1 files changed, 0 insertions, 332 deletions
diff --git a/packages/taler-wallet-core/src/util/coinSelection.ts b/packages/taler-wallet-core/src/util/coinSelection.ts
deleted file mode 100644
index 500cee5d8..000000000
--- a/packages/taler-wallet-core/src/util/coinSelection.ts
+++ /dev/null
@@ -1,332 +0,0 @@
-/*
- This file is part of GNU Taler
- (C) 2021 Taler Systems S.A.
-
- GNU Taler is free software; you can redistribute it and/or modify it under the
- terms of the GNU General Public License as published by the Free Software
- Foundation; either version 3, or (at your option) any later version.
-
- GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
- WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License along with
- GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
- */
-
-/**
- * Selection of coins for payments.
- *
- * @author Florian Dold
- */
-
-/**
- * Imports.
- */
-import { AmountJson, Amounts } from "@gnu-taler/taler-util";
-import { strcmp, Logger } from "@gnu-taler/taler-util";
-
-const logger = new Logger("coinSelection.ts");
-
-/**
- * Result of selecting coins, contains the exchange, and selected
- * coins with their denomination.
- */
-export interface PayCoinSelection {
-  /**
-   * Amount requested by the merchant.
-   */
-  paymentAmount: AmountJson;
-
-  /**
-   * Public keys of the coins that were selected.
-   */
-  coinPubs: string[];
-
-  /**
-   * Amount that each coin contributes.
-   */
-  coinContributions: AmountJson[];
-
-  /**
-   * How much of the wire fees is the customer paying?
-   */
-  customerWireFees: AmountJson;
-
-  /**
-   * How much of the deposit fees is the customer paying?
-   */
-  customerDepositFees: AmountJson;
-}
-
-/**
- * Structure to describe a coin that is available to be
- * used in a payment.
- */
-export interface AvailableCoinInfo {
-  /**
-   * Public key of the coin.
-   */
-  coinPub: string;
-
-  /**
-   * Coin's denomination public key.
-   */
-  denomPub: string;
-
-  /**
-   * Amount still remaining (typically the full amount,
-   * as coins are always refreshed after use.)
-   */
-  availableAmount: AmountJson;
-
-  /**
-   * Deposit fee for the coin.
-   */
-  feeDeposit: AmountJson;
-
-  exchangeBaseUrl: string;
-}
-
-export type PreviousPayCoins = {
-  coinPub: string;
-  contribution: AmountJson;
-  feeDeposit: AmountJson;
-  exchangeBaseUrl: string;
-}[];
-
-export interface CoinCandidateSelection {
-  candidateCoins: AvailableCoinInfo[];
-  wireFeesPerExchange: Record<string, AmountJson>;
-}
-
-export interface SelectPayCoinRequest {
-  candidates: CoinCandidateSelection;
-  contractTermsAmount: AmountJson;
-  depositFeeLimit: AmountJson;
-  wireFeeLimit: AmountJson;
-  wireFeeAmortization: number;
-  prevPayCoins?: PreviousPayCoins;
-}
-
-interface CoinSelectionTally {
-  /**
-   * Amount that still needs to be paid.
-   * May increase during the computation when fees need to be covered.
-   */
-  amountPayRemaining: AmountJson;
-
-  /**
-   * Allowance given by the merchant towards wire fees
-   */
-  amountWireFeeLimitRemaining: AmountJson;
-
-  /**
-   * Allowance given by the merchant towards deposit fees
-   * (and wire fees after wire fee limit is exhausted)
-   */
-  amountDepositFeeLimitRemaining: AmountJson;
-
-  customerDepositFees: AmountJson;
-
-  customerWireFees: AmountJson;
-
-  wireFeeCoveredForExchange: Set<string>;
-}
-
-/**
- * Account for the fees of spending a coin.
- */
-function tallyFees(
-  tally: CoinSelectionTally,
-  wireFeesPerExchange: Record<string, AmountJson>,
-  wireFeeAmortization: number,
-  exchangeBaseUrl: string,
-  feeDeposit: AmountJson,
-): CoinSelectionTally {
-  const currency = tally.amountPayRemaining.currency;
-  let amountWireFeeLimitRemaining = tally.amountWireFeeLimitRemaining;
-  let amountDepositFeeLimitRemaining = tally.amountDepositFeeLimitRemaining;
-  let customerDepositFees = tally.customerDepositFees;
-  let customerWireFees = tally.customerWireFees;
-  let amountPayRemaining = tally.amountPayRemaining;
-  const wireFeeCoveredForExchange = new Set(tally.wireFeeCoveredForExchange);
-
-  if (!tally.wireFeeCoveredForExchange.has(exchangeBaseUrl)) {
-    const wf =
-      wireFeesPerExchange[exchangeBaseUrl] ?? Amounts.getZero(currency);
-    const wfForgiven = Amounts.min(amountWireFeeLimitRemaining, wf);
-    amountWireFeeLimitRemaining = Amounts.sub(
-      amountWireFeeLimitRemaining,
-      wfForgiven,
-    ).amount;
-    // The remaining, amortized amount needs to be paid by the
-    // wallet or covered by the deposit fee allowance.
-    let wfRemaining = Amounts.divide(
-      Amounts.sub(wf, wfForgiven).amount,
-      wireFeeAmortization,
-    );
-
-    // This is the amount forgiven via the deposit fee allowance.
-    const wfDepositForgiven = Amounts.min(
-      amountDepositFeeLimitRemaining,
-      wfRemaining,
-    );
-    amountDepositFeeLimitRemaining = Amounts.sub(
-      amountDepositFeeLimitRemaining,
-      wfDepositForgiven,
-    ).amount;
-
-    wfRemaining = Amounts.sub(wfRemaining, wfDepositForgiven).amount;
-    customerWireFees = Amounts.add(customerWireFees, wfRemaining).amount;
-    amountPayRemaining = Amounts.add(amountPayRemaining, wfRemaining).amount;
-
-    wireFeeCoveredForExchange.add(exchangeBaseUrl);
-  }
-
-  const dfForgiven = Amounts.min(feeDeposit, amountDepositFeeLimitRemaining);
-
-  amountDepositFeeLimitRemaining = Amounts.sub(
-    amountDepositFeeLimitRemaining,
-    dfForgiven,
-  ).amount;
-
-  // How much does the user spend on deposit fees for this coin?
-  const dfRemaining = Amounts.sub(feeDeposit, dfForgiven).amount;
-  customerDepositFees = Amounts.add(customerDepositFees, dfRemaining).amount;
-  amountPayRemaining = Amounts.add(amountPayRemaining, dfRemaining).amount;
-
-  return {
-    amountDepositFeeLimitRemaining,
-    amountPayRemaining,
-    amountWireFeeLimitRemaining,
-    customerDepositFees,
-    customerWireFees,
-    wireFeeCoveredForExchange,
-  };
-}
-
-/**
- * Given a list of candidate coins, select coins to spend under the merchant's
- * constraints.
- *
- * The prevPayCoins can be specified to "repair" a coin selection
- * by adding additional coins, after a broken (e.g. double-spent) coin
- * has been removed from the selection.
- *
- * This function is only exported for the sake of unit tests.
- */
-export function selectPayCoins(
-  req: SelectPayCoinRequest,
-): PayCoinSelection | undefined {
-  const {
-    candidates,
-    contractTermsAmount,
-    depositFeeLimit,
-    wireFeeLimit,
-    wireFeeAmortization,
-  } = req;
-
-  if (candidates.candidateCoins.length === 0) {
-    return undefined;
-  }
-  const coinPubs: string[] = [];
-  const coinContributions: AmountJson[] = [];
-  const currency = contractTermsAmount.currency;
-
-  let tally: CoinSelectionTally = {
-    amountPayRemaining: contractTermsAmount,
-    amountWireFeeLimitRemaining: wireFeeLimit,
-    amountDepositFeeLimitRemaining: depositFeeLimit,
-    customerDepositFees: Amounts.getZero(currency),
-    customerWireFees: Amounts.getZero(currency),
-    wireFeeCoveredForExchange: new Set(),
-  };
-
-  const prevPayCoins = req.prevPayCoins ?? [];
-
-  // Look at existing pay coin selection and tally up
-  for (const prev of prevPayCoins) {
-    tally = tallyFees(
-      tally,
-      candidates.wireFeesPerExchange,
-      wireFeeAmortization,
-      prev.exchangeBaseUrl,
-      prev.feeDeposit,
-    );
-    tally.amountPayRemaining = Amounts.sub(
-      tally.amountPayRemaining,
-      prev.contribution,
-    ).amount;
-
-    coinPubs.push(prev.coinPub);
-    coinContributions.push(prev.contribution);
-  }
-
-  const prevCoinPubs = new Set(prevPayCoins.map((x) => x.coinPub));
-
-  // Sort by available amount (descending),  deposit fee (ascending) and
-  // denomPub (ascending) if deposit fee is the same
-  // (to guarantee deterministic results)
-  const candidateCoins = [...candidates.candidateCoins].sort(
-    (o1, o2) =>
-      -Amounts.cmp(o1.availableAmount, o2.availableAmount) ||
-      Amounts.cmp(o1.feeDeposit, o2.feeDeposit) ||
-      strcmp(o1.denomPub, o2.denomPub),
-  );
-
-  // FIXME:  Here, we should select coins in a smarter way.
-  // Instead of always spending the next-largest coin,
-  // we should try to find the smallest coin that covers the
-  // amount.
-
-  for (const aci of candidateCoins) {
-    // Don't use this coin if depositing it is more expensive than
-    // the amount it would give the merchant.
-    if (Amounts.cmp(aci.feeDeposit, aci.availableAmount) > 0) {
-      continue;
-    }
-
-    if (Amounts.isZero(tally.amountPayRemaining)) {
-      // We have spent enough!
-      break;
-    }
-
-    // The same coin can't contribute twice to the same payment,
-    // by a fundamental, intentional limitation of the protocol.
-    if (prevCoinPubs.has(aci.coinPub)) {
-      continue;
-    }
-
-    tally = tallyFees(
-      tally,
-      candidates.wireFeesPerExchange,
-      wireFeeAmortization,
-      aci.exchangeBaseUrl,
-      aci.feeDeposit,
-    );
-
-    let coinSpend = Amounts.max(
-      Amounts.min(tally.amountPayRemaining, aci.availableAmount),
-      aci.feeDeposit,
-    );
-
-    tally.amountPayRemaining = Amounts.sub(
-      tally.amountPayRemaining,
-      coinSpend,
-    ).amount;
-    coinPubs.push(aci.coinPub);
-    coinContributions.push(coinSpend);
-  }
-
-  if (Amounts.isZero(tally.amountPayRemaining)) {
-    return {
-      paymentAmount: contractTermsAmount,
-      coinContributions,
-      coinPubs,
-      customerDepositFees: tally.customerDepositFees,
-      customerWireFees: tally.customerWireFees,
-    };
-  }
-  return undefined;
-}