeLoc)).Uint64()),
		DKGSetSize:        uint32(s.getStateBigInt(big.NewInt(dkgSetSizeLoc)).Uint64()),
		RoundInterval:     s.getStateBigInt(big.NewInt(roundIntervalLoc)).Uint64(),
		MinBlockInterval:  s.getStateBigInt(big.NewInt(minBlockIntervalLoc)).Uint64(),
		FineValues:        s.FineValues(),
	}
}

// UpdateConfiguration updates system configuration.
func (s *GovernanceStateHelper) UpdateConfiguration(cfg *params.DexconConfig) {
	s.setStateBigInt(big.NewInt(minStakeLoc), cfg.MinStake)
	s.setStateBigInt(big.NewInt(lockupPeriodLoc), big.NewInt(int64(cfg.LockupPeriod)))
	s.setStateBigInt(big.NewInt(miningVelocityLoc), big.NewInt(int64(cfg.MiningVelocity*decimalMultiplier)))
	s.setStateBigInt(big.NewInt(nextHalvingSupplyLoc), cfg.NextHalvingSupply)
	s.setStateBigInt(big.NewInt(lastHalvedAmountLoc), cfg.LastHalvedAmount)
	s.setStateBigInt(big.NewInt(blockGasLimitLoc), big.NewInt(int64(cfg.BlockGasLimit)))
	s.setStateBigInt(big.NewInt(numChainsLoc), big.NewInt(int64(cfg.NumChains)))
	s.setStateBigInt(big.NewInt(lambdaBALoc), big.NewInt(int64(cfg.LambdaBA)))
	s.setStateBigInt(big.NewInt(lambdaDKGLoc), big.NewInt(int64(cfg.LambdaDKG)))
	s.setStateBigInt(big.NewInt(kLoc), big.NewInt(int64(cfg.K)))
	s.setStateBigInt(big.NewInt(phiRatioLoc), big.NewInt(int64(cfg.PhiRatio*decimalMultiplier)))
	s.setStateBigInt(big.NewInt(notarySetSizeLoc), big.NewInt(int64(cfg.NotarySetSize)))
	s.setStateBigInt(big.NewInt(dkgSetSizeLoc), big.NewInt(int64(cfg.DKGSetSize)))
	s.setStateBigInt(big.NewInt(roundIntervalLoc), big.NewInt(int64(cfg.RoundInterval)))
	s.setStateBigInt(big.NewInt(minBlockIntervalLoc), big.NewInt(int64(cfg.MinBlockInterval)))
	s.SetFineValues(cfg.FineValues)
}

type rawConfigStruct struct {
	MinStake         *big.Int
	LockupPeriod     *big.Int
	MiningVelocity   *big.Int
	BlockGasLimit    *big.Int
	NumChains        *big.Int
	LambdaBA         *big.Int
	LambdaDKG        *big.Int
	K                *big.Int
	PhiRatio         *big.Int
	NotarySetSize    *big.Int
	DKGSetSize       *big.Int
	RoundInterval    *big.Int
	MinBlockInterval *big.Int
	FineValues       []*big.Int
}

// UpdateConfigurationRaw updates system configuration.
func (s *GovernanceStateHelper) UpdateConfigurationRaw(cfg *rawConfigStruct) {
	s.setStateBigInt(big.NewInt(minStakeLoc), cfg.MinStake)
	s.setStateBigInt(big.NewInt(lockupPeriodLoc), cfg.LockupPeriod)
	s.setStateBigInt(big.NewInt(miningVelocityLoc), cfg.MiningVelocity)
	s.setStateBigInt(big.NewInt(blockGasLimitLoc), cfg.BlockGasLimit)
	s.setStateBigInt(big.NewInt(numChainsLoc), cfg.NumChains)
	s.setStateBigInt(big.NewInt(lambdaBALoc), cfg.LambdaBA)
	s.setStateBigInt(big.NewInt(lambdaDKGLoc), cfg.LambdaDKG)
	s.setStateBigInt(big.NewInt(kLoc), cfg.K)
	s.setStateBigInt(big.NewInt(phiRatioLoc), cfg.PhiRatio)
	s.setStateBigInt(big.NewInt(notarySetSizeLoc), cfg.NotarySetSize)
	s.setStateBigInt(big.NewInt(dkgSetSizeLoc), cfg.DKGSetSize)
	s.setStateBigInt(big.NewInt(roundIntervalLoc), cfg.RoundInterval)
	s.setStateBigInt(big.NewInt(minBlockIntervalLoc), cfg.MinBlockInterval)
	s.SetFineValues(cfg.FineValues)
}

// event ConfigurationChanged();
func (s *GovernanceStateHelper) emitConfigurationChangedEvent() {
	s.StateDB.AddLog(&types.Log{
		Address: GovernanceContractAddress,
		Topics:  []common.Hash{events["ConfigurationChanged"].Id()},
		Data:    []byte{},
	})
}

// event CRSProposed(uint256 round, bytes32 crs);
func (s *GovernanceStateHelper) emitCRSProposed(round *big.Int, crs common.Hash) {
	s.StateDB.AddLog(&types.Log{
		Address: GovernanceContractAddress,
		Topics:  []common.Hash{events["CRSProposed"].Id(), common.BigToHash(round)},
		Data:    crs.Bytes(),
	})
}

// event Staked(address indexed NodeAddress, uint256 Amount);
func (s *GovernanceStateHelper) emitStaked(nodeAddr common.Address) {
	s.StateDB.AddLog(&types.Log{
		Address: GovernanceContractAddress,
		Topics:  []common.Hash{events["Staked"].Id(), nodeAddr.Hash()},
		Data:    []byte{},
	})
}

// event Unstaked(address indexed NodeAddress);
func (s *GovernanceStateHelper) emitUnstaked(nodeAddr common.Address) {
	s.StateDB.AddLog(&types.Log{
		Address: GovernanceContractAddress,
		Topics:  []common.Hash{events["Unstaked"].Id(), nodeAddr.Hash()},
		Data:    []byte{},
	})
}

// event Delegated(address indexed NodeAddress, address indexed DelegatorAddress, uint256 Amount);
func (s *GovernanceStateHelper) emitDelegated(nodeAddr, delegatorAddr common.Address, amount *big.Int) {
	s.StateDB.AddLog(&types.Log{
		Address: GovernanceContractAddress,
		Topics:  []common.Hash{events["Delegated"].Id(), nodeAddr.Hash(), delegatorAddr.Hash()},
		Data:    common.BigToHash(amount).Bytes(),
	})
}

// event Undelegated(address indexed NodeAddress, address indexed DelegatorAddress);
func (s *GovernanceStateHelper) emitUndelegated(nodeAddr, delegatorAddr common.Address) {
	s.StateDB.AddLog(&types.Log{
		Address: GovernanceContractAddress,
		Topics:  []common.Hash{events["Undelegated"].Id(), nodeAddr.Hash(), delegatorAddr.Hash()},
		Data:    []byte{},
	})
}

// event Withdrawn(address indexed NodeAddress, uint256 Amount);
func (s *GovernanceStateHelper) emitWithdrawn(nodeAddr common.Address, amount *big.Int) {
	s.StateDB.AddLog(&types.Log{
		Address: GovernanceContractAddress,
		Topics:  []common.Hash{events["Withdrawn"].Id(), nodeAddr.Hash()},
		Data:    common.BigToHash(amount).Bytes(),
	})
}

// event ForkReported(address indexed NodeAddress, address indexed Type, bytes Arg1, bytes Arg2);
func (s *GovernanceStateHelper) emitForkReported(nodeAddr common.Address, reportType *big.Int, arg1, arg2 []byte) {

	t, err := abi.NewType("bytes")
	if err != nil {
		panic(err)
	}

	arg := abi.Arguments{
		abi.Argument{
			Name:    "Arg1",
			Type:    t,
			Indexed: false,
		},
		abi.Argument{
			Name:    "Arg2",
			Type:    t,
			Indexed: false,
		},
	}

	data, err := arg.Pack(arg1, arg2)
	if err != nil {
		panic(err)
	}
	s.StateDB.AddLog(&types.Log{
		Address: GovernanceContractAddress,
		Topics:  []common.Hash{events["ForkReported"].Id(), nodeAddr.Hash()},
		Data:    data,
	})
}

// event Fined(address indexed NodeAddress, uint256 Amount);
func (s *GovernanceStateHelper) emitFined(nodeAddr common.Address, amount *big.Int) {
	s.StateDB.AddLog(&types.Log{
		Address: GovernanceContractAddress,
		Topics:  []common.Hash{events["Fined"].Id(), nodeAddr.Hash()},
		Data:    common.BigToHash(amount).Bytes(),
	})
}

// event FinePaid(address indexed NodeAddress, uint256 Amount);
func (s *GovernanceStateHelper) emitFinePaid(nodeAddr common.Address, amount *big.Int) {
	s.StateDB.AddLog(&types.Log{
		Address: GovernanceContractAddress,
		Topics:  []common.Hash{events["FinePaid"].Id(), nodeAddr.Hash()},
		Data:    common.BigToHash(amount).Bytes(),
	})
}

// GovernanceContract represents the governance contract of DEXCON.
type GovernanceContract struct {
	evm      *EVM
	state    GovernanceStateHelper
	contract *Contract
}

func newGovernanceContract(evm *EVM, contract *Contract) *GovernanceContract {
	return &GovernanceContract{
		evm:      evm,
		state:    GovernanceStateHelper{evm.StateDB},
		contract: contract,
	}
}

func (g *GovernanceContract) Address() common.Address {
	return GovernanceContractAddress
}

func (g *GovernanceContract) transfer(from, to common.Address, amount *big.Int) bool {
	// TODO(w): add this to debug trace so it shows up as internal transaction.
	if g.evm.CanTransfer(g.evm.StateDB, from, amount) {
		g.evm.Transfer(g.evm.StateDB, from, to, amount)
		return true
	}
	return false
}

func (g *GovernanceContract) useGas(gas uint64) ([]byte, error) {
	if !g.contract.UseGas(gas) {
		return nil, ErrOutOfGas
	}
	return nil, nil
}

func (g *GovernanceContract) penalize() ([]byte, error) {
	g.useGas(g.contract.Gas)
	return nil, errExecutionReverted
}

func (g *GovernanceContract) inDKGSet(round *big.Int, nodeID coreTypes.NodeID) bool {
	target := coreTypes.NewDKGSetTarget(coreCommon.Hash(g.state.CurrentCRS()))
	ns := coreTypes.NewNodeSet()

	configRound := big.NewInt(0) // If round < core.ConfigRoundShift, use 0.
	if round.Uint64() >= core.ConfigRoundShift {
		configRound = new(big.Int).Sub(round, big.NewInt(int64(core.ConfigRoundShift)))
	}

	statedb, err := g.evm.StateAtNumber(g.state.RoundHeight(configRound).Uint64())
	if err != nil {
		panic(err)
	}

	state := GovernanceStateHelper{statedb}
	for _, x := range state.QualifiedNodes() {
		mpk, err := ecdsa.NewPublicKeyFromByteSlice(x.PublicKey)
		if err != nil {
			panic(err)
		}
		ns.Add(coreTypes.NewNodeID(mpk))
	}

	dkgSet := ns.GetSubSet(int(g.state.DKGSetSize().Uint64()), target)
	_, ok := dkgSet[nodeID]
	return ok
}

func (g *GovernanceContract) addDKGComplaint(round *big.Int, comp []byte) ([]byte, error) {
	if round.Cmp(g.state.Round()) != 0 {
		return g.penalize()
	}

	caller := g.contract.Caller()

	// Finalized caller is not allowed to propose complaint.
	if g.state.DKGFinalized(round, caller) {
		return g.penalize()
	}

	// Calculate 2f
	threshold := new(big.Int).Mul(
		big.NewInt(2),
		new(big.Int).Div(g.state.DKGSetSize(), big.NewInt(3)))

	// If 2f + 1 of DKG set is finalized, one can not propose complaint anymore.
	if g.state.DKGFinalizedsCount(round).Cmp(threshold) > 0 {
		return nil, errExecutionReverted
	}

	var dkgComplaint dkgTypes.Complaint
	if err := rlp.DecodeBytes(comp, &dkgComplaint); err != nil {
		return g.penalize()
	}

	// DKGComplaint must belongs to someone in DKG set.
	if !g.inDKGSet(round, dkgComplaint.ProposerID) {
		return g.penalize()
	}

	verified, _ := coreUtils.VerifyDKGComplaintSignature(&dkgComplaint)
	if !verified {
		return g.penalize()
	}

	mpk, err := g.state.GetDKGMasterPublicKeyByProposerID(
		round, dkgComplaint.PrivateShare.ProposerID)
	if err != nil {
		return g.penalize()
	}

	// Verify DKG complaint is correct.
	ok, err := coreUtils.VerifyDKGComplaint(&dkgComplaint, mpk)
	if !ok || err != nil {
		return g.penalize()
	}

	// Fine the attacker.
	need, err := coreUtils.NeedPenaltyDKGPrivateShare(&dkgComplaint, mpk)
	if err != nil {
		return g.penalize()
	}
	if need {
		fineValue := g.state.FineValue(big.NewInt(ReportTypeInvalidDKG))
		offset := g.state.NodesOffsetByID(Bytes32(dkgComplaint.PrivateShare.ProposerID.Hash))
		node := g.state.Node(offset)
		if err := g.fine(node.Owner, fineValue, comp, nil); err != nil {
			return g.penalize()
		}
	}

	g.state.PushDKGComplaint(round, comp)

	// Set this to relatively high to prevent spamming
	return g.useGas(5000000)
}

func (g *GovernanceContract) addDKGMasterPublicKey(round *big.Int, mpk []byte) ([]byte, error) {
	// Can only add DKG master public key of current and next round.
	if round.Cmp(new(big.Int).Add(g.state.Round(), big.NewInt(1))) > 0 {
		return g.penalize()
	}

	caller := g.contract.Caller()
	offset := g.state.NodesOffsetByAddress(caller)

	// Can not add dkg mpk if not staked.
	if offset.Cmp(big.NewInt(0)) < 0 {
		return nil, errExecutionReverted
	}

	// MPKReady caller is not allowed to propose mpk.
	if g.state.DKGMPKReady(round, caller) {
		return g.penalize()
	}

	// Calculate 2f
	threshold := new(big.Int).Mul(
		big.NewInt(2),
		new(big.Int).Div(g.state.DKGSetSize(), big.NewInt(3)))

	// If 2f + 1 of DKG set is mpk ready, one can not propose mpk anymore.
	if g.state.DKGMPKReadysCount(round).Cmp(threshold) > 0 {
		return nil, errExecutionReverted
	}

	var dkgMasterPK dkgTypes.MasterPublicKey
	if err := rlp.DecodeBytes(mpk, &dkgMasterPK); err != nil {
		return g.penalize()
	}

	// DKGMasterPublicKey must belongs to someone in DKG set.
	if !g.inDKGSet(round, dkgMasterPK.ProposerID) {
		return g.penalize()
	}

	verified, _ := coreUtils.VerifyDKGMasterPublicKeySignature(&dkgMasterPK)
	if !verified {
		return g.penalize()
	}

	g.state.PushDKGMasterPublicKey(round, mpk)

	return g.useGas(100000)
}

func (g *GovernanceContract) addDKGMPKReady(round *big.Int, ready []byte) ([]byte, error) {
	if round.Cmp(g.state.Round()) != 0 {
		return g.penalize()
	}

	caller := g.contract.Caller()

	var dkgReady dkgTypes.MPKReady
	if err := rlp.DecodeBytes(ready, &dkgReady); err != nil {
		return g.penalize()
	}

	// DKGFInalize must belongs to someone in DKG set.
	if !g.inDKGSet(round, dkgReady.ProposerID) {
		return g.penalize()
	}

	verified, _ := coreUtils.VerifyDKGMPKReadySignature(&dkgReady)
	if !verified {
		return g.penalize()
	}

	if !g.state.DKGMPKReady(round, caller) {
		g.state.PutDKGMPKReady(round, caller, true)
		g.state.IncDKGMPKReadysCount(round)
	}

	return g.useGas(100000)
}
func (g *GovernanceContract) addDKGFinalize(round *big.Int, finalize []byte) ([]byte, error) {
	if round.Cmp(g.state.Round()) != 0 {
		return g.penalize()
	}

	caller := g.contract.Caller()

	var dkgFinalize dkgTypes.Finalize
	if err := rlp.DecodeBytes(finalize, &dkgFinalize); err != nil {
		return g.penalize()
	}

	// DKGFInalize must belongs to someone in DKG set.
	if !g.inDKGSet(round, dkgFinalize.ProposerID) {
		return g.penalize()
	}

	verified, _ := coreUtils.VerifyDKGFinalizeSignature(&dkgFinalize)
	if !verified {
		return g.penalize()
	}

	if !g.state.DKGFinalized(round, caller) {
		g.state.PutDKGFinalized(round, caller, true)
		g.state.IncDKGFinalizedsCount(round)
	}

	return g.useGas(100000)
}

func (g *GovernanceContract) delegate(nodeAddr common.Address) ([]byte, error) {
	offset := g.state.NodesOffsetByAddress(nodeAddr)
	if offset.Cmp(big.NewInt(0)) < 0 {
		return nil, errExecutionReverted
	}

	caller := g.contract.Caller()
	value := g.contract.Value()

	// Can not delegate if no fund was sent.
	if value.Cmp(big.NewInt(0)) == 0 {
		return nil, errExecutionReverted
	}

	// Can not delegate if already delegated.
	delegatorOffset := g.state.DelegatorsOffset(nodeAddr, caller)
	if delegatorOffset.Cmp(big.NewInt(0)) >= 0 {
		return nil, errExecutionReverted
	}

	// Add to the total staked of node.
	node := g.state.Node(offset)
	node.Staked = new(big.Int).Add(node.Staked, g.contract.Value())
	g.state.UpdateNode(offset, node)

	// Add to network total staked.
	g.state.IncTotalStaked(g.contract.Value())

	// Push delegator record.
	offset = g.state.LenDelegators(nodeAddr)
	g.state.PushDelegator(nodeAddr, &delegatorInfo{
		Owner:         caller,
		Value:         value,
		UndelegatedAt: big.NewInt(0),
	})
	g.state.PutDelegatorOffset(nodeAddr, caller, offset)
	g.state.emitDelegated(nodeAddr, caller, value)

	return g.useGas(200000)
}

func (g *GovernanceContract) updateConfiguration(cfg *rawConfigStruct) ([]byte, error) {
	// Only owner can update configuration.
	if g.contract.Caller() != g.state.Owner() {
		return nil, errExecutionReverted
	}

	g.state.UpdateConfigurationRaw(cfg)
	g.state.emitConfigurationChangedEvent()
	return nil, nil
}

func (g *GovernanceContract) stake(
	publicKey []byte, name, email, location, url string) ([]byte, error) {

	// Reject invalid inputs.
	if len(name) >= 32 || len(email) >= 32 || len(location) >= 32 || len(url) >= 128 {
		return g.penalize()
	}

	caller := g.contract.Caller()
	offset := g.state.NodesOffsetByAddress(caller)

	// Can not stake if already staked.
	if offset.Cmp(big.NewInt(0)) >= 0 {
		return nil, errExecutionReverted
	}

	offset = g.state.LenNodes()
	node := &nodeInfo{
		Owner:     caller,
		PublicKey: publicKey,
		Staked:    big.NewInt(0),
		Fined:     big.NewInt(0),
		Name:      name,
		Email:     email,
		Location:  location,
		Url:       url,
	}
	g.state.PushNode(node)
	if err := g.state.PutNodeOffsets(node, offset); err != nil {
		return g.penalize()
	}

	// Delegate fund to itself.
	if g.contract.Value().Cmp(big.NewInt(0)) > 0 {
		if ret, err := g.delegate(caller); err != nil {
			return ret, err
		}
	}

	g.state.emitStaked(caller)
	return g.useGas(100000)
}

func (g *GovernanceContract) undelegateHelper(nodeAddr, caller common.Address) ([]byte, error) {
	nodeOffset := g.state.NodesOffsetByAddress(nodeAddr)
	if nodeOffset.Cmp(big.NewInt(0)) < 0 {
		return nil, errExecutionReverted
	}

	offset := g.state.DelegatorsOffset(nodeAddr, caller)
	if offset.Cmp(big.NewInt(0)) < 0 {
		return nil, errExecutionReverted
	}

	node := g.state.Node(nodeOffset)
	if node.Fined.Cmp(big.NewInt(0)) > 0 {
		return nil, errExecutionReverted
	}

	delegator := g.state.Delegator(nodeAddr, offset)

	if delegator.UndelegatedAt.Cmp(big.NewInt(0)) != 0 {
		return nil, errExecutionReverted
	}

	// Set undelegate time.
	delegator.UndelegatedAt = g.evm.Time
	g.state.UpdateDelegator(nodeAddr, offset, delegator)

	// Subtract from the total staked of node.
	node.Staked = new(big.Int).Sub(node.Staked, delegator.Value)
	g.state.UpdateNode(nodeOffset, node)

	// Subtract to network total staked.
	g.state.DecTotalStaked(delegator.Value)

	g.state.emitUndelegated(nodeAddr, caller)

	return g.useGas(100000)
}

func (g *GovernanceContract) undelegate(nodeAddr common.Address) ([]byte, error) {
	return g.undelegateHelper(nodeAddr, g.contract.Caller())
}

func (g *GovernanceContract) withdraw(nodeAddr common.Address) ([]byte, error) {
	caller := g.contract.Caller()

	nodeOffset := g.state.NodesOffsetByAddress(nodeAddr)
	if nodeOffset.Cmp(big.NewInt(0)) < 0 {
		return nil, errExecutionReverted
	}

	offset := g.state.DelegatorsOffset(nodeAddr, caller)
	if offset.Cmp(big.NewInt(0)) < 0 {
		return nil, errExecutionReverted
	}

	delegator := g.state.Delegator(nodeAddr, offset)

	// Not yet undelegated.
	if delegator.UndelegatedAt.Cmp(big.NewInt(0)) == 0 {
		return g.penalize()
	}

	unlockTime := new(big.Int).Add(delegator.UndelegatedAt, g.state.LockupPeriod())
	if g.evm.Time.Cmp(unlockTime) <= 0 {
		return g.penalize()
	}

	length := g.state.LenDelegators(nodeAddr)
	lastIndex := new(big.Int).Sub(length, big.NewInt(1))

	// Delete the delegator.
	if offset.Cmp(lastIndex) != 0 {
		lastNode := g.state.Delegator(nodeAddr, lastIndex)
		g.state.UpdateDelegator(nodeAddr, offset, lastNode)
		g.state.PutDelegatorOffset(nodeAddr, lastNode.Owner, offset)
	}
	g.state.DeleteDelegatorsOffset(nodeAddr, caller)
	g.state.PopLastDelegator(nodeAddr)

	// Return the staked fund.
	if !g.transfer(GovernanceContractAddress, delegator.Owner, delegator.Value) {
		return nil, errExecutionReverted
	}

	g.state.emitWithdrawn(nodeAddr, delegator.Value)

	// We are the last delegator to withdraw the fund, remove the node info.
	if g.state.LenDelegators(nodeAddr).Cmp(big.NewInt(0)) == 0 {
		length := g.state.LenNodes()
		lastIndex := new(big.Int).Sub(length, big.NewInt(1))

		// Delete the node.
		if offset.Cmp(lastIndex) != 0 {
			lastNode := g.state.Node(lastIndex)
			g.state.UpdateNode(offset, lastNode)
			if err := g.state.PutNodeOffsets(lastNode, offset); err != nil {
				panic(err)
			}
		}
		g.state.DeleteNodesOffsetByAddress(nodeAddr)
		g.state.PopLastNode()
	}

	return g.useGas(100000)
}

func (g *GovernanceContract) unstake() ([]byte, error) {
	caller := g.contract.Caller()
	offset := g.state.NodesOffsetByAddress(caller)
	if offset.Cmp(big.NewInt(0)) < 0 {
		return nil, errExecutionReverted
	}

	node := g.state.Node(offset)
	if node.Fined.Cmp(big.NewInt(0)) > 0 {
		return nil, errExecutionReverted
	}

	// Undelegate all delegators.
	lenDelegators := g.state.LenDelegators(caller)
	i := new(big.Int).Sub(lenDelegators, big.NewInt(1))
	for i.Cmp(big.NewInt(0)) >= 0 {
		delegator := g.state.Delegator(caller, i)
		if ret, err := g.undelegateHelper(caller, delegator.Owner); err != nil {
			return ret, err
		}
		i = i.Sub(i, big.NewInt(1))
	}

	g.state.emitUnstaked(caller)

	return g.useGas(100000)
}

func (g *GovernanceContract) payFine(nodeAddr common.Address) ([]byte, error) {
	caller := g.contract.Caller()

	nodeOffset := g.state.NodesOffsetByAddress(nodeAddr)
	if nodeOffset.Cmp(big.NewInt(0)) < 0 {
		return nil, errExecutionReverted
	}

	offset := g.state.DelegatorsOffset(nodeAddr, caller)
	if offset.Cmp(big.NewInt(0)) < 0 {
		return nil, errExecutionReverted
	}

	node := g.state.Node(nodeOffset)
	if node.Fined.Cmp(big.NewInt(0)) <= 0 || node.Fined.Cmp(g.contract.Value()) < 0 {
		return nil, errExecutionReverted
	}

	node.Fined = new(big.Int).Sub(node.Fined, g.contract.Value())
	g.state.UpdateNode(nodeOffset, node)

	// TODO: paid fine should be added to award pool.

	g.state.emitFinePaid(nodeAddr, g.contract.Value())

	return g.useGas(100000)
}

func (g *GovernanceContract) proposeCRS(nextRound *big.Int, signedCRS []byte) ([]byte, error) {
	round := g.state.Round()

	if nextRound.Cmp(round) <= 0 {
		return nil, errExecutionReverted
	}

	prevCRS := g.state.CRS(round)

	// Prepare DKGMasterPublicKeys.
	dkgMasterPKs := g.state.UniqueDKGMasterPublicKeys(round)

	// Prepare DKGComplaints.
	var dkgComplaints []*dkgTypes.Complaint
	for _, comp := range g.state.DKGComplaints(round) {
		x := new(dkgTypes.Complaint)
		if err := rlp.DecodeBytes(comp, x); err != nil {
			panic(err)
		}
		dkgComplaints = append(dkgComplaints, x)
	}

	threshold := int(g.state.DKGSetSize().Uint64()/3 + 1)

	dkgGPK, err := core.NewDKGGroupPublicKey(
		round.Uint64(), dkgMasterPKs, dkgComplaints, threshold)
	if err != nil {
		return nil, errExecutionReverted
	}
	signature := coreCrypto.Signature{
		Type:      "bls",
		Signature: signedCRS,
	}
	if !dkgGPK.VerifySignature(coreCommon.Hash(prevCRS), signature) {
		return g.penalize()
	}

	// Save new CRS into state and increase round.
	newCRS := crypto.Keccak256(signedCRS)
	crs := common.BytesToHash(newCRS)

	g.state.PushCRS(crs)
	g.state.emitCRSProposed(nextRound, crs)

	// To encourage DKG set to propose the correct value, correctly submitting
	// this should cause nothing.
	return g.useGas(0)
}

type sortBytes [][]byte

func (s sortBytes) Less(i, j int) bool {
	return bytes.Compare(s[i], s[j]) < 0
}

func (s sortBytes) Swap(i, j int) {
	s[i], s[j] = s[j], s[i]
}

func (s sortBytes) Len() int {
	return len(s)
}

func (g *GovernanceContract) fine(nodeAddr common.Address, amount *big.Int, payloads ...[]byte) error {
	sort.Sort(sortBytes(payloads))

	hash := Bytes32(crypto.Keccak256Hash(payloads...))
	if g.state.FineRecords(hash) {
		return errors.New("already fined")
	}
	g.state.SetFineRecords(hash, true)

	nodeOffset := g.state.NodesOffsetByAddress(nodeAddr)
	if nodeOffset.Cmp(big.NewInt(0)) < 0 {
		return errExecutionReverted
	}

	// Set fined value.
	node := g.state.Node(nodeOffset)
	node.Fined = new(big.Int).Add(node.Fined, amount)
	g.state.UpdateNode(nodeOffset, node)

	g.state.emitFined(nodeAddr, amount)

	return nil
}

func (g *GovernanceContract) report(reportType *big.Int, arg1, arg2 []byte) ([]byte, error) {
	typeEnum := ReportType(reportType.Uint64())
	var reportedNodeID coreTypes.NodeID

	switch typeEnum {
	case ReportTypeForkVote:
		vote1 := new(coreTypes.Vote)
		if err := rlp.DecodeBytes(arg1, vote1); err != nil {
			return g.penalize()
		}
		vote2 := new(coreTypes.Vote)
		if err := rlp.DecodeBytes(arg2, vote2); err != nil {
			return g.penalize()
		}
		need, err := coreUtils.NeedPenaltyForkVote(vote1, vote2)
		if !need || err != nil {
			return g.penalize()
		}
		reportedNodeID = vote1.ProposerID
	case ReportTypeForkBlock:
		block1 := new(coreTypes.Block)
		if err := rlp.DecodeBytes(arg1, block1); err != nil {
			return g.penalize()
		}
		block2 := new(coreTypes.Block)
		if err := rlp.DecodeBytes(arg2, block2); err != nil {
			return g.penalize()
		}
		need, err := coreUtils.NeedPenaltyForkBlock(block1, block2)
		if !need || err != nil {
			return g.penalize()
		}
		reportedNodeID = block1.ProposerID
	default:
		return g.penalize()
	}

	offset := g.state.NodesOffsetByID(Bytes32(reportedNodeID.Hash))
	node := g.state.Node(offset)

	g.state.emitForkReported(node.Owner, reportType, arg1, arg2)

	fineValue := g.state.FineValue(reportType)
	if err := g.fine(node.Owner, fineValue, arg1, arg2); err != nil {
		return nil, errExecutionReverted
	}
	return nil, nil
}

func (g *GovernanceContract) transferOwnership(newOwner common.Address) ([]byte, error) {
	// Only owner can update configuration.
	if g.contract.Caller() != g.state.Owner() {
		return nil, errExecutionReverted
	}
	g.state.SetOwner(newOwner)
	return nil, nil
}

func (g *GovernanceContract) snapshotRound(round, height *big.Int) ([]byte, error) {
	// Validate if this mapping is correct. Only block proposer need to verify this.
	if g.evm.IsBlockProposer() {
		realHeight, ok := g.evm.GetRoundHeight(round.Uint64())
		if !ok {
			return g.penalize()
		}

		if height.Cmp(new(big.Int).SetUint64(realHeight)) != 0 {
			return g.penalize()
		}
	}

	// Only allow updating the next round.
	nextRound := g.state.LenRoundHeight()
	if round.Cmp(nextRound) != 0 {
		// No need to penalize, since the only possibility at this point is the
		// round height is already snapshoted.
		return nil, errExecutionReverted
	}

	g.state.PushRoundHeight(height)
	return nil, nil
}