From 7366a6f511151815d0654a84bf6dca699b0a5236 Mon Sep 17 00:00:00 2001
From: PMKuipers <pm@miqra.nl>
Date: Tue, 31 Dec 2024 14:02:42 +0100
Subject: [PATCH] Optimized looping queries

---
 classes/associationservice.php | 70 +++++++++++++++++-----------------
 1 file changed, 36 insertions(+), 34 deletions(-)

diff --git a/classes/associationservice.php b/classes/associationservice.php
index 8c11427..e1c3e07 100644
--- a/classes/associationservice.php
+++ b/classes/associationservice.php
@@ -477,20 +477,21 @@ class associationservice extends \external_api {
             webservicehelper::require_capabilities(self::CAP_VIEW, $studyplan->context());
         }
 
-        $sql = "SELECT DISTINCT u.* FROM {user} u INNER JOIN {local_treestudyplan_user} j ON j.user_id = u.id
+        $sql = "SELECT DISTINCT u.*, t.lastaccess as lastaccess 
+                FROM {user} u INNER JOIN {local_treestudyplan_user} j ON j.user_id = u.id
+                LEFT JOIN (SELECT MAX(a.timeaccess) as lastaccess, a.userid as userid FROM {user_lastaccess} a
+                    INNER JOIN {local_treestudyplan_item} i ON i.course_id = a.courseid
+                    INNER JOIN {local_treestudyplan_line} l ON l.id = i.line_id
+                    INNER JOIN {local_treestudyplan_page} p ON l.page_id = p.id
+                    ) t ON t.userid = u.id
                 WHERE j.studyplan_id = :studyplan_id AND u.deleted != 1
                 ORDER BY u.lastname, u.firstname";
         $rs = $DB->get_recordset_sql($sql, ['studyplan_id' => $studyplanid]);
 
-        /*
-            ID: 30
-            page: 33
-            plan: 28
-        */
         $users = [];
-        foreach ($rs as $u) {
-            $user = self::make_user_model($u);
-            $user["lastaccess"] = self::user_lastaccess($u->id, $studyplanid);
+        foreach ($rs as $r) {
+            $user = self::make_user_model($r);
+            $user["lastaccess"] = $r->lastaccess;
             $users[] = $user;
 
         }
@@ -621,7 +622,7 @@ class associationservice extends \external_api {
             webservicehelper::require_capabilities(self::CAP_VIEW, $studyplan->context());
         }
 
-        $userlist = [
+        $userlist = [ 0 =>
             [
                 'id' => 0,
                 'label' => get_string("individuals", 'local_treestudyplan'),
@@ -629,33 +630,34 @@ class associationservice extends \external_api {
             ],
         ];
 
-        $sql = "SELECT DISTINCT c.* FROM {cohort} c INNER JOIN {local_treestudyplan_cohort} j ON j.cohort_id = c.id
-                WHERE j.studyplan_id = :studyplan_id";
-        $crs = $DB->get_recordset_sql($sql, ['studyplan_id' => $studyplanid]);
-        foreach ($crs as $c) {
-            $users = [];
-            $sql = "SELECT DISTINCT u.id, u.username, u.firstname, u.lastname, u.idnumber, u.email
-                    FROM {user} u
-                    LEFT JOIN {cohort_members} cm ON u.id = cm.userid
-                    WHERE cm.cohortid = :cohortid AND u.deleted != 1
-                    ORDER BY u.lastname, u.firstname";
-            $rs = $DB->get_recordset_sql($sql, ["cohortid" => $c->id]);
+        $sql = "SELECT DISTINCT u.id, u.username, u.firstname, u.lastname, u.idnumber, u.email,
+                                c.id as cohortid, c.name as cohortname, t.lastaccess as lastaccess
+                FROM {user} u
+                LEFT JOIN {cohort_members} cm ON u.id = cm.userid
+                LEFT JOIN {cohort} c ON c.id = cm.cohortid
+                LEFT JOIN {local_treestudyplan_cohort} j on j.cohort_id = c.id
+                LEFT JOIN (SELECT MAX(a.timeaccess) as lastaccess, a.userid as userid FROM {user_lastaccess} a
+                    INNER JOIN {local_treestudyplan_item} i ON i.course_id = a.courseid
+                    INNER JOIN {local_treestudyplan_line} l ON l.id = i.line_id
+                    INNER JOIN {local_treestudyplan_page} p ON l.page_id = p.id
+                    ) t ON t.userid = u.id
+                WHERE j.studyplan_id = :studyplan_id AND u.deleted != 1
+                ORDER BY cohortname, u.lastname, u.firstname;";
+        $rs = $DB->get_recordset_sql($sql, ['studyplan_id' => $studyplanid]);
+        foreach ($rs as $r) {
+            $user = self::make_user_model($r);
+            $user["lastaccess"] = empty($r->lastaccess) ? 0 : $r->lastaccess;
 
-            foreach ($rs as $u) {
-                $user = self::make_user_model($u);
-                $user["lastaccess"] = self::user_lastaccess($u->id, $studyplanid);
-                $users[] = $user;
+            if (!array_key_exists($r->cohortid, $userlist)) {
+                $userlist[$r->cohortid] = [
+                    'id' => $r->cohortid,
+                    'label' => $r->cohortname,
+                    'users' => [],
+                ];
             }
-            $rs->close();
-
-            $userlist[] = [
-                'id' => $c->id,
-                'label' => $c->name,
-                'users' => $users,
-            ];
+            $userlist[$r->cohortid]["users"][] = $user;
         }
-        $crs->close();
-
+        $rs->close();
         return $userlist;
     }