SwiftProtocolConstraintsStarter.swift

//
//  Created by German Velibekov on 11/11/2019.
//  Copyright © 2019 german. All rights reserved.
//

import UIKit

protocol Fiance {}
protocol PoorGuy {}

class Person {}

class AnyPerson: Person {}
class Bride: Person, Fiance {}
class Groom: Person, PoorGuy {}


protocol Friendly {
    func sayHi(to person: Person)
}

extension Friendly {
    func sayHi(to person: Person) {
        //fiance talks to poor guy
        if let _ = self as? Fiance,
            let _ = person as? PoorGuy {
            print("Hey, German. Why so sad?")
        }
        //poor guy talks to fiance
        else if let _ = self as? PoorGuy,
            let _ = person as? Fiance {
            print("Hi, Dana! I'm still using if-elses. That's why 😔")
        }
        else {
            print("Hi")
        }
    }
}

extension Person: Friendly {}

let anyPerson = AnyPerson()
let happyBride = Bride()
let missingGroom = Groom()

missingGroom.sayHi(to: anyPerson)
happyBride.sayHi(to: anyPerson)

happyBride.sayHi(to: missingGroom)
missingGroom.sayHi(to: happyBride)