PurchaseEndpoint.swift

enum PurchaseEndpoint {
    private var baseURL: String { return "https://www.purchase.com" }
    
    case product
    case user
    case shop
    case payment
    case productWith(UUID)
    case userWith(UUID)
    case shopWith(UUID)
    case paymentWith(UUID)
    
    private var fullPath: String {
        var endpoint:String
        switch self {
        case .productWith(let id):
            endpoint = "/product/\(id.uuidString)"
        case .userWith(let id):
            endpoint = "/user/\(id.uuidString)"
        case .shopWith(let id):
            endpoint = "/store/\(id.uuidString)"
        case .paymentWith(let id):
            endpoint = "/payment/\(id.uuidString)"
        default:
            endpoint = "/\(String(describing: self))"
        }
        return baseURL + endpoint
    }
    
    var url: URL {
        guard let url = URL(string: fullPath) else {
            preconditionFailure("The url used in \(PurchaseEndpoint.self) is not valid")
        }
        return url
    }
}