import UIKit

/*                                THE BASICS S:1
                        (Use ctrl + f 'S:(number)' to find a section)
                                Intro to swift */

var str = "Hello, playground" //variable
let int = 3 //Constant

var x = 3, y = 3, z = 3 //Multiple variable declaration

var testMessage: String //Proper way of setting a type for a variable

//Constants and variables can be pretty much anything except they can't start with numbers...
//Also can't cast into a different type. E.g. String > Integer, like you can in Java.

print(x)
let dog = "Brian" ; print(dog) //Can use semicolons but they are nor required unless using multi line code.


let maxValue = UInt8.max //UInt8 is the 8bit version of the integer value. This is it's maximum value. Don't really need to use this unless required. Should do it automatically.

var unsignedInt :UInt32 ; unsignedInt = 35 //Declares and initializes an unsigned int of 32 bit size.

//Binary/Hexidecimal notation
let decimalInteger = 17
let binaryInteger = 0b10001
let hexadecimalInteger = 0x34

//Exponent
let exponent1 = 34e-2// means sqrt(exponent1)

/*Type conversion*/
//Type conversion can be done on numbers using (type)variable like in java.

//Equivalent of typedef
typealias AudioSample = UInt16

//Tuples
let http404Error = (404, "Not Found")
let http403Error = (403, "Definately not found")
let (statusCode , statusMessage) = http404Error
let (statusCode2, _) = http403Error //Only uses one section of the tuple

//Naming Individual elements at instantiation.
let http402Error = (statuscode3 : 402, statusMessage2 : "So many errors!")

//Optionals...
//ConvertedNumber is technically defined as the optional int? meaning it can either be an int or nothing. Can't be a String for example.
let possibleNumber = "123"
let convertedNumber = Int(possibleNumber)

//Nil is swifts equivalent of null except by default for e.g. defining a String as String? will default it too nil.

if let actualNumber = Int(possibleNumber){
    print("The String \"\(possibleNumber)\" has an integer value of \(actualNumber)")
} else {
    print("The string \"\(possibleNumber)\" could not be converted to an integer")
}

//implicit un-wrapped optionals. Basically use int! instead of int?. Makes damn sure we know exactly what type we are assigning.


/*Error Handling*/

func MakeASandwich() throws {
    //...
}

do {
    try MakeASandwich()
    //
} catch {

}

/*Assertions and Preconditions
 - Assertions (Checked only in debug builds at runtime)
 - Preconditions (Checked in Debug and production builds)
 Really handy way of grabbing errors at runtime and stopping the program if this occours.*/

let age = -3
//assert(age >= 0, "A person's age can't be less than 0.") //This assertion fails because -3 is less than 0.

//If the code is already checked. For example using an if statement we can use 'assertionFailure()' instead.




/*                           BASIC OPERATORS - S:2 */


//Pretty much all the same except Ternary Conditional Operators,


/*      ARRAYS + Multi line String + if/swift statements & while/for loops - 5.3 */
let apples = "apple2.0"

let quotation = """
this is a multi line quotation
which is currently quoting an apple for some reason \(apples)"
""""

var shoppingList = ["milk", "killer bees", "the number 42"]
shoppigList[1] = "bottle of water"

var occupations = ["Malcolm": "Captain", "Nicolas": "Mechanic"]
occuptations["Jayne"] = "public relations"

//Can also use .append, or create an empty array by doing the following
let emptyArray = [String]()
let emptyDictionary = [String: Int]()
inferredList = [] //If type can be inferred

let vegetable = "red pepper"

switch vegetable {
  case "celery":
    print("ew!")
  case "cucumber", "watercress"
    print("slightly better")
  case let x where x.hasSuffix("pepper") //Checks if 'red pepper' has the suffic "pepper"
    print("Is is a spicy \(x)?")
  default:
    print("everything tastes good in soup.")
}

let interestingNumbers = [
    "Prime": [2,3,5,7,11,13],
    "Fibonacci": [1,1,2,3,5,8],
    "Square": [1,4,9,16,25],
]

var largest = 0
for (kind, numbers) in interestingNumbers {
    for number in numbers {
      if number > largest{
        largest = number
      }
    }
}

print(largest)