CovidData.swift

import Foundation
import FoundationNetworking

var countries = [Country]()

// MARK: - Summary
struct Summary: Codable {
    let global: Global
    let countries: [Country]
    let date: String
    enum CodingKeys: String, CodingKey {
        case global = "Global"
        case countries = "Countries"
        case date = "Date"
    }
}

// MARK: - Country
struct Country: Codable {
    let country, countryCode, slug: String
    let newConfirmed, totalConfirmed, newDeaths, totalDeaths: Int
    let newRecovered, totalRecovered: Int
    let date: String
    enum CodingKeys: String, CodingKey {
        case country = "Country"
        case countryCode = "CountryCode"
        case slug = "Slug"
        case newConfirmed = "NewConfirmed"
        case totalConfirmed = "TotalConfirmed"
        case newDeaths = "NewDeaths"
        case totalDeaths = "TotalDeaths"
        case newRecovered = "NewRecovered"
        case totalRecovered = "TotalRecovered"
        case date = "Date"
    }
}

// MARK: - Global
struct Global: Codable {
    let newConfirmed, totalConfirmed, newDeaths, totalDeaths: Int
    let newRecovered, totalRecovered: Int
    enum CodingKeys: String, CodingKey {
        case newConfirmed = "NewConfirmed"
        case totalConfirmed = "TotalConfirmed"
        case newDeaths = "NewDeaths"
        case totalDeaths = "TotalDeaths"
        case newRecovered = "NewRecovered"
        case totalRecovered = "TotalRecovered"
    }
}

//For local testing on linux (program exits before request callback otherwise)
let semaphore = DispatchSemaphore(value: 0)

let session = URLSession.shared
if let url = URL(string: "https://api.covid19api.com/summary") {
    session.dataTask(with: url) {
        jsonData, response, error in
        if let jsonData = jsonData {
            do {
                let covidSummary = try JSONDecoder().decode(Summary.self, from: jsonData)
                countries = covidSummary.countries

                print(countries)
            }
            catch let error {
                print(error)
            }
            semaphore.signal()
        }
    }.resume()
}

semaphore.wait()