gistfile1.txt

//
//  Cachable.swift
//  CPCoreLibrary
//
//  Created by Dustin Hoffman on 12/8/16.
//  Copyright © 2016 Classpass. All rights reserved.
//

import Foundation

public protocol Cachable {
    
    associatedtype T
    
    func cache()
    static func remove()
    static var keyForClass: String { get }
}

public extension Cachable where Self: NSObject {
    
    public func cache() {
        let userDefaults = UserDefaults.standard
        let data = NSKeyedArchiver.archivedData(withRootObject: self)
        userDefaults.set(data, forKey:type(of:self).keyForClass)
        userDefaults.synchronize()
    }
    
    static var keyForClass: String {
        let className = String(describing: self)
        return "CPKeyForArchiveClass\(className)"
    }
    
    static var cached: T? {
        let userDefaults = UserDefaults.standard
        let data = userDefaults.object(forKey: self.keyForClass)
        return NSKeyedUnarchiver.unarchiveObject(with: data as! Data) as? T
    }
    
    static func remove() {
        let userDefaults = UserDefaults.standard
        userDefaults.removeObject(forKey: self.keyForClass)
        userDefaults.synchronize()
    }
}

class Foo: NSObject, Cachable {
    typealias T = Foo

    func omfg() {
        print("hi")
    }
    
    func foobar() {
        if let xxx = Foo.cached {
            xxx.foobar()
        }
    }
}