Http.swift

import Foundation

let BASE_URL = ""

enum HttpMethod: String {
    case get = "GET"
    case post = "POST"
}

protocol HttpObserver: AnyObject {
    func httpUnknownError()
    func http(error: String)
    func http(statusCode: Int, data: Data)
}

struct Http {
    let url: URL
    let body: Data?
    let method: HttpMethod
    let headers: [ String: String ]
    
    init(url: String, body: Data? = nil, method: HttpMethod = HttpMethod.get, headers: [ String: String ] = [:]) {
        guard let url = URL(string: url) else {
            fatalError("URL could not be infered.")
        }
        
        self.url = url
        self.body = body
        self.method = method
        self.headers = headers
    }
}

func request(http: Http, observer: HttpObserver) {
    #if DEBUG
    print("====>>>>")
    print(http.url.absoluteString)
    print("------------")
    #endif
    var urlRequest = URLRequest(url: http.url)
    
    urlRequest.httpBody = http.body
    urlRequest.httpMethod = http.method.rawValue
    urlRequest.allHTTPHeaderFields = http.headers
    
    let task = URLSession.shared.dataTask(with: urlRequest) { (data, urlResponse, error) in
        #if DEBUG
        print("data size: \(data?.count ?? 0)")
        print("error: \(error?.localizedDescription ?? "without error")")
        print("<<<<====")
        #endif
        guard let data = data else {
            observer.httpUnknownError()

            return
        }
        
        if let error = error {
            observer.http(error: error.localizedDescription)

            return
        }
        
        observer.http(statusCode: (urlResponse as! HTTPURLResponse).statusCode, data: data)
    }
    
    task.resume()
}