// Roll/Pitch Dynamic Shadow
if motionManager.isDeviceMotionAvailable {
    motionManager.deviceMotionUpdateInterval = 0.02
    motionManager.startDeviceMotionUpdates(to: .main, withHandler: { (motion, error) in
        if let motion = motion {
            let pitch = motion.attitude.pitch * 10 // x-axis
            let roll = motion.attitude.roll * 10 // y-axis
            self.applyShadow(width: CGFloat(roll), height: CGFloat(pitch))
        }
    })
}

// MARK: - Gesture Recognizer
private func configureGestureRecognizer() {
    // Long Press Gesture Recognizer
    longPressGestureRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(handleLongPressGesture(gestureRecognizer:)))
    longPressGestureRecognizer?.minimumPressDuration = 0.1
    addGestureRecognizer(longPressGestureRecognizer!)
}

internal func handleLongPressGesture(gestureRecognizer: UILongPressGestureRecognizer) {
    if gestureRecognizer.state == .began {
        handleLongPressBegan()
    } else if gestureRecognizer.state == .ended || gestureRecognizer.state == .cancelled {
        handleLongPressEnded()
    }
}

private func handleLongPressBegan() {
    guard !isPressed else {
        return
    }

    isPressed = true
    UIView.animate(withDuration: 0.5,
                   delay: 0.0,
                   usingSpringWithDamping: 0.8,
                   initialSpringVelocity: 0.2,
                   options: .beginFromCurrentState,
                   animations: {
                       self.transform = CGAffineTransform(scaleX: 0.95, y: 0.95)
                   }, completion: nil)
}

private func handleLongPressEnded() {
    guard isPressed else {
        return
    }

    UIView.animate(withDuration: 0.5,
                   delay: 0.0,
                   usingSpringWithDamping: 0.4,
                   initialSpringVelocity: 0.2,
                   options: .beginFromCurrentState,
                   animations: {
                       self.transform = CGAffineTransform.identity
                   }) { (finished) in
        self.isPressed = false
    }
}

// MARK: - UICollectionViewDelegateFlowLayout
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    if UIDevice.current.userInterfaceIdiom == .phone {
        return CGSize(width: collectionView.bounds.width, height: BaseRoundedCardCell.cellHeight)
    } else {
        
        // Number of Items per Row
        let numberOfItemsInRow = 2
        
        // Current Row Number
        let rowNumber = indexPath.item/numberOfItemsInRow
        
        // Compressed With
        let compressedWidth = collectionView.bounds.width/3
        
        // Expanded Width
        let expandedWidth = (collectionView.bounds.width/3) * 2
        
        // Is Even Row
        let isEvenRow = rowNumber % 2 == 0
        
        // Is First Item in Row
        let isFirstItem = indexPath.item % numberOfItemsInRow != 0
        
        // Calculate Width
        var width: CGFloat = 0.0
        if isEvenRow {
            width = isFirstItem ? compressedWidth : expandedWidth
        } else {
            width = isFirstItem ? expandedWidth : compressedWidth
        }
        
        return CGSize(width: width, height: BaseRoundedCardCell.cellHeight)
    }
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
    return CGSize(width: collectionView.bounds.width, height: TodaySectionHeader.viewHeight)
}

func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
    let sectionHeader = TodaySectionHeader.dequeue(fromCollectionView: collectionView, ofKind: kind, atIndexPath: indexPath)
    sectionHeader.shouldShowProfileImageView = (indexPath.section == 0)
    return sectionHeader
}