feat(main): Add configurable VIES-offline fallback policy

config.xml

@@ -2,7 +2,7 @@
 <module>
     <name>ws_vatcheck</name>
     <displayName><![CDATA[Vat Check]]></displayName>
-    <version><![CDATA[1.0.2]]></version>
+    <version><![CDATA[1.0.3]]></version>
     <description><![CDATA[Gecachte vat check]]></description>
     <author><![CDATA[Johan van der Klis | De Websmid BV]]></author>
     <tab><![CDATA[]]></tab>

config_nl.xml

@@ -2,7 +2,7 @@
 <module>
     <name>ws_vatcheck</name>
     <displayName><![CDATA[Vat Check]]></displayName>
-    <version><![CDATA[1.0.1]]></version>
+    <version><![CDATA[1.0.3]]></version>
     <description><![CDATA[Gecachte vat check]]></description>
     <author><![CDATA[Johan van der Klis | De Websmid BV]]></author>
     <tab><![CDATA[]]></tab>

src/Adapter/EuValidatorAdapter.php

@@ -8,6 +8,7 @@ use PH7\Eu\Vat\Exception;
 use Websmid\VatCheck\Config\Config;
 use Websmid\VatCheck\Model\VatCache;
 use PrestaShopLogger;
+use Configuration;
 
 class EuValidatorAdapter
 {   
@@ -38,7 +39,7 @@ class EuValidatorAdapter
                 3
             );
 
-            return false;
+            return $this->resolveOfflineFallback();
         }
 
         if( $euVatValidator instanceof Validator ){
@@ -52,4 +53,50 @@ class EuValidatorAdapter
 
         return true;
     }
+
+    /**
+     * Decide what to do when VIES itself can't be reached, per the configured
+     * Config::OFFLINE_MODE_CONFIG_KEY policy. Returning true here tells
+     * CacheTaxManager to go ahead and read VatCache::checkVatIsValid() next, so
+     * the "reuse last known" modes just need to confirm a prior record exists
+     * (checkVatIsValid() will then return whatever it already holds); the
+     * "always valid" modes without a prior record need us to actually write one.
+     */
+    private function resolveOfflineFallback(): bool
+    {
+        $mode = Configuration::get(Config::OFFLINE_MODE_CONFIG_KEY) ?: Config::OFFLINE_MODE_DEFAULT;
+        $fullVat = $this->isoCode.$this->vatNr;
+
+        switch ($mode) {
+            case Config::OFFLINE_MODE_VALID:
+                $this->storeOfflineResult($fullVat, true);
+
+                return true;
+
+            case Config::OFFLINE_MODE_LAST_KNOWN_OR_INVALID:
+                return VatCache::hasEverBeenChecked($fullVat);
+
+            case Config::OFFLINE_MODE_LAST_KNOWN_OR_VALID:
+                if (VatCache::hasEverBeenChecked($fullVat)) {
+                    return true;
+                }
+
+                $this->storeOfflineResult($fullVat, true);
+
+                return true;
+
+            case Config::OFFLINE_MODE_INVALID:
+            default:
+                return false;
+        }
+    }
+
+    private function storeOfflineResult(string $fullVat, bool $valid): void
+    {
+        $vatCache = VatCache::getOrCreateByVat($fullVat);
+        $vatCache->vat_nr = $fullVat;
+        $vatCache->valid = $valid;
+
+        $vatCache->save();
+    }
 }

src/Config/Config.php

@@ -14,6 +14,24 @@ class Config
 
 	CONST CACHE_VALIDITY = 1;
 
+	// Configuration key holding the chosen offline-fallback mode.
+	CONST OFFLINE_MODE_CONFIG_KEY = 'WS_VATCHECK_OFFLINE_MODE';
+
+	// What to decide when the VIES service can't be reached.
+	CONST OFFLINE_MODE_INVALID = 'invalid';
+	CONST OFFLINE_MODE_VALID = 'valid';
+	CONST OFFLINE_MODE_LAST_KNOWN_OR_INVALID = 'last_known_or_invalid';
+	CONST OFFLINE_MODE_LAST_KNOWN_OR_VALID = 'last_known_or_valid';
+
+	CONST OFFLINE_MODE_DEFAULT = self::OFFLINE_MODE_INVALID;
+
+	CONST OFFLINE_MODE_LABELS = [
+		self::OFFLINE_MODE_INVALID => 'Always mark VAT as invalid',
+		self::OFFLINE_MODE_VALID => 'Always mark VAT as valid',
+		self::OFFLINE_MODE_LAST_KNOWN_OR_INVALID => 'Reuse the last known result, otherwise mark invalid',
+		self::OFFLINE_MODE_LAST_KNOWN_OR_VALID => 'Reuse the last known result, otherwise mark valid',
+	];
+
 	// Article 39bis W.BTW intra-community exemption notice, per invoice language.
 	CONST INTRACOMMUNITY_EXEMPTION_TEXTS = [
 		'nl' => 'Vrijgestelde intracommunautaire levering – artikel 39bis W.BTW',

src/Model/VatCache.php

@@ -45,6 +45,16 @@ class VatCache extends ObjectModel
         return (bool)Db::getInstance()->getValue('SELECT `valid` FROM `'._DB_PREFIX_.'vat_cache` WHERE `vat_nr` = "'.pSQL($vatNr).'" ORDER BY `id_vat` DESC');
     }
 
+    /**
+     * Unlike checkVatIsCached(), this ignores Config::CACHE_VALIDITY entirely —
+     * used by the offline-fallback "reuse last known result" modes, which want
+     * whatever was last recorded regardless of how stale it is.
+     */
+    public static function hasEverBeenChecked(string $vatNr)
+    {
+        return (bool)Db::getInstance()->getValue('SELECT `id_vat` FROM `'._DB_PREFIX_.'vat_cache` WHERE `vat_nr` = "'.pSQL($vatNr).'" ORDER BY `id_vat` DESC');
+    }
+
     public static function getOrCreateByVat(string $vatNr)
     {
         $className = get_called_class();

src/Module/Admin/SettingsForm.php

@@ -0,0 +1,109 @@
+<?php
+
+namespace Websmid\VatCheck\Module\Admin;
+
+use Websmid\VatCheck\Config\Config;
+use Configuration;
+use Tools;
+use HelperForm;
+use Context;
+
+trait SettingsForm
+{
+    public function getContent()
+    {
+        if ((bool) Tools::isSubmit('submitWsVatCheckSettings')) {
+            $this->postProcessSettings();
+        }
+
+        return $this->renderSettingsForm();
+    }
+
+    private function postProcessSettings()
+    {
+        $mode = Tools::getValue(Config::OFFLINE_MODE_CONFIG_KEY);
+
+        if (!array_key_exists($mode, Config::OFFLINE_MODE_LABELS)) {
+            return;
+        }
+
+        Configuration::updateValue(Config::OFFLINE_MODE_CONFIG_KEY, $mode);
+    }
+
+    private function renderSettingsForm()
+    {
+        $helper = new HelperForm();
+
+        $helper->show_toolbar = false;
+        $helper->table = $this->table;
+        $helper->module = $this;
+        $helper->default_form_language = Context::getContext()->language->id;
+        $helper->allow_employee_form_lang = (int) Configuration::get('PS_BO_ALLOW_EMPLOYEE_FORM_LANG', 0);
+
+        $helper->identifier = $this->identifier;
+        $helper->submit_action = 'submitWsVatCheckSettings';
+        $helper->currentIndex = Context::getContext()->link->getAdminLink('AdminModules', false)
+            . '&configure=' . $this->name
+            . '&tab_module=' . $this->tab
+            . '&module_name=' . $this->name;
+        $helper->token = Tools::getAdminTokenLite('AdminModules');
+
+        $helper->tpl_vars = [
+            'fields_value' => $this->getSettingsFormValues(),
+            'languages' => Context::getContext()->controller->getLanguages(),
+            'id_language' => Context::getContext()->language->id,
+        ];
+
+        return $helper->generateForm([$this->getSettingsFormStructure()]);
+    }
+
+    private function getSettingsFormValues()
+    {
+        return [
+            Config::OFFLINE_MODE_CONFIG_KEY => Configuration::get(
+                Config::OFFLINE_MODE_CONFIG_KEY,
+                null,
+                null,
+                null,
+                Config::OFFLINE_MODE_DEFAULT
+            ),
+        ];
+    }
+
+    private function getSettingsFormStructure()
+    {
+        $choices = [];
+        foreach (Config::OFFLINE_MODE_LABELS as $value => $label) {
+            $choices[] = [
+                'id' => $value,
+                'value' => $value,
+                'label' => $this->trans($label, [], 'Modules.Ws_VatCheck.Admin'),
+            ];
+        }
+
+        return [
+            'form' => [
+                'legend' => [
+                    'title' => $this->trans('VAT Check settings', [], 'Modules.Ws_VatCheck.Admin'),
+                    'icon' => 'icon-cogs',
+                ],
+                'input' => [
+                    [
+                        'type' => 'radio',
+                        'label' => $this->trans('When VIES is unreachable', [], 'Modules.Ws_VatCheck.Admin'),
+                        'name' => Config::OFFLINE_MODE_CONFIG_KEY,
+                        'desc' => $this->trans(
+                            'What to decide about a VAT number when the EU VIES service can\'t be reached to check it.',
+                            [],
+                            'Modules.Ws_VatCheck.Admin'
+                        ),
+                        'values' => $choices,
+                    ],
+                ],
+                'submit' => [
+                    'title' => $this->trans('Save', [], 'Admin.Actions'),
+                ],
+            ],
+        ];
+    }
+}

src/Module/Install.php

@@ -4,6 +4,7 @@ namespace Websmid\VatCheck\Module;
 
 use Websmid\VatCheck\Config\Config;
 use Db;
+use Configuration;
 
 trait Install
 {
@@ -21,9 +22,18 @@ trait Install
             return false;
         }
 
+        if (!$this->registerConfiguration()) {
+            return false;
+        }
+
         return true;
     }
 
+    private function registerConfiguration()
+    {
+        return Configuration::updateValue(Config::OFFLINE_MODE_CONFIG_KEY, Config::OFFLINE_MODE_DEFAULT);
+    }
+
     private function registerHooks()
     {
         foreach (Config::HOOKS as $hook) {

upgrade/upgrade-1.0.3.php

@@ -0,0 +1,12 @@
+<?php
+
+use Websmid\VatCheck\Config\Config;
+
+if (!defined('_PS_VERSION_')) {
+    exit;
+}
+
+function upgrade_module_1_0_3($module)
+{
+    return Configuration::updateValue(Config::OFFLINE_MODE_CONFIG_KEY, Config::OFFLINE_MODE_DEFAULT);
+}

ws_vatcheck.php

@@ -23,6 +23,7 @@
 use Websmid\VatCheck\Module\Install;
 use Websmid\VatCheck\Module\Front\FrontHooks;
 use Websmid\VatCheck\Module\Admin\AdminHooks;
+use Websmid\VatCheck\Module\Admin\SettingsForm;
 
 if (file_exists(__DIR__ . '/vendor/autoload.php')) {
     require_once __DIR__ . '/vendor/autoload.php';
@@ -35,12 +36,13 @@ class Ws_VatCheck extends \Module
 {
     use Install;
     use AdminHooks;
+    use SettingsForm;
     use FrontHooks;
 
     public function __construct()
     {
         $this->name = 'ws_vatcheck';
-        $this->version = '1.0.2';
+        $this->version = '1.0.3';
         $this->author = 'Johan van der Klis | De Websmid BV';
         $this->need_instance = 0;
         $this->bootstrap = true;