CRM-18792 - CRM_Core_Theme - Add helper for loading CSS files from th…

…emes

CRM-18792 - CRM_Core_Resources - Load civicrm.css through theme system

CRM-18792 - Rename `CRM_Core_Theme` to `\Civi\Core\Theme`

CRM-18792 - Civi\Core\Theme - Remove statics

WIP

CRM_Core_Resources::addCoreStyles - Revert change

CRM-18792 - addStyleFile - Always pass through to theme. Support fallback.

Rename `Civi\Core\Theme` to `Civi\Core\Themes`

The class manages a list of themes -- not just a single theme.

CRM-18792 - Add org.civicrm.demotheme

CRM-18792 - Add uncommitted test files (`Civi\Core\Themes`)

CRM-18792 - Fix regression in CRM_Core_ResourceTest

CRM-18792 - Theme naming - Use prefix '_' for hidden themes

This cleans up a few things:

 * Previously, there was a special case for using FALLBACK in `search_order`.
 * If you're creating a multitheme extension, you may want to define a base theme
   (which is extended by the others). Previously, you were required to show this
   base theme as a user-selectable option. Now, it can be hidden.
 * There was a bug where `resolveUrl()` would sometimes call the wrong callback.
   (It used resolver for `$active` instead of `$themeKey`.)

CRM-18792 - Themes - File overrides and excludes should use same naming

Previously, when using `addStyleFile($cssExt,$css$file)`, the file overrides
and exlcudes would combine them differently e.g.

 * For `addStyleFile('civicrm','css/bootstrap.css')`
   * Override `css/bootstrap.css`
   * Exclude `civicrm:css/bootstrap.css`
 * For `('org.foo.bar','css/bang.css')`
   * Override `org.foo.bar-css/bang.css`
   * Exclude `org.foo.bar:css/bang.css`

Now, they use the same notation:

 * For `addStyleFile('civicrm','css/bootstrap.css')`
   * Override `css/bootstrap.css`
   * Exclude `css/bootstrap.css`
 * For `('org.foo.bar','css/bang.css')`
   * Override `org.foo.bar-css/bang.css`
   * Exclude `org.foo.bar-css/bang.css`

"Display Preferences" - Add the `theme_backend` and `theme_frontend` settings

hook_civicrm_activeTheme - Allow extensions and CMS modules to choose active theme

CRM_Utils_Hook::themes() - Tweak docblock

Civi\Core\Themes - Move cache from `short` to `long`

Remove tools/extensions/org.civicrm.demotheme

Fix merge ahem errors

CRM/Admin/Form/Preferences/Display.php

@@ -53,6 +53,8 @@ class CRM_Admin_Form_Preferences_Display extends CRM_Admin_Form_Preferences {
     'sort_name_format' => CRM_Core_BAO_Setting::SYSTEM_PREFERENCES_NAME,
     'menubar_position' => CRM_Core_BAO_Setting::SYSTEM_PREFERENCES_NAME,
     'menubar_color' => CRM_Core_BAO_Setting::SYSTEM_PREFERENCES_NAME,
+    'theme_backend' => CRM_Core_BAO_Setting::SYSTEM_PREFERENCES_NAME,
+    'theme_frontend' => CRM_Core_BAO_Setting::SYSTEM_PREFERENCES_NAME,
   ];
 
   /**

CRM/Core/Resources.php

@@ -211,8 +211,8 @@ public function addScriptFile($ext, $file, $weight = self::DEFAULT_WEIGHT, $regi
       $domain = ($translate === TRUE) ? $ext : $translate;
       $this->addString($this->strings->get($domain, $this->getPath($ext, $file), 'text/javascript'), $domain);
     }
-    $this->resolveFileName($file, $ext);
-    return $this->addScriptUrl($this->getUrl($ext, $file, TRUE), $weight, $region);
+    $url = $this->getUrl($ext, $this->filterMinify($ext, $file), TRUE);
+    return $this->addScriptUrl($url, $weight, $region);
   }
 
   /**
@@ -427,8 +427,12 @@ public function addString($text, $domain = 'civicrm') {
    * @return CRM_Core_Resources
    */
   public function addStyleFile($ext, $file, $weight = self::DEFAULT_WEIGHT, $region = self::DEFAULT_REGION) {
-    $this->resolveFileName($file, $ext);
-    return $this->addStyleUrl($this->getUrl($ext, $file, TRUE), $weight, $region);
+    /** @var Civi\Core\Themes $theme */
+    $theme = Civi::service('themes');
+    foreach ($theme->resolveUrls($theme->getActiveThemeKey(), $ext, $file) as $url) {
+      $this->addStyleUrl($url, $weight, $region);
+    }
+    return $this;
   }
 
   /**
@@ -937,18 +941,22 @@ public static function getEntityRefMetadata() {
   }
 
   /**
-   * In debug mode, look for a non-minified version of this file
+   * Determine the minified file name.
    *
-   * @param string $fileName
-   * @param string $extName
-   */
-  private function resolveFileName(&$fileName, $extName) {
-    if (CRM_Core_Config::singleton()->debug && strpos($fileName, '.min.') !== FALSE) {
-      $nonMiniFile = str_replace('.min.', '.', $fileName);
-      if ($this->getPath($extName, $nonMiniFile)) {
-        $fileName = $nonMiniFile;
+   * @param string $ext
+   * @param string $file
+   * @return string
+   *   An updated $fileName. If a minified version exists and is supported by
+   *   system policy, the minified version will be returned. Otherwise, the original.
+   */
+  public function filterMinify($ext, $file) {
+    if (CRM_Core_Config::singleton()->debug && strpos($file, '.min.') !== FALSE) {
+      $nonMiniFile = str_replace('.min.', '.', $file);
+      if ($this->getPath($ext, $nonMiniFile)) {
+        $file = $nonMiniFile;
       }
     }
+    return $file;
   }
 
   /**

CRM/Utils/Hook.php

@@ -602,6 +602,63 @@ public static function alterMenu(&$items) {
     );
   }
 
+  /**
+   * A theme is a set of CSS files which are loaded on CiviCRM pages. To register a new
+   * theme, add it to the $themes array. Use these properties:
+   *
+   *  - ext: string (required)
+   *         The full name of the extension which defines the theme.
+   *         Ex: "org.civicrm.themes.greenwich".
+   *  - title: string (required)
+   *         Visible title.
+   *  - help: string (optional)
+   *         Description of the theme's appearance.
+   *  - url_callback: mixed (optional)
+   *         A function ($themes, $themeKey, $cssExt, $cssFile) which returns the URL(s) for a CSS resource.
+   *         Returns either an array of URLs or PASSTHRU.
+   *         Ex: \Civi\Core\Themes\Resolvers::simple (default)
+   *         Ex: \Civi\Core\Themes\Resolvers::none
+   *  - prefix: string (optional)
+   *         A prefix within the extension folder to prepend to the file name.
+   *  - search_order: array (optional)
+   *         A list of themes to search.
+   *         Generally, the last theme should be "*fallback*" (Civi\Core\Themes::FALLBACK).
+   *  - excludes: array (optional)
+   *         A list of files (eg "civicrm:css/bootstrap.css" or "$ext:$file") which should never
+   *         be returned (they are excluded from display).
+   *
+   * @param array $themes
+   *   List of themes, keyed by name.
+   * @return null
+   *   the return value is ignored
+   */
+  public static function themes(&$themes) {
+    return self::singleton()->invoke(1, $themes,
+      self::$_nullObject, self::$_nullObject, self::$_nullObject, self::$_nullObject, self::$_nullObject,
+      'civicrm_themes'
+    );
+  }
+
+  /**
+   * The activeTheme hook determines which theme is active.
+   *
+   * @param string $theme
+   *   The identifier for the theme. Alterable.
+   *   Ex: 'greenwich'.
+   * @param array $context
+   *   Information about the current page-request. Includes some mix of:
+   *   - page: the relative path of the current Civi page (Ex: 'civicrm/dashboard').
+   *   - themes: an instance of the Civi\Core\Themes service.
+   * @return null
+   *   the return value is ignored
+   */
+  public static function activeTheme(&$theme, $context) {
+    return self::singleton()->invoke(array('theme', 'context'), $theme, $context,
+      self::$_nullObject, self::$_nullObject, self::$_nullObject, self::$_nullObject,
+      'civicrm_activeTheme'
+    );
+  }
+
   /**
    * This hook is called for declaring managed entities via API.
    *

Civi/Core/Container.php

@@ -179,6 +179,11 @@ public function createContainer() {
       []
     ));
 
+    $container->setDefinition('themes', new Definition(
+      'Civi\Core\Themes',
+      []
+    ));
+
     $container->setDefinition('pear_mail', new Definition('Mail'))
       ->setFactory('CRM_Utils_Mail::createMailer');