import UIKit

class LeftAlignedCollectionViewFlowLayout: UICollectionViewFlowLayout {

    override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
        guard let superArray = super.layoutAttributesForElements(in: rect),
            let attributes = NSArray(array: superArray, copyItems: true) as? [UICollectionViewLayoutAttributes] else { return nil }

        var leftMargin = sectionInset.left
        var maxY: CGFloat = -1.0
        attributes.forEach { layoutAttribute in
            guard layoutAttribute.representedElementCategory == .cell else {
                return
            }
            guard layoutAttribute.indexPath.section == 0 else {
                return
            }
            if layoutAttribute.frame.origin.y >= maxY {
                leftMargin = sectionInset.left
            }

            layoutAttribute.frame.origin.x = leftMargin

            leftMargin += layoutAttribute.frame.width + ((self.collectionView?.delegate as? UICollectionViewDelegateFlowLayout)?.collectionView?(self.collectionView!, layout: self, minimumInteritemSpacingForSectionAt: 0) ?? 0 )
            maxY = max(layoutAttribute.frame.maxY , maxY)
        }

        return attributes
    }


}