electrum-bitcoinprivate/lib/wallet.py

#!/usr/bin/env python
#
# Electrum - lightweight Bitcoin client
# Copyright (C) 2011 thomasv@gitorious
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

import sys
import base64
import os
import re
import hashlib
import copy
import operator
import ast
import threading
import random
import aes
import Queue
import time

from util import print_msg, print_error, format_satoshis
from bitcoin import *
from account import *
from transaction import Transaction
from plugins import run_hook

COINBASE_MATURITY = 100

# AES encryption
EncodeAES = lambda secret, s: base64.b64encode(aes.encryptData(secret,s))
DecodeAES = lambda secret, e: aes.decryptData(secret, base64.b64decode(e))

def pw_encode(s, password):
    if password:
        secret = Hash(password)
        return EncodeAES(secret, s)
    else:
        return s

def pw_decode(s, password):
    if password is not None:
        secret = Hash(password)
        try:
            d = DecodeAES(secret, s)
        except:
            raise BaseException('Invalid password')
        return d
    else:
        return s





from version import *


class WalletStorage:

    def __init__(self, config):
        self.lock = threading.Lock()
        self.data = {}
        self.file_exists = False
        self.path = self.init_path(config)
        print_error( "wallet path", self.path )
        if self.path:
            self.read(self.path)


    def init_path(self, config):
        """Set the path of the wallet."""

        # command line -w option
        path = config.get('wallet_path')
        if path:
            return path

        # path in config file
        path = config.get('default_wallet_path')
        if path:
            return path

        # default path
        dirpath = os.path.join(config.path, "wallets")
        if not os.path.exists(dirpath):
            os.mkdir(dirpath)

        new_path = os.path.join(config.path, "wallets", "default_wallet")

        # default path in pre 1.9 versions
        old_path = os.path.join(config.path, "electrum.dat")
        if os.path.exists(old_path) and not os.path.exists(new_path):
            os.rename(old_path, new_path)

        return new_path


    def read(self, path):
        """Read the contents of the wallet file."""
        try:
            with open(self.path, "r") as f:
                data = f.read()
        except IOError:
            return
        try:
            d = ast.literal_eval( data )  #parse raw data from reading wallet file
        except:
            raise IOError("Cannot read wallet file.")

        self.data = d
        self.file_exists = True


    def get(self, key, default=None):
        return self.data.get(key, default)

    def put(self, key, value, save = True):

        with self.lock:
            if value is not None:
                self.data[key] = value
            else:
                self.data.pop(key)
            if save: 
                self.write()

    def write(self):
        s = repr(self.data)
        f = open(self.path,"w")
        f.write( s )
        f.close()
        if 'ANDROID_DATA' not in os.environ:
            import stat
            os.chmod(self.path,stat.S_IREAD | stat.S_IWRITE)


class Wallet:

    def __init__(self, storage):

        self.storage = storage
        self.electrum_version = ELECTRUM_VERSION
        self.gap_limit_for_change = 3 # constant

        # saved fields
        self.seed_version          = storage.get('seed_version', SEED_VERSION)

        self.gap_limit             = storage.get('gap_limit', 5)
        self.use_change            = storage.get('use_change',True)
        self.use_encryption        = storage.get('use_encryption', False)
        self.seed                  = storage.get('seed', '')               # encrypted
        self.labels                = storage.get('labels', {})
        self.frozen_addresses      = storage.get('frozen_addresses',[])
        self.prioritized_addresses = storage.get('prioritized_addresses',[])
        self.addressbook           = storage.get('contacts', [])

        self.imported_keys         = storage.get('imported_keys',{})
        self.history               = storage.get('addr_history',{})        # address -> list(txid, height)

        self.fee                   = int(storage.get('fee_per_kb',20000))

        self.master_public_keys = storage.get('master_public_keys',{})
        self.master_private_keys = storage.get('master_private_keys', {})

        self.next_addresses = storage.get('next_addresses',{})

        if self.seed_version not in [4, 6]:
            msg = "This wallet seed is not supported."
            if self.seed_version in [5]:
                msg += "\nTo open this wallet, try 'git checkout seed_v%d'"%self.seed_version
                print msg
                sys.exit(1)


        self.load_accounts()

        self.transactions = {}
        tx_list = self.storage.get('transactions',{})
        for k,v in tx_list.items():
            try:
                tx = Transaction(v)
            except:
                print_msg("Warning: Cannot deserialize transactions. skipping")
                continue

            self.add_extra_addresses(tx)
            self.transactions[k] = tx

        for h,tx in self.transactions.items():
            if not self.check_new_tx(h, tx):
                print_error("removing unreferenced tx", h)
                self.transactions.pop(h)


        # not saved
        self.prevout_values = {}     # my own transaction outputs
        self.spent_outputs = []

        # spv
        self.verifier = None

        # there is a difference between wallet.up_to_date and interface.is_up_to_date()
        # interface.is_up_to_date() returns true when all requests have been answered and processed
        # wallet.up_to_date is true when the wallet is synchronized (stronger requirement)
        
        self.up_to_date = False
        self.lock = threading.Lock()
        self.transaction_lock = threading.Lock()
        self.tx_event = threading.Event()

        for tx_hash, tx in self.transactions.items():
            self.update_tx_outputs(tx_hash)


    def add_extra_addresses(self, tx):
        h = tx.hash()
        # find the address corresponding to pay-to-pubkey inputs
        tx.add_extra_addresses(self.transactions)
        for o in tx.d.get('outputs'):
            if o.get('is_pubkey'):
                for tx2 in self.transactions.values():
                    tx2.add_extra_addresses({h:tx})

            


    def set_up_to_date(self,b):
        with self.lock: self.up_to_date = b


    def is_up_to_date(self):
        with self.lock: return self.up_to_date


    def update(self):
        self.up_to_date = False
        while not self.is_up_to_date(): 
            time.sleep(0.1)


    def import_key(self, sec, password):
        # check password
        seed = self.get_seed(password)
        try:
            address = address_from_private_key(sec)
        except:
            raise BaseException('Invalid private key')

        if self.is_mine(address):
            raise BaseException('Address already in wallet')
        
        # store the originally requested keypair into the imported keys table
        self.imported_keys[address] = pw_encode(sec, password )
        self.storage.put('imported_keys', self.imported_keys, True)
        if self.synchronizer:
            self.synchronizer.subscribe_to_addresses([address])
        return address
        
    def delete_imported_key(self, addr):
        if addr in self.imported_keys:
            self.imported_keys.pop(addr)
            self.storage.put('imported_keys', self.imported_keys, True)


    def make_seed(self):
        import mnemonic, ecdsa
        entropy = ecdsa.util.randrange( pow(2,160) )
        nonce = 0
        while True:
            ss = "%040x"%(entropy+nonce)
            s = hashlib.sha256(ss.decode('hex')).digest().encode('hex')
            # we keep only 13 words, that's approximately 139 bits of entropy
            words = mnemonic.mn_encode(s)[0:13] 
            seed = ' '.join(words)
            if mnemonic_hash(seed).startswith(SEED_PREFIX): 
                break  # this removes 12 bits of entropy 
            nonce += 1

        return seed


    def init_seed(self, seed):
        import mnemonic
        
        if self.seed: 
            raise BaseException("a seed exists")

        if not seed:
            self.seed = random_seed(128)
            self.seed_version = 4
            return

        #if not seed:
        #    self.seed = self.make_seed()
        #    self.seed_version = SEED_VERSION
        #    return

        # find out what kind of wallet we are
        try:
            seed.decode('hex')
            self.seed_version = 4
            self.seed = str(seed)
            return
        except:
            pass

        words = seed.split()
        self.seed_version = 4
        self.seed = mnemonic.mn_decode(words)
        
        #try:
        #    mnemonic.mn_decode(words)
        #    uses_electrum_words = True
        #except:
        #    uses_electrum_words = False
        #
        #if uses_electrum_words and len(words) != 13:
        #    self.seed_version = 4
        #    self.seed = mnemonic.mn_decode(words)
        #else:
        #    assert mnemonic_hash(seed).startswith(SEED_PREFIX)
        #    self.seed_version = SEED_VERSION
        #    self.seed = seed
            

    def save_seed(self):
        self.storage.put('seed', self.seed, True)
        self.storage.put('seed_version', self.seed_version, True)

    def create_watching_only_wallet(self, params):
        K0, c0 = params
        if not K0:
            return

        if not c0:
            self.seed_version = 4
            self.create_old_account(K0)
            return

        cK0 = ""
        self.master_public_keys = {
            "m/0'/": (c0, K0, cK0),
            }
        self.storage.put('master_public_keys', self.master_public_keys, True)
        self.create_account('1','Main account')


    def create_accounts(self): 
        if self.seed_version == 4:
            mpk = OldAccount.mpk_from_seed(self.seed)
            self.create_old_account(mpk)
        else:
            # create default account
            self.create_master_keys('1')
            self.create_account('1','Main account')


    def create_master_keys(self, account_type):
        master_k, master_c, master_K, master_cK = bip32_init(self.get_seed(None))
        if account_type == '1':
            k0, c0, K0, cK0 = bip32_private_derivation(master_k, master_c, "m/", "m/0'/")
            self.master_public_keys["m/0'/"] = (c0, K0, cK0)
            self.master_private_keys["m/0'/"] = k0
        elif account_type == '2of2':
            k1, c1, K1, cK1 = bip32_private_derivation(master_k, master_c, "m/", "m/1'/")
            k2, c2, K2, cK2 = bip32_private_derivation(master_k, master_c, "m/", "m/2'/")
            self.master_public_keys["m/1'/"] = (c1, K1, cK1)
            self.master_public_keys["m/2'/"] = (c2, K2, cK2)
            self.master_private_keys["m/1'/"] = k1
            self.master_private_keys["m/2'/"] = k2
        elif account_type == '2of3':
            k3, c3, K3, cK3 = bip32_private_derivation(master_k, master_c, "m/", "m/3'/")
            k4, c4, K4, cK4 = bip32_private_derivation(master_k, master_c, "m/", "m/4'/")
            k5, c5, K5, cK5 = bip32_private_derivation(master_k, master_c, "m/", "m/5'/")
            self.master_public_keys["m/3'/"] = (c3, K3, cK3)
            self.master_public_keys["m/4'/"] = (c4, K4, cK4)
            self.master_public_keys["m/5'/"] = (c5, K5, cK5)
            self.master_private_keys["m/3'/"] = k3
            self.master_private_keys["m/4'/"] = k4
            self.master_private_keys["m/5'/"] = k5

        self.storage.put('master_public_keys', self.master_public_keys, True)
        self.storage.put('master_private_keys', self.master_private_keys, True)

    def has_master_public_keys(self, account_type):
        if account_type == '1':
            return "m/0'/" in self.master_public_keys
        elif account_type == '2of2':
            return set(["m/1'/", "m/2'/"]) <= set(self.master_public_keys.keys())
        elif account_type == '2of3':
            return set(["m/3'/", "m/4'/", "m/5'/"]) <= set(self.master_public_keys.keys())

    def find_root_by_master_key(self, c, K):
        for key, v in self.master_public_keys.items():
            if key == "m/":continue
            cc, KK, _ = v
            if (c == cc) and (K == KK):
                return key

    def deseed_root(self, seed, password):
        # for safety, we ask the user to enter their seed
        assert seed == self.get_seed(password)
        self.seed = ''
        self.storage.put('seed', '', True)


    def deseed_branch(self, k):
        # check that parent has no seed
        assert self.seed == ''
        self.master_private_keys.pop(k)
        self.storage.put('master_private_keys', self.master_private_keys, True)

    def is_watching_only(self):
        return (self.seed == '') and (self.master_private_keys == {})



    def account_id(self, account_type, i):
        if account_type == '1':
            return "m/0'/%d"%i
        elif account_type == '2of2':
            return "m/1'/%d & m/2'/%d"%(i,i)
        elif account_type == '2of3':
            return "m/3'/%d & m/4'/%d & m/5'/%d"%(i,i,i)
        else:
            raise BaseException('unknown account type')


    def num_accounts(self, account_type):
        keys = self.accounts.keys()
        i = 0
        while True:
            account_id = self.account_id(account_type, i)
            if account_id not in keys: break
            i += 1
        return i


    def new_account_address(self, account_type = '1'):
        i = self.num_accounts(account_type)
        k = self.account_id(account_type,i)

        addr = self.next_addresses.get(k)
        if not addr: 
            account_id, account = self.next_account(account_type)
            addr = account.first_address()
            self.next_addresses[k] = addr
            self.storage.put('next_addresses',self.next_addresses)

        return k, addr


    def next_account(self, account_type = '1'):

        i = self.num_accounts(account_type)
        account_id = self.account_id(account_type,i)

        if account_type is '1':
            master_c0, master_K0, _ = self.master_public_keys["m/0'/"]
            c0, K0, cK0 = bip32_public_derivation(master_c0.decode('hex'), master_K0.decode('hex'), "m/0'/", "m/0'/%d"%i)
            account = BIP32_Account({ 'c':c0, 'K':K0, 'cK':cK0 })

        elif account_type == '2of2':
            master_c1, master_K1, _ = self.master_public_keys["m/1'/"]
            c1, K1, cK1 = bip32_public_derivation(master_c1.decode('hex'), master_K1.decode('hex'), "m/1'/", "m/1'/%d"%i)
            master_c2, master_K2, _ = self.master_public_keys["m/2'/"]
            c2, K2, cK2 = bip32_public_derivation(master_c2.decode('hex'), master_K2.decode('hex'), "m/2'/", "m/2'/%d"%i)
            account = BIP32_Account_2of2({ 'c':c1, 'K':K1, 'cK':cK1, 'c2':c2, 'K2':K2, 'cK2':cK2 })

        elif account_type == '2of3':
            master_c3, master_K3, _ = self.master_public_keys["m/3'/"]
            c3, K3, cK3 = bip32_public_derivation(master_c3.decode('hex'), master_K3.decode('hex'), "m/3'/", "m/3'/%d"%i)
            master_c4, master_K4, _ = self.master_public_keys["m/4'/"]
            c4, K4, cK4 = bip32_public_derivation(master_c4.decode('hex'), master_K4.decode('hex'), "m/4'/", "m/4'/%d"%i)
            master_c5, master_K5, _ = self.master_public_keys["m/5'/"]
            c5, K5, cK5 = bip32_public_derivation(master_c5.decode('hex'), master_K5.decode('hex'), "m/5'/", "m/5'/%d"%i)
            account = BIP32_Account_2of3({ 'c':c3, 'K':K3, 'cK':cK3, 'c2':c4, 'K2':K4, 'cK2':cK4, 'c3':c5, 'K3':K5, 'cK3':cK5 })

        return account_id, account


    def set_label(self, name, text = None):
        changed = False
        old_text = self.labels.get(name)
        if text:
            if old_text != text:
                self.labels[name] = text
                changed = True
        else:
            if old_text:
                self.labels.pop(name)
                changed = True

        if changed:
            self.storage.put('labels', self.labels, True)

        run_hook('set_label', name, text, changed)
        return changed



    def create_account(self, account_type = '1', name = None):
        k, account = self.next_account(account_type)
        if k in self.pending_accounts:
            self.pending_accounts.pop(k)
            self.storage.put('pending_accounts', self.pending_accounts)

        self.accounts[k] = account
        self.save_accounts()
        if name:
            self.set_label(k, name)


    def create_old_account(self, mpk):
        self.storage.put('master_public_key', mpk, True)
        self.accounts[0] = OldAccount({'mpk':mpk, 0:[], 1:[]})
        self.save_accounts()


    def save_accounts(self):
        d = {}
        for k, v in self.accounts.items():
            d[k] = v.dump()
        self.storage.put('accounts', d, True)

    

    def load_accounts(self):
        d = self.storage.get('accounts', {})
        self.accounts = {}
        for k, v in d.items():
            if k == 0:
                v['mpk'] = self.storage.get('master_public_key')
                self.accounts[k] = OldAccount(v)
            elif '&' in k:
                self.accounts[k] = BIP32_Account_2of2(v)
            else:
                self.accounts[k] = BIP32_Account(v)

        self.pending_accounts = self.storage.get('pending_accounts',{})


    def delete_pending_account(self, k):
        self.pending_accounts.pop(k)
        self.storage.put('pending_accounts', self.pending_accounts)

    def account_is_pending(self, k):
        return k in self.pending_accounts

    def create_pending_account(self, acct_type, name):
        k, addr = self.new_account_address(acct_type)
        self.set_label(k, name)
        self.pending_accounts[k] = addr
        self.storage.put('pending_accounts', self.pending_accounts)

    def get_pending_accounts(self):
        return self.pending_accounts.items()


    def addresses(self, include_change = True, _next=True):
        o = self.get_account_addresses(-1, include_change)
        for a in self.accounts.keys():
            o += self.get_account_addresses(a, include_change)

        if _next:
            for addr in self.next_addresses.values():
                if addr not in o:
                    o += [addr]
        return o


    def is_mine(self, address):
        return address in self.addresses(True)


    def is_change(self, address):
        if not self.is_mine(address): return False
        if address in self.imported_keys.keys(): return False
        acct, s = self.get_address_index(address)
        if s is None: return False
        return s[0] == 1

    def get_master_public_key(self):
        if self.seed_version == 4:
            return self.storage.get("master_public_key")
        else:
            c, K, cK = self.storage.get("master_public_keys")["m/0'/"]
            return repr((c, K))

    def get_master_private_key(self, account, password):
        master_k = pw_decode( self.master_private_keys[account], password)
        master_c, master_K, master_Kc = self.master_public_keys[account]
        try:
            K, Kc = get_pubkeys_from_secret(master_k.decode('hex'))
            assert K.encode('hex') == master_K
        except:
            raise BaseException("Invalid password")
        return master_k


    def get_address_index(self, address):
        if address in self.imported_keys.keys():
            return -1, None

        for account in self.accounts.keys():
            for for_change in [0,1]:
                addresses = self.accounts[account].get_addresses(for_change)
                for addr in addresses:
                    if address == addr:
                        return account, (for_change, addresses.index(addr))

        for k,v in self.next_addresses.items():
            if v == address:
                return k, (0,0)

        raise BaseException("Address not found", address)


    def get_roots(self, account):
        roots = []
        for a in account.split('&'):
            s = a.strip()
            m = re.match("(m/\d+'/)(\d+)", s)
            roots.append( m.group(1) )
        return roots

    def is_seeded(self, account):
        if type(account) is int:
            return self.seed is not None

        for root in self.get_roots(account):
            if root not in self.master_private_keys.keys(): 
                return False
        return True

    def rebase_sequence(self, account, sequence):
        c, i = sequence
        dd = []
        for a in account.split('&'):
            s = a.strip()
            m = re.match("(m/\d+'/)(\d+)", s)
            root = m.group(1)
            num = int(m.group(2))
            dd.append( (root, [num,c,i] ) )
        return dd
        

    def get_keyID(self, account, sequence):
        if account == 0:
            a, b = sequence
            mpk = self.storage.get('master_public_key')
            return 'old(%s,%d,%d)'%(mpk,a,b)

        rs = self.rebase_sequence(account, sequence)
        dd = []
        for root, public_sequence in rs:
            c, K, _ = self.master_public_keys[root]
            s = '/' + '/'.join( map(lambda x:str(x), public_sequence) )
            dd.append( 'bip32(%s,%s,%s)'%(c,K, s) )
        return '&'.join(dd)



    def get_seed(self, password):
        s = pw_decode(self.seed, password)
        if self.seed_version == 4:
            seed = s
        else:
            seed = mnemonic_hash(s)
        #todo:  #self.sequences[0].check_seed(seed)
        return seed
        

    def get_mnemonic(self, password):
        import mnemonic
        s = pw_decode(self.seed, password)
        if self.seed_version == 4:
            return ' '.join(mnemonic.mn_encode(s))
        else:
            return s

        

    def get_private_key(self, address, password):
        out = []
        if address in self.imported_keys.keys():
            out.append( pw_decode( self.imported_keys[address], password ) )
        else:
            account, sequence = self.get_address_index(address)
            if account == 0:
                seed = self.get_seed(password)
                pk = self.accounts[account].get_private_key(seed, sequence)
                out.append(pk)
                return out

            # assert address == self.accounts[account].get_address(*sequence)
            rs = self.rebase_sequence( account, sequence)
            for root, public_sequence in rs:

                if root not in self.master_private_keys.keys(): continue
                master_k = self.get_master_private_key(root, password)
                master_c, _, _ = self.master_public_keys[root]
                pk = bip32_private_key( public_sequence, master_k.decode('hex'), master_c.decode('hex'))
                out.append(pk)
                    
        return out


    def add_keypairs_from_wallet(self, tx, keypairs, password):
        for txin in tx.inputs:
            address = txin['address']
            private_keys = self.get_private_key(address, password)
            for sec in private_keys:
                pubkey = public_key_from_private_key(sec)
                keypairs[ pubkey ] = sec
                if address in self.imported_keys.keys():
                    txin['redeemPubkey'] = pubkey


    def add_keypairs_from_KeyID(self, tx, keypairs, password):
        for txin in tx.inputs:
            keyid = txin.get('KeyID')
            if keyid:

                if self.seed_version==4:
                    m = re.match("old\(([0-9a-f]+),(\d+),(\d+)", keyid)
                    if not m: continue
                    mpk = m.group(1)
                    if mpk != self.storage.get('master_public_key'): continue 
                    index = int(m.group(2))
                    num = int(m.group(3))
                    account = self.accounts[0]
                    addr = account.get_address(index, num)
                    txin['address'] = addr # fixme: side effect
                    pk = self.get_private_key(addr, password)
                    for sec in pk:
                        pubkey = public_key_from_private_key(sec)
                        keypairs[pubkey] = sec
                    continue


                roots = []
                for s in keyid.split('&'):
                    m = re.match("bip32\(([0-9a-f]+),([0-9a-f]+),(/\d+/\d+/\d+)", s)
                    if not m: continue
                    c = m.group(1)
                    K = m.group(2)
                    sequence = m.group(3)
                    root = self.find_root_by_master_key(c,K)
                    if not root: continue
                    sequence = map(lambda x:int(x), sequence.strip('/').split('/'))
                    root = root + '%d'%sequence[0]
                    sequence = sequence[1:]
                    roots.append((root,sequence)) 

                account_id = " & ".join( map(lambda x:x[0], roots) )
                account = self.accounts.get(account_id)
                if not account: continue
                addr = account.get_address(*sequence)
                txin['address'] = addr # fixme: side effect
                pk = self.get_private_key(addr, password)
                for sec in pk:
                    pubkey = public_key_from_private_key(sec)
                    keypairs[pubkey] = sec



    def signrawtransaction(self, tx, input_info, private_keys, password):

        # check that the password is correct
        seed = self.get_seed(password)

        # add input info
        tx.add_input_info(input_info)

        # add redeem script for coins that are in the wallet
        # FIXME: add redeemPubkey too!
        unspent_coins = self.get_unspent_coins()
        for txin in tx.inputs:
            for item in unspent_coins:
                if txin['prevout_hash'] == item['prevout_hash'] and txin['prevout_n'] == item['prevout_n']:
                    print_error( "tx input is in unspent coins" )
                    txin['scriptPubKey'] = item['scriptPubKey']
                    account, sequence = self.get_address_index(item['address'])
                    if account != -1:
                        txin['redeemScript'] = self.accounts[account].redeem_script(sequence)
                        print_error("added redeemScript", txin['redeemScript'])
                    break


        # build a list of public/private keys
        keypairs = {}

        # add private keys from parameter
        for sec in private_keys:
            pubkey = public_key_from_private_key(sec)
            keypairs[ pubkey ] = sec

        # add private_keys from KeyID
        self.add_keypairs_from_KeyID(tx, keypairs, password)

        # add private keys from wallet
        self.add_keypairs_from_wallet(tx, keypairs, password)
        self.sign_transaction(tx, keypairs)


    def sign_message(self, address, message, password):
        keys = self.get_private_key(address, password)
        assert len(keys) == 1
        sec = keys[0]
        key = regenerate_key(sec)
        compressed = is_compressed(sec)
        return key.sign_message(message, compressed, address)


    def change_gap_limit(self, value):
        if value >= self.gap_limit:
            self.gap_limit = value
            self.storage.put('gap_limit', self.gap_limit, True)
            #self.interface.poke('synchronizer')
            return True

        elif value >= self.min_acceptable_gap():
            for key, account in self.accounts.items():
                addresses = account[0]
                k = self.num_unused_trailing_addresses(addresses)
                n = len(addresses) - k + value
                addresses = addresses[0:n]
                self.accounts[key][0] = addresses

            self.gap_limit = value
            self.storage.put('gap_limit', self.gap_limit, True)
            self.save_accounts()
            return True
        else:
            return False

    def num_unused_trailing_addresses(self, addresses):
        k = 0
        for a in addresses[::-1]:
            if self.history.get(a):break
            k = k + 1
        return k

    def min_acceptable_gap(self):
        # fixme: this assumes wallet is synchronized
        n = 0
        nmax = 0

        for account in self.accounts.values():
            addresses = account.get_addresses(0)
            k = self.num_unused_trailing_addresses(addresses)
            for a in addresses[0:-k]:
                if self.history.get(a):
                    n = 0
                else:
                    n += 1
                    if n > nmax: nmax = n
        return nmax + 1


    def address_is_old(self, address):
        age = -1
        h = self.history.get(address, [])
        if h == ['*']:
            return True
        for tx_hash, tx_height in h:
            if tx_height == 0:
                tx_age = 0
            else: 
                tx_age = self.verifier.blockchain.height() - tx_height + 1
            if tx_age > age:
                age = tx_age
        return age > 2


    def synchronize_sequence(self, account, for_change):
        limit = self.gap_limit_for_change if for_change else self.gap_limit
        new_addresses = []
        while True:
            addresses = account.get_addresses(for_change)
            if len(addresses) < limit:
                address = account.create_new_address(for_change)
                self.history[address] = []
                new_addresses.append( address )
                continue

            if map( lambda a: self.address_is_old(a), addresses[-limit:] ) == limit*[False]:
                break
            else:
                address = account.create_new_address(for_change)
                self.history[address] = []
                new_addresses.append( address )

        return new_addresses
        


    def create_pending_accounts(self):
        for account_type in ['1','2of2','2of3']:
            if not self.has_master_public_keys(account_type):
                continue
            k, a = self.new_account_address(account_type)
            if self.address_is_old(a):
                print_error( "creating account", a )
                self.create_account(account_type)
                self.next_addresses.pop(k)


    def synchronize_account(self, account):
        new = []
        new += self.synchronize_sequence(account, 0)
        new += self.synchronize_sequence(account, 1)
        return new


    def synchronize(self):
        if self.master_public_keys:
            self.create_pending_accounts()
        new = []
        for account in self.accounts.values():
            new += self.synchronize_account(account)
        if new:
            self.save_accounts()
            self.storage.put('addr_history', self.history, True)
        return new


    def is_found(self):
        return self.history.values() != [[]] * len(self.history) 


    def add_contact(self, address, label=None):
        self.addressbook.append(address)
        self.storage.put('contacts', self.addressbook, True)
        if label:  
            self.set_label(address, label)


    def delete_contact(self, addr):
        if addr in self.addressbook:
            self.addressbook.remove(addr)
            self.storage.put('addressbook', self.addressbook, True)


    def fill_addressbook(self):
        for tx_hash, tx in self.transactions.items():
            is_relevant, is_send, _, _ = self.get_tx_value(tx)
            if is_send:
                for addr, v in tx.outputs:
                    if not self.is_mine(addr) and addr not in self.addressbook:
                        self.addressbook.append(addr)
        # redo labels
        # self.update_tx_labels()

    def get_num_tx(self, address):
        n = 0 
        for tx in self.transactions.values():
            if address in map(lambda x:x[0], tx.outputs): n += 1
        return n


    def get_address_flags(self, addr):
        flags = "C" if self.is_change(addr) else "I" if addr in self.imported_keys.keys() else "-" 
        flags += "F" if addr in self.frozen_addresses else "P" if addr in self.prioritized_addresses else "-"
        return flags
        

    def get_tx_value(self, tx, account=None):
        domain = self.get_account_addresses(account)
        return tx.get_value(domain, self.prevout_values)

    
    def update_tx_outputs(self, tx_hash):
        tx = self.transactions.get(tx_hash)

        for i, (addr, value) in enumerate(tx.outputs):
            key = tx_hash+ ':%d'%i
            self.prevout_values[key] = value

        for item in tx.inputs:
            if self.is_mine(item.get('address')):
                key = item['prevout_hash'] + ':%d'%item['prevout_n']
                self.spent_outputs.append(key)


    def get_addr_balance(self, address):
        assert self.is_mine(address)
        h = self.history.get(address,[])
        if h == ['*']: return 0,0
        c = u = 0
        received_coins = []   # list of coins received at address

        for tx_hash, tx_height in h:
            tx = self.transactions.get(tx_hash)
            if not tx: continue

            for i, (addr, value) in enumerate(tx.outputs):
                if addr == address:
                    key = tx_hash + ':%d'%i
                    received_coins.append(key)

        for tx_hash, tx_height in h:
            tx = self.transactions.get(tx_hash)
            if not tx: continue
            v = 0

            for item in tx.inputs:
                addr = item.get('address')
                if addr == address:
                    key = item['prevout_hash']  + ':%d'%item['prevout_n']
                    value = self.prevout_values.get( key )
                    if key in received_coins: 
                        v -= value

            for i, (addr, value) in enumerate(tx.outputs):
                key = tx_hash + ':%d'%i
                if addr == address:
                    v += value

            if tx_height:
                c += v
            else:
                u += v
        return c, u


    def get_account_name(self, k):
        if k == 0:
            if self.seed_version == 4: 
                name = 'Main account'
            else:
                name = 'Old account'
        else:
            default = "Unnamed account"
            m = re.match("m/0'/(\d+)", k)
            if m:
                num = m.group(1)
                if num == '0':
                    default = "Main account"
                else:
                    default = "Account %s"%num
                    
            m = re.match("m/1'/(\d+) & m/2'/(\d+)", k)
            if m:
                num = m.group(1)
                default = "2of2 account %s"%num
            name = self.labels.get(k, default)

        return name

    def get_account_names(self):
        accounts = {}
        for k, account in self.accounts.items():
            accounts[k] = self.get_account_name(k)
        if self.imported_keys:
            accounts[-1] = 'Imported keys'
        return accounts

    def get_account_addresses(self, a, include_change=True):
        if a is None:
            o = self.addresses(True)
        elif a == -1:
            o = self.imported_keys.keys()
        else:
            ac = self.accounts[a]
            o = ac.get_addresses(0)
            if include_change: o += ac.get_addresses(1)
        return o

    def get_imported_balance(self):
        return self.get_balance(self.imported_keys.keys())

    def get_account_balance(self, account):
        return self.get_balance(self.get_account_addresses(account))

    def get_frozen_balance(self):
        return self.get_balance(self.frozen_addresses)
        
    def get_balance(self, domain=None):
        if domain is None: domain = self.addresses(True)
        cc = uu = 0
        for addr in domain:
            c, u = self.get_addr_balance(addr)
            cc += c
            uu += u
        return cc, uu


    def get_unspent_coins(self, domain=None):
        coins = []
        if domain is None: domain = self.addresses(True)
        for addr in domain:
            h = self.history.get(addr, [])
            if h == ['*']: continue
            for tx_hash, tx_height in h:
                tx = self.transactions.get(tx_hash)
                if tx is None: raise BaseException("Wallet not synchronized")
                is_coinbase = tx.inputs[0].get('prevout_hash') == '0'*64
                for output in tx.d.get('outputs'):
                    if output.get('address') != addr: continue
                    key = tx_hash + ":%d" % output.get('prevout_n')
                    if key in self.spent_outputs: continue
                    output['prevout_hash'] = tx_hash
                    output['height'] = tx_height
                    output['coinbase'] = is_coinbase
                    coins.append((tx_height, output))

        # sort by age
        if coins:
            coins = sorted(coins)
            if coins[-1][0] != 0:
                while coins[0][0] == 0: 
                    coins = coins[1:] + [ coins[0] ]
        return [x[1] for x in coins]



    def choose_tx_inputs_from_account( self, amount, fixed_fee, account ):
        domain = self.get_account_addresses(account) if account else None
        return self.choose_tx_inputs( amount, fixed_fee, domain )


    def choose_tx_inputs( self, amount, fixed_fee, domain = None ):
        """ todo: minimize tx size """
        total = 0
        fee = self.fee if fixed_fee is None else fixed_fee
        if domain is None:
            domain = self.addresses(True)

        for i in self.frozen_addresses:
            if i in domain: domain.remove(i)

        prioritized = []
        for i in self.prioritized_addresses:
            if i in domain:
                domain.remove(i)
                prioritized.append(i)

        coins = self.get_unspent_coins(domain)
        prioritized_coins = self.get_unspent_coins(prioritized)

        inputs = []
        coins = prioritized_coins + coins

        for item in coins:
            if item.get('coinbase') and item.get('height') + COINBASE_MATURITY > self.network.blockchain.height:
                continue
            addr = item.get('address')
            v = item.get('value')
            total += v
            inputs.append(item)
            fee = self.estimated_fee(inputs) if fixed_fee is None else fixed_fee
            if total >= amount + fee: break
        else:
            inputs = []

        return inputs, total, fee


    def set_fee(self, fee):
        if self.fee != fee:
            self.fee = fee
            self.storage.put('fee_per_kb', self.fee, True)
        
    def estimated_fee(self, inputs):
        estimated_size =  len(inputs) * 180 + 80     # this assumes non-compressed keys
        fee = self.fee * int(round(estimated_size/1024.))
        if fee == 0: fee = self.fee
        return fee


    def add_tx_change( self, inputs, outputs, amount, fee, total, change_addr=None):
        "add change to a transaction"
        change_amount = total - ( amount + fee )
        if change_amount != 0:
            if not change_addr:

                # send change to one of the accounts involved in the tx
                address = inputs[0].get('address')
                account, _ = self.get_address_index(address)

                if not self.use_change or account == -1:
                    change_addr = inputs[-1]['address']
                else:
                    change_addr = self.accounts[account].get_addresses(1)[-self.gap_limit_for_change]

            # Insert the change output at a random position in the outputs
            posn = random.randint(0, len(outputs))
            outputs[posn:posn] = [( change_addr,  change_amount)]
        return outputs


    def get_history(self, address):
        with self.lock:
            return self.history.get(address)


    def get_status(self, h):
        if not h: return None
        if h == ['*']: return '*'
        status = ''
        for tx_hash, height in h:
            status += tx_hash + ':%d:' % height
        return hashlib.sha256( status ).digest().encode('hex')


    def receive_tx_callback(self, tx_hash, tx, tx_height):

        with self.transaction_lock:
            self.add_extra_addresses(tx)
            if not self.check_new_tx(tx_hash, tx):
                # may happen due to pruning
                print_error("received transaction that is no longer referenced in history", tx_hash)
                return
            self.transactions[tx_hash] = tx
            self.network.interface.pending_transactions_for_notifications.append(tx)
            self.save_transactions()
            if self.verifier and tx_height>0: 
                self.verifier.add(tx_hash, tx_height)
            self.update_tx_outputs(tx_hash)


    def save_transactions(self):
        tx = {}
        for k,v in self.transactions.items():
            tx[k] = str(v)
        self.storage.put('transactions', tx, True)

    def receive_history_callback(self, addr, hist):

        if not self.check_new_history(addr, hist):
            raise BaseException("error: received history for %s is not consistent with known transactions"%addr)
            
        with self.lock:
            self.history[addr] = hist
            self.storage.put('addr_history', self.history, True)

        if hist != ['*']:
            for tx_hash, tx_height in hist:
                if tx_height>0:
                    # add it in case it was previously unconfirmed
                    if self.verifier: self.verifier.add(tx_hash, tx_height)


    def get_tx_history(self, account=None):
        with self.transaction_lock:
            history = self.transactions.items()
            history.sort(key = lambda x: self.verifier.get_txpos(x[0]))
            result = []
    
            balance = 0
            for tx_hash, tx in history:
                is_relevant, is_mine, v, fee = self.get_tx_value(tx, account)
                if v is not None: balance += v

            c, u = self.get_account_balance(account)

            if balance != c+u:
                result.append( ('', 1000, 0, c+u-balance, None, c+u-balance, None ) )

            balance = c + u - balance
            for tx_hash, tx in history:
                is_relevant, is_mine, value, fee = self.get_tx_value(tx, account)
                if not is_relevant:
                    continue
                if value is not None:
                    balance += value

                conf, timestamp = self.verifier.get_confirmations(tx_hash) if self.verifier else (None, None)
                result.append( (tx_hash, conf, is_mine, value, fee, balance, timestamp) )

        return result


    def get_label(self, tx_hash):
        label = self.labels.get(tx_hash)
        is_default = (label == '') or (label is None)
        if is_default: label = self.get_default_label(tx_hash)
        return label, is_default


    def get_default_label(self, tx_hash):
        tx = self.transactions.get(tx_hash)
        default_label = ''
        if tx:
            is_relevant, is_mine, _, _ = self.get_tx_value(tx)
            if is_mine:
                for o in tx.outputs:
                    o_addr, _ = o
                    if not self.is_mine(o_addr):
                        try:
                            default_label = self.labels[o_addr]
                        except KeyError:
                            default_label = o_addr
                        break
                else:
                    default_label = '(internal)'
            else:
                for o in tx.outputs:
                    o_addr, _ = o
                    if self.is_mine(o_addr) and not self.is_change(o_addr):
                        break
                else:
                    for o in tx.outputs:
                        o_addr, _ = o
                        if self.is_mine(o_addr):
                            break
                    else:
                        o_addr = None

                if o_addr:
                    dest_label = self.labels.get(o_addr)
                    try:
                        default_label = self.labels[o_addr]
                    except KeyError:
                        default_label = o_addr

        return default_label


    def make_unsigned_transaction(self, outputs, fee=None, change_addr=None, domain=None ):
        for address, x in outputs:
            assert is_valid(address)
        amount = sum( map(lambda x:x[1], outputs) )
        inputs, total, fee = self.choose_tx_inputs( amount, fee, domain )
        if not inputs:
            raise ValueError("Not enough funds")
        self.add_input_info(inputs)
        outputs = self.add_tx_change(inputs, outputs, amount, fee, total, change_addr)
        return Transaction.from_io(inputs, outputs)


    def mktx_from_account(self, outputs, password, fee=None, account=None):
        domain = self.get_account_addresses(account) if account else None
        return self.mktx(outputs, password, fee, change_addr=None, domain=domain)


    def mktx(self, outputs, password, fee=None, change_addr=None, domain= None ):
        tx = self.make_unsigned_transaction(outputs, fee, change_addr, domain)
        keypairs = {}
        self.add_keypairs_from_wallet(tx, keypairs, password)
        if keypairs:
            self.sign_transaction(tx, keypairs)
        return tx


    def add_input_info(self, inputs):
        for txin in inputs:
            address = txin['address']
            if address in self.imported_keys.keys():
                continue
            account, sequence = self.get_address_index(address)
            txin['KeyID'] = self.get_keyID(account, sequence)
            redeemScript = self.accounts[account].redeem_script(sequence)
            if redeemScript: 
                txin['redeemScript'] = redeemScript
            else:
                txin['redeemPubkey'] = self.accounts[account].get_pubkey(*sequence)


    def sign_transaction(self, tx, keypairs):
        tx.sign(keypairs)
        run_hook('sign_transaction', tx)


    def sendtx(self, tx):
        # synchronous
        h = self.send_tx(tx)
        self.tx_event.wait()
        return self.receive_tx(h)

    def send_tx(self, tx):
        # asynchronous
        self.tx_event.clear()
        self.network.interface.send([('blockchain.transaction.broadcast', [str(tx)])], self.on_broadcast)
        return tx.hash()

    def on_broadcast(self, i, r):
        self.tx_result = r.get('result')
        self.tx_event.set()

    def receive_tx(self,tx_hash):
        out = self.tx_result 
        if out != tx_hash:
            return False, "error: " + out
        return True, out



    def update_password(self, old_password, new_password):
        if new_password == '': new_password = None
        # this will throw an exception if unicode cannot be converted
        decoded = pw_decode(self.seed, old_password)
        self.seed = pw_encode( decoded, new_password)
        self.storage.put('seed', self.seed, True)
        self.use_encryption = (new_password != None)
        self.storage.put('use_encryption', self.use_encryption,True)
        for k in self.imported_keys.keys():
            a = self.imported_keys[k]
            b = pw_decode(a, old_password)
            c = pw_encode(b, new_password)
            self.imported_keys[k] = c
        self.storage.put('imported_keys', self.imported_keys, True)

        for k, v in self.master_private_keys.items():
            b = pw_decode(v, old_password)
            c = pw_encode(b, new_password)
            self.master_private_keys[k] = c
        self.storage.put('master_private_keys', self.master_private_keys, True)


    def freeze(self,addr):
        if self.is_mine(addr) and addr not in self.frozen_addresses:
            self.unprioritize(addr)
            self.frozen_addresses.append(addr)
            self.storage.put('frozen_addresses', self.frozen_addresses, True)
            return True
        else:
            return False

    def unfreeze(self,addr):
        if self.is_mine(addr) and addr in self.frozen_addresses:
            self.frozen_addresses.remove(addr)
            self.storage.put('frozen_addresses', self.frozen_addresses, True)
            return True
        else:
            return False

    def prioritize(self,addr):
        if self.is_mine(addr) and addr not in self.prioritized_addresses:
            self.unfreeze(addr)
            self.prioritized_addresses.append(addr)
            self.storage.put('prioritized_addresses', self.prioritized_addresses, True)
            return True
        else:
            return False

    def unprioritize(self,addr):
        if self.is_mine(addr) and addr in self.prioritized_addresses:
            self.prioritized_addresses.remove(addr)
            self.storage.put('prioritized_addresses', self.prioritized_addresses, True)
            return True
        else:
            return False


    def set_verifier(self, verifier):
        self.verifier = verifier

        # review transactions that are in the history
        for addr, hist in self.history.items():
            if hist == ['*']: continue
            for tx_hash, tx_height in hist:
                if tx_height>0:
                    # add it in case it was previously unconfirmed
                    self.verifier.add(tx_hash, tx_height)


        # if we are on a pruning server, remove unverified transactions
        vr = self.verifier.transactions.keys() + self.verifier.verified_tx.keys()
        for tx_hash in self.transactions.keys():
            if tx_hash not in vr:
                self.transactions.pop(tx_hash)



    def check_new_history(self, addr, hist):
        
        # check that all tx in hist are relevant
        if hist != ['*']:
            for tx_hash, height in hist:
                tx = self.transactions.get(tx_hash)
                if not tx: continue
                if not tx.has_address(addr):
                    return False

        # check that we are not "orphaning" a transaction
        old_hist = self.history.get(addr,[])
        if old_hist == ['*']: return True

        for tx_hash, height in old_hist:
            if tx_hash in map(lambda x:x[0], hist): continue
            found = False
            for _addr, _hist in self.history.items():
                if _addr == addr: continue
                if _hist == ['*']: continue
                _tx_hist = map(lambda x:x[0], _hist)
                if tx_hash in _tx_hist:
                    found = True
                    break

            if not found:
                tx = self.transactions.get(tx_hash)
                # tx might not be there
                if not tx: continue
                
                # already verified?
                if self.verifier.get_height(tx_hash):
                    continue
                # unconfirmed tx
                print_error("new history is orphaning transaction:", tx_hash)
                # check that all outputs are not mine, request histories
                ext_requests = []
                for _addr, _v in tx.outputs:
                    # assert not self.is_mine(_addr)
                    ext_requests.append( ('blockchain.address.get_history', [_addr]) )

                ext_h = self.network.synchronous_get(ext_requests)
                print_error("sync:", ext_requests, ext_h)
                height = None
                for h in ext_h:
                    if h == ['*']: continue
                    for item in h:
                        if item.get('tx_hash') == tx_hash:
                            height = item.get('height')
                if height:
                    print_error("found height for", tx_hash, height)
                    self.verifier.add(tx_hash, height)
                else:
                    print_error("removing orphaned tx from history", tx_hash)
                    self.transactions.pop(tx_hash)

        return True



    def check_new_tx(self, tx_hash, tx):
        # 1 check that tx is referenced in addr_history. 
        addresses = []
        for addr, hist in self.history.items():
            if hist == ['*']:continue
            for txh, height in hist:
                if txh == tx_hash: 
                    addresses.append(addr)

        if not addresses:
            return False

        # 2 check that referencing addresses are in the tx
        for addr in addresses:
            if not tx.has_address(addr):
                return False

        return True


    def start_threads(self, network):
        from verifier import TxVerifier
        self.network = network
        self.verifier = TxVerifier(self.network, self.storage)
        self.verifier.start()
        self.set_verifier(self.verifier)
        self.synchronizer = WalletSynchronizer(self, network)
        self.synchronizer.start()

    def stop_threads(self):
        self.verifier.stop()
        self.synchronizer.stop()



    def restore(self, callback):
        from i18n import _
        def wait_for_wallet():
            self.set_up_to_date(False)
            while not self.is_up_to_date():
                msg = "%s\n%s %d\n%s %.1f"%(
                    _("Please wait..."),
                    _("Addresses generated:"),
                    len(self.addresses(True)),_("Kilobytes received:"), 
                    self.network.interface.bytes_received/1024.)

                apply(callback, (msg,))
                time.sleep(0.1)

        def wait_for_network():
            while not self.network.is_connected():
                msg = "%s \n" % (_("Connecting..."))
                apply(callback, (msg,))
                time.sleep(0.1)

        # wait until we are connected, because the user might have selected another server
        wait_for_network()


        self.create_accounts()
        wait_for_wallet()




class WalletSynchronizer(threading.Thread):


    def __init__(self, wallet, network):
        threading.Thread.__init__(self)
        self.daemon = True
        self.wallet = wallet
        self.network = network
        self.was_updated = True
        self.running = False
        self.lock = threading.Lock()
        self.queue = Queue.Queue()

    def stop(self):
        with self.lock: self.running = False

    def is_running(self):
        with self.lock: return self.running

    
    def subscribe_to_addresses(self, addresses):
        messages = []
        for addr in addresses:
            messages.append(('blockchain.address.subscribe', [addr]))
        self.network.subscribe( messages, lambda i,r: self.queue.put(r))


    def run(self):
        with self.lock:
            self.running = True

        while self.is_running():
            
            if not self.network.is_connected():
                print_error("synchronizer: waiting for interface")
                self.network.wait_until_connected()
                
            self.run_interface(self.network.interface)


    def run_interface(self, interface):

        print_error("synchronizer: connected to", interface.server)

        requested_tx = []
        missing_tx = []
        requested_histories = {}

        # request any missing transactions
        for history in self.wallet.history.values():
            if history == ['*']: continue
            for tx_hash, tx_height in history:
                if self.wallet.transactions.get(tx_hash) is None and (tx_hash, tx_height) not in missing_tx:
                    missing_tx.append( (tx_hash, tx_height) )

        if missing_tx:
            print_error("missing tx", missing_tx)

        # subscriptions
        self.subscribe_to_addresses(self.wallet.addresses(True))

        while self.is_running():
            # 1. create new addresses
            new_addresses = self.wallet.synchronize()

            # request missing addresses
            if new_addresses:
                self.subscribe_to_addresses(new_addresses)

            # request missing transactions
            for tx_hash, tx_height in missing_tx:
                if (tx_hash, tx_height) not in requested_tx:
                    interface.send([ ('blockchain.transaction.get',[tx_hash, tx_height]) ], lambda i,r: self.queue.put(r))
                    requested_tx.append( (tx_hash, tx_height) )
            missing_tx = []

            # detect if situation has changed
            if interface.is_up_to_date() and self.queue.empty():
                if not self.wallet.is_up_to_date():
                    self.wallet.set_up_to_date(True)
                    self.was_updated = True
            else:
                if self.wallet.is_up_to_date():
                    self.wallet.set_up_to_date(False)
                    self.was_updated = True

            if self.was_updated:
                self.wallet.network.trigger_callback('updated')
                self.was_updated = False

            # 2. get a response
            try:
                r = self.queue.get(block=True, timeout=1)
            except Queue.Empty:
                continue

            if interface != self.network.interface:
                break
            
            if not r:
                continue

            # 3. handle response
            method = r['method']
            params = r['params']
            result = r.get('result')
            error = r.get('error')
            if error:
                print "error", r
                continue

            if method == 'blockchain.address.subscribe':
                addr = params[0]
                if self.wallet.get_status(self.wallet.get_history(addr)) != result:
                    if requested_histories.get(addr) is None:
                        interface.send([('blockchain.address.get_history', [addr])], lambda i,r:self.queue.put(r))
                        requested_histories[addr] = result

            elif method == 'blockchain.address.get_history':
                addr = params[0]
                print_error("receiving history", addr, result)
                if result == ['*']:
                    assert requested_histories.pop(addr) == '*'
                    self.wallet.receive_history_callback(addr, result)
                else:
                    hist = []
                    # check that txids are unique
                    txids = []
                    for item in result:
                        tx_hash = item['tx_hash']
                        if tx_hash not in txids:
                            txids.append(tx_hash)
                            hist.append( (tx_hash, item['height']) )

                    if len(hist) != len(result):
                        raise BaseException("error: server sent history with non-unique txid", result)

                    # check that the status corresponds to what was announced
                    rs = requested_histories.pop(addr)
                    if self.wallet.get_status(hist) != rs:
                        raise BaseException("error: status mismatch: %s"%addr)
                
                    # store received history
                    self.wallet.receive_history_callback(addr, hist)

                    # request transactions that we don't have 
                    for tx_hash, tx_height in hist:
                        if self.wallet.transactions.get(tx_hash) is None:
                            if (tx_hash, tx_height) not in requested_tx and (tx_hash, tx_height) not in missing_tx:
                                missing_tx.append( (tx_hash, tx_height) )

            elif method == 'blockchain.transaction.get':
                tx_hash = params[0]
                tx_height = params[1]
                assert tx_hash == hash_encode(Hash(result.decode('hex')))
                tx = Transaction(result)
                self.wallet.receive_tx_callback(tx_hash, tx, tx_height)
                self.was_updated = True
                requested_tx.remove( (tx_hash, tx_height) )
                print_error("received tx:", tx_hash, len(tx.raw))

            else:
                print_error("Error: Unknown message:" + method + ", " + repr(params) + ", " + repr(result) )

            if self.was_updated and not requested_tx:
                self.wallet.network.trigger_callback('updated')
                self.wallet.network.trigger_callback("new_transaction") # Updated gets called too many times from other places as well; if we use that signal we get the notification three times

                self.was_updated = False