ConstraintsSettings

.swift

//
//  ConstraintsSettings.swift
//  Rolique
//
//  Created by Bohdan Savych on 9/29/17.
//  Copyright © 2017 Rolique. All rights reserved.
//

import UIKit

final class ConstraintsSettings {
    fileprivate(set) var left: CGFloat?
    fileprivate(set) var right: CGFloat?
    fileprivate(set) var top: CGFloat?
    fileprivate(set) var bottom: CGFloat?
    fileprivate(set) var centerX: CGFloat?
    fileprivate(set) var centerY: CGFloat?
    fileprivate(set) var width: CGFloat?
    fileprivate(set) var height: CGFloat?
    
    init(left: CGFloat = 0, right: CGFloat = 0, top: CGFloat = 0, bottom: CGFloat = 0) {
        self.left = left
        self.right = right
        self.top = top
        self.bottom = bottom
    }
    
    init(edgeInsets: UIEdgeInsets = .zero) {
        self.left = edgeInsets.left
        self.right = edgeInsets.right
        self.top = edgeInsets.top
        self.bottom = edgeInsets.bottom
    }
    
    init(centerX: CGFloat, centerY: CGFloat, width: CGFloat?, height: CGFloat?) {
        self.centerX = centerX
        self.centerY = centerY
        self.width = width
        self.height = height
    }
    
    init(centerX: CGFloat, top: CGFloat?, bottom: CGFloat?, width: CGFloat?) {
        self.centerX = centerX
        self.top = top
        self.bottom = bottom
        self.width = width
    }
    
    init(centerY: CGFloat, left: CGFloat?, right: CGFloat?, height: CGFloat?) {
        self.centerY = centerY
        self.left = left
        self.right = right
        self.height = height
    }
    
    init(width: CGFloat?, height: CGFloat?, left: CGFloat?, right: CGFloat?, top: CGFloat?, bottom: CGFloat?) {
        assert(left == nil || right == nil || width == nil, "ambigious constraints")
        assert(top == nil || bottom == nil || height == nil, "ambigious constraints")
        
        self.left = left
        self.right = right
        self.top = top
        self.bottom = bottom
        self.width = width
        self.height = height
    }
}

extension UIView {
    func addSubview(_ subview: UIView, with constraintsSettings: ConstraintsSettings) {
        subview.translatesAutoresizingMaskIntoConstraints = false
        addSubview(subview)
        let dict = ["v": subview]
        
        if let bottom = constraintsSettings.bottom {
            addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[v]-" + "\(bottom)" + "-|", options: [], metrics: nil, views: dict))
            
        }
        
        if let top = constraintsSettings.top {
            addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-" + "\(top)" + "-[v]", options: [], metrics: nil, views: dict))
        }
        
        if let right = constraintsSettings.right {
            addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:[v]-" + "\(right)" + "-|", options: [], metrics: nil, views: dict))
            
        }
        
        if let left = constraintsSettings.left {
            addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-" + "\(left)" + "-[v]", options: [], metrics: nil, views: dict))
        }
        
        if let height = constraintsSettings.height {
            addConstraint(NSLayoutConstraint(item: subview, attribute: .height,
                                             relatedBy: .equal, toItem: nil, attribute: .notAnAttribute,
                                             multiplier: 1, constant: height))
        }
        
        if let width = constraintsSettings.width {
            addConstraint(NSLayoutConstraint(item: subview, attribute: .width,
                                             relatedBy: .equal, toItem: nil, attribute: .notAnAttribute,
                                             multiplier: 1, constant: width))
        }
        
        if let centerY = constraintsSettings.centerY {
            addConstraint(NSLayoutConstraint(item: subview, attribute: .centerY,
                                             relatedBy: .equal, toItem: self, attribute: .centerY,
                                             multiplier: 1, constant: centerY))
        }
        
        if let centerX = constraintsSettings.centerX {
            addConstraint(NSLayoutConstraint(item: subview, attribute: .centerX,
                                             relatedBy: .equal, toItem: self, attribute: .centerX,
                                             multiplier: 1, constant: centerX))
        }
    }
}