From ea34130b09557558f6d08430020be15e0165acaa Mon Sep 17 00:00:00 2001
From: Herant <maxed1@gmail.com>
Date: Wed, 13 Oct 2021 16:03:20 +0200
Subject: [PATCH 1/3] Implement logic for retrieving first page if pagination
 yields no result after filtering

---
 .../Catalog/Layer/ItemCollectionProvider.php  | 11 +++++++-
 Model/Catalog/Layer/NavigationContext.php     | 28 +++++++++++++++++--
 .../Url/Strategy/QueryParameterStrategy.php   |  3 +-
 3 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/Model/Catalog/Layer/ItemCollectionProvider.php b/Model/Catalog/Layer/ItemCollectionProvider.php
index 47c7c0fb..8d9f5a5b 100644
--- a/Model/Catalog/Layer/ItemCollectionProvider.php
+++ b/Model/Catalog/Layer/ItemCollectionProvider.php
@@ -75,7 +75,16 @@ public function getCollection(Category $category)
         }
 
         try {
-            return $this->collectionFactory->create(['navigationContext' => $this->navigationContext]);
+            /** @var Collection $collection */
+            $collection = $this->collectionFactory->create(['navigationContext' => $this->navigationContext]);
+
+            if (count($collection->getItems()) < 1) {
+                $collection = $this->collectionFactory
+                    ->create(['navigationContext' => $this->navigationContext->resetPagination()])
+                ;
+            }
+
+            return $collection;
         } catch (TweakwiseException $e) {
             $this->log->critical($e);
             $this->config->setTweakwiseExceptionThrown();
diff --git a/Model/Catalog/Layer/NavigationContext.php b/Model/Catalog/Layer/NavigationContext.php
index 6abd5176..0ac97161 100644
--- a/Model/Catalog/Layer/NavigationContext.php
+++ b/Model/Catalog/Layer/NavigationContext.php
@@ -36,7 +36,7 @@ class NavigationContext
     /**
      * @var ProductNavigationRequest
      */
-    protected $request;
+    protected $request = null;
 
     /**
      * @var RequestFactory
@@ -49,9 +49,9 @@ class NavigationContext
     protected $client;
 
     /**
-     * @var ProductNavigationResponse
+     * @var ProductNavigationResponse|null
      */
-    protected $response;
+    protected $response = null;
 
     /**
      * @var Url
@@ -150,6 +150,7 @@ public function getResponse(): ProductNavigationResponse
     {
         if (!$this->response) {
             $request = $this->getRequest();
+
             $this->initializeRequest($request);
 
             $this->response = $this->client->request($request);
@@ -168,6 +169,27 @@ public function hasResponse(): bool
         return $this->response !== null;
     }
 
+    /**
+     * @return $this
+     */
+    public function resetPagination(): self
+    {
+        $params = $this->request->getParameters();
+        unset($params['tn_p']);
+        unset($params['tn_fk_p']);
+        $params['resetPagination'] = true;
+        $params['tn_fk_p'] = 1;
+        $params['tn_p'] = 1;
+
+        $this->request = null;
+
+        $request = $this->getRequest()->setParameters($params);
+
+        $this->response = null;
+
+        return $this->initializeRequest($request);
+    }
+
     /**
      * @param $attributeCodes
      * @return Attribute[]
diff --git a/Model/Catalog/Layer/Url/Strategy/QueryParameterStrategy.php b/Model/Catalog/Layer/Url/Strategy/QueryParameterStrategy.php
index 5daa4f4d..4e433acc 100644
--- a/Model/Catalog/Layer/Url/Strategy/QueryParameterStrategy.php
+++ b/Model/Catalog/Layer/Url/Strategy/QueryParameterStrategy.php
@@ -345,7 +345,8 @@ public function apply(MagentoHttpRequest $request, ProductNavigationRequest $nav
         }
 
         $page = $this->getPage($request);
-        if ($page) {
+
+        if ($page && (bool) $navigationRequest->getParameter('resetPagination') === false) {
             $navigationRequest->setPage($page);
         }
 

From ca836fa0e5be07ce47ba105d193268820215f026 Mon Sep 17 00:00:00 2001
From: Herant <maxed1@gmail.com>
Date: Wed, 13 Oct 2021 16:04:16 +0200
Subject: [PATCH 2/3] Implement logic for retrieving first page if pagination
 yields no result after filtering

---
 Model/Catalog/Layer/ItemCollectionProvider.php | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Model/Catalog/Layer/ItemCollectionProvider.php b/Model/Catalog/Layer/ItemCollectionProvider.php
index 8d9f5a5b..f2d3915e 100644
--- a/Model/Catalog/Layer/ItemCollectionProvider.php
+++ b/Model/Catalog/Layer/ItemCollectionProvider.php
@@ -75,7 +75,6 @@ public function getCollection(Category $category)
         }
 
         try {
-            /** @var Collection $collection */
             $collection = $this->collectionFactory->create(['navigationContext' => $this->navigationContext]);
 
             if (count($collection->getItems()) < 1) {

From ec0fd7ad804d71c8ff73c971819bec26539e29ed Mon Sep 17 00:00:00 2001
From: Herant <maxed1@gmail.com>
Date: Fri, 15 Oct 2021 11:27:40 +0200
Subject: [PATCH 3/3] Update tweakwise pagination param values when reset
 pagination is requested

---
 Model/Catalog/Layer/NavigationContext.php | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Model/Catalog/Layer/NavigationContext.php b/Model/Catalog/Layer/NavigationContext.php
index 0ac97161..61dacc6f 100644
--- a/Model/Catalog/Layer/NavigationContext.php
+++ b/Model/Catalog/Layer/NavigationContext.php
@@ -175,8 +175,6 @@ public function hasResponse(): bool
     public function resetPagination(): self
     {
         $params = $this->request->getParameters();
-        unset($params['tn_p']);
-        unset($params['tn_fk_p']);
         $params['resetPagination'] = true;
         $params['tn_fk_p'] = 1;
         $params['tn_p'] = 1;