From 3c92b1d4e55196cb5de306bb30dee07d0a54f293 Mon Sep 17 00:00:00 2001
From: Paul Holden <pholden@greenhead.ac.uk>
Date: Thu, 4 Apr 2019 16:08:26 +0100
Subject: [PATCH] MDL-64784 core: consistent column sort direction in
 flexible_table.

---
 lib/tablelib.php | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/lib/tablelib.php b/lib/tablelib.php
index d1213b89b47..421632cbc0c 100644
--- a/lib/tablelib.php
+++ b/lib/tablelib.php
@@ -35,6 +35,7 @@ define('TABLE_VAR_IFIRST', 4);
 define('TABLE_VAR_ILAST',  5);
 define('TABLE_VAR_PAGE',   6);
 define('TABLE_VAR_RESET',  7);
+define('TABLE_VAR_DIR',    8);
 /**#@-*/
 
 /**#@+
@@ -150,7 +151,8 @@ class flexible_table {
             TABLE_VAR_IFIRST => 'tifirst',
             TABLE_VAR_ILAST  => 'tilast',
             TABLE_VAR_PAGE   => 'page',
-            TABLE_VAR_RESET  => 'treset'
+            TABLE_VAR_RESET  => 'treset',
+            TABLE_VAR_DIR    => 'tdir',
         );
     }
 
@@ -516,14 +518,16 @@ class flexible_table {
                 (isset($this->columns[$sortcol]) || in_array($sortcol, get_all_user_name_fields())
                 && isset($this->columns['fullname']))) {
 
+            $sortdir = optional_param($this->request[TABLE_VAR_DIR], $this->sort_default_order, PARAM_INT);
+
             if (array_key_exists($sortcol, $this->prefs['sortby'])) {
                 // This key already exists somewhere. Change its sortorder and bring it to the top.
-                $sortorder = $this->prefs['sortby'][$sortcol] == SORT_ASC ? SORT_DESC : SORT_ASC;
+                $sortorder = $this->prefs['sortby'][$sortcol] = $sortdir;
                 unset($this->prefs['sortby'][$sortcol]);
                 $this->prefs['sortby'] = array_merge(array($sortcol => $sortorder), $this->prefs['sortby']);
             } else {
                 // Key doesn't exist, so just add it to the beginning of the array, ascending order
-                $this->prefs['sortby'] = array_merge(array($sortcol => SORT_ASC), $this->prefs['sortby']);
+                $this->prefs['sortby'] = array_merge(array($sortcol => $sortdir), $this->prefs['sortby']);
             }
 
             // Finally, make sure that no more than $this->maxsortkeys are present into the array
@@ -1362,8 +1366,19 @@ class flexible_table {
      * @return string HTML fragment.
      */
     protected function sort_link($text, $column, $isprimary, $order) {
-        return html_writer::link($this->baseurl->out(false,
-                array($this->request[TABLE_VAR_SORT] => $column)),
+        // If we are already sorting by this column, switch direction.
+        if (array_key_exists($column, $this->prefs['sortby'])) {
+            $sortorder = $this->prefs['sortby'][$column] == SORT_ASC ? SORT_DESC : SORT_ASC;
+        } else {
+            $sortorder = $order;
+        }
+
+        $params = [
+            $this->request[TABLE_VAR_SORT] => $column,
+            $this->request[TABLE_VAR_DIR] => $sortorder,
+        ];
+
+        return html_writer::link($this->baseurl->out(false, $params),
                 $text . get_accesshide(get_string('sortby') . ' ' .
                 $text . ' ' . $this->sort_order_name($isprimary, $order))) . ' ' .
                 $this->sort_icon($isprimary, $order);