Create invisible duplicate submit button if more than one `submitElem…

…ents` is present

asset/css/primary-submit-btn-duplicate.less

@@ -0,0 +1,16 @@
+/**
+  Automatically set CSS class for duplicated submit buttons
+  used for implicit form submission that should be invisible
+  and not take up any space. `display: none` is not an option,
+  because at least Safari will then ignore the element completely
+  when submitting a form.
+ */
+.primary-submit-btn-duplicate {
+  border: 0;
+  height: 0;
+  margin: 0;
+  padding: 0;
+  visibility: hidden;
+  width: 0;
+  position: absolute;
+}

src/Compat/CompatForm.php

@@ -2,7 +2,11 @@
 
 namespace ipl\Web\Compat;
 
+use ipl\Html\Contract\FormSubmitElement;
 use ipl\Html\Form;
+use ipl\Html\FormElement\SubmitElement;
+use ipl\Html\HtmlDocument;
+use ipl\Html\HtmlString;
 use ipl\I18n\Translation;
 use ipl\Web\FormDecorator\IcingaFormDecorator;
 
@@ -12,6 +16,27 @@ class CompatForm extends Form
 
     protected $defaultAttributes = ['class' => 'icinga-form icinga-controls'];
 
+    /**
+     * Render the content of the element to HTML
+     *
+     * A duplicate of the primary submit button is being prepended if there is more than one present.
+     *
+     * @return string
+     */
+    public function renderContent(): string
+    {
+        if (count($this->submitElements) > 1) {
+            return (new HtmlDocument())
+                ->setHtmlContent(
+                    $this->duplicateSubmitButton($this->submitButton),
+                    new HtmlString(parent::renderContent())
+                )
+                ->render();
+        }
+
+        return parent::renderContent();
+    }
+
     public function hasDefaultElementDecorator()
     {
         if (parent::hasDefaultElementDecorator()) {
@@ -22,4 +47,28 @@ public function hasDefaultElementDecorator()
 
         return true;
     }
+
+    /**
+     * Return a duplicate of the given submit button with the `class` attribute fixed to `primary-submit-btn-duplicate`
+     *
+     * @param FormSubmitElement $originalSubmitButton
+     *
+     * @return SubmitElement
+     */
+    public function duplicateSubmitButton(FormSubmitElement $originalSubmitButton): SubmitElement
+    {
+        $attributes = array_reduce(
+            $originalSubmitButton->getAttributes()->getIterator()->getArrayCopy(),
+            function ($accumulator, $attribute) {
+                $accumulator[$attribute->getName()] = $attribute->getValue();
+            },
+            []
+        );
+        $attributes['class'] = 'primary-submit-btn-duplicate';
+
+        $submit = (new SubmitElement($originalSubmitButton->getName(), $attributes))
+            ->setValue($originalSubmitButton->getValue());
+
+        return $submit;
+    }
 }

tests/Compat/CompatFormTest.php

@@ -0,0 +1,92 @@
+<?php
+
+namespace ipl\Tests\Web\Compat;
+
+use ipl\Html\FormElement\SubmitElement;
+use ipl\Tests\Html\TestCase;
+use ipl\Web\Compat\CompatForm;
+
+class CompatFormTest extends TestCase
+{
+    /** @var CompatForm */
+    private $form;
+
+    protected function setUp(): void
+    {
+        $this->form = new CompatForm();
+    }
+
+    public function testDuplicateSubmitButtonApplied(): void
+    {
+        $this->form->addElement('submit', 'submitCreate');
+        $this->form->addElement('submit', 'submitDelete');
+
+        $expected = <<<'HTML'
+    <form class="icinga-form icinga-controls" method="POST">
+      <input class="primary-submit-btn-duplicate" name="submitCreate" type="submit" value="submitCreate"/>
+      <div class="control-group form-controls">
+        <input class="btn-primary" name="submitCreate" type="submit" value="submitCreate"/>
+      </div>
+      <div class="control-group form-controls">
+        <input class="btn-primary" name="submitDelete" type="submit" value="submitDelete"/>
+      </div>
+    </form>
+HTML;
+
+        $this->assertHtml($expected, $this->form);
+    }
+
+    public function testDuplicateSubmitButtonOmitted(): void
+    {
+        $this->form->addElement('submit', 'submitCreate');
+
+        $expected = <<<'HTML'
+    <form class="icinga-form icinga-controls" method="POST">
+      <div class="control-group form-controls">
+        <input class="btn-primary" name="submitCreate" type="submit" value="submitCreate"/>
+      </div>
+    </form>
+HTML;
+
+        $this->assertHtml($expected, $this->form);
+    }
+
+    public function testDuplicateSubmitButtonAddedOnlyOnce(): void
+    {
+        $this->form->addElement('submit', 'submitCreate');
+        $this->form->addElement('submit', 'submitDelete');
+
+        $expected = <<<'HTML'
+    <form class="icinga-form icinga-controls" method="POST">
+      <input class="primary-submit-btn-duplicate" name="submitCreate" type="submit" value="submitCreate"/>
+      <div class="control-group form-controls">
+        <input class="btn-primary" name="submitCreate" type="submit" value="submitCreate"/>
+      </div>
+      <div class="control-group form-controls">
+        <input class="btn-primary" name="submitDelete" type="submit" value="submitDelete"/>
+      </div>
+    </form>
+HTML;
+
+        $this->form->render();
+
+        $this->assertHtml($expected, $this->form);
+    }
+
+    public function testCreatingDuplicateSubmitButton(): void
+    {
+        $submitButton = new SubmitElement('test_submit', [
+            'class' => 'autosubmit'
+        ]);
+
+        $prefixButton = $this->form->duplicateSubmitButton($submitButton);
+
+        // Name should stay the same
+        $this->assertSame($submitButton->getName(), 'test_submit');
+        $this->assertSame($prefixButton->getName(), 'test_submit');
+
+        // Class attribute should change to `primary-submit-btn-duplicate`
+        $this->assertSame($submitButton->getAttributes()->get('class')->getValue(), 'autosubmit');
+        $this->assertSame($prefixButton->getAttributes()->get('class')->getValue(), 'primary-submit-btn-duplicate');
+    }
+}