auto extract template variables on send test modal

src/Helpers/TemplateManager.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace MailCarrier\Helpers;
+
+use MailCarrier\Models\Template;
+use Twig\Environment;
+use Twig\Loader\ArrayLoader;
+use Twig\Source;
+
+class TemplateManager
+{
+    public function __construct(protected Template $template)
+    {
+        //
+    }
+
+    public static function make(Template $template): static
+    {
+        return new static($template);
+    }
+
+    public function extractVariableNames(): array
+    {
+        $source = $this->template->layout?->content . $this->template->content;
+
+        $twig = new Environment(new ArrayLoader());
+        $nodes = $twig->parse(
+            $twig->tokenize(new Source($source, ''))
+        )->getNode('body')->getNode('0');
+
+        preg_match_all("|Twig\\\Node\\\Expression\\\NameExpression\(name\: '(.*)'|mi", (string) $nodes, $matches);
+
+        return array_values(array_unique($matches[1]));
+    }
+
+    protected function getLoader(): ArrayLoader
+    {
+        $mainFileName = sprintf('main-%d.html', $this->template->id);
+        $layoutFileName = !$this->template->layout_id ? null : sprintf('layout-%d.html', $this->template->layout_id);
+        $mainFileContent = !$this->template->layout_id ? $this->template->content : sprintf(
+            '{%% extends "%s" %%}{%% block content %%}%s{%% endblock %%}',
+            $layoutFileName,
+            $this->template->content,
+        );
+
+        return new ArrayLoader([
+            $mainFileName => $mainFileContent,
+            $layoutFileName => $this->template->layout?->content,
+        ]);
+    }
+}

src/Resources/TemplateResource/Actions/SendTestAction.php

@@ -11,6 +11,7 @@
 use Illuminate\Support\HtmlString;
 use MailCarrier\Actions\SendMail;
 use MailCarrier\Dto\SendMailDto;
+use MailCarrier\Helpers\TemplateManager;
 
 class SendTestAction extends Action
 {
@@ -25,6 +26,7 @@ protected function setUp(): void
 
         $this->label('Send test');
         $this->icon('heroicon-o-paper-airplane');
+        $this->modalHeading('Send test email');
         $this->modalSubmitActionLabel('Send');
         $this->modalFooterActionsAlignment(Alignment::End);
         $this->extraAttributes([
@@ -37,7 +39,14 @@ protected function setUp(): void
                 ->required(),
             Forms\Components\KeyValue::make('variables')
                 ->keyLabel('Variable name')
-                ->valueLabel('Variable value'),
+                ->valueLabel('Variable value')
+                ->valuePlaceholder('Fill or delete')
+                ->default(
+                    Arr::mapWithKeys(
+                        TemplateManager::make($this->getRecord())->extractVariableNames(),
+                        fn (string $value) => [$value => null]
+                    )
+                ),
             Forms\Components\Checkbox::make('enqueue'),
         ]);
 

tests/Unit/TemplateManager/ExtractVariableNamesTest.php

@@ -0,0 +1,69 @@
+<?php
+
+use MailCarrier\Helpers\TemplateManager;
+use MailCarrier\Models\Layout;
+use MailCarrier\Models\Template;
+
+it('returns empty array if template has no variables', function () {
+    $template = new Template([
+        'content' => 'Hello',
+    ]);
+
+    $output = TemplateManager::make($template)->extractVariableNames();
+
+    expect($output)->toBe([]);
+});
+
+it('returns all the variables of the template', function () {
+    $template = new Template([
+        'content' => <<<'TWIG'
+            Hello {{ name }},
+            <a href="{{ ctaUrl }}">
+                Sign in
+            </a>
+
+            {% if isPremium|default(false) %}
+                {{ tierLevel|title }}
+            {% endif %}
+        TWIG,
+    ]);
+
+    $output = TemplateManager::make($template)->extractVariableNames();
+
+    expect($output)->toBe(['name', 'ctaUrl', 'isPremium', 'tierLevel']);
+});
+
+it('returns all the variables of the template along with its layout', function () {
+    $template = new Template([
+        'content' => <<<'TWIG'
+            Hello {{ name }},
+            <a href="{{ ctaUrl }}">
+                Sign in
+            </a>
+
+            {% if isPremium|default(false) %}
+                {{ tierLevel|title }}
+            {% endif %}
+        TWIG,
+    ]);
+
+    $template->setRelation('layout', new Layout([
+        'content' => <<<'TWIG'
+            <!doctype html>
+                <html lang="en">
+                <head>
+                    <meta charset="UTF-8">
+                    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+                </head>
+                <body>
+                    <h1>{{ headline }}</h1>
+                    {% block content %}{% endblock %}
+                </body>
+            </html>
+        TWIG,
+    ]));
+
+    $output = TemplateManager::make($template)->extractVariableNames();
+
+    expect($output)->toBe(['headline', 'name', 'ctaUrl', 'isPremium', 'tierLevel']);
+});