1<?php
2// This file is part of Moodle - http://moodle.org/
3//
4// Moodle is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// Moodle is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13//
14// You should have received a copy of the GNU General Public License
15// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
16
17/**
18 * Core global functions for Blog.
19 *
20 * @package    moodlecore
21 * @subpackage blog
22 * @copyright  2009 Nicolas Connault
23 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
24 */
25
26defined('MOODLE_INTERNAL') || die();
27
28/*
29 * Library of functions and constants for blog
30 */
31require_once($CFG->dirroot .'/blog/rsslib.php');
32
33/**
34 * User can edit a blog entry if this is their own blog entry and they have
35 * the capability moodle/blog:create, or if they have the capability
36 * moodle/blog:manageentries.
37 *
38 * This also applies to deleting of entries.
39 */
40function blog_user_can_edit_entry($blogentry) {
41    global $USER;
42
43    $sitecontext = context_system::instance();
44
45    if (has_capability('moodle/blog:manageentries', $sitecontext)) {
46        return true; // Can edit any blog entry.
47    }
48
49    if ($blogentry->userid == $USER->id && has_capability('moodle/blog:create', $sitecontext)) {
50        return true; // Can edit own when having blog:create capability.
51    }
52
53    return false;
54}
55
56
57/**
58 * Checks to see if a user can view the blogs of another user.
59 * Only blog level is checked here, the capabilities are enforced
60 * in blog/index.php
61 */
62function blog_user_can_view_user_entry($targetuserid, $blogentry=null) {
63    global $CFG, $USER, $DB;
64
65    if (empty($CFG->enableblogs)) {
66        return false; // Blog system disabled.
67    }
68
69    if (isloggedin() && $USER->id == $targetuserid) {
70        return true; // Can view own entries in any case.
71    }
72
73    $sitecontext = context_system::instance();
74    if (has_capability('moodle/blog:manageentries', $sitecontext)) {
75        return true; // Can manage all entries.
76    }
77
78    // If blog is in draft state, then make sure user have proper capability.
79    if ($blogentry && $blogentry->publishstate == 'draft' && !has_capability('moodle/blog:viewdrafts', $sitecontext)) {
80        return false;  // Can not view draft of others.
81    }
82
83    // If blog entry is not public, make sure user is logged in.
84    if ($blogentry && $blogentry->publishstate != 'public' && !isloggedin()) {
85        return false;
86    }
87
88    // If blogentry is not passed or all above checks pass, then check capability based on system config.
89    switch ($CFG->bloglevel) {
90        case BLOG_GLOBAL_LEVEL:
91            return true;
92        break;
93
94        case BLOG_SITE_LEVEL:
95            if (isloggedin()) { // Not logged in viewers forbidden.
96                return true;
97            }
98            return false;
99        break;
100
101        case BLOG_USER_LEVEL:
102        default:
103            // If user is viewing other user blog, then user should have user:readuserblogs capability.
104            $personalcontext = context_user::instance($targetuserid);
105            return has_capability('moodle/user:readuserblogs', $personalcontext);
106        break;
107
108    }
109}
110
111/**
112 * remove all associations for the blog entries of a particular user
113 * @param int userid - id of user whose blog associations will be deleted
114 */
115function blog_remove_associations_for_user($userid) {
116    global $DB;
117    throw new coding_exception('function blog_remove_associations_for_user() is not finished');
118    /*
119    $blogentries = blog_fetch_entries(array('user' => $userid), 'lasmodified DESC');
120    foreach ($blogentries as $entry) {
121        if (blog_user_can_edit_entry($entry)) {
122            blog_remove_associations_for_entry($entry->id);
123        }
124    }
125     */
126}
127
128/**
129 * remove all associations for the blog entries of a particular course
130 * @param int courseid - id of user whose blog associations will be deleted
131 */
132function blog_remove_associations_for_course($courseid) {
133    global $DB;
134    $context = context_course::instance($courseid);
135    $DB->delete_records('blog_association', array('contextid' => $context->id));
136}
137
138/**
139 * Remove module associated blogs and blog tag instances.
140 *
141 * @param  int $modcontextid Module context ID.
142 */
143function blog_remove_associations_for_module($modcontextid) {
144    global $DB;
145
146    if (!empty($assocblogids = $DB->get_fieldset_select('blog_association', 'blogid',
147        'contextid = :contextid', ['contextid' => $modcontextid]))) {
148        list($sql, $params) = $DB->get_in_or_equal($assocblogids, SQL_PARAMS_NAMED);
149
150        $DB->delete_records_select('tag_instance', "itemid $sql", $params);
151        $DB->delete_records_select('post', "id $sql AND module = :module",
152            array_merge($params, ['module' => 'blog']));
153        $DB->delete_records('blog_association', ['contextid' => $modcontextid]);
154    }
155}
156
157/**
158 * Given a record in the {blog_external} table, checks the blog's URL
159 * for new entries not yet copied into Moodle.
160 * Also attempts to identify and remove deleted blog entries
161 *
162 * @param object $externalblog
163 * @return boolean False if the Feed is invalid
164 */
165function blog_sync_external_entries($externalblog) {
166    global $CFG, $DB;
167    require_once($CFG->libdir . '/simplepie/moodle_simplepie.php');
168
169    $rss = new moodle_simplepie();
170    $rssfile = $rss->registry->create('File', array($externalblog->url));
171    $filetest = $rss->registry->create('Locator', array($rssfile));
172
173    if (!$filetest->is_feed($rssfile)) {
174        $externalblog->failedlastsync = 1;
175        $DB->update_record('blog_external', $externalblog);
176        return false;
177    } else if (!empty($externalblog->failedlastsync)) {
178        $externalblog->failedlastsync = 0;
179        $DB->update_record('blog_external', $externalblog);
180    }
181
182    $rss->set_feed_url($externalblog->url);
183    $rss->init();
184
185    if (empty($rss->data)) {
186        return null;
187    }
188    // Used to identify blog posts that have been deleted from the source feed.
189    $oldesttimestamp = null;
190    $uniquehashes = array();
191
192    foreach ($rss->get_items() as $entry) {
193        // If filtertags are defined, use them to filter the entries by RSS category.
194        if (!empty($externalblog->filtertags)) {
195            $containsfiltertag = false;
196            $categories = $entry->get_categories();
197            $filtertags = explode(',', $externalblog->filtertags);
198            $filtertags = array_map('trim', $filtertags);
199            $filtertags = array_map('strtolower', $filtertags);
200
201            if (!empty($categories)) {
202                foreach ($categories as $category) {
203                    if (in_array(trim(strtolower($category->term)), $filtertags)) {
204                        $containsfiltertag = true;
205                    }
206                }
207            }
208
209            if (!$containsfiltertag) {
210                continue;
211            }
212        }
213
214        $uniquehashes[] = $entry->get_permalink();
215
216        $newentry = new stdClass();
217        $newentry->userid = $externalblog->userid;
218        $newentry->module = 'blog_external';
219        $newentry->content = $externalblog->id;
220        $newentry->uniquehash = $entry->get_permalink();
221        $newentry->publishstate = 'site';
222        $newentry->format = FORMAT_HTML;
223        // Clean subject of html, just in case.
224        $newentry->subject = clean_param($entry->get_title(), PARAM_TEXT);
225        // Observe 128 max chars in DB.
226        // TODO: +1 to raise this to 255.
227        if (core_text::strlen($newentry->subject) > 128) {
228            $newentry->subject = core_text::substr($newentry->subject, 0, 125) . '...';
229        }
230        $newentry->summary = $entry->get_description();
231
232        // Used to decide whether to insert or update.
233        // Uses enty permalink plus creation date if available.
234        $existingpostconditions = array('uniquehash' => $entry->get_permalink());
235
236        // Our DB doesnt allow null creation or modified timestamps so check the external blog supplied one.
237        $entrydate = $entry->get_date('U');
238        if (!empty($entrydate)) {
239            $existingpostconditions['created'] = $entrydate;
240        }
241
242        // The post ID or false if post not found in DB.
243        $postid = $DB->get_field('post', 'id', $existingpostconditions);
244
245        $timestamp = null;
246        if (empty($entrydate)) {
247            $timestamp = time();
248        } else {
249            $timestamp = $entrydate;
250        }
251
252        // Only set created if its a new post so we retain the original creation timestamp if the post is edited.
253        if ($postid === false) {
254            $newentry->created = $timestamp;
255        }
256        $newentry->lastmodified = $timestamp;
257
258        if (empty($oldesttimestamp) || $timestamp < $oldesttimestamp) {
259            // Found an older post.
260            $oldesttimestamp = $timestamp;
261        }
262
263        if (core_text::strlen($newentry->uniquehash) > 255) {
264            // The URL for this item is too long for the field. Rather than add
265            // the entry without the link we will skip straight over it.
266            // RSS spec says recommended length 500, we use 255.
267            debugging('External blog entry skipped because of oversized URL', DEBUG_DEVELOPER);
268            continue;
269        }
270
271        if ($postid === false) {
272            $id = $DB->insert_record('post', $newentry);
273
274            // Set tags.
275            if ($tags = core_tag_tag::get_item_tags_array('core', 'blog_external', $externalblog->id)) {
276                core_tag_tag::set_item_tags('core', 'post', $id, context_user::instance($externalblog->userid), $tags);
277            }
278        } else {
279            $newentry->id = $postid;
280            $DB->update_record('post', $newentry);
281        }
282    }
283
284    // Look at the posts we have in the database to check if any of them have been deleted from the feed.
285    // Only checking posts within the time frame returned by the rss feed. Older items may have been deleted or
286    // may just not be returned anymore. We can't tell the difference so we leave older posts alone.
287    $sql = "SELECT id, uniquehash
288              FROM {post}
289             WHERE module = 'blog_external'
290                   AND " . $DB->sql_compare_text('content') . " = " . $DB->sql_compare_text(':blogid') . "
291                   AND created > :ts";
292    $dbposts = $DB->get_records_sql($sql, array('blogid' => $externalblog->id, 'ts' => $oldesttimestamp));
293
294    $todelete = array();
295    foreach ($dbposts as $dbpost) {
296        if ( !in_array($dbpost->uniquehash, $uniquehashes) ) {
297            $todelete[] = $dbpost->id;
298        }
299    }
300    $DB->delete_records_list('post', 'id', $todelete);
301
302    $DB->update_record('blog_external', array('id' => $externalblog->id, 'timefetched' => time()));
303}
304
305/**
306 * Given an external blog object, deletes all related blog entries from the post table.
307 * NOTE: The external blog's id is saved as post.content, a field that is not oterhwise used by blog entries.
308 * @param object $externablog
309 */
310function blog_delete_external_entries($externalblog) {
311    global $DB;
312    require_capability('moodle/blog:manageexternal', context_system::instance());
313    $DB->delete_records_select('post',
314                               "module='blog_external' AND " . $DB->sql_compare_text('content') . " = ?",
315                               array($externalblog->id));
316}
317
318/**
319 * This function checks that blogs are enabled, and that the user can see blogs at all
320 * @return bool
321 */
322function blog_is_enabled_for_user() {
323    global $CFG;
324    return (!empty($CFG->enableblogs) && (isloggedin() || ($CFG->bloglevel == BLOG_GLOBAL_LEVEL)));
325}
326
327/**
328 * This function gets all of the options available for the current user in respect
329 * to blogs.
330 *
331 * It loads the following if applicable:
332 * -  Module options {@see blog_get_options_for_module}
333 * -  Course options {@see blog_get_options_for_course}
334 * -  User specific options {@see blog_get_options_for_user}
335 * -  General options (BLOG_LEVEL_GLOBAL)
336 *
337 * @param moodle_page $page The page to load for (normally $PAGE)
338 * @param stdClass $userid Load for a specific user
339 * @return array An array of options organised by type.
340 */
341function blog_get_all_options(moodle_page $page, stdClass $userid = null) {
342    global $CFG, $DB, $USER;
343
344    $options = array();
345
346    // If blogs are enabled and the user is logged in and not a guest.
347    if (blog_is_enabled_for_user()) {
348        // If the context is the user then assume we want to load for the users context.
349        if (is_null($userid) && $page->context->contextlevel == CONTEXT_USER) {
350            $userid = $page->context->instanceid;
351        }
352        // Check the userid var.
353        if (!is_null($userid) && $userid !== $USER->id) {
354            // Load the user from the userid... it MUST EXIST throw a wobbly if it doesn't!
355            $user = $DB->get_record('user', array('id' => $userid), '*', MUST_EXIST);
356        } else {
357            $user = null;
358        }
359
360        if ($CFG->useblogassociations && $page->cm !== null) {
361            // Load for the module associated with the page.
362            $options[CONTEXT_MODULE] = blog_get_options_for_module($page->cm, $user);
363        } else if ($CFG->useblogassociations && $page->course->id != SITEID) {
364            // Load the options for the course associated with the page.
365            $options[CONTEXT_COURSE] = blog_get_options_for_course($page->course, $user);
366        }
367
368        // Get the options for the user.
369        if ($user !== null and !isguestuser($user)) {
370            // Load for the requested user.
371            $options[CONTEXT_USER + 1] = blog_get_options_for_user($user);
372        }
373        // Load for the current user.
374        if (isloggedin() and !isguestuser()) {
375            $options[CONTEXT_USER] = blog_get_options_for_user();
376        }
377    }
378
379    // If blog level is global then display a link to view all site entries.
380    if (!empty($CFG->enableblogs)
381        && $CFG->bloglevel >= BLOG_GLOBAL_LEVEL
382        && has_capability('moodle/blog:view', context_system::instance())) {
383
384        $options[CONTEXT_SYSTEM] = array('viewsite' => array(
385            'string' => get_string('viewsiteentries', 'blog'),
386            'link' => new moodle_url('/blog/index.php')
387        ));
388    }
389
390    // Return the options.
391    return $options;
392}
393
394/**
395 * Get all of the blog options that relate to the passed user.
396 *
397 * If no user is passed the current user is assumed.
398 *
399 * @staticvar array $useroptions Cache so we don't have to regenerate multiple times
400 * @param stdClass $user
401 * @return array The array of options for the requested user
402 */
403function blog_get_options_for_user(stdClass $user=null) {
404    global $CFG, $USER;
405    // Cache.
406    static $useroptions = array();
407
408    $options = array();
409    // Blogs must be enabled and the user must be logged in.
410    if (!blog_is_enabled_for_user()) {
411        return $options;
412    }
413
414    // Sort out the user var.
415    if ($user === null || $user->id == $USER->id) {
416        $user = $USER;
417        $iscurrentuser = true;
418    } else {
419        $iscurrentuser = false;
420    }
421
422    // If we've already generated serve from the cache.
423    if (array_key_exists($user->id, $useroptions)) {
424        return $useroptions[$user->id];
425    }
426
427    $sitecontext = context_system::instance();
428    $canview = has_capability('moodle/blog:view', $sitecontext);
429
430    if (!$iscurrentuser && $canview && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
431        // Not the current user, but we can view and its blogs are enabled for SITE or GLOBAL.
432        $options['userentries'] = array(
433            'string' => get_string('viewuserentries', 'blog', fullname($user)),
434            'link' => new moodle_url('/blog/index.php', array('userid' => $user->id))
435        );
436    } else {
437        // It's the current user.
438        if ($canview) {
439            // We can view our own blogs .... BIG surprise.
440            $options['view'] = array(
441                'string' => get_string('blogentries', 'blog'),
442                'link' => new moodle_url('/blog/index.php', array('userid' => $USER->id))
443            );
444        }
445        if (has_capability('moodle/blog:create', $sitecontext)) {
446            // We can add to our own blog.
447            $options['add'] = array(
448                'string' => get_string('addnewentry', 'blog'),
449                'link' => new moodle_url('/blog/edit.php', array('action' => 'add'))
450            );
451        }
452    }
453    if ($canview && $CFG->enablerssfeeds) {
454        $options['rss'] = array(
455            'string' => get_string('rssfeed', 'blog'),
456            'link' => new moodle_url(rss_get_url($sitecontext->id, $USER->id, 'blog', 'user/'.$user->id))
457        );
458    }
459
460    // Cache the options.
461    $useroptions[$user->id] = $options;
462    // Return the options.
463    return $options;
464}
465
466/**
467 * Get the blog options that relate to the given course for the given user.
468 *
469 * @staticvar array $courseoptions A cache so we can save regenerating multiple times
470 * @param stdClass $course The course to load options for
471 * @param stdClass $user The user to load options for null == current user
472 * @return array The array of options
473 */
474function blog_get_options_for_course(stdClass $course, stdClass $user=null) {
475    global $CFG, $USER;
476    // Cache.
477    static $courseoptions = array();
478
479    $options = array();
480
481    // User must be logged in and blogs must be enabled.
482    if (!blog_is_enabled_for_user()) {
483        return $options;
484    }
485
486    // Check that the user can associate with the course.
487    $sitecontext = context_system::instance();
488    // Generate the cache key.
489    $key = $course->id.':';
490    if (!empty($user)) {
491        $key .= $user->id;
492    } else {
493        $key .= $USER->id;
494    }
495    // Serve from the cache if we've already generated for this course.
496    if (array_key_exists($key, $courseoptions)) {
497        return $courseoptions[$key];
498    }
499
500    if (has_capability('moodle/blog:view', $sitecontext)) {
501        // We can view!
502        if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
503            // View entries about this course.
504            $options['courseview'] = array(
505                'string' => get_string('viewcourseblogs', 'blog'),
506                'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id))
507            );
508        }
509        // View MY entries about this course.
510        $options['courseviewmine'] = array(
511            'string' => get_string('viewmyentriesaboutcourse', 'blog'),
512            'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id, 'userid' => $USER->id))
513        );
514        if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
515            // View the provided users entries about this course.
516            $options['courseviewuser'] = array(
517                'string' => get_string('viewentriesbyuseraboutcourse', 'blog', fullname($user)),
518                'link' => new moodle_url('/blog/index.php', array('courseid' => $course->id, 'userid' => $user->id))
519            );
520        }
521    }
522
523    if (has_capability('moodle/blog:create', $sitecontext)) {
524        // We can blog about this course.
525        $options['courseadd'] = array(
526            'string' => get_string('blogaboutthiscourse', 'blog'),
527            'link' => new moodle_url('/blog/edit.php', array('action' => 'add', 'courseid' => $course->id))
528        );
529    }
530
531    // Cache the options for this course.
532    $courseoptions[$key] = $options;
533    // Return the options.
534    return $options;
535}
536
537/**
538 * Get the blog options relating to the given module for the given user
539 *
540 * @staticvar array $moduleoptions Cache
541 * @param stdClass|cm_info $module The module to get options for
542 * @param stdClass $user The user to get options for null == currentuser
543 * @return array
544 */
545function blog_get_options_for_module($module, $user=null) {
546    global $CFG, $USER;
547    // Cache.
548    static $moduleoptions = array();
549
550    $options = array();
551    // User must be logged in, blogs must be enabled.
552    if (!blog_is_enabled_for_user()) {
553        return $options;
554    }
555
556    $sitecontext = context_system::instance();
557
558    // Generate the cache key.
559    $key = $module->id.':';
560    if (!empty($user)) {
561        $key .= $user->id;
562    } else {
563        $key .= $USER->id;
564    }
565    if (array_key_exists($key, $moduleoptions)) {
566        // Serve from the cache so we don't have to regenerate.
567        return $moduleoptions[$key];
568    }
569
570    if (has_capability('moodle/blog:view', $sitecontext)) {
571        // Save correct module name for later usage.
572        $modulename = get_string('modulename', $module->modname);
573
574        // We can view!
575        if ($CFG->bloglevel >= BLOG_SITE_LEVEL) {
576            // View all entries about this module.
577            $a = new stdClass;
578            $a->type = $modulename;
579            $options['moduleview'] = array(
580                'string' => get_string('viewallmodentries', 'blog', $a),
581                'link' => new moodle_url('/blog/index.php', array('modid' => $module->id))
582            );
583        }
584        // View MY entries about this module.
585        $options['moduleviewmine'] = array(
586            'string' => get_string('viewmyentriesaboutmodule', 'blog', $modulename),
587            'link' => new moodle_url('/blog/index.php', array('modid' => $module->id, 'userid' => $USER->id))
588        );
589        if (!empty($user) && ($CFG->bloglevel >= BLOG_SITE_LEVEL)) {
590            // View the given users entries about this module.
591            $a = new stdClass;
592            $a->mod = $modulename;
593            $a->user = fullname($user);
594            $options['moduleviewuser'] = array(
595                'string' => get_string('blogentriesbyuseraboutmodule', 'blog', $a),
596                'link' => new moodle_url('/blog/index.php', array('modid' => $module->id, 'userid' => $user->id))
597            );
598        }
599    }
600
601    if (has_capability('moodle/blog:create', $sitecontext)) {
602        // The user can blog about this module.
603        $options['moduleadd'] = array(
604            'string' => get_string('blogaboutthismodule', 'blog', $modulename),
605            'link' => new moodle_url('/blog/edit.php', array('action' => 'add', 'modid' => $module->id))
606        );
607    }
608    // Cache the options.
609    $moduleoptions[$key] = $options;
610    // Return the options.
611    return $options;
612}
613
614/**
615 * This function encapsulates all the logic behind the complex
616 * navigation, titles and headings of the blog listing page, depending
617 * on URL params. It looks at URL params and at the current context level.
618 * It builds and returns an array containing:
619 *
620 * 1. heading: The heading displayed above the blog entries
621 * 2. stradd:  The text to be used as the "Add entry" link
622 * 3. strview: The text to be used as the "View entries" link
623 * 4. url:     The moodle_url object used as the base for add and view links
624 * 5. filters: An array of parameters used to filter blog listings. Used by index.php and the Recent blogs block
625 *
626 * All other variables are set directly in $PAGE
627 *
628 * It uses the current URL to build these variables.
629 * A number of mutually exclusive use cases are used to structure this function.
630 *
631 * @param  int $courseid   course id the the blog is associated to (can be null).
632 * @param  int $groupid    group id to filter blogs I can see (can be null)
633 * @param  int $userid     blog author id (can be null)
634 * @param  int $tagid      tag id to filter (can be null)
635 * @param  string $tag     tag name to filter (can be null)
636 * @param  int $modid      module id the blog is associated to (can be null).
637 * @param  int $entryid    blog entry id to filter(can be null)
638 * @param  string $search  string to search (can be null)
639 * @return array
640 */
641function blog_get_headers($courseid=null, $groupid=null, $userid=null, $tagid=null, $tag=null, $modid=null, $entryid=null,
642        $search = null) {
643    global $CFG, $PAGE, $DB, $USER;
644
645    $id       = optional_param('id', null, PARAM_INT);
646    $tag      = optional_param('tag', $tag, PARAM_NOTAGS);
647    $tagid    = optional_param('tagid', $tagid, PARAM_INT);
648    $userid   = optional_param('userid', $userid, PARAM_INT);
649    $modid    = optional_param('modid', $modid, PARAM_INT);
650    $entryid  = optional_param('entryid', $entryid, PARAM_INT);
651    $groupid  = optional_param('groupid', $groupid, PARAM_INT);
652    $courseid = optional_param('courseid', $courseid, PARAM_INT);
653    $search   = optional_param('search', $search, PARAM_RAW);
654    $action   = optional_param('action', null, PARAM_ALPHA);
655    $confirm  = optional_param('confirm', false, PARAM_BOOL);
656
657    // Ignore userid when action == add.
658    if ($action == 'add' && $userid) {
659        unset($userid);
660        $PAGE->url->remove_params(array('userid'));
661    } else if ($action == 'add' && $entryid) {
662        unset($entryid);
663        $PAGE->url->remove_params(array('entryid'));
664    }
665
666    $headers = array('title' => '', 'heading' => '', 'cm' => null, 'filters' => array());
667
668    $blogurl = new moodle_url('/blog/index.php');
669
670    $headers['stradd'] = get_string('addnewentry', 'blog');
671    $headers['strview'] = null;
672
673    $site = $DB->get_record('course', array('id' => SITEID));
674    $sitecontext = context_system::instance();
675    // Common Lang strings.
676    $strparticipants = get_string("participants");
677    $strblogentries  = get_string("blogentries", 'blog');
678
679    // Prepare record objects as needed.
680    if (!empty($courseid)) {
681        $headers['filters']['course'] = $courseid;
682        $course = $DB->get_record('course', array('id' => $courseid));
683    }
684
685    if (!empty($userid)) {
686        $headers['filters']['user'] = $userid;
687        $user = $DB->get_record('user', array('id' => $userid));
688    }
689
690    if (!empty($groupid)) { // The groupid always overrides courseid.
691        $headers['filters']['group'] = $groupid;
692        $group = $DB->get_record('groups', array('id' => $groupid));
693        $course = $DB->get_record('course', array('id' => $group->courseid));
694    }
695
696    $PAGE->set_pagelayout('standard');
697
698    // The modid always overrides courseid, so the $course object may be reset here.
699    if (!empty($modid) && $CFG->useblogassociations) {
700
701        $headers['filters']['module'] = $modid;
702        // A groupid param may conflict with this coursemod's courseid. Ignore groupid in that case.
703        $courseid = $DB->get_field('course_modules', 'course', array('id' => $modid));
704        $course = $DB->get_record('course', array('id' => $courseid));
705        $cm = $DB->get_record('course_modules', array('id' => $modid));
706        $cm->modname = $DB->get_field('modules', 'name', array('id' => $cm->module));
707        $cm->name = $DB->get_field($cm->modname, 'name', array('id' => $cm->instance));
708        $a = new stdClass();
709        $a->type = get_string('modulename', $cm->modname);
710        $PAGE->set_cm($cm, $course);
711        $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
712        $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
713    }
714
715    // Case 1: No entry, mod, course or user params: all site entries to be shown (filtered by search and tag/tagid)
716    // Note: if action is set to 'add' or 'edit', we do this at the end.
717    if (empty($entryid) && empty($modid) && empty($courseid) && empty($userid) && !in_array($action, array('edit', 'add'))) {
718        $PAGE->navbar->add($strblogentries, $blogurl);
719        $PAGE->set_title($site->fullname);
720        $PAGE->set_heading($site->fullname);
721        $headers['heading'] = get_string('siteblogheading', 'blog');
722    }
723
724    // Case 2: only entryid is requested, ignore all other filters. courseid is used to give more contextual information.
725    if (!empty($entryid)) {
726        $headers['filters']['entry'] = $entryid;
727        $sql = 'SELECT u.* FROM {user} u, {post} p WHERE p.id = ? AND p.userid = u.id';
728        $user = $DB->get_record_sql($sql, array($entryid));
729        $entry = $DB->get_record('post', array('id' => $entryid));
730
731        $blogurl->param('userid', $user->id);
732
733        if (!empty($course)) {
734            $mycourseid = $course->id;
735            $blogurl->param('courseid', $mycourseid);
736        } else {
737            $mycourseid = $site->id;
738        }
739        $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
740
741        $PAGE->navbar->add($strblogentries, $blogurl);
742
743        $blogurl->remove_params('userid');
744        $PAGE->navbar->add($entry->subject, $blogurl);
745        $PAGE->set_title("$shortname: " . fullname($user) . ": $entry->subject");
746        $PAGE->set_heading("$shortname: " . fullname($user) . ": $entry->subject");
747        $headers['heading'] = get_string('blogentrybyuser', 'blog', fullname($user));
748
749        // We ignore tag and search params.
750        if (empty($action) || !$CFG->useblogassociations) {
751            $headers['url'] = $blogurl;
752            return $headers;
753        }
754    }
755
756    if (!empty($userid) && empty($entryid) && ((empty($courseid) && empty($modid)) || !$CFG->useblogassociations)) {
757        // Case 3: A user's blog entries.
758
759        $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
760        $blogurl->param('userid', $userid);
761        $PAGE->set_title("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
762        $PAGE->set_heading("$shortname: " . fullname($user) . ": " . get_string('blog', 'blog'));
763        $headers['heading'] = get_string('userblog', 'blog', fullname($user));
764        $headers['strview'] = get_string('viewuserentries', 'blog', fullname($user));
765
766    } else if (!$CFG->useblogassociations && empty($userid) && !in_array($action, array('edit', 'add'))) {
767        // Case 4: No blog associations, no userid.
768
769        $PAGE->set_title($site->fullname);
770        $PAGE->set_heading($site->fullname);
771        $headers['heading'] = get_string('siteblogheading', 'blog');
772    } else if (!empty($userid) && !empty($modid) && empty($entryid)) {
773        // Case 5: Blog entries associated with an activity by a specific user (courseid ignored).
774
775        $shortname = format_string($site->shortname, true, array('context' => context_course::instance(SITEID)));
776        $blogurl->param('userid', $userid);
777        $blogurl->param('modid', $modid);
778
779        // Course module navigation is handled by build_navigation as the second param.
780        $headers['cm'] = $cm;
781        $PAGE->navbar->add(fullname($user), "$CFG->wwwroot/user/view.php?id=$user->id");
782        $PAGE->navbar->add($strblogentries, $blogurl);
783
784        $PAGE->set_title("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
785        $PAGE->set_heading("$shortname: $cm->name: " . fullname($user) . ': ' . get_string('blogentries', 'blog'));
786
787        $a = new stdClass();
788        $a->user = fullname($user);
789        $a->mod = $cm->name;
790        $a->type = get_string('modulename', $cm->modname);
791        $headers['heading'] = get_string('blogentriesbyuseraboutmodule', 'blog', $a);
792        $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
793        $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
794    } else if (!empty($userid) && !empty($courseid) && empty($modid) && empty($entryid)) {
795        // Case 6: Blog entries associated with a course by a specific user.
796
797        $blogurl->param('userid', $userid);
798        $blogurl->param('courseid', $courseid);
799
800        $PAGE->set_title($course->fullname);
801        $PAGE->set_heading($course->fullname);
802
803        $a = new stdClass();
804        $a->user = fullname($user);
805        $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
806        $a->type = get_string('course');
807        $headers['heading'] = get_string('blogentriesbyuseraboutcourse', 'blog', $a);
808        $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
809        $headers['strview'] = get_string('viewblogentries', 'blog', $a);
810
811        // Remove the userid from the URL to inform the blog_menu block correctly.
812        $blogurl->remove_params(array('userid'));
813    } else if (!empty($groupid) && empty($modid) && empty($entryid)) {
814        // Case 7: Blog entries by members of a group, associated with that group's course.
815
816        $blogurl->param('courseid', $course->id);
817
818        $PAGE->navbar->add($strblogentries, $blogurl);
819        $blogurl->remove_params(array('courseid'));
820        $blogurl->param('groupid', $groupid);
821        $PAGE->navbar->add($group->name, $blogurl);
822
823        $PAGE->set_title($course->fullname);
824        $PAGE->set_heading($course->fullname);
825
826        $a = new stdClass();
827        $a->group = $group->name;
828        $a->course = format_string($course->fullname, true, array('context' => context_course::instance($course->id)));
829        $a->type = get_string('course');
830        $headers['heading'] = get_string('blogentriesbygroupaboutcourse', 'blog', $a);
831        $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
832        $headers['strview'] = get_string('viewblogentries', 'blog', $a);
833    } else if (!empty($groupid) && !empty($modid) && empty($entryid)) {
834        // Case 8: Blog entries by members of a group, associated with an activity in that course.
835
836        $headers['cm'] = $cm;
837        $blogurl->param('modid', $modid);
838        $PAGE->navbar->add($strblogentries, $blogurl);
839
840        $blogurl->param('groupid', $groupid);
841        $PAGE->navbar->add($group->name, $blogurl);
842
843        $PAGE->set_title($course->fullname);
844        $PAGE->set_heading($course->fullname);
845
846        $a = new stdClass();
847        $a->group = $group->name;
848        $a->mod = $cm->name;
849        $a->type = get_string('modulename', $cm->modname);
850        $headers['heading'] = get_string('blogentriesbygroupaboutmodule', 'blog', $a);
851        $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
852        $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
853
854    } else if (!empty($modid) && empty($userid) && empty($groupid) && empty($entryid)) {
855        // Case 9: All blog entries associated with an activity.
856
857        $PAGE->set_cm($cm, $course);
858        $blogurl->param('modid', $modid);
859        $PAGE->navbar->add($strblogentries, $blogurl);
860        $PAGE->set_title($course->fullname);
861        $PAGE->set_heading($course->fullname);
862        $headers['heading'] = get_string('blogentriesabout', 'blog', $cm->name);
863        $a = new stdClass();
864        $a->type = get_string('modulename', $cm->modname);
865        $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
866        $headers['strview'] = get_string('viewallmodentries', 'blog', $a);
867    } else if (!empty($courseid) && empty($userid) && empty($groupid) && empty($modid) && empty($entryid)) {
868        // Case 10: All blog entries associated with a course.
869
870        $blogurl->param('courseid', $courseid);
871        $PAGE->navbar->add($strblogentries, $blogurl);
872        $PAGE->set_title($course->fullname);
873        $PAGE->set_heading($course->fullname);
874        $a = new stdClass();
875        $a->type = get_string('course');
876        $headers['heading'] = get_string('blogentriesabout',
877                                         'blog',
878                                         format_string($course->fullname,
879                                                       true,
880                                                       array('context' => context_course::instance($course->id))));
881        $headers['stradd'] = get_string('blogaboutthis', 'blog', $a);
882        $headers['strview'] = get_string('viewblogentries', 'blog', $a);
883        $blogurl->remove_params(array('userid'));
884    }
885
886    if (!in_array($action, array('edit', 'add'))) {
887        // Append Tag info.
888        if (!empty($tagid)) {
889            $headers['filters']['tag'] = $tagid;
890            $blogurl->param('tagid', $tagid);
891            $tagrec = $DB->get_record('tag', array('id' => $tagid));
892            $PAGE->navbar->add($tagrec->name, $blogurl);
893        } else if (!empty($tag)) {
894            if ($tagrec = $DB->get_record('tag', array('name' => $tag))) {
895                $tagid = $tagrec->id;
896                $headers['filters']['tag'] = $tagid;
897                $blogurl->param('tag', $tag);
898                $PAGE->navbar->add(get_string('tagparam', 'blog', $tag), $blogurl);
899            }
900        }
901
902        // Append Search info.
903        if (!empty($search) && has_capability('moodle/blog:search', $sitecontext)) {
904            $headers['filters']['search'] = $search;
905            $blogurl->param('search', $search);
906            $PAGE->navbar->add(get_string('searchterm', 'blog', $search), $blogurl->out());
907        }
908    }
909
910    // Append edit mode info.
911    if (!empty($action) && $action == 'add') {
912
913    } else if (!empty($action) && $action == 'edit') {
914        $PAGE->navbar->add(get_string('editentry', 'blog'));
915    }
916
917    if (empty($headers['url'])) {
918        $headers['url'] = $blogurl;
919    }
920    return $headers;
921}
922
923/**
924 * Shortcut function for getting a count of blog entries associated with a course or a module
925 * @param int $courseid The ID of the course
926 * @param int $cmid The ID of the course_modules
927 * @return string The number of associated entries
928 */
929function blog_get_associated_count($courseid, $cmid=null) {
930    global $DB;
931    $context = context_course::instance($courseid);
932    if ($cmid) {
933        $context = context_module::instance($cmid);
934    }
935    return $DB->count_records('blog_association', array('contextid' => $context->id));
936}
937
938/**
939 * Running addtional permission check on plugin, for example, plugins
940 * may have switch to turn on/off comments option, this callback will
941 * affect UI display, not like pluginname_comment_validate only throw
942 * exceptions.
943 * blog_comment_validate will be called before viewing/adding/deleting
944 * comment, so don't repeat checks.
945 * Capability check has been done in comment->check_permissions(), we
946 * don't need to do it again here.
947 *
948 * @package  core_blog
949 * @category comment
950 *
951 * @param stdClass $commentparam {
952 *              context  => context the context object
953 *              courseid => int course id
954 *              cm       => stdClass course module object
955 *              commentarea => string comment area
956 *              itemid      => int itemid
957 * }
958 * @return array
959 */
960function blog_comment_permissions($commentparam) {
961    global $DB;
962
963    // If blog is public and current user is guest, then don't let him post comments.
964    $blogentry = $DB->get_record('post', array('id' => $commentparam->itemid), 'publishstate', MUST_EXIST);
965
966    if ($blogentry->publishstate != 'public') {
967        if (!isloggedin() || isguestuser()) {
968            return array('post' => false, 'view' => true);
969        }
970    }
971    return array('post' => true, 'view' => true);
972}
973
974/**
975 * Validate comment parameter before perform other comments actions
976 *
977 * @package  core_blog
978 * @category comment
979 *
980 * @param stdClass $comment {
981 *              context  => context the context object
982 *              courseid => int course id
983 *              cm       => stdClass course module object
984 *              commentarea => string comment area
985 *              itemid      => int itemid
986 * }
987 * @return boolean
988 */
989function blog_comment_validate($commentparam) {
990    global $CFG, $DB, $USER;
991
992    // Check if blogs are enabled user can comment.
993    if (empty($CFG->enableblogs) || empty($CFG->blogusecomments)) {
994        throw new comment_exception('nopermissiontocomment');
995    }
996
997    // Validate comment area.
998    if ($commentparam->commentarea != 'format_blog') {
999        throw new comment_exception('invalidcommentarea');
1000    }
1001
1002    $blogentry = $DB->get_record('post', array('id' => $commentparam->itemid), '*', MUST_EXIST);
1003
1004    // Validation for comment deletion.
1005    if (!empty($commentparam->commentid)) {
1006        if ($record = $DB->get_record('comments', array('id' => $commentparam->commentid))) {
1007            if ($record->commentarea != 'format_blog') {
1008                throw new comment_exception('invalidcommentarea');
1009            }
1010            if ($record->contextid != $commentparam->context->id) {
1011                throw new comment_exception('invalidcontext');
1012            }
1013            if ($record->itemid != $commentparam->itemid) {
1014                throw new comment_exception('invalidcommentitemid');
1015            }
1016        } else {
1017            throw new comment_exception('invalidcommentid');
1018        }
1019    }
1020
1021    // Validate if user has blog view permission.
1022    $sitecontext = context_system::instance();
1023    return has_capability('moodle/blog:view', $sitecontext) &&
1024            blog_user_can_view_user_entry($blogentry->userid, $blogentry);
1025}
1026
1027/**
1028 * Return a list of page types
1029 * @param string $pagetype current page type
1030 * @param stdClass $parentcontext Block's parent context
1031 * @param stdClass $currentcontext Current context of block
1032 */
1033function blog_page_type_list($pagetype, $parentcontext, $currentcontext) {
1034    return array(
1035        '*' => get_string('page-x', 'pagetype'),
1036        'blog-*' => get_string('page-blog-x', 'blog'),
1037        'blog-index' => get_string('page-blog-index', 'blog'),
1038        'blog-edit' => get_string('page-blog-edit', 'blog')
1039    );
1040}
1041
1042/**
1043 * Add nodes to myprofile page.
1044 *
1045 * @param \core_user\output\myprofile\tree $tree Tree object
1046 * @param stdClass $user user object
1047 * @param bool $iscurrentuser
1048 * @param stdClass $course Course object
1049 *
1050 * @return bool
1051 */
1052function core_blog_myprofile_navigation(core_user\output\myprofile\tree $tree, $user, $iscurrentuser, $course) {
1053    global $CFG;
1054    if (!blog_is_enabled_for_user() || isguestuser($user)) {
1055        // The guest user cannot post, so it is not possible to view any posts.
1056        // Also blogs might be disabled.
1057        // May as well just bail aggressively here.
1058        return true;
1059    }
1060    if (!blog_user_can_view_user_entry($user->id)) {
1061        return true;
1062    }
1063    $url = new moodle_url("/blog/index.php", array('userid' => $user->id));
1064    if (!empty($course)) {
1065        $url->param('courseid', $course->id);
1066    }
1067    if ($iscurrentuser) {
1068        $title = get_string('blogentries', 'core_blog');
1069    } else {
1070        $title = get_string('myprofileuserblogs', 'core_blog');
1071    }
1072    $blognode = new core_user\output\myprofile\node('miscellaneous', 'blogs', $title, null, $url);
1073    $tree->add_node($blognode);
1074    return true;
1075}
1076
1077/**
1078 * Returns posts tagged with a specified tag.
1079 *
1080 * @param core_tag_tag $tag
1081 * @param bool $exclusivemode if set to true it means that no other entities tagged with this tag
1082 *             are displayed on the page and the per-page limit may be bigger
1083 * @param int $fromctx context id where the link was displayed, may be used by callbacks
1084 *            to display items in the same context first
1085 * @param int $ctx context id where to search for records
1086 * @param bool $rec search in subcontexts as well
1087 * @param int $page 0-based number of page being displayed
1088 * @return \core_tag\output\tagindex
1089 */
1090function blog_get_tagged_posts($tag, $exclusivemode = false, $fromctx = 0, $ctx = 0, $rec = true, $page = 0) {
1091    global $CFG, $OUTPUT;
1092    require_once($CFG->dirroot.'/user/lib.php');
1093
1094    $systemcontext = context_system::instance();
1095    $perpage = $exclusivemode ? 20 : 5;
1096    $context = $ctx ? context::instance_by_id($ctx) : context_system::instance();
1097
1098    $content = '';
1099    if (empty($CFG->enableblogs) || !has_capability('moodle/blog:view', $systemcontext)) {
1100        // Blogs are not enabled or are not visible to the current user.
1101        $totalpages = 0;
1102    } else if ($context->contextlevel != CONTEXT_SYSTEM && empty($CFG->useblogassociations)) {
1103        // No blog entries can be associated to the non-system context.
1104        $totalpages = 0;
1105    } else if (!$rec && $context->contextlevel != CONTEXT_COURSE && $context->contextlevel != CONTEXT_MODULE) {
1106        // No blog entries can be associated with category or block context.
1107        $totalpages = 0;
1108    } else {
1109        require_once($CFG->dirroot.'/blog/locallib.php');
1110
1111        $filters = array('tag' => $tag->id);
1112        if ($rec) {
1113            if ($context->contextlevel != CONTEXT_SYSTEM) {
1114                $filters['context'] = $context->id;
1115            }
1116        } else if ($context->contextlevel == CONTEXT_COURSE) {
1117            $filters['course'] = $context->instanceid;
1118        } else if ($context->contextlevel == CONTEXT_MODULE) {
1119            $filters['module'] = $context->instanceid;
1120        }
1121        $bloglisting = new blog_listing($filters);
1122        $blogs = $bloglisting->get_entries($page * $perpage, $perpage);
1123        $totalcount = $bloglisting->count_entries();
1124        $totalpages = ceil($totalcount / $perpage);
1125        if (!empty($blogs)) {
1126            $tagfeed = new core_tag\output\tagfeed();
1127            foreach ($blogs as $blog) {
1128                $user = fullclone($blog);
1129                $user->id = $blog->userid;
1130                $user->deleted = 0;
1131                $img = $OUTPUT->user_picture($user, array('size' => 35));
1132                $subject = format_string($blog->subject);
1133
1134                if ($blog->publishstate == 'draft') {
1135                    $class = 'dimmed';
1136                } else {
1137                    $class = '';
1138                }
1139
1140                $url = new moodle_url('/blog/index.php', array('entryid' => $blog->id));
1141                $subject = html_writer::link($url, $subject, array('class' => $class));
1142
1143                $fullname = fullname($user);
1144                if (user_can_view_profile($user)) {
1145                    $profilelink = new moodle_url('/user/view.php', array('id' => $blog->userid));
1146                    $fullname = html_writer::link($profilelink, $fullname);
1147                }
1148                $details = $fullname . ', ' . userdate($blog->created);
1149
1150                $tagfeed->add($img, $subject, $details);
1151            }
1152
1153            $items = $tagfeed->export_for_template($OUTPUT);
1154            $content = $OUTPUT->render_from_template('core_tag/tagfeed', $items);
1155
1156            $urlparams = array('tagid' => $tag->id);
1157            if ($context->contextlevel == CONTEXT_COURSE) {
1158                $urlparams['courseid'] = $context->instanceid;
1159            } else if ($context->contextlevel == CONTEXT_MODULE) {
1160                $urlparams['modid'] = $context->instanceid;
1161            }
1162            $allblogsurl = new moodle_url('/blog/index.php', $urlparams);
1163
1164            $rv = new core_tag\output\tagindex($tag, 'core', 'post',
1165                    $content,
1166                    $exclusivemode, $fromctx, $ctx, $rec, $page, $totalpages);
1167            $rv->exclusiveurl = $allblogsurl;
1168            return $rv;
1169        }
1170    }
1171
1172    $rv = new core_tag\output\tagindex($tag, 'core', 'post',
1173            $content,
1174            $exclusivemode, $fromctx, $ctx, $rec, $page, $totalpages);
1175    $rv->exclusiveurl = null;
1176    return $rv;
1177}
1178
1179/**
1180 * Validate the access to a blog.
1181 *
1182 * @param  int $courseid course id the the blog is associated to (can be null).
1183 * @param  int $modid    module id the blog is associated to (can be null).
1184 * @param  int $groupid  group id to filter blogs I can see (can be null)
1185 * @param  int $entryid  blog entry id (can be null)
1186 * @param  int $userid   blog author id (can be null)
1187 * @return array with the calculated course and id
1188 * @since  Moodle 3.6
1189 */
1190function blog_validate_access($courseid, $modid, $groupid, $entryid, $userid) {
1191    global $CFG, $DB, $USER, $COURSE;
1192
1193    $sitecontext = context_system::instance();
1194
1195    // Add courseid if modid or groupid is specified: This is used for navigation and title.
1196    if (!empty($modid) && empty($courseid)) {
1197        $courseid = $DB->get_field('course_modules', 'course', array('id' => $modid));
1198    }
1199
1200    if (!empty($groupid) && empty($courseid)) {
1201        $courseid = $DB->get_field('groups', 'courseid', array('id' => $groupid));
1202    }
1203
1204    if (!$userid && has_capability('moodle/blog:view', $sitecontext) && $CFG->bloglevel > BLOG_USER_LEVEL) {
1205        if ($entryid) {
1206            if (!$entryobject = $DB->get_record('post', array('id' => $entryid))) {
1207                print_error('nosuchentry', 'blog');
1208            }
1209            $userid = $entryobject->userid;
1210        }
1211    } else if (!$userid) {
1212        $userid = $USER->id;
1213    }
1214
1215    if (!empty($modid)) {
1216        if ($CFG->bloglevel < BLOG_SITE_LEVEL) {
1217            print_error(get_string('nocourseblogs', 'blog'));
1218        }
1219        if (!$mod = $DB->get_record('course_modules', array('id' => $modid))) {
1220            print_error(get_string('invalidmodid', 'blog'));
1221        }
1222        $courseid = $mod->course;
1223    }
1224
1225    if ((empty($courseid) ? true : $courseid == SITEID) && empty($userid)) {
1226        if ($CFG->bloglevel < BLOG_SITE_LEVEL) {
1227            print_error('siteblogdisable', 'blog');
1228        }
1229        if (!has_capability('moodle/blog:view', $sitecontext)) {
1230            print_error('cannotviewsiteblog', 'blog');
1231        }
1232
1233        $COURSE = $DB->get_record('course', array('format' => 'site'));
1234        $courseid = $COURSE->id;
1235    }
1236
1237    if (!empty($courseid)) {
1238        if (!$course = $DB->get_record('course', array('id' => $courseid))) {
1239            print_error('invalidcourseid');
1240        }
1241
1242        $courseid = $course->id;
1243
1244        if (!has_capability('moodle/blog:view', $sitecontext)) {
1245            print_error('cannotviewcourseblog', 'blog');
1246        }
1247    } else {
1248        $coursecontext = context_course::instance(SITEID);
1249    }
1250
1251    if (!empty($groupid)) {
1252        if ($CFG->bloglevel < BLOG_SITE_LEVEL) {
1253            print_error('groupblogdisable', 'blog');
1254        }
1255
1256        if (! $group = groups_get_group($groupid)) {
1257            print_error(get_string('invalidgroupid', 'blog'));
1258        }
1259
1260        if (!$course = $DB->get_record('course', array('id' => $group->courseid))) {
1261            print_error('invalidcourseid');
1262        }
1263
1264        $coursecontext = context_course::instance($course->id);
1265        $courseid = $course->id;
1266
1267        if (!has_capability('moodle/blog:view', $sitecontext)) {
1268            print_error(get_string('cannotviewcourseorgroupblog', 'blog'));
1269        }
1270
1271        if (groups_get_course_groupmode($course) == SEPARATEGROUPS &&
1272                !has_capability('moodle/site:accessallgroups', $coursecontext)) {
1273
1274            if (!groups_is_member($groupid)) {
1275                print_error('notmemberofgroup');
1276            }
1277        }
1278    }
1279
1280    if (!empty($userid)) {
1281        if ($CFG->bloglevel < BLOG_USER_LEVEL) {
1282            print_error('blogdisable', 'blog');
1283        }
1284
1285        if (!$user = $DB->get_record('user', array('id' => $userid))) {
1286            print_error('invaliduserid');
1287        }
1288
1289        if ($user->deleted) {
1290            print_error('userdeleted');
1291        }
1292
1293        if ($USER->id == $userid) {
1294            if (!has_capability('moodle/blog:create', $sitecontext)
1295              && !has_capability('moodle/blog:view', $sitecontext)) {
1296                print_error('donothaveblog', 'blog');
1297            }
1298        } else {
1299            if (!has_capability('moodle/blog:view', $sitecontext) || !blog_user_can_view_user_entry($userid)) {
1300                print_error('cannotviewcourseblog', 'blog');
1301            }
1302        }
1303    }
1304    return array($courseid, $userid);
1305}
1306