#!/usr/bin/env python
#
# Electrum - lightweight Bitcoin client
# Copyright (C) 2011 Thomas Voegtlin
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.



# Note: The deserialization code originally comes from ABE.


import bitcoin
from bitcoin import *
from bitcoin import hash160_to_p2sh, hash160_to_p2pkh
from util import print_error, profiler
import time
import sys
import struct

#
# Workalike python implementation of Bitcoin's CDataStream class.
#
import struct
import StringIO
import random
from keystore import xpubkey_to_address, xpubkey_to_pubkey

NO_SIGNATURE = 'ff'


class SerializationError(Exception):
    """ Thrown when there's a problem deserializing or serializing """

class BCDataStream(object):
    def __init__(self):
        self.input = None
        self.read_cursor = 0

    def clear(self):
        self.input = None
        self.read_cursor = 0

    def write(self, bytes):  # Initialize with string of bytes
        if self.input is None:
            self.input = bytes
        else:
            self.input += bytes

    def read_string(self):
        # Strings are encoded depending on length:
        # 0 to 252 :  1-byte-length followed by bytes (if any)
        # 253 to 65,535 : byte'253' 2-byte-length followed by bytes
        # 65,536 to 4,294,967,295 : byte '254' 4-byte-length followed by bytes
        # ... and the Bitcoin client is coded to understand:
        # greater than 4,294,967,295 : byte '255' 8-byte-length followed by bytes of string
        # ... but I don't think it actually handles any strings that big.
        if self.input is None:
            raise SerializationError("call write(bytes) before trying to deserialize")

        try:
            length = self.read_compact_size()
        except IndexError:
            raise SerializationError("attempt to read past end of buffer")

        return self.read_bytes(length)

    def write_string(self, string):
        # Length-encoded as with read-string
        self.write_compact_size(len(string))
        self.write(string)

    def read_bytes(self, length):
        try:
            result = self.input[self.read_cursor:self.read_cursor+length]
            self.read_cursor += length
            return result
        except IndexError:
            raise SerializationError("attempt to read past end of buffer")

        return ''

    def read_boolean(self): return self.read_bytes(1)[0] != chr(0)
    def read_int16(self): return self._read_num('<h')
    def read_uint16(self): return self._read_num('<H')
    def read_int32(self): return self._read_num('<i')
    def read_uint32(self): return self._read_num('<I')
    def read_int64(self): return self._read_num('<q')
    def read_uint64(self): return self._read_num('<Q')

    def write_boolean(self, val): return self.write(chr(1) if val else chr(0))
    def write_int16(self, val): return self._write_num('<h', val)
    def write_uint16(self, val): return self._write_num('<H', val)
    def write_int32(self, val): return self._write_num('<i', val)
    def write_uint32(self, val): return self._write_num('<I', val)
    def write_int64(self, val): return self._write_num('<q', val)
    def write_uint64(self, val): return self._write_num('<Q', val)

    def read_compact_size(self):
        size = ord(self.input[self.read_cursor])
        self.read_cursor += 1
        if size == 253:
            size = self._read_num('<H')
        elif size == 254:
            size = self._read_num('<I')
        elif size == 255:
            size = self._read_num('<Q')
        return size

    def write_compact_size(self, size):
        if size < 0:
            raise SerializationError("attempt to write size < 0")
        elif size < 253:
            self.write(chr(size))
        elif size < 2**16:
            self.write('\xfd')
            self._write_num('<H', size)
        elif size < 2**32:
            self.write('\xfe')
            self._write_num('<I', size)
        elif size < 2**64:
            self.write('\xff')
            self._write_num('<Q', size)

    def _read_num(self, format):
        (i,) = struct.unpack_from(format, self.input, self.read_cursor)
        self.read_cursor += struct.calcsize(format)
        return i

    def _write_num(self, format, num):
        s = struct.pack(format, num)
        self.write(s)

#
# enum-like type
# From the Python Cookbook, downloaded from http://code.activestate.com/recipes/67107/
#
import types, string, exceptions

class EnumException(exceptions.Exception):
    pass

class Enumeration:
    def __init__(self, name, enumList):
        self.__doc__ = name
        lookup = { }
        reverseLookup = { }
        i = 0
        uniqueNames = [ ]
        uniqueValues = [ ]
        for x in enumList:
            if type(x) == types.TupleType:
                x, i = x
            if type(x) != types.StringType:
                raise EnumException, "enum name is not a string: " + x
            if type(i) != types.IntType:
                raise EnumException, "enum value is not an integer: " + i
            if x in uniqueNames:
                raise EnumException, "enum name is not unique: " + x
            if i in uniqueValues:
                raise EnumException, "enum value is not unique for " + x
            uniqueNames.append(x)
            uniqueValues.append(i)
            lookup[x] = i
            reverseLookup[i] = x
            i = i + 1
        self.lookup = lookup
        self.reverseLookup = reverseLookup
    def __getattr__(self, attr):
        if not self.lookup.has_key(attr):
            raise AttributeError
        return self.lookup[attr]
    def whatis(self, value):
        return self.reverseLookup[value]


# This function comes from bitcointools, bct-LICENSE.txt.
def long_hex(bytes):
    return bytes.encode('hex_codec')

# This function comes from bitcointools, bct-LICENSE.txt.
def short_hex(bytes):
    t = bytes.encode('hex_codec')
    if len(t) < 11:
        return t
    return t[0:4]+"..."+t[-4:]



opcodes = Enumeration("Opcodes", [
    ("OP_0", 0), ("OP_PUSHDATA1",76), "OP_PUSHDATA2", "OP_PUSHDATA4", "OP_1NEGATE", "OP_RESERVED",
    "OP_1", "OP_2", "OP_3", "OP_4", "OP_5", "OP_6", "OP_7",
    "OP_8", "OP_9", "OP_10", "OP_11", "OP_12", "OP_13", "OP_14", "OP_15", "OP_16",
    "OP_NOP", "OP_VER", "OP_IF", "OP_NOTIF", "OP_VERIF", "OP_VERNOTIF", "OP_ELSE", "OP_ENDIF", "OP_VERIFY",
    "OP_RETURN", "OP_TOALTSTACK", "OP_FROMALTSTACK", "OP_2DROP", "OP_2DUP", "OP_3DUP", "OP_2OVER", "OP_2ROT", "OP_2SWAP",
    "OP_IFDUP", "OP_DEPTH", "OP_DROP", "OP_DUP", "OP_NIP", "OP_OVER", "OP_PICK", "OP_ROLL", "OP_ROT",
    "OP_SWAP", "OP_TUCK", "OP_CAT", "OP_SUBSTR", "OP_LEFT", "OP_RIGHT", "OP_SIZE", "OP_INVERT", "OP_AND",
    "OP_OR", "OP_XOR", "OP_EQUAL", "OP_EQUALVERIFY", "OP_RESERVED1", "OP_RESERVED2", "OP_1ADD", "OP_1SUB", "OP_2MUL",
    "OP_2DIV", "OP_NEGATE", "OP_ABS", "OP_NOT", "OP_0NOTEQUAL", "OP_ADD", "OP_SUB", "OP_MUL", "OP_DIV",
    "OP_MOD", "OP_LSHIFT", "OP_RSHIFT", "OP_BOOLAND", "OP_BOOLOR",
    "OP_NUMEQUAL", "OP_NUMEQUALVERIFY", "OP_NUMNOTEQUAL", "OP_LESSTHAN",
    "OP_GREATERTHAN", "OP_LESSTHANOREQUAL", "OP_GREATERTHANOREQUAL", "OP_MIN", "OP_MAX",
    "OP_WITHIN", "OP_RIPEMD160", "OP_SHA1", "OP_SHA256", "OP_HASH160",
    "OP_HASH256", "OP_CODESEPARATOR", "OP_CHECKSIG", "OP_CHECKSIGVERIFY", "OP_CHECKMULTISIG",
    "OP_CHECKMULTISIGVERIFY",
    ("OP_SINGLEBYTE_END", 0xF0),
    ("OP_DOUBLEBYTE_BEGIN", 0xF000),
    "OP_PUBKEY", "OP_PUBKEYHASH",
    ("OP_INVALIDOPCODE", 0xFFFF),
])


def script_GetOp(bytes):
    i = 0
    while i < len(bytes):
        vch = None
        opcode = ord(bytes[i])
        i += 1
        if opcode >= opcodes.OP_SINGLEBYTE_END:
            opcode <<= 8
            opcode |= ord(bytes[i])
            i += 1

        if opcode <= opcodes.OP_PUSHDATA4:
            nSize = opcode
            if opcode == opcodes.OP_PUSHDATA1:
                nSize = ord(bytes[i])
                i += 1
            elif opcode == opcodes.OP_PUSHDATA2:
                (nSize,) = struct.unpack_from('<H', bytes, i)
                i += 2
            elif opcode == opcodes.OP_PUSHDATA4:
                (nSize,) = struct.unpack_from('<I', bytes, i)
                i += 4
            vch = bytes[i:i+nSize]
            i += nSize

        yield (opcode, vch, i)


def script_GetOpName(opcode):
    return (opcodes.whatis(opcode)).replace("OP_", "")


def decode_script(bytes):
    result = ''
    for (opcode, vch, i) in script_GetOp(bytes):
        if len(result) > 0: result += " "
        if opcode <= opcodes.OP_PUSHDATA4:
            result += "%d:"%(opcode,)
            result += short_hex(vch)
        else:
            result += script_GetOpName(opcode)
    return result


def match_decoded(decoded, to_match):
    if len(decoded) != len(to_match):
        return False;
    for i in range(len(decoded)):
        if to_match[i] == opcodes.OP_PUSHDATA4 and decoded[i][0] <= opcodes.OP_PUSHDATA4 and decoded[i][0]>0:
            continue  # Opcodes below OP_PUSHDATA4 all just push data onto stack, and are equivalent.
        if to_match[i] != decoded[i][0]:
            return False
    return True


def parse_sig(x_sig):
    return map(lambda x: None if x == NO_SIGNATURE else x, x_sig)

def safe_parse_pubkey(x):
    try:
        return xpubkey_to_pubkey(x)
    except:
        return x


def parse_scriptSig(d, bytes):
    try:
        decoded = [ x for x in script_GetOp(bytes) ]
    except Exception:
        # coinbase transactions raise an exception
        print_error("cannot find address in input script", bytes.encode('hex'))
        return

    match = [ opcodes.OP_PUSHDATA4 ]
    if match_decoded(decoded, match):
        item = decoded[0][1]
        if item[0] == chr(0):
            redeemScript = item.encode('hex')
            d['address'] = bitcoin.hash160_to_p2sh(bitcoin.hash_160(redeemScript.decode('hex')))
            d['type'] = 'p2wpkh-p2sh'
            d['redeemScript'] = redeemScript
            d['x_pubkeys'] = ["(witness)"]
            d['pubkeys'] = ["(witness)"]
            d['signatures'] = ['(witness)']
            d['num_sig'] = 1
        else:
            # payto_pubkey
            d['type'] = 'p2pk'
            d['address'] = "(pubkey)"
            d['signatures'] = [item.encode('hex')]
            d['num_sig'] = 1
            d['x_pubkeys'] = ["(pubkey)"]
            d['pubkeys'] = ["(pubkey)"]
        return

    # non-generated TxIn transactions push a signature
    # (seventy-something bytes) and then their public key
    # (65 bytes) onto the stack:
    match = [ opcodes.OP_PUSHDATA4, opcodes.OP_PUSHDATA4 ]
    if match_decoded(decoded, match):
        sig = decoded[0][1].encode('hex')
        x_pubkey = decoded[1][1].encode('hex')
        try:
            signatures = parse_sig([sig])
            pubkey, address = xpubkey_to_address(x_pubkey)
        except BaseException:
            print_error("cannot find address in input script", bytes.encode('hex'))
            return
        d['type'] = 'p2pkh'
        d['signatures'] = signatures
        d['x_pubkeys'] = [x_pubkey]
        d['num_sig'] = 1
        d['pubkeys'] = [pubkey]
        d['address'] = address
        return

    # p2sh transaction, m of n
    match = [ opcodes.OP_0 ] + [ opcodes.OP_PUSHDATA4 ] * (len(decoded) - 1)
    if not match_decoded(decoded, match):
        print_error("cannot find address in input script", bytes.encode('hex'))
        return
    x_sig = [x[1].encode('hex') for x in decoded[1:-1]]
    dec2 = [ x for x in script_GetOp(decoded[-1][1]) ]
    m = dec2[0][0] - opcodes.OP_1 + 1
    n = dec2[-2][0] - opcodes.OP_1 + 1
    op_m = opcodes.OP_1 + m - 1
    op_n = opcodes.OP_1 + n - 1
    match_multisig = [ op_m ] + [opcodes.OP_PUSHDATA4]*n + [ op_n, opcodes.OP_CHECKMULTISIG ]
    if not match_decoded(dec2, match_multisig):
        print_error("cannot find address in input script", bytes.encode('hex'))
        return
    x_pubkeys = map(lambda x: x[1].encode('hex'), dec2[1:-2])
    pubkeys = [safe_parse_pubkey(x) for x in x_pubkeys]
    redeemScript = multisig_script(pubkeys, m)
    # write result in d
    d['type'] = 'p2sh'
    d['num_sig'] = m
    d['signatures'] = parse_sig(x_sig)
    d['x_pubkeys'] = x_pubkeys
    d['pubkeys'] = pubkeys
    d['redeemScript'] = redeemScript
    d['address'] = hash160_to_p2sh(hash_160(redeemScript.decode('hex')))




def get_address_from_output_script(bytes):
    decoded = [ x for x in script_GetOp(bytes) ]

    # The Genesis Block, self-payments, and pay-by-IP-address payments look like:
    # 65 BYTES:... CHECKSIG
    match = [ opcodes.OP_PUSHDATA4, opcodes.OP_CHECKSIG ]
    if match_decoded(decoded, match):
        return TYPE_PUBKEY, decoded[0][1].encode('hex')

    # Pay-by-Bitcoin-address TxOuts look like:
    # DUP HASH160 20 BYTES:... EQUALVERIFY CHECKSIG
    match = [ opcodes.OP_DUP, opcodes.OP_HASH160, opcodes.OP_PUSHDATA4, opcodes.OP_EQUALVERIFY, opcodes.OP_CHECKSIG ]
    if match_decoded(decoded, match):
        return TYPE_ADDRESS, hash160_to_p2pkh(decoded[2][1])

    # p2sh
    match = [ opcodes.OP_HASH160, opcodes.OP_PUSHDATA4, opcodes.OP_EQUAL ]
    if match_decoded(decoded, match):
        return TYPE_ADDRESS, hash160_to_p2sh(decoded[1][1])

    return TYPE_SCRIPT, bytes





def parse_input(vds):
    d = {}
    prevout_hash = hash_encode(vds.read_bytes(32))
    prevout_n = vds.read_uint32()
    scriptSig = vds.read_bytes(vds.read_compact_size())
    sequence = vds.read_uint32()
    d['scriptSig'] = scriptSig.encode('hex')
    d['prevout_hash'] = prevout_hash
    d['prevout_n'] = prevout_n
    d['sequence'] = sequence
    if prevout_hash == '00'*32:
        d['type'] = 'coinbase'
    else:
        d['x_pubkeys'] = []
        d['pubkeys'] = []
        d['signatures'] = {}
        d['address'] = None
        d['type'] = 'unknown'
        d['num_sig'] = 0
        if scriptSig:
            parse_scriptSig(d, scriptSig)
    return d

def parse_witness(vds):
    n = vds.read_compact_size()
    for i in range(n):
        x = vds.read_bytes(vds.read_compact_size())

def parse_output(vds, i):
    d = {}
    d['value'] = vds.read_int64()
    scriptPubKey = vds.read_bytes(vds.read_compact_size())
    d['type'], d['address'] = get_address_from_output_script(scriptPubKey)
    d['scriptPubKey'] = scriptPubKey.encode('hex')
    d['prevout_n'] = i
    return d


def deserialize(raw):
    vds = BCDataStream()
    vds.write(raw.decode('hex'))
    d = {}
    start = vds.read_cursor
    d['version'] = vds.read_int32()
    n_vin = vds.read_compact_size()
    is_segwit = (n_vin == 0)
    if is_segwit:
        marker = vds.read_bytes(1)
        assert marker == chr(1)
        n_vin = vds.read_compact_size()
    d['inputs'] = list(parse_input(vds) for i in xrange(n_vin))
    n_vout = vds.read_compact_size()
    d['outputs'] = list(parse_output(vds,i) for i in xrange(n_vout))
    if is_segwit:
        d['witness'] = list(parse_witness(vds) for i in xrange(n_vin))
    d['lockTime'] = vds.read_uint32()
    return d


# pay & redeem scripts

def push_script(x):
    return op_push(len(x)/2) + x

def get_scriptPubKey(addr):
    addrtype, hash_160 = bc_address_to_hash_160(addr)
    if addrtype == bitcoin.ADDRTYPE_P2PKH:
        script = '76a9'                                      # op_dup, op_hash_160
        script += push_script(hash_160.encode('hex'))
        script += '88ac'                                     # op_equalverify, op_checksig
    elif addrtype == bitcoin.ADDRTYPE_P2SH:
        script = 'a9'                                        # op_hash_160
        script += push_script(hash_160.encode('hex'))
        script += '87'                                       # op_equal
    else:
        raise BaseException('unknown address type')
    return script

def segwit_script(pubkey):
    pubkey = safe_parse_pubkey(pubkey)
    pkh = hash_160(pubkey.decode('hex')).encode('hex')
    return '00' + push_script(pkh)

def multisig_script(public_keys, m):
    n = len(public_keys)
    assert n <= 15
    assert m <= n
    op_m = format(opcodes.OP_1 + m - 1, 'x')
    op_n = format(opcodes.OP_1 + n - 1, 'x')
    keylist = [op_push(len(k)/2) + k for k in public_keys]
    return op_m + ''.join(keylist) + op_n + 'ae'




class Transaction:

    def __str__(self):
        if self.raw is None:
            self.raw = self.serialize()
        return self.raw

    def __init__(self, raw):
        if raw is None:
            self.raw = None
        elif type(raw) in [str, unicode]:
            self.raw = raw.strip() if raw else None
        elif type(raw) is dict:
            self.raw = raw['hex']
        else:
            raise BaseException("cannot initialize transaction", raw)
        self._inputs = None
        self._outputs = None
        self.locktime = 0
        self.version = 1

    def update(self, raw):
        self.raw = raw
        self._inputs = None
        self.deserialize()

    def inputs(self):
        if self._inputs is None:
            self.deserialize()
        return self._inputs

    def outputs(self):
        if self._outputs is None:
            self.deserialize()
        return self._outputs

    @classmethod
    def get_sorted_pubkeys(self, txin):
        # sort pubkeys and x_pubkeys, using the order of pubkeys
        x_pubkeys = txin['x_pubkeys']
        pubkeys = txin.get('pubkeys')
        if pubkeys is None:
            pubkeys = [xpubkey_to_pubkey(x) for x in x_pubkeys]
            pubkeys, x_pubkeys = zip(*sorted(zip(pubkeys, x_pubkeys)))
            txin['pubkeys'] = pubkeys = list(pubkeys)
            txin['x_pubkeys'] = x_pubkeys = list(x_pubkeys)
        return pubkeys, x_pubkeys

    def update_signatures(self, raw):
        """Add new signatures to a transaction"""
        d = deserialize(raw)
        for i, txin in enumerate(self.inputs()):
            pubkeys, x_pubkeys = self.get_sorted_pubkeys(txin)
            sigs1 = txin.get('signatures')
            sigs2 = d['inputs'][i].get('signatures')
            for sig in sigs2:
                if sig in sigs1:
                    continue
                pre_hash = Hash(self.serialize_preimage(i).decode('hex'))
                # der to string
                order = ecdsa.ecdsa.generator_secp256k1.order()
                r, s = ecdsa.util.sigdecode_der(sig.decode('hex')[:-1], order)
                sig_string = ecdsa.util.sigencode_string(r, s, order)
                compressed = True
                for recid in range(4):
                    public_key = MyVerifyingKey.from_signature(sig_string, recid, pre_hash, curve = SECP256k1)
                    pubkey = point_to_ser(public_key.pubkey.point, compressed).encode('hex')
                    if pubkey in pubkeys:
                        public_key.verify_digest(sig_string, pre_hash, sigdecode = ecdsa.util.sigdecode_string)
                        j = pubkeys.index(pubkey)
                        print_error("adding sig", i, j, pubkey, sig)
                        self._inputs[i]['signatures'][j] = sig
                        self._inputs[i]['x_pubkeys'][j] = pubkey
                        break
        # redo raw
        self.raw = self.serialize()


    def deserialize(self):
        if self.raw is None:
            return
            #self.raw = self.serialize()
        if self._inputs is not None:
            return
        d = deserialize(self.raw)
        self._inputs = d['inputs']
        self._outputs = [(x['type'], x['address'], x['value']) for x in d['outputs']]
        self.locktime = d['lockTime']
        self.version = d['version']
        return d

    @classmethod
    def from_io(klass, inputs, outputs, locktime=0):
        self = klass(None)
        self._inputs = inputs
        self._outputs = outputs
        self.locktime = locktime
        return self

    @classmethod
    def pay_script(self, output_type, addr):
        if output_type == TYPE_SCRIPT:
            return addr.encode('hex')
        elif output_type == TYPE_ADDRESS:
            return get_scriptPubKey(addr)
        else:
            raise TypeError('Unknown output type')
        return script

    @classmethod
    def get_siglist(self, txin, estimate_size=False):
        # if we have enough signatures, we use the actual pubkeys
        # otherwise, use extended pubkeys (with bip32 derivation)
        num_sig = txin.get('num_sig', 1)
        if estimate_size:
            # we assume that signature will be 0x48 bytes long
            pk_list = [ "00" * 0x21 ] * num_sig
            sig_list = [ "00" * 0x48 ] * num_sig
        else:
            pubkeys, x_pubkeys = self.get_sorted_pubkeys(txin)
            x_signatures = txin['signatures']
            signatures = filter(None, x_signatures)
            is_complete = len(signatures) == num_sig
            if is_complete:
                pk_list = pubkeys
                sig_list = signatures
            else:
                pk_list = x_pubkeys
                sig_list = [sig if sig else NO_SIGNATURE for sig in x_signatures]
        return pk_list, sig_list

    @classmethod
    def serialize_witness(self, txin):
        pubkeys, sig_list = self.get_siglist(txin)
        n = len(pubkeys) + len(sig_list)
        return var_int(n) + ''.join(push_script(x) for x in sig_list) + ''.join(push_script(x) for x in pubkeys)

    @classmethod
    def is_segwit_input(self, txin):
        return txin['type'] in ['p2wpkh-p2sh']

    @classmethod
    def input_script(self, txin, estimate_size=False):
        _type = txin['type']
        if _type == 'coinbase':
            return txin['scriptSig']
        pubkeys, sig_list = self.get_siglist(txin, estimate_size)
        script = ''.join(push_script(x) for x in sig_list)
        if _type == 'p2pk':
            pass
        elif _type == 'p2sh':
            # put op_0 before script
            script = '00' + script
            redeem_script = multisig_script(pubkeys, txin['num_sig'])
            script += push_script(redeem_script)
        elif _type == 'p2pkh':
            script += push_script(pubkeys[0])
        elif _type == 'p2wpkh-p2sh':
            redeem_script = txin.get('redeemScript') or segwit_script(pubkeys[0])
            return push_script(redeem_script)
        elif _type == 'address':
            script += push_script(pubkeys[0])
        elif _type == 'unknown':
            return txin['scriptSig']
        return script

    @classmethod
    def get_preimage_script(self, txin):
        # only for non-segwit
        if txin['type'] == 'p2pkh':
            return get_scriptPubKey(txin['address'])
        elif txin['type'] == 'p2sh':
            pubkeys, x_pubkeys = self.get_sorted_pubkeys(txin)
            return multisig_script(pubkeys, txin['num_sig'])
        elif txin['type'] == 'p2wpkh-p2sh':
            pubkey = txin['pubkeys'][0]
            pkh = bitcoin.hash_160(pubkey.decode('hex')).encode('hex')
            return '76a9' + push_script(pkh) + '88ac'
        else:
            raise TypeError('Unknown txin type', _type)

    @classmethod
    def serialize_outpoint(self, txin):
        return txin['prevout_hash'].decode('hex')[::-1].encode('hex') + int_to_hex(txin['prevout_n'], 4)

    @classmethod
    def serialize_input(self, txin, script):
        # Prev hash and index
        s = self.serialize_outpoint(txin)
        # Script length, script, sequence
        s += var_int(len(script)/2)
        s += script
        s += int_to_hex(txin.get('sequence', 0xffffffff - 1), 4)
        return s

    def set_rbf(self, rbf):
        nSequence = 0xffffffff - (2 if rbf else 1)
        for txin in self.inputs():
            txin['sequence'] = nSequence

    def BIP_LI01_sort(self):
        # See https://github.com/kristovatlas/rfc/blob/master/bips/bip-li01.mediawiki
        self._inputs.sort(key = lambda i: (i['prevout_hash'], i['prevout_n']))
        self._outputs.sort(key = lambda o: (o[2], self.pay_script(o[0], o[1])))

    def serialize_output(self, output):
        output_type, addr, amount = output
        s = int_to_hex(amount, 8)
        script = self.pay_script(output_type, addr)
        s += var_int(len(script)/2)
        s += script
        return s

    def serialize_preimage(self, i):
        nVersion = int_to_hex(self.version, 4)
        nHashType = int_to_hex(1, 4)
        nLocktime = int_to_hex(self.locktime, 4)
        inputs = self.inputs()
        outputs = self.outputs()
        txin = inputs[i]
        if self.is_segwit_input(txin):
            hashPrevouts = Hash(''.join(self.serialize_outpoint(txin) for txin in inputs).decode('hex')).encode('hex')
            hashSequence = Hash(''.join(int_to_hex(txin.get('sequence', 0xffffffff - 1), 4) for txin in inputs).decode('hex')).encode('hex')
            hashOutputs = Hash(''.join(self.serialize_output(o) for o in outputs).decode('hex')).encode('hex')
            outpoint = self.serialize_outpoint(txin)
            preimage_script = self.get_preimage_script(txin)
            scriptCode = var_int(len(preimage_script)/2) + preimage_script
            amount = int_to_hex(txin['value'], 8)
            nSequence = int_to_hex(txin.get('sequence', 0xffffffff - 1), 4)
            preimage = nVersion + hashPrevouts + hashSequence + outpoint + scriptCode + amount + nSequence + hashOutputs + nLocktime + nHashType
        else:
            txins = var_int(len(inputs)) + ''.join(self.serialize_input(txin, self.get_preimage_script(txin) if i==k else '') for k, txin in enumerate(inputs))
            txouts = var_int(len(outputs)) + ''.join(self.serialize_output(o) for o in outputs)
            preimage = nVersion + txins + txouts + nLocktime + nHashType
        return preimage

    def is_segwit(self):
        return any(self.is_segwit_input(x) for x in self.inputs())

    def serialize(self, estimate_size=False, witness=True):
        nVersion = int_to_hex(self.version, 4)
        nLocktime = int_to_hex(self.locktime, 4)
        inputs = self.inputs()
        outputs = self.outputs()
        txins = var_int(len(inputs)) + ''.join(self.serialize_input(txin, self.input_script(txin, estimate_size)) for txin in inputs)
        txouts = var_int(len(outputs)) + ''.join(self.serialize_output(o) for o in outputs)
        if witness and self.is_segwit():
            marker = '00'
            flag = '01'
            witness = ''.join(self.serialize_witness(x) for x in inputs)
            return nVersion + marker + flag + txins + txouts + witness + nLocktime
        else:
            return nVersion + txins + txouts + nLocktime

    def hash(self):
        print "warning: deprecated tx.hash()"
        return self.txid()

    def txid(self):
        all_segwit = all(self.is_segwit_input(x) for x in self.inputs())
        if not all_segwit and not self.is_complete():
            return None
        ser = self.serialize(witness=False)
        return Hash(ser.decode('hex'))[::-1].encode('hex')

    def wtxid(self):
        ser = self.serialize(witness=True)
        return Hash(ser.decode('hex'))[::-1].encode('hex')

    def add_inputs(self, inputs):
        self._inputs.extend(inputs)
        self.raw = None

    def add_outputs(self, outputs):
        self._outputs.extend(outputs)
        self.raw = None

    def input_value(self):
        return sum(x['value'] for x in self.inputs())

    def output_value(self):
        return sum(val for tp, addr, val in self.outputs())

    def get_fee(self):
        return self.input_value() - self.output_value()

    def is_final(self):
        return not any([x.get('sequence', 0xffffffff - 1) < 0xffffffff - 1 for x in self.inputs()])

    @profiler
    def estimated_size(self):
        '''Return an estimated tx size in bytes.'''
        return len(self.serialize(True)) / 2 if not self.is_complete() or self.raw is None else len(self.raw) / 2 # ASCII hex string

    @classmethod
    def estimated_input_size(self, txin):
        '''Return an estimated of serialized input size in bytes.'''
        script = self.input_script(txin, True)
        return len(self.serialize_input(txin, script)) / 2

    def signature_count(self):
        r = 0
        s = 0
        for txin in self.inputs():
            if txin['type'] == 'coinbase':
                continue
            signatures = filter(None, txin.get('signatures',[]))
            s += len(signatures)
            r += txin.get('num_sig',-1)
        return s, r

    def is_complete(self):
        s, r = self.signature_count()
        return r == s

    def sign(self, keypairs):
        for i, txin in enumerate(self.inputs()):
            num = txin['num_sig']
            pubkeys, x_pubkeys = self.get_sorted_pubkeys(txin)
            for j, x_pubkey in enumerate(x_pubkeys):
                signatures = filter(None, txin['signatures'])
                if len(signatures) == num:
                    # txin is complete
                    break
                if x_pubkey in keypairs.keys():
                    print_error("adding signature for", x_pubkey)
                    sec = keypairs.get(x_pubkey)
                    pubkey = public_key_from_private_key(sec)
                    # add signature
                    pre_hash = Hash(self.serialize_preimage(i).decode('hex'))
                    pkey = regenerate_key(sec)
                    secexp = pkey.secret
                    private_key = bitcoin.MySigningKey.from_secret_exponent(secexp, curve = SECP256k1)
                    public_key = private_key.get_verifying_key()
                    sig = private_key.sign_digest_deterministic(pre_hash, hashfunc=hashlib.sha256, sigencode = ecdsa.util.sigencode_der)
                    assert public_key.verify_digest(sig, pre_hash, sigdecode = ecdsa.util.sigdecode_der)
                    txin['signatures'][j] = sig.encode('hex') + '01'
                    txin['x_pubkeys'][j] = pubkey
                    txin['pubkeys'][j] = pubkey # needed for fd keys
                    self._inputs[i] = txin
        print_error("is_complete", self.is_complete())
        self.raw = self.serialize()

    def get_outputs(self):
        """convert pubkeys to addresses"""
        o = []
        for type, x, v in self.outputs():
            if type == TYPE_ADDRESS:
                addr = x
            elif type == TYPE_PUBKEY:
                addr = bitcoin.public_key_to_p2pkh(x.decode('hex'))
            else:
                addr = 'SCRIPT ' + x.encode('hex')
            o.append((addr,v))      # consider using yield (addr, v)
        return o

    def get_output_addresses(self):
        return [addr for addr, val in self.get_outputs()]


    def has_address(self, addr):
        return (addr in self.get_output_addresses()) or (addr in (tx.get("address") for tx in self.inputs()))

    def as_dict(self):
        if self.raw is None:
            self.raw = self.serialize()
        self.deserialize()
        out = {
            'hex': self.raw,
            'complete': self.is_complete(),
            'final': self.is_final(),
        }
        return out


    def requires_fee(self, wallet):
        # see https://en.bitcoin.it/wiki/Transaction_fees
        #
        # size must be smaller than 1 kbyte for free tx
        size = len(self.serialize(-1))/2
        if size >= 10000:
            return True
        # all outputs must be 0.01 BTC or larger for free tx
        for addr, value in self.get_outputs():
            if value < 1000000:
                return True
        # priority must be large enough for free tx
        threshold = 57600000
        weight = 0
        for txin in self.inputs():
            height, conf, timestamp = wallet.get_tx_height(txin["prevout_hash"])
            weight += txin["value"] * conf
        priority = weight / size
        print_error(priority, threshold)

        return priority < threshold



def tx_from_str(txt):
    "json or raw hexadecimal"
    import json
    txt = txt.strip()
    try:
        txt.decode('hex')
        is_hex = True
    except:
        is_hex = False
    if is_hex:
        return txt
    tx_dict = json.loads(str(txt))
    assert "hex" in tx_dict.keys()
    return tx_dict["hex"]
