From 41c96651b5436a657f27b191e0df7d2f995d2068 Mon Sep 17 00:00:00 2001
From: tjhunt <tjhunt>
Date: Thu, 23 Oct 2008 09:23:52 +0000
Subject: [PATCH] question bank category editing: To be honest, I can't
 rememeber exactly what bug this fixes, but it was a problem I found and fixed
 while preparing to demo stuff at the Brisbane Moodle Moot. In the process of
 fixing whatever issue it was (I think it was something to do with the
 permissions checks in some cases) I cleaned to code up and made it easier to
 understand, and I trust myself, so I am checking this in.

---
 question/category_class.php | 79 ++++++++++++++++++++-----------------
 1 file changed, 42 insertions(+), 37 deletions(-)

diff --git a/question/category_class.php b/question/category_class.php
index 486178d076..c6ef91ddbf 100644
--- a/question/category_class.php
+++ b/question/category_class.php
@@ -360,14 +360,14 @@ class question_category_object {
     public function move_questions($oldcat, $newcat){
         global $DB;
         $questionids = $DB->get_records_select_menu('question', "category = ? AND (parent = 0 OR parent = id)", array($oldcat), '', 'id,1');
-        if (!question_move_questions_to_category(implode(',', array_keys($questionids)), $newcat)) {
-            print_error('errormovingquestions', 'question', $returnurl, $ids);
+        $ids = implode(',', array_keys($questionids));
+        if (!question_move_questions_to_category($ids, $newcat)) {
+            print_error('errormovingquestions', 'question', $this->pageurl->out(), $ids);
         }
     }
 
     /**
      * Creates a new category with given params
-     *
      */
     public function add_category($newparent, $newcategory, $newinfo) {
         global $DB;
@@ -400,7 +400,6 @@ class question_category_object {
 
     /**
      * Updates an existing category with given params
-     *
      */
     public function update_category($updateid, $newparent, $newname, $newinfo) {
         global $CFG, $QTYPES, $DB;
@@ -408,51 +407,57 @@ class question_category_object {
             print_error('categorynamecantbeblank', 'quiz');
         }
 
-        list($parentid, $tocontextid) = explode(',', $newparent);
-
+        // Get the record we are updating.
         $oldcat = $DB->get_record('question_categories', array('id' => $updateid));
+        $lastcategoryinthiscontext = !$DB->record_exists_select('question_categories',
+                    'contextid = ? AND id <> ?', array($oldcat->contextid, $updateid));
+
+        if (!empty($newparent) && !$lastcategoryinthiscontext) {
+            list($parentid, $tocontextid) = explode(',', $newparent);
+        } else {
+            $parentid = $oldcat->parent;
+            $tocontextid = $oldcat->contextid;
+        }
+
+        // Check permissions.
         $fromcontext = get_context_instance_by_id($oldcat->contextid);
         require_capability('moodle/question:managecategory', $fromcontext);
-        if ($oldcat->contextid == $tocontextid){
+
+        // If moving to another context, check permissions some more.
+        if ($oldcat->contextid != $tocontextid){
+            if ($lastcategoryinthiscontext) {
+                // Don't allow the last category in a context to be moved.
+                print_error('cannotmovecate', 'question', $this->pageurl->out(), $newname);
+            }
             $tocontext = get_context_instance_by_id($tocontextid);
             require_capability('moodle/question:managecategory', $tocontext);
         }
+
+        // Update the category record.
         $cat = NULL;
         $cat->id = $updateid;
         $cat->name = $newname;
         $cat->info = $newinfo;
-        //never move category where it is the default
-        if (1 != $DB->count_records_sql("SELECT count(*)
-                                           FROM {question_categories} c1,
-                                                {question_categories} c2
-                                          WHERE c2.id = ?
-                                            AND c1.contextid = c2.contextid", array($updateid))){
-            // If the question name has changed, rename any random questions in that category.
-            if ($oldcat->name != $cat->name) {
-                $randomqname = $QTYPES[RANDOM]->question_name($cat);
-                $DB->set_field('question', 'name', $randomqname, array('category' => $cat->id), 'qtype', RANDOM);
-                // Ignore errors here. It is not a big deal if the questions are not renamed.
-            }
+        $cat->parent = $parentid;
+        // We don't change $cat->contextid here, if necessary we redirect to contextmove.php later.
+        if (!$DB->update_record('question_categories', $cat)) {
+            print_error('cannotupdatecate', 'question', $this->pageurl->out(), $newname);
+        }
 
-            // Then update the category itself.
-            if ($oldcat->contextid == $tocontextid){ // not moving contexts
-                $cat->parent = $parentid;
-                if (!$DB->update_record("question_categories", $cat)) {
-                    print_error('cannotupdatecate', 'question', $this->pageurl->out(), $newname);
-                } else {
-                    redirect($this->pageurl->out());
-                }
-            } else {
-                if (!$DB->update_record("question_categories", $cat)) {
-                    print_error('cannotupdatecate', 'question', $this->pageurl->out(), $newname);
-                } else {
-                    redirect($CFG->wwwroot.'/question/contextmove.php?'.
-                                $this->pageurl->get_query_string(array('cattomove' => $updateid,
-                                                                        'toparent'=>$newparent)));
-                }
-            }
+        // If the question name has changed, rename any random questions in that category.
+        if ($oldcat->name != $cat->name) {
+            $randomqname = $QTYPES[RANDOM]->question_name($cat);
+            $DB->set_field('question', 'name', $randomqname, array('category' => $cat->id), 'qtype', RANDOM);
+            // Ignore errors here. It is not a big deal if the questions are not renamed.
+        }
+
+        // Then redirect to an appropriate place.
+        if ($oldcat->contextid == $tocontextid) { // not moving contexts
+            redirect($this->pageurl->out());
         } else {
-            print_error('cannotmovecate', 'question', $this->pageurl->out(), $newname);
+            redirect($CFG->wwwroot.'/question/contextmove.php?' .
+                    $this->pageurl->get_query_string(array(
+                    'cattomove' => $updateid, 'toparent'=>$newparent)));
         }
     }
 
-- 
2.39.5