support for UPC-A codes in EAN13 or EAN14 codes

Author: ajungg

CHANGELOG.md

@@ -3,6 +3,9 @@ All notable changes to this project will be documented in this file.
 
 ## [0.30.1]
 
+### Added
+- Support for UPC-A codes in EAN13 or EAN14 codes
+
 ### Changed
 - Prioritize online payment methods over offline methods if available
 - Route to entering payment method if not available

core/src/main/java/io/snabble/sdk/ProductDatabase.java

@@ -1276,15 +1276,39 @@ public Product findByCode(ScannedCode scannedCode) {
             return null;
         }
 
+        Product product = findByCode(scannedCode.getLookupCode(), scannedCode.getTemplateName());
+
+        // try again for upc codes
+        if (product == null) {
+            String upcCode = extractUpcA(scannedCode.getLookupCode());
+            if (upcCode != null) {
+                return findByCode(upcCode, scannedCode.getTemplateName());
+            }
+        }
+
+        return product;
+    }
+
+    private Product findByCode(String lookupCode, String templateName) {
         Cursor cursor = productQuery("JOIN scannableCodes s ON s.sku = p.sku " +
                 "WHERE s.code = ? AND s.template = ? LIMIT 1", new String[]{
-                scannedCode.getLookupCode(),
-                scannedCode.getTemplateName()
+                lookupCode,
+                templateName
         }, false);
 
         return getFirstProductAndClose(cursor);
     }
 
+    private String extractUpcA(String code) {
+        if (code.length() == 13 && code.startsWith("0")) {
+            return code.substring(1);
+        } else if (code.length() == 14 && code.startsWith("00")) {
+            return code.substring(2);
+        } else {
+            return null;
+        }
+    }
+
     private Product[] findBundlesOfProduct(Product product) {
         Cursor cursor = productQuery("WHERE p.bundledSku = ?", new String[]{
                 product.getSku()