Add SubMenu view helper

The submenu() view helper renders submenus by leaving out the
parent container. This allows to create sidebar-like navigations
for websites with complex navigation structures.

config/module.config.php

@@ -43,12 +43,13 @@
     'controller_plugins' => array(
         'invokables' => array(
             'accept'     => 'Soflomo\Common\Controller\Plugin\Accept',
-            'attachment' => 'Soflomo\Common\Controller\Plugin\Attachment'
+            'attachment' => 'Soflomo\Common\Controller\Plugin\Attachment',
         ),
     ),
     'view_helpers' => array(
         'invokables' => array(
-            'version'    => 'Soflomo\Common\View\Helper\Version'
+            'submenu'    => 'Soflomo\Common\View\Helper\SubMenu',
+            'version'    => 'Soflomo\Common\View\Helper\Version',
         ),
     ),
 );

src/Common/View/Helper/SubMenu.php

@@ -0,0 +1,123 @@
+<?php
+/**
+ * Copyright (c) 2013 Jurian Sluiman.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ *   * Neither the names of the copyright holders nor the names of the
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @author      Jurian Sluiman <jurian@soflomo.com>
+ * @copyright   2013 Jurian Sluiman.
+ * @license     http://www.opensource.org/licenses/bsd-license.php  BSD License
+ * @link        http://soflomo.com
+ */
+
+namespace Soflomo\Common\View\Helper;
+
+use Zend\View\Helper\AbstractHelper;
+
+class SubMenu extends AbstractHelper
+{
+    protected $level = 0;
+    protected $class;
+    protected $header;
+
+    public function __invoke()
+    {
+        return $this;
+    }
+
+    public function setLevel($level)
+    {
+        $this->level = (int) $level;
+        return $this;
+    }
+
+    public function setClass($class)
+    {
+        $this->class = (string) $class;
+        return $this;
+    }
+
+    public function setHeader($header)
+    {
+        $this->header = (string) $header;
+        return $this;
+    }
+
+    public function __toString()
+    {
+        $view = $this->getView();
+        $menu = $view->navigation()->menu();
+
+        $current = $menu->getContainer();
+        $flag    = $menu->getRenderInvisible();
+        $active  = $menu->setRenderInvisible(true)->findActive($current);
+        $menu->setRenderInvisible($flag);
+
+        if (!$active) {
+            return;
+        }
+
+        $container = $active['page'];
+        $depth     = $active['depth'];
+
+        while ($this->level !== $depth) {
+            $container = $container->getParent();
+            $depth--;
+        }
+
+        // Set container explicitly to visible
+        $flag = $container->isVisible();
+        $container->setVisible(true);
+
+        $html = $menu->setContainer($container)
+                     ->setUlClass('')
+                     ->setOnlyActiveBranch(false)
+                     ->setMinDepth(null)
+                     ->setMaxDepth(null)
+                     ->render();
+
+        // Reset the visibility flag
+        $container->setVisible($flag);
+        // Reset the container
+        $menu->setContainer($current);
+
+        if (strlen($html)) {
+            $label = $this->header ?: $container->getLabel();
+
+            return sprintf('<ul%s><li%s><a href="%s">%s</a>%s</li></ul>',
+                    (null !== $this->class) ? ' class="' . $this->class . '"' : null,
+                    ($container->isActive())? ' class="active"' : null,
+                    $container->getHref(),
+                    $label,
+                    $html);
+        }
+    }
+}