import UIKit

class CustomFlowLayout: UICollectionViewFlowLayout {

    override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
        guard let collectionView = collectionView else { return nil }

        // Retrieve the layout attributes from the super class
        var layoutAttributes = super.layoutAttributesForElements(in: rect)

        // Check if refresh control is refreshing and adjust header position if needed
        if let refreshControl = collectionView.refreshControl, refreshControl.isRefreshing {
            for attributes in layoutAttributes ?? [] {
                // Adjust header attributes if the element is a section header
                if attributes.representedElementKind == UICollectionView.elementKindSectionHeader {
                    let section = attributes.indexPath.section
                    let headerHeight = headerReferenceSize.height
                    let contentOffset = collectionView.contentOffset.y + collectionView.contentInset.top
                    let topInset = collectionView.adjustedContentInset.top

                    // Calculate the y position of the header
                    var headerY = max(contentOffset, topInset)
                    if section > 0 {
                        // Adjust header position based on previous sections' height
                        for i in 0..<section {
                            let previousHeaderHeight = headerReferenceSize.height
                            let previousSectionItemCount = collectionView.numberOfItems(inSection: i)
                            let previousSectionHeight = (CGFloat(previousSectionItemCount) * itemSize.height) + previousHeaderHeight + minimumLineSpacing
                            headerY += previousSectionHeight
                        }
                    }

                    // Update the position of the header attributes
                    attributes.frame = CGRect(x: attributes.frame.origin.x, y: headerY, width: attributes.frame.width, height: headerHeight)
                }
            }
        }

        return layoutAttributes
    }

    override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
        return true
    }
}