src/Model/Contact/Relation.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   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\Model\Contact;
  23
  24 use Exception;
  25 use Friendica\Core\Logger;
  26 use Friendica\Core\Protocol;
  27 use Friendica\Database\Database;
  28 use Friendica\Database\DBA;
  29 use Friendica\DI;
  30 use Friendica\Model\APContact;
  31 use Friendica\Model\Contact;
  32 use Friendica\Model\Profile;
  33 use Friendica\Model\User;
  34 use Friendica\Protocol\ActivityPub;
  35 use Friendica\Util\DateTimeFormat;
  36 use Friendica\Util\Strings;
  37
  38 /**
  39  * This class provides relationship information based on the `contact-relation` table.
  40  * This table is directional (cid = source, relation-cid = target), references public contacts (with uid=0) and records both
  41  * follows and the last interaction (likes/comments) on public posts.
  42  */
  43 class Relation
  44 {
  45         /**
  46          * No discovery of followers/followings
  47          */
  48         const DISCOVERY_NONE = 0;
  49         /**
  50          * Discover followers/followings of local contacts
  51          */
  52         const DISCOVERY_LOCAL = 1;
  53         /**
  54          * Discover followers/followings of local contacts and contacts that visibly interacted on the system
  55          */
  56         const DISCOVERY_INTERACTOR = 2;
  57         /**
  58          * Discover followers/followings of all contacts
  59          */
  60         const DISCOVERY_ALL = 3;
  61
  62         public static function store(int $target, int $actor, string $interaction_date)
  63         {
  64                 if ($actor == $target) {
  65                         return;
  66                 }
  67
  68                 DBA::insert('contact-relation', ['last-interaction' => $interaction_date, 'cid' => $target, 'relation-cid' => $actor], Database::INSERT_UPDATE);
  69         }
  70
  71         /**
  72          * Fetches the followers of a given profile and adds them
  73          *
  74          * @param string $url URL of a profile
  75          * @return void
  76          */
  77         public static function discoverByUrl(string $url)
  78         {
  79                 $contact = Contact::getByURL($url);
  80                 if (empty($contact)) {
  81                         return;
  82                 }
  83
  84                 if (!self::isDiscoverable($url, $contact)) {
  85                         return;
  86                 }
  87
  88                 $uid = User::getIdForURL($url);
  89                 if (!empty($uid)) {
  90                         // Fetch the followers/followings locally
  91                         $followers = self::getContacts($uid, [Contact::FOLLOWER, Contact::FRIEND]);
  92                         $followings = self::getContacts($uid, [Contact::SHARING, Contact::FRIEND]);
  93                 } else {
  94                         $apcontact = APContact::getByURL($url, false);
  95
  96                         if (!empty($apcontact['followers']) && is_string($apcontact['followers'])) {
  97                                 $followers = ActivityPub::fetchItems($apcontact['followers']);
  98                         } else {
  99                                 $followers = [];
 100                         }
 101
 102                         if (!empty($apcontact['following']) && is_string($apcontact['following'])) {
 103                                 $followings = ActivityPub::fetchItems($apcontact['following']);
 104                         } else {
 105                                 $followings = [];
 106                         }
 107                 }
 108
 109                 if (empty($followers) && empty($followings)) {
 110                         DBA::update('contact', ['last-discovery' => DateTimeFormat::utcNow()], ['id' => $contact['id']]);
 111                         Logger::info('The contact does not offer discoverable data', ['id' => $contact['id'], 'url' => $url, 'network' => $contact['network']]);
 112                         return;
 113                 }
 114
 115                 $target = $contact['id'];
 116
 117                 if (!empty($followers)) {
 118                         // Clear the follower list, since it will be recreated in the next step
 119                         DBA::update('contact-relation', ['follows' => false], ['cid' => $target]);
 120                 }
 121
 122                 $contacts = [];
 123                 foreach (array_merge($followers, $followings) as $contact) {
 124                         if (is_string($contact)) {
 125                                 $contacts[] = $contact;
 126                         } elseif (!empty($contact['url']) && is_string($contact['url'])) {
 127                                 $contacts[] = $contact['url'];
 128                         }
 129                 }
 130                 $contacts = array_unique($contacts);
 131
 132                 $follower_counter = 0;
 133                 $following_counter = 0;
 134
 135                 Logger::info('Discover contacts', ['id' => $target, 'url' => $url, 'contacts' => count($contacts)]);
 136                 foreach ($contacts as $contact) {
 137                         $actor = Contact::getIdForURL($contact);
 138                         if (!empty($actor)) {
 139                                 if (in_array($contact, $followers)) {
 140                                         $condition = ['cid' => $target, 'relation-cid' => $actor];
 141                                         DBA::insert('contact-relation', $condition, Database::INSERT_IGNORE);
 142                                         DBA::update('contact-relation', ['follows' => true, 'follow-updated' => DateTimeFormat::utcNow()], $condition);
 143                                         $follower_counter++;
 144                                 }
 145
 146                                 if (in_array($contact, $followings)) {
 147                                         $condition = ['cid' => $actor, 'relation-cid' => $target];
 148                                         DBA::insert('contact-relation', $condition, Database::INSERT_IGNORE);
 149                                         DBA::update('contact-relation', ['follows' => true, 'follow-updated' => DateTimeFormat::utcNow()], $condition);
 150                                         $following_counter++;
 151                                 }
 152                         }
 153                 }
 154
 155                 if (!empty($followers)) {
 156                         // Delete all followers that aren't followers anymore (and aren't interacting)
 157                         DBA::delete('contact-relation', ['cid' => $target, 'follows' => false, 'last-interaction' => DBA::NULL_DATETIME]);
 158                 }
 159
 160                 DBA::update('contact', ['last-discovery' => DateTimeFormat::utcNow()], ['id' => $target]);
 161                 Logger::info('Contacts discovery finished', ['id' => $target, 'url' => $url, 'follower' => $follower_counter, 'following' => $following_counter]);
 162                 return;
 163         }
 164
 165         /**
 166          * Fetch contact url list from the given local user
 167          *
 168          * @param integer $uid
 169          * @param array $rel
 170          * @return array contact list
 171          */
 172         private static function getContacts(int $uid, array $rel)
 173         {
 174                 $list = [];
 175                 $profile = Profile::getByUID($uid);
 176                 if (!empty($profile['hide-friends'])) {
 177                         return $list;
 178                 }
 179
 180                 $condition = ['rel' => $rel, 'uid' => $uid, 'self' => false, 'deleted' => false,
 181                         'hidden' => false, 'archive' => false, 'pending' => false];
 182                 $condition = DBA::mergeConditions($condition, ["`url` IN (SELECT `url` FROM `apcontact`)"]);
 183                 $contacts = DBA::select('contact', ['url'], $condition);
 184                 while ($contact = DBA::fetch($contacts)) {
 185                         $list[] = $contact['url'];
 186                 }
 187                 DBA::close($contacts);
 188
 189                 return $list;
 190         }
 191
 192         /**
 193          * Tests if a given contact url is discoverable
 194          *
 195          * @param string $url     Contact url
 196          * @param array  $contact Contact array
 197          * @return boolean True if contact is discoverable
 198          */
 199         public static function isDiscoverable(string $url, array $contact = [])
 200         {
 201                 $contact_discovery = DI::config()->get('system', 'contact_discovery');
 202
 203                 if ($contact_discovery == self::DISCOVERY_NONE) {
 204                         return false;
 205                 }
 206
 207                 if (empty($contact)) {
 208                         $contact = Contact::getByURL($url, false);
 209                 }
 210
 211                 if (empty($contact)) {
 212                         return false;
 213                 }
 214
 215                 if ($contact['last-discovery'] > DateTimeFormat::utc('now - 1 month')) {
 216                         Logger::info('No discovery - Last was less than a month ago.', ['id' => $contact['id'], 'url' => $url, 'discovery' => $contact['last-discovery']]);
 217                         return false;
 218                 }
 219
 220                 if ($contact_discovery != self::DISCOVERY_ALL) {
 221                         $local = DBA::exists('contact', ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($url), 0]);
 222                         if (($contact_discovery == self::DISCOVERY_LOCAL) && !$local) {
 223                                 Logger::info('No discovery - This contact is not followed/following locally.', ['id' => $contact['id'], 'url' => $url]);
 224                                 return false;
 225                         }
 226
 227                         if ($contact_discovery == self::DISCOVERY_INTERACTOR) {
 228                                 $interactor = DBA::exists('contact-relation', ["`relation-cid` = ? AND `last-interaction` > ?", $contact['id'], DBA::NULL_DATETIME]);
 229                                 if (!$local && !$interactor) {
 230                                         Logger::info('No discovery - This contact is not interacting locally.', ['id' => $contact['id'], 'url' => $url]);
 231                                         return false;
 232                                 }
 233                         }
 234                 } elseif ($contact['created'] > DateTimeFormat::utc('now - 1 day')) {
 235                         // Newly created contacts are not discovered to avoid DDoS attacks
 236                         Logger::info('No discovery - Contact record is less than a day old.', ['id' => $contact['id'], 'url' => $url, 'discovery' => $contact['created']]);
 237                         return false;
 238                 }
 239
 240                 if (!in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN, Protocol::OSTATUS])) {
 241                         $apcontact = APContact::getByURL($url, false);
 242                         if (empty($apcontact)) {
 243                                 Logger::info('No discovery - The contact does not seem to speak ActivityPub.', ['id' => $contact['id'], 'url' => $url, 'network' => $contact['network']]);
 244                                 return false;
 245                         }
 246                 }
 247
 248                 return true;
 249         }
 250
 251         /**
 252          * @param int $uid   user
 253          * @param int $start optional, default 0
 254          * @param int $limit optional, default 80
 255          * @return array
 256          */
 257         static public function getSuggestions(int $uid, int $start = 0, int $limit = 80)
 258         {
 259                 $cid = Contact::getPublicIdByUserId($uid);
 260                 $totallimit = $start + $limit;
 261                 $contacts = [];
 262
 263                 Logger::info('Collecting suggestions', ['uid' => $uid, 'cid' => $cid, 'start' => $start, 'limit' => $limit]);
 264
 265                 $diaspora = DI::config()->get('system', 'diaspora_enabled') ? Protocol::DIASPORA : Protocol::ACTIVITYPUB;
 266                 $ostatus = !DI::config()->get('system', 'ostatus_disabled') ? Protocol::OSTATUS : Protocol::ACTIVITYPUB;
 267
 268                 // The query returns contacts where contacts interacted with whom the given user follows.
 269                 // Contacts who already are in the user's contact table are ignored.
 270                 $results = DBA::select('contact', [],
 271                         ["`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` IN
 272                                 (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ?)
 273                                         AND NOT `cid` IN (SELECT `id` FROM `contact` WHERE `uid` = ? AND `nurl` IN
 274                                                 (SELECT `nurl` FROM `contact` WHERE `uid` = ? AND `rel` IN (?, ?))))
 275                         AND NOT `hidden` AND `network` IN (?, ?, ?, ?)",
 276                         $cid, 0, $uid, Contact::FRIEND, Contact::SHARING,
 277                         Protocol::ACTIVITYPUB, Protocol::DFRN, $diaspora, $ostatus],
 278                         ['order' => ['last-item' => true], 'limit' => $totallimit]
 279                 );
 280
 281                 while ($contact = DBA::fetch($results)) {
 282                         $contacts[$contact['id']] = $contact;
 283                 }
 284                 DBA::close($results);
 285
 286                 Logger::info('Contacts of contacts who are followed by the given user', ['uid' => $uid, 'cid' => $cid, 'count' => count($contacts)]);
 287
 288                 if (count($contacts) >= $totallimit) {
 289                         return array_slice($contacts, $start, $limit);
 290                 }
 291
 292                 // The query returns contacts where contacts interacted with whom also interacted with the given user.
 293                 // Contacts who already are in the user's contact table are ignored.
 294                 $results = DBA::select('contact', [],
 295                         ["`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` IN
 296                                 (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ?)
 297                                         AND NOT `cid` IN (SELECT `id` FROM `contact` WHERE `uid` = ? AND `nurl` IN
 298                                                 (SELECT `nurl` FROM `contact` WHERE `uid` = ? AND `rel` IN (?, ?))))
 299                         AND NOT `hidden` AND `network` IN (?, ?, ?, ?)",
 300                         $cid, 0, $uid, Contact::FRIEND, Contact::SHARING,
 301                         Protocol::ACTIVITYPUB, Protocol::DFRN, $diaspora, $ostatus],
 302                         ['order' => ['last-item' => true], 'limit' => $totallimit]
 303                 );
 304
 305                 while ($contact = DBA::fetch($results)) {
 306                         $contacts[$contact['id']] = $contact;
 307                 }
 308                 DBA::close($results);
 309
 310                 Logger::info('Contacts of contacts who are following the given user', ['uid' => $uid, 'cid' => $cid, 'count' => count($contacts)]);
 311
 312                 if (count($contacts) >= $totallimit) {
 313                         return array_slice($contacts, $start, $limit);
 314                 }
 315
 316                 // The query returns contacts that follow the given user but aren't followed by that user.
 317                 $results = DBA::select('contact', [],
 318                         ["`nurl` IN (SELECT `nurl` FROM `contact` WHERE `uid` = ? AND `rel` = ?)
 319                         AND NOT `hidden` AND `uid` = ? AND `network` IN (?, ?, ?, ?)",
 320                         $uid, Contact::FOLLOWER, 0,
 321                         Protocol::ACTIVITYPUB, Protocol::DFRN, $diaspora, $ostatus],
 322                         ['order' => ['last-item' => true], 'limit' => $totallimit]
 323                 );
 324
 325                 while ($contact = DBA::fetch($results)) {
 326                         $contacts[$contact['id']] = $contact;
 327                 }
 328                 DBA::close($results);
 329
 330                 Logger::info('Followers that are not followed by the given user', ['uid' => $uid, 'cid' => $cid, 'count' => count($contacts)]);
 331
 332                 if (count($contacts) >= $totallimit) {
 333                         return array_slice($contacts, $start, $limit);
 334                 }
 335
 336                 // The query returns any contact that isn't followed by that user.
 337                 $results = DBA::select('contact', [],
 338                         ["NOT `nurl` IN (SELECT `nurl` FROM `contact` WHERE `uid` = ? AND `rel` IN (?, ?))
 339                         AND NOT `hidden` AND `uid` = ? AND `network` IN (?, ?, ?, ?)",
 340                         $uid, Contact::FRIEND, Contact::SHARING, 0,
 341                         Protocol::ACTIVITYPUB, Protocol::DFRN, $diaspora, $ostatus],
 342                         ['order' => ['last-item' => true], 'limit' => $totallimit]
 343                 );
 344
 345                 while ($contact = DBA::fetch($results)) {
 346                         $contacts[$contact['id']] = $contact;
 347                 }
 348                 DBA::close($results);
 349
 350                 Logger::info('Any contact', ['uid' => $uid, 'cid' => $cid, 'count' => count($contacts)]);
 351
 352                 return array_slice($contacts, $start, $limit);
 353         }
 354
 355         /**
 356          * Counts all the known follows of the provided public contact
 357          *
 358          * @param int   $cid       Public contact id
 359          * @param array $condition Additional condition on the contact table
 360          * @return int
 361          * @throws Exception
 362          */
 363         public static function countFollows(int $cid, array $condition = [])
 364         {
 365                 $condition = DBA::mergeConditions($condition,
 366                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)',
 367                         $cid]
 368                 );
 369
 370                 return DI::dba()->count('contact', $condition);
 371         }
 372
 373         /**
 374          * Returns a paginated list of contacts that are followed the provided public contact.
 375          *
 376          * @param int   $cid       Public contact id
 377          * @param array $condition Additional condition on the contact table
 378          * @param int   $count
 379          * @param int   $offset
 380          * @param bool  $shuffle
 381          * @return array
 382          * @throws Exception
 383          */
 384         public static function listFollows(int $cid, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 385         {
 386                 $condition = DBA::mergeConditions($condition,
 387                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)',
 388                         $cid]
 389                 );
 390
 391                 return DI::dba()->selectToArray('contact', [], $condition,
 392                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 393                 );
 394         }
 395
 396         /**
 397          * Counts all the known followers of the provided public contact
 398          *
 399          * @param int   $cid       Public contact id
 400          * @param array $condition Additional condition on the contact table
 401          * @return int
 402          * @throws Exception
 403          */
 404         public static function countFollowers(int $cid, array $condition = [])
 405         {
 406                 $condition = DBA::mergeConditions($condition,
 407                         ['`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)',
 408                         $cid]
 409                 );
 410
 411                 return DI::dba()->count('contact', $condition);
 412         }
 413
 414         /**
 415          * Returns a paginated list of contacts that follow the provided public contact.
 416          *
 417          * @param int   $cid       Public contact id
 418          * @param array $condition Additional condition on the contact table
 419          * @param int   $count
 420          * @param int   $offset
 421          * @param bool  $shuffle
 422          * @return array
 423          * @throws Exception
 424          */
 425         public static function listFollowers(int $cid, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 426         {
 427                 $condition = DBA::mergeConditions($condition,
 428                         ['`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)', $cid]
 429                 );
 430
 431                 return DI::dba()->selectToArray('contact', [], $condition,
 432                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 433                 );
 434         }
 435
 436         /**
 437          * Counts the number of contacts that are known mutuals with the provided public contact.
 438          *
 439          * @param int   $cid       Public contact id
 440          * @param array $condition Additional condition array on the contact table
 441          * @return int
 442          * @throws Exception
 443          */
 444         public static function countMutuals(int $cid, array $condition = [])
 445         {
 446                 $condition = DBA::mergeConditions($condition,
 447                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 448                         AND `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)',
 449                         $cid, $cid]
 450                 );
 451
 452                 return DI::dba()->count('contact', $condition);
 453         }
 454
 455         /**
 456          * Returns a paginated list of contacts that are known mutuals with the provided public contact.
 457          *
 458          * @param int   $cid       Public contact id
 459          * @param array $condition Additional condition on the contact table
 460          * @param int   $count
 461          * @param int   $offset
 462          * @param bool  $shuffle
 463          * @return array
 464          * @throws Exception
 465          */
 466         public static function listMutuals(int $cid, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 467         {
 468                 $condition = DBA::mergeConditions($condition,
 469                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 470                         AND `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)',
 471                         $cid, $cid]
 472                 );
 473
 474                 return DI::dba()->selectToArray('contact', [], $condition,
 475                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 476                 );
 477         }
 478
 479
 480         /**
 481          * Counts the number of contacts with any relationship with the provided public contact.
 482          *
 483          * @param int   $cid       Public contact id
 484          * @param array $condition Additional condition array on the contact table
 485          * @return int
 486          * @throws Exception
 487          */
 488         public static function countAll(int $cid, array $condition = [])
 489         {
 490                 $condition = DBA::mergeConditions($condition,
 491                         ['(`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 492                         OR `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`))',
 493                                 $cid, $cid]
 494                 );
 495
 496                 return DI::dba()->count('contact', $condition);
 497         }
 498
 499         /**
 500          * Returns a paginated list of contacts with any relationship with the provided public contact.
 501          *
 502          * @param int   $cid       Public contact id
 503          * @param array $condition Additional condition on the contact table
 504          * @param int   $count
 505          * @param int   $offset
 506          * @param bool  $shuffle
 507          * @return array
 508          * @throws Exception
 509          */
 510         public static function listAll(int $cid, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 511         {
 512                 $condition = DBA::mergeConditions($condition,
 513                         ['(`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 514                         OR `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`))',
 515                                 $cid, $cid]
 516                 );
 517
 518                 return DI::dba()->selectToArray('contact', [], $condition,
 519                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 520                 );
 521         }
 522
 523         /**
 524          * Counts the number of contacts that both provided public contacts have interacted with at least once.
 525          * Interactions include follows and likes and comments on public posts.
 526          *
 527          * @param int   $sourceId  Public contact id
 528          * @param int   $targetId  Public contact id
 529          * @param array $condition Additional condition array on the contact table
 530          * @return int
 531          * @throws Exception
 532          */
 533         public static function countCommon(int $sourceId, int $targetId, array $condition = [])
 534         {
 535                 $condition = DBA::mergeConditions($condition,
 536                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ?)
 537                         AND `id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ?)',
 538                         $sourceId, $targetId]
 539                 );
 540
 541                 return DI::dba()->count('contact', $condition);
 542         }
 543
 544         /**
 545          * Returns a paginated list of contacts that both provided public contacts have interacted with at least once.
 546          * Interactions include follows and likes and comments on public posts.
 547          *
 548          * @param int   $sourceId  Public contact id
 549          * @param int   $targetId  Public contact id
 550          * @param array $condition Additional condition on the contact table
 551          * @param int   $count
 552          * @param int   $offset
 553          * @param bool  $shuffle
 554          * @return array
 555          * @throws Exception
 556          */
 557         public static function listCommon(int $sourceId, int $targetId, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 558         {
 559                 $condition = DBA::mergeConditions($condition,
 560                         ["`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ?)
 561                         AND `id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ?)",
 562                         $sourceId, $targetId]
 563                 );
 564
 565                 return DI::dba()->selectToArray('contact', [], $condition,
 566                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 567                 );
 568         }
 569
 570         /**
 571          * Counts the number of contacts that are followed by both provided public contacts.
 572          *
 573          * @param int   $sourceId  Public contact id
 574          * @param int   $targetId  Public contact id
 575          * @param array $condition Additional condition array on the contact table
 576          * @return int
 577          * @throws Exception
 578          */
 579         public static function countCommonFollows(int $sourceId, int $targetId, array $condition = [])
 580         {
 581                 $condition = DBA::mergeConditions($condition,
 582                         ['`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 583                         AND `id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)',
 584                         $sourceId, $targetId]
 585                 );
 586
 587                 return DI::dba()->count('contact', $condition);
 588         }
 589
 590         /**
 591          * Returns a paginated list of contacts that are followed by both provided public contacts.
 592          *
 593          * @param int   $sourceId  Public contact id
 594          * @param int   $targetId  Public contact id
 595          * @param array $condition Additional condition array on the contact table
 596          * @param int   $count
 597          * @param int   $offset
 598          * @param bool  $shuffle
 599          * @return array
 600          * @throws Exception
 601          */
 602         public static function listCommonFollows(int $sourceId, int $targetId, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 603         {
 604                 $condition = DBA::mergeConditions($condition,
 605                         ["`id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)
 606                         AND `id` IN (SELECT `relation-cid` FROM `contact-relation` WHERE `cid` = ? AND `follows`)",
 607                         $sourceId, $targetId]
 608                 );
 609
 610                 return DI::dba()->selectToArray('contact', [], $condition,
 611                         ['limit' => [$offset, $count], 'order' => [$shuffle ? 'RAND()' : 'name']]
 612                 );
 613         }
 614
 615         /**
 616          * Counts the number of contacts that follow both provided public contacts.
 617          *
 618          * @param int   $sourceId  Public contact id
 619          * @param int   $targetId  Public contact id
 620          * @param array $condition Additional condition on the contact table
 621          * @return int
 622          * @throws Exception
 623          */
 624         public static function countCommonFollowers(int $sourceId, int $targetId, array $condition = [])
 625         {
 626                 $condition = DBA::mergeConditions($condition,
 627                         ["`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)
 628                         AND `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)",
 629                         $sourceId, $targetId]
 630                 );
 631
 632                 return DI::dba()->count('contact', $condition);
 633         }
 634
 635         /**
 636          * Returns a paginated list of contacts that follow both provided public contacts.
 637          *
 638          * @param int   $sourceId  Public contact id
 639          * @param int   $targetId  Public contact id
 640          * @param array $condition Additional condition on the contact table
 641          * @param int   $count
 642          * @param int   $offset
 643          * @param bool  $shuffle
 644          * @return array
 645          * @throws Exception
 646          */
 647         public static function listCommonFollowers(int $sourceId, int $targetId, array $condition = [], int $count = 30, int $offset = 0, bool $shuffle = false)
 648         {
 649                 $condition = DBA::mergeConditions($condition,
 650                         ["`id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)
 651                         AND `id` IN (SELECT `cid` FROM `contact-relation` WHERE `relation-cid` = ? AND `follows`)",
 652                         $sourceId, $targetId]
 653                 );
 654
 655                 return DI::dba()->selectToArray('contact', [], $condition,
 656                         ['limit' => [$offset, $count],  'order' => [$shuffle ? 'RAND()' : 'name']]
 657                 );
 658         }
 659 }