Add plugin hooks for assets

app/Helper/Hook.php

@@ -10,6 +10,26 @@ namespace Helper;
  */
 class Hook extends \Core\Base
 {
+    /**
+     * Add assets JS or CSS
+     *
+     * @access public
+     * @param  string  $type
+     * @param  string  $hook
+     * @param  array   $variables
+     * @return string
+     */
+    public function asset($type, $hook)
+    {
+        $buffer = '';
+
+        foreach ($this->hook->getListeners($hook) as $file) {
+            $buffer .= $this->helper->asset->$type($file);
+        }
+
+        return $buffer;
+    }
+
     /**
      * Render all attached hooks
      *

app/Template/layout.php

@@ -21,6 +21,9 @@
         <?= $this->asset->css('assets/css/print.css', true, 'print') ?>
         <?= $this->asset->customCss() ?>
 
+        <?= $this->hook->asset('css', 'template:layout:css') ?>
+        <?= $this->hook->asset('js', 'template:layout:js') ?>
+
         <link rel="icon" type="image/png" href="<?= $this->url->dir() ?>assets/img/favicon.png">
         <link rel="apple-touch-icon" href="<?= $this->url->dir() ?>assets/img/touch-icon-iphone.png">
         <link rel="apple-touch-icon" sizes="72x72" href="<?= $this->url->dir() ?>assets/img/touch-icon-ipad.png">

doc/plugins.markdown

@@ -154,6 +154,34 @@ List of merge hooks:
     - `$start` Calendar start date (string, ISO-8601 format)
     - `$end` Calendar end date (string, ISO-8601 format)
 
+Asset Hooks
+-----------
+
+Asset hooks can be used to add easily a new stylesheet or a new javascript file in the layout. You can use this feature to create a theme and override all Kanboard default styles.
+
+Example to add a new stylesheet:
+
+```php
+<?php
+
+namespace Plugin\Css;
+
+use Core\Plugin\Base;
+
+class Plugin extends Base
+{
+    public function initialize()
+    {
+        $this->hook->on('template:layout:css', 'plugins/Css/skin.css');
+    }
+}
+```
+
+List of asset Hooks:
+
+- `template:layout:css`
+- `template:layout:js`
+
 Template hooks
 --------------
 
@@ -338,3 +366,4 @@ Examples of plugins
 - [User timetable](https://github.com/kanboard/plugin-timetable)
 - [Subtask Forecast](https://github.com/kanboard/plugin-subtask-forecast)
 - [Theme plugin sample](https://github.com/kanboard/plugin-example-theme)
+- [CSS plugin sample](https://github.com/kanboard/plugin-example-css)

tests/units/Helper/HookHelperTest.php

@@ -37,4 +37,38 @@ class HookHelperTest extends Base
         $h->attach('test', 'tpl2');
         $this->assertEquals('tpl1_contenttpl2_content', $h->render('test'));
     }
-}
+
+    public function testAssetHooks()
+    {
+        $this->container['helper']->asset = $this
+            ->getMockBuilder('\Helper\Asset')
+            ->setConstructorArgs(array($this->container))
+            ->setMethods(array('css', 'js'))
+            ->getMock();
+
+        $this->container['helper']
+            ->asset
+            ->expects($this->at(0))
+            ->method('css')
+            ->with(
+                $this->equalTo('skin.css')
+            )
+            ->will($this->returnValue('<link rel="stylesheet" href="skin.css"></link>'));
+
+        $this->container['helper']
+            ->asset
+            ->expects($this->at(1))
+            ->method('js')
+            ->with(
+                $this->equalTo('skin.js')
+            )
+            ->will($this->returnValue('<script src="skin.js"></script>'));
+
+        $h = new Hook($this->container);
+        $h->attach('test1', 'skin.css');
+        $h->attach('test2', 'skin.js');
+
+        $this->assertContains('<link rel="stylesheet" href="skin.css"></link>', $h->asset('css', 'test1'));
+        $this->assertContains('<script src="skin.js"></script>', $h->asset('js', 'test2'));
+    }
+}