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, user_dir, format_satoshis
from bitcoin import *

# URL decode
_ud = re.compile('%([0-9a-hA-H]{2})', re.MULTILINE)
urldecode = lambda x: _ud.sub(lambda m: chr(int(m.group(1), 16)), x)

# 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 ELECTRUM_VERSION, SEED_VERSION


class Wallet:
    def __init__(self, config={}):

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

        # saved fields
        self.seed_version          = config.get('seed_version', SEED_VERSION)
        self.gap_limit             = config.get('gap_limit', 5)
        self.use_change            = config.get('use_change',True)
        self.fee                   = int(config.get('fee',100000))
        self.num_zeros             = int(config.get('num_zeros',0))
        self.use_encryption        = config.get('use_encryption', False)
        self.seed                  = config.get('seed', '')               # encrypted
        self.labels                = config.get('labels', {})
        self.aliases               = config.get('aliases', {})            # aliases for addresses
        self.authorities           = config.get('authorities', {})        # trusted addresses
        self.frozen_addresses      = config.get('frozen_addresses',[])
        self.prioritized_addresses = config.get('prioritized_addresses',[])
        self.receipts              = config.get('receipts',{})            # signed URIs
        self.addressbook           = config.get('contacts', [])
        self.imported_keys         = config.get('imported_keys',{})
        self.history               = config.get('addr_history',{})        # address -> list(txid, height)
        self.tx_height             = config.get('tx_height',{})
        self.requested_amounts     = config.get('requested_amounts',{}) 
        self.accounts              = config.get('accounts', {})   # this should not include public keys
        self.sequences = {}

        mpk1 = self.config.get('master_public_key')
        self.sequences[0] = DeterministicSequence(mpk1)
        if self.accounts.get(0) is None:
            self.accounts[0] = { 0:[], 1:[], 'name':'Main account' }


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


        # not saved
        self.prevout_values = {}     # my own transaction outputs
        self.spent_outputs = []
        self.receipt = None          # next receipt
        self.banner = ''

        # 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.tx_event = threading.Event()

        if self.seed_version != SEED_VERSION:
            raise ValueError("This wallet seed is deprecated. Please run upgrade.py for a diagnostic.")

        for tx_hash in self.transactions.keys():
            self.update_tx_outputs(tx_hash)


    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
        self.interface.poke('synchronizer')
        while not self.is_up_to_date(): time.sleep(0.1)

    def import_key(self, sec, password):
        # check password
        seed = self.decode_seed(password)
        address = address_from_private_key(sec)

        if address in self.all_addresses():
            raise BaseException('Address already in wallet')
        
        # store the originally requested keypair into the imported keys table
        self.imported_keys[address] = pw_encode(sec, password )
        return address
        

    def init_seed(self, seed):
        if self.seed: raise BaseException("a seed exists")
        if not seed: 
            seed = random_seed(128)
        self.seed = seed 
        self.config.set_key('seed', self.seed, True)
        self.config.set_key('seed_version', self.seed_version, True)

        self.init_main_account(self.seed)
        

    def init_main_account(self, seed):
        # public key
        sequence = DeterministicSequence.from_seed(seed)
        self.accounts[0] = { 0:[], 1:[], 'name':'Main account' }
        self.sequences[0] = sequence
        self.config.set_key('accounts', self.accounts, True)



    def all_addresses(self):
        o = self.imported_keys.keys()
        for a in self.accounts.values():
            o += a[0]
            o += a[1]
        return o


    def is_mine(self, address):
        return address in self.all_addresses()

    def is_change(self, address):
        #return address in self.change_addresses
        return False

    def get_master_public_key(self):
        return self.sequence.master_public_key

    def get_address_index(self, address):
        if address in self.imported_keys.keys():
            raise BaseException("imported key")
        for account in self.accounts.keys():
            for for_change in [0,1]:
                addresses = self.accounts[account][for_change]
                for addr in addresses:
                    if address == addr:
                        return account, for_change, addresses.index(addr)
        raise BaseException("not found")
        

    def get_public_key(self, address):
        account, n, for_change = self.get_address_index(address)
        return self.sequences[account].get_pubkey(n, for_change)


    def decode_seed(self, password):
        seed = pw_decode(self.seed, password)
        self.sequences[0].check_seed(seed)
        return seed
        
    def get_private_key(self, address, password):
        return self.get_private_keys([address], password).get(address)

    def get_private_keys(self, addresses, password):
        # decode seed in any case, in order to test the password
        seed = self.decode_seed(password)
        secexp = self.sequences[0].stretch_key(seed)
        out = {}
        for address in addresses:
            if address in self.imported_keys.keys():
                out[address] = pw_decode( self.imported_keys[address], password )
            else:
                account, for_change, n = self.get_address_index(address)
                if account == 0:
                    out[address] = self.sequences[0].get_private_key_from_stretched_exponent(n, for_change, secexp)
        return out


    def signrawtransaction(self, tx, input_info, private_keys, password):
        unspent_coins = self.get_unspent_coins()
        seed = self.decode_seed(password)

        # convert private_keys to dict 
        pk = {}
        for sec in private_keys:
            address = address_from_private_key(sec)
            pk[address] = sec
        private_keys = pk

        for txin in tx.inputs:
            # convert to own format
            txin['tx_hash'] = txin['prevout_hash']
            txin['index'] = txin['prevout_n']

            for item in input_info:
                if item.get('txid') == txin['tx_hash'] and item.get('vout') == txin['index']:
                    txin['raw_output_script'] = item['scriptPubKey']
                    txin['redeemScript'] = item.get('redeemScript')
                    txin['electrumKeyID'] = item.get('electrumKeyID')
                    break
            else:
                for item in unspent_coins:
                    if txin['tx_hash'] == item['tx_hash'] and txin['index'] == item['index']:
                        txin['raw_output_script'] = item['raw_output_script']
                        break
                else:
                    # if neither, we might want to get it from the server..
                    raise

            # find the address:
            if txin.get('electrumKeyID'):
                account, for_change, n = txin.get('electrumKeyID')
                sec = self.sequences[account].get_private_key(n, for_change, seed)
                addr = self.sequences[account].get_address(n, for_change)
                txin['address'] = addr
                private_keys[addr] = sec

            elif txin.get("redeemScript"):
                txin['address'] = hash_160_to_bc_address(hash_160(txin.get("redeemScript").decode('hex')), 5)

            elif txin.get("raw_output_script"):
                import deserialize
                addr = deserialize.get_address_from_output_script(txin.get("raw_output_script").decode('hex'))
                sec = self.get_private_key(addr, password)
                if sec: 
                    private_keys[addr] = sec
                    txin['address'] = addr

        tx.sign( private_keys )

    def sign_message(self, address, message, password):
        sec = self.get_private_key(address, password)
        key = regenerate_key(sec)
        compressed = is_compressed(sec)
        return key.sign_message(message, compressed, address)


    def create_new_address(self, account, for_change):
        addresses = self.accounts[account][for_change]
        n = len(addresses)
        address = self.get_new_address( account, for_change, n)
        self.accounts[account][for_change].append(address)
        self.history[address] = []
        return address
        

    def get_new_address(self, account, for_change, n):
        return self.sequences[account].get_address(for_change, n)
        print_msg( address )
        return address

    def change_gap_limit(self, value):
        if value >= self.gap_limit:
            self.gap_limit = value
            self.save()
            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.save()
            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[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.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
        addresses = self.accounts[account][for_change]
        new_addresses = []
        while True:
            if len(addresses) < limit:
                new_addresses.append( self.create_new_address(account, for_change) )
                continue
            if map( lambda a: self.address_is_old(a), addresses[-limit:] ) == limit*[False]:
                break
            else:
                new_addresses.append( self.create_new_address(account, for_change) )
        return new_addresses
        

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

    def synchronize(self):
        new = []
        for account in self.accounts.keys():
            new += self.synchronize_account(account)
        return new


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


    def fill_addressbook(self):
        for tx_hash, tx in self.transactions.items():
            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_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, addresses=None):
        if addresses is None: addresses = self.all_addresses()
        return tx.get_value(addresses, self.prevout_values)


    def get_tx_details(self, tx_hash):
        import datetime
        if not tx_hash: return ''
        tx = self.transactions.get(tx_hash)
        is_mine, v, fee = self.get_tx_value(tx)
        conf, timestamp = self.verifier.get_confirmations(tx_hash)

        if timestamp:
            time_str = datetime.datetime.fromtimestamp(timestamp).isoformat(' ')[:-3]
        else:
            time_str = 'pending'

        inputs = map(lambda x: x.get('address'), tx.inputs)
        outputs = map(lambda x: x.get('address'), tx.d['outputs'])
        tx_details = "Transaction Details" +"\n\n" \
            + "Transaction ID:\n" + tx_hash + "\n\n" \
            + "Status: %d confirmations\n"%conf
        if is_mine:
            if fee: 
                tx_details += "Amount sent: %s\n"% format_satoshis(v-fee, False) \
                              + "Transaction fee: %s\n"% format_satoshis(fee, False)
            else:
                tx_details += "Amount sent: %s\n"% format_satoshis(v, False) \
                              + "Transaction fee: unknown\n"
        else:
            tx_details += "Amount received: %s\n"% format_satoshis(v, False) \

        tx_details += "Date: %s\n\n"%time_str \
            + "Inputs:\n-"+ '\n-'.join(inputs) + "\n\n" \
            + "Outputs:\n-"+ '\n-'.join(outputs)

        r = self.receipts.get(tx_hash)
        if r:
            tx_details += "\n_______________________________________" \
                + '\n\nSigned URI: ' + r[2] \
                + "\n\nSigned by: " + r[0] \
                + '\n\nSignature: ' + r[1]

        return tx_details

    
    def update_tx_outputs(self, tx_hash):
        tx = self.transactions.get(tx_hash)
        i = 0
        for item in tx.outputs:
            addr, value = item
            key = tx_hash+ ':%d'%i
            with self.lock:
                self.prevout_values[key] = value
            i += 1

        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
            i = 0
            for item in tx.outputs:
                addr, value = item
                if addr == address:
                    key = tx_hash + ':%d'%i
                    received_coins.append(key)
                i +=1

        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

            i = 0
            for item in tx.outputs:
                addr, value = item
                key = tx_hash + ':%d'%i
                if addr == address:
                    v += value
                i += 1

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

    def get_account_addresses(self, a):
        ac = self.accounts[a]
        return ac[0] + ac[1]
        

    def get_account_balance(self, account):
        conf = unconf = 0
        for addr in self.get_account_addresses(account): 
            c, u = self.get_addr_balance(addr)
            conf += c
            unconf += u
        return conf, unconf

    def get_balance(self):
        cc = uu = 0
        for a in self.accounts.keys():
            c, u = self.get_account_balance(a)
            cc += c
            uu += u
        return cc, uu


    def get_unspent_coins(self, domain=None):
        coins = []
        if domain is None: domain = self.all_addresses()
        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)
                for output in tx.d.get('outputs'):
                    if output.get('address') != addr: continue
                    key = tx_hash + ":%d" % output.get('index')
                    if key in self.spent_outputs: continue
                    output['tx_hash'] = tx_hash
                    coins.append(output)
        return coins



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

        coins = []
        prioritized_coins = []
        domain = [from_addr] if from_addr else self.all_addresses()
        for i in self.frozen_addresses:
            if i in domain: domain.remove(i)

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

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

        inputs = []
        coins = prioritized_coins + coins

        for item in coins: 
            addr = item.get('address')
            v = item.get('value')
            total += v

            inputs.append( item )
            fee = self.fee*len(inputs) if fixed_fee is None else fixed_fee
            if total >= amount + fee: break
        else:
            #print "not enough funds: %s %s"%(format_satoshis(total), format_satoshis(fee))
            inputs = []
        return inputs, total, fee

    def add_tx_change( self, outputs, amount, fee, total, change_addr=None ):
        change_amount = total - ( amount + fee )
        if change_amount != 0:
            # normally, the update thread should ensure that the last change address is unused
            if not change_addr:
                change_addr = self.change_addresses[-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):

        if not self.check_new_tx(tx_hash, tx):
            raise BaseException("error: received transaction is not consistent with history"%tx_hash)

        with self.lock:
            self.transactions[tx_hash] = tx
            self.tx_height[tx_hash] = tx_height

        #tx_height = tx.get('height')
        if self.verifier and tx_height>0: 
            self.verifier.add(tx_hash, tx_height)

        self.update_tx_outputs(tx_hash)

        self.save()


    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.save()

        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)
                    # set the height in case it changed
                    txh = self.tx_height.get(tx_hash)
                    if txh is not None and txh != tx_height:
                        print_error( "changing height for tx", tx_hash )
                        self.tx_height[tx_hash] = tx_height


    def get_tx_history(self):
        with self.lock:
            history = self.transactions.items()
        history.sort(key = lambda x: self.tx_height.get(x[0]) if self.tx_height.get(x[0]) else 1e12)
        result = []
    
        balance = 0
        for tx_hash, tx in history:
            is_mine, v, fee = self.get_tx_value(tx)
            if v is not None: balance += v
        c, u = self.get_balance()

        if balance != c+u:
            v_str = format_satoshis( c+u - balance, True, self.num_zeros)
            result.append( ('', 1000, 0, c+u-balance, None, c+u-balance, None ) )

        balance = c + u - balance
        for tx_hash, tx in history:
            conf, timestamp = self.verifier.get_confirmations(tx_hash) if self.verifier else (None, None)
            is_mine, value, fee = self.get_tx_value(tx)
            if value is not None:
                balance += value

            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_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
            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 mktx(self, outputs, password, fee=None, change_addr=None, from_addr= 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, from_addr )
        if not inputs:
            raise ValueError("Not enough funds")

        if not self.use_change and not change_addr:
            change_addr = inputs[-1]['address']
            print_error( "Sending change to", change_addr )
        outputs = self.add_tx_change(outputs, amount, fee, total, change_addr)

        tx = Transaction.from_io(inputs, outputs)

        pk_addresses = []
        for i in range(len(tx.inputs)):
            txin = tx.inputs[i]
            account, is_change, n = self.get_address_index(txin['address'])
            pk_addr = self.sequences[account].add_input_info(txin, account, is_change, n)
            pk_addresses.append(pk_addr)

        # get all private keys at once.
        private_keys = self.get_private_keys(pk_addresses, password)
        print "private keys", private_keys
        tx.sign(private_keys)

        for address, x in outputs:
            if address not in self.addressbook and not self.is_mine(address):
                self.addressbook.append(address)

        return 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.interface.send([('blockchain.transaction.broadcast', [str(tx)])], 'synchronizer')
        return tx.hash()

    def receive_tx(self,tx_hash):
        out = self.tx_result 
        if out != tx_hash:
            return False, "error: " + out
        if self.receipt:
            self.receipts[tx_hash] = self.receipt
            self.receipt = None
        return True, out


    def read_alias(self, alias):
        # this might not be the right place for this function.
        import urllib

        m1 = re.match('([\w\-\.]+)@((\w[\w\-]+\.)+[\w\-]+)', alias)
        m2 = re.match('((\w[\w\-]+\.)+[\w\-]+)', alias)
        if m1:
            url = 'https://' + m1.group(2) + '/bitcoin.id/' + m1.group(1) 
        elif m2:
            url = 'https://' + alias + '/bitcoin.id'
        else:
            return ''
        try:
            lines = urllib.urlopen(url).readlines()
        except:
            return ''

        # line 0
        line = lines[0].strip().split(':')
        if len(line) == 1:
            auth_name = None
            target = signing_addr = line[0]
        else:
            target, auth_name, signing_addr, signature = line
            msg = "alias:%s:%s:%s"%(alias,target,auth_name)
            print msg, signature
            EC_KEY.verify_message(signing_addr, signature, msg)
        
        # other lines are signed updates
        for line in lines[1:]:
            line = line.strip()
            if not line: continue
            line = line.split(':')
            previous = target
            print repr(line)
            target, signature = line
            EC_KEY.verify_message(previous, signature, "alias:%s:%s"%(alias,target))

        if not is_valid(target):
            raise ValueError("Invalid bitcoin address")

        return target, signing_addr, auth_name

    def update_password(self, seed, old_password, new_password):
        if new_password == '': new_password = None
        self.use_encryption = (new_password != None)
        self.seed = pw_encode( seed, new_password)
        self.config.set_key('seed', self.seed, 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.save()

    def get_alias(self, alias, interactive = False, show_message=None, question = None):
        try:
            target, signing_address, auth_name = self.read_alias(alias)
        except BaseException, e:
            # raise exception if verify fails (verify the chain)
            if interactive:
                show_message("Alias error: " + str(e))
            return

        print target, signing_address, auth_name

        if auth_name is None:
            a = self.aliases.get(alias)
            if not a:
                msg = "Warning: the alias '%s' is self-signed.\nThe signing address is %s.\n\nDo you want to add this alias to your list of contacts?"%(alias,signing_address)
                if interactive and question( msg ):
                    self.aliases[alias] = (signing_address, target)
                else:
                    target = None
            else:
                if signing_address != a[0]:
                    msg = "Warning: the key of alias '%s' has changed since your last visit! It is possible that someone is trying to do something nasty!!!\nDo you accept to change your trusted key?"%alias
                    if interactive and question( msg ):
                        self.aliases[alias] = (signing_address, target)
                    else:
                        target = None
        else:
            if signing_address not in self.authorities.keys():
                msg = "The alias: '%s' links to %s\n\nWarning: this alias was signed by an unknown key.\nSigning authority: %s\nSigning address: %s\n\nDo you want to add this key to your list of trusted keys?"%(alias,target,auth_name,signing_address)
                if interactive and question( msg ):
                    self.authorities[signing_address] = auth_name
                else:
                    target = None

        if target:
            self.aliases[alias] = (signing_address, target)
            
        return target


    def parse_url(self, url, show_message, question):
        o = url[8:].split('?')
        address = o[0]
        if len(o)>1:
            params = o[1].split('&')
        else:
            params = []

        amount = label = message = signature = identity = ''
        for p in params:
            k,v = p.split('=')
            uv = urldecode(v)
            if k == 'amount': amount = uv
            elif k == 'message': message = uv
            elif k == 'label': label = uv
            elif k == 'signature':
                identity, signature = uv.split(':')
                url = url.replace('&%s=%s'%(k,v),'')
            else: 
                print k,v

        if label and self.labels.get(address) != label:
            if question('Give label "%s" to address %s ?'%(label,address)):
                if address not in self.addressbook and address not in self.all_addresses(): 
                    self.addressbook.append(address)
                self.labels[address] = label

        if signature:
            if re.match('^(|([\w\-\.]+)@)((\w[\w\-]+\.)+[\w\-]+)$', identity):
                signing_address = self.get_alias(identity, True, show_message, question)
            elif is_valid(identity):
                signing_address = identity
            else:
                signing_address = None
            if not signing_address:
                return
            try:
                EC_KEY.verify_message(signing_address, signature, url )
                self.receipt = (signing_address, signature, url)
            except:
                show_message('Warning: the URI contains a bad signature.\nThe identity of the recipient cannot be verified.')
                address = amount = label = identity = message = ''

        if re.match('^(|([\w\-\.]+)@)((\w[\w\-]+\.)+[\w\-]+)$', address):
            payto_address = self.get_alias(address, True, show_message, question)
            if payto_address:
                address = address + ' <' + payto_address + '>'

        return address, amount, label, message, signature, identity, url



    def freeze(self,addr):
        if addr in self.all_addresses() and addr not in self.frozen_addresses:
            self.unprioritize(addr)
            self.frozen_addresses.append(addr)
            self.config.set_key('frozen_addresses', self.frozen_addresses, True)
            return True
        else:
            return False

    def unfreeze(self,addr):
        if addr in self.all_addresses() and addr in self.frozen_addresses:
            self.frozen_addresses.remove(addr)
            self.config.set_key('frozen_addresses', self.frozen_addresses, True)
            return True
        else:
            return False

    def prioritize(self,addr):
        if addr in self.all_addresses() and addr not in self.prioritized_addresses:
            self.unfreeze(addr)
            self.prioritized_addresses.append(addr)
            self.config.set_key('prioritized_addresses', self.prioritized_addresses, True)
            return True
        else:
            return False

    def unprioritize(self,addr):
        if addr in self.all_addresses() and addr in self.prioritized_addresses:
            self.prioritized_addresses.remove(addr)
            self.config.set_key('prioritized_addresses', self.prioritized_addresses, True)
            return True
        else:
            return False

    def save(self):
        tx = {}
        for k,v in self.transactions.items():
            tx[k] = str(v)
            
        s = {
            'use_encryption': self.use_encryption,
            'use_change': self.use_change,
            'fee': self.fee,
            'accounts': self.accounts,
            'addr_history': self.history, 
            'labels': self.labels,
            'contacts': self.addressbook,
            'imported_keys': self.imported_keys,
            'aliases': self.aliases,
            'authorities': self.authorities,
            'receipts': self.receipts,
            'num_zeros': self.num_zeros,
            'frozen_addresses': self.frozen_addresses,
            'prioritized_addresses': self.prioritized_addresses,
            'gap_limit': self.gap_limit,
            'transactions': tx,
            'tx_height': self.tx_height,
            'requested_amounts': self.requested_amounts,
        }
        for k, v in s.items():
            self.config.set_key(k,v)
        self.config.save()

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

        # review stored transactions and send them to the verifier
        # (they are not necessarily in the history, because history items might have have been pruned)
        for tx_hash, tx in self.transactions.items():
            tx_height = self.tx_height[tx_hash]
            if tx_height <1:
                print_error( "skipping", tx_hash, tx_height )
                continue
            
            if tx_height>0:
                self.verifier.add(tx_hash, tx_height)

        # 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)
                    # set the height in case it changed
                    txh = self.tx_height.get(tx_hash)
                    if txh is not None and txh != tx_height:
                        print_error( "changing height for tx", tx_hash )
                        self.tx_height[tx_hash] = tx_height




    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.tx_height.get(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 o in tx.get('outputs'):
                    _addr = o.get('address')
                    # assert not self.is_mine(_addr)
                    ext_requests.append( ('blockchain.address.get_history', [_addr]) )

                ext_h = self.interface.synchronous_get(ext_requests)
                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')
                            self.tx_height[tx_hash] = 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




class WalletSynchronizer(threading.Thread):


    def __init__(self, wallet, config):
        threading.Thread.__init__(self)
        self.daemon = True
        self.wallet = wallet
        self.interface = self.wallet.interface
        self.interface.register_channel('synchronizer')
        self.wallet.interface.register_callback('connected', lambda: self.wallet.set_up_to_date(False))
        self.wallet.interface.register_callback('connected', lambda: self.interface.send([('server.banner',[])],'synchronizer') )
        self.was_updated = True
        self.running = False
        self.lock = threading.Lock()

    def stop(self):
        with self.lock: self.running = False
        self.interface.poke('synchronizer')

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

    def synchronize_wallet(self):
        new_addresses = self.wallet.synchronize()
        if new_addresses:
            self.subscribe_to_addresses(new_addresses)
            self.wallet.up_to_date = False
            return
            
        if not self.interface.is_up_to_date('synchronizer'):
            if self.wallet.is_up_to_date():
                self.wallet.set_up_to_date(False)
                self.was_updated = True
            return

        self.wallet.set_up_to_date(True)
        self.was_updated = True

    
    def subscribe_to_addresses(self, addresses):
        messages = []
        for addr in addresses:
            messages.append(('blockchain.address.subscribe', [addr]))
        self.interface.send( messages, 'synchronizer')


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

        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) )
        print_error("missing tx", missing_tx)

        # wait until we are connected, in case the user is not connected
        while not self.interface.is_connected:
            time.sleep(1)
        
        # request banner, because 'connected' event happens before this thread is started
        self.interface.send([('server.banner',[])],'synchronizer')

        # subscriptions
        self.subscribe_to_addresses(self.wallet.all_addresses())

        while self.is_running():
            # 1. send new requests
            self.synchronize_wallet()

            for tx_hash, tx_height in missing_tx:
                if (tx_hash, tx_height) not in requested_tx:
                    self.interface.send([ ('blockchain.transaction.get',[tx_hash, tx_height]) ], 'synchronizer')
                    requested_tx.append( (tx_hash, tx_height) )
            missing_tx = []

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

            # 2. get a response
            r = self.interface.get_response('synchronizer')

            # poke sends None. (needed during stop)
            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:
                        self.interface.send([('blockchain.address.get_history', [addr])], 'synchronizer')
                        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)

            elif method == 'blockchain.transaction.broadcast':
                self.wallet.tx_result = result
                self.wallet.tx_event.set()

            elif method == 'server.banner':
                self.wallet.banner = result
                self.interface.trigger_callback('banner')
            else:
                print_error("Error: Unknown message:" + method + ", " + repr(params) + ", " + repr(result) )

            if self.was_updated and not requested_tx:
                self.interface.trigger_callback('updated')
                self.was_updated = False