URI: 
       tmake function for determining who pays fee - electrum - Electrum Bitcoin wallet
  HTML git clone https://git.parazyd.org/electrum
   DIR Log
   DIR Files
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   DIR Submodules
       ---
   DIR commit eabe23f6b8b38d571e7f5c42f4b7e8091d275b7f
   DIR parent cd175f0949f105cb1ff3743867978c6583a93f3e
  HTML Author: Janus <ysangkok@gmail.com>
       Date:   Mon, 15 Oct 2018 18:36:13 +0200
       
       make function for determining who pays fee
       
       Diffstat:
         M electrum/lnchan.py                  |      15 +++++++++------
         M electrum/lnutil.py                  |      58 +++++++++++++++----------------
         M electrum/tests/test_lnutil.py       |      10 +++++-----
       
       3 files changed, 42 insertions(+), 41 deletions(-)
       ---
   DIR diff --git a/electrum/lnchan.py b/electrum/lnchan.py
       t@@ -18,7 +18,7 @@ from .lnutil import sign_and_get_sig_string
        from .lnutil import make_htlc_tx_with_open_channel, make_commitment, make_received_htlc, make_offered_htlc
        from .lnutil import HTLC_TIMEOUT_WEIGHT, HTLC_SUCCESS_WEIGHT
        from .lnutil import funding_output_script, LOCAL, REMOTE, HTLCOwner, make_closing_tx, make_outputs
       -from .lnutil import ScriptHtlc, SENT, RECEIVED, PaymentFailure
       +from .lnutil import ScriptHtlc, SENT, RECEIVED, PaymentFailure, calc_onchain_fees
        from .transaction import Transaction, TxOutput, construct_witness
        from .simple_config import SimpleConfig, FEERATE_FALLBACK_STATIC_FEE
        
       t@@ -656,8 +656,8 @@ class Channel(PrintError):
                    this_config.multisig_key.pubkey,
                    other_config.multisig_key.pubkey,
                    payment_pubkey,
       -            self.config[LOCAL].payment_basepoint.pubkey,
       -            self.config[REMOTE].payment_basepoint.pubkey,
       +            self.config[LOCAL if     self.constraints.is_initiator else REMOTE].payment_basepoint.pubkey,
       +            self.config[LOCAL if not self.constraints.is_initiator else REMOTE].payment_basepoint.pubkey,
                    other_revocation_pubkey,
                    derive_pubkey(this_config.delayed_basepoint.pubkey, this_point),
                    other_config.to_self_delay,
       t@@ -666,9 +666,12 @@ class Channel(PrintError):
                    local_msat,
                    remote_msat,
                    this_config.dust_limit_sat,
       -            self.pending_feerate(subject),
       -            subject == LOCAL,
       -            self.constraints.is_initiator,
       +            calc_onchain_fees(
       +                len(htlcs),
       +                self.pending_feerate(subject),
       +                subject == LOCAL,
       +                self.constraints.is_initiator,
       +            ),
                    htlcs=htlcs)
        
            def make_closing_tx(self, local_script: bytes, remote_script: bytes, fee_sat: Optional[int] = None) -> (bytes, int):
   DIR diff --git a/electrum/lnutil.py b/electrum/lnutil.py
       t@@ -1,7 +1,7 @@
        from enum import IntFlag, IntEnum
        import json
        from collections import namedtuple
       -from typing import NamedTuple, List, Tuple
       +from typing import NamedTuple, List, Tuple, Mapping
        import re
        
        from .util import bfh, bh2u, inv_dict
       t@@ -313,12 +313,10 @@ def make_htlc_tx_with_open_channel(chan, pcp, for_us, we_receive, commit, htlc):
            return htlc_tx
        
        def make_funding_input(local_funding_pubkey: bytes, remote_funding_pubkey: bytes,
       -        payment_basepoint: bytes, remote_payment_basepoint: bytes, we_are_initiator: bool,
       +        payment_basepoint: bytes, remote_payment_basepoint: bytes,
                funding_pos: int, funding_txid: bytes, funding_sat: int):
            pubkeys = sorted([bh2u(local_funding_pubkey), bh2u(remote_funding_pubkey)])
            payments = [payment_basepoint, remote_payment_basepoint]
       -    if not we_are_initiator:
       -        payments.reverse()
            # commitment tx input
            c_input = {
                'type': 'p2wsh',
       t@@ -332,11 +330,23 @@ def make_funding_input(local_funding_pubkey: bytes, remote_funding_pubkey: bytes
            }
            return c_input, payments
        
       -def make_outputs(fee_msat: int, we_pay_fee: bool, local_amount: int, remote_amount: int,
       +class HTLCOwner(IntFlag):
       +    LOCAL = 1
       +    REMOTE = -LOCAL
       +
       +    SENT = LOCAL
       +    RECEIVED = REMOTE
       +
       +SENT = HTLCOwner.SENT
       +RECEIVED = HTLCOwner.RECEIVED
       +LOCAL = HTLCOwner.LOCAL
       +REMOTE = HTLCOwner.REMOTE
       +
       +def make_outputs(fees_per_participant: Mapping[HTLCOwner, int], local_amount: int, remote_amount: int,
                local_tupl, remote_tupl, htlcs: List[ScriptHtlc], dust_limit_sat: int) -> Tuple[List[TxOutput], List[TxOutput]]:
       -    to_local_amt = local_amount - (fee_msat if we_pay_fee else 0)
       +    to_local_amt = local_amount - fees_per_participant[LOCAL]
            to_local = TxOutput(*local_tupl, to_local_amt // 1000)
       -    to_remote_amt = remote_amount - (fee_msat if not we_pay_fee else 0)
       +    to_remote_amt = remote_amount - fees_per_participant[REMOTE]
            to_remote = TxOutput(*remote_tupl, to_remote_amt // 1000)
            non_htlc_outputs = [to_local, to_remote]
            htlc_outputs = []
       t@@ -349,16 +359,22 @@ def make_outputs(fee_msat: int, we_pay_fee: bool, local_amount: int, remote_amou
            c_outputs_filtered = list(filter(lambda x: x.value >= dust_limit_sat, non_htlc_outputs + htlc_outputs))
            return htlc_outputs, c_outputs_filtered
        
       +def calc_onchain_fees(num_htlcs, feerate, for_us, we_are_initiator):
       +    we_pay_fee = for_us == we_are_initiator
       +    overall_weight = 500 + 172 * num_htlcs + 224
       +    fee = feerate * overall_weight
       +    fee = fee // 1000 * 1000
       +    return {LOCAL: fee if we_pay_fee else 0, REMOTE: fee if not we_pay_fee else 0}
        
        def make_commitment(ctn, local_funding_pubkey, remote_funding_pubkey,
                            remote_payment_pubkey, payment_basepoint,
                            remote_payment_basepoint, revocation_pubkey,
                            delayed_pubkey, to_self_delay, funding_txid,
                            funding_pos, funding_sat, local_amount, remote_amount,
       -                    dust_limit_sat, local_feerate, for_us, we_are_initiator,
       +                    dust_limit_sat, fees_per_participant,
                            htlcs):
            c_input, payments = make_funding_input(local_funding_pubkey, remote_funding_pubkey,
       -        payment_basepoint, remote_payment_basepoint, we_are_initiator, funding_pos,
       +        payment_basepoint, remote_payment_basepoint, funding_pos,
                funding_txid, funding_sat)
            obs = get_obscured_ctn(ctn, *payments)
            locktime = (0x20 << 24) + (obs & 0xffffff)
       t@@ -371,11 +387,8 @@ def make_commitment(ctn, local_funding_pubkey, remote_funding_pubkey,
            local_address = make_commitment_output_to_local_address(revocation_pubkey, to_self_delay, delayed_pubkey)
            remote_address = make_commitment_output_to_remote_address(remote_payment_pubkey)
            # TODO trim htlc outputs here while also considering 2nd stage htlc transactions
       -    fee = local_feerate * overall_weight(len(htlcs))
       -    fee = fee // 1000 * 1000
       -    we_pay_fee = for_us == we_are_initiator
        
       -    htlc_outputs, c_outputs_filtered = make_outputs(fee, we_pay_fee, local_amount, remote_amount,
       +    htlc_outputs, c_outputs_filtered = make_outputs(fees_per_participant, local_amount, remote_amount,
                (bitcoin.TYPE_ADDRESS, local_address), (bitcoin.TYPE_ADDRESS, remote_address), htlcs, dust_limit_sat)
        
            assert sum(x.value for x in c_outputs_filtered) <= funding_sat
       t@@ -453,9 +466,6 @@ def extract_ctn_from_tx_and_chan(tx, chan) -> int:
                                       funder_payment_basepoint=funder_conf.payment_basepoint.pubkey,
                                       fundee_payment_basepoint=fundee_conf.payment_basepoint.pubkey)
        
       -def overall_weight(num_htlc):
       -    return 500 + 172 * num_htlc + 224
       -
        def get_ecdh(priv: bytes, pub: bytes) -> bytes:
            pt = ECPubkey(pub) * string_to_number(priv)
            return sha256(pt.get_public_key_bytes())
       t@@ -511,23 +521,11 @@ def get_compressed_pubkey_from_bech32(bech32_pubkey: str) -> bytes:
            return bytes(data_8bits)
        
        
       -class HTLCOwner(IntFlag):
       -    LOCAL = 1
       -    REMOTE = -LOCAL
       -
       -    SENT = LOCAL
       -    RECEIVED = REMOTE
       -
       -SENT = HTLCOwner.SENT
       -RECEIVED = HTLCOwner.RECEIVED
       -LOCAL = HTLCOwner.LOCAL
       -REMOTE = HTLCOwner.REMOTE
       -
        def make_closing_tx(local_funding_pubkey: bytes, remote_funding_pubkey: bytes,
       -        payment_basepoint: bytes, remote_payment_basepoint: bytes, we_are_initiator: bool,
       +        payment_basepoint: bytes, remote_payment_basepoint: bytes,
                funding_txid: bytes, funding_pos: int, funding_sat: int, outputs: List[TxOutput]):
            c_input, payments = make_funding_input(local_funding_pubkey, remote_funding_pubkey,
       -        payment_basepoint, remote_payment_basepoint, we_are_initiator, funding_pos,
       +        payment_basepoint, remote_payment_basepoint, funding_pos,
                funding_txid, funding_sat)
            c_input['sequence'] = 0xFFFF_FFFF
            tx = Transaction.from_io([c_input], outputs, locktime=0, version=2)
   DIR diff --git a/electrum/tests/test_lnutil.py b/electrum/tests/test_lnutil.py
       t@@ -6,7 +6,7 @@ from electrum.lnutil import (RevocationStore, get_per_commitment_secret_from_see
                                     make_htlc_tx_inputs, secret_to_pubkey, derive_blinded_pubkey, derive_privkey,
                                     derive_pubkey, make_htlc_tx, extract_ctn_from_tx, UnableToDeriveSecret,
                                     get_compressed_pubkey_from_bech32, split_host_port, ConnStringFormatError,
       -                             ScriptHtlc, extract_nodeid)
       +                             ScriptHtlc, extract_nodeid, calc_onchain_fees)
        from electrum import lnchan
        from electrum.util import bh2u, bfh
        from electrum.transaction import Transaction
       t@@ -506,7 +506,7 @@ class TestLNUtil(unittest.TestCase):
                    local_revocation_pubkey, local_delayedpubkey, local_delay,
                    funding_tx_id, funding_output_index, funding_amount_satoshi,
                    to_local_msat, to_remote_msat, local_dust_limit_satoshi,
       -            local_feerate_per_kw, True, we_are_initiator=True, htlcs=htlcs)
       +            calc_onchain_fees(len(htlcs), local_feerate_per_kw, True, we_are_initiator=True), htlcs=htlcs)
                self.sign_and_insert_remote_sig(our_commit_tx, remote_funding_pubkey, remote_signature, local_funding_pubkey, local_funding_privkey)
                self.assertEqual(str(our_commit_tx), output_commit_tx)
        
       t@@ -584,7 +584,7 @@ class TestLNUtil(unittest.TestCase):
                    local_revocation_pubkey, local_delayedpubkey, local_delay,
                    funding_tx_id, funding_output_index, funding_amount_satoshi,
                    to_local_msat, to_remote_msat, local_dust_limit_satoshi,
       -            local_feerate_per_kw, True, we_are_initiator=True, htlcs=[])
       +            calc_onchain_fees(0, local_feerate_per_kw, True, we_are_initiator=True), htlcs=[])
                self.sign_and_insert_remote_sig(our_commit_tx, remote_funding_pubkey, remote_signature, local_funding_pubkey, local_funding_privkey)
        
                self.assertEqual(str(our_commit_tx), output_commit_tx)
       t@@ -603,7 +603,7 @@ class TestLNUtil(unittest.TestCase):
                    local_revocation_pubkey, local_delayedpubkey, local_delay,
                    funding_tx_id, funding_output_index, funding_amount_satoshi,
                    to_local_msat, to_remote_msat, local_dust_limit_satoshi,
       -            local_feerate_per_kw, True, we_are_initiator=True, htlcs=[])
       +            calc_onchain_fees(0, local_feerate_per_kw, True, we_are_initiator=True), htlcs=[])
                self.sign_and_insert_remote_sig(our_commit_tx, remote_funding_pubkey, remote_signature, local_funding_pubkey, local_funding_privkey)
        
                self.assertEqual(str(our_commit_tx), output_commit_tx)
       t@@ -661,7 +661,7 @@ class TestLNUtil(unittest.TestCase):
                    local_revocation_pubkey, local_delayedpubkey, local_delay,
                    funding_tx_id, funding_output_index, funding_amount_satoshi,
                    to_local_msat, to_remote_msat, local_dust_limit_satoshi,
       -            local_feerate_per_kw, True, we_are_initiator=True, htlcs=[])
       +            calc_onchain_fees(0, local_feerate_per_kw, True, we_are_initiator=True), htlcs=[])
                self.sign_and_insert_remote_sig(our_commit_tx, remote_funding_pubkey, remote_signature, local_funding_pubkey, local_funding_privkey)
                ref_commit_tx_str = '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'
                self.assertEqual(str(our_commit_tx), ref_commit_tx_str)