From 2256bb74afcbd2babf0b5768f7a359997e6f6299 Mon Sep 17 00:00:00 2001
From: Juan Leyva <juanleyvadelgado@gmail.com>
Date: Thu, 30 Mar 2017 11:55:38 +0200
Subject: [PATCH] MDL-58444 mod_forum: Return number of unread posts in WS

---
 mod/forum/externallib.php            |  5 +++++
 mod/forum/lib.php                    |  7 ++++++-
 mod/forum/tests/externallib_test.php | 22 ++++++++++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/mod/forum/externallib.php b/mod/forum/externallib.php
index 04cde18a1d8..a6745c2a6d8 100644
--- a/mod/forum/externallib.php
+++ b/mod/forum/externallib.php
@@ -98,6 +98,9 @@ class mod_forum_external extends external_api {
                 $forum->cmid = $forum->coursemodule;
                 $forum->cancreatediscussions = forum_user_can_post_discussion($forum, null, -1, $cm, $context);
                 $forum->istracked = forum_tp_is_tracked($forum);
+                if ($forum->istracked) {
+                    $forum->unreadpostscount = forum_tp_count_forum_unread_posts($cm, $course);
+                }
 
                 // Add the forum to the array to return.
                 $arrforums[$forum->id] = $forum;
@@ -146,6 +149,8 @@ class mod_forum_external extends external_api {
                     'cancreatediscussions' => new external_value(PARAM_BOOL, 'If the user can create discussions', VALUE_OPTIONAL),
                     'lockdiscussionafter' => new external_value(PARAM_INT, 'After what period a discussion is locked', VALUE_OPTIONAL),
                     'istracked' => new external_value(PARAM_BOOL, 'If the user is tracking the forum', VALUE_OPTIONAL),
+                    'unreadpostscount' => new external_value(PARAM_INT, 'The number of unread posts for tracked forums',
+                        VALUE_OPTIONAL),
                 ), 'forum'
             )
         );
diff --git a/mod/forum/lib.php b/mod/forum/lib.php
index 8c5ec559005..f1d3ee24d91 100644
--- a/mod/forum/lib.php
+++ b/mod/forum/lib.php
@@ -6360,13 +6360,18 @@ function forum_tp_get_course_unread_posts($userid, $courseid) {
  * @global object
  * @param object $cm
  * @param object $course
+ * @param bool   $resetreadcache optional, true to reset the function static $readcache var
  * @return int
  */
-function forum_tp_count_forum_unread_posts($cm, $course) {
+function forum_tp_count_forum_unread_posts($cm, $course, $resetreadcache = false) {
     global $CFG, $USER, $DB;
 
     static $readcache = array();
 
+    if ($resetreadcache) {
+        $readcache = array();
+    }
+
     $forumid = $cm->instance;
 
     if (!isset($readcache[$course->id])) {
diff --git a/mod/forum/tests/externallib_test.php b/mod/forum/tests/externallib_test.php
index ea1ca6d0354..3726b342892 100644
--- a/mod/forum/tests/externallib_test.php
+++ b/mod/forum/tests/externallib_test.php
@@ -94,6 +94,7 @@ class mod_forum_external_testcase extends externallib_advanced_testcase {
         $forum1->numdiscussions = 1;
         $forum1->cancreatediscussions = true;
         $forum1->istracked = true;
+        $forum1->unreadpostscount = 0;
         $forum1->introfiles = [];
 
         $record = new stdClass();
@@ -215,6 +216,7 @@ class mod_forum_external_testcase extends externallib_advanced_testcase {
         $record = new stdClass();
         $record->course = $course1->id;
         $forum2 = self::getDataGenerator()->create_module('forum', $record);
+        $forum2cm = get_coursemodule_from_id('forum', $forum2->cmid);
         $forum2context = context_module::instance($forum2->cmid);
 
         // Add discussions to the forums.
@@ -352,6 +354,16 @@ class mod_forum_external_testcase extends externallib_advanced_testcase {
         array_pop($posts['posts']);
         $this->assertEquals($expectedposts, $posts);
 
+        // Check we receive the unread count correctly on tracked forum.
+        forum_tp_count_forum_unread_posts($forum2cm, $course1, true);    // Reset static cache.
+        $result = mod_forum_external::get_forums_by_courses(array($course1->id));
+        $result = external_api::clean_returnvalue(mod_forum_external::get_forums_by_courses_returns(), $result);
+        foreach ($result as $f) {
+            if ($f['id'] == $forum2->id) {
+                $this->assertEquals(1, $f['unreadpostscount']);
+            }
+        }
+
         // Test discussion without additional posts. There should be only one post (the one created by the discussion).
         $posts = mod_forum_external::get_forum_discussion_posts($discussion2->id, 'modified', 'DESC');
         $posts = external_api::clean_returnvalue(mod_forum_external::get_forum_discussion_posts_returns(), $posts);
@@ -382,6 +394,16 @@ class mod_forum_external_testcase extends externallib_advanced_testcase {
         foreach ($posts['posts'] as $post) {
             $this->assertTrue($post['postread']);
         }
+
+        // Check we receive 0 unread posts.
+        forum_tp_count_forum_unread_posts($forum2cm, $course1, true);    // Reset static cache.
+        $result = mod_forum_external::get_forums_by_courses(array($course1->id));
+        $result = external_api::clean_returnvalue(mod_forum_external::get_forums_by_courses_returns(), $result);
+        foreach ($result as $f) {
+            if ($f['id'] == $forum2->id) {
+                $this->assertEquals(0, $f['unreadpostscount']);
+            }
+        }
     }
 
     /**