SubscriptionsService.php

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<?php

namespace Elgg\Notifications;

use Elgg\Database;
use Elgg\Database\RelationshipsTable;
use Elgg\Database\Select;
use Elgg\Database\Delete;
use Elgg\Database\QueryBuilder;
use Elgg\Database\Entities;
use Elgg\EventsService;
use Elgg\Exceptions\InvalidArgumentException;

class SubscriptionsService {

    const RELATIONSHIP_PREFIX = 'notify';

    const MUTE_NOTIFICATIONS_RELATIONSHIP = 'mute_notifications';
    
    protected $db;
    
    protected $relationshipsTable;
    
    protected $events;

    public function __construct(Database $db, RelationshipsTable $relationshipsTable, EventsService $events) {
        $this->db = $db;
        $this->relationshipsTable = $relationshipsTable;
        $this->events = $events;
    }

    public function getNotificationEventSubscriptions(NotificationEvent $event, array $methods, array $exclude_guids_for_records = []) {

        if (empty($methods)) {
            return [];
        }

        $object = $event->getObject();
        if (!$object instanceof \ElggData) {
            return [];
        }

        // get subscribers only for \ElggEntity if it isn't private
        if (!$object instanceof \ElggEntity || $object->access_id === ACCESS_PRIVATE) {
            return [];
        }

        $guids = [
            $object->owner_guid,
            $object->container_guid,
        ];
        if ($object instanceof \ElggObject || $object instanceof \ElggGroup) {
            $guids[] = $object->guid;
        }
        
        $guids = array_diff($guids, $exclude_guids_for_records);
        if (empty($guids)) {
            return [];
        }
        
        $subscriptions = [];
        $records = $this->getSubscriptionRecords($guids, $methods, $object->type, $object->subtype, $event->getAction(), $event->getActorGUID());
        foreach ($records as $record) {
            if (empty($record->guid)) {
                // happens when no records are found
                continue;
            }
            
            if (!isset($subscriptions[$record->guid])) {
                $subscriptions[$record->guid] = [];
            }
            
            $deliveryMethods = explode(',', $record->methods);
            foreach ($deliveryMethods as $relationship) {
                $relationship_array = explode(':', $relationship);
                
                $subscriptions[$record->guid][] = end($relationship_array);
            }
        }

        return $subscriptions;
    }

    public function getSubscriptionsForContainer(int $container_guid, array $methods, string $type = null, string $subtype = null, string $action = null, int $actor_guid = 0) {

        if (empty($methods)) {
            return [];
        }

        $subscriptions = [];

        $records = $this->getSubscriptionRecords([$container_guid], $methods, $type, $subtype, $action, $actor_guid);
        foreach ($records as $record) {
            if (empty($record->guid)) {
                // happens when no records are found
                continue;
            }
            
            if (!isset($subscriptions[$record->guid])) {
                $subscriptions[$record->guid] = [];
            }
            
            $deliveryMethods = explode(',', $record->methods);
            foreach ($deliveryMethods as $relationship) {
                $relationship_array = explode(':', $relationship);
                
                $subscriptions[$record->guid][] = end($relationship_array);
            }
        }

        return $subscriptions;
    }

    public function addSubscription(int $user_guid, string $method, int $target_guid, string $type = null, string $subtype = null, string $action = null) {
        $this->assertValidTypeSubtypeActionForSubscription($type, $subtype, $action);
        
        $rel = [
            self::RELATIONSHIP_PREFIX,
        ];
        
        if (!_elgg_services()->notifications->isRegisteredMethod($method)) {
            return false;
        }
        
        // remove the muted notification relationship
        $this->unmuteNotifications($user_guid, $target_guid);
        
        if (!empty($type) && !empty($subtype) && !empty($action)) {
            $rel[] = $type;
            $rel[] = $subtype;
            $rel[] = $action;
        }
        
        $rel[] = $method;
        
        return $this->relationshipsTable->add($user_guid, implode(':', $rel), $target_guid);
    }
    
    public function hasSubscription(int $user_guid, string $method, int $target_guid, string $type = null, string $subtype = null, string $action = null): bool {
        $this->assertValidTypeSubtypeActionForSubscription($type, $subtype, $action);
        
        $rel = [
            self::RELATIONSHIP_PREFIX,
        ];
        
        if (!empty($type) && !empty($subtype) && !empty($action)) {
            $rel[] = $type;
            $rel[] = $subtype;
            $rel[] = $action;
        }
        
        $rel[] = $method;
        
        return $this->relationshipsTable->check($user_guid, implode(':', $rel), $target_guid) instanceof \ElggRelationship;
    }
    
    public function hasSubscriptions(int $user_guid, int $target_guid, array $methods = []): bool {
        if (empty($methods)) {
            // all currently registered methods
            $methods = _elgg_services()->notifications->getMethods();
        }
        
        if (empty($methods)) {
            // no methods available
            return false;
        }
        
        $select = Select::fromTable('entity_relationships');
        $select->select('count(*) as total')
            ->where($select->compare('guid_one', '=', $user_guid, ELGG_VALUE_GUID))
            ->andWhere($select->compare('guid_two', '=', $target_guid, ELGG_VALUE_GUID));
        
        $ors = [];
        foreach ($methods as $method) {
            $ors[] = $select->compare('relationship', '=', self::RELATIONSHIP_PREFIX . ':' . $method, ELGG_VALUE_STRING);
            $ors[] = $select->compare('relationship', 'like', self::RELATIONSHIP_PREFIX . ':%:' . $method, ELGG_VALUE_STRING);
        }
        
        $select->andWhere($select->merge($ors, 'OR'));
        
        $result = $this->db->getDataRow($select);
        
        return (bool) $result->total;
    }

    public function removeSubscription(int $user_guid, string $method, int $target_guid, string $type = null, string $subtype = null, string $action = null) {
        $this->assertValidTypeSubtypeActionForSubscription($type, $subtype, $action);
        
        $rel = [
            self::RELATIONSHIP_PREFIX,
        ];
        
        if (!empty($type) && !empty($subtype) && !empty($action)) {
            $rel[] = $type;
            $rel[] = $subtype;
            $rel[] = $action;
        }
        
        $rel[] = $method;
        
        if (!$this->relationshipsTable->check($user_guid, implode(':', $rel), $target_guid)) {
            // subscription doesn't exist
            return true;
        }
        
        return $this->relationshipsTable->remove($user_guid, implode(':', $rel), $target_guid);
    }
    
    public function removeSubscriptions(int $user_guid, int $target_guid, array $methods = []): bool {
        $delete = Delete::fromTable('entity_relationships');
        $delete->where($delete->compare('guid_one', '=', $user_guid, ELGG_VALUE_GUID))
            ->andWhere($delete->compare('guid_two', '=', $target_guid, ELGG_VALUE_GUID));
        
        if (empty($methods)) {
            $delete->andWhere($delete->compare('relationship', 'like', self::RELATIONSHIP_PREFIX . ':%', ELGG_VALUE_STRING));
        } else {
            $ors = [];
            foreach ($methods as $method) {
                $ors[] = $delete->compare('relationship', '=', self::RELATIONSHIP_PREFIX . ':' . $method, ELGG_VALUE_STRING);
                $ors[] = $delete->compare('relationship', 'like', self::RELATIONSHIP_PREFIX . ':%:' . $method, ELGG_VALUE_STRING);
            }
            
            $delete->andWhere($delete->merge($ors, 'OR'));
        }
        
        return (bool) $this->db->deleteData($delete);
    }
    
    public function getSubscribers(int $target_guid, array $methods = []): array {
        return elgg_get_entities([
            'limit' => false,
            'wheres' => [
                function(QueryBuilder $qb, $main_alias) use ($target_guid) {
                    $rel = $qb->joinRelationshipTable($main_alias, 'guid', null, true);
                    
                    return $qb->compare("{$rel}.guid_two", '=', $target_guid, ELGG_VALUE_GUID);
                },
                function(QueryBuilder $qb, $main_alias) use ($methods) {
                    $rel = $qb->joinRelationshipTable($main_alias, 'guid', null, true);
                    
                    if (empty($methods)) {
                        return $qb->compare("{$rel}.relationship", 'like', self::RELATIONSHIP_PREFIX . ':%', ELGG_VALUE_STRING);
                    }
                    
                    $ors = [];
                    foreach ($methods as $method) {
                        $ors[] = $qb->compare("{$rel}.relationship", '=', self::RELATIONSHIP_PREFIX . ':' . $method, ELGG_VALUE_STRING);
                        $ors[] = $qb->compare("{$rel}.relationship", 'like', self::RELATIONSHIP_PREFIX . ':%:' . $method, ELGG_VALUE_STRING);
                    }
                    
                    return $qb->merge($ors, 'OR');
                },
            ],
        ]);
    }
    
    public function getEntitySubscriptions(int $target_guid = 0, int $user_guid = 0, array $methods = [], string $type = null, string $subtype = null, string $action = null): array {
        $this->assertValidTypeSubtypeActionForSubscription($type, $subtype, $action);
        
        if (empty($target_guid) && empty($user_guid)) {
            return [];
        }
        
        if (empty($target_guid)) {
            $target_guid = ELGG_ENTITIES_ANY_VALUE;
        }
        
        return elgg_get_relationships([
            'limit' => false,
            'wheres' => [
                function(QueryBuilder $qb, $main_alias) use ($target_guid) {
                    if (empty($target_guid)) {
                        return;
                    }
                    
                    return $qb->compare("{$main_alias}.guid_two", '=', $target_guid, ELGG_VALUE_GUID);
                },
                function(QueryBuilder $qb, $main_alias) use ($user_guid) {
                    if (empty($user_guid)) {
                        return;
                    }
                    
                    return $qb->compare("{$main_alias}.guid_one", '=', $user_guid, ELGG_VALUE_GUID);
                },
                function(QueryBuilder $qb, $main_alias) use ($methods, $type, $subtype, $action) {
                    if (empty($methods) && (empty($type) || empty($subtype) || empty($action))) {
                        return $qb->compare("{$main_alias}.relationship", 'like', self::RELATIONSHIP_PREFIX . ':%', ELGG_VALUE_STRING);
                    }
                    
                    if (!empty($methods)) {
                        if (empty($type) || empty($subtype) || empty($action)) {
                            // only methods
                            $ors = [];
                            foreach ($methods as $method) {
                                $ors[] = $qb->compare("{$main_alias}.relationship", '=', self::RELATIONSHIP_PREFIX . ':' . $method, ELGG_VALUE_STRING);
                                $ors[] = $qb->compare("{$main_alias}.relationship", 'like', self::RELATIONSHIP_PREFIX . ':%:' . $method, ELGG_VALUE_STRING);
                            }
                            
                            return $qb->merge($ors, 'OR');
                        } else {
                            // with type limitation
                            return $qb->compare("{$main_alias}.relationship", 'in', $this->getMethodRelationships($methods, $type, $subtype, $action), ELGG_VALUE_STRING);
                        }
                    }
                    
                    // only type limitation
                    return $qb->compare("{$main_alias}.relationship", 'like', self::RELATIONSHIP_PREFIX . ":{$type}:{$subtype}:{$action}:%", ELGG_VALUE_STRING);
                },
            ],
        ]);
    }
    
    public function muteNotifications(int $user_guid, int $target_guid): bool {
        // remove all current subscriptions
        $this->removeSubscriptions($user_guid, $target_guid);
        
        return $this->relationshipsTable->add($user_guid, self::MUTE_NOTIFICATIONS_RELATIONSHIP, $target_guid);
    }
    
    public function unmuteNotifications(int $user_guid, int $target_guid): bool {
        return $this->relationshipsTable->remove($user_guid, self::MUTE_NOTIFICATIONS_RELATIONSHIP, $target_guid);
    }
    
    public function hasMutedNotifications(int $user_guid, int $target_guid): bool {
        return $this->relationshipsTable->check($user_guid, self::MUTE_NOTIFICATIONS_RELATIONSHIP, $target_guid) instanceof \ElggRelationship;
    }
    
    public function filterSubscriptions(array $subscriptions, NotificationEvent $event, bool $filter_muted = true): array {
        // sanitize
        // make methods unique and remove empties
        $subscriptions = array_map(function($user_methods) {
            return array_values(array_filter(array_unique($user_methods)));
        }, $subscriptions);
        $subscriptions = $this->filterDelayedEmailSubscribers($subscriptions);
        
        // apply filters
        if ($filter_muted) {
            $subscriptions = $this->filterMutedNotifications($subscriptions, $event);
            $subscriptions = $this->filterTimedMutedSubscribers($subscriptions);
        }
        
        return $subscriptions;
    }
    
    protected function filterMutedNotifications(array $subscriptions, NotificationEvent $event): array {
        $guids_to_check = [];
        
        // Event actor
        $guids_to_check[] = $event->getActorGUID();
        
        // Event object
        $entity = false;
        $object = $event->getObject();
        if ($object instanceof \ElggEntity) {
            $entity = $object;
        } elseif ($object instanceof \ElggAnnotation) {
            $entity = $object->getEntity();
        }
        
        if ($entity instanceof \ElggEntity) {
            $guids_to_check[] = $entity->guid;
            $guids_to_check[] = $entity->owner_guid;
            $guids_to_check[] = $entity->container_guid;
        }
        
        // are there GUIDs to check
        $guids_to_check = array_filter($guids_to_check);
        if (empty($guids_to_check)) {
            return $subscriptions;
        }
        
        // get muted relations
        $select = Select::fromTable('entity_relationships');
        $select->select('guid_one')
            ->where($select->compare('relationship', '=', self::MUTE_NOTIFICATIONS_RELATIONSHIP, ELGG_VALUE_STRING))
            ->andWhere($select->compare('guid_two', 'in', $guids_to_check, ELGG_VALUE_GUID));
        
        $muted = $this->db->getData($select, function($row) {
            return (int) $row->guid_one;
        });
        
        // filter subscriptions
        return array_diff_key($subscriptions, array_flip($muted));
    }
    
    protected function filterDelayedEmailSubscribers(array $subscriptions): array {
        return array_map(function ($user_methods) {
            if (!in_array('delayed_email', $user_methods) || !in_array('email', $user_methods)) {
                return $user_methods;
            }
            
            $pos = array_search('delayed_email', $user_methods);
            unset($user_methods[$pos]);
            
            return array_values($user_methods);
        }, $subscriptions);
    }
    
    protected function filterTimedMutedSubscribers(array $subscriptions): array {
        $muted = Entities::find([
            'type' => 'user',
            'guids' => array_keys($subscriptions),
            'limit' => false,
            'callback' => function ($row) {
                return (int) $row->guid;
            },
            'metadata_name_value_pairs' => [
                [
                    'name' => 'timed_muting_start',
                    'value' => time(),
                    'operand' => '<=',
                ],
                [
                    'name' => 'timed_muting_end',
                    'value' => time(),
                    'operand' => '>=',
                ],
            ],
        ]);
        
        return array_diff_key($subscriptions, array_flip($muted));
    }

    protected function getSubscriptionRecords(array $container_guid, array $methods, string $type = null, string $subtype = null, string $action = null, int $actor_guid = 0): array {
        // create IN clause
        $rels = $this->getMethodRelationships($methods, $type, $subtype, $action);
        if (!$rels) {
            return [];
        }
        
        $container_guid = array_unique(array_filter($container_guid));
        if (empty($container_guid)) {
            return [];
        }

        $select = Select::fromTable('entity_relationships');
        $select->select('guid_one AS guid')
            ->addSelect("GROUP_CONCAT(relationship SEPARATOR ',') AS methods")
            ->where($select->compare('guid_two', 'in', $container_guid, ELGG_VALUE_GUID))
            ->andWhere($select->compare('relationship', 'in', $rels, ELGG_VALUE_STRING))
            ->groupBy('guid_one');
        
        if (!empty($actor_guid)) {
            $select->andWhere($select->compare('guid_one', '!=', $actor_guid, ELGG_VALUE_GUID));
        }
        
        return $this->db->getData($select);
    }

    protected function getMethodRelationships(array $methods, string $type = null, string $subtype = null, string $action = null): array {
        $prefix = self::RELATIONSHIP_PREFIX;
        
        $names = [];
        foreach ($methods as $method) {
            $names[] = "{$prefix}:{$method}";
            
            if (!empty($type) && !empty($subtype) && !empty($action)) {
                $names[] = "{$prefix}:{$type}:{$subtype}:{$action}:{$method}";
            }
        }
        
        return $names;
    }
    
    protected function assertValidTypeSubtypeActionForSubscription($type, $subtype, $action): void {
        if (empty($type) && empty($subtype) && empty($action)) {
            // all empty, this is valid
            return;
        }
        
        if (!empty($type) && !empty($subtype) && !empty($action)) {
            // all set, also valid
            return;
        }
        
        throw new InvalidArgumentException('$type, $subtype and $action need to all be empty or all have a value');
    }
}