Fix: update tin validation

Author: cpa-coder

DebitExpress.VatRelief/Utils/Extensions.cs

@@ -93,13 +93,6 @@ public static bool IsTrue(this string? str)
         return upper is "YES" or "Y" or "TRUE" or "T" or "1";
     }
 
-    public static bool IsValidTin(this string? str)
-    {
-        if (string.IsNullOrEmpty(str)) return false;
-
-        return new Regex("^[0-9]\\d{2}-[0-9]\\d{2}-[0-9]\\d{2}-[0-9]\\d{2,4}$").IsMatch(str);
-    }
-
     public static string QuarterRangeString(int startingMonth, int year)
     {
         var startingDate = GetEndOfMonth(year, startingMonth);

DebitExpress.VatRelief/Utils/VatTemplateReader.cs

@@ -41,7 +41,7 @@ private Result<ExcelData> ReadInternal(string path)
             var workbook = new XLWorkbook(path);
             var info = GetInfo(workbook);
             var sales = GetSalesData(workbook);
-            var purchases = GetPurchaseData(workbook);
+            var purchases = GetPurchaseData(workbook, info);
 
             return new Result<ExcelData>(new ExcelData(info, sales, purchases));
         }
@@ -168,7 +168,7 @@ private static Sales ParseSalesLineItem(IXLRow row, int i)
         };
     }
 
-    private static List<Purchases> GetPurchaseData(IXLWorkbook workbook)
+    private static List<Purchases> GetPurchaseData(IXLWorkbook workbook, Info info)
     {
         var purchaseSheet = workbook.Worksheet("PURCHASES");
         if (purchaseSheet == null) throw new ArgumentException("PURCHASES sheet not found");
@@ -178,7 +178,12 @@ private static List<Purchases> GetPurchaseData(IXLWorkbook workbook)
         for (var i = 2; i <= rowCount; i++)
         {
             var row = purchaseSheet.Row(i);
-            purchases.Add(ParsePurchasesLineItem(row, i));
+            var purchase = ParsePurchasesLineItem(row, i);
+            
+            if (purchase.Tin.Strip() == info.Tin)
+                throw new ArgumentException($"TIN in PURCHASES sheet cell B{i} cannot be the same as the TIN of the taxpayer");
+
+            purchases.Add(purchase);
         }
 
         return purchases;