TaskEditRule::execute

public function execute(AccessibleItem $task = null, $params = null): bool
{
	if (!$task)
	{
		$this->controller->addError(static::class, 'Incorrect task');
		return false;
	}

	if ($this->user->isAdmin())
	{
		return true;
	}

	if (
		$task->getGroupId()
		&& Loader::includeModule("socialnetwork")
		&& BitrixSocialnetworkInternalsRegistryFeaturePermRegistry::getInstance()->get(
			$task->getGroupId(),
			'tasks',
			'edit_tasks',
			$this->user->getUserId()
		)
	)
	{
		return true;
	}

	if (
		!$task->isClosed()
		&& $task->isMember($this->user->getUserId(), RoleDictionary::ROLE_DIRECTOR)
	)
	{
		return true;
	}

	if (
		$task->isClosed()
		&& $task->isMember($this->user->getUserId(), RoleDictionary::ROLE_DIRECTOR)
		&& $this->user->getPermission(PermissionDictionary::TASK_CLOSED_DIRECTOR_EDIT)
	)
	{
		return true;
	}

	if (
		$task->isMember($this->user->getUserId(), RoleDictionary::ROLE_RESPONSIBLE)
		&& $this->user->getPermission(PermissionDictionary::TASK_RESPONSE_EDIT)
		&& !$task->isClosed()
	)
	{
		return true;
	}

	// can edit subordinate's task
	if (
		array_intersect($task->getMembers(RoleDictionary::ROLE_DIRECTOR), $this->user->getAllSubordinates())
	)
	{
		return true;
	}

	$isInDepartment = $task->isInDepartment($this->user->getUserId(), false, [RoleDictionary::ROLE_RESPONSIBLE, RoleDictionary::ROLE_DIRECTOR, RoleDictionary::ROLE_ACCOMPLICE]);

	if (
		$this->user->getPermission(PermissionDictionary::TASK_DEPARTMENT_EDIT)
		&& $isInDepartment
		&& !$task->isClosed()
	)
	{
		return true;
	}

	if (
		$this->user->getPermission(PermissionDictionary::TASK_CLOSED_DEPARTMENT_EDIT)
		&& $isInDepartment
		&& $task->isClosed()
	)
	{
		return true;
	}

	if (
		$this->user->getPermission(PermissionDictionary::TASK_NON_DEPARTMENT_EDIT)
		&& !$isInDepartment
		&& !$task->isClosed()
	)
	{
		return true;
	}

	if (
		$this->user->getPermission(PermissionDictionary::TASK_CLOSED_NON_DEPARTMENT_EDIT)
		&& !$isInDepartment
		&& $task->isClosed()
	)
	{
		return true;
	}

	$this->controller->addError(static::class, 'Access to edit task denied');
	return false;
}