myLastRead.swift

// Gather unread messages since the last date.
var unreads = models.filter { message in
    return message.model.createdDate?.isAfterDate(date, granularity: .second) ?? false
}

// Among unread messages, drops those sent by me since they are known by the current user.
unreads = Array(unreads.drop(while: { message in
    return message.model.isMe
}))

// If unread message is found, scroll to that message.
if let firstUnread = unreads.first, let indexPath = list.indexPath(of: firstUnread) {
    self.scrollToRow(at: indexPath, at: .top, animated: false)
// If none, scroll to last one.
} else if let last = indexPathes.last {
    self.scrollToRow(at: last, at: .top, animated: false)
}