Use pages map

composer.json

@@ -20,6 +20,7 @@
         "erusev/parsedown": "^1.7",
         "erusev/parsedown-extra": "^0.8.1",
         "symfony/asset": "^4.4|^5.1",
+        "symfony/expression-language": "^4.4|^5.1",
         "symfony/framework-bundle": "^4.4|^5.1",
         "symfony/http-kernel": "^4.4|^5.1",
         "symfony/routing": "^4.4|^5.1",

spec/Helper/PageHelperSpec.php

@@ -3,39 +3,38 @@
 namespace spec\Mobizel\Bundle\MarkdownDocsBundle\Helper;
 
 use Mobizel\Bundle\MarkdownDocsBundle\Helper\PageHelper;
-use Mobizel\Bundle\MarkdownDocsBundle\Template\TemplateHandlerInterface;
 use PhpSpec\ObjectBehavior;
 
 class PageHelperSpec extends ObjectBehavior
 {
-    function let(TemplateHandlerInterface $templateHandler): void
+    function let(): void
     {
-        $this->beConstructedWith($templateHandler);
+        $this->beConstructedWith([
+            'first-page' => 'First page',
+            'foo' => 'Foo fighters',
+            'last-page' => 'Last page',
+        ]);
     }
 
     function it_is_initializable(): void
     {
         $this->shouldHaveType(PageHelper::class);
     }
 
-    function it_can_get_page_title(TemplateHandlerInterface $templateHandler): void
+    function it_can_get_page_title(): void
     {
-        $templateHandler->getTemplateAbsolutePath('foo')->willReturn('tests/docs/foo.md');
-
         $this->getTitle('foo')->shouldReturn('Foo fighters');
     }
 
-    function it_return_default_title_when_no_title_has_been_found(TemplateHandlerInterface $templateHandler): void
+    function it_can_get_previous_page(): void
     {
-        $templateHandler->getTemplateAbsolutePath('bar')->willReturn('tests/docs/bar.md');
-
-        $this->getTitle('bar')->shouldReturn('Bar');
+        $this->getPreviousPage('foo')->shouldReturn('first-page');
+        $this->getPreviousPage('first-page')->shouldReturn(null);
     }
 
-    function it_return_default_title_when_file_is_empty(TemplateHandlerInterface $templateHandler): void
+    function it_can_get_next_page(): void
     {
-        $templateHandler->getTemplateAbsolutePath('empty')->willReturn('tests/docs/empty.md');
-
-        $this->getTitle('empty')->shouldReturn('Empty');
+        $this->getNextPage('foo')->shouldReturn('last-page');
+        $this->getNextPage('last-page')->shouldReturn(null);
     }
 }

src/Controller/PageAction.php

@@ -23,8 +23,9 @@ final class PageAction extends AbstractController
     /** @var PageItemDataProvider */
     private $pageItemDataProvider;
 
-    public function __construct(PageItemDataProvider $pageItemDataProvider)
-    {
+    public function __construct(
+        PageItemDataProvider $pageItemDataProvider
+    ) {
         $this->pageItemDataProvider = $pageItemDataProvider;
     }
 

src/DataProvider/PageCollectionDataProvider.php

@@ -29,6 +29,29 @@ public function __construct(string $docsDir)
         $this->docsDir = $docsDir;
     }
 
+    public function getPagesMap(): array
+    {
+        $finder = new Finder();
+
+        $finder
+            ->files()
+            ->in($this->docsDir)
+            //->depth(0)
+            ->sort(PageSorter::sortByTitle());
+        $pages = [];
+
+        foreach ($finder as $file) {
+            $pageInfo = new PageInfo($file->getPathname(), $file->getRelativePath(), $file->getRelativePathname());
+
+            /** @var string $slug */
+            $slug = preg_replace('/\.md$/', '', $pageInfo->getRelativePathName());
+
+            $pages[$slug] = $pageInfo->getTitle();
+        }
+
+        return $pages;
+    }
+
     public function getRootPages(): iterable
     {
         $finder = new Finder();

src/DataProvider/PageCollectionDataProviderInterface.php

@@ -15,6 +15,8 @@
 
 interface PageCollectionDataProviderInterface
 {
+    public function getPagesMap(): array;
+
     public function getRootPages(): iterable;
 
     public function getChildrenPages(string $parentSlug): iterable;

src/Helper/PageHelper.php

@@ -13,24 +13,51 @@
 
 namespace Mobizel\Bundle\MarkdownDocsBundle\Helper;
 
-use Mobizel\Bundle\MarkdownDocsBundle\Page\PageInfo;
-use Mobizel\Bundle\MarkdownDocsBundle\Template\TemplateHandlerInterface;
+use Webmozart\Assert\Assert;
 
 final class PageHelper implements PageHelperInterface
 {
-    /** @var TemplateHandlerInterface */
-    private $templateHandler;
+    /** @var array */
+    private $pagesMap;
 
-    public function __construct(TemplateHandlerInterface $templateHandler)
+    public function __construct(array $pagesMap)
     {
-        $this->templateHandler = $templateHandler;
+        $this->pagesMap = $pagesMap;
     }
 
     public function getTitle(string $slug): string
     {
-        $path = $this->templateHandler->getTemplateAbsolutePath($slug);
-        $page = new PageInfo($path, '', '');
+        return $this->pagesMap[$slug] ?? '';
+    }
+
+    public function getPreviousPage(string $slug): ?string
+    {
+        $currentPosition = $this->getCurrentPosition($slug);
+
+        return $this->getPageFromPosition($currentPosition - 1);
+    }
+
+    public function getNextPage(string $slug): ?string
+    {
+        $currentPosition = $this->getCurrentPosition($slug);
+
+        return $this->getPageFromPosition($currentPosition + 1);
+    }
+
+    private function getCurrentPosition(string $slug): int
+    {
+        /** @var int $currentPosition */
+        $currentPosition = array_search($slug, array_keys($this->pagesMap));
+        Assert::notFalse($currentPosition, 'Current position was not found');
+
+        return $currentPosition;
+    }
+
+    private function getPageFromPosition(int $position): ?string
+    {
+        /** @var string|null $slug */
+        $slug = array_keys($this->pagesMap)[$position] ?? null;
 
-        return $page->getTitle();
+        return $slug;
     }
 }

src/Helper/PageHelperInterface.php

@@ -16,4 +16,8 @@
 interface PageHelperInterface
 {
     public function getTitle(string $slug): string;
+
+    public function getPreviousPage(string $slug): ?string;
+
+    public function getNextPage(string $slug): ?string;
 }

src/Resources/config/services.xml

@@ -3,7 +3,6 @@
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
         https://symfony.com/schema/dic/services/services-1.0.xsd">
-
     <services>
         <defaults autowire="false" autoconfigure="true" public="true"/>
 
@@ -17,7 +16,7 @@
         <service id="Mobizel\Bundle\MarkdownDocsBundle\Template\TemplateHandlerInterface" alias="mobizel_markdown_docs.template.template_handler"/>
 
         <service id="mobizel_markdown_docs.helper.page_helper" class="Mobizel\Bundle\MarkdownDocsBundle\Helper\PageHelper">
-            <argument key="$templateHandler" type="service" id="mobizel_markdown_docs.template.template_handler"/>
+            <argument key="$pagesMap" type="expression">service('mobizel_markdown_docs.data_provider.page_collection').getPagesMap()</argument>
         </service>
 
         <!-- Data Providers -->
@@ -39,6 +38,10 @@
         </service>
         <service id="Mobizel\Bundle\MarkdownDocsBundle\Twig\Extension\PageTitleExtensionInterface" alias="mobizel_markdown_docs.twig.extension.page_title"/>
 
+        <service id="mobizel_markdown_docs.twig.extension.pagination" class="Mobizel\Bundle\MarkdownDocsBundle\Twig\Extension\PaginationExtension">
+            <argument key="$pageHelper" type="service" id="mobizel_markdown_docs.helper.page_helper"/>
+        </service>
+        <service id="Mobizel\Bundle\MarkdownDocsBundle\Twig\Extension\PaginationExtensionInterface" alias="mobizel_markdown_docs.twig.extension.pagination"/>
 
         <!-- Controllers -->
 

src/Twig/Extension/PaginationExtension.php

@@ -0,0 +1,47 @@
+<?php
+
+/*
+ * This file is part of the Mobizel package.
+ *
+ * (c) Mobizel
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Mobizel\Bundle\MarkdownDocsBundle\Twig\Extension;
+
+use Mobizel\Bundle\MarkdownDocsBundle\Helper\PageHelperInterface;
+use Twig\Extension\AbstractExtension;
+use Twig\TwigFunction;
+
+final class PaginationExtension extends AbstractExtension implements PaginationExtensionInterface
+{
+    /** @var PageHelperInterface */
+    private $pageHelper;
+
+    public function __construct(PageHelperInterface $pageHelper)
+    {
+        $this->pageHelper = $pageHelper;
+    }
+
+    public function getFunctions()
+    {
+        return [
+            new TwigFunction('previous_page', [$this, 'previousPage']),
+            new TwigFunction('next_page', [$this, 'nextPage']),
+        ];
+    }
+
+    public function previousPage(string $slug): ?string
+    {
+        return $this->pageHelper->getPreviousPage($slug);
+    }
+
+    public function nextPage(string $slug): ?string
+    {
+        return $this->pageHelper->getNextPage($slug);
+    }
+}

src/Twig/Extension/PaginationExtensionInterface.php

@@ -0,0 +1,21 @@
+<?php
+
+/*
+ * This file is part of the Mobizel package.
+ *
+ * (c) Mobizel
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Mobizel\Bundle\MarkdownDocsBundle\Twig\Extension;
+
+interface PaginationExtensionInterface
+{
+    public function previousPage(string $slug): ?string;
+
+    public function nextPage(string $slug): ?string;
+}