UIView+LayoutBridge.swift

UIView+LayoutBridge.swift

//
//  UIView+LayoutBridge.swift
//  IdeasForm
//
//  Created by Roger on 2022/4/1.
//  Copyright © 2022 IdeasForm. All rights reserved.
//

import Foundation
import UIKit

/// A bridge to UIView or UILayoutGuide 's anchor, use `.labr` to fetch instance.
protocol LayoutAnchorBridge {
    
    /// Center X
    var x: NSLayoutXAxisAnchor { get }
    
    /// Center Y
    var y: NSLayoutYAxisAnchor { get }
    
    var width: NSLayoutDimension { get }
    var height: NSLayoutDimension { get }
    var leading: NSLayoutXAxisAnchor { get }
    var trailing: NSLayoutXAxisAnchor { get }
    var top: NSLayoutYAxisAnchor { get }
    var bottom: NSLayoutYAxisAnchor { get }
    
    func done()
    
    // NEXTUP: LayoutAnchorBridge .labr.sup.box()
    // Ignore add superview code
}

// MARK: - Layout methods original define.
extension LayoutAnchorBridge {
    /// Add height and width **constant** constraints to view.
    @discardableResult
    func size(_ width: CGFloat? = nil, _ height: CGFloat? = nil, priority: Float? = nil) -> Self {
        var constraintsToApply: [NSLayoutConstraint] = []
        
        if let width = width {
            constraintsToApply.append(self.width.constraint(equalToConstant: width))
        }
        
        if let height = height {
            constraintsToApply.append(self.height.constraint(equalToConstant: height))
        }
        
        if let priority = priority {
            constraintsToApply.forEach {
                $0.priority = .init(rawValue: priority)
            }
        }
        
        NSLayoutConstraint.activate(constraintsToApply)
        return self
    }
    
    func box(_ layoutGuide: LayoutAnchorBridge, priority: Float? = nil,spacing: CGFloat?...) -> Self {
        assert(spacing.count == 4, "Layout define incomplete, use <nil> represent for undefined constraint.")
        var constraintsToApply: [NSLayoutConstraint] = []
        
        let (vLeading, vTrailing, vTop, vBottom) = (spacing[0], spacing[1], spacing[2], spacing[3])
        
        if let vLeading = vLeading {
            constraintsToApply.append(self.leading.constraint(equalTo: layoutGuide.leading, constant: vLeading))
        }
        
        if let vTrailing = vTrailing {
            constraintsToApply.append(self.trailing.constraint(equalTo: layoutGuide.trailing, constant: -vTrailing))
        }
        
        if let vTop = vTop {
            constraintsToApply.append(self.top.constraint(equalTo: layoutGuide.top, constant: vTop))
        }
        
        if let vBottom = vBottom {
            constraintsToApply.append(self.bottom.constraint(equalTo: layoutGuide.bottom, constant: -vBottom))
        }
        
        if let priority = priority {
            constraintsToApply.forEach { $0.priority = .init(rawValue: priority) }
        }
        
        NSLayoutConstraint.activate(constraintsToApply)
        
        return self
    }
    
    /// Layout for x or y axis position.
    func axis(_ relateView: LayoutAnchorBridge,x xVal: CGFloat? = nil,y yVal: CGFloat? = nil) -> Self {
        
        var constraintsToApply: [NSLayoutConstraint] = []
        
        if let xVal = xVal {
            constraintsToApply.append(self.x.constraint(equalTo: relateView.x, constant: xVal))
        }
        if let yVal = yVal {
            constraintsToApply.append(self.y.constraint(equalTo: relateView.y, constant: yVal))
        }
        
        NSLayoutConstraint.activate(constraintsToApply)
        return self
    }
    
    func above(_ relateView: LayoutAnchorBridge, _ spacing: CGFloat) -> Self {
        NSLayoutConstraint.activate([self.bottom.constraint(equalTo: relateView.top, constant: -spacing)])
        return self
    }
    
    func under(_ relateView: LayoutAnchorBridge, spacing: CGFloat) -> Self {
        NSLayoutConstraint.activate([self.top.constraint(equalTo: relateView.bottom, constant: spacing)])
        return self
    }
    
    func after(_ relateView: LayoutAnchorBridge, spacing: CGFloat) -> Self {
        NSLayoutConstraint.activate([self.leading.constraint(equalTo: relateView.trailing, constant: spacing)])
        return self
    }
    
    func before(_ relateView: LayoutAnchorBridge, spacing: CGFloat) -> Self {
        NSLayoutConstraint.activate([self.trailing.constraint(equalTo: relateView.leading, constant: -spacing)])
        return self
    }
    
    /// Layout suffix to add custom constraints.
    func custom(_ constraints: NSLayoutConstraint...) -> Self {
        NSLayoutConstraint.activate(constraints)
        return self
    }
    
    func custom(_ constraints: [NSLayoutConstraint], priority: Float? = nil) -> Self {
        
        if let priority = priority {
            constraints.forEach { $0.priority = .init(rawValue: priority) }
        }
        
        NSLayoutConstraint.activate(constraints)
        return self
    }
    
    func sameSize(to rhs: LayoutAnchorBridge, h hVal: CGFloat? = nil, w wVal: CGFloat? = nil) -> Self {
        var constraintsToApply: [NSLayoutConstraint] = []
        
        if hVal != nil {
            constraintsToApply.append(self.height.constraint(equalTo: rhs.height, constant: hVal ?? 0))
        }
        if wVal != nil {
            constraintsToApply.append(self.width.constraint(equalTo: rhs.width, constant: wVal ?? 0))
        }

        NSLayoutConstraint.activate(constraintsToApply)
        return self
    }
}

// MARK: - Layout methods reload
extension LayoutAnchorBridge {
    
    /// Add leading, trailing, top, bottom constraint to view, use nil to skip constraint.
    /// - parameters:
    ///     - defines: "leading trailing top bottom" and nil to skip.
    ///     - relateView: always be parameter equalTo
    /// - returns: UIView it self as returned value.
    func box(_ relateView: UIView, priority: Float? = nil, spacing: CGFloat?...) -> Self {
        assert(spacing.count == 4, "Layout define incomplete, use <nil> represent for undefined constraint.")
        return box(relateView.labr, priority: priority, spacing: spacing[0], spacing[1], spacing[2], spacing[3])
    }
    
    func box(_ relateView: UIView, priority: Float? = nil, insets: UIEdgeInsets) -> Self {
        return box(relateView.labr, priority: priority, spacing: insets.left, insets.right, insets.top, insets.bottom)
    }
    
    func box(_ relateView: UILayoutGuide, priority: Float? = nil, spacing: CGFloat?...) -> Self {
        assert(spacing.count == 4, "Layout define incomplete, use <nil> represent for undefined constraint.")
        return box(relateView.labr, priority: priority, spacing: spacing[0], spacing[1], spacing[2], spacing[3])
    }
    
    /// Equal padding box layout bridge
    func box(_ realteView: UIView, padding: CGFloat) -> Self {
        return box(realteView, spacing: padding, padding, padding, padding)
    }
    
    func box(_ realteView: UILayoutGuide, padding: CGFloat) -> Self {
        return box(realteView, spacing: padding, padding, padding, padding)
    }
    
    /// Add leading, trailing, top, bottom constraint to view, use nil to skip constraint.
    /// - parameters:
    ///     - defines: "leading trailing top bottom" and nil to skip.
    ///     - relateView: always be parameter equalTo
    /// - returns: UIView it self as returned value.
    func box(_ relateView: UILayoutGuide, spacing: CGFloat?...) -> Self {
        assert(spacing.count == 4, "Layout define incomplete, use <nil> represent for undefined constraint.")
        return box(relateView.labr, spacing: spacing[0], spacing[1], spacing[2], spacing[3])
    }
    
    /// Layout for x or y axis position.
    func axis(_ relateView: UIView, x: CGFloat? = nil, y: CGFloat? = nil) -> Self { axis(relateView.labr, x: x, y: y) }
    func axis(_ relateView: UILayoutGuide, x: CGFloat? = nil, y: CGFloat? = nil) -> Self { axis(relateView.labr, x: x, y: y) }
    func above(_ relateView: UIView, _ spacing: CGFloat) -> Self { above(relateView.labr, spacing) }
    func above(_ relateView: UILayoutGuide, _ spacing: CGFloat) -> Self { above(relateView.labr, spacing) }
    func after(_ relateView: UIView, _ spacing: CGFloat) -> Self { after(relateView.labr, spacing: spacing) }
    func after(_ relateView: UILayoutGuide, _ spacing: CGFloat) -> Self { after(relateView.labr, spacing: spacing) }
    func before(_ relateView: UIView, _ spacing: CGFloat) -> Self { before(relateView.labr, spacing: spacing) }
    func before(_ relateView: UILayoutGuide, _ spacing: CGFloat) -> Self { before(relateView.labr, spacing: spacing) }
    func under(_ relateView: UIView, _ spacing: CGFloat) -> Self { under(relateView.labr, spacing: spacing) }
    func under(_ relateView: UILayoutGuide, _ spacing: CGFloat) -> Self { under(relateView.labr, spacing: spacing) }
}


// MARK: - Implement of layout bridge.
extension UIView {
    var labr: LayoutAnchorBridge { return LayoutBridgeUIView(self) }
}

extension UILayoutGuide {
    var labr: LayoutAnchorBridge { return LayoutBridgeUILayoutGuide(self) }
}

class LayoutBridgeUIView: LayoutAnchorBridge {
    
    var x: NSLayoutXAxisAnchor { ownedView.centerXAnchor }
    var y: NSLayoutYAxisAnchor { ownedView.centerYAnchor }
    var width: NSLayoutDimension { ownedView.widthAnchor }
    var height: NSLayoutDimension { ownedView.heightAnchor }
    var leading: NSLayoutXAxisAnchor { ownedView.leadingAnchor }
    var trailing: NSLayoutXAxisAnchor { ownedView.trailingAnchor }
    var top: NSLayoutYAxisAnchor { ownedView.topAnchor }
    var bottom: NSLayoutYAxisAnchor { ownedView.bottomAnchor }
    
    private let ownedView: UIView
    
    init(_ owned: UIView) { self.ownedView = owned }
    
    /// translatesAutoresizingMaskIntoConstraints = false
    func done() {
        if self.ownedView.translatesAutoresizingMaskIntoConstraints {
            self.ownedView.translatesAutoresizingMaskIntoConstraints = false
        }
    }
}

class LayoutBridgeUILayoutGuide: LayoutAnchorBridge {
    var x: NSLayoutXAxisAnchor { ownedView.centerXAnchor }
    var y: NSLayoutYAxisAnchor { ownedView.centerYAnchor }
    var width: NSLayoutDimension { ownedView.widthAnchor }
    var height: NSLayoutDimension { ownedView.heightAnchor }
    var leading: NSLayoutXAxisAnchor { ownedView.leadingAnchor }
    var trailing: NSLayoutXAxisAnchor { ownedView.trailingAnchor }
    var top: NSLayoutYAxisAnchor { ownedView.topAnchor }
    var bottom: NSLayoutYAxisAnchor { ownedView.bottomAnchor }
    
    private let ownedView: UILayoutGuide
    
    init(_ owned: UILayoutGuide) { self.ownedView = owned }
    func done() {}
}