From ee48a39eb370e65564317f7c77e2cd52e8a0c42f Mon Sep 17 00:00:00 2001
From: Sebastian <sebasjm@gmail.com>
Date: Thu, 14 Sep 2023 10:56:34 -0300
Subject: [PATCH] merchant payment

---
 .../src/util/coinSelection.test.ts            | 103 ++++++++++++++----
 .../src/util/coinSelection.ts                 |   5 +-
 2 files changed, 87 insertions(+), 21 deletions(-)

diff --git a/packages/taler-wallet-core/src/util/coinSelection.test.ts b/packages/taler-wallet-core/src/util/coinSelection.test.ts
index 2a322c4a9..f809c4e60 100644
--- a/packages/taler-wallet-core/src/util/coinSelection.test.ts
+++ b/packages/taler-wallet-core/src/util/coinSelection.test.ts
@@ -24,23 +24,7 @@ import {
   TransactionAmountMode,
 } from "@gnu-taler/taler-util";
 import test, { ExecutionContext } from "ava";
-import { AvailableDenom, testing_greedySelectPeer } from "./coinSelection.js"
-
-type Tester<T> = {
-  deep: {
-    equal(another: T): ReturnType<ExecutionContext["deepEqual"]>;
-    equals(another: T): ReturnType<ExecutionContext["deepEqual"]>;
-  }
-}
-
-function expect<T>(t: ExecutionContext, thing: T): Tester<T> {
-  return {
-    deep: {
-      equal: (another: T) => t.deepEqual(thing, another),
-      equals: (another: T) => t.deepEqual(thing, another),
-    },
-  };
-}
+import { AvailableDenom, testing_greedySelectPeer, testing_selectGreedy } from "./coinSelection.js"
 
 const inTheDistantFuture = AbsoluteTime.toProtocolTimestamp(
   AbsoluteTime.addDuration(AbsoluteTime.now(), Duration.fromSpec({ hours: 1 }))
@@ -49,7 +33,7 @@ const inThePast = AbsoluteTime.toProtocolTimestamp(
   AbsoluteTime.subtractDuraction(AbsoluteTime.now(), Duration.fromSpec({ hours: 1 }))
 )
 
-test("should select the coin", (t) => {
+test("p2p: should select the coin", (t) => {
   const instructedAmount = Amounts.parseOrThrow("LOCAL:2")
   const tally = {
     amountAcc: Amounts.zeroOfCurrency(instructedAmount.currency),
@@ -84,7 +68,7 @@ test("should select the coin", (t) => {
 
 });
 
-test("should select 3 coins", (t) => {
+test("p2p: should select 3 coins", (t) => {
   const instructedAmount = Amounts.parseOrThrow("LOCAL:20")
   const tally = {
     amountAcc: Amounts.zeroOfCurrency(instructedAmount.currency),
@@ -123,7 +107,7 @@ test("should select 3 coins", (t) => {
 
 });
 
-test("can't select since the instructed amount is too high", (t) => {
+test("p2p: can't select since the instructed amount is too high", (t) => {
   const instructedAmount = Amounts.parseOrThrow("LOCAL:60")
   const tally = {
     amountAcc: Amounts.zeroOfCurrency(instructedAmount.currency),
@@ -151,6 +135,68 @@ test("can't select since the instructed amount is too high", (t) => {
 
 });
 
+test("pay: select one coin to pay with fee", (t) => {
+  const payment = Amounts.parseOrThrow("LOCAL:2")
+  const exchangeWireFee = Amounts.parseOrThrow("LOCAL:0.1")
+  const zero = Amounts.zeroOfCurrency(payment.currency)
+  const tally = {
+    amountPayRemaining: payment,
+    amountWireFeeLimitRemaining: zero,
+    amountDepositFeeLimitRemaining: zero,
+    customerDepositFees: zero,
+    customerWireFees: zero,
+    wireFeeCoveredForExchange: new Set<string>(),
+    lastDepositFee: zero,
+  };
+  const coins = testing_selectGreedy(
+    {
+      "auditors": [],
+      "exchanges": [
+          {
+              "exchangeBaseUrl": "http://exchange.localhost/",
+              "exchangePub": "E5M8CGRDHXF1RCVP3B8TQCTDYNQ7T4XHWR5SVEQRGVVMVME41VJ0"
+          }
+      ],
+      "contractTermsAmount": payment,
+      "depositFeeLimit": zero,
+      "wireFeeAmortization": 1,
+      "wireFeeLimit": zero,
+      "prevPayCoins": [],
+      "wireMethod": "x-taler-bank"
+    },
+    createCandidates([{
+      amount: "LOCAL:10",
+      numAvailable: 5,
+      depositFee: "LOCAL:0.1",
+      fromExchange: "http://exchange.localhost/",
+    }]),
+    {"http://exchange.localhost/": exchangeWireFee}, 
+    tally
+  );
+
+  expect(t, coins).deep.equal({
+    "hash0;32;http://exchange.localhost/": {
+      exchangeBaseUrl: "http://exchange.localhost/",
+      denomPubHash: "hash0",
+      maxAge: 32,
+      contributions: [
+        Amounts.parseOrThrow("LOCAL:2.2"),
+      ],
+    }
+  });
+
+  expect(t, tally).deep.equal({
+    amountPayRemaining: Amounts.parseOrThrow("LOCAL:2"),
+    amountWireFeeLimitRemaining: zero,
+    amountDepositFeeLimitRemaining: zero,
+    customerDepositFees: zero,
+    customerWireFees: zero,
+    wireFeeCoveredForExchange: new Set(),
+    lastDepositFee: zero,
+  });
+
+});
+
 
 
 
@@ -179,3 +225,20 @@ function createCandidates(ar: {amount: AmountString, depositFee: AmountString, n
     }
   })
 }
+
+type Tester<T> = {
+  deep: {
+    equal(another: T): ReturnType<ExecutionContext["deepEqual"]>;
+    equals(another: T): ReturnType<ExecutionContext["deepEqual"]>;
+  }
+}
+
+function expect<T>(t: ExecutionContext, thing: T): Tester<T> {
+  return {
+    deep: {
+      equal: (another: T) => t.deepEqual(thing, another),
+      equals: (another: T) => t.deepEqual(thing, another),
+    },
+  };
+}
+
diff --git a/packages/taler-wallet-core/src/util/coinSelection.ts b/packages/taler-wallet-core/src/util/coinSelection.ts
index 0885215dd..0b1be881f 100644
--- a/packages/taler-wallet-core/src/util/coinSelection.ts
+++ b/packages/taler-wallet-core/src/util/coinSelection.ts
@@ -419,6 +419,9 @@ interface SelResult {
   };
 }
 
+export function testing_selectGreedy(...args: Parameters<typeof selectGreedy>): ReturnType<typeof selectGreedy>{
+  return selectGreedy(...args)
+}
 function selectGreedy(
   req: SelectPayCoinRequestNg,
   candidateDenoms: AvailableDenom[],
@@ -930,7 +933,7 @@ function greedySelectPeer(
       ).amount;
 
       tally.lastDepositFee = Amounts.parseOrThrow(denom.feeDeposit);
-      
+
       contributions.push(coinSpend);
     }
     if (contributions.length > 0) {