UIView++.swift

//
//  UIView++.swift
//  FMSwipify
//
//  Created by Franck-Stephane Ndame Mpouli on 12/09/2019.
//

import UIKit

class GradientView: UIView {
    fileprivate let gradientLayer = CAGradientLayer()
    
    override func awakeFromNib() { redraw() }
    open func redraw() {
        gradientLayer.frame = frame
        //        gradientLayer.colors = [UIColor.gradientStart.cgColor, UIColor.gradientEnd.cgColor]
        gradientLayer.startPoint = CGPoint(x: -0.5, y: 0.2)
        gradientLayer.endPoint = CGPoint(x: 1, y: 0.5)
        //        theme_alpha = [1,0]
        layer.addSublayer(gradientLayer)
    }
}

public struct AnchoredConstraints {
    var top, leading, bottom, trailing, width, height: NSLayoutConstraint?
}

public func createObject<T>(_ setup: ((T) -> Void)) -> T where T: NSObject {
    let object = T()
    setup(object)
    return object
}

extension UIView {
    
    func applyGradient(colours: [UIColor]) -> Void {
        let gradient: CAGradientLayer = CAGradientLayer()
        gradient.frame = self.bounds
        gradient.colors = colours.map { $0.cgColor }
        gradient.startPoint = CGPoint(x: -0.5, y: 0.2)
        gradient.endPoint = CGPoint(x: 1, y: 0.5)
        self.layer.insertSublayer(gradient, at: 0)
    }
}



extension UIView {
    
    @available(iOS 9.0, *)
    @discardableResult
    public func anchor(superView: UIView? = nil, top: NSLayoutYAxisAnchor? = nil, leading: NSLayoutXAxisAnchor? = nil, bottom: NSLayoutYAxisAnchor? = nil, trailing: NSLayoutXAxisAnchor? = nil, padding: UIEdgeInsets = .zero, size: CGSize = .zero) -> AnchoredConstraints {
        if let superView = superView {
            superView.addSubview(self)
        }
        translatesAutoresizingMaskIntoConstraints = false
        var anchoredConstraints = AnchoredConstraints()
        
        if let top = top {
            anchoredConstraints.top = topAnchor.constraint(equalTo: top, constant: padding.top)
        }
        
        if let leading = leading {
            anchoredConstraints.leading = leadingAnchor.constraint(equalTo: leading, constant: padding.left)
        }
        
        if let bottom = bottom {
            anchoredConstraints.bottom = bottomAnchor.constraint(equalTo: bottom, constant: -padding.bottom)
        }
        
        if let trailing = trailing {
            anchoredConstraints.trailing = trailingAnchor.constraint(equalTo: trailing, constant: -padding.right)
        }
        
        if size.width != 0 {
            anchoredConstraints.width = widthAnchor.constraint(equalToConstant: size.width)
        }
        
        if size.height != 0 {
            anchoredConstraints.height = heightAnchor.constraint(equalToConstant: size.height)
        }
        
        [anchoredConstraints.top, anchoredConstraints.leading, anchoredConstraints.bottom, anchoredConstraints.trailing, anchoredConstraints.width, anchoredConstraints.height].forEach { $0?.isActive = true }
        
        return anchoredConstraints
    }
    
    @available(iOS 9.0, *)
    public func fillSuperview(padding: UIEdgeInsets = .zero) {
        translatesAutoresizingMaskIntoConstraints = false
        if let superviewTopAnchor = superview?.topAnchor {
            topAnchor.constraint(equalTo: superviewTopAnchor, constant: padding.top).isActive = true
        }
        
        if let superviewBottomAnchor = superview?.bottomAnchor {
            bottomAnchor.constraint(equalTo: superviewBottomAnchor, constant: -padding.bottom).isActive = true
        }
        
        if let superviewLeadingAnchor = superview?.leadingAnchor {
            leadingAnchor.constraint(equalTo: superviewLeadingAnchor, constant: padding.left).isActive = true
        }
        
        if let superviewTrailingAnchor = superview?.trailingAnchor {
            trailingAnchor.constraint(equalTo: superviewTrailingAnchor, constant: -padding.right).isActive = true
        }
    }
    
    @available(iOS 9.0, *)
    public func centerInSuperview(size: CGSize = .zero) {
        translatesAutoresizingMaskIntoConstraints = false
        if let superviewCenterXAnchor = superview?.centerXAnchor {
            centerXAnchor.constraint(equalTo: superviewCenterXAnchor).isActive = true
        }
        
        if let superviewCenterYAnchor = superview?.centerYAnchor {
            centerYAnchor.constraint(equalTo: superviewCenterYAnchor).isActive = true
        }
        
        if size.width != 0 {
            widthAnchor.constraint(equalToConstant: size.width).isActive = true
        }
        
        if size.height != 0 {
            heightAnchor.constraint(equalToConstant: size.height).isActive = true
        }
    }
}