BODMAT · BODMAT · May 24, 2026 · May 24, 2026
diff --git a/apps/backend/prisma/migrations/20260524120000_normalize_stable_coin/migration.sql b/apps/backend/prisma/migrations/20260524120000_normalize_stable_coin/migration.sql
@@ -0,0 +1,9 @@
+-- Replace stableCoins TEXT[] with a single scalar stableCoin TEXT to satisfy 1NF.
+-- Existing rows keep the first element of the array (fallback to 'usdt' if NULL/empty).
+
+ALTER TABLE "SwapSettings" ADD COLUMN "stableCoin" TEXT NOT NULL DEFAULT 'usdt';
+
+UPDATE "SwapSettings"
+SET "stableCoin" = COALESCE("stableCoins"[1], 'usdt');
+
+ALTER TABLE "SwapSettings" DROP COLUMN "stableCoins";
diff --git a/apps/backend/prisma/schema.prisma b/apps/backend/prisma/schema.prisma
@@ -105,6 +105,6 @@ model SwapSettings {
   id          String   @id @default(uuid())
   walletId    String   @unique
   swapEnabled Boolean  @default(false)
-  stableCoins String[] @default(["usdt", "usdc"])
+  stableCoin  String   @default("usdt")
   wallet      Wallet   @relation(fields: [walletId], references: [id], onDelete: Cascade)
 }
diff --git a/apps/backend/prisma/seed.ts b/apps/backend/prisma/seed.ts
@@ -627,7 +627,12 @@ async function main() {
     ],
   ];
 
-  const coinCycle: ("btc" | "eth" | "sol" | "bnb")[] = ["btc", "eth", "sol", "bnb"];
+  const coinCycle: ("btc" | "eth" | "sol" | "bnb")[] = [
+    "btc",
+    "eth",
+    "sol",
+    "bnb",
+  ];
   const basePrices: Record<string, number> = {
     btc: 65000,
     eth: 3100,
@@ -689,24 +694,24 @@ async function main() {
   // ===== SwapSettings (one per wallet, hand-crafted) =====
   // walletId is @unique on SwapSettings, so one row per chosen wallet.
   const swapSettings = [
-    { walletId: wallets[0].id, swapEnabled: true, stableCoins: ["usdt", "usdc"] },
-    { walletId: wallets[1].id, swapEnabled: false, stableCoins: ["usdt"] },
-    { walletId: wallets[2].id, swapEnabled: true, stableCoins: ["usdt", "usdc", "dai"] },
-    { walletId: wallets[3].id, swapEnabled: true, stableCoins: ["usdc"] },
-    { walletId: wallets[4].id, swapEnabled: false, stableCoins: ["usdt", "usdc"] },
-    { walletId: wallets[5].id, swapEnabled: true, stableCoins: ["usdt"] },
-    { walletId: wallets[6].id, swapEnabled: true, stableCoins: ["usdt", "usdc"] },
-    { walletId: wallets[7].id, swapEnabled: false, stableCoins: ["usdc"] },
-    { walletId: wallets[8].id, swapEnabled: true, stableCoins: ["usdt", "dai"] },
-    { walletId: wallets[9].id, swapEnabled: true, stableCoins: ["usdt", "usdc"] },
-    { walletId: wallets[10].id, swapEnabled: false, stableCoins: ["usdt"] },
-    { walletId: wallets[11].id, swapEnabled: true, stableCoins: ["usdc", "dai"] },
-    { walletId: wallets[12].id, swapEnabled: true, stableCoins: ["usdt", "usdc"] },
-    { walletId: wallets[13].id, swapEnabled: true, stableCoins: ["usdt"] },
-    { walletId: wallets[14].id, swapEnabled: false, stableCoins: ["usdt", "usdc"] },
-    { walletId: wallets[15].id, swapEnabled: true, stableCoins: ["usdt", "usdc", "dai"] },
-    { walletId: wallets[16].id, swapEnabled: true, stableCoins: ["usdc"] },
-    { walletId: wallets[17].id, swapEnabled: false, stableCoins: ["usdt", "usdc"] },
+    { walletId: wallets[0].id, swapEnabled: true, stableCoin: "usdt" },
+    { walletId: wallets[1].id, swapEnabled: false, stableCoin: "usdt" },
+    { walletId: wallets[2].id, swapEnabled: true, stableCoin: "usdt" },
+    { walletId: wallets[3].id, swapEnabled: true, stableCoin: "usdc" },
+    { walletId: wallets[4].id, swapEnabled: false, stableCoin: "usdt" },
+    { walletId: wallets[5].id, swapEnabled: true, stableCoin: "usdt" },
+    { walletId: wallets[6].id, swapEnabled: true, stableCoin: "usdt" },
+    { walletId: wallets[7].id, swapEnabled: false, stableCoin: "usdc" },
+    { walletId: wallets[8].id, swapEnabled: true, stableCoin: "usdt" },
+    { walletId: wallets[9].id, swapEnabled: true, stableCoin: "usdt" },
+    { walletId: wallets[10].id, swapEnabled: false, stableCoin: "usdt" },
+    { walletId: wallets[11].id, swapEnabled: true, stableCoin: "usdc" },
+    { walletId: wallets[12].id, swapEnabled: true, stableCoin: "usdt" },
+    { walletId: wallets[13].id, swapEnabled: true, stableCoin: "usdt" },
+    { walletId: wallets[14].id, swapEnabled: false, stableCoin: "usdt" },
+    { walletId: wallets[15].id, swapEnabled: true, stableCoin: "usdt" },
+    { walletId: wallets[16].id, swapEnabled: true, stableCoin: "usdc" },
+    { walletId: wallets[17].id, swapEnabled: false, stableCoin: "usdt" },
   ].map((row) => ({ id: randomUUID(), ...row }));
 
   await prisma.swapSettings.createMany({ data: swapSettings });
@@ -771,7 +776,8 @@ async function main() {
       createdAt: dateDaysAgo(4),
       revokedAt: null,
       replacedByTokenHash: null,
-      userAgent: "Mozilla/5.0 (Macintosh; Intel Mac OS X 14_4) Chrome/124.0.0.0",
+      userAgent:
+        "Mozilla/5.0 (Macintosh; Intel Mac OS X 14_4) Chrome/124.0.0.0",
       ip: "82.118.20.5",
     },
     {
@@ -781,7 +787,8 @@ async function main() {
       createdAt: dateDaysAgo(35),
       revokedAt: null,
       replacedByTokenHash: null,
-      userAgent: "Mozilla/5.0 (Macintosh; Intel Mac OS X 14_4) Chrome/123.0.0.0",
+      userAgent:
+        "Mozilla/5.0 (Macintosh; Intel Mac OS X 14_4) Chrome/123.0.0.0",
       ip: "82.118.20.5",
     },
     {
@@ -821,7 +828,8 @@ async function main() {
       createdAt: dateDaysAgo(2),
       revokedAt: null,
       replacedByTokenHash: null,
-      userAgent: "Mozilla/5.0 (Windows NT 10.0; rv:126.0) Gecko/20100101 Firefox/126.0",
+      userAgent:
+        "Mozilla/5.0 (Windows NT 10.0; rv:126.0) Gecko/20100101 Firefox/126.0",
       ip: "176.36.10.55",
     },
     {

diff --git a/apps/backend/src/controllers/swapController.ts b/apps/backend/src/controllers/swapController.ts
@@ -199,7 +199,7 @@ export const getSwapSettings = async (req: Request, res: Response) => {
       return res.status(200).json({
         walletId,
         swapEnabled: false,
-        stableCoins: ["usdt", "usdc"],
+        stableCoin: "usdt",
       });
     }
 
@@ -223,22 +223,22 @@ export const updateSwapSettings = async (req: Request, res: Response) => {
       return handleZodError(res, validationResult.error);
     }
 
-    const { swapEnabled, stableCoins } = validationResult.data;
+    const { swapEnabled, stableCoin } = validationResult.data;
 
-    if (swapEnabled === undefined && stableCoins === undefined) {
+    if (swapEnabled === undefined && stableCoin === undefined) {
       return res.status(400).json({ error: "No fields provided for update." });
     }
 
     const settings = await prisma.swapSettings.upsert({
       where: { walletId },
       update: {
         ...(swapEnabled !== undefined ? { swapEnabled } : {}),
-        ...(stableCoins !== undefined ? { stableCoins } : {}),
+        ...(stableCoin !== undefined ? { stableCoin } : {}),
       },
       create: {
         walletId,
         swapEnabled: swapEnabled ?? false,
-        stableCoins: stableCoins ?? ["usdt", "usdc"],
+        stableCoin: stableCoin ?? "usdt",
       },
     });
 

diff --git a/apps/backend/src/controllers/transaction/transactionCrudHandlers.ts b/apps/backend/src/controllers/transaction/transactionCrudHandlers.ts
@@ -303,6 +303,54 @@ export const deleteTransaction = async (req: Request, res: Response) => {
     if (!transactionToDelete)
       return res.status(404).json({ error: "Transaction not found" });
 
+    // Swap: cascade-delete both legs atomically
+    if (transactionToDelete.swapGroupId !== null) {
+      const swapGroupId = transactionToDelete.swapGroupId;
+
+      const swapGroup = await prisma.$queryRaw<TransactionRow[]>`
+        SELECT
+          "id", "walletId", "coinSymbol", "swapGroupId",
+          "buyOrSell", "price", "quantity", "createdAt", "updatedAt"
+        FROM "Transaction"
+        WHERE "swapGroupId" = ${swapGroupId};
+      `;
+
+      // Validate balance only for the buy leg
+      for (const swapTx of swapGroup) {
+        if (swapTx.buyOrSell !== "buy") continue;
+
+        const remaining = await prisma.$queryRaw<
+          { buyOrSell: "buy" | "sell"; quantity: number | string }[]
+        >`
+          SELECT "buyOrSell", "quantity"
+          FROM "Transaction"
+          WHERE
+            "walletId" = ${walletId}
+            AND "coinSymbol" = ${swapTx.coinSymbol}
+            AND "swapGroupId" IS DISTINCT FROM ${swapGroupId}
+          ORDER BY "createdAt" ASC, "id" ASC;
+        `;
+
+        let runningBalance = 0;
+        for (const tx of remaining) {
+          const qty = Number(tx.quantity);
+          runningBalance += tx.buyOrSell === "buy" ? qty : -qty;
+          if (runningBalance < 0) {
+            return res.status(400).json({
+              error: `Cannot delete swap. This would break chronological balance for ${swapTx.coinSymbol.toUpperCase()}.`,
+            });
+          }
+        }
+      }
+
+      await prisma.$executeRaw`
+        DELETE FROM "Transaction"
+        WHERE "swapGroupId" = ${swapGroupId};
+      `;
+
+      return res.status(200).json({ message: "Swap deleted", swapGroupId });
+    }
+
     const symbol = transactionToDelete.coinSymbol;
 
     if (transactionToDelete.buyOrSell === "buy") {
@@ -408,6 +456,13 @@ export const updateTransaction = async (req: Request, res: Response) => {
     if (!oldTransaction)
       return res.status(404).json({ error: "Transaction not found" });
 
+    if (oldTransaction.swapGroupId !== null) {
+      return res.status(403).json({
+        error:
+          "Swap transactions cannot be edited individually. Delete the swap to remove both legs.",
+      });
+    }
+
     const validationResult = CreateTransactionDto.omit({
       walletId: true,
       coinSymbol: true,

diff --git a/apps/backend/src/models/SwapSchema.ts b/apps/backend/src/models/SwapSchema.ts
@@ -12,5 +12,5 @@ export const CreateSwapSchema = z.object({
 
 export const UpdateSwapSettingsSchema = z.object({
   swapEnabled: z.boolean().optional(),
-  stableCoins: z.array(z.string().trim().toLowerCase().min(1)).optional(),
+  stableCoin: z.string().trim().toLowerCase().min(1).optional(),
 });
diff --git a/apps/backend/tests/helpers/testUtils.ts b/apps/backend/tests/helpers/testUtils.ts
@@ -70,7 +70,7 @@ export const enableSwap = async (agent: TestAgent, walletId: string) => {
     .patch(`/api/wallets/${walletId}/swap-settings`)
     .send({
       swapEnabled: true,
-      stableCoins: ["usdt", "usdc"],
+      stableCoin: "usdt",
     });
 
   if (response.status !== 200) {

diff --git a/apps/frontend/src/modules/Transactions/AddTransactionPopup.tsx b/apps/frontend/src/modules/Transactions/AddTransactionPopup.tsx
@@ -49,9 +49,7 @@ export function AddTransactionPopup({ coin }: { coin: Coin }) {
   const currentCoinInWallet = coinStats?.totalQuantity || 0;
   const averageBuyingPrice = coinStats?.avgBuyingPrice || 0;
   const swapEnabled = swapSettings?.swapEnabled ?? false;
-  const activeStableCoin = (
-    swapSettings?.stableCoins?.[0] || "usdt"
-  ).toUpperCase();
+  const activeStableCoin = (swapSettings?.stableCoin || "usdt").toUpperCase();
   const isLoading = isCreateTransactionLoading || isCreateSwapLoading;
 
   const handleChange = (
@@ -93,9 +91,7 @@ export function AddTransactionPopup({ coin }: { coin: Coin }) {
 
     try {
       if (form.buyOrSell === "buy" && swapEnabled && payWithSwap) {
-        const stableCoin = (
-          swapSettings?.stableCoins?.[0] || "usdt"
-        ).toLowerCase();
+        const stableCoin = (swapSettings?.stableCoin || "usdt").toLowerCase();
         const totalToSpend = Number(
           form.total_price ||
             (Number(form.quantity) * Number(form.price)).toString(),
@@ -114,9 +110,7 @@ export function AddTransactionPopup({ coin }: { coin: Coin }) {
           },
         }).unwrap();
       } else if (form.buyOrSell === "sell" && swapEnabled && payWithSwap) {
-        const stableCoin = (
-          swapSettings?.stableCoins?.[0] || "usdt"
-        ).toLowerCase();
+        const stableCoin = (swapSettings?.stableCoin || "usdt").toLowerCase();
         const stableQuantity = Number(
           form.total_price ||
             (Number(form.quantity) * Number(form.price)).toString(),

diff --git a/apps/frontend/src/modules/Transactions/ChangeTransactionPopup.tsx b/apps/frontend/src/modules/Transactions/ChangeTransactionPopup.tsx
@@ -69,6 +69,8 @@ export function ChangeTransactionPopup({
   if (!selectedWalletId || isLoading || !transaction)
     return <div className="p-4 text-center">Loading...</div>;
 
+  const isSwap = !!transaction.swapGroupId;
+
   const currentCoinInWallet = coinStats?.totalQuantity || 0;
 
   const handleChange = (
@@ -164,7 +166,13 @@ export function ChangeTransactionPopup({
         </div>
       </div>
 
-      {alert && (
+      {isSwap && (
+        <div className="bg-sky-500/10 text-sky-300 border border-sky-400/30 p-3 rounded text-sm text-center">
+          Swap transactions cannot be edited individually.
+        </div>
+      )}
+
+      {!isSwap && alert && (
         <div className="bg-red-100 text-red-700 p-2 rounded border border-red-200 text-sm text-center">
           {alert}
         </div>
@@ -174,7 +182,7 @@ export function ChangeTransactionPopup({
         className="flex flex-col gap-4"
         onSubmit={(e) => {
           e.preventDefault();
-          handleSubmit();
+          if (!isSwap) handleSubmit();
         }}
       >
         <TransactionFormFields
@@ -184,6 +192,7 @@ export function ChangeTransactionPopup({
           isLoading={isUpdating}
           submitLabel="Update Transaction"
           loadingLabel="Saving..."
+          disabled={isSwap}
         />
       </form>
     </div>

diff --git a/apps/frontend/src/modules/Transactions/SwapDeleteConfirmPopup.tsx b/apps/frontend/src/modules/Transactions/SwapDeleteConfirmPopup.tsx
@@ -0,0 +1,60 @@
+import { useAppDispatch } from "../../store";
+import { closePopup, openPopup } from "../../portals/popup.slice";
+import { useDeleteTransactionMutation } from "./transaction.api";
+import { extractApiErrorMessage } from "../../utils/functions";
+
+export function SwapDeleteConfirmPopup({
+  walletId,
+  transactionId,
+}: {
+  walletId: string;
+  transactionId: string;
+}) {
+  const dispatch = useAppDispatch();
+  const [deleteTransaction, { isLoading }] = useDeleteTransactionMutation();
+
+  const handleConfirm = async () => {
+    try {
+      await deleteTransaction({ walletId, transactionId }).unwrap();
+      dispatch(closePopup());
+      setTimeout(() => {
+        dispatch(
+          openPopup({ title: "Success", children: "Transaction deleted!" }),
+        );
+      }, 300);
+    } catch (error: unknown) {
+      dispatch(closePopup());
+      const message = extractApiErrorMessage(error);
+      setTimeout(() => {
+        dispatch(openPopup({ title: "Failure", children: message }));
+      }, 300);
+    }
+  };
+
+  return (
+    <div className="flex flex-col gap-6 p-2">
+      <p className="text-sm text-center leading-relaxed">
+        This transaction is part of a swap. Deleting it will also remove the
+        linked transaction.{" "}
+        <span className="font-bold">Both will be permanently deleted.</span>
+      </p>
+
+      <div className="flex gap-3 justify-center">
+        <button
+          onClick={() => dispatch(closePopup())}
+          disabled={isLoading}
+          className="px-5 py-2 rounded border border-gray-400 text-sm disabled:opacity-50 cursor-pointer hover:bg-gray-500/20 transition-colors"
+        >
+          Cancel
+        </button>
+        <button
+          onClick={handleConfirm}
+          disabled={isLoading}
+          className="px-5 py-2 rounded bg-red-600 text-white text-sm disabled:opacity-50 cursor-pointer hover:bg-red-700 transition-colors"
+        >
+          {isLoading ? "Deleting..." : "Confirm"}
+        </button>
+      </div>
+    </div>
+  );
+}