1 files changed, 58 insertions, 26 deletions

diff --git a/packages/taler-wallet-core/src/util/coinSelection.ts b/packages/taler-wallet-core/src/util/coinSelection.ts
index f6d8abcd4..c5a810c4f 100644
--- a/packages/taler-wallet-core/src/util/coinSelection.ts
+++ b/packages/taler-wallet-core/src/util/coinSelection.ts
@@ -46,6 +46,7 @@ import {
   PayCoinSelection,
   PayMerchantInsufficientBalanceDetails,
   strcmp,
+  TransactionAmountMode,
   TransactionType,
 } from "@gnu-taler/taler-util";
 import {
@@ -818,7 +819,7 @@ function getCoinsFilter(req: GetPlanForOperationRequest): CoinsFilter {
 export function calculatePlanFormAvailableCoins(
   transactionType: TransactionType,
   amount: AmountJson,
-  mode: "effective" | "raw",
+  mode: TransactionAmountMode,
   availableCoins: AvailableCoins,
 ) {
   const operationType = getOperationType(transactionType);
@@ -828,7 +829,9 @@ export function calculatePlanFormAvailableCoins(
       usableCoins = selectCoinForOperation(
         operationType,
         amount,
-        mode === "effective" ? "net" : "gross",
+        mode === TransactionAmountMode.Effective
+          ? AmountMode.Net
+          : AmountMode.Gross,
         availableCoins,
       );
       break;
@@ -839,11 +842,11 @@ export function calculatePlanFormAvailableCoins(
       //are from that exchange
       const wireFee = Object.values(availableCoins.exchanges)[0].wireFee!;
 
-      if (mode === "effective") {
+      if (mode === TransactionAmountMode.Effective) {
         usableCoins = selectCoinForOperation(
           operationType,
           amount,
-          "gross",
+          AmountMode.Gross,
           availableCoins,
         );
 
@@ -857,7 +860,7 @@ export function calculatePlanFormAvailableCoins(
         usableCoins = selectCoinForOperation(
           operationType,
           adjustedAmount,
-          "net",
+          AmountMode.Net,
           availableCoins,
         );
 
@@ -914,6 +917,27 @@ export async function getPlanForOperation(
 }
 
 /**
+ * If the operation going to be plan subtracts
+ * or adds amount in the wallet db
+ */
+export enum OperationType {
+  Credit = "credit",
+  Debit = "debit",
+}
+
+/**
+ * How the amount should be interpreted
+ * net = without fee
+ * gross = with fee
+ *
+ * Net value is always lower than gross
+ */
+export enum AmountMode {
+  Net = "net",
+  Gross = "gross",
+}
+
+/**
  *
  * @param op defined which fee are we taking into consideration: deposits or withdraw
  * @param limit the total amount limit of the operation
@@ -922,9 +946,9 @@ export async function getPlanForOperation(
  * @returns
  */
 export function selectCoinForOperation(
-  op: "debit" | "credit",
+  op: OperationType,
   limit: AmountJson,
-  mode: "net" | "gross",
+  mode: AmountMode,
   coins: AvailableCoins,
 ): SelectedCoins {
   const result: SelectedCoins = {
@@ -951,8 +975,11 @@ export function selectCoinForOperation(
   iterateDenoms: while (denomIdx < coins.list.length) {
     const denom = coins.list[denomIdx];
     let total =
-      op === "credit" ? Number.MAX_SAFE_INTEGER : denom.totalAvailable ?? 0;
-    const opFee = op === "credit" ? denom.denomWithdraw : denom.denomDeposit;
+      op === OperationType.Credit
+        ? Number.MAX_SAFE_INTEGER
+        : denom.totalAvailable ?? 0;
+    const opFee =
+      op === OperationType.Credit ? denom.denomWithdraw : denom.denomDeposit;
     const contribution = Amounts.sub(denom.value, opFee).amount;
 
     if (Amounts.isZero(contribution)) {
@@ -969,7 +996,7 @@ export function selectCoinForOperation(
         contribution,
       ).amount;
 
-      const progress = mode === "gross" ? nextValue : nextContribution;
+      const progress = mode === AmountMode.Gross ? nextValue : nextContribution;
 
       if (Amounts.cmp(progress, limit) === 1) {
         //the current coin is more than we need, try next denom
@@ -1008,14 +1035,15 @@ export function selectCoinForOperation(
     // we made it
     return result;
   }
-  if (op === "credit") {
+  if (op === OperationType.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 total =
+    mode === AmountMode.Gross ? result.totalValue : result.totalContribution;
   const gap = Amounts.sub(limit, total).amount;
 
   //about recursive calls
@@ -1027,7 +1055,7 @@ export function selectCoinForOperation(
   refreshIteration: while (refreshIdx < coins.list.length) {
     const d = coins.list[refreshIdx];
     const denomContribution =
-      mode === "gross"
+      mode === AmountMode.Gross
         ? Amounts.sub(d.value, d.denomRefresh).amount
         : Amounts.sub(d.value, d.denomDeposit, d.denomRefresh).amount;
 
@@ -1038,7 +1066,7 @@ export function selectCoinForOperation(
     }
 
     const changeCost = selectCoinForOperation(
-      "credit",
+      OperationType.Credit,
       changeAfterDeposit,
       mode,
       coins,
@@ -1067,7 +1095,7 @@ export function selectCoinForOperation(
     refreshIdx++;
   }
   if (choice) {
-    if (mode === "gross") {
+    if (mode === AmountMode.Gross) {
       result.totalValue = Amounts.add(result.totalValue, gap).amount;
       result.totalContribution = Amounts.add(
         result.totalContribution,
@@ -1096,9 +1124,9 @@ export function selectCoinForOperation(
 }
 
 type CompareCoinsFunction = (d1: CoinInfo, d2: CoinInfo) => -1 | 0 | 1;
-function buildRankingForCoins(op: "debit" | "credit"): CompareCoinsFunction {
+function buildRankingForCoins(op: OperationType): CompareCoinsFunction {
   function getFee(d: CoinInfo) {
-    return op === "credit" ? d.denomWithdraw : d.denomDeposit;
+    return op === OperationType.Credit ? d.denomWithdraw : d.denomDeposit;
   }
   //different exchanges may have different wireFee
   //ranking should take the relative contribution in the exchange
@@ -1116,28 +1144,32 @@ function buildRankingForCoins(op: "debit" | "credit"): CompareCoinsFunction {
   };
 }
 
-function getOperationType(txType: TransactionType): "credit" | "debit" {
+function getOperationType(txType: TransactionType): OperationType {
   const operationType =
     txType === TransactionType.Withdrawal
-      ? ("credit" as const)
+      ? OperationType.Credit
       : txType === TransactionType.Deposit
-      ? ("debit" as const)
+      ? OperationType.Debit
       : undefined;
   if (!operationType) {
-    throw Error(`operation type ${txType} not supported`);
+    throw Error(`operation type ${txType} not yet supported`);
   }
   return operationType;
 }
 
 function getAmountsWithFee(
-  op: "debit" | "credit",
+  op: OperationType,
   value: AmountJson,
   contribution: AmountJson,
   details: any,
 ): GetPlanForOperationResponse {
   return {
-    rawAmount: Amounts.stringify(op === "credit" ? value : contribution),
-    effectiveAmount: Amounts.stringify(op === "credit" ? contribution : value),
+    rawAmount: Amounts.stringify(
+      op === OperationType.Credit ? value : contribution,
+    ),
+    effectiveAmount: Amounts.stringify(
+      op === OperationType.Credit ? contribution : value,
+    ),
     details,
   };
 }
@@ -1202,7 +1234,7 @@ interface CoinsFilter {
  */
 async function getAvailableCoins(
   ws: InternalWalletState,
-  op: "credit" | "debit",
+  op: OperationType,
   currency: string,
   filters: CoinsFilter = {},
 ): Promise<AvailableCoins> {
@@ -1286,7 +1318,7 @@ async function getAvailableCoins(
         let creditDeadline = AbsoluteTime.never();
         let debitDeadline = AbsoluteTime.never();
         //4.- filter coins restricted by age
-        if (op === "credit") {
+        if (op === OperationType.Credit) {
           const ds = await tx.denominations.indexes.byExchangeBaseUrl.getAll(
             exchangeBaseUrl,
           );