Updated on 2026-08-14

domain/account/src/main/java/com/tangem/domain/account/tokens/MainAccountTokensMigration.kt

@@ -0,0 +1,23 @@
+package com.tangem.domain.account.tokens
+
+import arrow.core.Either
+import com.tangem.domain.models.account.DerivationIndex
+import com.tangem.domain.models.wallet.UserWalletId
+
+/**
+ * Interface for migrating tokens associated with a main account,
+ * but belonging to another account according to the derivation path.
+ *
+[REDACTED_AUTHOR]
+ */
+interface MainAccountTokensMigration {
+
+    /**
+     * Migration of non-native tokens from the main account to the account with the provided [derivationIndex].
+     * If there are no such tokens, the function will complete successfully.
+     *
+     * @param userWalletId The unique identifier of the user's wallet.
+     * @param derivationIndex The derivation index associated with the account.
+     */
+    suspend fun migrate(userWalletId: UserWalletId, derivationIndex: DerivationIndex): Either<Throwable, Unit>
+}

domain/account/src/main/java/com/tangem/domain/account/usecase/GetUnoccupiedAccountIndexUseCase.kt

@@ -28,7 +28,7 @@ class GetUnoccupiedAccountIndexUseCase(
     suspend operator fun invoke(userWalletId: UserWalletId): Either<Error, DerivationIndex> = either {
         val totalAccountsCount = getTotalAccountsCount(userWalletId = userWalletId)
 
-        DerivationIndex(totalAccountsCount + 1).getOrElse {
+        DerivationIndex(value = totalAccountsCount).getOrElse {
             raise(Error.InvalidDerivationIndex(it))
         }
     }