web3_account_api.go

package service

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"math/big"

	//"strings"
	"time"

	//"github.com/davecgh/go-spew/spew"
	"github.com/ethereum/go-ethereum/accounts"
	"github.com/ethereum/go-ethereum/accounts/keystore"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/common/math"

	//"github.com/ethereum/go-ethereum/consensus/ethash"

	//"github.com/ethereum/go-ethereum/core"
	//"github.com/ethereum/go-ethereum/core/rawdb"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/core/vm"
	"github.com/ethereum/go-ethereum/crypto"

	"github.com/ethereum/go-ethereum/log"
	"github.com/ethereum/go-ethereum/p2p"
	"github.com/ethereum/go-ethereum/params"
	"github.com/ethereum/go-ethereum/rlp"
	"github.com/ethereum/go-ethereum/rpc"
	//"github.com/syndtr/goleveldb/leveldb"
	//"github.com/syndtr/goleveldb/leveldb/util"
)

var (
	defaultGasPrice = new(big.Int).Mul(big.NewInt(1), big.NewInt(params.GWei))
)

// PublicEthereumAPI provides an API to access Ethereum related information.
// It offers only methods that operate on public data that is freely available to anyone.
type PublicEthereumAPI struct {
	backend *Service
}

// NewPublicEthereumAPI creates a new Ethereum protocol API.
func NewPublicEthereumAPI(b *Service) *PublicEthereumAPI {
	return &PublicEthereumAPI{b}
}

// GasPrice returns a suggestion for a gas price.
func (s *PublicEthereumAPI) GasPrice(ctx context.Context) (*hexutil.Big, error) {
	return nil, ErrNotImplemented
}

// ProtocolVersion returns the current Ethereum protocol version this node supports
func (s *PublicEthereumAPI) ProtocolVersion() hexutil.Uint {
	// TODO: return valid value
	return 3
}

// Syncing returns false in case the node is currently not syncing with the network. It can be up to date or has not
// yet received the latest block headers from its pears. In case it is synchronizing:
// - startingBlock: block number this node started to synchronise from
// - currentBlock:  block number this node is currently importing
// - highestBlock:  block number of the highest block header this node has received from peers
// - pulledStates:  number of state entries processed until now
// - knownStates:   number of known state entries that still need to be pulled
func (s *PublicEthereumAPI) Syncing() (interface{}, error) {
	/*
		progress := s.backend.Downloader().Progress()

		// Return not syncing if the synchronisation already completed
		if progress.CurrentBlock >= progress.HighestBlock {
			return false, nil
		}
		// Otherwise gather the block sync stats
		return map[string]interface{}{
			"startingBlock": hexutil.Uint64(progress.StartingBlock),
			"currentBlock":  hexutil.Uint64(progress.CurrentBlock),
			"highestBlock":  hexutil.Uint64(progress.HighestBlock),
			"pulledStates":  hexutil.Uint64(progress.PulledStates),
			"knownStates":   hexutil.Uint64(progress.KnownStates),
		}, nil
	*/
	return nil, ErrNotImplemented
}

// PublicTxPoolAPI offers and API for the transaction pool. It only operates on data that is non confidential.
type PublicTxPoolAPI struct {
	backend *Service
}

// NewPublicTxPoolAPI creates a new tx pool service that gives information about the transaction pool.
func NewPublicTxPoolAPI(b *Service) *PublicTxPoolAPI {
	return &PublicTxPoolAPI{b}
}

// Content returns the transactions contained within the transaction pool.
func (s *PublicTxPoolAPI) Content() map[string]map[string]map[string]*RPCTransaction {
	/*
		content := map[string]map[string]map[string]*RPCTransaction{
			"pending": make(map[string]map[string]*RPCTransaction),
			"queued":  make(map[string]map[string]*RPCTransaction),
		}
		pending, queue := s.backend.TxPoolContent()

		// Flatten the pending transactions
		for account, txs := range pending {
			dump := make(map[string]*RPCTransaction)
			for _, tx := range txs {
				dump[fmt.Sprintf("%d", tx.Nonce())] = newRPCPendingTransaction(tx)
			}
			content["pending"][account.Hex()] = dump
		}
		// Flatten the queued transactions
		for account, txs := range queue {
			dump := make(map[string]*RPCTransaction)
			for _, tx := range txs {
				dump[fmt.Sprintf("%d", tx.Nonce())] = newRPCPendingTransaction(tx)
			}
			content["queued"][account.Hex()] = dump
		}
		return content
	*/
	return nil
}

// Status returns the number of pending and queued transaction in the pool.
func (s *PublicTxPoolAPI) Status() map[string]hexutil.Uint {
	/*
		pending, queue := s.backend.Stats()
		return map[string]hexutil.Uint{
			"pending": hexutil.Uint(pending),
			"queued":  hexutil.Uint(queue),
		}
	*/
	return nil
}

// Inspect retrieves the content of the transaction pool and flattens it into an
// easily inspectable list.
func (s *PublicTxPoolAPI) Inspect() map[string]map[string]map[string]string {
	/*
		content := map[string]map[string]map[string]string{
			"pending": make(map[string]map[string]string),
			"queued":  make(map[string]map[string]string),
		}
		pending, queue := s.backend.TxPoolContent()

		// Define a formatter to flatten a transaction into a string
		var format = func(tx *types.Transaction) string {
			if to := tx.To(); to != nil {
				return fmt.Sprintf("%s: %v wei + %v gas × %v wei", tx.To().Hex(), tx.Value(), tx.Gas(), tx.GasPrice())
			}
			return fmt.Sprintf("contract creation: %v wei + %v gas × %v wei", tx.Value(), tx.Gas(), tx.GasPrice())
		}
		// Flatten the pending transactions
		for account, txs := range pending {
			dump := make(map[string]string)
			for _, tx := range txs {
				dump[fmt.Sprintf("%d", tx.Nonce())] = format(tx)
			}
			content["pending"][account.Hex()] = dump
		}
		// Flatten the queued transactions
		for account, txs := range queue {
			dump := make(map[string]string)
			for _, tx := range txs {
				dump[fmt.Sprintf("%d", tx.Nonce())] = format(tx)
			}
			content["queued"][account.Hex()] = dump
		}
		return content
	*/
	return nil
}

// PublicAccountAPI provides an API to access accounts managed by this node.
// It offers only methods that can retrieve accounts.
type PublicAccountAPI struct {
	am *accounts.Manager
}

// NewPublicAccountAPI creates a new PublicAccountAPI.
func NewPublicAccountAPI(am *accounts.Manager) *PublicAccountAPI {
	return &PublicAccountAPI{am: am}
}

// Accounts returns the collection of accounts this node manages
func (s *PublicAccountAPI) Accounts() []common.Address {
	addresses := make([]common.Address, 0) // return [] instead of nil if empty
	for _, wallet := range s.am.Wallets() {
		for _, account := range wallet.Accounts() {
			addresses = append(addresses, account.Address)
		}
	}
	return addresses
}

// PrivateAccountAPI provides an API to access accounts managed by this node.
// It offers methods to create, (un)lock en list accounts. Some methods accept
// passwords and are therefore considered private by default.
type PrivateAccountAPI struct {
	am        *accounts.Manager
	nonceLock *AddrLocker
	backend   *Service
}

// NewPrivateAccountAPI create a new PrivateAccountAPI.
func NewPrivateAccountAPI(b *Service, nonceLock *AddrLocker) *PrivateAccountAPI {
	return &PrivateAccountAPI{
		am:        b.AccountManager(),
		nonceLock: nonceLock,
		backend:   b,
	}
}

// ListAccounts will return a list of addresses for accounts this node manages.
func (s *PrivateAccountAPI) ListAccounts() []common.Address {
	addresses := make([]common.Address, 0) // return [] instead of nil if empty
	for _, wallet := range s.am.Wallets() {
		for _, account := range wallet.Accounts() {
			addresses = append(addresses, account.Address)
		}
	}
	return addresses
}

// rawWallet is a JSON representation of an accounts.Wallet interface, with its
// data contents extracted into plain fields.
type rawWallet struct {
	URL      string             `json:"url"`
	Status   string             `json:"status"`
	Failure  string             `json:"failure,omitempty"`
	Accounts []accounts.Account `json:"accounts,omitempty"`
}

// ListWallets will return a list of wallets this node manages.
func (s *PrivateAccountAPI) ListWallets() []rawWallet {
	wallets := make([]rawWallet, 0) // return [] instead of nil if empty
	for _, wallet := range s.am.Wallets() {
		status, failure := wallet.Status()

		raw := rawWallet{
			URL:      wallet.URL().String(),
			Status:   status,
			Accounts: wallet.Accounts(),
		}
		if failure != nil {
			raw.Failure = failure.Error()
		}
		wallets = append(wallets, raw)
	}
	return wallets
}

// OpenWallet initiates a hardware wallet opening procedure, establishing a USB
// connection and attempting to authenticate via the provided passphrase. Note,
// the method may return an extra challenge requiring a second open (e.g. the
// Trezor PIN matrix challenge).
func (s *PrivateAccountAPI) OpenWallet(url string, passphrase *string) error {
	wallet, err := s.am.Wallet(url)
	if err != nil {
		return err
	}
	pass := ""
	if passphrase != nil {
		pass = *passphrase
	}
	return wallet.Open(pass)
}

// DeriveAccount requests a HD wallet to derive a new account, optionally pinning
// it for later reuse.
func (s *PrivateAccountAPI) DeriveAccount(url string, path string, pin *bool) (accounts.Account, error) {
	wallet, err := s.am.Wallet(url)
	if err != nil {
		return accounts.Account{}, err
	}
	derivPath, err := accounts.ParseDerivationPath(path)
	if err != nil {
		return accounts.Account{}, err
	}
	if pin == nil {
		pin = new(bool)
	}
	return wallet.Derive(derivPath, *pin)
}

// NewAccount will create a new account and returns the address for the new account.
func (s *PrivateAccountAPI) NewAccount(password string) (common.Address, error) {
	acc, err := fetchKeystore(s.am).NewAccount(password)
	if err == nil {
		return acc.Address, nil
	}
	return common.Address{}, err
}

// fetchKeystore retrives the encrypted keystore from the account manager.
func fetchKeystore(am *accounts.Manager) *keystore.KeyStore {
	return am.Backends(keystore.KeyStoreType)[0].(*keystore.KeyStore)
}

// ImportRawKey stores the given hex encoded ECDSA key into the key directory,
// encrypting it with the passphrase.
func (s *PrivateAccountAPI) ImportRawKey(privkey string, password string) (common.Address, error) {
	key, err := crypto.HexToECDSA(privkey)
	if err != nil {
		return common.Address{}, err
	}
	acc, err := fetchKeystore(s.am).ImportECDSA(key, password)
	return acc.Address, err
}

// UnlockAccount will unlock the account associated with the given address with
// the given password for duration seconds. If duration is nil it will use a
// default of 300 seconds. It returns an indication if the account was unlocked.
func (s *PrivateAccountAPI) UnlockAccount(addr common.Address, password string, duration *uint64) (bool, error) {
	const max = uint64(time.Duration(math.MaxInt64) / time.Second)
	var d time.Duration
	if duration == nil {
		d = 300 * time.Second
	} else if *duration > max {
		return false, errors.New("unlock duration too large")
	} else {
		d = time.Duration(*duration) * time.Second
	}
	err := fetchKeystore(s.am).TimedUnlock(accounts.Account{Address: addr}, password, d)
	return err == nil, err
}

// LockAccount will lock the account associated with the given address when it's unlocked.
func (s *PrivateAccountAPI) LockAccount(addr common.Address) bool {
	return fetchKeystore(s.am).Lock(addr) == nil
}

// signTransactions sets defaults and signs the given transaction
// NOTE: the caller needs to ensure that the nonceLock is held, if applicable,
// and release it after the transaction has been submitted to the tx pool
func (s *PrivateAccountAPI) signTransaction(ctx context.Context, args SendTxArgs, passwd string) (*types.Transaction, error) {
	// Look up the wallet containing the requested signer
	account := accounts.Account{Address: args.From}
	wallet, err := s.am.Find(account)
	if err != nil {
		return nil, err
	}
	// Set some sanity defaults and terminate on failure
	if err := args.setDefaults(ctx, s.backend); err != nil {
		return nil, err
	}
	// Assemble the transaction and sign with the wallet
	tx := args.toTransaction()

	chainID := s.backend.ChainConfig().ChainID

	return wallet.SignTxWithPassphrase(account, passwd, tx, chainID)
}

// SendTransaction will create a transaction from the given arguments and
// tries to sign it with the key associated with args.To. If the given passwd isn't
// able to decrypt the key it fails.
func (s *PrivateAccountAPI) SendTransaction(ctx context.Context, args SendTxArgs, passwd string) (common.Hash, error) {
	if args.Nonce == nil {
		// Hold the address's mutex around signing to prevent concurrent assignment of
		// the same nonce to multiple accounts.
		s.nonceLock.LockAddr(args.From)
		defer s.nonceLock.UnlockAddr(args.From)
	}
	signed, err := s.signTransaction(ctx, args, passwd)
	if err != nil {
		return common.Hash{}, err
	}
	return submitTransaction(ctx, s.backend, signed)
}

// SignTransaction will create a transaction from the given arguments and
// tries to sign it with the key associated with args.To. If the given passwd isn't
// able to decrypt the key it fails. The transaction is returned in RLP-form, not broadcast
// to other nodes
func (s *PrivateAccountAPI) SignTransaction(ctx context.Context, args SendTxArgs, passwd string) (*SignTransactionResult, error) {

	// No need to obtain the noncelock mutex, since we won't be sending this
	// tx into the transaction pool, but right back to the user
	if args.Gas == nil {
		return nil, fmt.Errorf("gas not specified")
	}
	if args.GasPrice == nil {
		return nil, fmt.Errorf("gasPrice not specified")
	}
	if args.Nonce == nil {
		return nil, fmt.Errorf("nonce not specified")
	}
	signed, err := s.signTransaction(ctx, args, passwd)
	if err != nil {
		return nil, err
	}
	data, err := rlp.EncodeToBytes(signed)
	if err != nil {
		return nil, err
	}
	return &SignTransactionResult{data, signed}, nil
}

// signHash is a helper function that calculates a hash for the given message that can be
// safely used to calculate a signature from.
//
// The hash is calulcated as
//   keccak256("\x19Ethereum Signed Message:\n"${message length}${message}).
//
// This gives context to the signed message and prevents signing of transactions.
func signHash(data []byte) []byte {
	msg := fmt.Sprintf("\x19Ethereum Signed Message:\n%d%s", len(data), data)
	return crypto.Keccak256([]byte(msg))
}

// Sign calculates an Ethereum ECDSA signature for:
// keccack256("\x19Ethereum Signed Message:\n" + len(message) + message))
//
// Note, the produced signature conforms to the secp256k1 curve R, S and V values,
// where the V value will be 27 or 28 for legacy reasons.
//
// The key used to calculate the signature is decrypted with the given password.
//
// https://github.com/ethereum/go-ethereum/wiki/Management-APIs#personal_sign
func (s *PrivateAccountAPI) Sign(ctx context.Context, data hexutil.Bytes, addr common.Address, passwd string) (hexutil.Bytes, error) {
	// Look up the wallet containing the requested signer
	account := accounts.Account{Address: addr}

	wallet, err := s.backend.AccountManager().Find(account)
	if err != nil {
		return nil, err
	}
	// Assemble sign the data with the wallet
	signature, err := wallet.SignHashWithPassphrase(account, passwd, signHash(data))
	if err != nil {
		return nil, err
	}
	signature[64] += 27 // Transform V from 0/1 to 27/28 according to the yellow paper
	return signature, nil
}

// EcRecover returns the address for the account that was used to create the signature.
// Note, this function is compatible with eth_sign and personal_sign. As such it recovers
// the address of:
// hash = keccak256("\x19Ethereum Signed Message:\n"${message length}${message})
// addr = ecrecover(hash, signature)
//
// Note, the signature must conform to the secp256k1 curve R, S and V values, where
// the V value must be 27 or 28 for legacy reasons.
//
// https://github.com/ethereum/go-ethereum/wiki/Management-APIs#personal_ecRecover
func (s *PrivateAccountAPI) EcRecover(ctx context.Context, data, sig hexutil.Bytes) (common.Address, error) {
	if len(sig) != 65 {
		return common.Address{}, fmt.Errorf("signature must be 65 bytes long")
	}
	if sig[64] != 27 && sig[64] != 28 {
		return common.Address{}, fmt.Errorf("invalid Ethereum signature (V is not 27 or 28)")
	}
	sig[64] -= 27 // Transform yellow paper V from 27/28 to 0/1

	rpk, err := crypto.SigToPub(signHash(data), sig)
	if err != nil {
		return common.Address{}, err
	}
	return crypto.PubkeyToAddress(*rpk), nil
}

// SignAndSendTransaction was renamed to SendTransaction. This method is deprecated
// and will be removed in the future. It primary goal is to give clients time to update.
func (s *PrivateAccountAPI) SignAndSendTransaction(ctx context.Context, args SendTxArgs, passwd string) (common.Hash, error) {
	return s.SendTransaction(ctx, args, passwd)
}

// PublicBlockChainAPI provides an API to access the Ethereum blockchain.
// It offers only methods that operate on public data that is freely available to anyone.
type PublicBlockChainAPI struct {
	backend *Service
}

// NewPublicBlockChainAPI creates a new Ethereum blockchain API.
func NewPublicBlockChainAPI(b *Service) *PublicBlockChainAPI {
	return &PublicBlockChainAPI{b}
}

// BlockNumber returns the block number of the chain head.
func (s *PublicBlockChainAPI) BlockNumber() hexutil.Uint64 {
	return hexutil.Uint64(s.backend.state.GetBlockIndex())
}

// GetBalance returns the amount of wei for the given address in the state of the
// given block number. The rpc.LatestBlockNumber and rpc.PendingBlockNumber meta
// block numbers are also allowed.
func (s *PublicBlockChainAPI) GetBalance(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*hexutil.Big, error) {
	balance := s.backend.state.GetBalance(address)
	return (*hexutil.Big)(balance), nil
}

// GetBlockByNumber returns the requested block. When blockNr is -1 the chain head is returned. When fullTx is true all
// transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetBlockByNumber(ctx context.Context, blockNr rpc.BlockNumber, fullTx bool) (map[string]interface{}, error) {
	/*
		block, err := s.backend.BlockByNumber(ctx, blockNr)
		if block != nil {
			response, err := s.rpcOutputBlock(block, true, fullTx)
			if err == nil && blockNr == rpc.PendingBlockNumber {
				// Pending blocks need to nil out a few fields
				for _, field := range []string{"hash", "nonce", "miner"} {
					response[field] = nil
				}
			}
			return response, err
		}
		return nil, err
	*/
	return nil, ErrNotImplemented
}

// GetBlockByHash returns the requested block. When fullTx is true all transactions in the block are returned in full
// detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetBlockByHash(ctx context.Context, blockHash common.Hash, fullTx bool) (map[string]interface{}, error) {
	/*
		block, err := s.backend.GetBlock(ctx, blockHash)
		if block != nil {
			return s.rpcOutputBlock(block, true, fullTx)
		}
		return nil, err
	*/
	return nil, ErrNotImplemented
}

// GetUncleByBlockNumberAndIndex returns the uncle block for the given block hash and index. When fullTx is true
// all transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetUncleByBlockNumberAndIndex(ctx context.Context, blockNr rpc.BlockNumber, index hexutil.Uint) (map[string]interface{}, error) {
	/*
		block, err := s.backend.BlockByNumber(ctx, blockNr)
		if block != nil {
			uncles := block.Uncles()
			if index >= hexutil.Uint(len(uncles)) {
				log.Debug("Requested uncle not found", "number", blockNr, "hash", block.Hash(), "index", index)
				return nil, nil
			}
			block = types.NewBlockWithHeader(uncles[index])
			return s.rpcOutputBlock(block, false, false)
		}
		return nil, err
	*/
	return nil, ErrNotImplemented
}

// GetUncleByBlockHashAndIndex returns the uncle block for the given block hash and index. When fullTx is true
// all transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetUncleByBlockHashAndIndex(ctx context.Context, blockHash common.Hash, index hexutil.Uint) (map[string]interface{}, error) {
	/*
		block, err := s.backend.GetBlock(ctx, blockHash)
		if block != nil {
			uncles := block.Uncles()
			if index >= hexutil.Uint(len(uncles)) {
				log.Debug("Requested uncle not found", "number", block.Number(), "hash", blockHash, "index", index)
				return nil, nil
			}
			block = types.NewBlockWithHeader(uncles[index])
			return s.rpcOutputBlock(block, false, false)
		}
		return nil, err
	*/
	return nil, ErrNotImplemented
}

// GetUncleCountByBlockNumber returns number of uncles in the block for the given block number
func (s *PublicBlockChainAPI) GetUncleCountByBlockNumber(ctx context.Context, blockNr rpc.BlockNumber) *hexutil.Uint {
	/*
		if block, _ := s.backend.BlockByNumber(ctx, blockNr); block != nil {
			n := hexutil.Uint(len(block.Uncles()))
			return &n
		}
		return nil
	*/
	return nil
}

// GetUncleCountByBlockHash returns number of uncles in the block for the given block hash
func (s *PublicBlockChainAPI) GetUncleCountByBlockHash(ctx context.Context, blockHash common.Hash) *hexutil.Uint {
	/*
		if block, _ := s.backend.GetBlock(ctx, blockHash); block != nil {
			n := hexutil.Uint(len(block.Uncles()))
			return &n
		}
		return nil
	*/
	return nil
}

// GetCode returns the code stored at the given address in the state for the given block number.
func (s *PublicBlockChainAPI) GetCode(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (hexutil.Bytes, error) {
	/*
		state, _, err := s.backend.StateAndHeaderByNumber(ctx, blockNr)
		if state == nil || err != nil {
			return nil, err
		}
		code := state.GetCode(address)
		return code, state.Error()
	*/
	return nil, ErrNotImplemented
}

// GetStorageAt returns the storage from the state at the given address, key and
// block number. The rpc.LatestBlockNumber and rpc.PendingBlockNumber meta block
// numbers are also allowed.
func (s *PublicBlockChainAPI) GetStorageAt(ctx context.Context, address common.Address, key string, blockNr rpc.BlockNumber) (hexutil.Bytes, error) {
	/*
		state, _, err := s.backend.StateAndHeaderByNumber(ctx, blockNr)
		if state == nil || err != nil {
			return nil, err
		}
		res := state.GetState(address, common.HexToHash(key))
		return res[:], state.Error()
	*/
	return nil, ErrNotImplemented
}

// CallArgs represents the arguments for a call.
type CallArgs struct {
	From     common.Address  `json:"from"`
	To       *common.Address `json:"to"`
	Gas      hexutil.Uint64  `json:"gas"`
	GasPrice hexutil.Big     `json:"gasPrice"`
	Value    hexutil.Big     `json:"value"`
	Data     hexutil.Bytes   `json:"data"`
}

func (s *PublicBlockChainAPI) doCall(ctx context.Context, args CallArgs, blockNr rpc.BlockNumber, vmCfg vm.Config, timeout time.Duration) ([]byte, uint64, bool, error) {
	/*
		defer func(start time.Time) { log.Debug("Executing EVM call finished", "runtime", time.Since(start)) }(time.Now())

		state, header, err := s.backend.StateAndHeaderByNumber(ctx, blockNr)
		if state == nil || err != nil {
			return nil, 0, false, err
		}
		// Set sender address or use a default if none specified
		addr := args.From
		if addr == (common.Address{}) {
			if wallets := s.backend.AccountManager().Wallets(); len(wallets) > 0 {
				if accounts := wallets[0].Accounts(); len(accounts) > 0 {
					addr = accounts[0].Address
				}
			}
		}
		// Set default gas & gas price if none were set
		gas, gasPrice := uint64(args.Gas), args.GasPrice.ToInt()
		if gas == 0 {
			gas = math.MaxUint64 / 2
		}
		if gasPrice.Sign() == 0 {
			gasPrice = new(big.Int).SetUint64(defaultGasPrice)
		}

		// Create new call message
		msg := types.NewMessage(addr, args.To, 0, args.Value.ToInt(), gas, gasPrice, args.Data, false)

		// Setup context so it may be cancelled the call has completed
		// or, in case of unmetered gas, setup a context with a timeout.
		var cancel context.CancelFunc
		if timeout > 0 {
			ctx, cancel = context.WithTimeout(ctx, timeout)
		} else {
			ctx, cancel = context.WithCancel(ctx)
		}
		// Make sure the context is cancelled when the call has completed
		// this makes sure resources are cleaned up.
		defer cancel()

		// Get a new instance of the EVM.
		evm, vmError, err := s.backend.GetEVM(ctx, msg, state, header, vmCfg)
		if err != nil {
			return nil, 0, false, err
		}
		// Wait for the context to be done and cancel the evm. Even if the
		// EVM has finished, cancelling may be done (repeatedly)
		go func() {
			<-ctx.Done()
			evm.Cancel()
		}()

		// Setup the gas pool (also for unmetered requests)
		// and apply the message.
		gp := new(core.GasPool).AddGas(math.MaxUint64)
		res, gas, failed, err := core.ApplyMessage(evm, msg, gp)
		if err := vmError(); err != nil {
			return nil, 0, false, err
		}
		return res, gas, failed, err
	*/
	return nil, 0, false, ErrNotImplemented
}

// Call executes the given transaction on the state for the given block number.
// It doesn't make and changes in the state/blockchain and is useful to execute and retrieve values.
func (s *PublicBlockChainAPI) Call(ctx context.Context, args CallArgs, blockNr rpc.BlockNumber) (hexutil.Bytes, error) {
	result, _, _, err := s.doCall(ctx, args, blockNr, vm.Config{}, 5*time.Second)
	return (hexutil.Bytes)(result), err
}

// EstimateGas returns an estimate of the amount of gas needed to execute the
// given transaction against the current pending block.
func (s *PublicBlockChainAPI) EstimateGas(ctx context.Context, args CallArgs) (hexutil.Uint64, error) {
	/*
		// Binary search the gas requirement, as it may be higher than the amount used
		var (
			lo  uint64 = params.TxGas - 1
			hi  uint64
			cap uint64
		)
		if uint64(args.Gas) >= params.TxGas {
			hi = uint64(args.Gas)
		} else {
			// Retrieve the current pending block to act as the gas ceiling
			block, err := s.backend.BlockByNumber(ctx, rpc.PendingBlockNumber)
			if err != nil {
				return 0, err
			}
			hi = block.GasLimit()
		}
		cap = hi

		// Create a helper to check if a gas allowance results in an executable transaction
		executable := func(gas uint64) bool {
			args.Gas = hexutil.Uint64(gas)

			_, _, failed, err := s.doCall(ctx, args, rpc.PendingBlockNumber, vm.Config{}, 0)
			if err != nil || failed {
				return false
			}
			return true
		}
		// Execute the binary search and hone in on an executable gas limit
		for lo+1 < hi {
			mid := (hi + lo) / 2
			if !executable(mid) {
				lo = mid
			} else {
				hi = mid
			}
		}
		// Reject the transaction as invalid if it still fails at the highest allowance
		if hi == cap {
			if !executable(hi) {
				return 0, fmt.Errorf("gas required exceeds allowance or always failing transaction")
			}
		}
		return hexutil.Uint64(hi), nil
	*/
	return 0, ErrNotImplemented
}

// ExecutionResult groups all structured logs emitted by the EVM
// while replaying a transaction in debug mode as well as transaction
// execution status, the amount of gas used and the return value
type ExecutionResult struct {
	Gas         uint64         `json:"gas"`
	Failed      bool           `json:"failed"`
	ReturnValue string         `json:"returnValue"`
	StructLogs  []StructLogRes `json:"structLogs"`
}

// StructLogRes stores a structured log emitted by the EVM while replaying a
// transaction in debug mode
type StructLogRes struct {
	Pc      uint64             `json:"pc"`
	Op      string             `json:"op"`
	Gas     uint64             `json:"gas"`
	GasCost uint64             `json:"gasCost"`
	Depth   int                `json:"depth"`
	Error   error              `json:"error,omitempty"`
	Stack   *[]string          `json:"stack,omitempty"`
	Memory  *[]string          `json:"memory,omitempty"`
	Storage *map[string]string `json:"storage,omitempty"`
}

// formatLogs formats EVM returned structured logs for json output
func FormatLogs(logs []vm.StructLog) []StructLogRes {
	formatted := make([]StructLogRes, len(logs))
	for index, trace := range logs {
		formatted[index] = StructLogRes{
			Pc:      trace.Pc,
			Op:      trace.Op.String(),
			Gas:     trace.Gas,
			GasCost: trace.GasCost,
			Depth:   trace.Depth,
			Error:   trace.Err,
		}
		if trace.Stack != nil {
			stack := make([]string, len(trace.Stack))
			for i, stackValue := range trace.Stack {
				stack[i] = fmt.Sprintf("%x", math.PaddedBigBytes(stackValue, 32))
			}
			formatted[index].Stack = &stack
		}
		if trace.Memory != nil {
			memory := make([]string, 0, (len(trace.Memory)+31)/32)
			for i := 0; i+32 <= len(trace.Memory); i += 32 {
				memory = append(memory, fmt.Sprintf("%x", trace.Memory[i:i+32]))
			}
			formatted[index].Memory = &memory
		}
		if trace.Storage != nil {
			storage := make(map[string]string)
			for i, storageValue := range trace.Storage {
				storage[fmt.Sprintf("%x", i)] = fmt.Sprintf("%x", storageValue)
			}
			formatted[index].Storage = &storage
		}
	}
	return formatted
}

// RPCMarshalBlock converts the given block to the RPC output which depends on fullTx. If inclTx is true transactions are
// returned. When fullTx is true the returned block contains full transaction details, otherwise it will only contain
// transaction hashes.
func RPCMarshalBlock(b *types.Block, inclTx bool, fullTx bool) (map[string]interface{}, error) {
	head := b.Header() // copies the header once
	fields := map[string]interface{}{
		"number":           (*hexutil.Big)(head.Number),
		"hash":             b.Hash(),
		"parentHash":       head.ParentHash,
		"nonce":            head.Nonce,
		"mixHash":          head.MixDigest,
		"sha3Uncles":       head.UncleHash,
		"logsBloom":        head.Bloom,
		"stateRoot":        head.Root,
		"miner":            head.Coinbase,
		"difficulty":       (*hexutil.Big)(head.Difficulty),
		"extraData":        hexutil.Bytes(head.Extra),
		"size":             hexutil.Uint64(b.Size()),
		"gasLimit":         hexutil.Uint64(head.GasLimit),
		"gasUsed":          hexutil.Uint64(head.GasUsed),
		"timestamp":        (*hexutil.Big)(head.Time),
		"transactionsRoot": head.TxHash,
		"receiptsRoot":     head.ReceiptHash,
	}

	if inclTx {
		formatTx := func(tx *types.Transaction) (interface{}, error) {
			return tx.Hash(), nil
		}
		if fullTx {
			formatTx = func(tx *types.Transaction) (interface{}, error) {
				return newRPCTransactionFromBlockHash(b, tx.Hash()), nil
			}
		}
		txs := b.Transactions()
		transactions := make([]interface{}, len(txs))
		var err error
		for i, tx := range txs {
			if transactions[i], err = formatTx(tx); err != nil {
				return nil, err
			}
		}
		fields["transactions"] = transactions
	}

	uncles := b.Uncles()
	uncleHashes := make([]common.Hash, len(uncles))
	for i, uncle := range uncles {
		uncleHashes[i] = uncle.Hash()
	}
	fields["uncles"] = uncleHashes

	return fields, nil
}

// rpcOutputBlock uses the generalized output filler, then adds the total difficulty field, which requires
// a `PublicBlockchainAPI`.
func (s *PublicBlockChainAPI) rpcOutputBlock(b *types.Block, inclTx bool, fullTx bool) (map[string]interface{}, error) {
	/*
		fields, err := RPCMarshalBlock(b, inclTx, fullTx)
		if err != nil {
			return nil, err
		}
		fields["totalDifficulty"] = (*hexutil.Big)(s.backend.GetTd(b.Hash()))
		return fields, err
	*/
	return nil, ErrNotImplemented
}

// RPCTransaction represents a transaction that will serialize to the RPC representation of a transaction
type RPCTransaction struct {
	BlockHash        common.Hash     `json:"blockHash"`
	BlockNumber      *hexutil.Big    `json:"blockNumber"`
	From             common.Address  `json:"from"`
	Gas              hexutil.Uint64  `json:"gas"`
	GasPrice         *hexutil.Big    `json:"gasPrice"`
	Hash             common.Hash     `json:"hash"`
	Input            hexutil.Bytes   `json:"input"`
	Nonce            hexutil.Uint64  `json:"nonce"`
	To               *common.Address `json:"to"`
	TransactionIndex hexutil.Uint    `json:"transactionIndex"`
	Value            *hexutil.Big    `json:"value"`
	V                *hexutil.Big    `json:"v"`
	R                *hexutil.Big    `json:"r"`
	S                *hexutil.Big    `json:"s"`
}

// newRPCTransaction returns a transaction that will serialize to the RPC
// representation, with the given location metadata set (if available).
func newRPCTransaction(tx *types.Transaction, blockHash common.Hash, blockNumber uint64, index uint64) *RPCTransaction {
	var signer types.Signer = types.FrontierSigner{}
	if tx.Protected() {
		signer = types.NewEIP155Signer(tx.ChainId())
	}
	from, _ := types.Sender(signer, tx)
	v, r, s := tx.RawSignatureValues()

	result := &RPCTransaction{
		From:     from,
		Gas:      hexutil.Uint64(tx.Gas()),
		GasPrice: (*hexutil.Big)(tx.GasPrice()),
		Hash:     tx.Hash(),
		Input:    hexutil.Bytes(tx.Data()),
		Nonce:    hexutil.Uint64(tx.Nonce()),
		To:       tx.To(),
		Value:    (*hexutil.Big)(tx.Value()),
		V:        (*hexutil.Big)(v),
		R:        (*hexutil.Big)(r),
		S:        (*hexutil.Big)(s),
	}
	if blockHash != (common.Hash{}) {
		result.BlockHash = blockHash
		result.BlockNumber = (*hexutil.Big)(new(big.Int).SetUint64(blockNumber))
		result.TransactionIndex = hexutil.Uint(index)
	}
	return result
}

// newRPCPendingTransaction returns a pending transaction that will serialize to the RPC representation
func newRPCPendingTransaction(tx *types.Transaction) *RPCTransaction {
	return newRPCTransaction(tx, common.Hash{}, 0, 0)
}

// newRPCTransactionFromBlockIndex returns a transaction that will serialize to the RPC representation.
func newRPCTransactionFromBlockIndex(b *types.Block, index uint64) *RPCTransaction {
	txs := b.Transactions()
	if index >= uint64(len(txs)) {
		return nil
	}
	return newRPCTransaction(txs[index], b.Hash(), b.NumberU64(), index)
}

// newRPCRawTransactionFromBlockIndex returns the bytes of a transaction given a block and a transaction index.
func newRPCRawTransactionFromBlockIndex(b *types.Block, index uint64) hexutil.Bytes {
	txs := b.Transactions()
	if index >= uint64(len(txs)) {
		return nil
	}
	blob, _ := rlp.EncodeToBytes(txs[index])
	return blob
}

// newRPCTransactionFromBlockHash returns a transaction that will serialize to the RPC representation.
func newRPCTransactionFromBlockHash(b *types.Block, hash common.Hash) *RPCTransaction {
	for idx, tx := range b.Transactions() {
		if tx.Hash() == hash {
			return newRPCTransactionFromBlockIndex(b, uint64(idx))
		}
	}
	return nil
}

// PublicTransactionPoolAPI exposes methods for the RPC interface
type PublicTransactionPoolAPI struct {
	backend   *Service
	nonceLock *AddrLocker
}

// NewPublicTransactionPoolAPI creates a new RPC service with methods specific for the transaction pool.
func NewPublicTransactionPoolAPI(b *Service, nonceLock *AddrLocker) *PublicTransactionPoolAPI {
	return &PublicTransactionPoolAPI{b, nonceLock}
}

// GetBlockTransactionCountByNumber returns the number of transactions in the block with the given block number.
func (s *PublicTransactionPoolAPI) GetBlockTransactionCountByNumber(ctx context.Context, blockNr rpc.BlockNumber) *hexutil.Uint {
	/*
		if block, _ := s.backend.BlockByNumber(ctx, blockNr); block != nil {
			n := hexutil.Uint(len(block.Transactions()))
			return &n
		}
		return nil
	*/
	return nil
}

// GetBlockTransactionCountByHash returns the number of transactions in the block with the given hash.
func (s *PublicTransactionPoolAPI) GetBlockTransactionCountByHash(ctx context.Context, blockHash common.Hash) *hexutil.Uint {
	/*
		if block, _ := s.backend.GetBlock(ctx, blockHash); block != nil {
			n := hexutil.Uint(len(block.Transactions()))
			return &n
		}
		return nil
	*/
	return nil
}

// GetTransactionByBlockNumberAndIndex returns the transaction for the given block number and index.
func (s *PublicTransactionPoolAPI) GetTransactionByBlockNumberAndIndex(ctx context.Context, blockNr rpc.BlockNumber, index hexutil.Uint) *RPCTransaction {
	/*
		if block, _ := s.backend.BlockByNumber(ctx, blockNr); block != nil {
			return newRPCTransactionFromBlockIndex(block, uint64(index))
		}
		return nil
	*/
	return nil
}

// GetTransactionByBlockHashAndIndex returns the transaction for the given block hash and index.
func (s *PublicTransactionPoolAPI) GetTransactionByBlockHashAndIndex(ctx context.Context, blockHash common.Hash, index hexutil.Uint) *RPCTransaction {
	/*
		if block, _ := s.backend.GetBlock(ctx, blockHash); block != nil {
			return newRPCTransactionFromBlockIndex(block, uint64(index))
		}
		return nil
	*/
	return nil
}

// GetRawTransactionByBlockNumberAndIndex returns the bytes of the transaction for the given block number and index.
func (s *PublicTransactionPoolAPI) GetRawTransactionByBlockNumberAndIndex(ctx context.Context, blockNr rpc.BlockNumber, index hexutil.Uint) hexutil.Bytes {
	/*
		if block, _ := s.backend.BlockByNumber(ctx, blockNr); block != nil {
			return newRPCRawTransactionFromBlockIndex(block, uint64(index))
		}
		return nil
	*/
	return nil
}

// GetRawTransactionByBlockHashAndIndex returns the bytes of the transaction for the given block hash and index.
func (s *PublicTransactionPoolAPI) GetRawTransactionByBlockHashAndIndex(ctx context.Context, blockHash common.Hash, index hexutil.Uint) hexutil.Bytes {
	/*
		if block, _ := s.backend.GetBlock(ctx, blockHash); block != nil {
			return newRPCRawTransactionFromBlockIndex(block, uint64(index))
		}
		return nil
	*/
	return nil
}

// GetTransactionCount returns the number of transactions the given address has sent for the given block number
func (s *PublicTransactionPoolAPI) GetTransactionCount(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*hexutil.Uint64, error) {
	/*
		state, _, err := s.backend.StateAndHeaderByNumber(ctx, blockNr)
		if state == nil || err != nil {
			return nil, err
		}
		nonce := state.GetNonce(address)
		return (*hexutil.Uint64)(&nonce), state.Error()
	*/
	return nil, ErrNotImplemented
}

// GetTransactionByHash returns the transaction for the given hash
func (s *PublicTransactionPoolAPI) GetTransactionByHash(ctx context.Context, hash common.Hash) *RPCTransaction {
	/*
		// Try to return an already finalized transaction
		if tx, blockHash, blockNumber, index := rawdb.ReadTransaction(s.backend.ChainDb(), hash); tx != nil {
			return newRPCTransaction(tx, blockHash, blockNumber, index)
		}
		// No finalized transaction, try to retrieve it from the pool
		if tx := s.backend.GetPoolTransaction(hash); tx != nil {
			return newRPCPendingTransaction(tx)
		}
		// Transaction unknown, return as such
		return nil
	*/
	return nil
}

// GetRawTransactionByHash returns the bytes of the transaction for the given hash.
func (s *PublicTransactionPoolAPI) GetRawTransactionByHash(ctx context.Context, hash common.Hash) (hexutil.Bytes, error) {
	/*
		var tx *types.Transaction

		// Retrieve a finalized transaction, or a pooled otherwise
		if tx, _, _, _ = rawdb.ReadTransaction(s.backend.ChainDb(), hash); tx == nil {
			if tx = s.backend.GetPoolTransaction(hash); tx == nil {
				// Transaction not found anywhere, abort
				return nil, nil
			}
		}
		// Serialize to RLP and return
		return rlp.EncodeToBytes(tx)
	*/
	return nil, ErrNotImplemented
}

// GetTransactionReceipt returns the transaction receipt for the given transaction hash.
func (s *PublicTransactionPoolAPI) GetTransactionReceipt(ctx context.Context, hash common.Hash) (map[string]interface{}, error) {
	/*
		tx, blockHash, blockNumber, index := rawdb.ReadTransaction(s.backend.ChainDb(), hash)
		if tx == nil {
			return nil, nil
		}
		receipts, err := s.backend.GetReceipts(ctx, blockHash)
		if err != nil {
			return nil, err
		}
		if len(receipts) <= int(index) {
			return nil, nil
		}
		receipt := receipts[index]

		var signer types.Signer = types.FrontierSigner{}
		if tx.Protected() {
			signer = types.NewEIP155Signer(tx.ChainId())
		}
		from, _ := types.Sender(signer, tx)

		fields := map[string]interface{}{
			"blockHash":         blockHash,
			"blockNumber":       hexutil.Uint64(blockNumber),
			"transactionHash":   hash,
			"transactionIndex":  hexutil.Uint64(index),
			"from":              from,
			"to":                tx.To(),
			"gasUsed":           hexutil.Uint64(receipt.GasUsed),
			"cumulativeGasUsed": hexutil.Uint64(receipt.CumulativeGasUsed),
			"contractAddress":   nil,
			"logs":              receipt.Logs,
			"logsBloom":         receipt.Bloom,
		}

		// Assign receipt status or post state.
		if len(receipt.PostState) > 0 {
			fields["root"] = hexutil.Bytes(receipt.PostState)
		} else {
			fields["status"] = hexutil.Uint(receipt.Status)
		}
		if receipt.Logs == nil {
			fields["logs"] = [][]*types.Log{}
		}
		// If the ContractAddress is 20 0x0 bytes, assume it is not a contract creation
		if receipt.ContractAddress != (common.Address{}) {
			fields["contractAddress"] = receipt.ContractAddress
		}
		return fields, nil
	*/
	return nil, ErrNotImplemented
}

// sign is a helper function that signs a transaction with the private key of the given address.
func (s *PublicTransactionPoolAPI) sign(addr common.Address, tx *types.Transaction) (*types.Transaction, error) {
	// Look up the wallet containing the requested signer
	account := accounts.Account{Address: addr}

	wallet, err := s.backend.AccountManager().Find(account)
	if err != nil {
		return nil, err
	}
	// Request the wallet to sign the transaction
	chainID := s.backend.chainConfig.ChainID
	return wallet.SignTx(account, tx, chainID)

}

// SendTxArgs represents the arguments to sumbit a new transaction into the transaction pool.
type SendTxArgs struct {
	From     common.Address  `json:"from"`
	To       *common.Address `json:"to"`
	Gas      *hexutil.Uint64 `json:"gas"`
	GasPrice *hexutil.Big    `json:"gasPrice"`
	Value    *hexutil.Big    `json:"value"`
	Nonce    *hexutil.Uint64 `json:"nonce"`
	// We accept "data" and "input" for backwards-compatibility reasons. "input" is the
	// newer name and should be preferred by clients.
	Data  *hexutil.Bytes `json:"data"`
	Input *hexutil.Bytes `json:"input"`
}

// setDefaults is a helper function that fills in default values for unspecified tx fields.
func (args *SendTxArgs) setDefaults(ctx context.Context, b *Service) error {
	if args.Gas == nil {
		args.Gas = new(hexutil.Uint64)
		*(*uint64)(args.Gas) = 90000
	}
	if args.GasPrice == nil {
		*args.GasPrice = hexutil.Big(*defaultGasPrice)
	}
	if args.Value == nil {
		args.Value = new(hexutil.Big)
	}
	if args.Nonce == nil {
		*args.Nonce = hexutil.Uint64(b.state.GetPoolNonce(args.From))
	}
	if args.Data != nil && args.Input != nil && !bytes.Equal(*args.Data, *args.Input) {
		return errors.New(
			`both "data" and "input" are set and not equal. Please use "input" to pass transaction call data`)
	}
	if args.To == nil {
		// Contract creation
		var input []byte
		if args.Data != nil {
			input = *args.Data
		} else if args.Input != nil {
			input = *args.Input
		}
		if len(input) == 0 {
			return errors.New(`contract creation without any data provided`)
		}
	}
	return nil
}

func (args *SendTxArgs) toTransaction() *types.Transaction {
	var input []byte
	if args.Data != nil {
		input = *args.Data
	} else if args.Input != nil {
		input = *args.Input
	}
	if args.To == nil {
		return types.NewContractCreation(uint64(*args.Nonce), (*big.Int)(args.Value), uint64(*args.Gas), (*big.Int)(args.GasPrice), input)
	}
	return types.NewTransaction(uint64(*args.Nonce), *args.To, (*big.Int)(args.Value), uint64(*args.Gas), (*big.Int)(args.GasPrice), input)
}

// submitTransaction is a helper function that submits tx to txPool and logs a message.
func submitTransaction(ctx context.Context, b *Service, tx *types.Transaction) (common.Hash, error) {
	if tx.To() == nil {
		signer := types.MakeSigner(b.ChainConfig(), big.NewInt(b.state.GetBlockIndex()))
		from, err := types.Sender(signer, tx)
		if err != nil {
			return common.Hash{}, err
		}
		addr := crypto.CreateAddress(from, tx.Nonce())
		log.Info("Submitted contract creation", "fullhash", tx.Hash().Hex(), "contract", addr.Hex())
	} else {
		log.Info("Submitted transaction", "fullhash", tx.Hash().Hex(), "recipient", tx.To())
	}

	raw, err := tx.MarshalJSON()
	if err != nil {
		return common.Hash{}, err
	}
	b.submitCh <- raw

	return tx.Hash(), nil
}

// SendTransaction creates a transaction for the given argument, sign it and submit it to the
// transaction pool.
func (s *PublicTransactionPoolAPI) SendTransaction(ctx context.Context, args SendTxArgs) (common.Hash, error) {
	// Look up the wallet containing the requested signer
	account := accounts.Account{Address: args.From}

	wallet, err := s.backend.AccountManager().Find(account)
	if err != nil {
		return common.Hash{}, err
	}

	if args.Nonce == nil {
		// Hold the addresse's mutex around signing to prevent concurrent assignment of
		// the same nonce to multiple accounts.
		s.nonceLock.LockAddr(args.From)
		defer s.nonceLock.UnlockAddr(args.From)
	}

	// Set some sanity defaults and terminate on failure
	if err := args.setDefaults(ctx, s.backend); err != nil {
		return common.Hash{}, err
	}
	// Assemble the transaction and sign with the wallet
	tx := args.toTransaction()

	chainID := s.backend.chainConfig.ChainID

	signed, err := wallet.SignTx(account, tx, chainID)
	if err != nil {
		return common.Hash{}, err
	}
	return submitTransaction(ctx, s.backend, signed)

}

// SendRawTransaction will add the signed transaction to the transaction pool.
// The sender is responsible for signing the transaction and using the correct nonce.
func (s *PublicTransactionPoolAPI) SendRawTransaction(ctx context.Context, encodedTx hexutil.Bytes) (common.Hash, error) {
	tx := new(types.Transaction)
	if err := rlp.DecodeBytes(encodedTx, tx); err != nil {
		return common.Hash{}, err
	}
	return submitTransaction(ctx, s.backend, tx)
}

// Sign calculates an ECDSA signature for:
// keccack256("\x19Ethereum Signed Message:\n" + len(message) + message).
//
// Note, the produced signature conforms to the secp256k1 curve R, S and V values,
// where the V value will be 27 or 28 for legacy reasons.
//
// The account associated with addr must be unlocked.
//
// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_sign
func (s *PublicTransactionPoolAPI) Sign(addr common.Address, data hexutil.Bytes) (hexutil.Bytes, error) {
	// Look up the wallet containing the requested signer
	account := accounts.Account{Address: addr}

	wallet, err := s.backend.AccountManager().Find(account)
	if err != nil {
		return nil, err
	}
	// Sign the requested hash with the wallet
	signature, err := wallet.SignHash(account, signHash(data))
	if err == nil {
		signature[64] += 27 // Transform V from 0/1 to 27/28 according to the yellow paper
	}
	return signature, err
}

// SignTransactionResult represents a RLP encoded signed transaction.
type SignTransactionResult struct {
	Raw hexutil.Bytes      `json:"raw"`
	Tx  *types.Transaction `json:"tx"`
}

// SignTransaction will sign the given transaction with the from account.
// The node needs to have the private key of the account corresponding with
// the given from address and it needs to be unlocked.
func (s *PublicTransactionPoolAPI) SignTransaction(ctx context.Context, args SendTxArgs) (*SignTransactionResult, error) {

	if args.Gas == nil {
		return nil, fmt.Errorf("gas not specified")
	}
	if args.GasPrice == nil {
		return nil, fmt.Errorf("gasPrice not specified")
	}
	if args.Nonce == nil {
		return nil, fmt.Errorf("nonce not specified")
	}
	if err := args.setDefaults(ctx, s.backend); err != nil {
		return nil, err
	}
	tx, err := s.sign(args.From, args.toTransaction())
	if err != nil {
		return nil, err
	}
	data, err := rlp.EncodeToBytes(tx)
	if err != nil {
		return nil, err
	}
	return &SignTransactionResult{data, tx}, nil
}

// PendingTransactions returns the transactions that are in the transaction pool
// and have a from address that is one of the accounts this node manages.
func (s *PublicTransactionPoolAPI) PendingTransactions() ([]*RPCTransaction, error) {
	/*
		pending, err := s.backend.GetPoolTransactions()
		if err != nil {
			return nil, err
		}
		accounts := make(map[common.Address]struct{})
		for _, wallet := range s.backend.AccountManager().Wallets() {
			for _, account := range wallet.Accounts() {
				accounts[account.Address] = struct{}{}
			}
		}
		transactions := make([]*RPCTransaction, 0, len(pending))
		for _, tx := range pending {
			var signer types.Signer = types.HomesteadSigner{}
			if tx.Protected() {
				signer = types.NewEIP155Signer(tx.ChainId())
			}
			from, _ := types.Sender(signer, tx)
			if _, exists := accounts[from]; exists {
				transactions = append(transactions, newRPCPendingTransaction(tx))
			}
		}
		return transactions, nil
	*/
	return nil, ErrNotImplemented
}

// Resend accepts an existing transaction and a new gas price and limit. It will remove
// the given transaction from the pool and reinsert it with the new gas price and limit.
func (s *PublicTransactionPoolAPI) Resend(ctx context.Context, sendArgs SendTxArgs, gasPrice *hexutil.Big, gasLimit *hexutil.Uint64) (common.Hash, error) {
	/*
		if sendArgs.Nonce == nil {
			return common.Hash{}, fmt.Errorf("missing transaction nonce in transaction spec")
		}
		if err := sendArgs.setDefaults(ctx, s.backend); err != nil {
			return common.Hash{}, err
		}
		matchTx := sendArgs.toTransaction()
		pending, err := s.backend.GetPoolTransactions()
		if err != nil {
			return common.Hash{}, err
		}

		for _, p := range pending {
			var signer types.Signer = types.HomesteadSigner{}
			if p.Protected() {
				signer = types.NewEIP155Signer(p.ChainId())
			}
			wantSigHash := signer.Hash(matchTx)

			if pFrom, err := types.Sender(signer, p); err == nil && pFrom == sendArgs.From && signer.Hash(p) == wantSigHash {
				// Match. Re-sign and send the transaction.
				if gasPrice != nil && (*big.Int)(gasPrice).Sign() != 0 {
					sendArgs.GasPrice = gasPrice
				}
				if gasLimit != nil && *gasLimit != 0 {
					sendArgs.Gas = gasLimit
				}
				signedTx, err := s.sign(sendArgs.From, sendArgs.toTransaction())
				if err != nil {
					return common.Hash{}, err
				}
				if err = s.backend.SendTx(ctx, signedTx); err != nil {
					return common.Hash{}, err
				}
				return signedTx.Hash(), nil
			}
		}

		return common.Hash{}, fmt.Errorf("Transaction %#x not found", matchTx.Hash())
	*/
	return common.Hash{}, ErrNotImplemented
}

// PublicDebugAPI is the collection of Ethereum APIs exposed over the public
// debugging endpoint.
type PublicDebugAPI struct {
	backend *Service
}

// NewPublicDebugAPI creates a new API definition for the public debug methods
// of the Ethereum service.
func NewPublicDebugAPI(b *Service) *PublicDebugAPI {
	return &PublicDebugAPI{backend: b}
}

// GetBlockRlp retrieves the RLP encoded for of a single block.
func (api *PublicDebugAPI) GetBlockRlp(ctx context.Context, number uint64) (string, error) {
	/*
		block, _ := api.backend.BlockByNumber(ctx, rpc.BlockNumber(number))
		if block == nil {
			return "", fmt.Errorf("block #%d not found", number)
		}
		encoded, err := rlp.EncodeToBytes(block)
		if err != nil {
			return "", err
		}
		return fmt.Sprintf("%x", encoded), nil
	*/
	return "", ErrNotImplemented
}

// PrintBlock retrieves a block and returns its pretty printed form.
func (api *PublicDebugAPI) PrintBlock(ctx context.Context, number uint64) (string, error) {
	/*
		block, _ := api.backend.BlockByNumber(ctx, rpc.BlockNumber(number))
		if block == nil {
			return "", fmt.Errorf("block #%d not found", number)
		}
		return spew.Sdump(block), nil
	*/
	return "", ErrNotImplemented
}

// SeedHash retrieves the seed hash of a block.
func (api *PublicDebugAPI) SeedHash(ctx context.Context, number uint64) (string, error) {
	/*
		block, _ := api.backend.BlockByNumber(ctx, rpc.BlockNumber(number))
		if block == nil {
			return "", fmt.Errorf("block #%d not found", number)
		}
		return fmt.Sprintf("0x%x", ethash.SeedHash(number)), nil
	*/
	return "", ErrNotImplemented
}

// PrivateDebugAPI is the collection of Ethereum APIs exposed over the private
// debugging endpoint.
type PrivateDebugAPI struct {
	backend *Service
}

// NewPrivateDebugAPI creates a new API definition for the private debug methods
// of the Ethereum service.
func NewPrivateDebugAPI(b *Service) *PrivateDebugAPI {
	return &PrivateDebugAPI{backend: b}
}

// ChaindbProperty returns leveldb properties of the chain database.
func (api *PrivateDebugAPI) ChaindbProperty(property string) (string, error) {
	/*
		ldb, ok := api.backend.ChainDb().(interface {
			LDB() *leveldb.DB
		})
		if !ok {
			return "", fmt.Errorf("chaindbProperty does not work for memory databases")
		}
		if property == "" {
			property = "leveldb.stats"
		} else if !strings.HasPrefix(property, "leveldb.") {
			property = "leveldb." + property
		}
		return ldb.LDB().GetProperty(property)
	*/
	return "", ErrNotImplemented
}

func (api *PrivateDebugAPI) ChaindbCompact() error {
	/*
		ldb, ok := api.backend.ChainDb().(interface {
			LDB() *leveldb.DB
		})
		if !ok {
			return fmt.Errorf("chaindbCompact does not work for memory databases")
		}
		for b := byte(0); b < 255; b++ {
			log.Info("Compacting chain database", "range", fmt.Sprintf("0x%0.2X-0x%0.2X", b, b+1))
			err := ldb.LDB().CompactRange(util.Range{Start: []byte{b}, Limit: []byte{b + 1}})
			if err != nil {
				log.Error("Database compaction failed", "err", err)
				return err
			}
		}
		return nil
	*/
	return ErrNotImplemented
}

// SetHead rewinds the head of the blockchain to a previous block.
func (api *PrivateDebugAPI) SetHead(number hexutil.Uint64) {
	/*
		api.backend.SetHead(uint64(number))
	*/
}

// PublicNetAPI offers network related RPC methods
type PublicNetAPI struct {
	net            *p2p.Server
	networkVersion uint64
}

// NewPublicNetAPI creates a new net API instance.
func NewPublicNetAPI(net *p2p.Server, networkVersion uint64) *PublicNetAPI {
	return &PublicNetAPI{net, networkVersion}
}

// Listening returns an indication if the node is listening for network connections.
func (s *PublicNetAPI) Listening() bool {
	return true // always listening
}

// PeerCount returns the number of connected peers
func (s *PublicNetAPI) PeerCount() hexutil.Uint {
	return hexutil.Uint(s.net.PeerCount())
}

// Version returns the current ethereum protocol version.
func (s *PublicNetAPI) Version() string {
	return fmt.Sprintf("%d", s.networkVersion)
}