ErrorHandlingSwift3.swift

//: Playground - noun: a place where people can play

import UIKit

var str = "Hello, playground"
//compiler errors
//domain error
let number: Int? = Int.init("1")

print(number as Any)


//runtime errors
//recoverable errors
//unrecoverable errors

struct Friend {
    let name: String
    let age: String
    let address: String?
}

//associated value
enum FriendError: Error {
    case invalidData(description : String)
    case someError
}

func friend(from dict: [String: String]) throws  -> Friend {
    
    guard let name = dict["name"] else {
        throw FriendError.invalidData(description: "invalinda name")
    }
    
    guard  let age = dict["age"]  else {
        throw FriendError.invalidData(description: "invalinda age")
    }
    
    let address = dict["address"]
    return Friend(name: name, age: age, address: address)
}

func send(message: String, to friend: Friend) {
}

let dict = ["name" : "james",
            "ag" : "23",
            "address" : "15 el pulgare"]

do {
    let myFriend = try friend(from: dict)
    send(message: "test", to: myFriend)
} catch FriendError.invalidData(let description) {
    //inform the user for invalid data
    print(description)
} catch FriendError.someError {
    print(FriendError.someError)
}

//creating a model for  JSON REQUEST

enum ParserError: Error {
    case emptyDictionary
    case invalidKey
}

struct Parser {
    var data: [String : String?]?
    
    func parse() throws {
        
        guard (data?["someKeyValue"]) != nil  else {
            throw ParserError.invalidKey
        }
        guard (data?.keys) != nil else {
            throw ParserError.emptyDictionary
        }
    }
}

let data: [String : String?]? = ["someKeyValue": nil]
let parser = Parser(data: data)

do {
    print("test")
    try parser.parse()
} catch ParserError.invalidKey {
    print(ParserError.invalidKey)
} catch ParserError.emptyDictionary {
    print(ParserError.emptyDictionary)
}