MDL-59060 analytics: Add paging to insights report

Part of MDL-57791 epic.

analytics/classes/model.php

@@ -1001,9 +1001,11 @@ public function predictions_exist(\context $context) {
      * Gets the predictions for this context.
      *
      * @param \context $context
-     * @return \core_analytics\prediction[]
+     * @param int $page The page of results to fetch
+     * @param int $perpage The max number of results to fetch
+     * @return array($total, \core_analytics\prediction[])
      */
-    public function get_predictions(\context $context) {
+    public function get_predictions(\context $context, $page = 0, $perpage = 100) {
         global $DB;
 
         \core_analytics\manager::check_can_list_insights($context);
@@ -1032,6 +1034,12 @@ public function get_predictions(\context $context) {
         list($unused, $samplesdata) = $this->get_analyser()->get_samples($sampleids);
 
         // Add samples data as part of each prediction.
+        $paginated = [];
+
+        $current = 0;
+        $offset = $page * $perpage;
+        $limit = $offset + $perpage;
+
         foreach ($predictions as $predictionid => $predictiondata) {
 
             $sampleid = $predictiondata->sampleid;
@@ -1042,13 +1050,19 @@ public function get_predictions(\context $context) {
                 continue;
             }
 
-            // Replace \stdClass object by \core_analytics\prediction objects.
-            $prediction = new \core_analytics\prediction($predictiondata, $samplesdata[$sampleid]);
+            // Return paginated dataset - we cannot paginate in the DB because we post filter the list.
+            if ($current >= $offset && $current < $limit) {
+                // Replace \stdClass object by \core_analytics\prediction objects.
+                $prediction = new \core_analytics\prediction($predictiondata, $samplesdata[$sampleid]);
+                $predictions[$predictionid] = $prediction;
+            } else {
+                unset($predictions[$predictionid]);
+            }
 
-            $predictions[$predictionid] = $prediction;
+            $current++;
         }
 
-        return $predictions;
+        return [$current, $predictions];
     }
 
     /**

report/insights/classes/output/insights_list.php

@@ -50,18 +50,32 @@ class insights_list implements \renderable, \templatable {
      */
     protected $othermodels;
 
+    /**
+     * @var int
+     */
+    protected $page;
+
+    /**
+     * @var int
+     */
+    protected $perpage;
+
     /**
      * Constructor
      *
      * @param \core_analytics\model $model
      * @param \context $context
      * @param \core_analytics\model[] $othermodels
+     * @param int $page
+     * @param int $perpage The max number of results to fetch
      * @return void
      */
-    public function __construct(\core_analytics\model $model, \context $context, $othermodels) {
+    public function __construct(\core_analytics\model $model, \context $context, $othermodels, $page = 0, $perpage = 100) {
         $this->model = $model;
         $this->context = $context;
         $this->othermodels = $othermodels;
+        $this->page = $page;
+        $this->perpage = $perpage;
     }
 
     /**
@@ -74,17 +88,18 @@ public function export_for_template(\renderer_base $output) {
         global $PAGE;
 
         $data = new \stdClass();
+        $total = 0;
 
         if ($this->model->uses_insights()) {
-            $predictions = $this->model->get_predictions($this->context);
+            list($total, $predictions) = $this->model->get_predictions($this->context, $this->page, $this->perpage);
 
             $data->insights = array();
             foreach ($predictions as $prediction) {
                 $insightrenderable = new \report_insights\output\insight($prediction, $this->model, true);
                 $data->insights[] = $insightrenderable->export_for_template($output);
             }
 
-            if (empty($data->insights)) {
+            if (empty($data->insights) && $this->page == 0) {
                 if ($this->model->any_prediction_obtained()) {
                     $data->noinsights = get_string('noinsights', 'analytics');
                 } else {
@@ -115,6 +130,8 @@ public function export_for_template(\renderer_base $output) {
             $data->modelselector = $modelselector->export_for_template($output);
         }
 
+        $data->pagingbar = $output->render(new \paging_bar($total, $this->page, $this->perpage, $PAGE->url));
+
         return $data;
     }
 }

report/insights/insights.php

@@ -26,6 +26,12 @@
 
 $contextid = required_param('contextid', PARAM_INT);
 $modelid = optional_param('modelid', false, PARAM_INT);
+$page = optional_param('page', 0, PARAM_INT);
+$perpage = optional_param('perpage', 100, PARAM_INT);
+
+if ($perpage > 1000) {
+    $perpage = 1000;
+}
 
 list($context, $course, $cm) = get_context_info_array($contextid);
 require_login($course, false, $cm);
@@ -85,7 +91,7 @@
 
 echo $OUTPUT->header();
 
-$renderable = new \report_insights\output\insights_list($model, $context, $othermodels);
+$renderable = new \report_insights\output\insights_list($model, $context, $othermodels, $page, $perpage);
 echo $renderer->render($renderable);
 
 echo $OUTPUT->footer();

report/insights/templates/insights_list.mustache

@@ -42,7 +42,8 @@
                 "predictionstyle": "alert alert-danger",
                 "predictiondisplayvalue": "This dev will not understand it"
             }
-        ]
+        ],
+        "noinsights": false
     }
 }}
 
@@ -53,11 +54,15 @@
 {{/modelselector}}
 
 <h3>{{#str}} insights, report_insights {{/str}}</h3>
+{{^noinsights}}
+{{{ pagingbar }}}
 <div class="insights-list">
     {{#insights}}
         {{> report_insights/insight}}
     {{/insights}}
 </div>
+{{{ pagingbar }}}
+{{/noinsights}}
 {{#noinsights}}
     <div class="m-t-2">
         {{> core/notification_info}}