refactor: introduce adapter layer for Djed transaction handling

.gitignore

@@ -0,0 +1,2 @@
+djed-sdk/.npmrc
+package-lock.json

djed-sdk/src/adapters/djedAdapter.js

@@ -0,0 +1,33 @@
+import { FEE_UI_UNSCALED } from "../djed/tradeUtils";
+
+export const createDjedAdapter = (djedContract) => {
+  const methods = djedContract?.methods;
+
+  const missingMethods = [];
+
+  if (!methods) {
+    throw new Error("Invalid Djed contract instance: methods object is missing");
+  }
+
+  if (typeof methods.buyStableCoins !== "function") {
+    missingMethods.push("buyStableCoins");
+  }
+
+  if (typeof methods.sellStableCoins !== "function") {
+    missingMethods.push("sellStableCoins");
+  }
+
+  if (missingMethods.length > 0) {
+    throw new Error(
+      `Djed contract is missing required methods: ${missingMethods.join(", ")}`
+    );
+  }
+
+  return {
+    buyStableCoins: (receiver, ui) =>
+      methods.buyStableCoins(receiver, FEE_UI_UNSCALED, ui),
+
+    sellStableCoins: (amount, account, ui) =>
+      methods.sellStableCoins(amount, account, FEE_UI_UNSCALED, ui),
+  };
+};

djed-sdk/src/djed/djed.js

@@ -1,6 +1,7 @@
 import djedArtifact from "../artifacts/DjedABI.json";
 import coinArtifact from "../artifacts/CoinABI.json";
-import { convertInt, web3Promise } from "../helpers";
+import { convertInt, web3Promise, buildTx } from "../helpers";
+import { createDjedAdapter } from "../adapters/djedAdapter";
 
 //setting up djed
 export const getDjedContract = (web3, DJED_ADDRESS) => {
@@ -27,3 +28,14 @@ export const getDecimals = async (stableCoin, reserveCoin) => {
   ]);
   return { scDecimals, rcDecimals };
 };
+
+// Adapter should be created once and passed in (dependency injection)
+const buyScTx = (adapter, payer, receiver, value, ui, DJED_ADDRESS) => {
+  const data = adapter.buyStableCoins(receiver, ui).encodeABI();
+  return buildTx(payer, DJED_ADDRESS, value, data);
+};
+
+const sellScTx = (adapter, account, amount, ui, DJED_ADDRESS) => {
+  const data = adapter.sellStableCoins(amount, account, ui).encodeABI();
+  return buildTx(account, DJED_ADDRESS, 0, data);
+};