From 4a210b068811cc9a043fb47177e945a4a735da6b Mon Sep 17 00:00:00 2001
From: David Monllao <david.monllao@gmail.com>
Date: Wed, 26 Jul 2017 09:17:58 +0200
Subject: [PATCH] MDL-57791 analytics: Predictions deleted context management

---
 .../tool/analytics/classes/output/models_list.php  |  5 -----
 analytics/classes/manager.php                      |  9 ++++++---
 analytics/classes/model.php                        | 14 ++++++++------
 lang/en/analytics.php                              |  2 ++
 report/insights/lang/en/report_insights.php        |  1 -
 5 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/admin/tool/analytics/classes/output/models_list.php b/admin/tool/analytics/classes/output/models_list.php
index d495554ba88..181b48dc48f 100644
--- a/admin/tool/analytics/classes/output/models_list.php
+++ b/admin/tool/analytics/classes/output/models_list.php
@@ -74,11 +74,6 @@ class models_list implements \renderable, \templatable {
                     foreach ($predictioncontexts as $contextid => $unused) {
                         // We prepare this to be used as single_select template options.
                         $context = \context::instance_by_id($contextid);
-                        if (empty($context)) {
-                            // The context may have been deleted.
-                            unset($predictioncontexts[$contextid]);
-                            continue;
-                        }
 
                         // Special name for system level predictions as showing "System is not visually nice".
                         if ($contextid == SYSCONTEXTID) {
diff --git a/analytics/classes/manager.php b/analytics/classes/manager.php
index 152f5a76582..581f917ac78 100644
--- a/analytics/classes/manager.php
+++ b/analytics/classes/manager.php
@@ -370,14 +370,17 @@ class manager {
         global $DB;
 
         if (!$predictionobj = $DB->get_record('analytics_predictions', array('id' => $predictionid))) {
-            throw new \moodle_exception('errorpredictionnotfound', 'report_insights');
+            throw new \moodle_exception('errorpredictionnotfound', 'analytics');
+        }
+
+        $context = \context::instance_by_id($predictionobj->contextid, IGNORE_MISSING);
+        if (!$context) {
+            throw new \moodle_exception('errorpredictioncontextnotavailable', 'analytics');
         }
 
         if ($requirelogin) {
             list($context, $course, $cm) = get_context_info_array($predictionobj->contextid);
             require_login($course, false, $cm);
-        } else {
-            $context = \context::instance_by_id($predictionobj->contextid);
         }
 
         self::check_can_list_insights($context);
diff --git a/analytics/classes/model.php b/analytics/classes/model.php
index fecb10a41e1..a76acd5c096 100644
--- a/analytics/classes/model.php
+++ b/analytics/classes/model.php
@@ -986,7 +986,9 @@ class model {
     public function get_predictions_contexts() {
         global $DB;
 
-        $sql = "SELECT DISTINCT contextid FROM {analytics_predictions} WHERE modelid = ?";
+        $sql = "SELECT DISTINCT ap.contextid FROM {analytics_predictions} ap
+                  JOIN {context} ctx ON ctx.id = ap.contextid
+                 WHERE ap.modelid = ?";
         return $DB->get_records_sql($sql, array($this->model->id));
     }
 
@@ -1044,16 +1046,16 @@ class model {
         \core_analytics\manager::check_can_list_insights($context);
 
         // Filters out previous predictions keeping only the last time range one.
-        $sql = "SELECT tip.*
-                  FROM {analytics_predictions} tip
+        $sql = "SELECT ap.*
+                  FROM {analytics_predictions} ap
                   JOIN (
                     SELECT sampleid, max(rangeindex) AS rangeindex
                       FROM {analytics_predictions}
                      WHERE modelid = ? and contextid = ?
                     GROUP BY sampleid
-                  ) tipsub
-                  ON tip.sampleid = tipsub.sampleid AND tip.rangeindex = tipsub.rangeindex
-                 WHERE tip.modelid = ? and tip.contextid = ?";
+                  ) apsub
+                  ON ap.sampleid = apsub.sampleid AND ap.rangeindex = apsub.rangeindex
+                 WHERE ap.modelid = ? and ap.contextid = ?";
         $params = array($this->model->id, $context->id, $this->model->id, $context->id);
         if (!$predictions = $DB->get_records_sql($sql, $params)) {
             return array();
diff --git a/lang/en/analytics.php b/lang/en/analytics.php
index fc368aaa7d1..6ce2124c940 100644
--- a/lang/en/analytics.php
+++ b/lang/en/analytics.php
@@ -42,7 +42,9 @@ $string['errornopredictresults'] = 'No results returned from the predictions pro
 $string['errornotimesplittings'] = 'This model does not have any time splitting method';
 $string['errornoroles'] = 'Student or teacher roles have not been defined. Define them in analytics settings page.';
 $string['errornotarget'] = 'This model does not have any target';
+$string['errorpredictioncontextnotavailable'] = 'This prediction context is not available anymore';
 $string['errorpredictionformat'] = 'Wrong prediction calculations format';
+$string['errorpredictionnotfound'] = 'Prediction not found';
 $string['errorpredictionsprocessor'] = 'Predictions processor error: {$a}';
 $string['errorpredictwrongformat'] = 'The predictions processor return can not be decoded: "{$a}"';
 $string['errorprocessornotready'] = 'The selected predictions processor is not ready: {$a}';
diff --git a/report/insights/lang/en/report_insights.php b/report/insights/lang/en/report_insights.php
index a5e1d75bb76..17af8e99018 100644
--- a/report/insights/lang/en/report_insights.php
+++ b/report/insights/lang/en/report_insights.php
@@ -24,7 +24,6 @@
 
 
 $string['disabledmodel'] = 'Sorry, this model has been disabled by the administrator';
-$string['errorpredictionnotfound'] = 'Prediction not found';
 $string['insights'] = 'Insights';
 $string['pluginname'] = 'Insights';
 $string['prediction'] = 'Prediction';