Swift Class

class Employee {
    let hours: Int

    init(hours: Int) {
        self.hours = hours
    }
    
    func printSummary() {
    print("I work \(hours) hours a day.")
}
}

// Use final to let other developers know how you will be using this class
final class Developer: Employee {
    func work() {
        print("I'm writing code for \(hours) hours.")
    }
    // if a child class wants to change a method from a parent class, you must use override in the child class’s version. This does two things:
    // 1. If you attempt to change a method without using override, Swift will refuse to build your code. This stops you accidentally overriding a method.
    // 2. If you use override but your method doesn’t actually override something from the parent class, Swift will refuse to build your code because you probably made a mistake.
    
    override func printSummary() {
        print("I'm a developer who will sometimes work \(hours) a day, but other times spend hours arguing about whether code should be indented using tabs or spaces.")
    }
}

class Manager: Employee {
    func work() {
        print("I'm going to meetings for \(hours) hours.")
    }
}

let robert = Developer(hours: 8)
let joseph = Manager(hours: 10)
robert.work()
joseph.work()
let novall = Developer(hours: 8)
novall.printSummary()


// Add initialize for classes 
// if a child class has any custom initializers, it must always call the parent’s initializer after it has finished setting up its own properties, if it has any.

class Vehicle {
    let isElectric: Bool

    init(isElectric: Bool) {
        self.isElectric = isElectric
    }
}

class Car: Vehicle {
    let isConvertible: Bool

    init(isElectric: Bool, isConvertible: Bool) {
        self.isConvertible = isConvertible
        super.init(isElectric: isElectric)
    }
}


// Copy Classes

// Reference Copy 
class User {
    var username = "Anonymous"
}
var user1 = User()
var user2 = user1
user2.username = "Taylor"
print(user1.username)  
print(user2.username)

// Deep Copy
class User {
    var username = "Anonymous"

    func copy() -> User {
        let user = User()
        user.username = username
        return user
    }
}

// deinitializer 
class User {
    let id: Int

    init(id: Int) {
        self.id = id
        print("User \(id): I'm alive!")
    }

    deinit {
        print("User \(id): I'm dead!")
    }
}

// All users destroyed in scope
for i in 1...3 {
    let user = User(id: i)
    print("User \(user.id): I'm in control!")
}

// Users saved in larger scope
var users = [User]()

for i in 1...3 {
    let user = User(id: i)
    print("User \(user.id): I'm in control!")
    users.append(user)
}

print("Loop is finished!")
users.removeAll()
print("Array is clear!")

// Variables inside classes, we can change them because the signpost is a constant, but the variable data is a variable
// 1. Constant instance, constant property – a signpost that always points to the same user, who always has the same name.
// 2. Constant instance, variable property – a signpost that always points to the same user, but their name can change.
// 3. Variable instance, constant property – a signpost that can point to different users, but their names never change.
// 4, Variable instance, variable property – a signpost that can point to different users, and those users can also change their names.


// Here we change the variable
class User {
    var name = "Paul"
}

let user = User()
user.name = "Taylor"
print(user.name)

// Here we change the signpost
class User {
    var name = "Paul"
}

var user = User()
user.name = "Taylor"
user = User()
print(user.name)