import Foundation
import UIKit


var str = """
{
"name": "Endeavor",
"abv": 8.9,
"brewery": "Saint Arnold",
"style": "ipa"
}

"""

enum BeerStyle:String,Codable {
    case ipa
    case stout
    case kolsch
}

struct Beer : Codable {
    let name : String
    let brewery : String
    let style : BeerStyle
    let abv : Float

    // Custom Keys for Encoding.
    enum EncodingKeys: String, CodingKey {
        case name = "name-alternative"
        case abv = "alcohol_by_volume"
        case brewery = "brewery_name"
        case style
    }

    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: EncodingKeys.self) // Encoding keys are referenced here
        try container.encode(name, forKey: .name)
        try container.encode(brewery, forKey: .brewery)
        try container.encode(style, forKey: .style)
        try container.encode(abv, forKey: .abv)
    }

}

let jsonData = str.data(using: .utf8)!
let decoder = JSONDecoder() // This uses auto generated CodingKeys
let beer = try! decoder.decode(Beer.self, from: jsonData)

let encoder = JSONEncoder()
let json = try! encoder.encode(beer)
let jsonString = String(data: json, encoding: .utf8)
// json String = {"style":"ipa","alcohol_by_volume":8.8999996185302734,"brewery_name":"Saint Arnold","name-alternative":"Endeavor"}"