nextcloud / server

apps/systemtags/lib/Activity/Provider.php

Indentation +335 added lines, -335 removed lines

@@ -34,339 +34,339 @@
 
 class Provider implements IProvider {
 
-	const CREATE_TAG = 'create_tag';
-	const UPDATE_TAG = 'update_tag';
-	const DELETE_TAG = 'delete_tag';
-
-	const ASSIGN_TAG = 'assign_tag';
-	const UNASSIGN_TAG = 'unassign_tag';
-
-	/** @var IFactory */
-	protected $languageFactory;
-
-	/** @var IL10N */
-	protected $l;
-
-	/** @var IURLGenerator */
-	protected $url;
-
-	/** @var IManager */
-	protected $activityManager;
-
-	/** @var IUserManager */
-	protected $userManager;
-
-	/** @var string[] */
-	protected $displayNames = [];
-
-	/**
-	 * @param IFactory $languageFactory
-	 * @param IURLGenerator $url
-	 * @param IManager $activityManager
-	 * @param IUserManager $userManager
-	 */
-	public function __construct(IFactory $languageFactory, IURLGenerator $url, IManager $activityManager, IUserManager $userManager) {
-		$this->languageFactory = $languageFactory;
-		$this->url = $url;
-		$this->activityManager = $activityManager;
-		$this->userManager = $userManager;
-	}
-
-	/**
-	 * @param string $language
-	 * @param IEvent $event
-	 * @param IEvent|null $previousEvent
-	 * @return IEvent
-	 * @throws \InvalidArgumentException
-	 * @since 11.0.0
-	 */
-	public function parse($language, IEvent $event, IEvent $previousEvent = null) {
-		if ($event->getApp() !== 'systemtags') {
-			throw new \InvalidArgumentException();
-		}
-
-		$this->l = $this->languageFactory->get('systemtags', $language);
-
-		if ($this->activityManager->isFormattingFilteredObject()) {
-			try {
-				return $this->parseShortVersion($event);
-			} catch (\InvalidArgumentException $e) {
-				// Ignore and simply use the long version...
-			}
-		}
-
-		return $this->parseLongVersion($event);
-	}
-
-	/**
-	 * @param IEvent $event
-	 * @return IEvent
-	 * @throws \InvalidArgumentException
-	 * @since 11.0.0
-	 */
-	public function parseShortVersion(IEvent $event) {
-		$parsedParameters = $this->getParameters($event);
-
-		if ($this->activityManager->getRequirePNG()) {
-			$event->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'actions/tag.png')));
-		} else {
-			$event->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'actions/tag.svg')));
-		}
-
-		if ($event->getSubject() === self::ASSIGN_TAG) {
-			if ($parsedParameters['actor']['id'] === '') {
-				$event->setParsedSubject($this->l->t('System tag %1$s added by the system', [
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('Added system tag {systemtag}'), [
-						'systemtag' => $parsedParameters['systemtag'],
-					]);
-			} else if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
-				$event->setParsedSubject($this->l->t('Added system tag %1$s', [
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('Added system tag {systemtag}'), [
-						'systemtag' => $parsedParameters['systemtag'],
-					]);
-			} else {
-				$event->setParsedSubject($this->l->t('%1$s added system tag %2$s', [
-						$parsedParameters['actor']['name'],
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('{actor} added system tag {systemtag}'), [
-						'actor' => $parsedParameters['actor'],
-						'systemtag' => $parsedParameters['systemtag'],
-					]);
-			}
-		} else if ($event->getSubject() === self::UNASSIGN_TAG) {
-			if ($parsedParameters['actor']['id'] === '') {
-				$event->setParsedSubject($this->l->t('System tag %1$s removed by the system', [
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('Removed system tag {systemtag}'), [
-						'systemtag' => $parsedParameters['systemtag'],
-					]);
-			} else if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
-				$event->setParsedSubject($this->l->t('Removed system tag %1$s', [
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('Removed system tag {systemtag}'), [
-						'systemtag' => $parsedParameters['systemtag'],
-					]);
-			} else {
-				$event->setParsedSubject($this->l->t('%1$s removed system tag %2$s', [
-						$parsedParameters['actor']['name'],
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('{actor} removed system tag {systemtag}'), [
-						'actor' => $parsedParameters['actor'],
-						'systemtag' => $parsedParameters['systemtag'],
-					]);
-			}
-		} else {
-			throw new \InvalidArgumentException();
-		}
-
-		return $event;
-	}
-
-	/**
-	 * @param IEvent $event
-	 * @return IEvent
-	 * @throws \InvalidArgumentException
-	 * @since 11.0.0
-	 */
-	public function parseLongVersion(IEvent $event) {
-		$parsedParameters = $this->getParameters($event);
-
-		if ($this->activityManager->getRequirePNG()) {
-			$event->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'actions/tag.png')));
-		} else {
-			$event->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'actions/tag.svg')));
-		}
-
-		if ($event->getSubject() === self::CREATE_TAG) {
-			if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
-				$event->setParsedSubject($this->l->t('You created system tag %1$s', [
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('You created system tag {systemtag}'), $parsedParameters);
-			} else {
-				$event->setParsedSubject($this->l->t('%1$s created system tag %2$s', [
-						$parsedParameters['actor']['name'],
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('{actor} created system tag {systemtag}'), $parsedParameters);
-			}
-		} else if ($event->getSubject() === self::DELETE_TAG) {
-			if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
-				$event->setParsedSubject($this->l->t('You deleted system tag %1$s', [
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('You deleted system tag {systemtag}'), $parsedParameters);
-			} else {
-				$event->setParsedSubject($this->l->t('%1$s deleted system tag %2$s', [
-						$parsedParameters['actor']['name'],
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('{actor} deleted system tag {systemtag}'), $parsedParameters);
-			}
-		} else if ($event->getSubject() === self::UPDATE_TAG) {
-			if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
-				$event->setParsedSubject($this->l->t('You updated system tag %2$s to %1$s', [
-						$this->generatePlainSystemTag($parsedParameters['newsystemtag']),
-						$this->generatePlainSystemTag($parsedParameters['oldsystemtag']),
-					]))
-					->setRichSubject($this->l->t('You updated system tag {oldsystemtag} to {newsystemtag}'), $parsedParameters);
-			} else {
-				$event->setParsedSubject($this->l->t('%1$s updated system tag %3$s to %2$s', [
-						$parsedParameters['actor']['name'],
-						$this->generatePlainSystemTag($parsedParameters['newsystemtag']),
-						$this->generatePlainSystemTag($parsedParameters['oldsystemtag']),
-					]))
-					->setRichSubject($this->l->t('{actor} updated system tag {oldsystemtag} to {newsystemtag}'), $parsedParameters);
-			}
-		} else if ($event->getSubject() === self::ASSIGN_TAG) {
-			if ($parsedParameters['actor']['id'] === '') {
-				unset($parsedParameters['actor']);
-				$event->setParsedSubject($this->l->t('System tag %2$s was added to %1$s by the system', [
-						$parsedParameters['file']['path'],
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('System tag {systemtag} was added to {file} by the system'), $parsedParameters);
-			} else if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
-				$event->setParsedSubject($this->l->t('You added system tag %2$s to %1$s', [
-						$parsedParameters['file']['path'],
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('You added system tag {systemtag} to {file}'), $parsedParameters);
-			} else {
-				$event->setParsedSubject($this->l->t('%1$s added system tag %3$s to %2$s', [
-						$parsedParameters['actor']['name'],
-						$parsedParameters['file']['path'],
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('{actor} added system tag {systemtag} to {file}'), $parsedParameters);
-			}
-		} else if ($event->getSubject() === self::UNASSIGN_TAG) {
-			if ($parsedParameters['actor']['id'] === '') {
-				unset($parsedParameters['actor']);
-				$event->setParsedSubject($this->l->t('System tag %2$s was removed from %1$s by the system', [
-						$parsedParameters['file']['path'],
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('System tag {systemtag} was removed from {file} by the system'), $parsedParameters);
-			} else if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
-				$event->setParsedSubject($this->l->t('You removed system tag %2$s from %1$s', [
-						$parsedParameters['file']['path'],
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('You removed system tag {systemtag} from {file}'), $parsedParameters);
-			} else {
-				$event->setParsedSubject($this->l->t('%1$s removed system tag %3$s from %2$s', [
-						$parsedParameters['actor']['name'],
-						$parsedParameters['file']['path'],
-						$this->generatePlainSystemTag($parsedParameters['systemtag']),
-					]))
-					->setRichSubject($this->l->t('{actor} removed system tag {systemtag} from {file}'), $parsedParameters);
-			}
-		} else {
-			throw new \InvalidArgumentException();
-		}
-
-		return $event;
-	}
-
-	protected function getParameters(IEvent $event) {
-		$subject = $event->getSubject();
-		$parameters = $event->getSubjectParameters();
-
-		switch ($subject) {
-			case self::CREATE_TAG:
-			case self::DELETE_TAG:
-				return [
-					'actor' => $this->getUserParameter((string) $parameters[0]),
-					'systemtag' => $this->getSystemTagParameter($parameters[1]),
-				];
-			case self::UPDATE_TAG:
-				return [
-					'actor' => $this->getUserParameter((string) $parameters[0]),
-					'newsystemtag' => $this->getSystemTagParameter($parameters[1]),
-					'oldsystemtag' => $this->getSystemTagParameter($parameters[2]),
-				];
-			case self::ASSIGN_TAG:
-			case self::UNASSIGN_TAG:
-				return [
-					'actor' => $this->getUserParameter((string) $parameters[0]),
-					'file' => $this->getFileParameter($event->getObjectId(), $parameters[1]),
-					'systemtag' => $this->getSystemTagParameter($parameters[2]),
-				];
-		}
-		return [];
-	}
-
-	protected function getFileParameter($id, $path) {
-		return [
-			'type' => 'file',
-			'id' => $id,
-			'name' => basename($path),
-			'path' => trim($path, '/'),
-		];
-	}
-
-	protected function getSystemTagParameter($parameter) {
-		$tagData = json_decode($parameter, true);
-		if ($tagData === null) {
-			list($name, $status) = explode('|||', substr($parameter, 3, -3));
-			$tagData = [
-				'id' => 0,// No way to recover the ID
-				'name' => $name,
-				'assignable' => $status === 'assignable',
-				'visible' => $status !== 'invisible',
-			];
-		}
-
-		return [
-			'type' => 'systemtag',
-			'id' => (int) $tagData['id'],
-			'name' => $tagData['name'],
-			'assignable' => $tagData['assignable'] ? '1' : '0',
-			'visibility' => $tagData['visible'] ? '1' : '0',
-		];
-	}
-
-	protected function getUserParameter($uid) {
-		if (!isset($this->displayNames[$uid])) {
-			$this->displayNames[$uid] = $this->getDisplayName($uid);
-		}
-
-		return [
-			'type' => 'user',
-			'id' => $uid,
-			'name' => $this->displayNames[$uid],
-		];
-	}
-
-	protected function generatePlainSystemTag(array $parameter) {
-		if ($parameter['assignable'] === '1') {
-			return $parameter['name'];
-		} else if ($parameter['visibility'] === '1') {
-			return $this->l->t('%s (restricted)', $parameter['name']);
-		} else {
-			return $this->l->t('%s (invisible)', $parameter['name']);
-		}
-	}
-
-	/**
-	 * @param string $uid
-	 * @return string
-	 */
-	protected function getDisplayName($uid) {
-		$user = $this->userManager->get($uid);
-		if ($user instanceof IUser) {
-			return $user->getDisplayName();
-		} else {
-			return $uid;
-		}
-	}
+    const CREATE_TAG = 'create_tag';
+    const UPDATE_TAG = 'update_tag';
+    const DELETE_TAG = 'delete_tag';
+
+    const ASSIGN_TAG = 'assign_tag';
+    const UNASSIGN_TAG = 'unassign_tag';
+
+    /** @var IFactory */
+    protected $languageFactory;
+
+    /** @var IL10N */
+    protected $l;
+
+    /** @var IURLGenerator */
+    protected $url;
+
+    /** @var IManager */
+    protected $activityManager;
+
+    /** @var IUserManager */
+    protected $userManager;
+
+    /** @var string[] */
+    protected $displayNames = [];
+
+    /**
+     * @param IFactory $languageFactory
+     * @param IURLGenerator $url
+     * @param IManager $activityManager
+     * @param IUserManager $userManager
+     */
+    public function __construct(IFactory $languageFactory, IURLGenerator $url, IManager $activityManager, IUserManager $userManager) {
+        $this->languageFactory = $languageFactory;
+        $this->url = $url;
+        $this->activityManager = $activityManager;
+        $this->userManager = $userManager;
+    }
+
+    /**
+     * @param string $language
+     * @param IEvent $event
+     * @param IEvent|null $previousEvent
+     * @return IEvent
+     * @throws \InvalidArgumentException
+     * @since 11.0.0
+     */
+    public function parse($language, IEvent $event, IEvent $previousEvent = null) {
+        if ($event->getApp() !== 'systemtags') {
+            throw new \InvalidArgumentException();
+        }
+
+        $this->l = $this->languageFactory->get('systemtags', $language);
+
+        if ($this->activityManager->isFormattingFilteredObject()) {
+            try {
+                return $this->parseShortVersion($event);
+            } catch (\InvalidArgumentException $e) {
+                // Ignore and simply use the long version...
+            }
+        }
+
+        return $this->parseLongVersion($event);
+    }
+
+    /**
+     * @param IEvent $event
+     * @return IEvent
+     * @throws \InvalidArgumentException
+     * @since 11.0.0
+     */
+    public function parseShortVersion(IEvent $event) {
+        $parsedParameters = $this->getParameters($event);
+
+        if ($this->activityManager->getRequirePNG()) {
+            $event->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'actions/tag.png')));
+        } else {
+            $event->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'actions/tag.svg')));
+        }
+
+        if ($event->getSubject() === self::ASSIGN_TAG) {
+            if ($parsedParameters['actor']['id'] === '') {
+                $event->setParsedSubject($this->l->t('System tag %1$s added by the system', [
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('Added system tag {systemtag}'), [
+                        'systemtag' => $parsedParameters['systemtag'],
+                    ]);
+            } else if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
+                $event->setParsedSubject($this->l->t('Added system tag %1$s', [
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('Added system tag {systemtag}'), [
+                        'systemtag' => $parsedParameters['systemtag'],
+                    ]);
+            } else {
+                $event->setParsedSubject($this->l->t('%1$s added system tag %2$s', [
+                        $parsedParameters['actor']['name'],
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('{actor} added system tag {systemtag}'), [
+                        'actor' => $parsedParameters['actor'],
+                        'systemtag' => $parsedParameters['systemtag'],
+                    ]);
+            }
+        } else if ($event->getSubject() === self::UNASSIGN_TAG) {
+            if ($parsedParameters['actor']['id'] === '') {
+                $event->setParsedSubject($this->l->t('System tag %1$s removed by the system', [
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('Removed system tag {systemtag}'), [
+                        'systemtag' => $parsedParameters['systemtag'],
+                    ]);
+            } else if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
+                $event->setParsedSubject($this->l->t('Removed system tag %1$s', [
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('Removed system tag {systemtag}'), [
+                        'systemtag' => $parsedParameters['systemtag'],
+                    ]);
+            } else {
+                $event->setParsedSubject($this->l->t('%1$s removed system tag %2$s', [
+                        $parsedParameters['actor']['name'],
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('{actor} removed system tag {systemtag}'), [
+                        'actor' => $parsedParameters['actor'],
+                        'systemtag' => $parsedParameters['systemtag'],
+                    ]);
+            }
+        } else {
+            throw new \InvalidArgumentException();
+        }
+
+        return $event;
+    }
+
+    /**
+     * @param IEvent $event
+     * @return IEvent
+     * @throws \InvalidArgumentException
+     * @since 11.0.0
+     */
+    public function parseLongVersion(IEvent $event) {
+        $parsedParameters = $this->getParameters($event);
+
+        if ($this->activityManager->getRequirePNG()) {
+            $event->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'actions/tag.png')));
+        } else {
+            $event->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'actions/tag.svg')));
+        }
+
+        if ($event->getSubject() === self::CREATE_TAG) {
+            if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
+                $event->setParsedSubject($this->l->t('You created system tag %1$s', [
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('You created system tag {systemtag}'), $parsedParameters);
+            } else {
+                $event->setParsedSubject($this->l->t('%1$s created system tag %2$s', [
+                        $parsedParameters['actor']['name'],
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('{actor} created system tag {systemtag}'), $parsedParameters);
+            }
+        } else if ($event->getSubject() === self::DELETE_TAG) {
+            if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
+                $event->setParsedSubject($this->l->t('You deleted system tag %1$s', [
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('You deleted system tag {systemtag}'), $parsedParameters);
+            } else {
+                $event->setParsedSubject($this->l->t('%1$s deleted system tag %2$s', [
+                        $parsedParameters['actor']['name'],
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('{actor} deleted system tag {systemtag}'), $parsedParameters);
+            }
+        } else if ($event->getSubject() === self::UPDATE_TAG) {
+            if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
+                $event->setParsedSubject($this->l->t('You updated system tag %2$s to %1$s', [
+                        $this->generatePlainSystemTag($parsedParameters['newsystemtag']),
+                        $this->generatePlainSystemTag($parsedParameters['oldsystemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('You updated system tag {oldsystemtag} to {newsystemtag}'), $parsedParameters);
+            } else {
+                $event->setParsedSubject($this->l->t('%1$s updated system tag %3$s to %2$s', [
+                        $parsedParameters['actor']['name'],
+                        $this->generatePlainSystemTag($parsedParameters['newsystemtag']),
+                        $this->generatePlainSystemTag($parsedParameters['oldsystemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('{actor} updated system tag {oldsystemtag} to {newsystemtag}'), $parsedParameters);
+            }
+        } else if ($event->getSubject() === self::ASSIGN_TAG) {
+            if ($parsedParameters['actor']['id'] === '') {
+                unset($parsedParameters['actor']);
+                $event->setParsedSubject($this->l->t('System tag %2$s was added to %1$s by the system', [
+                        $parsedParameters['file']['path'],
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('System tag {systemtag} was added to {file} by the system'), $parsedParameters);
+            } else if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
+                $event->setParsedSubject($this->l->t('You added system tag %2$s to %1$s', [
+                        $parsedParameters['file']['path'],
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('You added system tag {systemtag} to {file}'), $parsedParameters);
+            } else {
+                $event->setParsedSubject($this->l->t('%1$s added system tag %3$s to %2$s', [
+                        $parsedParameters['actor']['name'],
+                        $parsedParameters['file']['path'],
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('{actor} added system tag {systemtag} to {file}'), $parsedParameters);
+            }
+        } else if ($event->getSubject() === self::UNASSIGN_TAG) {
+            if ($parsedParameters['actor']['id'] === '') {
+                unset($parsedParameters['actor']);
+                $event->setParsedSubject($this->l->t('System tag %2$s was removed from %1$s by the system', [
+                        $parsedParameters['file']['path'],
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('System tag {systemtag} was removed from {file} by the system'), $parsedParameters);
+            } else if ($parsedParameters['actor']['id'] === $this->activityManager->getCurrentUserId()) {
+                $event->setParsedSubject($this->l->t('You removed system tag %2$s from %1$s', [
+                        $parsedParameters['file']['path'],
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('You removed system tag {systemtag} from {file}'), $parsedParameters);
+            } else {
+                $event->setParsedSubject($this->l->t('%1$s removed system tag %3$s from %2$s', [
+                        $parsedParameters['actor']['name'],
+                        $parsedParameters['file']['path'],
+                        $this->generatePlainSystemTag($parsedParameters['systemtag']),
+                    ]))
+                    ->setRichSubject($this->l->t('{actor} removed system tag {systemtag} from {file}'), $parsedParameters);
+            }
+        } else {
+            throw new \InvalidArgumentException();
+        }
+
+        return $event;
+    }
+
+    protected function getParameters(IEvent $event) {
+        $subject = $event->getSubject();
+        $parameters = $event->getSubjectParameters();
+
+        switch ($subject) {
+            case self::CREATE_TAG:
+            case self::DELETE_TAG:
+                return [
+                    'actor' => $this->getUserParameter((string) $parameters[0]),
+                    'systemtag' => $this->getSystemTagParameter($parameters[1]),
+                ];
+            case self::UPDATE_TAG:
+                return [
+                    'actor' => $this->getUserParameter((string) $parameters[0]),
+                    'newsystemtag' => $this->getSystemTagParameter($parameters[1]),
+                    'oldsystemtag' => $this->getSystemTagParameter($parameters[2]),
+                ];
+            case self::ASSIGN_TAG:
+            case self::UNASSIGN_TAG:
+                return [
+                    'actor' => $this->getUserParameter((string) $parameters[0]),
+                    'file' => $this->getFileParameter($event->getObjectId(), $parameters[1]),
+                    'systemtag' => $this->getSystemTagParameter($parameters[2]),
+                ];
+        }
+        return [];
+    }
+
+    protected function getFileParameter($id, $path) {
+        return [
+            'type' => 'file',
+            'id' => $id,
+            'name' => basename($path),
+            'path' => trim($path, '/'),
+        ];
+    }
+
+    protected function getSystemTagParameter($parameter) {
+        $tagData = json_decode($parameter, true);
+        if ($tagData === null) {
+            list($name, $status) = explode('|||', substr($parameter, 3, -3));
+            $tagData = [
+                'id' => 0,// No way to recover the ID
+                'name' => $name,
+                'assignable' => $status === 'assignable',
+                'visible' => $status !== 'invisible',
+            ];
+        }
+
+        return [
+            'type' => 'systemtag',
+            'id' => (int) $tagData['id'],
+            'name' => $tagData['name'],
+            'assignable' => $tagData['assignable'] ? '1' : '0',
+            'visibility' => $tagData['visible'] ? '1' : '0',
+        ];
+    }
+
+    protected function getUserParameter($uid) {
+        if (!isset($this->displayNames[$uid])) {
+            $this->displayNames[$uid] = $this->getDisplayName($uid);
+        }
+
+        return [
+            'type' => 'user',
+            'id' => $uid,
+            'name' => $this->displayNames[$uid],
+        ];
+    }
+
+    protected function generatePlainSystemTag(array $parameter) {
+        if ($parameter['assignable'] === '1') {
+            return $parameter['name'];
+        } else if ($parameter['visibility'] === '1') {
+            return $this->l->t('%s (restricted)', $parameter['name']);
+        } else {
+            return $this->l->t('%s (invisible)', $parameter['name']);
+        }
+    }
+
+    /**
+     * @param string $uid
+     * @return string
+     */
+    protected function getDisplayName($uid) {
+        $user = $this->userManager->get($uid);
+        if ($user instanceof IUser) {
+            return $user->getDisplayName();
+        } else {
+            return $uid;
+        }
+    }
 }