FEATURE: add functionality for modifying content page on template level

app/Handlers/Contracts/TemplateHandler.php

@@ -1,14 +1,64 @@
 <?php
 namespace App\Handlers\Contracts;
 
+use App\Http\Requests\Request;
 use App\Models\Content;
 use App\Models\Module;
 
+/**
+ * Interface TemplateHandler
+ *
+ * Inerface used for registering template into CMS core.
+ *
+ * @package App\Handlers\Contracts
+ */
 interface TemplateHandler extends BaseModuleHandler
 {
+    /**
+     * Uninstall template
+     *
+     * Delete some items in database, delete files etc.
+     *
+     * @param Module $template
+     */
     public static function uninstall(Module $template);
 
+    /**
+     * Get list of registered templates and supported modules.
+     *
+     * Returned array is expected to be array of arrays with following items: module, namespace and templateName.
+     * Example:
+     * return [
+     *    ['module' => 'Article', 'templateName' => 'article::template.name']
+     * ];
+     *
+     * When no "namespace" is specified, value strtolower(module) is used instaed.
+     *
+     * @return array
+     */
     public static function getPublicTemplatePaths();
 
-    public static function beforeRender(Content $content);
+    /**
+     * Prepare Content object to be rendered using Blade template
+     *
+     * @param Content $content
+     */
+    public static function beforeRender(Content & $content);
+
+    /**
+     * Modify input data into format which can be understood by edit template
+     *
+     * @param Content $content
+     */
+    public static function beforePopulatingEditForm(Content & $content);
+
+    /**
+     * Slightly modify Content object before saving into database.
+     *
+     * This way we can do almost whatever we want - even in template
+     *
+     * @param Content $content
+     * @param Request $request
+     */
+    public static function beforeSave(Content & $content, Request $request);
 }