// Copyright 2014 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 vm

import (
	"crypto/sha256"
	"encoding/binary"
	"errors"
	"fmt"
	"math/big"
	"slices"
	"sync"

	"github.com/autonity/autonity/common"
	"github.com/autonity/autonity/common/math"
	"github.com/autonity/autonity/consensus/tendermint/bft"
	"github.com/autonity/autonity/consensus/tendermint/core/message"
	"github.com/autonity/autonity/core/types"
	"github.com/autonity/autonity/crypto"
	"github.com/autonity/autonity/crypto/blake2b"
	"github.com/autonity/autonity/crypto/bls12381"
	"github.com/autonity/autonity/crypto/blst"
	"github.com/autonity/autonity/crypto/bn256"
	"github.com/autonity/autonity/p2p/enode"
	"github.com/autonity/autonity/params"

	// lint:ignore SA1019 Needed for precompile
	"golang.org/x/crypto/ripemd160"
)

const (
	ArrayLenBytes = 32
	POPBytes      = 164
)

var (
	// PrecompiledContractRWMutex to fix the race condition of precompiled contracts loading on the start-up phase.
	PrecompiledContractRWMutex = sync.RWMutex{}
	failure32Byte              = make([]byte, 32)
	// error codes of the execution of precompiled contract to verify the input Proof.
	successResult = common.LeftPadBytes([]byte{1}, 32)
)

// PrecompiledContract is the basic interface for native Go contracts. The implementation
// requires a deterministic gas count based on the input size of the Run method of the
// contract.
type PrecompiledContract interface {
	RequiredGas(input []byte) uint64                                                       // RequiredPrice calculates the contract gas use
	Run(input []byte, blockNumber uint64, evm *EVM, caller common.Address) ([]byte, error) // Run runs the precompiled contract
}

// PrecompiledContractsHomestead contains the default set of pre-compiled Ethereum
// contracts used in the Frontier and Homestead releases.
var PrecompiledContractsHomestead = map[common.Address]PrecompiledContract{
	common.BytesToAddress([]byte{1}): &ecrecover{},
	common.BytesToAddress([]byte{2}): &sha256hash{},
	common.BytesToAddress([]byte{3}): &ripemd160hash{},
	common.BytesToAddress([]byte{4}): &dataCopy{},

	common.BytesToAddress([]byte{248}): &absenteesComputer{},
	common.BytesToAddress([]byte{249}): &Upgrader{},
	common.BytesToAddress([]byte{250}): &CommitteeSelector{},
	common.BytesToAddress([]byte{251}): &POPVerifier{},
	// addresses 252 to 254 are reserved for accountability contracts
	common.BytesToAddress([]byte{255}): &checkEnode{},
}

// PrecompiledContractsByzantium contains the default set of pre-compiled Ethereum
// contracts used in the Byzantium release.
var PrecompiledContractsByzantium = map[common.Address]PrecompiledContract{
	common.BytesToAddress([]byte{1}): &ecrecover{},
	common.BytesToAddress([]byte{2}): &sha256hash{},
	common.BytesToAddress([]byte{3}): &ripemd160hash{},
	common.BytesToAddress([]byte{4}): &dataCopy{},
	common.BytesToAddress([]byte{5}): &bigModExp{eip2565: false},
	common.BytesToAddress([]byte{6}): &bn256AddByzantium{},
	common.BytesToAddress([]byte{7}): &bn256ScalarMulByzantium{},
	common.BytesToAddress([]byte{8}): &bn256PairingByzantium{},

	common.BytesToAddress([]byte{248}): &absenteesComputer{},
	common.BytesToAddress([]byte{249}): &Upgrader{},
	common.BytesToAddress([]byte{250}): &CommitteeSelector{},
	common.BytesToAddress([]byte{251}): &POPVerifier{},
	// addresses 252 to 254 are reserved for accountability contracts
	common.BytesToAddress([]byte{255}): &checkEnode{},
}

// PrecompiledContractsIstanbul contains the default set of pre-compiled Ethereum
// contracts used in the Istanbul release.
var PrecompiledContractsIstanbul = map[common.Address]PrecompiledContract{
	common.BytesToAddress([]byte{1}): &ecrecover{},
	common.BytesToAddress([]byte{2}): &sha256hash{},
	common.BytesToAddress([]byte{3}): &ripemd160hash{},
	common.BytesToAddress([]byte{4}): &dataCopy{},
	common.BytesToAddress([]byte{5}): &bigModExp{eip2565: false},
	common.BytesToAddress([]byte{6}): &bn256AddIstanbul{},
	common.BytesToAddress([]byte{7}): &bn256ScalarMulIstanbul{},
	common.BytesToAddress([]byte{8}): &bn256PairingIstanbul{},
	common.BytesToAddress([]byte{9}): &blake2F{},

	common.BytesToAddress([]byte{248}): &absenteesComputer{},
	common.BytesToAddress([]byte{249}): &Upgrader{},
	common.BytesToAddress([]byte{250}): &CommitteeSelector{},
	common.BytesToAddress([]byte{251}): &POPVerifier{},
	// addresses 252 to 254 are reserved for accountability contracts
	common.BytesToAddress([]byte{255}): &checkEnode{},
}

// PrecompiledContractsBerlin contains the default set of pre-compiled Ethereum
// contracts used in the Berlin release.
var PrecompiledContractsBerlin = map[common.Address]PrecompiledContract{
	common.BytesToAddress([]byte{1}): &ecrecover{},
	common.BytesToAddress([]byte{2}): &sha256hash{},
	common.BytesToAddress([]byte{3}): &ripemd160hash{},
	common.BytesToAddress([]byte{4}): &dataCopy{},
	common.BytesToAddress([]byte{5}): &bigModExp{eip2565: true},
	common.BytesToAddress([]byte{6}): &bn256AddIstanbul{},
	common.BytesToAddress([]byte{7}): &bn256ScalarMulIstanbul{},
	common.BytesToAddress([]byte{8}): &bn256PairingIstanbul{},
	common.BytesToAddress([]byte{9}): &blake2F{},

	common.BytesToAddress([]byte{248}): &absenteesComputer{},
	common.BytesToAddress([]byte{249}): &Upgrader{},
	common.BytesToAddress([]byte{250}): &CommitteeSelector{},
	common.BytesToAddress([]byte{251}): &POPVerifier{},
	// addresses 252 to 254 are reserved for accountability contracts
	common.BytesToAddress([]byte{255}): &checkEnode{},
}

// PrecompiledContractsBLS contains the set of pre-compiled Ethereum
// contracts specified in EIP-2537. These are exported for testing purposes.
var PrecompiledContractsBLS = map[common.Address]PrecompiledContract{
	common.BytesToAddress([]byte{10}): &bls12381G1Add{},
	common.BytesToAddress([]byte{11}): &bls12381G1Mul{},
	common.BytesToAddress([]byte{12}): &bls12381G1MultiExp{},
	common.BytesToAddress([]byte{13}): &bls12381G2Add{},
	common.BytesToAddress([]byte{14}): &bls12381G2Mul{},
	common.BytesToAddress([]byte{15}): &bls12381G2MultiExp{},
	common.BytesToAddress([]byte{16}): &bls12381Pairing{},
	common.BytesToAddress([]byte{17}): &bls12381MapG1{},
	common.BytesToAddress([]byte{18}): &bls12381MapG2{},

	common.BytesToAddress([]byte{248}): &absenteesComputer{},
	common.BytesToAddress([]byte{249}): &Upgrader{},
	common.BytesToAddress([]byte{250}): &CommitteeSelector{},
	common.BytesToAddress([]byte{251}): &POPVerifier{},
	// addresses 252 to 254 are reserved for accountability contracts
	common.BytesToAddress([]byte{255}): &checkEnode{},
}

var (
	PrecompiledAddressesBerlin    []common.Address
	PrecompiledAddressesIstanbul  []common.Address
	PrecompiledAddressesByzantium []common.Address
	PrecompiledAddressesHomestead []common.Address
)

func init() {
	for k := range PrecompiledContractsHomestead {
		PrecompiledAddressesHomestead = append(PrecompiledAddressesHomestead, k)
	}
	for k := range PrecompiledContractsByzantium {
		PrecompiledAddressesByzantium = append(PrecompiledAddressesByzantium, k)
	}
	for k := range PrecompiledContractsIstanbul {
		PrecompiledAddressesIstanbul = append(PrecompiledAddressesIstanbul, k)
	}
	for k := range PrecompiledContractsBerlin {
		PrecompiledAddressesBerlin = append(PrecompiledAddressesBerlin, k)
	}
}

// ActivePrecompiles returns the precompiles enabled with the current configuration.
func ActivePrecompiles(rules params.Rules) []common.Address {
	switch {
	case rules.IsBerlin:
		return PrecompiledAddressesBerlin
	case rules.IsIstanbul:
		return PrecompiledAddressesIstanbul
	case rules.IsByzantium:
		return PrecompiledAddressesByzantium
	default:
		return PrecompiledAddressesHomestead
	}
}

// RunPrecompiledContract runs and evaluates the output of a precompiled contract.
// It returns
// - the returned bytes,
// - the _remaining_ gas,
// - any error that occurred
func RunPrecompiledContract(
	p PrecompiledContract, input []byte, suppliedGas uint64, blockNumber uint64, evm *EVM, caller common.Address,
) (ret []byte, remainingGas uint64, err error) {
	gasCost := p.RequiredGas(input)
	if suppliedGas < gasCost {
		return nil, 0, ErrOutOfGas
	}
	suppliedGas -= gasCost
	output, err := p.Run(input, blockNumber, evm, caller)
	return output, suppliedGas, err
}

const (
	KB = 1024
	// offset constants of Validator struct from Autonity.sol
	BondedStakeOffset  = 5
	ConsensusKeyOffset = 17
	StateOffset        = 18
	// Constant Threshold used in CommitteeSelector
	StakeThreshold = 0
	ActiveState    = 0
	// DataLen is the number of bytes each solidity variable occupies in memory if not compacted
	DataLen = common.HashLength
)

var (
	errUnauthorized       = errors.New("caller address not authorized")
	errBadUpgradeTarget   = errors.New("target address not authorized")
	errBadInput           = errors.New("input is invalid")
	errBadCommitteeSize   = errors.New("invalid max committee size")
	errBadValidatorSize   = errors.New("invalid size of validator list")
	errNoActiveValidator  = errors.New("no active validators with positive stake")
	errBadConsensusKeyLen = errors.New("invalid consensus key length")
	errExcludedValidator  = errors.New("excluding validator")
	errNonEmptyProof      = errors.New("activity proof should be empty")
)

type Upgrader struct{}

func (u *Upgrader) RequiredGas(_ []byte) uint64 {
	return params.ProtocolOnlyBaseGas
}

func (u *Upgrader) Run(input []byte, _ uint64, evm *EVM, caller common.Address) ([]byte, error) {
	if caller != params.UpgradeManagerContractAddress {
		return nil, errUnauthorized
	}
	if len(input) < common.AddressLength+1 {
		return nil, errBadInput
	}
	var (
		targetContract = common.Address(input[:common.AddressLength])
		code           = input[common.AddressLength:]
	)
	if !slices.Contains(params.ProtocolContracts, targetContract) {
		return nil, errBadUpgradeTarget
	}
	// input is TARGET_ADDRESS + DEPLOY_CALLDATA
	_, _, _, err := evm.Replace(AccountRef(params.DeployerAddress), code, targetContract)
	return nil, err
}

type CommitteeSelector struct{}

type CommitteeInput struct {
	validatorListSlot         []byte
	validatorsSlot            []byte
	committeeSlot             []byte
	epochTotalBondedStakeSlot []byte
	maxCommitteeSize          uint64
}

func (a *CommitteeSelector) RequiredGas(input []byte) uint64 {
	return params.ProtocolOnlyBaseGas
}

func (a *CommitteeSelector) Run(input []byte, _ uint64, evm *EVM, caller common.Address) ([]byte, error) {
	// skip auth check if run in test mode
	if !evm.chainConfig.TestMode && caller != params.AutonityContractAddress {
		return nil, errUnauthorized
	}
	// input
	if len(input) < 5*DataLen {
		return nil, errBadInput
	}
	inputs := &CommitteeInput{}
	offset := 0
	inputs.validatorListSlot = input[offset : offset+DataLen]
	offset += DataLen
	inputs.validatorsSlot = input[offset : offset+DataLen]
	offset += DataLen
	inputs.committeeSlot = input[offset : offset+DataLen]
	offset += DataLen
	inputs.epochTotalBondedStakeSlot = input[offset : offset+DataLen]
	offset += DataLen
	maxCommitteeSize := big.NewInt(0).SetBytes(input[offset : offset+DataLen])
	if !maxCommitteeSize.IsUint64() {
		return nil, errBadCommitteeSize
	}
	inputs.maxCommitteeSize = maxCommitteeSize.Uint64()

	stateDB := evm.StateDB
	// detailed specifications on how to read state variable from slot: https://docs.soliditylang.org/en/latest/internals/layout_in_storage.html#storage-inplace-encoding
	// validatorListSlot has the size of the array validatorList
	validatorListSizeBig := stateDB.GetState(caller, common.BytesToHash(inputs.validatorListSlot)).Big()
	if !validatorListSizeBig.IsUint64() {
		return nil, errBadValidatorSize
	}
	validatorListSize := int(validatorListSizeBig.Uint64())
	addressOffset := crypto.Keccak256Hash(inputs.validatorListSlot).Big()
	stakeThreshold := big.NewInt(StakeThreshold)
	activeState := big.NewInt(ActiveState)

	// get validators from DB
	// scope to improve: read validators from DB concurrently
	// NOTE: (if read concurrently) the order of the validators in the array after reading is done should not be depenedent on concurrent thread completion (ideally)
	validators := make([]types.CommitteeMember, 0, validatorListSize)
	mapKey := make([]byte, DataLen*2)
	copy(mapKey[DataLen:], inputs.validatorsSlot)
	for i := 0; i < validatorListSize; i++ {
		if user, err := a.getValidatorInfo(mapKey, addressOffset.Bytes(), stakeThreshold, activeState, caller, stateDB); err == nil {
			validators = append(validators, user)
		}
		// goto next slot
		addressOffset.Add(addressOffset, common.Big1)
	}

	if len(validators) == 0 {
		return nil, errNoActiveValidator
	}

	committeeSize := min(len(validators), int(inputs.maxCommitteeSize))
	types.SortCommitteeMembers(validators)
	err := a.updateCommittee(inputs, validators, committeeSize, caller, stateDB)
	return nil, err
}

func (a *CommitteeSelector) updateCommittee(
	inputs *CommitteeInput, validators []types.CommitteeMember, committeeSize int, caller common.Address, stateDB StateDB,
) error {
	// write committee to persistent storage
	oldCommitteeSize := int(stateDB.GetState(caller, common.BytesToHash(inputs.committeeSlot)).Big().Uint64())
	// 8 bytes for uint64
	committeeLenBytes := make([]byte, 8)
	binary.BigEndian.PutUint64(committeeLenBytes, uint64(committeeSize))
	// save committeeSize in committeeSlot
	stateDB.SetState(caller, common.BytesToHash(inputs.committeeSlot), common.BytesToHash(committeeLenBytes))
	// put new committee members : type CommitteeMember
	committeeOffset := crypto.Keccak256Hash(inputs.committeeSlot).Big()
	totalStake := big.NewInt(0)
	mapKey := make([]byte, DataLen*2)
	copy(mapKey[DataLen:], inputs.validatorsSlot)
	for i := 0; i < committeeSize; i++ {
		// the order has to be in sync with Committee struct in Autonity.sol
		// save address
		stateDB.SetState(caller, common.BigToHash(committeeOffset), validators[i].Address.Hash())
		// goto next slot
		committeeOffset.Add(committeeOffset, common.Big1)
		// save voting power
		stateDB.SetState(caller, common.BigToHash(committeeOffset), common.BytesToHash(validators[i].VotingPower.Bytes()))
		// goto next slot
		committeeOffset.Add(committeeOffset, common.Big1)

		// read and then save consensus key (bytes)
		copy(mapKey[DataLen-common.AddressLength:DataLen], validators[i].Address.Bytes())
		mapItemSlot := crypto.Keccak256Hash(mapKey).Big()
		mapItemSlot.Add(mapItemSlot, big.NewInt(ConsensusKeyOffset))
		consensusKeyBytes := stateDB.GetState(caller, common.BigToHash(mapItemSlot)).Bytes()
		// if last bit is not set, then data is short and contains all the info
		// otherwise we have (2*length + 1) at the slot and the bytes is saved as bytes1[]
		stateDB.SetState(caller, common.BigToHash(committeeOffset), common.BytesToHash(consensusKeyBytes))
		if (consensusKeyBytes[DataLen-1] & 1) == 1 {
			keyLenBig := new(big.Int).SetBytes(consensusKeyBytes)
			if !keyLenBig.IsUint64() {
				return errBadConsensusKeyLen
			}
			keyLen := int(keyLenBig.Int64()-1) / 2
			bytesSlot := make([]byte, DataLen)
			// the offset is calculated the same way as dynamic array
			readOffset := crypto.Keccak256Hash(mapItemSlot.FillBytes(bytesSlot)).Big()
			writeOffset := crypto.Keccak256Hash(committeeOffset.FillBytes(bytesSlot)).Big()
			// bytes1 is only 1 byte long, so 32 elements are compacted in a single slot
			for j := 0; j < keyLen; j += 32 {
				keyChunk := stateDB.GetState(caller, common.BigToHash(readOffset))
				stateDB.SetState(caller, common.BigToHash(writeOffset), keyChunk)
				readOffset.Add(readOffset, common.Big1)
				writeOffset.Add(writeOffset, common.Big1)
			}
		}
		// goto next slot
		committeeOffset.Add(committeeOffset, common.Big1)

		totalStake = totalStake.Add(totalStake, validators[i].VotingPower)
	}
	// write epochTotalBondedStake
	stateDB.SetState(caller, common.BytesToHash(inputs.epochTotalBondedStakeSlot), common.BytesToHash(totalStake.Bytes()))

	// delete old committee members, if any
	for i := committeeSize; i < oldCommitteeSize; i++ {
		// delete address
		stateDB.SetState(caller, common.BigToHash(committeeOffset), common.Hash{})
		// goto next slot
		committeeOffset.Add(committeeOffset, common.Big1)
		// delete voting power
		stateDB.SetState(caller, common.BigToHash(committeeOffset), common.Hash{})
		// goto next slot
		committeeOffset.Add(committeeOffset, common.Big1)
		// delete consensus key
		// read its length first
		consensusKeyBytes := stateDB.GetState(caller, common.BigToHash(committeeOffset)).Bytes()
		stateDB.SetState(caller, common.BigToHash(committeeOffset), common.Hash{})
		if (consensusKeyBytes[DataLen-1] & 1) == 1 {
			// consens key is a big bytes data, stored in different slots
			keyLenBig := new(big.Int).SetBytes(consensusKeyBytes)
			if !keyLenBig.IsUint64() {
				return errBadConsensusKeyLen
			}
			keyLen := int(keyLenBig.Int64()-1) / 2
			bytesSlot := make([]byte, DataLen)
			// the offset is calculated the same way as dynamic array
			keyChunkOffset := crypto.Keccak256Hash(committeeOffset.FillBytes(bytesSlot)).Big()
			// bytes1 is only 1 byte long, so 32 elements are compacted in a single slot
			for j := 0; j < keyLen; j += 32 {
				stateDB.SetState(caller, common.BigToHash(keyChunkOffset), common.Hash{})
				keyChunkOffset.Add(keyChunkOffset, common.Big1)
			}
		}
		// goto next slot
		committeeOffset.Add(committeeOffset, common.Big1)
	}
	return nil
}

// solidity storage layout: https://docs.soliditylang.org/en/latest/internals/layout_in_storage.html#storage-inplace-encoding
func (a *CommitteeSelector) getValidatorInfo(
	mapKey []byte, addressSlot []byte, stakeThreshold *big.Int, expectedState *big.Int, caller common.Address, stateDB StateDB,
) (types.CommitteeMember, error) {

	nodeAddress := common.BytesToAddress(stateDB.GetState(caller, common.BytesToHash(addressSlot)).Bytes())
	// We need reference of validator mapping + relative offset of bondedStake + relative offset of state
	copy(mapKey[DataLen-common.AddressLength:DataLen], nodeAddress.Bytes())
	mapItemSlot := crypto.Keccak256Hash(mapKey).Big()
	stakeSlot := new(big.Int).Add(mapItemSlot, big.NewInt(BondedStakeOffset)).Bytes()
	bondedStake := stateDB.GetState(caller, common.BytesToHash(stakeSlot)).Big()
	stateSlot := new(big.Int).Add(mapItemSlot, big.NewInt(StateOffset)).Bytes()
	state := stateDB.GetState(caller, common.BytesToHash(stateSlot)).Big()
	// take validator if the stake is greater than threshold, for now threshold = 0
	if bondedStake.Cmp(stakeThreshold) == 1 && state.Cmp(expectedState) == 0 {
		return types.CommitteeMember{
			Address:     nodeAddress,
			VotingPower: bondedStake,
		}, nil
	}
	return types.CommitteeMember{}, errExcludedValidator
}

// ECRECOVER implemented as a native contract.
type ecrecover struct{}

func (c *ecrecover) RequiredGas(input []byte) uint64 {
	return params.EcrecoverGas
}

func (c *ecrecover) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	const ecRecoverInputLength = 128

	input = common.RightPadBytes(input, ecRecoverInputLength)
	// "input" is (hash, v, r, s), each 32 bytes
	// but for ecrecover we want (r, s, v)

	r := new(big.Int).SetBytes(input[64:96])
	s := new(big.Int).SetBytes(input[96:128])
	v := input[63] - 27

	// tighter sig s values input homestead only apply to tx sigs
	if !allZero(input[32:63]) || !crypto.ValidateSignatureValues(v, r, s, false) {
		return nil, nil
	}
	// We must make sure not to modify the 'input', so placing the 'v' along with
	// the signature needs to be done on a new allocation
	sig := make([]byte, 65)
	copy(sig, input[64:128])
	sig[64] = v
	// v needs to be at the end for libsecp256k1
	pubKey, err := crypto.Ecrecover(input[:32], sig)
	// make sure the public key is a valid one
	if err != nil {
		return nil, nil
	}

	// the first byte of pubkey is bitcoin heritage
	return common.LeftPadBytes(crypto.Keccak256(pubKey[1:])[12:], 32), nil
}

// SHA256 implemented as a native contract.
type sha256hash struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
//
// This method does not require any overflow checking as the input size gas costs
// required for anything significant is so high it's impossible to pay for.
func (c *sha256hash) RequiredGas(input []byte) uint64 {
	return uint64(len(input)+31)/32*params.Sha256PerWordGas + params.Sha256BaseGas
}
func (c *sha256hash) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	h := sha256.Sum256(input)
	return h[:], nil
}

// RIPEMD160 implemented as a native contract.
type ripemd160hash struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
//
// This method does not require any overflow checking as the input size gas costs
// required for anything significant is so high it's impossible to pay for.
func (c *ripemd160hash) RequiredGas(input []byte) uint64 {
	return uint64(len(input)+31)/32*params.Ripemd160PerWordGas + params.Ripemd160BaseGas
}
func (c *ripemd160hash) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	ripemd := ripemd160.New()
	ripemd.Write(input)
	return common.LeftPadBytes(ripemd.Sum(nil), 32), nil
}

// data copy implemented as a native contract.
type dataCopy struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
//
// This method does not require any overflow checking as the input size gas costs
// required for anything significant is so high it's impossible to pay for.
func (c *dataCopy) RequiredGas(input []byte) uint64 {
	return uint64(len(input)+31)/32*params.IdentityPerWordGas + params.IdentityBaseGas
}
func (c *dataCopy) Run(in []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	return in, nil
}

// bigModExp implements a native big integer exponential modular operation.
type bigModExp struct {
	eip2565 bool
}

var (
	big0      = big.NewInt(0)
	big1      = big.NewInt(1)
	big3      = big.NewInt(3)
	big4      = big.NewInt(4)
	big7      = big.NewInt(7)
	big8      = big.NewInt(8)
	big16     = big.NewInt(16)
	big20     = big.NewInt(20)
	big32     = big.NewInt(32)
	big64     = big.NewInt(64)
	big96     = big.NewInt(96)
	big480    = big.NewInt(480)
	big1024   = big.NewInt(1024)
	big3072   = big.NewInt(3072)
	big199680 = big.NewInt(199680)
)

// modexpMultComplexity implements bigModexp multComplexity formula, as defined in EIP-198
//
// def mult_complexity(x):
//
//	if x <= 64: return x ** 2
//	elif x <= 1024: return x ** 2 // 4 + 96 * x - 3072
//	else: return x ** 2 // 16 + 480 * x - 199680
//
// where is x is max(length_of_MODULUS, length_of_BASE)
func modexpMultComplexity(x *big.Int) *big.Int {
	switch {
	case x.Cmp(big64) <= 0:
		x.Mul(x, x) // x ** 2
	case x.Cmp(big1024) <= 0:
		// (x ** 2 // 4 ) + ( 96 * x - 3072)
		x = new(big.Int).Add(
			new(big.Int).Div(new(big.Int).Mul(x, x), big4),
			new(big.Int).Sub(new(big.Int).Mul(big96, x), big3072),
		)
	default:
		// (x ** 2 // 16) + (480 * x - 199680)
		x = new(big.Int).Add(
			new(big.Int).Div(new(big.Int).Mul(x, x), big16),
			new(big.Int).Sub(new(big.Int).Mul(big480, x), big199680),
		)
	}
	return x
}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bigModExp) RequiredGas(input []byte) uint64 {
	var (
		baseLen = new(big.Int).SetBytes(getData(input, 0, 32))
		expLen  = new(big.Int).SetBytes(getData(input, 32, 32))
		modLen  = new(big.Int).SetBytes(getData(input, 64, 32))
	)
	if len(input) > 96 {
		input = input[96:]
	} else {
		input = input[:0]
	}
	// Retrieve the head 32 bytes of exp for the adjusted exponent length
	var expHead *big.Int
	if big.NewInt(int64(len(input))).Cmp(baseLen) <= 0 {
		expHead = new(big.Int)
	} else {
		if expLen.Cmp(big32) > 0 {
			expHead = new(big.Int).SetBytes(getData(input, baseLen.Uint64(), 32))
		} else {
			expHead = new(big.Int).SetBytes(getData(input, baseLen.Uint64(), expLen.Uint64()))
		}
	}
	// Calculate the adjusted exponent length
	var msb int
	if bitlen := expHead.BitLen(); bitlen > 0 {
		msb = bitlen - 1
	}
	adjExpLen := new(big.Int)
	if expLen.Cmp(big32) > 0 {
		adjExpLen.Sub(expLen, big32)
		adjExpLen.Mul(big8, adjExpLen)
	}
	adjExpLen.Add(adjExpLen, big.NewInt(int64(msb)))
	// Calculate the gas cost of the operation
	gas := new(big.Int).Set(math.BigMax(modLen, baseLen))
	if c.eip2565 {
		// EIP-2565 has three changes
		// 1. Different multComplexity (inlined here)
		// in EIP-2565 (https://eips.ethereum.org/EIPS/eip-2565):
		//
		// def mult_complexity(x):
		//    ceiling(x/8)^2
		//
		//where is x is max(length_of_MODULUS, length_of_BASE)
		gas = gas.Add(gas, big7)
		gas = gas.Div(gas, big8)
		gas.Mul(gas, gas)

		gas.Mul(gas, math.BigMax(adjExpLen, big1))
		// 2. Different divisor (`GQUADDIVISOR`) (3)
		gas.Div(gas, big3)
		if gas.BitLen() > 64 {
			return math.MaxUint64
		}
		// 3. Minimum price of 200 gas
		if gas.Uint64() < 200 {
			return 200
		}
		return gas.Uint64()
	}
	gas = modexpMultComplexity(gas)
	gas.Mul(gas, math.BigMax(adjExpLen, big1))
	gas.Div(gas, big20)

	if gas.BitLen() > 64 {
		return math.MaxUint64
	}
	return gas.Uint64()
}

func (c *bigModExp) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	var (
		baseLen = new(big.Int).SetBytes(getData(input, 0, 32)).Uint64()
		expLen  = new(big.Int).SetBytes(getData(input, 32, 32)).Uint64()
		modLen  = new(big.Int).SetBytes(getData(input, 64, 32)).Uint64()
	)
	if len(input) > 96 {
		input = input[96:]
	} else {
		input = input[:0]
	}
	// Handle a special case when both the base and mod length is zero
	if baseLen == 0 && modLen == 0 {
		return []byte{}, nil
	}
	// Retrieve the operands and execute the exponentiation
	var (
		base = new(big.Int).SetBytes(getData(input, 0, baseLen))
		exp  = new(big.Int).SetBytes(getData(input, baseLen, expLen))
		mod  = new(big.Int).SetBytes(getData(input, baseLen+expLen, modLen))
	)
	if mod.BitLen() == 0 {
		// Modulo 0 is undefined, return zero
		return common.LeftPadBytes([]byte{}, int(modLen)), nil
	}
	return common.LeftPadBytes(base.Exp(base, exp, mod).Bytes(), int(modLen)), nil
}

// newCurvePoint unmarshals a binary blob into a bn256 elliptic curve point,
// returning it, or an error if the point is invalid.
func newCurvePoint(blob []byte) (*bn256.G1, error) {
	p := new(bn256.G1)
	if _, err := p.Unmarshal(blob); err != nil {
		return nil, err
	}
	return p, nil
}

// newTwistPoint unmarshals a binary blob into a bn256 elliptic curve point,
// returning it, or an error if the point is invalid.
func newTwistPoint(blob []byte) (*bn256.G2, error) {
	p := new(bn256.G2)
	if _, err := p.Unmarshal(blob); err != nil {
		return nil, err
	}
	return p, nil
}

// runBn256Add implements the Bn256Add precompile, referenced by both
// Byzantium and Istanbul operations.
func runBn256Add(input []byte) ([]byte, error) {
	x, err := newCurvePoint(getData(input, 0, 64))
	if err != nil {
		return nil, err
	}
	y, err := newCurvePoint(getData(input, 64, 64))
	if err != nil {
		return nil, err
	}
	res := new(bn256.G1)
	res.Add(x, y)
	return res.Marshal(), nil
}

// bn256Add implements a native elliptic curve point addition conforming to
// Istanbul consensus rules.
type bn256AddIstanbul struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bn256AddIstanbul) RequiredGas(input []byte) uint64 {
	return params.Bn256AddGasIstanbul
}

func (c *bn256AddIstanbul) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	return runBn256Add(input)
}

// bn256AddByzantium implements a native elliptic curve point addition
// conforming to Byzantium consensus rules.
type bn256AddByzantium struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bn256AddByzantium) RequiredGas(input []byte) uint64 {
	return params.Bn256AddGasByzantium
}

func (c *bn256AddByzantium) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	return runBn256Add(input)
}

// runBn256ScalarMul implements the Bn256ScalarMul precompile, referenced by
// both Byzantium and Istanbul operations.
func runBn256ScalarMul(input []byte) ([]byte, error) {
	p, err := newCurvePoint(getData(input, 0, 64))
	if err != nil {
		return nil, err
	}
	res := new(bn256.G1)
	res.ScalarMult(p, new(big.Int).SetBytes(getData(input, 64, 32)))
	return res.Marshal(), nil
}

// bn256ScalarMulIstanbul implements a native elliptic curve scalar
// multiplication conforming to Istanbul consensus rules.
type bn256ScalarMulIstanbul struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bn256ScalarMulIstanbul) RequiredGas(input []byte) uint64 {
	return params.Bn256ScalarMulGasIstanbul
}

func (c *bn256ScalarMulIstanbul) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	return runBn256ScalarMul(input)
}

// bn256ScalarMulByzantium implements a native elliptic curve scalar
// multiplication conforming to Byzantium consensus rules.
type bn256ScalarMulByzantium struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bn256ScalarMulByzantium) RequiredGas(input []byte) uint64 {
	return params.Bn256ScalarMulGasByzantium
}

func (c *bn256ScalarMulByzantium) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	return runBn256ScalarMul(input)
}

var (
	// true32Byte is returned if the bn256 pairing check succeeds.
	true32Byte = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}

	// false32Byte is returned if the bn256 pairing check fails.
	false32Byte = make([]byte, 32)

	// errBadPairingInput is returned if the bn256 pairing input is invalid.
	errBadPairingInput = errors.New("bad elliptic curve pairing size")
)

// runBn256Pairing implements the Bn256Pairing precompile, referenced by both
// Byzantium and Istanbul operations.
func runBn256Pairing(input []byte) ([]byte, error) {
	// Handle some corner cases cheaply
	if len(input)%192 > 0 {
		return nil, errBadPairingInput
	}
	// Convert the input into a set of coordinates
	var (
		cs []*bn256.G1
		ts []*bn256.G2
	)
	for i := 0; i < len(input); i += 192 {
		c, err := newCurvePoint(input[i : i+64])
		if err != nil {
			return nil, err
		}
		t, err := newTwistPoint(input[i+64 : i+192])
		if err != nil {
			return nil, err
		}
		cs = append(cs, c)
		ts = append(ts, t)
	}
	// Execute the pairing checks and return the results
	if bn256.PairingCheck(cs, ts) {
		return true32Byte, nil
	}
	return false32Byte, nil
}

// bn256PairingIstanbul implements a pairing pre-compile for the bn256 curve
// conforming to Istanbul consensus rules.
type bn256PairingIstanbul struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bn256PairingIstanbul) RequiredGas(input []byte) uint64 {
	return params.Bn256PairingBaseGasIstanbul + uint64(len(input)/192)*params.Bn256PairingPerPointGasIstanbul
}

func (c *bn256PairingIstanbul) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	return runBn256Pairing(input)
}

// bn256PairingByzantium implements a pairing pre-compile for the bn256 curve
// conforming to Byzantium consensus rules.
type bn256PairingByzantium struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bn256PairingByzantium) RequiredGas(input []byte) uint64 {
	return params.Bn256PairingBaseGasByzantium + uint64(len(input)/192)*params.Bn256PairingPerPointGasByzantium
}

func (c *bn256PairingByzantium) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	return runBn256Pairing(input)
}

type blake2F struct{}

func (c *blake2F) RequiredGas(input []byte) uint64 {
	// If the input is malformed, we can't calculate the gas, return 0 and let the
	// actual call choke and fault.
	if len(input) != blake2FInputLength {
		return 0
	}
	return uint64(binary.BigEndian.Uint32(input[0:4]))
}

const (
	blake2FInputLength        = 213
	blake2FFinalBlockBytes    = byte(1)
	blake2FNonFinalBlockBytes = byte(0)
)

var (
	errBlake2FInvalidInputLength = errors.New("invalid input length")
	errBlake2FInvalidFinalFlag   = errors.New("invalid final flag")
)

func (c *blake2F) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	// Make sure the input is valid (correct length and final flag)
	if len(input) != blake2FInputLength {
		return nil, errBlake2FInvalidInputLength
	}
	if input[212] != blake2FNonFinalBlockBytes && input[212] != blake2FFinalBlockBytes {
		return nil, errBlake2FInvalidFinalFlag
	}
	// Parse the input into the Blake2b call parameters
	var (
		rounds = binary.BigEndian.Uint32(input[0:4])
		final  = (input[212] == blake2FFinalBlockBytes)

		h [8]uint64
		m [16]uint64
		t [2]uint64
	)
	for i := 0; i < 8; i++ {
		offset := 4 + i*8
		h[i] = binary.LittleEndian.Uint64(input[offset : offset+8])
	}
	for i := 0; i < 16; i++ {
		offset := 68 + i*8
		m[i] = binary.LittleEndian.Uint64(input[offset : offset+8])
	}
	t[0] = binary.LittleEndian.Uint64(input[196:204])
	t[1] = binary.LittleEndian.Uint64(input[204:212])

	// Execute the compression function, extract and return the result
	blake2b.F(&h, m, t, final, rounds)

	output := make([]byte, 64)
	for i := 0; i < 8; i++ {
		offset := i * 8
		binary.LittleEndian.PutUint64(output[offset:offset+8], h[i])
	}
	return output, nil
}

var (
	errBLS12381InvalidInputLength          = errors.New("invalid input length")
	errBLS12381InvalidFieldElementTopBytes = errors.New("invalid field element top bytes")
	errBLS12381G1PointSubgroup             = errors.New("g1 point is not on correct subgroup")
	errBLS12381G2PointSubgroup             = errors.New("g2 point is not on correct subgroup")
)

// bls12381G1Add implements EIP-2537 G1Add precompile.
type bls12381G1Add struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bls12381G1Add) RequiredGas(input []byte) uint64 {
	return params.Bls12381G1AddGas
}

func (c *bls12381G1Add) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	// Implements EIP-2537 G1Add precompile.
	// > G1 addition call expects `256` bytes as an input that is interpreted as byte concatenation of two G1 points (`128` bytes each).
	// > Output is an encoding of addition operation result - single G1 point (`128` bytes).
	if len(input) != 256 {
		return nil, errBLS12381InvalidInputLength
	}
	var err error
	var p0, p1 *bls12381.PointG1

	// Initialize G1
	g := bls12381.NewG1()

	// Decode G1 point p_0
	if p0, err = g.DecodePoint(input[:128]); err != nil {
		return nil, err
	}
	// Decode G1 point p_1
	if p1, err = g.DecodePoint(input[128:]); err != nil {
		return nil, err
	}

	// Compute r = p_0 + p_1
	r := g.New()
	g.Add(r, p0, p1)

	// Encode the G1 point result into 128 bytes
	return g.EncodePoint(r), nil
}

// bls12381G1Mul implements EIP-2537 G1Mul precompile.
type bls12381G1Mul struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bls12381G1Mul) RequiredGas(input []byte) uint64 {
	return params.Bls12381G1MulGas
}

func (c *bls12381G1Mul) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	// Implements EIP-2537 G1Mul precompile.
	// > G1 multiplication call expects `160` bytes as an input that is interpreted as byte concatenation of encoding of G1 point (`128` bytes) and encoding of a scalar value (`32` bytes).
	// > Output is an encoding of multiplication operation result - single G1 point (`128` bytes).
	if len(input) != 160 {
		return nil, errBLS12381InvalidInputLength
	}
	var err error
	var p0 *bls12381.PointG1

	// Initialize G1
	g := bls12381.NewG1()

	// Decode G1 point
	if p0, err = g.DecodePoint(input[:128]); err != nil {
		return nil, err
	}
	// Decode scalar value
	e := new(big.Int).SetBytes(input[128:])

	// Compute r = e * p_0
	r := g.New()
	g.MulScalar(r, p0, e)

	// Encode the G1 point into 128 bytes
	return g.EncodePoint(r), nil
}

// bls12381G1MultiExp implements EIP-2537 G1MultiExp precompile.
type bls12381G1MultiExp struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bls12381G1MultiExp) RequiredGas(input []byte) uint64 {
	// Calculate G1 point, scalar value pair length
	k := len(input) / 160
	if k == 0 {
		// Return 0 gas for small input length
		return 0
	}
	// Lookup discount value for G1 point, scalar value pair length
	var discount uint64
	if dLen := len(params.Bls12381MultiExpDiscountTable); k < dLen {
		discount = params.Bls12381MultiExpDiscountTable[k-1]
	} else {
		discount = params.Bls12381MultiExpDiscountTable[dLen-1]
	}
	// Calculate gas and return the result
	return (uint64(k) * params.Bls12381G1MulGas * discount) / 1000
}

func (c *bls12381G1MultiExp) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	// Implements EIP-2537 G1MultiExp precompile.
	// G1 multiplication call expects `160*k` bytes as an input that is interpreted as byte concatenation of `k` slices each of them being a byte concatenation of encoding of G1 point (`128` bytes) and encoding of a scalar value (`32` bytes).
	// Output is an encoding of multiexponentiation operation result - single G1 point (`128` bytes).
	k := len(input) / 160
	if len(input) == 0 || len(input)%160 != 0 {
		return nil, errBLS12381InvalidInputLength
	}
	var err error
	points := make([]*bls12381.PointG1, k)
	scalars := make([]*big.Int, k)

	// Initialize G1
	g := bls12381.NewG1()

	// Decode point scalar pairs
	for i := 0; i < k; i++ {
		off := 160 * i
		t0, t1, t2 := off, off+128, off+160
		// Decode G1 point
		if points[i], err = g.DecodePoint(input[t0:t1]); err != nil {
			return nil, err
		}
		// Decode scalar value
		scalars[i] = new(big.Int).SetBytes(input[t1:t2])
	}

	// Compute r = e_0 * p_0 + e_1 * p_1 + ... + e_(k-1) * p_(k-1)
	r := g.New()
	g.MultiExp(r, points, scalars)

	// Encode the G1 point to 128 bytes
	return g.EncodePoint(r), nil
}

// bls12381G2Add implements EIP-2537 G2Add precompile.
type bls12381G2Add struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bls12381G2Add) RequiredGas(input []byte) uint64 {
	return params.Bls12381G2AddGas
}

func (c *bls12381G2Add) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	// Implements EIP-2537 G2Add precompile.
	// > G2 addition call expects `512` bytes as an input that is interpreted as byte concatenation of two G2 points (`256` bytes each).
	// > Output is an encoding of addition operation result - single G2 point (`256` bytes).
	if len(input) != 512 {
		return nil, errBLS12381InvalidInputLength
	}
	var err error
	var p0, p1 *bls12381.PointG2

	// Initialize G2
	g := bls12381.NewG2()
	r := g.New()

	// Decode G2 point p_0
	if p0, err = g.DecodePoint(input[:256]); err != nil {
		return nil, err
	}
	// Decode G2 point p_1
	if p1, err = g.DecodePoint(input[256:]); err != nil {
		return nil, err
	}

	// Compute r = p_0 + p_1
	g.Add(r, p0, p1)

	// Encode the G2 point into 256 bytes
	return g.EncodePoint(r), nil
}

// bls12381G2Mul implements EIP-2537 G2Mul precompile.
type bls12381G2Mul struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bls12381G2Mul) RequiredGas(input []byte) uint64 {
	return params.Bls12381G2MulGas
}

func (c *bls12381G2Mul) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	// Implements EIP-2537 G2MUL precompile logic.
	// > G2 multiplication call expects `288` bytes as an input that is interpreted as byte concatenation of encoding of G2 point (`256` bytes) and encoding of a scalar value (`32` bytes).
	// > Output is an encoding of multiplication operation result - single G2 point (`256` bytes).
	if len(input) != 288 {
		return nil, errBLS12381InvalidInputLength
	}
	var err error
	var p0 *bls12381.PointG2

	// Initialize G2
	g := bls12381.NewG2()

	// Decode G2 point
	if p0, err = g.DecodePoint(input[:256]); err != nil {
		return nil, err
	}
	// Decode scalar value
	e := new(big.Int).SetBytes(input[256:])

	// Compute r = e * p_0
	r := g.New()
	g.MulScalar(r, p0, e)

	// Encode the G2 point into 256 bytes
	return g.EncodePoint(r), nil
}

// bls12381G2MultiExp implements EIP-2537 G2MultiExp precompile.
type bls12381G2MultiExp struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bls12381G2MultiExp) RequiredGas(input []byte) uint64 {
	// Calculate G2 point, scalar value pair length
	k := len(input) / 288
	if k == 0 {
		// Return 0 gas for small input length
		return 0
	}
	// Lookup discount value for G2 point, scalar value pair length
	var discount uint64
	if dLen := len(params.Bls12381MultiExpDiscountTable); k < dLen {
		discount = params.Bls12381MultiExpDiscountTable[k-1]
	} else {
		discount = params.Bls12381MultiExpDiscountTable[dLen-1]
	}
	// Calculate gas and return the result
	return (uint64(k) * params.Bls12381G2MulGas * discount) / 1000
}

func (c *bls12381G2MultiExp) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	// Implements EIP-2537 G2MultiExp precompile logic
	// > G2 multiplication call expects `288*k` bytes as an input that is interpreted as byte concatenation of `k` slices each of them being a byte concatenation of encoding of G2 point (`256` bytes) and encoding of a scalar value (`32` bytes).
	// > Output is an encoding of multiexponentiation operation result - single G2 point (`256` bytes).
	k := len(input) / 288
	if len(input) == 0 || len(input)%288 != 0 {
		return nil, errBLS12381InvalidInputLength
	}
	var err error
	points := make([]*bls12381.PointG2, k)
	scalars := make([]*big.Int, k)

	// Initialize G2
	g := bls12381.NewG2()

	// Decode point scalar pairs
	for i := 0; i < k; i++ {
		off := 288 * i
		t0, t1, t2 := off, off+256, off+288
		// Decode G1 point
		if points[i], err = g.DecodePoint(input[t0:t1]); err != nil {
			return nil, err
		}
		// Decode scalar value
		scalars[i] = new(big.Int).SetBytes(input[t1:t2])
	}

	// Compute r = e_0 * p_0 + e_1 * p_1 + ... + e_(k-1) * p_(k-1)
	r := g.New()
	g.MultiExp(r, points, scalars)

	// Encode the G2 point to 256 bytes.
	return g.EncodePoint(r), nil
}

// bls12381Pairing implements EIP-2537 Pairing precompile.
type bls12381Pairing struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bls12381Pairing) RequiredGas(input []byte) uint64 {
	return params.Bls12381PairingBaseGas + uint64(len(input)/384)*params.Bls12381PairingPerPairGas
}

func (c *bls12381Pairing) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	// Implements EIP-2537 Pairing precompile logic.
	// > Pairing call expects `384*k` bytes as an inputs that is interpreted as byte concatenation of `k` slices. Each slice has the following structure:
	// > - `128` bytes of G1 point encoding
	// > - `256` bytes of G2 point encoding
	// > Output is a `32` bytes where last single byte is `0x01` if pairing result is equal to multiplicative identity in a pairing target field and `0x00` otherwise
	// > (which is equivalent of Big Endian encoding of Solidity values `uint256(1)` and `uin256(0)` respectively).
	k := len(input) / 384
	if len(input) == 0 || len(input)%384 != 0 {
		return nil, errBLS12381InvalidInputLength
	}

	// Initialize BLS12-381 pairing engine
	e := bls12381.NewPairingEngine()
	g1, g2 := e.G1, e.G2

	// Decode pairs
	for i := 0; i < k; i++ {
		off := 384 * i
		t0, t1, t2 := off, off+128, off+384

		// Decode G1 point
		p1, err := g1.DecodePoint(input[t0:t1])
		if err != nil {
			return nil, err
		}
		// Decode G2 point
		p2, err := g2.DecodePoint(input[t1:t2])
		if err != nil {
			return nil, err
		}

		// 'point is on curve' check already done,
		// Here we need to apply subgroup checks.
		if !g1.InCorrectSubgroup(p1) {
			return nil, errBLS12381G1PointSubgroup
		}
		if !g2.InCorrectSubgroup(p2) {
			return nil, errBLS12381G2PointSubgroup
		}

		// Update pairing engine with G1 and G2 ponits
		e.AddPair(p1, p2)
	}
	// Prepare 32 byte output
	out := make([]byte, 32)

	// Compute pairing and set the result
	if e.Check() {
		out[31] = 1
	}
	return out, nil
}

// decodeBLS12381FieldElement decodes BLS12-381 elliptic curve field element.
// Removes top 16 bytes of 64 byte input.
func decodeBLS12381FieldElement(in []byte) ([]byte, error) {
	if len(in) != 64 {
		return nil, errors.New("invalid field element length")
	}
	// check top bytes
	for i := 0; i < 16; i++ {
		if in[i] != byte(0x00) {
			return nil, errBLS12381InvalidFieldElementTopBytes
		}
	}
	out := make([]byte, 48)
	copy(out[:], in[16:])
	return out, nil
}

// bls12381MapG1 implements EIP-2537 MapG1 precompile.
type bls12381MapG1 struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bls12381MapG1) RequiredGas(input []byte) uint64 {
	return params.Bls12381MapG1Gas
}

func (c *bls12381MapG1) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	// Implements EIP-2537 Map_To_G1 precompile.
	// > Field-to-curve call expects `64` bytes an an input that is interpreted as a an element of the base field.
	// > Output of this call is `128` bytes and is G1 point following respective encoding rules.
	if len(input) != 64 {
		return nil, errBLS12381InvalidInputLength
	}

	// Decode input field element
	fe, err := decodeBLS12381FieldElement(input)
	if err != nil {
		return nil, err
	}

	// Initialize G1
	g := bls12381.NewG1()

	// Compute mapping
	r, err := g.MapToCurve(fe)
	if err != nil {
		return nil, err
	}

	// Encode the G1 point to 128 bytes
	return g.EncodePoint(r), nil
}

// bls12381MapG2 implements EIP-2537 MapG2 precompile.
type bls12381MapG2 struct{}

// RequiredGas returns the gas required to execute the pre-compiled contract.
func (c *bls12381MapG2) RequiredGas(input []byte) uint64 {
	return params.Bls12381MapG2Gas
}

func (c *bls12381MapG2) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	// Implements EIP-2537 Map_FP2_TO_G2 precompile logic.
	// > Field-to-curve call expects `128` bytes an an input that is interpreted as a an element of the quadratic extension field.
	// > Output of this call is `256` bytes and is G2 point following respective encoding rules.
	if len(input) != 128 {
		return nil, errBLS12381InvalidInputLength
	}

	// Decode input field element
	fe := make([]byte, 96)
	c0, err := decodeBLS12381FieldElement(input[:64])
	if err != nil {
		return nil, err
	}
	copy(fe[48:], c0)
	c1, err := decodeBLS12381FieldElement(input[64:])
	if err != nil {
		return nil, err
	}
	copy(fe[:48], c1)

	// Initialize G2
	g := bls12381.NewG2()

	// Compute mapping
	r, err := g.MapToCurve(fe)
	if err != nil {
		return nil, err
	}

	// Encode the G2 point to 256 bytes
	return g.EncodePoint(r), nil
}

// checkEnode implemented as a native contract.
type checkEnode struct{}

func (c checkEnode) RequiredGas(_ []byte) uint64 {
	return params.AutonityEnodeCheckGas
}
func (c checkEnode) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	if len(input) == 0 {
		return nil, fmt.Errorf("invalid enode - empty")
	}
	out := make([]byte, 64)
	nodeStr := string(input)

	node, err := enode.ParseV4NoResolve(nodeStr)
	if err != nil {
		copy(out[32:], true32Byte)
		return out, nil
	}

	address := crypto.PubkeyToAddress(*node.Pubkey())
	copy(out, address.Bytes())
	copy(out[32:], false32Byte)
	return out, nil
}

func readCommittee(db StateDB, caller common.Address, committeeSlot common.Hash) *types.Committee {
	committeeSize := int(db.GetState(caller, committeeSlot).Big().Uint64())
	members := make([]types.CommitteeMember, committeeSize)

	committeeOffset := crypto.Keccak256Hash(committeeSlot.Bytes())
	for i := 0; i < committeeSize; i++ {
		nodeAddress := common.BytesToAddress(db.GetState(caller, committeeOffset).Bytes())
		committeeOffset = common.BytesToHash(new(big.Int).Add(committeeOffset.Big(), common.Big1).Bytes())
		votingPower := db.GetState(caller, committeeOffset).Big()
		committeeOffset = common.BytesToHash(new(big.Int).Add(committeeOffset.Big(), common.Big1).Bytes())
		// the reading of the consensus key assumes that the key is 48 bytes long. This will break if the consensus key changes length.
		consensusKeySlot := crypto.Keccak256Hash(committeeOffset.Bytes())
		consensusKeyBytes1 := db.GetState(caller, consensusKeySlot).Bytes()
		consensusKeySlot = common.BytesToHash(new(big.Int).Add(consensusKeySlot.Big(), common.Big1).Bytes())
		consensusKeyBytes2 := db.GetState(caller, consensusKeySlot).Bytes()
		consensusKeyBytes := append(consensusKeyBytes1, consensusKeyBytes2[:blst.BLSPubkeyLength-DataLen]...)
		committeeOffset = common.BytesToHash(new(big.Int).Add(committeeOffset.Big(), common.Big1).Bytes())

		members[i] = types.CommitteeMember{
			Address:           nodeAddress,
			VotingPower:       votingPower,
			ConsensusKeyBytes: consensusKeyBytes,
		}
	}

	committee := &types.Committee{Members: members}
	err := committee.Enrich()
	if err != nil {
		panic("cannot unmarshal bls public keys from committee members: " + err.Error())
	}
	return committee
}

type absenteesComputer struct{}

func (c absenteesComputer) RequiredGas(_ []byte) uint64 {
	return params.AbsenteesComputerGas
}

func (c absenteesComputer) Run(input []byte, blockNumber uint64, evm *EVM, caller common.Address) ([]byte, error) {
	// if we are in testMode (used by truffle tests) just return no absents and zero effort
	if evm.chainConfig.TestMode {
		return makeReturnData(false, common.Big0, []common.Address{}), nil
	}

	if caller != params.OmissionAccountabilityContractAddress {
		return nil, errUnauthorized
	}

	// input is always one packed boolean (1 byte) + 2 uint256 (32 bytes each)
	if len(input) != 1+DataLen+DataLen {
		// TODO: should we panic here? incorrect input --> we have a programming error.
		// 	However other precompiles deal with it this way
		return nil, errBadInput
	}
	if !(input[0] == byte(0) || input[0] == byte(1)) {
		return nil, errBadInput
	}
	mustBeEmpty := input[0] == byte(1)
	delta := new(big.Int).SetBytes(input[1:33])
	committeeSlot := common.BytesToHash(input[33:])

	proof := evm.Context.ActivityProof
	targetRound := evm.Context.ActivityProofRound

	// during the first delta blocks of the epoch, the proof should be empty. If not, reject proposal
	if mustBeEmpty {
		if proof != nil {
			return nil, errNonEmptyProof
		}
		return makeReturnData(false, new(big.Int), []common.Address{}), nil
	}

	// at this point the proof should not be empty and should contain at least quorum voting power, otherwise the proposer is faulty
	if proof == nil {
		return makeReturnData(true, new(big.Int), []common.Address{}), nil
	}

	targetHeight := blockNumber - delta.Uint64()
	targetHash := evm.Context.GetHash(targetHeight)
	headerSeal := message.PrepareCommittedSeal(targetHash, int64(targetRound), new(big.Int).SetUint64(targetHeight))

	committee := readCommittee(evm.StateDB, caller, committeeSlot)
	signers, power, err := proof.Validate(headerSeal, committee, true)
	if err != nil {
		// it should never happen that we cannot aggregate public keys fetched from state
		if errors.Is(err, types.ErrNonAggregatablePublicKeys) {
			panic("cannot aggregate keys fetched from state: " + err.Error())
		}
		return nil, fmt.Errorf("invalid activity proof: %w", err)
	}

	proposerEffort := new(big.Int).Set(power)
	proposerEffort.Sub(proposerEffort, bft.Quorum(committee.TotalVotingPower()))

	absentees := deriveAbsentees(signers, committee)
	return makeReturnData(false, proposerEffort, absentees), nil
}

func makeReturnData(isProposerFaulty bool, proposerEffort *big.Int, absentees []common.Address) []byte {
	// do not pack the bool to make decoding easier in precompiled.sol
	length := DataLen + DataLen + DataLen + DataLen // 1 bool + 1 uint256 + the offset of the dynamic addresses array + the length of the dynamic addresses array

	out := make([]byte, length)
	if isProposerFaulty {
		copy(out[0:DataLen], common.LeftPadBytes([]byte{1}, DataLen))
	} else {
		copy(out[0:DataLen], common.LeftPadBytes([]byte{0}, DataLen))
	}
	copy(out[DataLen:DataLen*2], common.LeftPadBytes(proposerEffort.Bytes(), DataLen))

	copy(out[DataLen*2:DataLen*3], common.LeftPadBytes(new(big.Int).SetUint64(DataLen*3).Bytes(), DataLen))              // offset
	copy(out[DataLen*3:DataLen*4], common.LeftPadBytes(new(big.Int).SetUint64(uint64(len(absentees))).Bytes(), DataLen)) // length

	for _, absentee := range absentees {
		out = append(out, common.LeftPadBytes(absentee.Bytes(), DataLen)...)
	}

	return out
}

func deriveAbsentees(signers map[common.Address]struct{}, committee *types.Committee) []common.Address {
	var absentees []common.Address
	for _, member := range committee.Members {
		_, found := signers[member.Address]
		if !found {
			absentees = append(absentees, member.Address)
		}
	}
	return absentees
}

// POPVerifier verifies the proof of possession of consensus key.
type POPVerifier struct{}

func (b *POPVerifier) RequiredGas(_ []byte) uint64 {
	return params.POPVerifierGas
}

func (b *POPVerifier) Run(input []byte, _ uint64, _ *EVM, _ common.Address) ([]byte, error) {
	totalBytes := ArrayLenBytes + POPBytes
	if len(input) != totalBytes {
		return failure32Byte, fmt.Errorf("invalid proof - empty")
	}

	signatureOffset := ArrayLenBytes + blst.BLSPubkeyLength
	treasuryOffset := signatureOffset + blst.BLSSignatureLength
	keyBytes := input[ArrayLenBytes:signatureOffset]
	sigBytes := input[signatureOffset:treasuryOffset]
	treasuryBytes := input[treasuryOffset:]

	key, err := blst.PublicKeyFromBytes(keyBytes)
	if err != nil {
		return failure32Byte, err
	}
	sig, err := blst.SignatureFromBytes(sigBytes)
	if err != nil {
		return failure32Byte, err
	}

	if sig.IsZero() {
		return failure32Byte, crypto.ErrorInvalidPOP
	}

	err = crypto.BLSPOPVerify(key, sig, treasuryBytes)
	if err != nil {
		return failure32Byte, err
	}
	return successResult, nil
}
