efremidze

import UIKit

class RadialGradientLayer: CALayer {
    var colors = [CGColor]() { didSet { setNeedsDisplay() } }
    var locations: [CGFloat]?
    override func draw(in ctx: CGContext) {
        ctx.saveGState()
        guard let gradient = CGGradient(colorsSpace: nil, colors: colors as CFArray, locations: locations) else { return }
        let center = CGPoint(x: bounds.width / 2, y: bounds.height / 2)
        ctx.drawRadialGradient(gradient, startCenter: center, startRadius: 0, endCenter: center, endRadius: radius, options: .drawsBeforeStartLocation)

efremidze

extension UserDefaults {
    func set(forEvery: Int, for key: String, onChange: () -> Void) {
        let count = integer(forKey: key) % forEvery
        if count == 0 { onChange() }
        set(count + 1, forKey: key)
    }
}

efremidze

import ObjectiveC.runtime

// https://codelle.com/blog/2016/2/calling-methods-from-strings-in-swift/
func extractMethod(_ owner: AnyObject, _ selector: Selector) -> ((Any?, Any?) -> AnyObject)? {
    guard let method = getMethod(owner, selector) else { return nil }
    let imp = method_getImplementation(method)
    typealias CFunction = @convention(c) (AnyObject, Selector, Any?, Any?) -> Unmanaged<AnyObject>
    let function = unsafeBitCast(imp, to: CFunction.self)
    return { arg1, arg2 in function(owner, selector, arg1, arg2).takeUnretainedValue() }
}

efremidze

extension UIView {
    func toType<T: UIView>(of type: T.Type) -> T {
        guard let value = self as? T else {
            fatalError("Cannot convert value of type `\(type(of: self))` to expected type `\(type)`")
        }
        return value
    }
}

efremidze

extension UILayoutPriority {
  static func +(lhs: UILayoutPriority, rhs: Float) -> UILayoutPriority {
    return UILayoutPriority(lhs.rawValue + rhs)
  }
  static func -(lhs: UILayoutPriority, rhs: Float) -> UILayoutPriority {
    return UILayoutPriority(lhs.rawValue - rhs)
  }
}

efremidze

extension Comparable {
    func clamped(to limits: ClosedRange<Self>) -> Self {
        return min(max(self, limits.lowerBound), limits.upperBound)
    }
}

efremidze

public class ContainerView<V: UIView>: UIView {

    private var topConstraint: NSLayoutConstraint!
    private var bottomConstraint: NSLayoutConstraint!
    private var leftConstraint: NSLayoutConstraint!
    private var rightConstraint: NSLayoutConstraint!

    /// The view inside the container.
    public let contentView: V

efremidze

extension NSLock {
    func withCriticalScope<T>(block: (Void) -> T) -> T {
        lock()
        let value = block()
        unlock()
        return value
    }
}

efremidze

class Cell: UICollectionViewCell {
    @IBOutlet weak var imageView: UIImageView!
    private static var sharedInstance: Cell!
    static func makeCell(width: CGFloat) -> Cell {
        if sharedInstance == nil {
            sharedInstance = UINib(nibName: String(describing: Cell.self)).instantiate(withOwner: nil, options: nil).first as! Cell
            sharedInstance.constrain { [$0.imageView.widthAnchor.constraint(equalToConstant: width)] }
        }
        return sharedInstance
    }

efremidze

extension Array where Element : Equatable {
    
    mutating func remove(_ element: Element) -> Element? {
        return index(of: element).map { remove(at: $0) }
    }
    
}