Dynamic Height for UICollectionView Cell

Question

This is my first attempt at creating a collectionView programmatically. I used a couple tutorials to get where I am now which is a Facebook/LinkedIn-esque layout with a textView and imageView. They look great when there is an image but I have no idea how to make the cell dynamically smaller in height when there is no image. I know that I currently have a fixed height of 500 but it being my first attempt, I am not sure how to set it to dynamically adjust.

I've seen a lot of Obj-C examples but nothing (that I can understand) for Swift that I know how to implement.

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {

        if let textContent = dataSource.posts[indexPath.item].textContent {
            let rect = NSString(string: textContent).boundingRectWithSize(CGSizeMake(view.frame.width, 1000), options: NSStringDrawingOptions.UsesFontLeading.union(NSStringDrawingOptions.UsesLineFragmentOrigin), attributes: [NSFontAttributeName:UIFont.systemFontOfSize(14)], context: nil)

            return CGSizeMake(view.frame.width, rect.height + 370)
        }

        return CGSizeMake(view.frame.width, 500)
    }
}

My vertical visual layout constraints (created with an extension):

 addContstraintsWithFormat("V:|-8-[v0(44)]-4-[v1]-4-[v2][v3(44)][v4(1)][v5(44)]|", views: profileImg, postTextView, postImageView, likesCommentsLabel, dividerLineView, likeButton)

Answer 1

sizeForItemAtIndexPath is one of the collection view delegate function in which you can set the height of each cell. In this delegate just add a condition.. where you can check if the cell has an image or not and based on that set the height using CGSizeMake