Prevent duplicate accounts when not pro

app/src/main/java/org/tasks/data/OpenTaskDao.kt

@@ -28,10 +28,7 @@ class OpenTaskDao @Inject constructor(
     private val tasks = Tasks.getContentUri(authority)
     private val properties = Properties.getContentUri(authority)
 
-    suspend fun newAccounts(): List<String> =
-            getListsByAccount()
-                    .newAccounts(caldavDao)
-                    .map { it.key }
+    suspend fun newAccounts(): List<String> = getListsByAccount().newAccounts(caldavDao)
 
     suspend fun getListsByAccount(): Map<String, List<CaldavCalendar>> =
             getLists().groupBy { it.account!! }
@@ -248,6 +245,8 @@ class OpenTaskDao @Inject constructor(
 
         suspend fun Map<String, List<CaldavCalendar>>.newAccounts(caldavDao: CaldavDao) =
                 filterNot { (_, lists) -> caldavDao.anyExist(lists.map { it.url!! }) }
+                        .map { it.key }
+                        .distinct()
 
         fun Cursor.getString(columnName: String): String? =
                 getString(getColumnIndex(columnName))

app/src/main/java/org/tasks/opentasks/OpenTasksSynchronizer.kt

@@ -58,13 +58,15 @@ class OpenTasksSynchronizer @Inject constructor(
 
     suspend fun sync() {
         val lists = openTaskDao.getListsByAccount()
-        lists.newAccounts(caldavDao).forEach { (account, _) ->
-            caldavDao.insert(CaldavAccount().apply {
-                name = account.split(":")[1]
-                uuid = account
-                accountType = CaldavAccount.TYPE_OPENTASKS
-            })
-        }
+        lists.newAccounts(caldavDao)
+                .filter { caldavDao.getAccountByUuid(it) == null }
+                .forEach {
+                    caldavDao.insert(CaldavAccount().apply {
+                        name = it.split(":")[1]
+                        uuid = it
+                        accountType = CaldavAccount.TYPE_OPENTASKS
+                    })
+                }
         caldavDao.getAccounts(CaldavAccount.TYPE_OPENTASKS).forEach { account ->
             if (!lists.containsKey(account.uuid)) {
                 setError(account, context.getString(R.string.account_not_found))