//
//  UINavigationItemExt.swift
//  ExtensionKit
//
//  Created by FFIB on 2017/9/14.
//  Copyright © 2017年 FFIB. All rights reserved.
//

import UIKit

enum BarViewPosition {
    case left
    case right
}

class BarView: UIView {
    var position = BarViewPosition.left
    var applied = false
    override init(frame: CGRect) {
        super.init(frame: frame)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    override func layoutSubviews() {
        super.layoutSubviews()
        var view = superview
        if #available(iOS 11.0, *){
            guard !applied else {
                return
            }
            while !(view?.isKind(of: UINavigationBar.self) ?? false), let currentView = view {
                if currentView.isKind(of: UIStackView.self), let superView = currentView.superview{
                    switch position {
                    case .left:
                        for constraint in superView.constraints {
                            if constraint.firstItem?.isKind(of: UILayoutGuide.self) ?? false,
                                constraint.firstAttribute == .trailing {
                                superView.removeConstraint(constraint)
                            }
                        }
                        NSLayoutConstraint.activate([NSLayoutConstraint(item: currentView,
                                                                        attribute: .leading,
                                                                        relatedBy: .equal,
                                                                        toItem: superView,
                                                                        attribute: .leading,
                                                                        multiplier: 1.0,
                                                                        constant: 0)])
                        applied = true
                    case .right:
                        for constraint in superView.constraints {
                            if constraint.firstItem?.isKind(of: UILayoutGuide.self) ?? false,
                                constraint.firstAttribute == .leading {
                                superView.removeConstraint(constraint)
                            }
                        }
                        
                        superView.addConstraint(NSLayoutConstraint(item: currentView,
                                                                   attribute: .trailing,
                                                                   relatedBy: .equal,
                                                                   toItem: superView,
                                                                   attribute: .trailing,
                                                                   multiplier: 1.0,
                                                                   constant: 0))
                        applied = true
                    }
                    break
                }
                view = view?.superview
            }
        }
    }
}

extension UINavigationItem {
    
    public func setLeftBar(fixSpace: CGFloat = 12,item: UIBarButtonItem) {
        if #available(iOS 11.0, *), let customView = item.customView {
            let barView = BarView(frame: customView.bounds)
            barView.addSubview(customView)
            customView.center = barView.center
            barView.position = .left
            barView.x = customView.x + fixSpace
            self.leftBarButtonItem = UIBarButtonItem(customView: barView)
            return
        }
        self.leftBarButtonItems = [UIBarButtonItem(space: fixSpace - 30), item]
    }
    
    public func setLeftBars(fixSpace: CGFloat = 12,
                             buttonSpace: CGFloat,
                             images: [UIImage?],
                             actions: [Selector],
                             target: Any) {
        let customView = UIBarButtonItem(images: images,
                                         btnSpace: buttonSpace,
                                         target: target,
                                         actions: actions)
        setLeftBar(fixSpace: fixSpace, item: customView)
    }
    
    public func setRightBars(fixSpace: CGFloat = 12,
                             buttonSpace: CGFloat,
                             images: [UIImage?],
                             actions: [Selector],
                             target: Any) {
        let customView = UIBarButtonItem(images: images,
                                         btnSpace: buttonSpace,
                                         target: target,
                                         actions: actions)
        setRightBar(fixSpace: fixSpace, item: customView)
    }
    
    public func setRightBar(fixSpace: CGFloat = 12, item: UIBarButtonItem) {
        if #available(iOS 11.0, *), let customView = item.customView {
            let barView = BarView(frame: customView.bounds)
            barView.addSubview(customView)
            customView.center = barView.center
            barView.position = .right
            barView.x = customView.x + fixSpace
            self.rightBarButtonItem = UIBarButtonItem(customView: barView)
            return 
        }
        self.rightBarButtonItems = [UIBarButtonItem(space: fixSpace - 30), item]
    }
}