preferences.swift

/*******************************************************************************
 * The MIT License (MIT)
 *
 * Copyright (c) 2017 Jean-David Gadina - www.xs-labs.com
 * Original: https://github.com/macmade/user-defaults/blob/master/swift/Preferences.swift
 *
 * Copyright (c) 2017 Andrew Crookston - andrewcrookston.com
 * Contributor: https://gist.github.com/acrookston/f973137b9adbd9bff3589ca2cd1d1cb8
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 ******************************************************************************/

import UIKit

@objc public class Preferences: NSObject {
    @objc public dynamic var lastStart: Date?
    @objc public dynamic var fontName:  String?
    @objc public dynamic var fontSize:  CGFloat = 0

    @objc public static let shared = Preferences()

    override init() {
        super.init()

        guard let path = Bundle.main.path(forResource: "Defaults", ofType: "plist") else { return }
        UserDefaults.standard.register(defaults: NSDictionary(contentsOfFile: path) as? [String: Any] ?? [:] )

        for c in Mirror(reflecting: self).children {
            guard let key = c.label else { continue }
            let cached = UserDefaults.standard.object(forKey: key)
            if !(type(of: self.value(forKey: key)) is Optional<Any>.Type) || cached != nil {
                self.setValue(cached, forKey: key)
            }
            self.addObserver(self, forKeyPath: key, options: .new, context: nil)
        }
    }

    deinit {
        for c in Mirror(reflecting: self).children {
            guard let key = c.label else { continue }
            self.removeObserver(self, forKeyPath: key)
        }
    }

    public override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey: Any ]?, context: UnsafeMutableRawPointer?) {
        var found = false

        for c in Mirror(reflecting: self).children {
            guard let key = c.label else { continue }

            if key == keyPath {
                print("Updating: \(key) to \(change?[NSKeyValueChangeKey.newKey])")
                UserDefaults.standard.set(change?[NSKeyValueChangeKey.newKey], forKey: key)
                found = true
                break
            }
        }

        if found == false {
            super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
        }
    }
}