/**
 * Prints a forum discussion
 *
 * @uses CONTEXT_MODULE
 * @uses FORUM_MODE_FLATNEWEST
 * @uses FORUM_MODE_FLATOLDEST
 * @uses FORUM_MODE_THREADED
 * @uses FORUM_MODE_NESTED
 * @param stdClass $course
 * @param stdClass $cm
 * @param stdClass $forum
 * @param stdClass $discussion
 * @param stdClass $post
 * @param int $mode
 * @param mixed $canreply
 * @param bool $canrate
 */
function forum_print_discussion($course, $cm, $forum, $discussion, $post, $mode, $canreply=NULL, $canrate=false) {
    global $USER, $CFG;

    require_once($CFG->dirroot.'/rating/lib.php');

    $ownpost = (isloggedin() && $USER->id == $post->userid);

    $modcontext = context_module::instance($cm->id);
    if ($canreply === NULL) {
        $reply = forum_user_can_post($forum, $discussion, $USER, $cm, $course, $modcontext);
    } else {
        $reply = $canreply;
    }

    // $cm holds general cache for forum functions
    $cm->cache = new stdClass;
    $cm->cache->groups      = groups_get_all_groups($course->id, 0, $cm->groupingid);
    $cm->cache->usersgroups = array();

    $posters = array();

    // preload all posts - TODO: improve...
    if ($mode == FORUM_MODE_FLATNEWEST) {
        $sort = "p.created DESC";
    } else {
        $sort = "p.created ASC";
    }

    $forumtracked = forum_tp_is_tracked($forum);
    $posts = forum_get_all_discussion_posts($discussion->id, $sort, $forumtracked);
    $post = $posts[$post->id];

    foreach ($posts as $pid=>$p) {
        $posters[$p->userid] = $p->userid;
    }

    // preload all groups of ppl that posted in this discussion
    if ($postersgroups = groups_get_all_groups($course->id, $posters, $cm->groupingid, 'gm.id, gm.groupid, gm.userid')) {
        foreach($postersgroups as $pg) {
            if (!isset($cm->cache->usersgroups[$pg->userid])) {
                $cm->cache->usersgroups[$pg->userid] = array();
            }
            $cm->cache->usersgroups[$pg->userid][$pg->groupid] = $pg->groupid;
        }
        unset($postersgroups);
    }

    //load ratings
    if ($forum->assessed != RATING_AGGREGATE_NONE) {
        $ratingoptions = new stdClass;
        $ratingoptions->context = $modcontext;
        $ratingoptions->component = 'mod_forum';
        $ratingoptions->ratingarea = 'post';
        $ratingoptions->items = $posts;
        $ratingoptions->aggregate = $forum->assessed;//the aggregation method
        $ratingoptions->scaleid = $forum->scale;
        $ratingoptions->userid = $USER->id;
        if ($forum->type == 'single' or !$discussion->id) {
            $ratingoptions->returnurl = "$CFG->wwwroot/mod/forum/view.php?id=$cm->id";
        } else {
            $ratingoptions->returnurl = "$CFG->wwwroot/mod/forum/discuss.php?d=$discussion->id";
        }
        $ratingoptions->assesstimestart = $forum->assesstimestart;
        $ratingoptions->assesstimefinish = $forum->assesstimefinish;

        $rm = new rating_manager();
        $posts = $rm->get_ratings($ratingoptions);
    }


    $post->forum = $forum->id;   // Add the forum id to the post object, later used by forum_print_post
    $post->forumtype = $forum->type;

    $post->subject = format_string($post->subject);

    $postread = !empty($post->postread);

    forum_print_post($post, $discussion, $forum, $cm, $course, $ownpost, $reply, false,
                         '', '', $postread, true, $forumtracked);

    switch ($mode) {
        case FORUM_MODE_FLATOLDEST :
        case FORUM_MODE_FLATNEWEST :
//.........这里部分代码省略.........

     print_error('notpartofdiscussion', 'forum');
 }
 if (!($forum = $DB->get_record("forum", array("id" => $discussion->forum)))) {
     print_error('invalidforumid', 'forum');
 }
 if (!($course = $DB->get_record("course", array("id" => $discussion->course)))) {
     print_error('invalidcourseid');
 }
 if (!($cm = get_coursemodule_from_instance("forum", $forum->id, $course->id))) {
     print_error('invalidcoursemodule');
 }
 // Ensure lang, theme, etc. is set up properly. MDL-6926
 $PAGE->set_cm($cm, $course, $forum);
 $coursecontext = get_context_instance(CONTEXT_COURSE, $course->id);
 $modcontext = get_context_instance(CONTEXT_MODULE, $cm->id);
 if (!forum_user_can_post($forum, $discussion, $USER, $cm, $course, $modcontext)) {
     if (!isguestuser()) {
         if (!is_enrolled($coursecontext)) {
             // User is a guest here!
             $SESSION->wantsurl = $FULLME;
             $SESSION->enrolcancel = $_SERVER['HTTP_REFERER'];
             redirect($CFG->wwwroot . '/enrol/index.php?id=' . $course->id, get_string('youneedtoenrol'));
         }
     }
     print_error('nopostforum', 'forum');
 }
 // Make sure user can post here
 if (isset($cm->groupmode) && empty($course->groupmodeforce)) {
     $groupmode = $cm->groupmode;
 } else {
     $groupmode = $course->groupmode;

    $forumnode->make_active();
}
$node = $forumnode->add(format_string($discussion->name), new moodle_url('/mod/forum/discuss.php', array('d' => $discussion->id)));
$node->display = false;
if ($node && $post->id != $discussion->firstpost) {
    $node->add(format_string($post->subject), $PAGE->url);
}
$PAGE->set_title("{$course->shortname}: " . format_string($discussion->name));
$PAGE->set_heading($course->fullname);
$PAGE->set_button($searchform);
echo $OUTPUT->header();
echo $OUTPUT->heading(format_string($forum->name), 2);
/// Check to see if groups are being used in this forum
/// If so, make sure the current person is allowed to see this discussion
/// Also, if we know they should be able to reply, then explicitly set $canreply for performance reasons
$canreply = forum_user_can_post($forum, $discussion, $USER, $cm, $course, $modcontext);
if (!$canreply and $forum->type !== 'news') {
    if (isguestuser() or !isloggedin()) {
        $canreply = true;
    }
    if (!is_enrolled($modcontext) and !is_viewing($modcontext)) {
        // allow guests and not-logged-in to see the link - they are prompted to log in after clicking the link
        // normal users with temporary guest access see this link too, they are asked to enrol instead
        $canreply = enrol_selfenrol_available($course->id);
    }
}
/// Print the controls across the top
echo '<div class="discussioncontrols clearfix">';
if (!empty($CFG->enableportfolios) && has_capability('mod/forum:exportdiscussion', $modcontext)) {
    require_once $CFG->libdir . '/portfoliolib.php';
    $button = new portfolio_add_button();

 /**
  * Returns a list of forum posts for a discussion
  *
  * @param int $discussionid the post ids
  * @param string $sortby sort by this element (id, created or modified)
  * @param string $sortdirection sort direction: ASC or DESC
  *
  * @return array the forum post details
  * @since Moodle 2.7
  */
 public static function get_forum_discussion_posts($discussionid, $sortby = "created", $sortdirection = "DESC")
 {
     global $CFG, $DB, $USER;
     $warnings = array();
     // Validate the parameter.
     $params = self::validate_parameters(self::get_forum_discussion_posts_parameters(), array('discussionid' => $discussionid, 'sortby' => $sortby, 'sortdirection' => $sortdirection));
     // Compact/extract functions are not recommended.
     $discussionid = $params['discussionid'];
     $sortby = $params['sortby'];
     $sortdirection = $params['sortdirection'];
     $sortallowedvalues = array('id', 'created', 'modified');
     if (!in_array($sortby, $sortallowedvalues)) {
         throw new invalid_parameter_exception('Invalid value for sortby parameter (value: ' . $sortby . '),' . 'allowed values are: ' . implode(',', $sortallowedvalues));
     }
     $sortdirection = strtoupper($sortdirection);
     $directionallowedvalues = array('ASC', 'DESC');
     if (!in_array($sortdirection, $directionallowedvalues)) {
         throw new invalid_parameter_exception('Invalid value for sortdirection parameter (value: ' . $sortdirection . '),' . 'allowed values are: ' . implode(',', $directionallowedvalues));
     }
     $discussion = $DB->get_record('forum_discussions', array('id' => $discussionid), '*', MUST_EXIST);
     $forum = $DB->get_record('forum', array('id' => $discussion->forum), '*', MUST_EXIST);
     $course = $DB->get_record('course', array('id' => $forum->course), '*', MUST_EXIST);
     $cm = get_coursemodule_from_instance('forum', $forum->id, $course->id, false, MUST_EXIST);
     // Validate the module context. It checks everything that affects the module visibility (including groupings, etc..).
     $modcontext = context_module::instance($cm->id);
     self::validate_context($modcontext);
     // This require must be here, see mod/forum/discuss.php.
     require_once $CFG->dirroot . "/mod/forum/lib.php";
     // Check they have the view forum capability.
     require_capability('mod/forum:viewdiscussion', $modcontext, null, true, 'noviewdiscussionspermission', 'forum');
     if (!($post = forum_get_post_full($discussion->firstpost))) {
         throw new moodle_exception('notexists', 'forum');
     }
     // This function check groups, qanda, timed discussions, etc.
     if (!forum_user_can_see_post($forum, $discussion, $post, null, $cm)) {
         throw new moodle_exception('noviewdiscussionspermission', 'forum');
     }
     $canviewfullname = has_capability('moodle/site:viewfullnames', $modcontext);
     // We will add this field in the response.
     $canreply = forum_user_can_post($forum, $discussion, $USER, $cm, $course, $modcontext);
     $forumtracked = forum_tp_is_tracked($forum);
     $sort = 'p.' . $sortby . ' ' . $sortdirection;
     $posts = forum_get_all_discussion_posts($discussion->id, $sort, $forumtracked);
     foreach ($posts as $pid => $post) {
         if (!forum_user_can_see_post($forum, $discussion, $post, null, $cm)) {
             $warning = array();
             $warning['item'] = 'post';
             $warning['itemid'] = $post->id;
             $warning['warningcode'] = '1';
             $warning['message'] = 'You can\'t see this post';
             $warnings[] = $warning;
             continue;
         }
         // Function forum_get_all_discussion_posts adds postread field.
         // Note that the value returned can be a boolean or an integer. The WS expects a boolean.
         if (empty($post->postread)) {
             $posts[$pid]->postread = false;
         } else {
             $posts[$pid]->postread = true;
         }
         $posts[$pid]->canreply = $canreply;
         if (!empty($posts[$pid]->children)) {
             $posts[$pid]->children = array_keys($posts[$pid]->children);
         } else {
             $posts[$pid]->children = array();
         }
         $user = new stdclass();
         $user = username_load_fields_from_object($user, $post);
         $posts[$pid]->userfullname = fullname($user, $canviewfullname);
         $posts[$pid] = (array) $post;
     }
     $result = array();
     $result['posts'] = $posts;
     $result['warnings'] = $warnings;
     return $result;
 }

     error("This post is not part of a discussion!");
 }
 if (!($forum = get_record("forum", "id", $discussion->forum))) {
     error("The forum number was incorrect ({$discussion->forum})");
 }
 if (!($course = get_record("course", "id", $discussion->course))) {
     error("The course number was incorrect ({$discussion->course})");
 }
 if (!($cm = get_coursemodule_from_instance("forum", $forum->id, $course->id))) {
     error("Incorrect cm");
 }
 // call course_setup to use forced language, MDL-6926
 course_setup($course->id);
 $coursecontext = get_context_instance(CONTEXT_COURSE, $course->id);
 $modcontext = get_context_instance(CONTEXT_MODULE, $cm->id);
 if (!forum_user_can_post($forum)) {
     if (has_capability('moodle/legacy:guest', $coursecontext, NULL, false)) {
         // User is a guest here!
         $SESSION->wantsurl = $FULLME;
         $SESSION->enrolcancel = $_SERVER['HTTP_REFERER'];
         redirect($CFG->wwwroot . '/course/enrol.php?id=' . $course->id, get_string('youneedtoenrol'));
     } else {
         print_error('nopostforum', 'forum');
     }
 }
 if (groupmode($course, $cm)) {
     // Make sure user can post here
     $mygroupid = mygroupid($course->id);
     if (!((empty($mygroupid) and $discussion->groupid == -1) || ismember($discussion->groupid) || has_capability('moodle/site:accessallgroups', $modcontext, NULL, false))) {
         print_error('nopostdiscussion', 'forum');
     }

    /**
     * Create new posts into an existing discussion.
     *
     * @param int $postid the post id we are going to reply to
     * @param string $subject new post subject
     * @param string $message new post message (only html format allowed)
     * @param array $options optional settings
     * @return array of warnings and the new post id
     * @since Moodle 3.0
     * @throws moodle_exception
     */
    public static function add_discussion_post($postid, $subject, $message, $options = array()) {
        global $DB, $CFG, $USER;
        require_once($CFG->dirroot . "/mod/forum/lib.php");

        $params = self::validate_parameters(self::add_discussion_post_parameters(),
                                            array(
                                                'postid' => $postid,
                                                'subject' => $subject,
                                                'message' => $message,
                                                'options' => $options
                                            ));
        // Validate options.
        $options = array(
            'discussionsubscribe' => true
        );
        foreach ($params['options'] as $option) {
            $name = trim($option['name']);
            switch ($name) {
                case 'discussionsubscribe':
                    $value = clean_param($option['value'], PARAM_BOOL);
                    break;
                default:
                    throw new moodle_exception('errorinvalidparam', 'webservice', '', $name);
            }
            $options[$name] = $value;
        }

        $warnings = array();

        if (!$parent = forum_get_post_full($params['postid'])) {
            throw new moodle_exception('invalidparentpostid', 'forum');
        }

        if (!$discussion = $DB->get_record("forum_discussions", array("id" => $parent->discussion))) {
            throw new moodle_exception('notpartofdiscussion', 'forum');
        }

        // Request and permission validation.
        $forum = $DB->get_record('forum', array('id' => $discussion->forum), '*', MUST_EXIST);
        list($course, $cm) = get_course_and_cm_from_instance($forum, 'forum');

        $context = context_module::instance($cm->id);
        self::validate_context($context);

        if (!forum_user_can_post($forum, $discussion, $USER, $cm, $course, $context)) {
            throw new moodle_exception('nopostforum', 'forum');
        }

        $thresholdwarning = forum_check_throttling($forum, $cm);
        forum_check_blocking_threshold($thresholdwarning);

        // Create the post.
        $post = new stdClass();
        $post->discussion = $discussion->id;
        $post->parent = $parent->id;
        $post->subject = $params['subject'];
        $post->message = $params['message'];
        $post->messageformat = FORMAT_HTML;   // Force formatting for now.
        $post->messagetrust = trusttext_trusted($context);
        $post->itemid = 0;

        if ($postid = forum_add_new_post($post, null)) {

            $post->id = $postid;

            // Trigger events and completion.
            $params = array(
                'context' => $context,
                'objectid' => $post->id,
                'other' => array(
                    'discussionid' => $discussion->id,
                    'forumid' => $forum->id,
                    'forumtype' => $forum->type,
                )
            );
            $event = \mod_forum\event\post_created::create($params);
            $event->add_record_snapshot('forum_posts', $post);
            $event->add_record_snapshot('forum_discussions', $discussion);
            $event->trigger();

            // Update completion state.
            $completion = new completion_info($course);
            if ($completion->is_enabled($cm) &&
                    ($forum->completionreplies || $forum->completionposts)) {
                $completion->update_state($cm, COMPLETION_COMPLETE);
            }

            $settings = new stdClass();
            $settings->discussionsubscribe = $options['discussionsubscribe'];
//.........这里部分代码省略.........

    /**
     * Process a message received and validated by the Inbound Message processor.
     *
     * @throws \core\message\inbound\processing_failed_exception
     * @param \stdClass $messagedata The Inbound Message record
     * @param \stdClass $messagedata The message data packet
     * @return bool Whether the message was successfully processed.
     */
    public function process_message(\stdClass $record, \stdClass $messagedata) {
        global $DB, $USER;

        // Load the post being replied to.
        $post = $DB->get_record('forum_posts', array('id' => $record->datavalue));
        if (!$post) {
            mtrace("--> Unable to find a post matching with id {$record->datavalue}");
            return false;
        }

        // Load the discussion that this post is in.
        $discussion = $DB->get_record('forum_discussions', array('id' => $post->discussion));
        if (!$post) {
            mtrace("--> Unable to find the discussion for post {$record->datavalue}");
            return false;
        }

        // Load the other required data.
        $forum = $DB->get_record('forum', array('id' => $discussion->forum));
        $course = $DB->get_record('course', array('id' => $forum->course));
        $cm = get_fast_modinfo($course->id)->instances['forum'][$forum->id];
        $modcontext = \context_module::instance($cm->id);
        $usercontext = \context_user::instance($USER->id);

        // Make sure user can post in this discussion.
        $canpost = true;
        if (!forum_user_can_post($forum, $discussion, $USER, $cm, $course, $modcontext)) {
            $canpost = false;
        }

        if (isset($cm->groupmode) && empty($course->groupmodeforce)) {
            $groupmode = $cm->groupmode;
        } else {
            $groupmode = $course->groupmode;
        }
        if ($groupmode == SEPARATEGROUPS and !has_capability('moodle/site:accessallgroups', $modcontext)) {
            if ($discussion->groupid == -1) {
                $canpost = false;
            } else {
                if (!groups_is_member($discussion->groupid)) {
                    $canpost = false;
                }
            }
        }

        if (!$canpost) {
            $data = new \stdClass();
            $data->forum = $forum;
            throw new \core\message\inbound\processing_failed_exception('messageinboundnopostforum', 'mod_forum', $data);
        }

        // And check the availability.
        if (!\core_availability\info_module::is_user_visible($cm, $USER, true)) {
            $data = new \stdClass();
            $data->forum = $forum;
            throw new \core\message\inbound\processing_failed_exception('messageinboundforumhidden', 'mod_forum', $data);
        }

        // Before we add this we must check that the user will not exceed the blocking threshold.
        // This should result in an appropriate reply.
        $thresholdwarning = forum_check_throttling($forum, $cm);
        if (!empty($thresholdwarning) && !$thresholdwarning->canpost) {
            $data = new \stdClass();
            $data->forum = $forum;
            $data->message = get_string($thresholdwarning->errorcode, $thresholdwarning->module, $thresholdwarning->additional);
            throw new \core\message\inbound\processing_failed_exception('messageinboundthresholdhit', 'mod_forum', $data);
        }

        $addpost = new \stdClass();
        $addpost->course       = $course->id;
        $addpost->forum        = $forum->id;
        $addpost->discussion   = $discussion->id;
        $addpost->modified     = $messagedata->timestamp;
        $addpost->subject      = clean_param($messagedata->envelope->subject, PARAM_TEXT);
        $addpost->parent       = $post->id;
        $addpost->itemid       = file_get_unused_draft_itemid();

        if (!empty($messagedata->html)) {
            $addpost->message = $messagedata->html;
            $addpost->messageformat = FORMAT_HTML;
        } else {
            $addpost->message = $messagedata->plain;
            $addpost->messageformat = FORMAT_PLAIN;
        }

        // We don't trust text coming from e-mail.
        $addpost->messagetrust = false;

        // Add attachments to the post.
        if (!empty($messagedata->attachments['attachment']) && count($messagedata->attachments['attachment'])) {
            $attachmentcount = count($messagedata->attachments['attachment']);
            if (empty($forum->maxattachments) || $forum->maxbytes == 1 ||
//.........这里部分代码省略.........

/**
 *
 */
function forum_print_discussion($course, $cm, $forum, $discussion, $post, $mode, $canreply = NULL, $canrate = false)
{
    global $USER, $CFG;
    if (!empty($USER->id)) {
        $ownpost = $USER->id == $post->userid;
    } else {
        $ownpost = false;
    }
    if ($canreply === NULL) {
        $modcontext = get_context_instance(CONTEXT_MODULE, $cm->id);
        $reply = forum_user_can_post($forum, $discussion, $USER, $cm, $course, $modcontext);
    } else {
        $reply = $canreply;
    }
    // $cm holds general cache for forum functions
    $cm->cache = new object();
    $cm->cache->groups = groups_get_all_groups($course->id, 0, $cm->groupingid);
    $cm->cache->usersgroups = array();
    $posters = array();
    // preload all posts - TODO: improve...
    if ($mode == FORUM_MODE_FLATNEWEST) {
        $sort = "p.created DESC";
    } else {
        $sort = "p.created ASC";
    }
    $forumtracked = forum_tp_is_tracked($forum);
    $posts = forum_get_all_discussion_posts($discussion->id, $sort, $forumtracked);
    $post = $posts[$post->id];
    foreach ($posts as $pid => $p) {
        $posters[$p->userid] = $p->userid;
    }
    // preload all groups of ppl that posted in this discussion
    if ($postersgroups = groups_get_all_groups($course->id, $posters, $cm->groupingid, 'gm.id, gm.groupid, gm.userid')) {
        foreach ($postersgroups as $pg) {
            if (!isset($cm->cache->usersgroups[$pg->userid])) {
                $cm->cache->usersgroups[$pg->userid] = array();
            }
            $cm->cache->usersgroups[$pg->userid][$pg->groupid] = $pg->groupid;
        }
        unset($postersgroups);
    }
    $ratings = NULL;
    $ratingsmenuused = false;
    $ratingsformused = false;
    if ($forum->assessed and isloggedin()) {
        if ($ratings->scale = make_grades_menu($forum->scale)) {
            $ratings->assesstimestart = $forum->assesstimestart;
            $ratings->assesstimefinish = $forum->assesstimefinish;
            $ratings->allow = $canrate;
            if ($ratings->allow) {
                echo '<form id="form" method="post" action="rate.php">';
                echo '<div class="ratingform">';
                echo '<input type="hidden" name="forumid" value="' . $forum->id . '" />';
                $ratingsformused = true;
            }
            // preload all ratings - one query only and minimal memory
            $cm->cache->ratings = array();
            $cm->cache->myratings = array();
            if ($postratings = forum_get_all_discussion_ratings($discussion)) {
                foreach ($postratings as $pr) {
                    if (!isset($cm->cache->ratings[$pr->postid])) {
                        $cm->cache->ratings[$pr->postid] = array();
                    }
                    $cm->cache->ratings[$pr->postid][$pr->id] = $pr->rating;
                    if ($pr->userid == $USER->id) {
                        $cm->cache->myratings[$pr->postid] = $pr->rating;
                    }
                }
                unset($postratings);
            }
        }
    }
    $post->forum = $forum->id;
    // Add the forum id to the post object, later used by forum_print_post
    $post->forumtype = $forum->type;
    $post->subject = format_string($post->subject);
    $postread = !empty($post->postread);
    if (forum_print_post($post, $discussion, $forum, $cm, $course, $ownpost, $reply, false, $ratings, '', '', $postread, true, $forumtracked)) {
        $ratingsmenuused = true;
    }
    switch ($mode) {
        case FORUM_MODE_FLATOLDEST:
        case FORUM_MODE_FLATNEWEST:
        default:
            if (forum_print_posts_flat($course, $cm, $forum, $discussion, $post, $mode, $ratings, $reply, $forumtracked, $posts)) {
                $ratingsmenuused = true;
            }
            break;
        case FORUM_MODE_THREADED:
            if (forum_print_posts_threaded($course, $cm, $forum, $discussion, $post, 0, $ratings, $reply, $forumtracked, $posts)) {
                $ratingsmenuused = true;
            }
            break;
        case FORUM_MODE_NESTED:
            if (forum_print_posts_nested($course, $cm, $forum, $discussion, $post, $ratings, $reply, $forumtracked, $posts)) {
                $ratingsmenuused = true;
            }
//.........这里部分代码省略.........

/**
 * Builds and returns the body of the email notification in html format.
 *
 * @param object $course
 * @param object $cm
 * @param object $forum
 * @param object $discussion
 * @param object $post
 * @param object $userfrom
 * @param object $userto
 * @param string $replyaddress The inbound address that a user can reply to the generated e-mail with. [Since 2.8].
 * @return string The email text in HTML format
 * @deprecated since Moodle 3.0 use \mod_forum\output\forum_post_email instead
 */
function forum_make_mail_html($course, $cm, $forum, $discussion, $post, $userfrom, $userto, $replyaddress = null)
{
    return forum_make_mail_post($course, $cm, $forum, $discussion, $post, $userfrom, $userto, forum_user_can_post($forum, $discussion, $userto, $cm, $course));
}