Add notification when report w/ segment has no data, but segment is unprocessed (#12823)3.6.0-b4

* When a report has no data, check if it is for an unprocessed segment and display an explanatory notification.

* Remove transient notifications on reporting page change, allow datatable views to add notifications, use to display unprocessed segment message.

* Update changelog.

* Internationalize unprocessed segment message.

* Parse notification divs in dashboardWidget.js when setting widget content.

* Tweak message.

* Change PR to use different approach: throw exception when no archives found and segment is used, then detect exception in new event.

* Update changelog + document new event.

* Unfinished review changes

* more review fixes

* Do not show notification w/ custom segments.

* apply pr review

* Apply review.

* undo escaping since it was not needed & get test to pass

* Different strategy + new test.

* Fix tests.

* Update two expected screenshots.

1 files changed, 20 insertions, 1 deletions

diff --git a/core/Plugin/Visualization.php b/core/Plugin/Visualization.php
index 5f5a58462f..6d948ae536 100644
--- a/core/Plugin/Visualization.php
+++ b/core/Plugin/Visualization.php
@@ -209,12 +209,12 @@ class Visualization extends ViewDataTable
         }
 
         $view = new View("@CoreHome/_dataTable");
+        $view->assign($this->templateVars);
 
         if (!empty($loadingError)) {
             $view->error = $loadingError;
         }
 
-        $view->assign($this->templateVars);
         $view->visualization         = $this;
         $view->visualizationTemplate = static::TEMPLATE_FILE;
         $view->visualizationCssClass = $this->getDefaultDataTableCssClass();
@@ -243,10 +243,29 @@ class Visualization extends ViewDataTable
         $view->reportLastUpdatedMessage = $this->reportLastUpdatedMessage;
         $view->footerIcons = $this->config->footer_icons;
         $view->isWidget    = Common::getRequestVar('widget', 0, 'int');
+        $view->notifications = [];
+
+        if (empty($this->dataTable) || !$this->hasAnyData($this->dataTable)) {
+            /**
+             * @ignore
+             */
+            Piwik::postEvent('Visualization.onNoData', [$view]);
+        }
 
         return $view->render();
     }
 
+    private function hasAnyData(DataTable\DataTableInterface $dataTable)
+    {
+        $hasData = false;
+        $dataTable->filter(function (DataTable $table) use (&$hasData) {
+            if ($table->getRowsCount() > 0) {
+                $hasData = true;
+            }
+        });
+        return $hasData;
+    }
+
     /**
      * @internal
      */