import Foundation


// MARK:- Extensions

let tomiNumber: String = "08080008009"

let car = "toyota"

extension String {

    func addAreaCode() -> String {
        return "+234" + self
    }
}

tomiNumber.addAreaCode()
car.addAreaCode()


// MARK:- Structs VS Classes

final class Humans {
    var name: String

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

extension Humans {
    func eat() -> String {
        return "\(name) is eating"
    }
}

class Person {
    var name: String

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

struct AnotherPerson {
    var name: String
}

// Adress system is called a pointer
let personA = Person(name: "James") // XYZ
let personB = personA //  XYZ
let personC = personB //  XYZ

personA.name
personB.name
personC.name

personC.name = "James Bond"

personA.name
personB.name
personC.name

let personD = Person(name: "Tomi") // LMN
let personE = personD // LMN


var another = AnotherPerson(name: "Luke") // ABC
var anotherB = another // New address

print(another.name)
print(anotherB.name)

anotherB.name = "Luke Skywalker"

print(another.name)
print(anotherB.name)

// MARK:- Type Casting
var arrayOfStuff: [Any] = ["tomi", 3, 4.0]

// Type cast - Force or Make a type to take up alternate behaviour

let number = arrayOfStuff[1] // Any

if let anyNumberAsInteger = number as? Int { // Cast from Any to Int {
    let convertedInteger = String(anyNumberAsInteger)
    print(convertedInteger)
}

if let anyNumberAsString = arrayOfStuff[0] as? String { // Cast from Any to String {
    print(anyNumberAsString)
}

// MARK:- Loops and String Interpolation

// String is collection

let greetingArray = ["how", "are", "you", "?"] // how are you ?

var greeting = ""

// For each
// Map or Compact map

for value in greetingArray {
    greeting = greeting + value
    greeting = greeting + " "
}

print(greeting)

// MARK:- Getters and Setters

class Circle {

    var diameter: Int

    var radius: Int {
        get { return calculateRadius() } // --- Fourth
        set { diameter = newValue * 2  } // --- First

        // willSet { print("I just calulated area of this shape to be \(newValue)") } // Second
        // didSet { print("I just calulated area of this shape") } // Third

    }

    init(diameter: Int) {
        self.diameter = diameter
    }

    func calculateRadius() -> Int {
        return diameter/2
    }
}

var shape = Circle(diameter: 40)

shape.radius = 100

print(shape.diameter)


// MARK:- Optionals

// String?, Int?, Double?, Bool?

// Unwrapping - Safely use those data types

// if let
// guard let
// Nil coalescing

let name: String? = nil

if let unwrappedName = name {
    print(unwrappedName)
} else {
    print("do something if name is nil i.e if it does not have a value")
}

func addition() {
    guard let unwrappedName = name else {
        print("function has exited")
        return
    }
    print(unwrappedName)
}


addition()

print(name ?? "Unidentified")