From 3cad498363503bf463ff2e87d37858ac00614df2 Mon Sep 17 00:00:00 2001
From: niels <niels@eleshop.nl>
Date: Tue, 18 Feb 2025 16:03:36 +0100
Subject: [PATCH] Add checksum to CY validator

---
 src/Vies/Validator/ValidatorCY.php       | 29 ++++++++++++++++++++++--
 tests/Vies/Validator/ValidatorCYTest.php |  2 ++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/Vies/Validator/ValidatorCY.php b/src/Vies/Validator/ValidatorCY.php
index 3cdd866..d05658a 100644
--- a/src/Vies/Validator/ValidatorCY.php
+++ b/src/Vies/Validator/ValidatorCY.php
@@ -41,7 +41,32 @@ public function validate(string $vatNumber): bool
             return false;
         }
 
-        return in_array((int) $vatNumber[0], [0, 1, 3, 4, 5, 6, 9], true)
-            && ctype_alpha($vatNumber[8]);
+        $total = 0;
+        for ($i = 0; $i < 8; ++$i) {
+            $temp = (int) $vatNumber[$i];
+            if (0 === $i % 2) {
+                if (0 === $temp) {
+                    $temp = 1;
+                } elseif (1 === $temp) {
+                    $temp = 0;
+                } elseif (2 === $temp) {
+                    $temp = 5;
+                } elseif (3 === $temp) {
+                    $temp = 7;
+                } elseif (4 === $temp) {
+                    $temp = 9;
+                } else {
+                    $temp = 2 * $temp + 3;
+                }
+            }
+            $total += $temp;
+        }
+
+        // Establish check digit using modulus 26, and translate to char. equivalent.
+        $total = $total % 26;
+        $total = chr($total + 65);
+
+        // Check to see if the check digit given is correct
+        return $vatNumber[8] === $total;
     }
 }
diff --git a/tests/Vies/Validator/ValidatorCYTest.php b/tests/Vies/Validator/ValidatorCYTest.php
index 0c536f9..47616f1 100644
--- a/tests/Vies/Validator/ValidatorCYTest.php
+++ b/tests/Vies/Validator/ValidatorCYTest.php
@@ -18,6 +18,8 @@ public function testValidator(string $vatNumber, bool $state)
     public function vatNumberProvider()
     {
         return [
+            ['60040893B', true],
+            ['60052853Y', true],
             ['00532445O', true],
             ['005324451', false],
             ['0053244511', false],