1290 lines
37 KiB
TypeScript
1290 lines
37 KiB
TypeScript
/*
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This file is part of GNU Taler
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(C) 2021 Taler Systems S.A.
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GNU Taler is free software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3, or (at your option) any later version.
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GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
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*/
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/**
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* Selection of coins for payments.
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*
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* @author Florian Dold
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*/
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/**
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* Imports.
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*/
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import { GlobalIDB } from "@gnu-taler/idb-bridge";
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import {
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AbsoluteTime,
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AgeCommitmentProof,
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AgeRestriction,
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AmountJson,
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Amounts,
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AmountString,
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CoinStatus,
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DenominationInfo,
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DenominationPubKey,
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DenomSelectionState,
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ForcedCoinSel,
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ForcedDenomSel,
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GetPlanForOperationRequest,
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GetPlanForOperationResponse,
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j2s,
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Logger,
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parsePaytoUri,
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PayCoinSelection,
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PayMerchantInsufficientBalanceDetails,
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strcmp,
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TransactionType,
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} from "@gnu-taler/taler-util";
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import {
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AllowedAuditorInfo,
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AllowedExchangeInfo,
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DenominationRecord,
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} from "../db.js";
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import { getExchangeDetails, isWithdrawableDenom } from "../index.js";
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import { InternalWalletState } from "../internal-wallet-state.js";
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import { getMerchantPaymentBalanceDetails } from "../operations/balance.js";
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import { checkDbInvariant, checkLogicInvariant } from "./invariants.js";
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const logger = new Logger("coinSelection.ts");
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/**
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* Structure to describe a coin that is available to be
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* used in a payment.
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*/
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export interface AvailableCoinInfo {
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/**
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* Public key of the coin.
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*/
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coinPub: string;
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/**
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* Coin's denomination public key.
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*
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* FIXME: We should only need the denomPubHash here, if at all.
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*/
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denomPub: DenominationPubKey;
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/**
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* Full value of the coin.
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*/
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value: AmountJson;
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/**
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* Amount still remaining (typically the full amount,
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* as coins are always refreshed after use.)
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*/
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availableAmount: AmountJson;
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/**
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* Deposit fee for the coin.
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*/
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feeDeposit: AmountJson;
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exchangeBaseUrl: string;
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maxAge: number;
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ageCommitmentProof?: AgeCommitmentProof;
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}
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export type PreviousPayCoins = {
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coinPub: string;
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contribution: AmountJson;
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feeDeposit: AmountJson;
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exchangeBaseUrl: string;
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}[];
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export interface CoinCandidateSelection {
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candidateCoins: AvailableCoinInfo[];
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wireFeesPerExchange: Record<string, AmountJson>;
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}
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export interface SelectPayCoinRequest {
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candidates: CoinCandidateSelection;
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contractTermsAmount: AmountJson;
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depositFeeLimit: AmountJson;
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wireFeeLimit: AmountJson;
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wireFeeAmortization: number;
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prevPayCoins?: PreviousPayCoins;
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requiredMinimumAge?: number;
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}
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export interface CoinSelectionTally {
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/**
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* Amount that still needs to be paid.
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* May increase during the computation when fees need to be covered.
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*/
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amountPayRemaining: AmountJson;
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/**
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* Allowance given by the merchant towards wire fees
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*/
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amountWireFeeLimitRemaining: AmountJson;
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/**
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* Allowance given by the merchant towards deposit fees
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* (and wire fees after wire fee limit is exhausted)
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*/
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amountDepositFeeLimitRemaining: AmountJson;
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customerDepositFees: AmountJson;
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customerWireFees: AmountJson;
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wireFeeCoveredForExchange: Set<string>;
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lastDepositFee: AmountJson;
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}
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/**
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* Account for the fees of spending a coin.
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*/
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function tallyFees(
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tally: Readonly<CoinSelectionTally>,
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wireFeesPerExchange: Record<string, AmountJson>,
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wireFeeAmortization: number,
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exchangeBaseUrl: string,
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feeDeposit: AmountJson,
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): CoinSelectionTally {
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const currency = tally.amountPayRemaining.currency;
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let amountWireFeeLimitRemaining = tally.amountWireFeeLimitRemaining;
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let amountDepositFeeLimitRemaining = tally.amountDepositFeeLimitRemaining;
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let customerDepositFees = tally.customerDepositFees;
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let customerWireFees = tally.customerWireFees;
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let amountPayRemaining = tally.amountPayRemaining;
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const wireFeeCoveredForExchange = new Set(tally.wireFeeCoveredForExchange);
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if (!tally.wireFeeCoveredForExchange.has(exchangeBaseUrl)) {
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const wf =
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wireFeesPerExchange[exchangeBaseUrl] ?? Amounts.zeroOfCurrency(currency);
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const wfForgiven = Amounts.min(amountWireFeeLimitRemaining, wf);
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amountWireFeeLimitRemaining = Amounts.sub(
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amountWireFeeLimitRemaining,
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wfForgiven,
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).amount;
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// The remaining, amortized amount needs to be paid by the
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// wallet or covered by the deposit fee allowance.
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let wfRemaining = Amounts.divide(
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Amounts.sub(wf, wfForgiven).amount,
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wireFeeAmortization,
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);
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// This is the amount forgiven via the deposit fee allowance.
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const wfDepositForgiven = Amounts.min(
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amountDepositFeeLimitRemaining,
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wfRemaining,
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);
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amountDepositFeeLimitRemaining = Amounts.sub(
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amountDepositFeeLimitRemaining,
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wfDepositForgiven,
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).amount;
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wfRemaining = Amounts.sub(wfRemaining, wfDepositForgiven).amount;
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customerWireFees = Amounts.add(customerWireFees, wfRemaining).amount;
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amountPayRemaining = Amounts.add(amountPayRemaining, wfRemaining).amount;
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wireFeeCoveredForExchange.add(exchangeBaseUrl);
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}
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const dfForgiven = Amounts.min(feeDeposit, amountDepositFeeLimitRemaining);
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amountDepositFeeLimitRemaining = Amounts.sub(
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amountDepositFeeLimitRemaining,
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dfForgiven,
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).amount;
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// How much does the user spend on deposit fees for this coin?
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const dfRemaining = Amounts.sub(feeDeposit, dfForgiven).amount;
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customerDepositFees = Amounts.add(customerDepositFees, dfRemaining).amount;
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amountPayRemaining = Amounts.add(amountPayRemaining, dfRemaining).amount;
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return {
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amountDepositFeeLimitRemaining,
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amountPayRemaining,
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amountWireFeeLimitRemaining,
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customerDepositFees,
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customerWireFees,
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wireFeeCoveredForExchange,
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lastDepositFee: feeDeposit,
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};
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}
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export type SelectPayCoinsResult =
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| {
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type: "failure";
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insufficientBalanceDetails: PayMerchantInsufficientBalanceDetails;
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}
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| { type: "success"; coinSel: PayCoinSelection };
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/**
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* Given a list of candidate coins, select coins to spend under the merchant's
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* constraints.
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*
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* The prevPayCoins can be specified to "repair" a coin selection
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* by adding additional coins, after a broken (e.g. double-spent) coin
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* has been removed from the selection.
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*
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* This function is only exported for the sake of unit tests.
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*/
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export async function selectPayCoinsNew(
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ws: InternalWalletState,
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req: SelectPayCoinRequestNg,
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): Promise<SelectPayCoinsResult> {
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const {
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contractTermsAmount,
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depositFeeLimit,
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wireFeeLimit,
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wireFeeAmortization,
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} = req;
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const [candidateDenoms, wireFeesPerExchange] = await selectCandidates(
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ws,
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req,
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);
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const coinPubs: string[] = [];
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const coinContributions: AmountJson[] = [];
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const currency = contractTermsAmount.currency;
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let tally: CoinSelectionTally = {
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amountPayRemaining: contractTermsAmount,
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amountWireFeeLimitRemaining: wireFeeLimit,
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amountDepositFeeLimitRemaining: depositFeeLimit,
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customerDepositFees: Amounts.zeroOfCurrency(currency),
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customerWireFees: Amounts.zeroOfCurrency(currency),
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wireFeeCoveredForExchange: new Set(),
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lastDepositFee: Amounts.zeroOfCurrency(currency),
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};
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const prevPayCoins = req.prevPayCoins ?? [];
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// Look at existing pay coin selection and tally up
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for (const prev of prevPayCoins) {
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tally = tallyFees(
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tally,
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wireFeesPerExchange,
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wireFeeAmortization,
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prev.exchangeBaseUrl,
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prev.feeDeposit,
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);
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tally.amountPayRemaining = Amounts.sub(
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tally.amountPayRemaining,
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prev.contribution,
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).amount;
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coinPubs.push(prev.coinPub);
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coinContributions.push(prev.contribution);
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}
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let selectedDenom: SelResult | undefined;
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if (req.forcedSelection) {
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selectedDenom = selectForced(req, candidateDenoms);
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} else {
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// FIXME: Here, we should select coins in a smarter way.
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// Instead of always spending the next-largest coin,
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// we should try to find the smallest coin that covers the
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// amount.
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selectedDenom = selectGreedy(
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req,
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candidateDenoms,
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wireFeesPerExchange,
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tally,
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);
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}
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if (!selectedDenom) {
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const details = await getMerchantPaymentBalanceDetails(ws, {
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acceptedAuditors: req.auditors,
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acceptedExchanges: req.exchanges,
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acceptedWireMethods: [req.wireMethod],
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currency: Amounts.currencyOf(req.contractTermsAmount),
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minAge: req.requiredMinimumAge ?? 0,
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});
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let feeGapEstimate: AmountJson;
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if (
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Amounts.cmp(
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details.balanceMerchantDepositable,
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req.contractTermsAmount,
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) >= 0
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) {
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// FIXME: We can probably give a better estimate.
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feeGapEstimate = Amounts.add(
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tally.amountPayRemaining,
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tally.lastDepositFee,
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).amount;
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} else {
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feeGapEstimate = Amounts.zeroOfAmount(req.contractTermsAmount);
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}
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return {
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type: "failure",
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insufficientBalanceDetails: {
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amountRequested: Amounts.stringify(req.contractTermsAmount),
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balanceAgeAcceptable: Amounts.stringify(details.balanceAgeAcceptable),
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balanceAvailable: Amounts.stringify(details.balanceAvailable),
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balanceMaterial: Amounts.stringify(details.balanceMaterial),
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balanceMerchantAcceptable: Amounts.stringify(
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details.balanceMerchantAcceptable,
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),
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balanceMerchantDepositable: Amounts.stringify(
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details.balanceMerchantDepositable,
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),
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feeGapEstimate: Amounts.stringify(feeGapEstimate),
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},
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};
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}
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const finalSel = selectedDenom;
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logger.trace(`coin selection request ${j2s(req)}`);
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logger.trace(`selected coins (via denoms) for payment: ${j2s(finalSel)}`);
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await ws.db
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.mktx((x) => [x.coins, x.denominations])
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.runReadOnly(async (tx) => {
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for (const dph of Object.keys(finalSel)) {
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const selInfo = finalSel[dph];
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const numRequested = selInfo.contributions.length;
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const query = [
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selInfo.exchangeBaseUrl,
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selInfo.denomPubHash,
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selInfo.maxAge,
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CoinStatus.Fresh,
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];
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logger.info(`query: ${j2s(query)}`);
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const coins =
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await tx.coins.indexes.byExchangeDenomPubHashAndAgeAndStatus.getAll(
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query,
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numRequested,
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);
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if (coins.length != numRequested) {
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throw Error(
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`coin selection failed (not available anymore, got only ${coins.length}/${numRequested})`,
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);
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}
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coinPubs.push(...coins.map((x) => x.coinPub));
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coinContributions.push(...selInfo.contributions);
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}
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});
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return {
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type: "success",
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coinSel: {
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paymentAmount: Amounts.stringify(contractTermsAmount),
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coinContributions: coinContributions.map((x) => Amounts.stringify(x)),
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coinPubs,
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customerDepositFees: Amounts.stringify(tally.customerDepositFees),
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customerWireFees: Amounts.stringify(tally.customerWireFees),
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},
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};
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}
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function makeAvailabilityKey(
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exchangeBaseUrl: string,
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denomPubHash: string,
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maxAge: number,
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): string {
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return `${denomPubHash};${maxAge};${exchangeBaseUrl}`;
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}
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/**
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* Selection result.
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*/
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interface SelResult {
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/**
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* Map from an availability key
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* to an array of contributions.
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*/
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[avKey: string]: {
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exchangeBaseUrl: string;
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denomPubHash: string;
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maxAge: number;
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contributions: AmountJson[];
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};
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}
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function selectGreedy(
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req: SelectPayCoinRequestNg,
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candidateDenoms: AvailableDenom[],
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wireFeesPerExchange: Record<string, AmountJson>,
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tally: CoinSelectionTally,
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): SelResult | undefined {
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const { wireFeeAmortization } = req;
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const selectedDenom: SelResult = {};
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for (const denom of candidateDenoms) {
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const contributions: AmountJson[] = [];
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// Don't use this coin if depositing it is more expensive than
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// the amount it would give the merchant.
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if (Amounts.cmp(denom.feeDeposit, denom.value) > 0) {
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tally.lastDepositFee = Amounts.parseOrThrow(denom.feeDeposit);
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continue;
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}
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for (
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let i = 0;
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i < denom.numAvailable && Amounts.isNonZero(tally.amountPayRemaining);
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i++
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) {
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tally = tallyFees(
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tally,
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wireFeesPerExchange,
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wireFeeAmortization,
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denom.exchangeBaseUrl,
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Amounts.parseOrThrow(denom.feeDeposit),
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);
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const coinSpend = Amounts.max(
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Amounts.min(tally.amountPayRemaining, denom.value),
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denom.feeDeposit,
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);
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tally.amountPayRemaining = Amounts.sub(
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tally.amountPayRemaining,
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coinSpend,
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).amount;
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contributions.push(coinSpend);
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}
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if (contributions.length) {
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const avKey = makeAvailabilityKey(
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denom.exchangeBaseUrl,
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denom.denomPubHash,
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denom.maxAge,
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);
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let sd = selectedDenom[avKey];
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if (!sd) {
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sd = {
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contributions: [],
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denomPubHash: denom.denomPubHash,
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exchangeBaseUrl: denom.exchangeBaseUrl,
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maxAge: denom.maxAge,
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};
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}
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sd.contributions.push(...contributions);
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selectedDenom[avKey] = sd;
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}
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}
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return Amounts.isZero(tally.amountPayRemaining) ? selectedDenom : undefined;
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}
|
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|
|
function selectForced(
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req: SelectPayCoinRequestNg,
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candidateDenoms: AvailableDenom[],
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): SelResult | undefined {
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const selectedDenom: SelResult = {};
|
|
|
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const forcedSelection = req.forcedSelection;
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checkLogicInvariant(!!forcedSelection);
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|
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for (const forcedCoin of forcedSelection.coins) {
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let found = false;
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for (const aci of candidateDenoms) {
|
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if (aci.numAvailable <= 0) {
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continue;
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}
|
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if (Amounts.cmp(aci.value, forcedCoin.value) === 0) {
|
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aci.numAvailable--;
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const avKey = makeAvailabilityKey(
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aci.exchangeBaseUrl,
|
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aci.denomPubHash,
|
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aci.maxAge,
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);
|
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let sd = selectedDenom[avKey];
|
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if (!sd) {
|
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sd = {
|
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contributions: [],
|
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denomPubHash: aci.denomPubHash,
|
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exchangeBaseUrl: aci.exchangeBaseUrl,
|
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maxAge: aci.maxAge,
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};
|
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}
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sd.contributions.push(Amounts.parseOrThrow(forcedCoin.value));
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selectedDenom[avKey] = sd;
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found = true;
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break;
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}
|
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}
|
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if (!found) {
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throw Error("can't find coin for forced coin selection");
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}
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}
|
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return selectedDenom;
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}
|
|
|
|
export interface SelectPayCoinRequestNg {
|
|
exchanges: AllowedExchangeInfo[];
|
|
auditors: AllowedAuditorInfo[];
|
|
wireMethod: string;
|
|
contractTermsAmount: AmountJson;
|
|
depositFeeLimit: AmountJson;
|
|
wireFeeLimit: AmountJson;
|
|
wireFeeAmortization: number;
|
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prevPayCoins?: PreviousPayCoins;
|
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requiredMinimumAge?: number;
|
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forcedSelection?: ForcedCoinSel;
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}
|
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|
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export type AvailableDenom = DenominationInfo & {
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maxAge: number;
|
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numAvailable: number;
|
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};
|
|
|
|
async function selectCandidates(
|
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ws: InternalWalletState,
|
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req: SelectPayCoinRequestNg,
|
|
): Promise<[AvailableDenom[], Record<string, AmountJson>]> {
|
|
return await ws.db
|
|
.mktx((x) => [
|
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x.exchanges,
|
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x.exchangeDetails,
|
|
x.denominations,
|
|
x.coinAvailability,
|
|
])
|
|
.runReadOnly(async (tx) => {
|
|
// FIXME: Use the existing helper (from balance.ts) to
|
|
// get acceptable exchanges.
|
|
const denoms: AvailableDenom[] = [];
|
|
const exchanges = await tx.exchanges.iter().toArray();
|
|
const wfPerExchange: Record<string, AmountJson> = {};
|
|
for (const exchange of exchanges) {
|
|
const exchangeDetails = await getExchangeDetails(tx, exchange.baseUrl);
|
|
// 1.- exchange has same currency
|
|
if (exchangeDetails?.currency !== req.contractTermsAmount.currency) {
|
|
continue;
|
|
}
|
|
let wireMethodFee: string | undefined;
|
|
// 2.- exchange supports wire method
|
|
for (const acc of exchangeDetails.wireInfo.accounts) {
|
|
const pp = parsePaytoUri(acc.payto_uri);
|
|
checkLogicInvariant(!!pp);
|
|
if (pp.targetType === req.wireMethod) {
|
|
// also check that wire method is supported now
|
|
const wireFeeStr = exchangeDetails.wireInfo.feesForType[
|
|
req.wireMethod
|
|
]?.find((x) => {
|
|
return AbsoluteTime.isBetween(
|
|
AbsoluteTime.now(),
|
|
AbsoluteTime.fromProtocolTimestamp(x.startStamp),
|
|
AbsoluteTime.fromProtocolTimestamp(x.endStamp),
|
|
);
|
|
})?.wireFee;
|
|
if (wireFeeStr) {
|
|
wireMethodFee = wireFeeStr;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
if (!wireMethodFee) {
|
|
break;
|
|
}
|
|
wfPerExchange[exchange.baseUrl] = Amounts.parseOrThrow(wireMethodFee);
|
|
// 3.- exchange is trusted in the exchange list or auditor list
|
|
let accepted = false;
|
|
for (const allowedExchange of req.exchanges) {
|
|
if (allowedExchange.exchangePub === exchangeDetails.masterPublicKey) {
|
|
accepted = true;
|
|
break;
|
|
}
|
|
}
|
|
for (const allowedAuditor of req.auditors) {
|
|
for (const providedAuditor of exchangeDetails.auditors) {
|
|
if (allowedAuditor.auditorPub === providedAuditor.auditor_pub) {
|
|
accepted = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (!accepted) {
|
|
continue;
|
|
}
|
|
//4.- filter coins restricted by age
|
|
let ageLower = 0;
|
|
let ageUpper = AgeRestriction.AGE_UNRESTRICTED;
|
|
if (req.requiredMinimumAge) {
|
|
ageLower = req.requiredMinimumAge;
|
|
}
|
|
const myExchangeCoins =
|
|
await tx.coinAvailability.indexes.byExchangeAgeAvailability.getAll(
|
|
GlobalIDB.KeyRange.bound(
|
|
[exchangeDetails.exchangeBaseUrl, ageLower, 1],
|
|
[
|
|
exchangeDetails.exchangeBaseUrl,
|
|
ageUpper,
|
|
Number.MAX_SAFE_INTEGER,
|
|
],
|
|
),
|
|
);
|
|
//5.- save denoms with how many coins are available
|
|
// FIXME: Check that the individual denomination is audited!
|
|
// FIXME: Should we exclude denominations that are
|
|
// not spendable anymore?
|
|
for (const coinAvail of myExchangeCoins) {
|
|
const denom = await tx.denominations.get([
|
|
coinAvail.exchangeBaseUrl,
|
|
coinAvail.denomPubHash,
|
|
]);
|
|
checkDbInvariant(!!denom);
|
|
if (denom.isRevoked || !denom.isOffered) {
|
|
continue;
|
|
}
|
|
denoms.push({
|
|
...DenominationRecord.toDenomInfo(denom),
|
|
numAvailable: coinAvail.freshCoinCount ?? 0,
|
|
maxAge: coinAvail.maxAge,
|
|
});
|
|
}
|
|
}
|
|
// Sort by available amount (descending), deposit fee (ascending) and
|
|
// denomPub (ascending) if deposit fee is the same
|
|
// (to guarantee deterministic results)
|
|
denoms.sort(
|
|
(o1, o2) =>
|
|
-Amounts.cmp(o1.value, o2.value) ||
|
|
Amounts.cmp(o1.feeDeposit, o2.feeDeposit) ||
|
|
strcmp(o1.denomPubHash, o2.denomPubHash),
|
|
);
|
|
return [denoms, wfPerExchange];
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Get a list of denominations (with repetitions possible)
|
|
* whose total value is as close as possible to the available
|
|
* amount, but never larger.
|
|
*/
|
|
export function selectWithdrawalDenominations(
|
|
amountAvailable: AmountJson,
|
|
denoms: DenominationRecord[],
|
|
denomselAllowLate: boolean = false,
|
|
): DenomSelectionState {
|
|
let remaining = Amounts.copy(amountAvailable);
|
|
|
|
const selectedDenoms: {
|
|
count: number;
|
|
denomPubHash: string;
|
|
}[] = [];
|
|
|
|
let totalCoinValue = Amounts.zeroOfCurrency(amountAvailable.currency);
|
|
let totalWithdrawCost = Amounts.zeroOfCurrency(amountAvailable.currency);
|
|
|
|
denoms = denoms.filter((d) => isWithdrawableDenom(d, denomselAllowLate));
|
|
denoms.sort((d1, d2) =>
|
|
Amounts.cmp(
|
|
DenominationRecord.getValue(d2),
|
|
DenominationRecord.getValue(d1),
|
|
),
|
|
);
|
|
|
|
for (const d of denoms) {
|
|
const cost = Amounts.add(
|
|
DenominationRecord.getValue(d),
|
|
d.fees.feeWithdraw,
|
|
).amount;
|
|
const res = Amounts.divmod(remaining, cost);
|
|
const count = res.quotient;
|
|
remaining = Amounts.sub(remaining, Amounts.mult(cost, count).amount).amount;
|
|
if (count > 0) {
|
|
totalCoinValue = Amounts.add(
|
|
totalCoinValue,
|
|
Amounts.mult(DenominationRecord.getValue(d), count).amount,
|
|
).amount;
|
|
totalWithdrawCost = Amounts.add(
|
|
totalWithdrawCost,
|
|
Amounts.mult(cost, count).amount,
|
|
).amount;
|
|
selectedDenoms.push({
|
|
count,
|
|
denomPubHash: d.denomPubHash,
|
|
});
|
|
}
|
|
|
|
if (Amounts.isZero(remaining)) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (logger.shouldLogTrace()) {
|
|
logger.trace(
|
|
`selected withdrawal denoms for ${Amounts.stringify(totalCoinValue)}`,
|
|
);
|
|
for (const sd of selectedDenoms) {
|
|
logger.trace(`denom_pub_hash=${sd.denomPubHash}, count=${sd.count}`);
|
|
}
|
|
logger.trace("(end of withdrawal denom list)");
|
|
}
|
|
|
|
return {
|
|
selectedDenoms,
|
|
totalCoinValue: Amounts.stringify(totalCoinValue),
|
|
totalWithdrawCost: Amounts.stringify(totalWithdrawCost),
|
|
};
|
|
}
|
|
|
|
export function selectForcedWithdrawalDenominations(
|
|
amountAvailable: AmountJson,
|
|
denoms: DenominationRecord[],
|
|
forcedDenomSel: ForcedDenomSel,
|
|
denomselAllowLate: boolean,
|
|
): DenomSelectionState {
|
|
const selectedDenoms: {
|
|
count: number;
|
|
denomPubHash: string;
|
|
}[] = [];
|
|
|
|
let totalCoinValue = Amounts.zeroOfCurrency(amountAvailable.currency);
|
|
let totalWithdrawCost = Amounts.zeroOfCurrency(amountAvailable.currency);
|
|
|
|
denoms = denoms.filter((d) => isWithdrawableDenom(d, denomselAllowLate));
|
|
denoms.sort((d1, d2) =>
|
|
Amounts.cmp(
|
|
DenominationRecord.getValue(d2),
|
|
DenominationRecord.getValue(d1),
|
|
),
|
|
);
|
|
|
|
for (const fds of forcedDenomSel.denoms) {
|
|
const count = fds.count;
|
|
const denom = denoms.find((x) => {
|
|
return Amounts.cmp(DenominationRecord.getValue(x), fds.value) == 0;
|
|
});
|
|
if (!denom) {
|
|
throw Error(
|
|
`unable to find denom for forced selection (value ${fds.value})`,
|
|
);
|
|
}
|
|
const cost = Amounts.add(
|
|
DenominationRecord.getValue(denom),
|
|
denom.fees.feeWithdraw,
|
|
).amount;
|
|
totalCoinValue = Amounts.add(
|
|
totalCoinValue,
|
|
Amounts.mult(DenominationRecord.getValue(denom), count).amount,
|
|
).amount;
|
|
totalWithdrawCost = Amounts.add(
|
|
totalWithdrawCost,
|
|
Amounts.mult(cost, count).amount,
|
|
).amount;
|
|
selectedDenoms.push({
|
|
count,
|
|
denomPubHash: denom.denomPubHash,
|
|
});
|
|
}
|
|
|
|
return {
|
|
selectedDenoms,
|
|
totalCoinValue: Amounts.stringify(totalCoinValue),
|
|
totalWithdrawCost: Amounts.stringify(totalWithdrawCost),
|
|
};
|
|
}
|
|
|
|
/**
|
|
* simulate a coin selection and return the amount
|
|
* that will effectively change the wallet balance and
|
|
* the raw amount of the operation
|
|
*
|
|
* @param ws
|
|
* @param br
|
|
* @returns
|
|
*/
|
|
export async function getPlanForOperation(
|
|
ws: InternalWalletState,
|
|
req: GetPlanForOperationRequest,
|
|
): Promise<GetPlanForOperationResponse> {
|
|
const amount = Amounts.parseOrThrow(req.instructedAmount);
|
|
|
|
switch (req.type) {
|
|
case TransactionType.Withdrawal: {
|
|
const availableCoins = await getAvailableCoins(
|
|
ws,
|
|
"credit",
|
|
amount.currency,
|
|
false,
|
|
false,
|
|
undefined,
|
|
undefined,
|
|
undefined,
|
|
);
|
|
const usableCoins = selectCoinForOperation(
|
|
"credit",
|
|
amount,
|
|
req.mode === "effective" ? "net" : "gross",
|
|
availableCoins.denoms,
|
|
);
|
|
|
|
return getAmountsWithFee(
|
|
"credit",
|
|
usableCoins.totalValue,
|
|
usableCoins.totalContribution,
|
|
usableCoins,
|
|
);
|
|
}
|
|
case TransactionType.Deposit: {
|
|
const payto = parsePaytoUri(req.account)!;
|
|
const availableCoins = await getAvailableCoins(
|
|
ws,
|
|
"debit",
|
|
amount.currency,
|
|
true,
|
|
false,
|
|
undefined,
|
|
[payto.targetType],
|
|
undefined,
|
|
);
|
|
//FIXME: just doing for 1 exchange now
|
|
//assuming that the wallet has one exchange and all the coins available
|
|
//are from that exchange
|
|
|
|
const wireFee = Object.entries(availableCoins.wfPerExchange)[0][1][
|
|
payto.targetType
|
|
];
|
|
|
|
let usableCoins;
|
|
|
|
if (req.mode === "effective") {
|
|
usableCoins = selectCoinForOperation(
|
|
"debit",
|
|
amount,
|
|
"gross",
|
|
availableCoins.denoms,
|
|
);
|
|
|
|
usableCoins.totalContribution = Amounts.stringify(
|
|
Amounts.sub(usableCoins.totalContribution, wireFee).amount,
|
|
);
|
|
} else {
|
|
const adjustedAmount = Amounts.add(amount, wireFee).amount;
|
|
|
|
usableCoins = selectCoinForOperation(
|
|
"debit",
|
|
adjustedAmount,
|
|
// amount,
|
|
"net",
|
|
availableCoins.denoms,
|
|
);
|
|
|
|
usableCoins.totalContribution = Amounts.stringify(
|
|
Amounts.sub(usableCoins.totalContribution, wireFee).amount,
|
|
);
|
|
}
|
|
|
|
return getAmountsWithFee(
|
|
"debit",
|
|
usableCoins.totalValue,
|
|
usableCoins.totalContribution,
|
|
usableCoins,
|
|
);
|
|
}
|
|
default: {
|
|
throw Error("operation not supported");
|
|
}
|
|
}
|
|
}
|
|
|
|
function getAmountsWithFee(
|
|
op: "debit" | "credit",
|
|
value: AmountString,
|
|
contribution: AmountString,
|
|
details: any,
|
|
): GetPlanForOperationResponse {
|
|
return {
|
|
rawAmount: op === "credit" ? value : contribution,
|
|
effectiveAmount: op === "credit" ? contribution : value,
|
|
details,
|
|
};
|
|
}
|
|
|
|
/**
|
|
*
|
|
* @param op defined which fee are we taking into consideration: deposits or withdraw
|
|
* @param limit the total amount limit of the operation
|
|
* @param mode if the total amount is includes the fees or just the contribution
|
|
* @param denoms list of available denomination for the operation
|
|
* @returns
|
|
*/
|
|
function selectCoinForOperation(
|
|
op: "debit" | "credit",
|
|
limit: AmountJson,
|
|
mode: "net" | "gross",
|
|
denoms: AvailableDenom[],
|
|
): SelectedCoins {
|
|
const result: SelectedCoins = {
|
|
totalValue: Amounts.stringify(Amounts.zeroOfCurrency(limit.currency)),
|
|
totalWithdrawalFee: Amounts.stringify(
|
|
Amounts.zeroOfCurrency(limit.currency),
|
|
),
|
|
totalDepositFee: Amounts.stringify(Amounts.zeroOfCurrency(limit.currency)),
|
|
totalContribution: Amounts.stringify(
|
|
Amounts.zeroOfCurrency(limit.currency),
|
|
),
|
|
coins: [],
|
|
};
|
|
if (!denoms.length) return result;
|
|
/**
|
|
* We can make this faster. We should prevent sorting and
|
|
* keep the information ready for multiple calls since this
|
|
* function is expected to work on embedded devices and
|
|
* create a response on key press
|
|
*/
|
|
|
|
//rank coins
|
|
denoms.sort(
|
|
op === "credit"
|
|
? denomsByDescendingWithdrawContribution
|
|
: denomsByDescendingDepositContribution,
|
|
);
|
|
|
|
//take coins in order until amount
|
|
let selectedCoinsAreEnough = false;
|
|
let denomIdx = 0;
|
|
iterateDenoms: while (denomIdx < denoms.length) {
|
|
const cur = denoms[denomIdx];
|
|
// for (const cur of denoms) {
|
|
let total = op === "credit" ? Number.MAX_SAFE_INTEGER : cur.numAvailable;
|
|
const opFee = op === "credit" ? cur.feeWithdraw : cur.feeDeposit;
|
|
const contribution = Amounts.sub(cur.value, opFee).amount;
|
|
|
|
if (Amounts.isZero(contribution)) {
|
|
// 0 contribution denoms should be the last
|
|
break iterateDenoms;
|
|
}
|
|
iterateCoins: while (total > 0) {
|
|
const nextValue = Amounts.add(result.totalValue, cur.value).amount;
|
|
|
|
const nextContribution = Amounts.add(
|
|
result.totalContribution,
|
|
contribution,
|
|
).amount;
|
|
|
|
const progress = mode === "gross" ? nextValue : nextContribution;
|
|
|
|
if (Amounts.cmp(progress, limit) === 1) {
|
|
//the current coin is more than we need, try next denom
|
|
break iterateCoins;
|
|
}
|
|
|
|
result.totalValue = Amounts.stringify(nextValue);
|
|
result.totalContribution = Amounts.stringify(nextContribution);
|
|
|
|
result.totalDepositFee = Amounts.stringify(
|
|
Amounts.add(result.totalDepositFee, cur.feeDeposit).amount,
|
|
);
|
|
|
|
result.totalWithdrawalFee = Amounts.stringify(
|
|
Amounts.add(result.totalWithdrawalFee, cur.feeWithdraw).amount,
|
|
);
|
|
|
|
result.coins.push(cur.denomPubHash);
|
|
|
|
if (Amounts.cmp(progress, limit) === 0) {
|
|
selectedCoinsAreEnough = true;
|
|
// we have just enough coins, complete
|
|
break iterateDenoms;
|
|
}
|
|
|
|
//go next coin
|
|
total--;
|
|
}
|
|
//go next denom
|
|
denomIdx++;
|
|
}
|
|
|
|
if (selectedCoinsAreEnough) {
|
|
// we made it
|
|
return result;
|
|
}
|
|
if (op === "credit") {
|
|
//doing withdraw there is no way to cover the gap
|
|
return result;
|
|
}
|
|
//tried all the coins but there is a gap
|
|
//doing deposit we can try refreshing coins
|
|
|
|
const total = mode === "gross" ? result.totalValue : result.totalContribution;
|
|
const gap = Amounts.sub(limit, total).amount;
|
|
|
|
//about recursive calls
|
|
//the only way to get here is by doing a deposit (that will do a refresh)
|
|
//and now we are calculating fee for credit (which does not need to calculate refresh)
|
|
|
|
let refreshIdx = 0;
|
|
let choice: RefreshChoice | undefined = undefined;
|
|
refreshIteration: while (refreshIdx < denoms.length) {
|
|
const d = denoms[refreshIdx];
|
|
const denomContribution =
|
|
mode === "gross"
|
|
? Amounts.sub(d.value, d.feeRefresh).amount
|
|
: Amounts.sub(d.value, d.feeDeposit, d.feeRefresh).amount;
|
|
|
|
const changeAfterDeposit = Amounts.sub(denomContribution, gap).amount;
|
|
if (Amounts.isZero(changeAfterDeposit)) {
|
|
//the rest of the coins are very small
|
|
break refreshIteration;
|
|
}
|
|
|
|
const changeCost = selectCoinForOperation(
|
|
"credit",
|
|
changeAfterDeposit,
|
|
mode,
|
|
denoms,
|
|
);
|
|
const totalFee = Amounts.add(
|
|
d.feeDeposit,
|
|
d.feeRefresh,
|
|
changeCost.totalWithdrawalFee,
|
|
).amount;
|
|
|
|
if (!choice || Amounts.cmp(totalFee, choice.totalFee) === -1) {
|
|
//found cheaper change
|
|
choice = {
|
|
gap: Amounts.stringify(gap),
|
|
totalFee: Amounts.stringify(totalFee),
|
|
selected: d.denomPubHash,
|
|
totalValue: d.value,
|
|
totalRefreshFee: Amounts.stringify(d.feeRefresh),
|
|
totalDepositFee: d.feeDeposit,
|
|
totalChangeValue: Amounts.stringify(changeCost.totalValue),
|
|
totalChangeContribution: Amounts.stringify(
|
|
changeCost.totalContribution,
|
|
),
|
|
totalChangeWithdrawalFee: Amounts.stringify(
|
|
changeCost.totalWithdrawalFee,
|
|
),
|
|
change: changeCost.coins,
|
|
};
|
|
}
|
|
refreshIdx++;
|
|
}
|
|
if (choice) {
|
|
if (mode === "gross") {
|
|
result.totalValue = Amounts.stringify(
|
|
Amounts.add(result.totalValue, gap).amount,
|
|
);
|
|
result.totalContribution = Amounts.stringify(
|
|
Amounts.add(result.totalContribution, gap).amount,
|
|
);
|
|
result.totalContribution = Amounts.stringify(
|
|
Amounts.sub(result.totalContribution, choice.totalFee).amount,
|
|
);
|
|
} else {
|
|
result.totalContribution = Amounts.stringify(
|
|
Amounts.add(result.totalContribution, gap).amount,
|
|
);
|
|
result.totalValue = Amounts.stringify(
|
|
Amounts.add(result.totalValue, gap, choice.totalFee).amount,
|
|
);
|
|
}
|
|
}
|
|
|
|
// console.log("gap", Amounts.stringify(limit), Amounts.stringify(gap), choice);
|
|
result.refresh = choice;
|
|
return result;
|
|
}
|
|
|
|
function denomsByDescendingDepositContribution(
|
|
d1: AvailableDenom,
|
|
d2: AvailableDenom,
|
|
) {
|
|
const contrib1 = Amounts.sub(d1.value, d1.feeDeposit).amount;
|
|
const contrib2 = Amounts.sub(d2.value, d2.feeDeposit).amount;
|
|
return (
|
|
Amounts.cmp(contrib2, contrib1) || strcmp(d1.denomPubHash, d2.denomPubHash)
|
|
);
|
|
}
|
|
function denomsByDescendingWithdrawContribution(
|
|
d1: AvailableDenom,
|
|
d2: AvailableDenom,
|
|
) {
|
|
const contrib1 = Amounts.sub(d1.value, d1.feeWithdraw).amount;
|
|
const contrib2 = Amounts.sub(d2.value, d2.feeWithdraw).amount;
|
|
return (
|
|
Amounts.cmp(contrib2, contrib1) || strcmp(d1.denomPubHash, d2.denomPubHash)
|
|
);
|
|
}
|
|
|
|
interface RefreshChoice {
|
|
gap: AmountString;
|
|
totalFee: AmountString;
|
|
selected: string;
|
|
|
|
totalValue: AmountString;
|
|
totalDepositFee: AmountString;
|
|
totalRefreshFee: AmountString;
|
|
totalChangeValue: AmountString;
|
|
totalChangeContribution: AmountString;
|
|
totalChangeWithdrawalFee: AmountString;
|
|
change: string[];
|
|
}
|
|
|
|
interface SelectedCoins {
|
|
totalValue: AmountString;
|
|
totalContribution: AmountString;
|
|
totalWithdrawalFee: AmountString;
|
|
totalDepositFee: AmountString;
|
|
coins: string[];
|
|
refresh?: RefreshChoice;
|
|
}
|
|
|
|
/**
|
|
* Get all the denoms that can be used for a operation that is limited
|
|
* by the following restrictions.
|
|
* This function is costly (by the database access) but with high chances
|
|
* of being cached
|
|
*/
|
|
async function getAvailableCoins(
|
|
ws: InternalWalletState,
|
|
op: "credit" | "debit",
|
|
currency: string,
|
|
shouldCalculateWireFee: boolean,
|
|
shouldCalculatePurseFee: boolean,
|
|
exchangeFilter: string[] | undefined,
|
|
wireMethodFilter: string[] | undefined,
|
|
ageRestrictedFilter: number | undefined,
|
|
) {
|
|
return await ws.db
|
|
.mktx((x) => [
|
|
x.exchanges,
|
|
x.exchangeDetails,
|
|
x.denominations,
|
|
x.coinAvailability,
|
|
])
|
|
.runReadOnly(async (tx) => {
|
|
const denoms: AvailableDenom[] = [];
|
|
const wfPerExchange: Record<string, Record<string, AmountJson>> = {};
|
|
const pfPerExchange: Record<string, AmountJson> = {};
|
|
|
|
const databaseExchanges = await tx.exchanges.iter().toArray();
|
|
const exchanges =
|
|
exchangeFilter === undefined
|
|
? databaseExchanges.map((e) => e.baseUrl)
|
|
: exchangeFilter;
|
|
|
|
for (const exchangeBaseUrl of exchanges) {
|
|
const exchangeDetails = await getExchangeDetails(tx, exchangeBaseUrl);
|
|
// 1.- exchange has same currency
|
|
if (exchangeDetails?.currency !== currency) {
|
|
continue;
|
|
}
|
|
|
|
const wireMethodFee: Record<string, AmountJson> = {};
|
|
// 2.- exchange supports wire method
|
|
if (shouldCalculateWireFee) {
|
|
for (const acc of exchangeDetails.wireInfo.accounts) {
|
|
const pp = parsePaytoUri(acc.payto_uri);
|
|
checkLogicInvariant(!!pp);
|
|
// also check that wire method is supported now
|
|
if (wireMethodFilter !== undefined) {
|
|
if (wireMethodFilter.indexOf(pp.targetType) === -1) {
|
|
continue;
|
|
}
|
|
}
|
|
const wireFeeStr = exchangeDetails.wireInfo.feesForType[
|
|
pp.targetType
|
|
]?.find((x) => {
|
|
return AbsoluteTime.isBetween(
|
|
AbsoluteTime.now(),
|
|
AbsoluteTime.fromProtocolTimestamp(x.startStamp),
|
|
AbsoluteTime.fromProtocolTimestamp(x.endStamp),
|
|
);
|
|
})?.wireFee;
|
|
|
|
if (wireFeeStr) {
|
|
wireMethodFee[pp.targetType] = Amounts.parseOrThrow(wireFeeStr);
|
|
}
|
|
break;
|
|
}
|
|
if (Object.keys(wireMethodFee).length === 0) {
|
|
throw Error(
|
|
`exchange ${exchangeBaseUrl} doesn't have wire fee defined for this period`,
|
|
);
|
|
}
|
|
}
|
|
wfPerExchange[exchangeBaseUrl] = wireMethodFee;
|
|
|
|
// 3.- exchange supports wire method
|
|
if (shouldCalculatePurseFee) {
|
|
const purseFeeFound = exchangeDetails.globalFees.find((x) => {
|
|
return AbsoluteTime.isBetween(
|
|
AbsoluteTime.now(),
|
|
AbsoluteTime.fromProtocolTimestamp(x.startDate),
|
|
AbsoluteTime.fromProtocolTimestamp(x.endDate),
|
|
);
|
|
})?.purseFee;
|
|
if (!purseFeeFound) {
|
|
throw Error(
|
|
`exchange ${exchangeBaseUrl} doesn't have purse fee defined for this period`,
|
|
);
|
|
}
|
|
const purseFee = Amounts.parseOrThrow(purseFeeFound);
|
|
pfPerExchange[exchangeBaseUrl] = purseFee;
|
|
}
|
|
|
|
//4.- filter coins restricted by age
|
|
if (op === "credit") {
|
|
const ds = await tx.denominations.indexes.byExchangeBaseUrl.getAll(
|
|
exchangeBaseUrl,
|
|
);
|
|
for (const denom of ds) {
|
|
denoms.push({
|
|
...DenominationRecord.toDenomInfo(denom),
|
|
numAvailable: Number.MAX_SAFE_INTEGER,
|
|
maxAge: AgeRestriction.AGE_UNRESTRICTED,
|
|
});
|
|
}
|
|
} else {
|
|
const ageLower = !ageRestrictedFilter ? 0 : ageRestrictedFilter;
|
|
const ageUpper = AgeRestriction.AGE_UNRESTRICTED;
|
|
|
|
const myExchangeCoins =
|
|
await tx.coinAvailability.indexes.byExchangeAgeAvailability.getAll(
|
|
GlobalIDB.KeyRange.bound(
|
|
[exchangeDetails.exchangeBaseUrl, ageLower, 1],
|
|
[
|
|
exchangeDetails.exchangeBaseUrl,
|
|
ageUpper,
|
|
Number.MAX_SAFE_INTEGER,
|
|
],
|
|
),
|
|
);
|
|
//5.- save denoms with how many coins are available
|
|
// FIXME: Check that the individual denomination is audited!
|
|
// FIXME: Should we exclude denominations that are
|
|
// not spendable anymore?
|
|
for (const coinAvail of myExchangeCoins) {
|
|
const denom = await tx.denominations.get([
|
|
coinAvail.exchangeBaseUrl,
|
|
coinAvail.denomPubHash,
|
|
]);
|
|
checkDbInvariant(!!denom);
|
|
if (denom.isRevoked || !denom.isOffered) {
|
|
continue;
|
|
}
|
|
denoms.push({
|
|
...DenominationRecord.toDenomInfo(denom),
|
|
numAvailable: coinAvail.freshCoinCount ?? 0,
|
|
maxAge: coinAvail.maxAge,
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
return {
|
|
denoms,
|
|
wfPerExchange,
|
|
pfPerExchange,
|
|
};
|
|
});
|
|
}
|