From bf7c844e941df51d3bfd4768f24ca4ee8a72e6fe Mon Sep 17 00:00:00 2001
From: Tony Butler <tonyjbutler@gmail.com>
Date: Wed, 18 Mar 2015 16:33:41 +0000
Subject: [PATCH] MDL-49582 core_lib: Add button to allow user to reset table
 preferences

---
 lang/en/moodle.php |  1 +
 lib/tablelib.php   | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/lang/en/moodle.php b/lang/en/moodle.php
index e0f5cd09d0398..78468c78c7e9a 100644
--- a/lang/en/moodle.php
+++ b/lang/en/moodle.php
@@ -1530,6 +1530,7 @@
 $string['resetrecordexpired'] = 'The password reset link you used is more than {$a} minutes old and has expired. Please initiate a new password reset.';
 $string['resetstartdate'] = 'Reset start date';
 $string['resetstatus'] = 'Status';
+$string['resettable'] = 'Reset table preferences';
 $string['resettask'] = 'Task';
 $string['resettodefaults'] = 'Reset to defaults';
 $string['resortsubcategoriesby'] = 'Sort subcategories by {$a} ascending';
diff --git a/lib/tablelib.php b/lib/tablelib.php
index cbf66ac17a366..39afa90c2e43a 100644
--- a/lib/tablelib.php
+++ b/lib/tablelib.php
@@ -34,6 +34,7 @@
 define('TABLE_VAR_IFIRST', 4);
 define('TABLE_VAR_ILAST',  5);
 define('TABLE_VAR_PAGE',   6);
+define('TABLE_VAR_RESET',  7);
 /**#@-*/
 
 /**#@+
@@ -138,6 +139,7 @@ function __construct($uniqueid) {
             TABLE_VAR_IFIRST => 'tifirst',
             TABLE_VAR_ILAST  => 'tilast',
             TABLE_VAR_PAGE   => 'page',
+            TABLE_VAR_RESET  => 'treset'
         );
     }
 
@@ -508,6 +510,17 @@ function setup() {
             $this->prefs['i_first'] = $ifirst;
         }
 
+        // Allow user to reset table preferences.
+        if (optional_param($this->request[TABLE_VAR_RESET], 0, PARAM_BOOL) === 1) {
+            $this->prefs = array(
+                'collapse' => array(),
+                'sortby'   => array(),
+                'i_first'  => '',
+                'i_last'   => '',
+                'textsort' => $this->column_textsort,
+            );
+        }
+
         // Save user preferences if they have changed.
         if ($this->prefs != $oldprefs) {
             if ($this->persistent) {
@@ -971,6 +984,10 @@ function print_initials_bar() {
      */
     function print_nothing_to_display() {
         global $OUTPUT;
+
+        // Render button to allow user to reset table preferences.
+        echo $this->render_reset_button();
+
         $this->print_initials_bar();
 
         echo $OUTPUT->heading(get_string('nothingtodisplay'));
@@ -1325,6 +1342,10 @@ protected function sort_link($text, $column, $isprimary, $order) {
      */
     function start_html() {
         global $OUTPUT;
+
+        // Render button to allow user to reset table preferences.
+        echo $this->render_reset_button();
+
         // Do we need to print initial bars?
         $this->print_initials_bar();
 
@@ -1363,6 +1384,21 @@ function make_styles_string($styles) {
         }
         return $string;
     }
+
+    /**
+     * Generate the HTML for the table preferences reset button.
+     *
+     * @return string HTML fragment.
+     */
+    private function render_reset_button() {
+        $url = $this->baseurl->out(false, array($this->request[TABLE_VAR_RESET] => 1));
+
+        $html  = html_writer::start_div('mdl-right');
+        $html .= html_writer::link($url, get_string('resettable'));
+        $html .= html_writer::end_div();
+
+        return $html;
+    }
 }