Form: Add hint support

Hints are short messages displayed at the bottom of a form
used to describe specific aspects on how to interact with
the form.

refs #8983

library/Icinga/Web/Form.php

@@ -160,6 +160,13 @@ class Form extends Zend_Form
      */
     protected $notifications;
 
+    /**
+     * The hints of this form
+     *
+     * @var array
+     */
+    protected $hints;
+
     /**
      * Whether the Autosubmit decorator should be applied to this form
      *
@@ -566,6 +573,49 @@ class Form extends Zend_Form
         return $this->notifications;
     }
 
+    /**
+     * Set the hints for this form
+     *
+     * @param   array   $hints
+     *
+     * @return  $this
+     */
+    public function setHints(array $hints)
+    {
+        $this->hints = $hints;
+        return $this;
+    }
+
+    /**
+     * Add a hint for this form
+     *
+     * If $hint is an array the second value should be an
+     * array as well containing additional HTML properties.
+     *
+     * @param   string|array    $hint
+     *
+     * @return  $this
+     */
+    public function addHint($hint)
+    {
+        $this->hints[] = $hint;
+        return $this;
+    }
+
+    /**
+     * Return the hints of this form
+     *
+     * @return  array
+     */
+    public function getHints()
+    {
+        if ($this->hints === null) {
+            return array();
+        }
+
+        return $this->hints;
+    }
+
     /**
      * Set whether the Autosubmit decorator should be applied to this form
      *
@@ -1091,6 +1141,7 @@ class Form extends Zend_Form
                     ->addDecorator('FormNotifications')
                     ->addDecorator('FormErrors', array('onlyCustomFormErrors' => true))
                     ->addDecorator('FormElements')
+                    ->addDecorator('FormHints')
                     //->addDecorator('HtmlTag', array('tag' => 'dl', 'class' => 'zend_form'))
                     ->addDecorator('Form');
             }

library/Icinga/Web/Form/Decorator/FormHints.php

@@ -0,0 +1,142 @@
+<?php
+/* Icinga Web 2 | (c) 2013-2015 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Web\Form\Decorator;
+
+use Zend_Form_Decorator_Abstract;
+use Icinga\Web\Form;
+
+/**
+ * Decorator to add a list of hints at the top or bottom of a form
+ *
+ * The hint for required form elements is automatically being handled.
+ */
+class FormHints extends Zend_Form_Decorator_Abstract
+{
+    /**
+     * A list of element class names to be ignored when detecting which message to use to describe required elements
+     *
+     * @var array
+     */
+    protected $blacklist;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __construct($options = null)
+    {
+        parent::__construct($options);
+        $this->blacklist = array(
+            'Zend_Form_Element_Hidden',
+            'Zend_Form_Element_Submit',
+            'Zend_Form_Element_Button',
+            'Icinga\Web\Form\Element\Note',
+            'Icinga\Web\Form\Element\Button',
+            'Icinga\Web\Form\Element\CsrfCounterMeasure'
+        );
+    }
+
+    /**
+     * Render form hints
+     *
+     * @param   string      $content    The html rendered so far
+     *
+     * @return  string                  The updated html
+     */
+    public function render($content = '')
+    {
+        $form = $this->getElement();
+        if (! $form instanceof Form) {
+            return $content;
+        }
+
+        $view = $form->getView();
+        if ($view === null) {
+            return $content;
+        }
+
+        $hints = $this->recurseForm($form, $entirelyRequired);
+        if ($entirelyRequired !== null) {
+            $hints[] = $form->getView()->translate(sprintf(
+                'Required fields are marked with %s and must be filled in to complete the form.',
+                $form->getRequiredCue()
+            ));
+        }
+
+        if (empty($hints)) {
+            return $content;
+        }
+
+        $html = '<ul class="hints">';
+        foreach ($hints as $hint) {
+            if (is_array($hint)) {
+                list($hint, $properties) = $hint;
+                $html .= '<li' . $view->propertiesToString($properties) . '>' . $view->escape($hint) . '</li>';
+            } else {
+                $html .= '<li>' . $view->escape($hint) . '</li>';
+            }
+        }
+
+        switch ($this->getPlacement()) {
+            case self::APPEND:
+                return $content . $html . '</ul>';
+            case self::PREPEND:
+                return $html . '</ul>' . $content;
+        }
+    }
+
+    /**
+     * Recurse the given form and return the hints for it and all of its subforms
+     *
+     * @param   Form    $form               The form to recurse
+     * @param   mixed   $entirelyRequired   Set by reference, true means all elements in the hierarchy are
+     *                                       required, false only a partial subset and null none at all
+     * @param   bool    $elementsPassed     Whether there were any elements passed during the recursion until now
+     *
+     * @return  array
+     */
+    protected function recurseForm(Form $form, & $entirelyRequired = null, $elementsPassed = false)
+    {
+        $requiredLabels = array();
+        if ($form->getRequiredCue() !== null) {
+            $partiallyRequired = $partiallyOptional = false;
+            foreach ($form->getElements() as $element) {
+                if (! in_array($element->getType(), $this->blacklist)) {
+                    if (! $element->isRequired()) {
+                        $partiallyOptional = true;
+                        if ($entirelyRequired) {
+                            $entirelyRequired = false;
+                        }
+                    } else {
+                        $partiallyRequired = true;
+                        if (($label = $element->getDecorator('label')) !== false) {
+                            $requiredLabels[] = $label;
+                        }
+                    }
+                }
+            }
+
+            if (! $elementsPassed) {
+                $elementsPassed = $partiallyRequired || $partiallyOptional;
+                if ($entirelyRequired === null && $partiallyRequired) {
+                    $entirelyRequired = ! $partiallyOptional;
+                }
+            } elseif ($entirelyRequired === null && $partiallyRequired) {
+                $entirelyRequired = false;
+            }
+        }
+
+        $hints = array($form->getHints());
+        foreach ($form->getSubForms() as $subForm) {
+            $hints[] = $this->recurseForm($subForm, $entirelyRequired, $elementsPassed);
+        }
+
+        if ($entirelyRequired) {
+            foreach ($requiredLabels as $label) {
+                $label->setRequiredSuffix('');
+            }
+        }
+
+        return call_user_func_array('array_merge', $hints);
+    }
+}

public/css/icinga/forms.less

@@ -259,3 +259,13 @@ form ul.descriptions {
     }
   }
 }
+
+form ul.hints {
+  .non-list-like-list;
+  padding: 0.5em 0.5em 0 0.5em;
+
+  li {
+    font-size: 0.8em;
+    padding-bottom: 0.5em;
+  }
+}