From 159c82eca59fbca8c5f7985acc26815821cd0d91 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Prohaszka?= <stephane.prohaszka@ledger.fr>
Date: Wed, 17 Jul 2024 08:49:13 +0200
Subject: [PATCH] feat(xlm): add combine function
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Stéphane Prohaszka <stephane.prohaszka@ledger.fr>
---
 .../coin-stellar/src/api/index.integ.test.ts  | 20 +++++++++----------
 .../coin-stellar/src/api/index.ts             | 14 ++++++++-----
 .../coin-stellar/src/logic/combine.ts         | 14 +++++++++++--
 .../coin-stellar/src/logic/index.ts           |  2 +-
 4 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/libs/coin-modules/coin-stellar/src/api/index.integ.test.ts b/libs/coin-modules/coin-stellar/src/api/index.integ.test.ts
index 0ea3b6ef83cd..214944310d97 100644
--- a/libs/coin-modules/coin-stellar/src/api/index.integ.test.ts
+++ b/libs/coin-modules/coin-stellar/src/api/index.integ.test.ts
@@ -46,17 +46,17 @@ describe("Stellar Api", () => {
     });
   });
 
-  // describe("lastBlock", () => {
-  //   it("returns last block info", async () => {
-  //     // When
-  //     const result = await module.lastBlock();
+  describe("lastBlock", () => {
+    it("returns last block info", async () => {
+      // When
+      const result = await module.lastBlock();
 
-  //     // Then
-  //     expect(result.hash).toBeDefined();
-  //     expect(result.height).toBeDefined();
-  //     expect(result.time).toBeInstanceOf(Date);
-  //   });
-  // });
+      // Then
+      expect(result.hash).toBeDefined();
+      expect(result.height).toBeDefined();
+      expect(result.time).toBeInstanceOf(Date);
+    });
+  });
 
   describe("getBalance", () => {
     it("returns a list regarding address parameter", async () => {
diff --git a/libs/coin-modules/coin-stellar/src/api/index.ts b/libs/coin-modules/coin-stellar/src/api/index.ts
index 3976b4a661d1..d1b00f4aa8b7 100644
--- a/libs/coin-modules/coin-stellar/src/api/index.ts
+++ b/libs/coin-modules/coin-stellar/src/api/index.ts
@@ -2,13 +2,12 @@ import type { Api } from "@ledgerhq/coin-framework/api/index";
 import coinConfig, { type StellarConfig } from "../config";
 import {
   broadcast,
-  // combine,
+  combine,
   craftTransaction,
   // estimateFees,
   getBalance,
   listOperations,
   lastBlock,
-  // rawEncode,
 } from "../logic";
 
 export function createApi(config: StellarConfig): Api {
@@ -16,9 +15,7 @@ export function createApi(config: StellarConfig): Api {
 
   return {
     broadcast,
-    combine: () => {
-      throw new Error("Method not supported");
-    },
+    combine: compose,
     craftTransaction: craft,
     estimateFees: () => Promise.reject(new Error("Method not supported")),
     getBalance,
@@ -66,3 +63,10 @@ async function craft(
   );
   return tx.xdr;
 }
+
+function compose(tx: string, signature: string, pubkey?: string): string {
+  if (!pubkey) {
+    throw new Error("Missing pubkey");
+  }
+  return combine(tx, signature, pubkey);
+}
diff --git a/libs/coin-modules/coin-stellar/src/logic/combine.ts b/libs/coin-modules/coin-stellar/src/logic/combine.ts
index 40bd5104d2f0..abbc9ac001bc 100644
--- a/libs/coin-modules/coin-stellar/src/logic/combine.ts
+++ b/libs/coin-modules/coin-stellar/src/logic/combine.ts
@@ -1,3 +1,13 @@
+import { Transaction as StellarSdkTransaction } from "@stellar/stellar-sdk";
 
-// export function combine(transaction: string, signature: string, publicKey?: string): string {
-// }
+// https://developers.stellar.org/docs/learn/encyclopedia/network-configuration/network-passphrases
+// Mainnet
+const NETWORK_PASSPHRASE = "Public Global Stellar Network ; September 2015";
+// Testnet
+// const NETWORK_PASSPHRASE = "Test SDF Network ; September 2015";
+
+export function combine(transaction: string, signature: string, publicKey: string): string {
+  const unsignedTx = new StellarSdkTransaction(transaction, NETWORK_PASSPHRASE);
+  unsignedTx.addSignature(publicKey, signature);
+  return unsignedTx.toXDR();
+}
diff --git a/libs/coin-modules/coin-stellar/src/logic/index.ts b/libs/coin-modules/coin-stellar/src/logic/index.ts
index d3954ac7a826..5605cbf5e923 100644
--- a/libs/coin-modules/coin-stellar/src/logic/index.ts
+++ b/libs/coin-modules/coin-stellar/src/logic/index.ts
@@ -1,5 +1,5 @@
 export { broadcast } from "./broadcast";
-// export { combine } from "./combine";
+export { combine } from "./combine";
 export { craftTransaction } from "./craftTransaction";
 // export { estimateFees } from "./estimateFees";
 export { getBalance } from "./getBalance";