Classes

// CLASSES
// Like structs but with 5 important differences:
// 1) Classes don't come with a memberwise initializer.
// 2) Classes can inherit from other classes.
// 3) A copy of a class points to the same thing as the original.
//      Changing one changes the other.
// 4) They have deinitializers (deinit).
// 5) Mutability: No need to add "mutating" to methods that change vars.

// Create your own init
class Dog {
    var name: String
    var breed: String

    init(name: String, breed: String) {
        self.name = name
        self.breed = breed
    }
}

let chico = Dog(name: "Chico", breed: "Boxer Mix")

// INHERITANCE
// Also known as subclassing
// Class you inherit from is the "parent" or "super" class
// New class is the "child" class
// super.init is always called from child's init()
class Poodle: Dog {
    init(name: String) {
        super.init(name: name, breed: "Poodle")
    }
}

// Another example of inheritance
class Handbag {
    var price: Int
    init(price: Int) {
        self.price = price
    }
}
class DesignerHandbag: Handbag {
    var brand: String
    init(brand: String, price: Int) {
        self.brand = brand
        super.init(price: price)
    }
}

let gucci = DesignerHandbag(brand: "Gucci", price: 5)

// OVERRIDING METHODS
class Superhero {
    func superpower() {
        print ("Super strength")
    }
}

class Batman: Superhero {
    override func superpower() {
        print("I'm rich")
    }
}

let superman = Superhero()
superman.superpower()           // "Super strength"
let batman = Batman()
batman.superpower()             // "I'm rich"

// FINAL CLASSES
// Keyword "final" prevents other classes from inheriting from it
// and therefore incapable of overriding your methods
final class Spaceship {
    var name: String

    init(name: String) {
        self.name = name
    }

    func message() {
        print("The name of the ship is \(name)")
    }
}

// class Enterprise: Spaceship {} <--- Returns error message

// COPYING CLASSES
class Singer {
    var name: String

    init(name: String) {
        self.name = name
    }
}

var taylor = Singer(name: "Taylor")
print(taylor.name)          // "Taylor"

var justin = taylor
justin.name = "Justin"
print(justin.name)          // "Justin"
print(taylor.name)          // "Justin"

// DEINITIALIZERS
class EmptyClass {

}

class Soldier {

    var name = "Greg"

    init() {
        print("Hey, my name is \(name) and I'm alive and fighting!")
    }

    func message() {
        print("Just wanted to say hello!")
    }

    deinit {
        print("Now I'm dead... thanks a lot, deinit!")
    }
}

for _ in 1...2 {
    let greg = Soldier()
    greg.message()
}

// MUTABILITY

class Artist {

    var name: String

    init(name: String) {
        self.name = name
    }
}

let joanne = Artist(name: "Joanne")
print(joanne.name)                  // "Joanne"
joanne.name = "Emma"
print(joanne.name)                  // "Emma"
// Doing the above with a struct would not be possible