UICollectionViewExtension.swift

extension UICollectionView {

    func indexPathsForCloseItems(offset: Int) -> [IndexPath] {
        var indexes = indexPathsForVisibleItems.sorted(by: { $0.row < $1.row })

        for x in indexes {
            print("had: \(x)")
        }

        if let index = indexes.last {
            for ix in ((index.row + 1)...(index.row + 11)) {
                let x = createIndexPath(row: ix, section: index.section)
                indexes.append(x)
                print("adding: \(x)")
            }
        }

        if let index = indexes.first {
            for ix in ((index.row - 11)...(index.row - 1)) {
                let x = createIndexPath(row: ix, section: index.section)
                indexes.append(x)
                print("adding: \(x)")
            }
        }
        return indexes
    }

    func createIndexPath(row: Int, section: Int) -> IndexPath {
        let totalRows = numberOfItems(inSection: section)
        if row > totalRows {
            return createIndexPath(row: row - totalRows, section: section + 1)
        }
        if row < 0 {
            let prevSectionRows = numberOfItems(inSection: section - 1)
            return createIndexPath(row: prevSectionRows - abs(row), section: section - 1)
        }
        return IndexPath(item: row, section: section)
    }
}