src/constants/notifications.ts

@@ -1689,3 +1689,11 @@ export const NOTIFY_CONTACTS_ADDED_CONFIRM = {
   title: "They're Added To Your List",
   message: "Would you like to go to the main page now?",
 };
+
+// ImportAccountView.vue specific constants
+// Used in: ImportAccountView.vue (onImportClick method - duplicate account warning)
+export const NOTIFY_DUPLICATE_ACCOUNT_IMPORT = {
+  title: "Account Already Imported",
+  message:
+    "This account has already been imported. Please use a different seed phrase or check your existing accounts.",
+};

src/libs/util.ts

@@ -614,57 +614,64 @@ export const retrieveAllAccountsMetadata = async (): Promise<
   return result;
 };
 
+export const DUPLICATE_ACCOUNT_ERROR = "Cannot import duplicate account.";
+
 /**
- * Saves a new identity to both SQL and Dexie databases
+ * Saves a new identity to SQL database
  */
 export async function saveNewIdentity(
   identity: IIdentifier,
   mnemonic: string,
   derivationPath: string,
 ): Promise<void> {
-  try {
-    // add to the new sql db
-    const platformService = await getPlatformService();
-
-    const secrets = await platformService.dbQuery(
-      `SELECT secretBase64 FROM secret`,
-    );
-    if (!secrets?.values?.length || !secrets.values[0]?.length) {
-      throw new Error(
-        "No initial encryption supported. We recommend you clear your data and start over.",
-      );
-    }
+  // add to the new sql db
+  const platformService = await getPlatformService();
 
-    const secretBase64 = secrets.values[0][0] as string;
+  // Check if account already exists before attempting to save
+  const existingAccount = await platformService.dbQuery(
+    "SELECT did FROM accounts WHERE did = ?",
+    [identity.did],
+  );
 
-    const secret = base64ToArrayBuffer(secretBase64);
-    const identityStr = JSON.stringify(identity);
-    const encryptedIdentity = await simpleEncrypt(identityStr, secret);
-    const encryptedMnemonic = await simpleEncrypt(mnemonic, secret);
-    const encryptedIdentityBase64 = arrayBufferToBase64(encryptedIdentity);
-    const encryptedMnemonicBase64 = arrayBufferToBase64(encryptedMnemonic);
+  if (existingAccount?.values?.length) {
+    throw new Error(
+      `Account with DID ${identity.did} already exists. ${DUPLICATE_ACCOUNT_ERROR}`,
+    );
+  }
 
-    const sql = `INSERT INTO accounts (dateCreated, derivationPath, did, identityEncrBase64, mnemonicEncrBase64, publicKeyHex)
-       VALUES (?, ?, ?, ?, ?, ?)`;
-    const params = [
-      new Date().toISOString(),
-      derivationPath,
-      identity.did,
-      encryptedIdentityBase64,
-      encryptedMnemonicBase64,
-      identity.keys[0].publicKeyHex,
-    ];
-    await platformService.dbExec(sql, params);
-
-    await platformService.updateDefaultSettings({ activeDid: identity.did });
-
-    await platformService.insertNewDidIntoSettings(identity.did);
-  } catch (error) {
-    logger.error("Failed to update default settings:", error);
+  const secrets = await platformService.dbQuery(
+    `SELECT secretBase64 FROM secret`,
+  );
+  if (!secrets?.values?.length || !secrets.values[0]?.length) {
     throw new Error(
-      "Failed to set default settings. Please try again or restart the app.",
+      "No initial encryption supported. We recommend you clear your data and start over.",
     );
   }
+
+  const secretBase64 = secrets.values[0][0] as string;
+
+  const secret = base64ToArrayBuffer(secretBase64);
+  const identityStr = JSON.stringify(identity);
+  const encryptedIdentity = await simpleEncrypt(identityStr, secret);
+  const encryptedMnemonic = await simpleEncrypt(mnemonic, secret);
+  const encryptedIdentityBase64 = arrayBufferToBase64(encryptedIdentity);
+  const encryptedMnemonicBase64 = arrayBufferToBase64(encryptedMnemonic);
+
+  const sql = `INSERT INTO accounts (dateCreated, derivationPath, did, identityEncrBase64, mnemonicEncrBase64, publicKeyHex)
+      VALUES (?, ?, ?, ?, ?, ?)`;
+  const params = [
+    new Date().toISOString(),
+    derivationPath,
+    identity.did,
+    encryptedIdentityBase64,
+    encryptedMnemonicBase64,
+    identity.keys[0].publicKeyHex,
+  ];
+  await platformService.dbExec(sql, params);
+
+  await platformService.updateDefaultSettings({ activeDid: identity.did });
+
+  await platformService.insertNewDidIntoSettings(identity.did);
 }
 
 /**
@@ -1032,3 +1039,58 @@ export async function importFromMnemonic(
     }
   }
 }
+
+/**
+ * Checks if an account with the given DID already exists in the database
+ *
+ * @param did - The DID to check for duplicates
+ * @returns Promise<boolean> - True if account already exists, false otherwise
+ * @throws Error if database query fails
+ */
+export async function checkForDuplicateAccount(did: string): Promise<boolean>;
+
+/**
+ * Checks if an account with the given DID already exists in the database
+ *
+ * @param mnemonic - The mnemonic phrase to derive DID from
+ * @param derivationPath - The derivation path to use
+ * @returns Promise<boolean> - True if account already exists, false otherwise
+ * @throws Error if database query fails
+ */
+export async function checkForDuplicateAccount(
+  mnemonic: string,
+  derivationPath: string,
+): Promise<boolean>;
+
+/**
+ * Implementation of checkForDuplicateAccount with overloaded signatures
+ */
+export async function checkForDuplicateAccount(
+  didOrMnemonic: string,
+  derivationPath?: string,
+): Promise<boolean> {
+  let didToCheck: string;
+
+  if (derivationPath) {
+    // Derive the DID from mnemonic and derivation path
+    const [address, privateHex, publicHex] = deriveAddress(
+      didOrMnemonic.trim().toLowerCase(),
+      derivationPath,
+    );
+
+    const newId = newIdentifier(address, privateHex, publicHex, derivationPath);
+    didToCheck = newId.did;
+  } else {
+    // Use the provided DID directly
+    didToCheck = didOrMnemonic;
+  }
+
+  // Check if an account with this DID already exists
+  const platformService = await getPlatformService();
+  const existingAccount = await platformService.dbQuery(
+    "SELECT did FROM accounts WHERE did = ?",
+    [didToCheck],
+  );
+
+  return (existingAccount?.values?.length ?? 0) > 0;
+}

src/views/ImportAccountView.vue

@@ -88,9 +88,15 @@ import { Router } from "vue-router";
 
 import { AppString, NotificationIface } from "../constants/app";
 import { DEFAULT_ROOT_DERIVATION_PATH } from "../libs/crypto";
-import { retrieveAccountCount, importFromMnemonic } from "../libs/util";
+import {
+  retrieveAccountCount,
+  importFromMnemonic,
+  checkForDuplicateAccount,
+  DUPLICATE_ACCOUNT_ERROR,
+} from "../libs/util";
 import { PlatformServiceMixin } from "@/utils/PlatformServiceMixin";
 import { createNotifyHelpers, TIMEOUTS } from "@/utils/notify";
+import { NOTIFY_DUPLICATE_ACCOUNT_IMPORT } from "@/constants/notifications";
 
 /**
  * Import Account View Component
@@ -198,6 +204,19 @@ export default class ImportAccountView extends Vue {
     }
 
     try {
+      // Check for duplicate account before importing
+      const isDuplicate = await checkForDuplicateAccount(
+        this.mnemonic,
+        this.derivationPath,
+      );
+      if (isDuplicate) {
+        this.notify.warning(
+          NOTIFY_DUPLICATE_ACCOUNT_IMPORT.message,
+          TIMEOUTS.LONG,
+        );
+        return;
+      }
+
       await importFromMnemonic(
         this.mnemonic,
         this.derivationPath,
@@ -223,9 +242,20 @@ export default class ImportAccountView extends Vue {
       this.$router.push({ name: "account" });
     } catch (error: unknown) {
       this.$logError("Import failed: " + error);
+
+      // Check if this is a duplicate account error from saveNewIdentity
+      const errorMessage =
+        error instanceof Error ? error.message : String(error);
+      if (errorMessage.includes(DUPLICATE_ACCOUNT_ERROR)) {
+        this.notify.warning(
+          NOTIFY_DUPLICATE_ACCOUNT_IMPORT.message,
+          TIMEOUTS.LONG,
+        );
+        return;
+      }
+
       this.notify.error(
-        (error instanceof Error ? error.message : String(error)) ||
-          "Failed to import account.",
+        errorMessage || "Failed to import account.",
         TIMEOUTS.LONG,
       );
     }

src/views/ImportDerivedAccountView.vue

@@ -83,6 +83,7 @@ import {
   retrieveAllAccountsMetadata,
   retrieveFullyDecryptedAccount,
   saveNewIdentity,
+  checkForDuplicateAccount,
 } from "../libs/util";
 import { logger } from "../utils/logger";
 import { Account, AccountEncrypted } from "../db/tables/accounts";
@@ -171,6 +172,16 @@ export default class ImportAccountView extends Vue {
     const newId = newIdentifier(address, publicHex, privateHex, newDerivPath);
 
     try {
+      // Check for duplicate account before creating
+      const isDuplicate = await checkForDuplicateAccount(newId.did);
+      if (isDuplicate) {
+        this.notify.warning(
+          "This derived account already exists. Please try a different derivation path.",
+          TIMEOUTS.LONG,
+        );
+        return;
+      }
+
       await saveNewIdentity(newId, mne, newDerivPath);
 
       // record that as the active DID

test-playwright/03-duplicate-import-test.spec.ts

@@ -0,0 +1,63 @@
+import { test, expect } from '@playwright/test';
+import { importUserFromAccount, getTestUserData } from './testUtils';
+import { NOTIFY_DUPLICATE_ACCOUNT_IMPORT } from '../src/constants/notifications';
+
+/**
+ * Test duplicate account import functionality
+ * 
+ * This test verifies that:
+ * 1. A user can successfully import an account the first time
+ * 2. Attempting to import the same account again shows a warning message
+ * 3. The duplicate import is prevented
+ */
+test.describe('Duplicate Account Import', () => {
+  test('should prevent importing the same account twice', async ({ page }) => {
+    const userData = getTestUserData("00");
+    
+    // First import - should succeed
+    await page.goto("./start");
+    await page.getByText("You have a seed").click();
+    await page.getByPlaceholder("Seed Phrase").fill(userData.seedPhrase);
+    await page.getByRole("button", { name: "Import" }).click();
+    
+    // Verify first import was successful
+    await expect(page.getByRole("code")).toContainText(userData.did);
+    
+    // Navigate back to start page for second import attempt
+    await page.goto("./start");
+    await page.getByText("You have a seed").click();
+    await page.getByPlaceholder("Seed Phrase").fill(userData.seedPhrase);
+    await page.getByRole("button", { name: "Import" }).click();
+    
+    // Verify duplicate import shows warning message
+    // The warning can appear either from the pre-check or from the saveNewIdentity error handling
+    await expect(page.getByText(NOTIFY_DUPLICATE_ACCOUNT_IMPORT.message)).toBeVisible();
+    
+    // Verify we're still on the import page (not redirected to account)
+    await expect(page.getByPlaceholder("Seed Phrase")).toBeVisible();
+  });
+
+  test('should allow importing different accounts', async ({ page }) => {
+    const userZeroData = getTestUserData("00");
+    const userOneData = getTestUserData("01");
+    
+    // Import first user
+    await page.goto("./start");
+    await page.getByText("You have a seed").click();
+    await page.getByPlaceholder("Seed Phrase").fill(userZeroData.seedPhrase);
+    await page.getByRole("button", { name: "Import" }).click();
+    
+    // Verify first import was successful
+    await expect(page.getByRole("code")).toContainText(userZeroData.did);
+    
+    // Navigate back to start page for second user import
+    await page.goto("./start");
+    await page.getByText("You have a seed").click();
+    await page.getByPlaceholder("Seed Phrase").fill(userOneData.seedPhrase);
+    await page.getByRole("button", { name: "Import" }).click();
+    
+    // Verify second import was successful (should not show duplicate warning)
+    await expect(page.getByRole("code")).toContainText(userOneData.did);
+    await expect(page.getByText(NOTIFY_DUPLICATE_ACCOUNT_IMPORT.message)).not.toBeVisible();
+  });
+});