func (self *Registrar) SetHashReg(hashreg string, addr common.Address) (txhash string, err error) {
	if hashreg != "" {
		HashRegAddr = hashreg
	} else {
		if !zero.MatchString(HashRegAddr) {
			return
		}
		nameHex, extra := encodeName(HashRegName, 2)
		hashRegAbi := resolveAbi + nameHex + extra
		glog.V(logger.Detail).Infof("\ncall HashRegAddr %v with %v\n", GlobalRegistrarAddr, hashRegAbi)
		var res string
		res, _, err = self.backend.Call("", GlobalRegistrarAddr, "", "", "", hashRegAbi)
		if len(res) >= 40 {
			HashRegAddr = "0x" + res[len(res)-40:len(res)]
		}
		if err != nil || zero.MatchString(HashRegAddr) {
			if (addr == common.Address{}) {
				err = fmt.Errorf("HashReg address not found and sender for creation not given")
				return
			}

			txhash, err = self.backend.Transact(addr.Hex(), "", "", "", "", "", HashRegCode)
			if err != nil {
				err = fmt.Errorf("HashReg address not found and sender for creation failed: %v", err)
			}
			glog.V(logger.Detail).Infof("created HashRegAddr @ txhash %v\n", txhash)
		} else {
			glog.V(logger.Detail).Infof("HashRegAddr found at @ %v\n", HashRegAddr)
			return
		}
	}

	return
}

func (self *Registrar) SetUrlHint(urlhint string, addr common.Address) (txhash string, err error) {
	if urlhint != "" {
		UrlHintAddr = urlhint
	} else {
		if !zero.MatchString(UrlHintAddr) {
			return
		}
		nameHex, extra := encodeName(UrlHintName, 2)
		urlHintAbi := resolveAbi + nameHex + extra
		glog.V(logger.Detail).Infof("UrlHint address query data: %s to %s", urlHintAbi, GlobalRegistrarAddr)
		var res string
		res, _, err = self.backend.Call("", GlobalRegistrarAddr, "", "", "", urlHintAbi)
		if len(res) >= 40 {
			UrlHintAddr = "0x" + res[len(res)-40:len(res)]
		}
		if err != nil || zero.MatchString(UrlHintAddr) {
			if (addr == common.Address{}) {
				err = fmt.Errorf("UrlHint address not found and sender for creation not given")
				return
			}
			txhash, err = self.backend.Transact(addr.Hex(), "", "", "", "210000", "", UrlHintCode)
			if err != nil {
				err = fmt.Errorf("UrlHint address not found and sender for creation failed: %v", err)
			}
			glog.V(logger.Detail).Infof("created UrlHint @ txhash %v\n", txhash)
		} else {
			glog.V(logger.Detail).Infof("UrlHint found @ %v\n", HashRegAddr)
			return
		}
	}

	return
}

func opCreate(instr instruction, pc *uint64, env Environment, contract *Contract, memory *Memory, stack *stack) {
	var (
		value        = stack.pop()
		offset, size = stack.pop(), stack.pop()
		input        = memory.Get(offset.Int64(), size.Int64())
		gas          = new(big.Int).Set(contract.Gas)
		addr         common.Address
		ret          []byte
		suberr       error
	)

	contract.UseGas(contract.Gas)
	ret, addr, suberr = env.Create(contract, input, gas, contract.Price, value)
	if suberr != nil {
		stack.push(new(big.Int))
	} else {
		// gas < len(ret) * Createinstr.dataGas == NO_CODE
		dataGas := big.NewInt(int64(len(ret)))
		dataGas.Mul(dataGas, params.CreateDataGas)
		if contract.UseGas(dataGas) {
			env.Db().SetCode(addr, ret)
		}

		stack.push(addr.Big())

	}
}

// SetNonce sets the new canonical nonce for the managed state
func (ms *ManagedState) SetNonce(addr common.Address, nonce uint64) {
	ms.mu.Lock()
	defer ms.mu.Unlock()

	so := ms.GetOrNewStateObject(addr)
	so.SetNonce(nonce)

	ms.accounts[addr.Str()] = newAccount(so)
}

// Start Go API. Not important for this version
func (c *Channels) NewChannel(key *ecdsa.PrivateKey, to common.Address, amount, price *big.Int, cb func(*Channel)) (*types.Transaction, error) {
	from := crypto.PubkeyToAddress(key.PublicKey)

	data, err := c.abi.Pack("createChannel", to, price)
	if err != nil {
		return nil, err
	}

	statedb, err := c.blockchain.State()
	if err != nil {
		return nil, err
	}

	transaction, err := types.NewTransaction(statedb.GetNonce(from), contractAddress, amount, big.NewInt(250000), big.NewInt(50000000000), data).SignECDSA(key)
	if err != nil {
		return nil, err
	}

	evId := c.abi.Events["NewChannel"].Id()
	filter := filters.New(c.db)
	filter.SetAddresses([]common.Address{contractAddress})
	filter.SetTopics([][]common.Hash{ // TODO refactor, helper
		[]common.Hash{evId},
		[]common.Hash{from.Hash()},
		[]common.Hash{to.Hash()},
	})
	filter.SetBeginBlock(0)
	filter.SetEndBlock(-1)
	filter.LogsCallback = func(logs vm.Logs) {
		// tere should really be only one log. TODO this part
		log := logs[0]

		// TODO: do to and from validation here
		/*
			from := log.Topics[1]
			to := log.Topics[2]
		*/
		channelId := common.BytesToHash(log.Data[0:31])
		nonce := common.BytesToBig(log.Data[31:])

		c.channelMu.Lock()
		defer c.channelMu.Unlock()

		channel, exist := c.channels[channelId]
		if !exist {
			channel = NewChannel(c, channelId, from, to, nonce)
			c.channels[channelId] = channel
		}
		cb(channel)
	}

	c.filters.Add(filter)

	return transaction, nil
}

// called as first step in the registration process on HashReg
func (self *Registrar) SetOwner(address common.Address) (txh string, err error) {
	if zero.MatchString(HashRegAddr) {
		return "", fmt.Errorf("HashReg address is not set")
	}
	return self.backend.Transact(
		address.Hex(),
		HashRegAddr,
		"", "", "", "",
		setOwnerAbi,
	)
}

// NewStateObject create a state object whether it exist in the trie or not
func (self *StateDB) newStateObject(addr common.Address) *StateObject {
	if glog.V(logger.Core) {
		glog.Infof("(+) %x\n", addr)
	}

	stateObject := NewStateObject(addr, self.db)
	stateObject.SetNonce(StartingNonce)
	self.stateObjects[addr.Str()] = stateObject

	return stateObject
}

// ReserveName(from, name) reserves name for the sender address in the globalRegistrar
// the tx needs to be mined to take effect
func (self *Registrar) ReserveName(address common.Address, name string) (txh string, err error) {
	if zero.MatchString(GlobalRegistrarAddr) {
		return "", fmt.Errorf("GlobalRegistrar address is not set")
	}
	nameHex, extra := encodeName(name, 2)
	abi := reserveAbi + nameHex + extra
	glog.V(logger.Detail).Infof("Reserve data: %s", abi)
	return self.backend.Transact(
		address.Hex(),
		GlobalRegistrarAddr,
		"", "", "", "",
		abi,
	)
}

// populate the managed state
func (ms *ManagedState) getAccount(addr common.Address) *account {
	straddr := addr.Str()
	if account, ok := ms.accounts[straddr]; !ok {
		so := ms.GetOrNewStateObject(addr)
		ms.accounts[straddr] = newAccount(so)
	} else {
		// Always make sure the state account nonce isn't actually higher
		// than the tracked one.
		so := ms.StateDB.GetStateObject(addr)
		if so != nil && uint64(len(account.nonces))+account.nstart < so.nonce {
			ms.accounts[straddr] = newAccount(so)
		}

	}

	return ms.accounts[straddr]
}

// SetAddressToName(from, name, addr) will set the Address to address for name
// in the globalRegistrar using from as the sender of the transaction
// the tx needs to be mined to take effect
func (self *Registrar) SetAddressToName(from common.Address, name string, address common.Address) (txh string, err error) {
	if zero.MatchString(GlobalRegistrarAddr) {
		return "", fmt.Errorf("GlobalRegistrar address is not set")
	}

	nameHex, extra := encodeName(name, 6)
	addrHex := encodeAddress(address)

	abi := registerAbi + nameHex + addrHex + trueHex + extra
	glog.V(logger.Detail).Infof("SetAddressToName data: %s to %s ", abi, GlobalRegistrarAddr)

	return self.backend.Transact(
		from.Hex(),
		GlobalRegistrarAddr,
		"", "", "", "",
		abi,
	)
}

func (self *Registrar) SetGlobalRegistrar(namereg string, addr common.Address) (txhash string, err error) {
	if namereg != "" {
		GlobalRegistrarAddr = namereg
		return
	}
	if zero.MatchString(GlobalRegistrarAddr) {
		if (addr == common.Address{}) {
			err = fmt.Errorf("GlobalRegistrar address not found and sender for creation not given")
			return
		} else {
			txhash, err = self.backend.Transact(addr.Hex(), "", "", "", "800000", "", GlobalRegistrarCode)
			if err != nil {
				err = fmt.Errorf("GlobalRegistrar address not found and sender for creation failed: %v", err)
				return
			}
		}
	}
	return
}

// NameToAddr(from, name) queries the registrar for the address on name
func (self *Registrar) NameToAddr(from common.Address, name string) (address common.Address, err error) {
	if zero.MatchString(GlobalRegistrarAddr) {
		return address, fmt.Errorf("GlobalRegistrar address is not set")
	}

	nameHex, extra := encodeName(name, 2)
	abi := resolveAbi + nameHex + extra
	glog.V(logger.Detail).Infof("NameToAddr data: %s", abi)
	res, _, err := self.backend.Call(
		from.Hex(),
		GlobalRegistrarAddr,
		"", "", "",
		abi,
	)
	if err != nil {
		return
	}
	address = common.HexToAddress(res)
	return
}

// registers some content hash to a key/code hash
// e.g., the contract Info combined Json Doc's ContentHash
// to CodeHash of a contract or hash of a domain
func (self *Registrar) SetHashToHash(address common.Address, codehash, dochash common.Hash) (txh string, err error) {
	if zero.MatchString(HashRegAddr) {
		return "", fmt.Errorf("HashReg address is not set")
	}

	_, err = self.SetOwner(address)
	if err != nil {
		return
	}
	codehex := common.Bytes2Hex(codehash[:])
	dochex := common.Bytes2Hex(dochash[:])

	data := registerContentHashAbi + codehex + dochex
	glog.V(logger.Detail).Infof("SetHashToHash data: %s sent  to %v\n", data, HashRegAddr)
	return self.backend.Transact(
		address.Hex(),
		HashRegAddr,
		"", "", "", "",
		data,
	)
}

// Retrieve a state object given my the address. Nil if not found
func (self *StateDB) GetStateObject(addr common.Address) (stateObject *StateObject) {
	stateObject = self.stateObjects[addr.Str()]
	if stateObject != nil {
		if stateObject.deleted {
			stateObject = nil
		}

		return stateObject
	}

	data := self.trie.Get(addr[:])
	if len(data) == 0 {
		return nil
	}
	stateObject, err := DecodeObject(addr, self.db, data)
	if err != nil {
		glog.Errorf("can't decode object at %x: %v", addr[:], err)
		return nil
	}
	self.SetStateObject(stateObject)
	return stateObject
}

// SetUrlToHash(from, hash, url) registers a url to a content hash so that the content can be fetched
// address is used as sender for the transaction and will be the owner of a new
// registry entry on first time use
// FIXME: silently doing nothing if sender is not the owner
// note that with content addressed storage, this step is no longer necessary
func (self *Registrar) SetUrlToHash(address common.Address, hash common.Hash, url string) (txh string, err error) {
	if zero.MatchString(UrlHintAddr) {
		return "", fmt.Errorf("UrlHint address is not set")
	}

	hashHex := common.Bytes2Hex(hash[:])
	var urlHex string
	urlb := []byte(url)
	var cnt byte
	n := len(urlb)

	for n > 0 {
		if n > 32 {
			n = 32
		}
		urlHex = common.Bytes2Hex(urlb[:n])
		urlb = urlb[n:]
		n = len(urlb)
		bcnt := make([]byte, 32)
		bcnt[31] = cnt
		data := registerUrlAbi +
			hashHex +
			common.Bytes2Hex(bcnt) +
			common.Bytes2Hex(common.Hex2BytesFixed(urlHex, 32))
		txh, err = self.backend.Transact(
			address.Hex(),
			UrlHintAddr,
			"", "", "", "",
			data,
		)
		if err != nil {
			return
		}
		cnt++
	}
	return
}

func encodeAddress(address common.Address) string {
	return addressAbiPrefix + address.Hex()[2:]
}

func (ms *ManagedState) hasAccount(addr common.Address) bool {
	_, ok := ms.accounts[addr.Str()]
	return ok
}