Getting the header to not expand until at the top of the TableView about animatingtableviewheader HOT 6 CLOSED

private func canAnimateHeader(forScrollView scrollView: UIScrollView) -> Bool {
        if scrollView.contentOffset.y >= alwaysCollapsedScrollOffset {
            return false
        }
        // isContentToScroll is same as previous implementation, 
        // I just broke it up a little
        return isContentToScroll(forScrollView: scrollView)
    }

    private func isContentToScroll(forScrollView scrollView: UIScrollView) -> Bool {
        let headerSize = headerHeight - headerHeightMinimum
        let scrollViewMaxHeight = scrollView.frame.height + headerSize
        return scrollView.contentSize.height > scrollViewMaxHeight
    }

      if isScrollingDown {
            currentScrollingDirection = ScrollingDirection.down
            self.navigationController?.setNavigationBarHidden(true, animated: true)
        } else if isScrollingUp {
            currentScrollingDirection = ScrollingDirection.up
        }

        if scrollView.contentOffset.y <= 20 {
            self.navigationController?.setNavigationBarHidden(false, animated: true)
        }


        if canAnimateHeader(scrollView) {
            self.previousScrollOffset = scrollView.contentOffset.y


            // Dont do anything if were not above a certain height and we are scrolling up
            if scrollView.contentOffset.y >= 120 && currentScrollingDirection == ScrollingDirection.up {
                return
            }

            // Calculate new header height
            let newHeight = self.getNewConstraintValue(constraint: self.extendedNavBarHeightConstraint, valueMin: self.minHeaderHeight, valueMax: self.maxHeaderHeight, scrollDiff: scrollDiff)
            
            // Header needs to animate
            if newHeight != self.extendedNavBarHeightConstraint.constant {
                self.extendedNavBarHeightConstraint.constant = newHeight
                self.setScrollPosition(self.previousScrollOffset)
            }
            
            self.emailLabelWidthConstraint.constant = self.getNewConstraintValue(constraint: self.emailLabelWidthConstraint, valueMin: self.minEmailWidth, valueMax: self.maxEmailWidth, scrollDiff: scrollDiff)
            self.emailLabelHeightConstraint.constant = self.getNewConstraintValue(constraint: self.emailLabelHeightConstraint, valueMin: self.minEmailHeight, valueMax: self.maxEmailHeight, scrollDiff: scrollDiff)
            self.imageViewWidthConstraint.constant = self.getNewConstraintValue(constraint: self.imageViewWidthConstraint, valueMin: self.minImageViewWidth, valueMax: self.maxImageViewWidth, scrollDiff: scrollDiff)
            self.imageViewHeightConstraint.constant = self.getNewConstraintValue(constraint: self.imageViewHeightConstraint, valueMin: self.minImageViewHeight, valueMax: self.maxImageViewHeight, scrollDiff: scrollDiff)
            self.supportTopConstraint.constant = self.getNewConstraintValue(constraint: self.supportTopConstraint, valueMin: self.minSupportTop, valueMax: self.maxSupportTop, scrollDiff: scrollDiff)
            self.emailTopConstraint.constant = self.getNewConstraintValue(constraint: self.emailTopConstraint, valueMin: self.minEmailTop, valueMax: self.maxEmailTop, scrollDiff: scrollDiff)
        }

    func getNewConstraintValue(constraint: NSLayoutConstraint, valueMin: CGFloat, valueMax: CGFloat, scrollDiff: CGFloat) -> CGFloat {
        switch currentScrollingDirection {
        case .down:
            return max(valueMin, constraint.constant - abs(scrollDiff))
        case .up:
            return min(valueMax, constraint.constant + abs(scrollDiff))
        case .none:
            return constraint.constant
        }
    }