CRM-19585, fixed code to get previous financial item details

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* CRM-19585: Sales tax issue
  https://issues.civicrm.org/jira/browse/CRM-19585

CRM/Financial/BAO/FinancialItem.php

@@ -295,13 +295,28 @@ public static function checkContactPresent($contactIds, &$error) {
    * @return object CRM_Core_DAO
    */
   public static function getPreviousFinancialItem($entityId, $entityTable = 'civicrm_line_item') {
+    $liabilityAccountType = CRM_Core_OptionGroup::getValue('financial_account_type', 'Liability', 'name');
     $queryParams = array(
       1 => array($entityId, 'Integer'),
       2 => array($entityTable, 'String'),
+      3 => array($liabilityAccountType, 'Integer'),
     );
-    $query = 'SELECT id, description, status_id, financial_account_id 
-      FROM civicrm_financial_item
-      WHERE entity_id = %1 AND entity_table = %2 ORDER BY id DESC LIMIT 1';
+    $query = 'SELECT cfi.id, cfi.description, cfi.amount, cfi.financial_account_id, cfi.status_id
+      FROM `civicrm_financial_item` cfi
+        INNER JOIN civicrm_entity_financial_trxn ceft 
+          ON ceft.entity_id = cfi.id AND ceft.entity_table = "civicrm_financial_item"
+        INNER JOIN civicrm_financial_trxn cft ON cft.id = ceft.financial_trxn_id
+        INNER JOIN civicrm_financial_account cfa ON cfa.id = cfi.financial_account_id
+      WHERE cfi.entity_table = %2 AND cfi.entity_id = %1 AND 
+        CASE 
+          WHEN cfa.financial_account_type_id = %3
+            AND cfi.financial_account_id  = from_financial_account_id
+          THEN 1
+          WHEN cfa.financial_account_type_id = %3
+          THEN 0
+          ELSE 1
+        END
+      GROUP BY cfi.id ORDER BY cfi.id DESC LIMIT 1';
     $prevFinancialItem = CRM_Core_DAO::executeQuery($query, $queryParams);
     $prevFinancialItem->fetch();
     return $prevFinancialItem;