hermez-node/eth/rollup.go

package eth

import (
	"context"
	"fmt"
	"math/big"
	"strings"

	"github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/accounts/abi"
	"github.com/ethereum/go-ethereum/accounts/abi/bind"
	ethCommon "github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/ethclient"
	"github.com/hermeznetwork/hermez-node/common"
	ERC777 "github.com/hermeznetwork/hermez-node/eth/contracts/erc777"
	Hermez "github.com/hermeznetwork/hermez-node/eth/contracts/hermez"
	"github.com/hermeznetwork/hermez-node/log"
	"github.com/iden3/go-iden3-crypto/babyjub"
	"golang.org/x/crypto/sha3"
)

const (
	// RollupConstMaxFeeIdxCoordinator is the maximum number of tokens the
	// coordinator can use to collect fees (determines the number of tokens
	// that the coordinator can collect fees from).  This value is
	// determined by the circuit.
	RollupConstMaxFeeIdxCoordinator = 64
	// RollupConstReservedIDx First 256 indexes reserved, first user index will be the 256
	RollupConstReservedIDx = 255
	// RollupConstExitIDx IDX 1 is reserved for exits
	RollupConstExitIDx = 1
	// RollupConstLimitLoadAmount Max load amount allowed (loadAmount: L1 --> L2)
	RollupConstLimitLoadAmount = (1 << 128)
	// RollupConstLimitL2TransferAmount Max amount allowed (amount L2 --> L2)
	RollupConstLimitL2TransferAmount = (1 << 192)
	// RollupConstLimitTokens Max number of tokens allowed to be registered inside the rollup
	RollupConstLimitTokens = (1 << 32)
	// RollupConstL1CoordinatorTotalBytes [4 bytes] token + [32 bytes] babyjub + [65 bytes] compressedSignature
	RollupConstL1CoordinatorTotalBytes = 101
	// RollupConstL1UserTotalBytes [20 bytes] fromEthAddr + [32 bytes] fromBjj-compressed + [6 bytes] fromIdx +
	// [2 bytes] loadAmountFloat16 + [2 bytes] amountFloat16 + [4 bytes] tokenId + [6 bytes] toIdx
	RollupConstL1UserTotalBytes = 72
	// RollupConstMaxL1UserTx Maximum L1-user transactions allowed to be queued in a batch
	RollupConstMaxL1UserTx = 128
	// RollupConstMaxL1Tx Maximum L1 transactions allowed to be queued in a batch
	RollupConstMaxL1Tx = 256
	// RollupConstInputSHAConstantBytes [6 bytes] lastIdx + [6 bytes] newLastIdx  + [32 bytes] stateRoot  + [32 bytes] newStRoot  + [32 bytes] newExitRoot +
	// [_MAX_L1_TX * _L1_USER_TOTALBYTES bytes] l1TxsData + totalL2TxsDataLength + feeIdxCoordinatorLength + [2 bytes] chainID =
	// 18542 bytes +  totalL2TxsDataLength + feeIdxCoordinatorLength
	RollupConstInputSHAConstantBytes = 18542
	// RollupConstNumBuckets Number of buckets
	RollupConstNumBuckets = 5
	// RollupConstMaxWithdrawalDelay max withdrawal delay in seconds
	RollupConstMaxWithdrawalDelay = 2 * 7 * 24 * 60 * 60
	// RollupConstExchangeMultiplier exchange multiplier
	RollupConstExchangeMultiplier = 1e14
	// LenVerifiers number of Rollup Smart Contract Verifiers
	LenVerifiers = 1
)

var (
	// RollupConstEthAddressInternalOnly This ethereum address is used internally for rollup accounts that don't have ethereum address, only Babyjubjub
	// This non-ethereum accounts can be created by the coordinator and allow users to have a rollup
	// account without needing an ethereum address
	RollupConstEthAddressInternalOnly = ethCommon.HexToAddress("0xFFfFfFffFFfffFFfFFfFFFFFffFFFffffFfFFFfF")
	// RollupConstRfield Modulus zkSNARK
	RollupConstRfield, _ = new(big.Int).SetString(
		"21888242871839275222246405745257275088548364400416034343698204186575808495617", 10)

	// RollupConstERC1820 ERC1820Registry address
	RollupConstERC1820 = ethCommon.HexToAddress("0x1820a4B7618BdE71Dce8cdc73aAB6C95905faD24")

	// ERC777 tokens signatures

	// RollupConstRecipientInterfaceHash ERC777 recipient interface hash
	RollupConstRecipientInterfaceHash = crypto.Keccak256([]byte("ERC777TokensRecipient"))
	// RollupConstPerformL1UserTxSignature the signature of the function that can be called thru an ERC777 `send`
	RollupConstPerformL1UserTxSignature = crypto.Keccak256([]byte("addL1Transaction(uint256,uint48,uint16,uint16,uint32,uint48)"))
	// RollupConstAddTokenSignature the signature of the function that can be called thru an ERC777 `send`
	RollupConstAddTokenSignature = crypto.Keccak256([]byte("addToken(address)"))
	// RollupConstSendSignature ERC777 Signature
	RollupConstSendSignature = crypto.Keccak256([]byte("send(address,uint256,bytes)"))
	// RollupConstERC777Granularity ERC777 Signature
	RollupConstERC777Granularity = crypto.Keccak256([]byte("granularity()"))
	// RollupConstWithdrawalDelayerDeposit  This constant are used to deposit tokens from ERC77 tokens into withdrawal delayer
	RollupConstWithdrawalDelayerDeposit = crypto.Keccak256([]byte("deposit(address,address,uint192)"))

	// ERC20 signature

	// RollupConstTransferSignature This constant is used in the _safeTransfer internal method in order to safe GAS.
	RollupConstTransferSignature = crypto.Keccak256([]byte("transfer(address,uint256)"))
	// RollupConstTransferFromSignature This constant is used in the _safeTransfer internal method in order to safe GAS.
	RollupConstTransferFromSignature = crypto.Keccak256([]byte("transferFrom(address,address,uint256)"))
	// RollupConstApproveSignature This constant is used in the _safeTransfer internal method in order to safe GAS.
	RollupConstApproveSignature = crypto.Keccak256([]byte("approve(address,uint256)"))
	// RollupConstERC20Signature ERC20 decimals signature
	RollupConstERC20Signature = crypto.Keccak256([]byte("decimals()"))
)

// RollupPublicConstants are the constants of the Rollup Smart Contract
type RollupPublicConstants struct {
	AbsoluteMaxL1L2BatchTimeout int64                  `json:"absoluteMaxL1L2BatchTimeout"`
	TokenHEZ                    ethCommon.Address      `json:"tokenHEZ"`
	Verifiers                   []RollupVerifierStruct `json:"verifiers"`
	HermezAuctionContract       ethCommon.Address      `json:"hermezAuctionContract"`
	HermezGovernanceDAOAddress  ethCommon.Address      `json:"hermezGovernanceDAOAddress"`
	SafetyAddress               ethCommon.Address      `json:"safetyAddress"`
	WithdrawDelayerContract     ethCommon.Address      `json:"withdrawDelayerContract"`
}

// Bucket are the variables of each Bucket of Rollup Smart Contract
type Bucket struct {
	CeilUSD             uint64 `json:"ceilUSD"`
	BlockStamp          uint64 `json:"blockStamp"`
	Withdrawals         uint64 `json:"withdrawals"`
	BlockWithdrawalRate uint64 `json:"blockWithdrawalRate"`
	MaxWithdrawals      uint64 `json:"maxWithdrawals"`
}

// RollupVariables are the variables of the Rollup Smart Contract
type RollupVariables struct {
	FeeAddToken           *big.Int                      `json:"feeAddToken" meddler:"fee_addtoken"`
	ForgeL1L2BatchTimeout int64                         `json:"forgeL1L2BatchTimeout" meddler:"forge_l1l2_timeout"`
	WithdrawalDelay       uint64                        `json:"withdrawalDelay" meddler:"withdrawal_delay"`
	Buckets               [RollupConstNumBuckets]Bucket `json:"buckets" meddler:"buckets,json"`
}

// QueueStruct is the queue of L1Txs for a batch
type QueueStruct struct {
	L1TxQueue    []common.L1Tx
	TotalL1TxFee *big.Int
}

// NewQueueStruct creates a new clear QueueStruct.
func NewQueueStruct() *QueueStruct {
	return &QueueStruct{
		L1TxQueue:    make([]common.L1Tx, 0),
		TotalL1TxFee: big.NewInt(0),
	}
}

// RollupVerifierStruct is the information about verifiers of the Rollup Smart Contract
type RollupVerifierStruct struct {
	MaxTx   int64 `json:"maxTx"`
	NLevels int64 `json:"nlevels"`
}

// RollupState represents the state of the Rollup in the Smart Contract
type RollupState struct {
	StateRoot              *big.Int
	ExitRoots              []*big.Int
	ExitNullifierMap       map[[256 / 8]byte]bool
	TokenList              []ethCommon.Address
	TokenMap               map[ethCommon.Address]bool
	MapL1TxQueue           map[int64]*QueueStruct
	LastL1L2Batch          int64
	CurrentToForgeL1TxsNum int64
	LastToForgeL1TxsNum    int64
	CurrentIdx             int64
}

// RollupEventL1UserTx is an event of the Rollup Smart Contract
type RollupEventL1UserTx struct {
	// ToForgeL1TxsNum int64 // QueueIndex       *big.Int
	// Position        int   // TransactionIndex *big.Int
	L1UserTx common.L1Tx
}

// RollupEventL1UserTxAux is an event of the Rollup Smart Contract
type RollupEventL1UserTxAux struct {
	ToForgeL1TxsNum uint64 // QueueIndex       *big.Int
	Position        uint8  // TransactionIndex *big.Int
	L1UserTx        []byte
}

// RollupEventAddToken is an event of the Rollup Smart Contract
type RollupEventAddToken struct {
	TokenAddress ethCommon.Address
	TokenID      uint32
}

// RollupEventForgeBatch is an event of the Rollup Smart Contract
type RollupEventForgeBatch struct {
	BatchNum int64
	// Sender    ethCommon.Address
	EthTxHash ethCommon.Hash
}

// RollupEventUpdateForgeL1L2BatchTimeout is an event of the Rollup Smart Contract
type RollupEventUpdateForgeL1L2BatchTimeout struct {
	NewForgeL1L2BatchTimeout int64
}

// RollupEventUpdateFeeAddToken is an event of the Rollup Smart Contract
type RollupEventUpdateFeeAddToken struct {
	NewFeeAddToken *big.Int
}

// RollupEventWithdrawEvent is an event of the Rollup Smart Contract
type RollupEventWithdrawEvent struct {
	Idx             uint64
	NumExitRoot     uint64
	InstantWithdraw bool
}

// RollupEvents is the list of events in a block of the Rollup Smart Contract
type RollupEvents struct {
	L1UserTx                    []RollupEventL1UserTx
	AddToken                    []RollupEventAddToken
	ForgeBatch                  []RollupEventForgeBatch
	UpdateForgeL1L2BatchTimeout []RollupEventUpdateForgeL1L2BatchTimeout
	UpdateFeeAddToken           []RollupEventUpdateFeeAddToken
	WithdrawEvent               []RollupEventWithdrawEvent
}

// NewRollupEvents creates an empty RollupEvents with the slices initialized.
func NewRollupEvents() RollupEvents {
	return RollupEvents{
		L1UserTx:                    make([]RollupEventL1UserTx, 0),
		AddToken:                    make([]RollupEventAddToken, 0),
		ForgeBatch:                  make([]RollupEventForgeBatch, 0),
		UpdateForgeL1L2BatchTimeout: make([]RollupEventUpdateForgeL1L2BatchTimeout, 0),
		UpdateFeeAddToken:           make([]RollupEventUpdateFeeAddToken, 0),
		WithdrawEvent:               make([]RollupEventWithdrawEvent, 0),
	}
}

// RollupForgeBatchArgs are the arguments to the ForgeBatch function in the Rollup Smart Contract
type RollupForgeBatchArgs struct {
	NewLastIdx            int64
	NewStRoot             *big.Int
	NewExitRoot           *big.Int
	L1CoordinatorTxs      []common.L1Tx
	L1CoordinatorTxsAuths [][]byte // Authorization for accountCreations for each L1CoordinatorTx
	L2TxsData             []common.L2Tx
	FeeIdxCoordinator     []common.Idx
	// Circuit selector
	VerifierIdx uint8
	L1Batch     bool
	ProofA      [2]*big.Int
	ProofB      [2][2]*big.Int
	ProofC      [2]*big.Int
}

// RollupForgeBatchArgsAux are the arguments to the ForgeBatch function in the Rollup Smart Contract
type RollupForgeBatchArgsAux struct {
	NewLastIdx             *big.Int
	NewStRoot              *big.Int
	NewExitRoot            *big.Int
	EncodedL1CoordinatorTx []byte
	L2TxsData              []byte
	FeeIdxCoordinator      []byte
	// Circuit selector
	VerifierIdx uint8
	L1Batch     bool
	ProofA      [2]*big.Int
	ProofB      [2][2]*big.Int
	ProofC      [2]*big.Int
}

// RollupInterface is the inteface to to Rollup Smart Contract
type RollupInterface interface {
	//
	// Smart Contract Methods
	//

	// Public Functions

	RollupForgeBatch(*RollupForgeBatchArgs) (*types.Transaction, error)
	RollupAddToken(tokenAddress ethCommon.Address, feeAddToken *big.Int) (*types.Transaction, error)

	RollupWithdrawMerkleProof(babyPubKey *babyjub.PublicKey, tokenID uint32, numExitRoot, idx int64, amount *big.Int, siblings []*big.Int, instantWithdraw bool) (*types.Transaction, error)
	RollupWithdrawCircuit(proofA, proofC [2]*big.Int, proofB [2][2]*big.Int, tokenID uint32, numExitRoot, idx int64, amount *big.Int, instantWithdraw bool) (*types.Transaction, error)

	RollupL1UserTxERC20ETH(fromBJJ *babyjub.PublicKey, fromIdx int64, loadAmount *big.Int, amount *big.Int, tokenID uint32, toIdx int64) (*types.Transaction, error)
	RollupL1UserTxERC777(fromBJJ *babyjub.PublicKey, fromIdx int64, loadAmount *big.Int, amount *big.Int, tokenID uint32, toIdx int64) (*types.Transaction, error)

	// Governance Public Functions
	RollupUpdateForgeL1L2BatchTimeout(newForgeL1L2BatchTimeout int64) (*types.Transaction, error)
	RollupUpdateFeeAddToken(newFeeAddToken *big.Int) (*types.Transaction, error)

	// Viewers
	RollupRegisterTokensCount() (*big.Int, error)

	//
	// Smart Contract Status
	//

	RollupConstants() (*RollupPublicConstants, error)
	RollupEventsByBlock(blockNum int64) (*RollupEvents, *ethCommon.Hash, error)
	RollupForgeBatchArgs(ethCommon.Hash) (*RollupForgeBatchArgs, *ethCommon.Address, error)
}

//
// Implementation
//

// RollupClient is the implementation of the interface to the Rollup Smart Contract in ethereum.
type RollupClient struct {
	client          *EthereumClient
	address         ethCommon.Address
	tokenHEZAddress ethCommon.Address
	hermez          *Hermez.Hermez
	contractAbi     abi.ABI
}

// NewRollupClient creates a new RollupClient
func NewRollupClient(client *EthereumClient, address ethCommon.Address, tokenHEZAddress ethCommon.Address) (*RollupClient, error) {
	contractAbi, err := abi.JSON(strings.NewReader(string(Hermez.HermezABI)))
	if err != nil {
		return nil, err
	}
	hermez, err := Hermez.NewHermez(address, client.Client())
	if err != nil {
		return nil, err
	}
	return &RollupClient{
		client:          client,
		address:         address,
		tokenHEZAddress: tokenHEZAddress,
		hermez:          hermez,
		contractAbi:     contractAbi,
	}, nil
}

// RollupForgeBatch is the interface to call the smart contract function
func (c *RollupClient) RollupForgeBatch(args *RollupForgeBatchArgs) (tx *types.Transaction, err error) {
	if tx, err = c.client.CallAuth(
		1000000, //nolint:gomnd
		func(ec *ethclient.Client, auth *bind.TransactOpts) (*types.Transaction, error) {
			rollupConst, err := c.RollupConstants()
			if err != nil {
				return nil, err
			}
			nLevels := rollupConst.Verifiers[args.VerifierIdx].NLevels
			lenBytes := nLevels / 8 //nolint:gomnd
			newLastIdx := big.NewInt(int64(args.NewLastIdx))
			var l1CoordinatorBytes []byte
			for i := 0; i < len(args.L1CoordinatorTxs); i++ {
				l1 := args.L1CoordinatorTxs[i]
				bytesl1, err := l1.BytesCoordinatorTx(args.L1CoordinatorTxsAuths[i])
				if err != nil {
					return nil, err
				}
				l1CoordinatorBytes = append(l1CoordinatorBytes, bytesl1[:]...)
			}
			var l2DataBytes []byte
			for i := 0; i < len(args.L2TxsData); i++ {
				l2 := args.L2TxsData[i]
				bytesl2, err := l2.Bytes(int(nLevels))
				if err != nil {
					return nil, err
				}
				l2DataBytes = append(l2DataBytes, bytesl2[:]...)
			}
			var feeIdxCoordinator []byte
			if len(args.FeeIdxCoordinator) > RollupConstMaxFeeIdxCoordinator {
				return nil, fmt.Errorf("len(args.FeeIdxCoordinator) > %v",
					RollupConstMaxFeeIdxCoordinator)
			}
			for i := 0; i < RollupConstMaxFeeIdxCoordinator; i++ {
				feeIdx := common.Idx(0)
				if i < len(args.FeeIdxCoordinator) {
					feeIdx = args.FeeIdxCoordinator[i]
				}
				bytesFeeIdx, err := feeIdx.Bytes()
				if err != nil {
					return nil, err
				}
				feeIdxCoordinator = append(feeIdxCoordinator, bytesFeeIdx[len(bytesFeeIdx)-int(lenBytes):]...)
			}
			return c.hermez.ForgeBatch(auth, newLastIdx, args.NewStRoot, args.NewExitRoot, l1CoordinatorBytes, l2DataBytes, feeIdxCoordinator, args.VerifierIdx, args.L1Batch, args.ProofA, args.ProofB, args.ProofC)
		},
	); err != nil {
		return nil, fmt.Errorf("Failed forge batch: %w", err)
	}
	return tx, nil
}

// RollupAddToken is the interface to call the smart contract function.
// `feeAddToken` is the amount of HEZ tokens that will be paid to add the
// token.  `feeAddToken` must match the public value of the smart contract.
func (c *RollupClient) RollupAddToken(tokenAddress ethCommon.Address, feeAddToken *big.Int) (tx *types.Transaction, err error) {
	if tx, err = c.client.CallAuth(
		0,
		func(ec *ethclient.Client, auth *bind.TransactOpts) (*types.Transaction, error) {
			tokens, err := ERC777.NewERC777(c.tokenHEZAddress, ec)
			if err != nil {
				return nil, err
			}
			addTokenFnSignature := []byte("addToken(address)")
			hash := sha3.NewLegacyKeccak256()
			_, err = hash.Write(addTokenFnSignature)
			if err != nil {
				return nil, err
			}
			methodID := hash.Sum(nil)[:4]
			var data []byte
			data = append(data, methodID...)
			paddedAddress := ethCommon.LeftPadBytes(tokenAddress.Bytes(), 32)
			data = append(data, paddedAddress[:]...)
			return tokens.Send(auth, c.address, feeAddToken, data)
		},
	); err != nil {
		return nil, fmt.Errorf("Failed add Token %w", err)
	}
	return tx, nil
}

// RollupWithdrawMerkleProof is the interface to call the smart contract function
func (c *RollupClient) RollupWithdrawMerkleProof(fromBJJ *babyjub.PublicKey, tokenID uint32, numExitRoot, idx int64, amount *big.Int, siblings []*big.Int, instantWithdraw bool) (tx *types.Transaction, err error) {
	if tx, err = c.client.CallAuth(
		0,
		func(ec *ethclient.Client, auth *bind.TransactOpts) (*types.Transaction, error) {
			hermez, err := Hermez.NewHermez(c.address, ec)
			if err != nil {
				return nil, err
			}
			pkCompL := fromBJJ.Compress()
			pkCompB := common.SwapEndianness(pkCompL[:])
			babyPubKey := new(big.Int).SetBytes(pkCompB)
			numExitRootB := big.NewInt(numExitRoot)
			idxBig := big.NewInt(idx)
			return hermez.WithdrawMerkleProof(auth, tokenID, amount, babyPubKey, numExitRootB, siblings, idxBig, instantWithdraw)
		},
	); err != nil {
		return nil, fmt.Errorf("Failed update WithdrawMerkleProof: %w", err)
	}
	return tx, nil
}

// RollupWithdrawCircuit is the interface to call the smart contract function
func (c *RollupClient) RollupWithdrawCircuit(proofA, proofC [2]*big.Int, proofB [2][2]*big.Int, tokenID uint32, numExitRoot, idx int64, amount *big.Int, instantWithdraw bool) (*types.Transaction, error) {
	log.Error("TODO")
	return nil, errTODO
}

// RollupL1UserTxERC20ETH is the interface to call the smart contract function
func (c *RollupClient) RollupL1UserTxERC20ETH(fromBJJ *babyjub.PublicKey, fromIdx int64, loadAmount *big.Int, amount *big.Int, tokenID uint32, toIdx int64) (tx *types.Transaction, err error) {
	if tx, err = c.client.CallAuth(
		0,
		func(ec *ethclient.Client, auth *bind.TransactOpts) (*types.Transaction, error) {
			hermez, err := Hermez.NewHermez(c.address, ec)
			if err != nil {
				return nil, err
			}
			pkCompL := fromBJJ.Compress()
			pkCompB := common.SwapEndianness(pkCompL[:])
			babyPubKey := new(big.Int).SetBytes(pkCompB)
			fromIdxBig := big.NewInt(fromIdx)
			toIdxBig := big.NewInt(toIdx)
			tokenIDBig := uint32(tokenID)
			loadAmountF, err := common.NewFloat16(loadAmount)
			if err != nil {
				return nil, err
			}
			amountF, err := common.NewFloat16(amount)
			if err != nil {
				return nil, err
			}
			if tokenID == 0 {
				auth.Value = loadAmount
			}
			return hermez.AddL1Transaction(auth, babyPubKey, fromIdxBig, uint16(loadAmountF), uint16(amountF), tokenIDBig, toIdxBig)
		},
	); err != nil {
		return nil, fmt.Errorf("Failed add L1 Tx ERC20/ETH: %w", err)
	}
	return tx, nil
}

// RollupL1UserTxERC777 is the interface to call the smart contract function
func (c *RollupClient) RollupL1UserTxERC777(fromBJJ *babyjub.PublicKey, fromIdx int64, loadAmount *big.Int, amount *big.Int, tokenID uint32, toIdx int64) (tx *types.Transaction, err error) {
	if tx, err = c.client.CallAuth(
		0,
		func(ec *ethclient.Client, auth *bind.TransactOpts) (*types.Transaction, error) {
			tokens, err := ERC777.NewERC777(c.tokenHEZAddress, ec)
			if err != nil {
				return nil, err
			}
			addL1TxFnSignature := []byte("addL1Transaction(uint256,uint48,uint16,uint16,uint32,uint48)")
			hash := sha3.NewLegacyKeccak256()
			_, err = hash.Write(addL1TxFnSignature)
			if err != nil {
				return nil, err
			}
			methodID := hash.Sum(nil)[:4]
			pkCompL := fromBJJ.Compress()
			pkCompB := common.SwapEndianness(pkCompL[:])
			paddedAddress := ethCommon.LeftPadBytes(pkCompB, 32)
			fromIdxB, err := common.Idx(fromIdx).Bytes()
			if err != nil {
				return nil, err
			}
			paddedFromIdx := ethCommon.LeftPadBytes(fromIdxB[:], 32)
			loadAmountF, err := common.NewFloat16(loadAmount)
			if err != nil {
				return nil, err
			}
			paddedLoadAmount := ethCommon.LeftPadBytes(loadAmountF.Bytes(), 32)
			amountF, err := common.NewFloat16(amount)
			if err != nil {
				return nil, err
			}
			paddedAmount := ethCommon.LeftPadBytes(amountF.Bytes(), 32)
			tokenIDB := common.TokenID(tokenID).Bytes()
			paddedTokenID := ethCommon.LeftPadBytes(tokenIDB, 32)
			toIdxB, err := common.Idx(toIdx).Bytes()
			if err != nil {
				return nil, err
			}
			paddedToIdx := ethCommon.LeftPadBytes(toIdxB[:], 32)
			var data []byte
			data = append(data, methodID...)
			data = append(data, paddedAddress[:]...)
			data = append(data, paddedFromIdx[:]...)
			data = append(data, paddedLoadAmount[:]...)
			data = append(data, paddedAmount[:]...)
			data = append(data, paddedTokenID[:]...)
			data = append(data, paddedToIdx[:]...)
			return tokens.Send(auth, c.address, loadAmount, data)
		},
	); err != nil {
		return nil, fmt.Errorf("Failed add L1 Tx ERC777: %w", err)
	}
	return tx, nil
}

// RollupRegisterTokensCount is the interface to call the smart contract function
func (c *RollupClient) RollupRegisterTokensCount() (*big.Int, error) {
	var registerTokensCount *big.Int
	if err := c.client.Call(func(ec *ethclient.Client) error {
		hermez, err := Hermez.NewHermez(c.address, ec)
		if err != nil {
			return err
		}
		registerTokensCount, err = hermez.RegisterTokensCount(nil)
		return err
	}); err != nil {
		return nil, err
	}
	return registerTokensCount, nil
}

// RollupUpdateForgeL1L2BatchTimeout is the interface to call the smart contract function
func (c *RollupClient) RollupUpdateForgeL1L2BatchTimeout(newForgeL1L2BatchTimeout int64) (tx *types.Transaction, err error) {
	if tx, err = c.client.CallAuth(
		0,
		func(ec *ethclient.Client, auth *bind.TransactOpts) (*types.Transaction, error) {
			hermez, err := Hermez.NewHermez(c.address, ec)
			if err != nil {
				return nil, err
			}
			return hermez.UpdateForgeL1L2BatchTimeout(auth, uint8(newForgeL1L2BatchTimeout))
		},
	); err != nil {
		return nil, fmt.Errorf("Failed update ForgeL1L2BatchTimeout: %w", err)
	}
	return tx, nil
}

// RollupUpdateFeeAddToken is the interface to call the smart contract function
func (c *RollupClient) RollupUpdateFeeAddToken(newFeeAddToken *big.Int) (tx *types.Transaction, err error) {
	if tx, err = c.client.CallAuth(
		0,
		func(ec *ethclient.Client, auth *bind.TransactOpts) (*types.Transaction, error) {
			hermez, err := Hermez.NewHermez(c.address, ec)
			if err != nil {
				return nil, err
			}
			return hermez.UpdateFeeAddToken(auth, newFeeAddToken)
		},
	); err != nil {
		return nil, fmt.Errorf("Failed update FeeAddToken: %w", err)
	}
	return tx, nil
}

// RollupConstants returns the Constants of the Rollup Smart Contract
func (c *RollupClient) RollupConstants() (rollupConstants *RollupPublicConstants, err error) {
	rollupConstants = new(RollupPublicConstants)
	if err := c.client.Call(func(ec *ethclient.Client) error {
		absoluteMaxL1L2BatchTimeout, err := c.hermez.ABSOLUTEMAXL1L2BATCHTIMEOUT(nil)
		if err != nil {
			return err
		}
		rollupConstants.AbsoluteMaxL1L2BatchTimeout = int64(absoluteMaxL1L2BatchTimeout)
		rollupConstants.TokenHEZ, err = c.hermez.TokenHEZ(nil)
		if err != nil {
			return err
		}
		for i := int64(0); i < int64(LenVerifiers); i++ {
			var newRollupVerifier RollupVerifierStruct
			rollupVerifier, err := c.hermez.RollupVerifiers(nil, big.NewInt(i))
			if err != nil {
				return err
			}
			newRollupVerifier.MaxTx = rollupVerifier.MaxTx.Int64()
			newRollupVerifier.NLevels = rollupVerifier.NLevels.Int64()
			rollupConstants.Verifiers = append(rollupConstants.Verifiers, newRollupVerifier)
		}
		rollupConstants.HermezAuctionContract, err = c.hermez.HermezAuctionContract(nil)
		if err != nil {
			return err
		}
		rollupConstants.HermezGovernanceDAOAddress, err = c.hermez.HermezGovernanceDAOAddress(nil)
		if err != nil {
			return err
		}
		rollupConstants.SafetyAddress, err = c.hermez.SafetyAddress(nil)
		if err != nil {
			return err
		}
		rollupConstants.WithdrawDelayerContract, err = c.hermez.WithdrawDelayerContract(nil)
		return err
	}); err != nil {
		return nil, err
	}
	return rollupConstants, nil
}

var (
	logHermezL1UserTxEvent               = crypto.Keccak256Hash([]byte("L1UserTxEvent(uint64,uint8,bytes)"))
	logHermezAddToken                    = crypto.Keccak256Hash([]byte("AddToken(address,uint32)"))
	logHermezForgeBatch                  = crypto.Keccak256Hash([]byte("ForgeBatch(uint64)"))
	logHermezUpdateForgeL1L2BatchTimeout = crypto.Keccak256Hash([]byte("UpdateForgeL1L2BatchTimeout(uint8)"))
	logHermezUpdateFeeAddToken           = crypto.Keccak256Hash([]byte("UpdateFeeAddToken(uint256)"))
	logHermezWithdrawEvent               = crypto.Keccak256Hash([]byte("WithdrawEvent(uint48,uint48,bool)"))
)

// RollupEventsByBlock returns the events in a block that happened in the Rollup Smart Contract
func (c *RollupClient) RollupEventsByBlock(blockNum int64) (*RollupEvents, *ethCommon.Hash, error) {
	var rollupEvents RollupEvents
	var blockHash ethCommon.Hash

	query := ethereum.FilterQuery{
		FromBlock: big.NewInt(blockNum),
		ToBlock:   big.NewInt(blockNum),
		Addresses: []ethCommon.Address{
			c.address,
		},
		BlockHash: nil,
		Topics:    [][]ethCommon.Hash{},
	}
	logs, err := c.client.client.FilterLogs(context.Background(), query)
	if err != nil {
		return nil, nil, err
	}
	if len(logs) > 0 {
		blockHash = logs[0].BlockHash
	}
	for _, vLog := range logs {
		if vLog.BlockHash != blockHash {
			return nil, nil, ErrBlockHashMismatchEvent
		}
		switch vLog.Topics[0] {
		case logHermezL1UserTxEvent:
			var L1UserTxAux RollupEventL1UserTxAux
			var L1UserTx RollupEventL1UserTx
			err := c.contractAbi.Unpack(&L1UserTxAux, "L1UserTxEvent", vLog.Data)
			if err != nil {
				return nil, nil, err
			}
			L1Tx, err := common.L1UserTxFromBytes(L1UserTxAux.L1UserTx)
			if err != nil {
				return nil, nil, err
			}
			toForgeL1TxsNum := new(big.Int).SetBytes(vLog.Topics[1][:]).Int64()
			L1Tx.ToForgeL1TxsNum = &toForgeL1TxsNum
			L1Tx.Position = int(new(big.Int).SetBytes(vLog.Topics[2][:]).Int64())
			L1Tx.UserOrigin = true
			L1UserTx.L1UserTx = *L1Tx
			rollupEvents.L1UserTx = append(rollupEvents.L1UserTx, L1UserTx)
		case logHermezAddToken:
			var addToken RollupEventAddToken
			err := c.contractAbi.Unpack(&addToken, "AddToken", vLog.Data)
			if err != nil {
				return nil, nil, err
			}
			addToken.TokenAddress = ethCommon.BytesToAddress(vLog.Topics[1].Bytes())
			rollupEvents.AddToken = append(rollupEvents.AddToken, addToken)
		case logHermezForgeBatch:
			var forgeBatch RollupEventForgeBatch
			forgeBatch.BatchNum = new(big.Int).SetBytes(vLog.Topics[1][:]).Int64()
			forgeBatch.EthTxHash = vLog.TxHash
			// forgeBatch.Sender = vLog.Address
			rollupEvents.ForgeBatch = append(rollupEvents.ForgeBatch, forgeBatch)
		case logHermezUpdateForgeL1L2BatchTimeout:
			var updateForgeL1L2BatchTimeout struct {
				NewForgeL1L2BatchTimeout uint8
			}
			err := c.contractAbi.Unpack(&updateForgeL1L2BatchTimeout, "UpdateForgeL1L2BatchTimeout", vLog.Data)
			if err != nil {
				return nil, nil, err
			}
			rollupEvents.UpdateForgeL1L2BatchTimeout = append(rollupEvents.UpdateForgeL1L2BatchTimeout,
				RollupEventUpdateForgeL1L2BatchTimeout{
					NewForgeL1L2BatchTimeout: int64(updateForgeL1L2BatchTimeout.NewForgeL1L2BatchTimeout),
				})
		case logHermezUpdateFeeAddToken:
			var updateFeeAddToken RollupEventUpdateFeeAddToken
			err := c.contractAbi.Unpack(&updateFeeAddToken, "UpdateFeeAddToken", vLog.Data)
			if err != nil {
				return nil, nil, err
			}
			rollupEvents.UpdateFeeAddToken = append(rollupEvents.UpdateFeeAddToken, updateFeeAddToken)
		case logHermezWithdrawEvent:
			var withdraw RollupEventWithdrawEvent
			withdraw.Idx = new(big.Int).SetBytes(vLog.Topics[1][:]).Uint64()
			withdraw.NumExitRoot = new(big.Int).SetBytes(vLog.Topics[2][:]).Uint64()
			instantWithdraw := new(big.Int).SetBytes(vLog.Topics[3][:]).Uint64()
			if instantWithdraw == 1 {
				withdraw.InstantWithdraw = true
			}
			rollupEvents.WithdrawEvent = append(rollupEvents.WithdrawEvent, withdraw)
		}
	}
	return &rollupEvents, &blockHash, nil
}

// RollupForgeBatchArgs returns the arguments used in a ForgeBatch call in the
// Rollup Smart Contract in the given transaction, and the sender address.
func (c *RollupClient) RollupForgeBatchArgs(ethTxHash ethCommon.Hash) (*RollupForgeBatchArgs, *ethCommon.Address, error) {
	tx, _, err := c.client.client.TransactionByHash(context.Background(), ethTxHash)
	if err != nil {
		return nil, nil, err
	}
	txData := tx.Data()
	method, err := c.contractAbi.MethodById(txData[:4])
	if err != nil {
		return nil, nil, err
	}
	receipt, err := c.client.client.TransactionReceipt(context.Background(), ethTxHash)
	if err != nil {
		return nil, nil, err
	}
	sender, err := c.client.client.TransactionSender(context.Background(), tx, receipt.Logs[0].BlockHash, receipt.Logs[0].Index)
	if err != nil {
		return nil, nil, err
	}
	var aux RollupForgeBatchArgsAux
	if err := method.Inputs.Unpack(&aux, txData[4:]); err != nil {
		return nil, nil, err
	}
	rollupForgeBatchArgs := RollupForgeBatchArgs{
		L1Batch:               aux.L1Batch,
		NewExitRoot:           aux.NewExitRoot,
		NewLastIdx:            aux.NewLastIdx.Int64(),
		NewStRoot:             aux.NewStRoot,
		ProofA:                aux.ProofA,
		ProofB:                aux.ProofB,
		ProofC:                aux.ProofC,
		VerifierIdx:           aux.VerifierIdx,
		L1CoordinatorTxs:      []common.L1Tx{},
		L1CoordinatorTxsAuths: [][]byte{},
		L2TxsData:             []common.L2Tx{},
		FeeIdxCoordinator:     []common.Idx{},
	}
	numTxsL1 := len(aux.EncodedL1CoordinatorTx) / common.L1CoordinatorTxBytesLen
	for i := 0; i < numTxsL1; i++ {
		bytesL1Coordinator := aux.EncodedL1CoordinatorTx[i*common.L1CoordinatorTxBytesLen : (i+1)*common.L1CoordinatorTxBytesLen]
		var signature []byte
		v := bytesL1Coordinator[0]
		s := bytesL1Coordinator[1:33]
		r := bytesL1Coordinator[33:65]
		signature = append(signature, r[:]...)
		signature = append(signature, s[:]...)
		signature = append(signature, v)
		l1Tx, err := common.L1CoordinatorTxFromBytes(bytesL1Coordinator)
		if err != nil {
			return nil, nil, err
		}
		rollupForgeBatchArgs.L1CoordinatorTxs = append(rollupForgeBatchArgs.L1CoordinatorTxs, *l1Tx)
		rollupForgeBatchArgs.L1CoordinatorTxsAuths = append(rollupForgeBatchArgs.L1CoordinatorTxsAuths, signature)
	}
	rollupConsts, err := c.RollupConstants()
	if err != nil {
		return nil, nil, err
	}
	nLevels := rollupConsts.Verifiers[rollupForgeBatchArgs.VerifierIdx].NLevels
	lenL2TxsBytes := int((nLevels/8)*2 + 2 + 1)
	numTxsL2 := len(aux.L2TxsData) / lenL2TxsBytes
	for i := 0; i < numTxsL2; i++ {
		l2Tx, err := common.L2TxFromBytes(aux.L2TxsData[i*lenL2TxsBytes:(i+1)*lenL2TxsBytes], int(nLevels))
		if err != nil {
			return nil, nil, err
		}
		rollupForgeBatchArgs.L2TxsData = append(rollupForgeBatchArgs.L2TxsData, *l2Tx)
	}
	lenFeeIdxCoordinatorBytes := int(nLevels / 8) //nolint:gomnd
	numFeeIdxCoordinator := len(aux.FeeIdxCoordinator) / lenFeeIdxCoordinatorBytes
	for i := 0; i < numFeeIdxCoordinator; i++ {
		var paddedFeeIdx [6]byte
		// TODO: This check is not necessary: the first case will always work.  Test it before removing the if.
		if lenFeeIdxCoordinatorBytes < common.IdxBytesLen {
			copy(paddedFeeIdx[6-lenFeeIdxCoordinatorBytes:], aux.FeeIdxCoordinator[i*lenFeeIdxCoordinatorBytes:(i+1)*lenFeeIdxCoordinatorBytes])
		} else {
			copy(paddedFeeIdx[:], aux.FeeIdxCoordinator[i*lenFeeIdxCoordinatorBytes:(i+1)*lenFeeIdxCoordinatorBytes])
		}
		feeIdxCoordinator, err := common.IdxFromBytes(paddedFeeIdx[:])
		if err != nil {
			return nil, nil, err
		}
		if feeIdxCoordinator != common.Idx(0) {
			rollupForgeBatchArgs.FeeIdxCoordinator = append(rollupForgeBatchArgs.FeeIdxCoordinator, feeIdxCoordinator)
		}
	}
	return &rollupForgeBatchArgs, &sender, nil
}