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[friendica.git] / src / Protocol / ActivityPub / Processor.php
1 <?php
2 /**
3  * @copyright Copyright (C) 2010-2022, the Friendica project
4  *
5  * @license GNU AGPL version 3 or any later version
6  *
7  * This program is free software: you can redistribute it and/or modify
8  * it under the terms of the GNU Affero General Public License as
9  * published by the Free Software Foundation, either version 3 of the
10  * License, or (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU Affero General Public License for more details.
16  *
17  * You should have received a copy of the GNU Affero General Public License
18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
19  *
20  */
21
22 namespace Friendica\Protocol\ActivityPub;
23
24 use Friendica\Content\Text\BBCode;
25 use Friendica\Content\Text\HTML;
26 use Friendica\Content\Text\Markdown;
27 use Friendica\Core\Logger;
28 use Friendica\Core\Protocol;
29 use Friendica\Core\System;
30 use Friendica\Database\DBA;
31 use Friendica\DI;
32 use Friendica\Model\APContact;
33 use Friendica\Model\Contact;
34 use Friendica\Model\Conversation;
35 use Friendica\Model\Event;
36 use Friendica\Model\GServer;
37 use Friendica\Model\Item;
38 use Friendica\Model\ItemURI;
39 use Friendica\Model\Mail;
40 use Friendica\Model\Tag;
41 use Friendica\Model\User;
42 use Friendica\Model\Post;
43 use Friendica\Protocol\Activity;
44 use Friendica\Protocol\ActivityPub;
45 use Friendica\Protocol\Relay;
46 use Friendica\Util\DateTimeFormat;
47 use Friendica\Util\JsonLD;
48 use Friendica\Util\Strings;
49
50 /**
51  * ActivityPub Processor Protocol class
52  */
53 class Processor
54 {
55         /**
56          * Extracts the tag character (#, @, !) from mention links
57          *
58          * @param string $body
59          * @return string
60          */
61         protected static function normalizeMentionLinks(string $body): string
62         {
63                 return preg_replace('%\[url=([^\[\]]*)]([#@!])(.*?)\[/url]%ism', '$2[url=$1]$3[/url]', $body);
64         }
65
66         /**
67          * Convert the language array into a language JSON
68          *
69          * @param array $languages
70          * @return string language JSON
71          */
72         private static function processLanguages(array $languages)
73         {
74                 $codes = array_keys($languages);
75                 $lang = [];
76                 foreach ($codes as $code) {
77                         $lang[$code] = 1;
78                 }
79
80                 if (empty($lang)) {
81                         return '';
82                 }
83
84                 return json_encode($lang);
85         }
86         /**
87          * Replaces emojis in the body
88          *
89          * @param array $emojis
90          * @param string $body
91          *
92          * @return string with replaced emojis
93          */
94         private static function replaceEmojis(int $uri_id, $body, array $emojis)
95         {
96                 $body = strtr($body,
97                         array_combine(
98                                 array_column($emojis, 'name'),
99                                 array_map(function ($emoji) {
100                                         return '[emoji=' . $emoji['href'] . ']' . $emoji['name'] . '[/emoji]';
101                                 }, $emojis)
102                         )
103                 );
104
105                 // We store the emoji here to be able to avoid storing it in the media
106                 foreach ($emojis as $emoji) {
107                         Post\Link::getByLink($uri_id, $emoji['href']);
108                 }
109                 return $body;
110         }
111
112         /**
113          * Store attached media files in the post-media table
114          *
115          * @param int $uriid
116          * @param array $attachment
117          * @return void
118          */
119         private static function storeAttachmentAsMedia(int $uriid, array $attachment)
120         {
121                 if (empty($attachment['url'])) {
122                         return;
123                 }
124
125                 $data = ['uri-id' => $uriid];
126                 $data['type'] = Post\Media::UNKNOWN;
127                 $data['url'] = $attachment['url'];
128                 $data['mimetype'] = $attachment['mediaType'] ?? null;
129                 $data['height'] = $attachment['height'] ?? null;
130                 $data['width'] = $attachment['width'] ?? null;
131                 $data['size'] = $attachment['size'] ?? null;
132                 $data['preview'] = $attachment['image'] ?? null;
133                 $data['description'] = $attachment['name'] ?? null;
134
135                 Post\Media::insert($data);
136         }
137
138         /**
139          * Stire attachment data
140          *
141          * @param array   $activity
142          * @param array   $item
143          */
144         private static function storeAttachments($activity, $item)
145         {
146                 if (empty($activity['attachments'])) {
147                         return;
148                 }
149
150                 foreach ($activity['attachments'] as $attach) {
151                         self::storeAttachmentAsMedia($item['uri-id'], $attach);
152                 }
153         }
154
155         /**
156          * Updates a message
157          *
158          * @param array $activity Activity array
159          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
160          */
161         public static function updateItem($activity)
162         {
163                 $item = Post::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity', 'post-type'], ['uri' => $activity['id']]);
164                 if (!DBA::isResult($item)) {
165                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
166                         $item = self::createItem($activity);
167                         if (empty($item)) {
168                                 return;
169                         }
170
171                         self::postItem($activity, $item);
172                         return;
173                 }
174
175                 $item['changed'] = DateTimeFormat::utcNow();
176                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
177
178                 $item = self::processContent($activity, $item);
179
180                 self::storeAttachments($activity, $item);
181
182                 if (empty($item)) {
183                         return;
184                 }
185
186                 Item::update($item, ['uri' => $activity['id']]);
187
188                 if ($activity['object_type'] == 'as:Event') {
189                         $posts = Post::select(['event-id', 'uid'], ["`uri` = ? AND `event-id` > ?", $activity['id'], 0]);
190                         while ($post = DBA::fetch($posts)) {
191                                 self::updateEvent($post['event-id'], $activity);
192                         }
193                 }
194         }
195
196         /**
197          * Update an existing event
198          *
199          * @param int $event_id
200          * @param array $activity
201          */
202         private static function updateEvent(int $event_id, array $activity)
203         {
204                 $event = DBA::selectFirst('event', [], ['id' => $event_id]);
205
206                 $event['edited']   = DateTimeFormat::utc($activity['updated']);
207                 $event['summary']  = HTML::toBBCode($activity['name']);
208                 $event['desc']     = HTML::toBBCode($activity['content']);
209                 $event['start']    = $activity['start-time'];
210                 $event['finish']   = $activity['end-time'];
211                 $event['nofinish'] = empty($event['finish']);
212                 $event['location'] = $activity['location'];
213
214                 Logger::info('Updating event', ['uri' => $activity['id'], 'id' => $event_id]);
215                 Event::store($event);
216         }
217
218         /**
219          * Prepares data for a message
220          *
221          * @param array $activity Activity array
222          * @return array Internal item
223          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
224          * @throws \ImagickException
225          */
226         public static function createItem($activity)
227         {
228                 $item = [];
229                 $item['verb'] = Activity::POST;
230                 $item['thr-parent'] = $activity['reply-to-id'];
231
232                 if ($activity['reply-to-id'] == $activity['id']) {
233                         $item['gravity'] = GRAVITY_PARENT;
234                         $item['object-type'] = Activity\ObjectType::NOTE;
235                 } else {
236                         $item['gravity'] = GRAVITY_COMMENT;
237                         $item['object-type'] = Activity\ObjectType::COMMENT;
238                 }
239
240                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
241                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id']]);
242                         self::fetchMissingActivity($activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
243                 }
244
245                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
246
247                 /// @todo What to do with $activity['context']?
248                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Post::exists(['uri' => $item['thr-parent']])) {
249                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
250                         return [];
251                 }
252
253                 $item['network'] = Protocol::ACTIVITYPUB;
254                 $item['author-link'] = $activity['author'];
255                 $item['author-id'] = Contact::getIdForURL($activity['author']);
256                 $item['owner-link'] = $activity['actor'];
257                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
258
259                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
260                         $item['private'] = Item::UNLISTED;
261                 } elseif (in_array(0, $activity['receiver'])) {
262                         $item['private'] = Item::PUBLIC;
263                 } else {
264                         $item['private'] = Item::PRIVATE;
265                 }
266
267                 if (!empty($activity['raw'])) {
268                         $item['source'] = $activity['raw'];
269                         $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
270                         $item['conversation-href'] = $activity['context'] ?? '';
271                         $item['conversation-uri'] = $activity['conversation'] ?? '';
272
273                         if (isset($activity['push'])) {
274                                 $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
275                         }
276                 }
277
278                 if (!empty($activity['from-relay'])) {
279                         $item['direction'] = Conversation::RELAY;
280                 }
281
282                 if ($activity['object_type'] == 'as:Article') {
283                         $item['post-type'] = Item::PT_ARTICLE;
284                 } elseif ($activity['object_type'] == 'as:Audio') {
285                         $item['post-type'] = Item::PT_AUDIO;
286                 } elseif ($activity['object_type'] == 'as:Document') {
287                         $item['post-type'] = Item::PT_DOCUMENT;
288                 } elseif ($activity['object_type'] == 'as:Event') {
289                         $item['post-type'] = Item::PT_EVENT;
290                 } elseif ($activity['object_type'] == 'as:Image') {
291                         $item['post-type'] = Item::PT_IMAGE;
292                 } elseif ($activity['object_type'] == 'as:Page') {
293                         $item['post-type'] = Item::PT_PAGE;
294                 } elseif ($activity['object_type'] == 'as:Question') {
295                         $item['post-type'] = Item::PT_POLL;
296                 } elseif ($activity['object_type'] == 'as:Video') {
297                         $item['post-type'] = Item::PT_VIDEO;
298                 } else {
299                         $item['post-type'] = Item::PT_NOTE;
300                 }
301
302                 $item['isForum'] = false;
303
304                 if (!empty($activity['thread-completion'])) {
305                         if ($activity['thread-completion'] != $item['owner-id']) {
306                                 $actor = Contact::getById($activity['thread-completion'], ['url']);
307                                 $item['causer-link'] = $actor['url'];
308                                 $item['causer-id'] = $activity['thread-completion'];
309                                 Logger::info('Use inherited actor as causer.', ['id' => $item['owner-id'], 'activity' => $activity['thread-completion'], 'owner' => $item['owner-link'], 'actor' => $actor['url']]);
310                         } else {
311                                 // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
312                                 $item['causer-link'] = $item['owner-link'];
313                                 $item['causer-id']   = $item['owner-id'];
314                                 Logger::info('Use actor as causer.', ['id' => $item['owner-id'], 'actor' => $item['owner-link']]);
315                         }
316
317                         $item['owner-link'] = $item['author-link'];
318                         $item['owner-id'] = $item['author-id'];
319                 } else {
320                         $actor = APContact::getByURL($item['owner-link'], false);
321                         $item['isForum'] = ($actor['type'] == 'Group');
322                 }
323
324                 $item['uri'] = $activity['id'];
325
326                 if (empty($activity['published']) || empty($activity['updated'])) {
327                         DI::logger()->notice('published or updated keys are empty for activity', ['activity' => $activity, 'callstack' => System::callstack(10)]);
328                 }
329
330                 $item['created'] = DateTimeFormat::utc($activity['published'] ?? 'now');
331                 $item['edited'] = DateTimeFormat::utc($activity['updated'] ?? 'now');
332                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
333                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
334
335                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
336                 if (empty($item['uri-id'])) {
337                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
338                         return [];
339                 }
340
341                 $item = self::processContent($activity, $item);
342                 if (empty($item)) {
343                         Logger::info('Message was not processed');
344                         return [];
345                 }
346
347                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
348
349                 self::storeAttachments($activity, $item);
350
351                 // We received the post via AP, so we set the protocol of the server to AP
352                 $contact = Contact::getById($item['author-id'], ['gsid']);
353                 if (!empty($contact['gsid'])) {
354                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
355                 }
356
357                 if ($item['author-id'] != $item['owner-id']) {
358                         $contact = Contact::getById($item['owner-id'], ['gsid']);
359                         if (!empty($contact['gsid'])) {
360                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
361                         }
362                 }
363
364                 return $item;
365         }
366
367         /**
368          * Delete items
369          *
370          * @param array $activity
371          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
372          * @throws \ImagickException
373          */
374         public static function deleteItem($activity)
375         {
376                 $owner = Contact::getIdForURL($activity['actor']);
377
378                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
379                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
380         }
381
382         /**
383          * Prepare the item array for an activity
384          *
385          * @param array $activity Activity array
386          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
387          * @throws \ImagickException
388          */
389         public static function addTag($activity)
390         {
391                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
392                         return;
393                 }
394
395                 foreach ($activity['receiver'] as $receiver) {
396                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
397                         if (!DBA::isResult($item)) {
398                                 // We don't fetch missing content for this purpose
399                                 continue;
400                         }
401
402                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
403                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
404                                 continue;
405                         }
406
407                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
408                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
409                 }
410         }
411
412         /**
413          * Prepare the item array for an activity
414          *
415          * @param array  $activity Activity array
416          * @param string $verb     Activity verb
417          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
418          * @throws \ImagickException
419          */
420         public static function createActivity($activity, $verb)
421         {
422                 $item = self::createItem($activity);
423                 if (empty($item)) {
424                         return;
425                 }
426
427                 $item['verb'] = $verb;
428                 $item['thr-parent'] = $activity['object_id'];
429                 $item['gravity'] = GRAVITY_ACTIVITY;
430                 unset($item['post-type']);
431                 $item['object-type'] = Activity\ObjectType::NOTE;
432
433                 if (!empty($activity['content'])) {
434                         $item['body'] = HTML::toBBCode($activity['content']);
435                 }
436
437                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
438
439                 self::postItem($activity, $item);
440         }
441
442         /**
443          * Fetch the Uri-Id of a post for the "featured" collection
444          *
445          * @param array $activity 
446          * @return null|int 
447          */
448         private static function getUriIdForFeaturedCollection(array $activity)
449         {
450                 $actor = APContact::getByURL($activity['actor']);
451                 if (empty($actor)) {
452                         return null;
453                 }
454
455                 // Refetch the account when the "featured" collection is missing.
456                 // This can be removed in a future version (end of 2022 should be good).
457                 if (empty($actor['featured'])) {
458                         $actor = APContact::getByURL($activity['actor'], true);
459                         if (empty($actor)) {
460                                 return null;
461                         }
462                 }
463
464                 if ($activity['target_id'] != $actor['featured']) {
465                         return null;
466                 }
467
468                 $id = Contact::getIdForURL($activity['actor']);
469                 if (empty($id)) {
470                         return null;
471                 }
472
473                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id'], 'author-id' => $id]);
474                 if (!empty($parent['uri-id'])) {
475                         return $parent['uri-id'];
476                 }
477
478                 return null;
479         }
480
481         /**
482          * Add a post to the "Featured" collection
483          *
484          * @param array $activity 
485          */
486         public static function addToFeaturedCollection(array $activity)
487         {
488                 $uriid = self::getUriIdForFeaturedCollection($activity);
489                 if (empty($uriid)) {
490                         return;
491                 }
492
493                 Logger::debug('Add post to featured collection', ['uri-id' => $uriid]);
494
495                 // @todo Add functionality
496         }
497
498         /**
499          * Remove a post to the "Featured" collection
500          *
501          * @param array $activity 
502          */
503         public static function removeFromFeaturedCollection(array $activity)
504         {
505                 $uriid = self::getUriIdForFeaturedCollection($activity);
506                 if (empty($uriid)) {
507                         return;
508                 }
509
510                 Logger::debug('Remove post from featured collection', ['uri-id' => $uriid]);
511
512                 // @todo Add functionality
513         }
514
515         /**
516          * Create an event
517          *
518          * @param array $activity Activity array
519          * @param array $item
520          *
521          * @return int event id
522          * @throws \Exception
523          */
524         public static function createEvent($activity, $item)
525         {
526                 $event['summary']   = HTML::toBBCode($activity['name'] ?: $activity['summary']);
527                 $event['desc']      = HTML::toBBCode($activity['content']);
528                 $event['start']     = $activity['start-time'];
529                 $event['finish']    = $activity['end-time'];
530                 $event['nofinish']  = empty($event['finish']);
531                 $event['location']  = $activity['location'];
532                 $event['cid']       = $item['contact-id'];
533                 $event['uid']       = $item['uid'];
534                 $event['uri']       = $item['uri'];
535                 $event['edited']    = $item['edited'];
536                 $event['private']   = $item['private'];
537                 $event['guid']      = $item['guid'];
538                 $event['plink']     = $item['plink'];
539                 $event['network']   = $item['network'];
540                 $event['protocol']  = $item['protocol'];
541                 $event['direction'] = $item['direction'];
542                 $event['source']    = $item['source'];
543
544                 $ev = DBA::selectFirst('event', ['id'], ['uri' => $item['uri'], 'uid' => $item['uid']]);
545                 if (DBA::isResult($ev)) {
546                         $event['id'] = $ev['id'];
547                 }
548
549                 $event_id = Event::store($event);
550
551                 Logger::info('Event was stored', ['id' => $event_id]);
552
553                 return $event_id;
554         }
555
556         /**
557          * Process the content
558          *
559          * @param array $activity Activity array
560          * @param array $item
561          * @return array|bool Returns the item array or false if there was an unexpected occurrence
562          * @throws \Exception
563          */
564         private static function processContent($activity, $item)
565         {
566                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
567                         $item['title'] = Markdown::toBBCode($activity['name']);
568                         $content = Markdown::toBBCode($activity['content']);
569                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
570                         $item['title'] = $activity['name'];
571                         $content = $activity['content'];
572                 } else {
573                         // By default assume "text/html"
574                         $item['title'] = HTML::toBBCode($activity['name']);
575                         $content = HTML::toBBCode($activity['content']);
576                 }
577
578                 if (!empty($activity['languages'])) {
579                         $item['language'] = self::processLanguages($activity['languages']);
580                 }
581
582                 if (!empty($activity['emojis'])) {
583                         $content = self::replaceEmojis($item['uri-id'], $content, $activity['emojis']);
584                 }
585
586                 $content = self::addMentionLinks($content, $activity['tags']);
587
588                 if (!empty($activity['source'])) {
589                         $item['body'] = $activity['source'];
590                         $item['raw-body'] = $content;
591                         $item['body'] = Item::improveSharedDataInBody($item);
592                 } else {
593                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
594                                 $item_private = !in_array(0, $activity['item_receiver']);
595                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
596                                 if (!DBA::isResult($parent)) {
597                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
598                                         return false;
599                                 }
600                                 if ($item_private && ($parent['private'] != Item::PRIVATE)) {
601                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
602                                         return false;
603                                 }
604
605                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
606                         }
607                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
608                         $item['raw-body'] = $item['body'] = $content;
609                 }
610
611                 self::storeFromBody($item);
612                 self::storeTags($item['uri-id'], $activity['tags']);
613
614                 self::storeReceivers($item['uri-id'], $activity['receiver_urls'] ?? []);
615
616                 $item['location'] = $activity['location'];
617
618                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
619                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
620                 }
621
622                 $item['app'] = $activity['generator'];
623
624                 return $item;
625         }
626
627         /**
628          * Store hashtags and mentions
629          *
630          * @param array $item
631          */
632         private static function storeFromBody(array $item)
633         {
634                 // Make sure to delete all existing tags (can happen when called via the update functionality)
635                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
636
637                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
638         }
639
640         /**
641          * Generate a GUID out of an URL of an ActivityPub post.
642          *
643          * @param string $url message URL
644          * @return string with GUID
645          */
646         private static function getGUIDByURL(string $url)
647         {
648                 $parsed = parse_url($url);
649
650                 $host_hash = hash('crc32', $parsed['host']);
651
652                 unset($parsed["scheme"]);
653                 unset($parsed["host"]);
654
655                 $path = implode("/", $parsed);
656
657                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
658         }
659
660         /**
661          * Checks if an incoming message is wanted
662          *
663          * @param array $activity
664          * @param array $item
665          * @return boolean Is the message wanted?
666          */
667         private static function isSolicitedMessage(array $activity, array $item)
668         {
669                 // The checks are split to improve the support when searching why a message was accepted.
670                 if (count($activity['receiver']) != 1) {
671                         // The message has more than one receiver, so it is wanted.
672                         Logger::debug('Message has got several receivers - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
673                         return true;
674                 }
675
676                 if ($item['private'] == Item::PRIVATE) {
677                         // We only look at public posts here. Private posts are expected to be intentionally posted to the single receiver.
678                         Logger::debug('Message is private - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
679                         return true;
680                 }
681
682                 if (!empty($activity['from-relay'])) {
683                         // We check relay posts at another place. When it arrived here, the message is already checked.
684                         Logger::debug('Message is a relay post that is already checked - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
685                         return true;
686                 }
687
688                 if (in_array($activity['completion-mode'] ?? Receiver::COMPLETION_NONE, [Receiver::COMPLETION_MANUAL, Receiver::COMPLETION_ANNOUCE])) {
689                         // Manual completions and completions caused by reshares are allowed without any further checks.
690                         Logger::debug('Message is in completion mode - accepted', ['mode' => $activity['completion-mode'], 'uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
691                         return true;
692                 }
693
694                 if ($item['gravity'] != GRAVITY_PARENT) {
695                         // We cannot reliably check at this point if a comment or activity belongs to an accepted post or needs to be fetched
696                         // This can possibly be improved in the future.
697                         Logger::debug('Message is no parent - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
698                         return true;
699                 }
700
701                 $tags = array_column(Tag::getByURIId($item['uri-id'], [Tag::HASHTAG]), 'name');
702                 if (Relay::isSolicitedPost($tags, $item['body'], $item['author-id'], $item['uri'], Protocol::ACTIVITYPUB)) {
703                         Logger::debug('Post is accepted because of the relay settings', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
704                         return true;
705                 } else {
706                         return false;
707                 }
708         }
709
710         /**
711          * Creates an item post
712          *
713          * @param array $activity Activity data
714          * @param array $item     item array
715          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
716          * @throws \ImagickException
717          */
718         public static function postItem(array $activity, array $item)
719         {
720                 if (empty($item)) {
721                         return;
722                 }
723
724                 $stored = false;
725                 ksort($activity['receiver']);
726
727                 if (!self::isSolicitedMessage($activity, $item)) {
728                         DBA::delete('item-uri', ['id' => $item['uri-id']]);
729                         return;
730                 }
731
732                 foreach ($activity['receiver'] as $receiver) {
733                         if ($receiver == -1) {
734                                 continue;
735                         }
736
737                         $item['uid'] = $receiver;
738
739                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
740                         switch($type) {
741                                 case Receiver::TARGET_TO:
742                                         $item['post-reason'] = Item::PR_TO;
743                                         break;
744                                 case Receiver::TARGET_CC:
745                                         $item['post-reason'] = Item::PR_CC;
746                                         break;
747                                 case Receiver::TARGET_BTO:
748                                         $item['post-reason'] = Item::PR_BTO;
749                                         break;
750                                 case Receiver::TARGET_BCC:
751                                         $item['post-reason'] = Item::PR_BCC;
752                                         break;
753                                 case Receiver::TARGET_FOLLOWER:
754                                         $item['post-reason'] = Item::PR_FOLLOWER;
755                                         break;
756                                 case Receiver::TARGET_ANSWER:
757                                         $item['post-reason'] = Item::PR_COMMENT;
758                                         break;
759                                 case Receiver::TARGET_GLOBAL:
760                                         $item['post-reason'] = Item::PR_GLOBAL;
761                                         break;
762                                 default:
763                                         $item['post-reason'] = Item::PR_NONE;
764                         }
765
766                         if (!empty($activity['from-relay'])) {
767                                 $item['post-reason'] = Item::PR_RELAY;
768                         } elseif (!empty($activity['thread-completion'])) {
769                                 $item['post-reason'] = Item::PR_FETCHED;
770                         }
771
772                         if ($item['isForum'] ?? false) {
773                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
774                         } else {
775                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
776                         }
777
778                         if (($receiver != 0) && empty($item['contact-id'])) {
779                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
780                         }
781
782                         if (!empty($activity['directmessage'])) {
783                                 self::postMail($activity, $item);
784                                 continue;
785                         }
786
787                         if (!($item['isForum'] ?? false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) && !Contact::isSharingByURL($activity['author'], $receiver)) {
788                                 if ($item['post-reason'] == Item::PR_BCC) {
789                                         Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id']]);
790                                         continue;
791                                 }
792
793                                 if (
794                                         !empty($activity['thread-children-type'])
795                                         && in_array($activity['thread-children-type'], Receiver::ACTIVITY_TYPES)
796                                         && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') != Item::COMPLETION_LIKE
797                                 ) {
798                                         Logger::info('Top level post from thread completion from a non sharer had been initiated via an activity, ignoring',
799                                                 ['type' => $activity['thread-children-type'], 'user' => $item['uid'], 'causer' => $item['causer-link'], 'author' => $activity['author'], 'url' => $item['uri']]);
800                                         continue;
801                                 }
802                         }
803
804                         $is_forum = false;
805
806                         if ($receiver != 0) {
807                                 $user = User::getById($receiver, ['account-type']);
808                                 if (!empty($user['account-type'])) {
809                                         $is_forum = ($user['account-type'] == User::ACCOUNT_TYPE_COMMUNITY);
810                                 }
811                         }
812
813                         if (!$is_forum && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') == Item::COMPLETION_NONE && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
814                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
815
816                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
817                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
818                                 }
819
820                                 if ($skip) {
821                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
822                                         continue;
823                                 }
824
825                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
826                         }
827
828                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
829                                 $event_id = self::createEvent($activity, $item);
830
831                                 $item = Event::getItemArrayForImportedId($event_id, $item);
832                         }
833
834                         $item_id = Item::insert($item);
835                         if ($item_id) {
836                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
837                         } else {
838                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
839                         }
840
841                         if ($item['uid'] == 0) {
842                                 $stored = $item_id;
843                         }
844                 }
845
846                 // Store send a follow request for every reshare - but only when the item had been stored
847                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
848                         $author = APContact::getByURL($item['owner-link'], false);
849                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
850                         if ($author['type'] != 'Group') {
851                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
852                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
853                         }
854                 }
855         }
856
857         /**
858          * Store tags and mentions into the tag table
859          *
860          * @param integer $uriid
861          * @param array $tags
862          */
863         private static function storeTags(int $uriid, array $tags = null)
864         {
865                 foreach ($tags as $tag) {
866                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
867                                 continue;
868                         }
869
870                         $hash = substr($tag['name'], 0, 1);
871
872                         if ($tag['type'] == 'Mention') {
873                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
874                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
875                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
876                                         $tag['name'] = substr($tag['name'], 1);
877                                 }
878                                 $type = Tag::IMPLICIT_MENTION;
879
880                                 if (!empty($tag['href'])) {
881                                         $apcontact = APContact::getByURL($tag['href']);
882                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
883                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
884                                         }
885                                 }
886                         } elseif ($tag['type'] == 'Hashtag') {
887                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
888                                         $tag['name'] = substr($tag['name'], 1);
889                                 }
890                                 $type = Tag::HASHTAG;
891                         }
892
893                         if (empty($tag['name'])) {
894                                 continue;
895                         }
896
897                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
898                 }
899         }
900
901         public static function storeReceivers(int $uriid, array $receivers)
902         {
903                 foreach (['as:to' => Tag::TO, 'as:cc' => Tag::CC, 'as:bto' => Tag::BTO, 'as:bcc' => Tag::BCC] as $element => $type) {
904                         if (!empty($receivers[$element])) {
905                                 foreach ($receivers[$element] as $receiver) {
906                                         if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
907                                                 $name = Receiver::PUBLIC_COLLECTION;
908                                         } else {
909                                                 $name = trim(parse_url($receiver, PHP_URL_PATH), '/');
910                                         }
911                                         Tag::store($uriid, $type, $name, $receiver);
912                                 }
913                         }
914                 }
915         }
916
917         /**
918          * Creates an mail post
919          *
920          * @param array $activity Activity data
921          * @param array $item     item array
922          * @return int|bool New mail table row id or false on error
923          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
924          */
925         private static function postMail($activity, $item)
926         {
927                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
928                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
929                         return false;
930                 }
931
932                 Logger::info('Direct Message', $item);
933
934                 $msg = [];
935                 $msg['uid'] = $item['uid'];
936
937                 $msg['contact-id'] = $item['contact-id'];
938
939                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
940                 $msg['from-name'] = $contact['name'];
941                 $msg['from-url'] = $contact['url'];
942                 $msg['from-photo'] = $contact['photo'];
943
944                 $msg['uri'] = $item['uri'];
945                 $msg['created'] = $item['created'];
946
947                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
948                 if (DBA::isResult($parent)) {
949                         $msg['parent-uri'] = $parent['parent-uri'];
950                         $msg['title'] = $parent['title'];
951                 } else {
952                         $msg['parent-uri'] = $item['thr-parent'];
953
954                         if (!empty($item['title'])) {
955                                 $msg['title'] = $item['title'];
956                         } elseif (!empty($item['content-warning'])) {
957                                 $msg['title'] = $item['content-warning'];
958                         } else {
959                                 // Trying to generate a title out of the body
960                                 $title = $item['body'];
961
962                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
963                                         $title = $matches[3];
964                                 }
965
966                                 $title = trim(BBCode::toPlaintext($title));
967
968                                 if (strlen($title) > 20) {
969                                         $title = substr($title, 0, 20) . '...';
970                                 }
971
972                                 $msg['title'] = $title;
973                         }
974                 }
975                 $msg['body'] = $item['body'];
976
977                 return Mail::insert($msg);
978         }
979
980         /**
981          * Fetches missing posts
982          *
983          * @param string $url         message URL
984          * @param array  $child       activity array with the child of this message
985          * @param string $relay_actor Relay actor
986          * @param int    $completion  Completion mode, see Receiver::COMPLETION_*
987          * @return string fetched message URL
988          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
989          */
990         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '', int $completion = Receiver::COMPLETION_MANUAL)
991         {
992                 if (!empty($child['receiver'])) {
993                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
994                 } else {
995                         $uid = 0;
996                 }
997
998                 $object = ActivityPub::fetchContent($url, $uid);
999                 if (empty($object)) {
1000                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url]);
1001                         return '';
1002                 }
1003
1004                 if (empty($object['id'])) {
1005                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
1006                         return '';
1007                 }
1008
1009                 if (!empty($object['actor'])) {
1010                         $object_actor = $object['actor'];
1011                 } elseif (!empty($object['attributedTo'])) {
1012                         $object_actor = $object['attributedTo'];
1013                         if (is_array($object_actor)) {
1014                                 $compacted = JsonLD::compact($object);
1015                                 $object_actor = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
1016                         }
1017                 } else {
1018                         // Shouldn't happen
1019                         $object_actor = '';
1020                 }
1021
1022                 $signer = [$object_actor];
1023
1024                 if (!empty($child['author'])) {
1025                         $actor = $child['author'];
1026                         $signer[] = $actor;
1027                 } else {
1028                         $actor = $object_actor;
1029                 }
1030
1031                 if (!empty($object['published'])) {
1032                         $published = $object['published'];
1033                 } elseif (!empty($child['published'])) {
1034                         $published = $child['published'];
1035                 } else {
1036                         $published = DateTimeFormat::utcNow();
1037                 }
1038
1039                 $activity = [];
1040                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
1041                 unset($object['@context']);
1042                 $activity['id'] = $object['id'];
1043                 $activity['to'] = $object['to'] ?? [];
1044                 $activity['cc'] = $object['cc'] ?? [];
1045                 $activity['actor'] = $actor;
1046                 $activity['object'] = $object;
1047                 $activity['published'] = $published;
1048                 $activity['type'] = 'Create';
1049
1050                 $ldactivity = JsonLD::compact($activity);
1051
1052                 if (!empty($relay_actor)) {
1053                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
1054                         $ldactivity['completion-mode']   = Receiver::COMPLETION_RELAY;
1055                 } elseif (!empty($child['thread-completion'])) {
1056                         $ldactivity['thread-completion'] = $child['thread-completion'];
1057                         $ldactivity['completion-mode']   = $child['completion-mode'] ?? Receiver::COMPLETION_NONE;
1058                 } else {
1059                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
1060                         $ldactivity['completion-mode']   = $completion;
1061                 }
1062
1063                 if (!empty($child['type'])) {
1064                         $ldactivity['thread-children-type'] = $child['type'];
1065                 }
1066
1067                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
1068                         return '';
1069                 }
1070
1071                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), $uid, true, false, $signer);
1072
1073                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
1074
1075                 return $activity['id'];
1076         }
1077
1078         /**
1079          * Test if incoming relay messages should be accepted
1080          *
1081          * @param array $activity activity array
1082          * @param string $id      object ID
1083          * @return boolean true if message is accepted
1084          */
1085         private static function acceptIncomingMessage(array $activity, string $id)
1086         {
1087                 if (empty($activity['as:object'])) {
1088                         Logger::info('No object field in activity - accepted', ['id' => $id]);
1089                         return true;
1090                 }
1091
1092                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
1093                 $uriid = ItemURI::getIdByURI($replyto);
1094                 if (Post::exists(['uri-id' => $uriid])) {
1095                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
1096                         return true;
1097                 }
1098
1099                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
1100                 $authorid = Contact::getIdForURL($attributed_to);
1101
1102                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value'));
1103
1104                 $messageTags = [];
1105                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
1106                 if (!empty($tags)) {
1107                         foreach ($tags as $tag) {
1108                                 if ($tag['type'] != 'Hashtag') {
1109                                         continue;
1110                                 }
1111                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
1112                         }
1113                 }
1114
1115                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
1116         }
1117
1118         /**
1119          * perform a "follow" request
1120          *
1121          * @param array $activity
1122          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1123          * @throws \ImagickException
1124          */
1125         public static function followUser($activity)
1126         {
1127                 $uid = User::getIdForURL($activity['object_id']);
1128                 if (empty($uid)) {
1129                         return;
1130                 }
1131
1132                 $owner = User::getOwnerDataById($uid);
1133                 if (empty($owner)) {
1134                         return;
1135                 }
1136
1137                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1138                 if (!empty($cid)) {
1139                         self::switchContact($cid);
1140                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1141                 }
1142
1143                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
1144                         'author-link' => $activity['actor']];
1145
1146                 // Ensure that the contact has got the right network type
1147                 self::switchContact($item['author-id']);
1148
1149                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
1150                 if ($result === true) {
1151                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
1152                 }
1153
1154                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1155                 if (empty($cid)) {
1156                         return;
1157                 }
1158
1159                 if (empty($contact)) {
1160                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1161                 }
1162
1163                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1164         }
1165
1166         /**
1167          * Update the given profile
1168          *
1169          * @param array $activity
1170          * @throws \Exception
1171          */
1172         public static function updatePerson($activity)
1173         {
1174                 if (empty($activity['object_id'])) {
1175                         return;
1176                 }
1177
1178                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
1179                 Contact::updateFromProbeByURL($activity['object_id']);
1180         }
1181
1182         /**
1183          * Delete the given profile
1184          *
1185          * @param array $activity
1186          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1187          */
1188         public static function deletePerson($activity)
1189         {
1190                 if (empty($activity['object_id']) || empty($activity['actor'])) {
1191                         Logger::info('Empty object id or actor.');
1192                         return;
1193                 }
1194
1195                 if ($activity['object_id'] != $activity['actor']) {
1196                         Logger::info('Object id does not match actor.');
1197                         return;
1198                 }
1199
1200                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
1201                 while ($contact = DBA::fetch($contacts)) {
1202                         Contact::remove($contact['id']);
1203                 }
1204                 DBA::close($contacts);
1205
1206                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
1207         }
1208
1209         /**
1210          * Blocks the user by the contact
1211          *
1212          * @param array $activity
1213          * @throws \Exception
1214          */
1215         public static function blockAccount($activity)
1216         {
1217                 $cid = Contact::getIdForURL($activity['actor']);
1218                 if (empty($cid)) {
1219                         return;
1220                 }
1221
1222                 $uid = User::getIdForURL($activity['object_id']);
1223                 if (empty($uid)) {
1224                         return;                 
1225                 }
1226
1227                 Contact\User::setIsBlocked($cid, $uid, true);
1228
1229                 Logger::info('Contact blocked user', ['contact' => $cid, 'user' => $uid]);
1230         }
1231
1232         /**
1233          * Unblocks the user by the contact
1234          *
1235          * @param array $activity
1236          * @throws \Exception
1237          */
1238         public static function unblockAccount($activity)
1239         {
1240                 $cid = Contact::getIdForURL($activity['actor']);
1241                 if (empty($cid)) {
1242                         return;
1243                 }
1244
1245                 $uid = User::getIdForURL($activity['object_object']);
1246                 if (empty($uid)) {
1247                         return;                 
1248                 }
1249
1250                 Contact\User::setIsBlocked($cid, $uid, false);
1251
1252                 Logger::info('Contact unblocked user', ['contact' => $cid, 'user' => $uid]);
1253         }
1254
1255         /**
1256          * Accept a follow request
1257          *
1258          * @param array $activity
1259          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1260          * @throws \ImagickException
1261          */
1262         public static function acceptFollowUser($activity)
1263         {
1264                 $uid = User::getIdForURL($activity['object_actor']);
1265                 if (empty($uid)) {
1266                         return;
1267                 }
1268
1269                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1270                 if (empty($cid)) {
1271                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1272                         return;
1273                 }
1274
1275                 self::switchContact($cid);
1276
1277                 $fields = ['pending' => false];
1278
1279                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1280                 if ($contact['rel'] == Contact::FOLLOWER) {
1281                         $fields['rel'] = Contact::FRIEND;
1282                 }
1283
1284                 $condition = ['id' => $cid];
1285                 Contact::update($fields, $condition);
1286                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1287         }
1288
1289         /**
1290          * Reject a follow request
1291          *
1292          * @param array $activity
1293          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1294          * @throws \ImagickException
1295          */
1296         public static function rejectFollowUser($activity)
1297         {
1298                 $uid = User::getIdForURL($activity['object_actor']);
1299                 if (empty($uid)) {
1300                         return;
1301                 }
1302
1303                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1304                 if (empty($cid)) {
1305                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1306                         return;
1307                 }
1308
1309                 self::switchContact($cid);
1310
1311                 $contact = Contact::getById($cid, ['rel']);
1312                 if ($contact['rel'] == Contact::SHARING) {
1313                         Contact::remove($cid);
1314                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1315                 } elseif ($contact['rel'] == Contact::FRIEND) {
1316                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1317                 } else {
1318                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1319                 }
1320         }
1321
1322         /**
1323          * Undo activity like "like" or "dislike"
1324          *
1325          * @param array $activity
1326          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1327          * @throws \ImagickException
1328          */
1329         public static function undoActivity($activity)
1330         {
1331                 if (empty($activity['object_id'])) {
1332                         return;
1333                 }
1334
1335                 if (empty($activity['object_actor'])) {
1336                         return;
1337                 }
1338
1339                 $author_id = Contact::getIdForURL($activity['object_actor']);
1340                 if (empty($author_id)) {
1341                         return;
1342                 }
1343
1344                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1345         }
1346
1347         /**
1348          * Activity to remove a follower
1349          *
1350          * @param array $activity
1351          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1352          * @throws \ImagickException
1353          */
1354         public static function undoFollowUser($activity)
1355         {
1356                 $uid = User::getIdForURL($activity['object_object']);
1357                 if (empty($uid)) {
1358                         return;
1359                 }
1360
1361                 $owner = User::getOwnerDataById($uid);
1362                 if (empty($owner)) {
1363                         return;
1364                 }
1365
1366                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1367                 if (empty($cid)) {
1368                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1369                         return;
1370                 }
1371
1372                 self::switchContact($cid);
1373
1374                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1375                 if (!DBA::isResult($contact)) {
1376                         return;
1377                 }
1378
1379                 Contact::removeFollower($contact);
1380                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1381         }
1382
1383         /**
1384          * Switches a contact to AP if needed
1385          *
1386          * @param integer $cid Contact ID
1387          * @throws \Exception
1388          */
1389         private static function switchContact($cid)
1390         {
1391                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1392                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1393                         return;
1394                 }
1395
1396                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1397                 Contact::updateFromProbe($cid);
1398         }
1399
1400         /**
1401          * Collects implicit mentions like:
1402          * - the author of the parent item
1403          * - all the mentioned conversants in the parent item
1404          *
1405          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1406          * @return array
1407          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1408          */
1409         private static function getImplicitMentionList(array $parent)
1410         {
1411                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1412
1413                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1414
1415                 $implicit_mentions = [];
1416                 if (empty($parent_author['url'])) {
1417                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1418                 } else {
1419                         $implicit_mentions[] = $parent_author['url'];
1420                         $implicit_mentions[] = $parent_author['nurl'];
1421                         $implicit_mentions[] = $parent_author['alias'];
1422                 }
1423
1424                 if (!empty($parent['alias'])) {
1425                         $implicit_mentions[] = $parent['alias'];
1426                 }
1427
1428                 foreach ($parent_terms as $term) {
1429                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1430                         if (!empty($contact['url'])) {
1431                                 $implicit_mentions[] = $contact['url'];
1432                                 $implicit_mentions[] = $contact['nurl'];
1433                                 $implicit_mentions[] = $contact['alias'];
1434                         }
1435                 }
1436
1437                 return $implicit_mentions;
1438         }
1439
1440         /**
1441          * Strips from the body prepended implicit mentions
1442          *
1443          * @param string $body
1444          * @param array $parent
1445          * @return string
1446          */
1447         private static function removeImplicitMentionsFromBody(string $body, array $parent)
1448         {
1449                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1450                         return $body;
1451                 }
1452
1453                 $potential_mentions = self::getImplicitMentionList($parent);
1454
1455                 $kept_mentions = [];
1456
1457                 // Extract one prepended mention at a time from the body
1458                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1459                         if (!in_array($matches[2], $potential_mentions)) {
1460                                 $kept_mentions[] = $matches[1];
1461                         }
1462
1463                         $body = $matches[3];
1464                 }
1465
1466                 // Re-appending the kept mentions to the body after extraction
1467                 $kept_mentions[] = $body;
1468
1469                 return implode('', $kept_mentions);
1470         }
1471
1472         /**
1473          * Adds links to string mentions
1474          *
1475          * @param string $body
1476          * @param array  $tags
1477          * @return string
1478          */
1479         protected static function addMentionLinks(string $body, array $tags): string
1480         {
1481                 // This prevents links to be added again to Pleroma-style mention links
1482                 $body = self::normalizeMentionLinks($body);
1483
1484                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
1485                         foreach ($tags as $tag) {
1486                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1487                                         continue;
1488                                 }
1489
1490                                 $hash = substr($tag['name'], 0, 1);
1491                                 $name = substr($tag['name'], 1);
1492                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
1493                                         $hash = '';
1494                                         $name = $tag['name'];
1495                                 }
1496
1497                                 $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
1498                         }
1499
1500                         return $body;
1501                 });
1502
1503                 return $body;
1504         }
1505 }