NetworkManager.swift

//
//  NetworkManager.swift
//  kanban3d-ios
//
//  Created by Furkan Kaplan on 15.12.2019.
//  Copyright © 2019 Furkan Kaplan. All rights reserved.
//
import Foundation

enum RequestType: String {
    case POST = "POST"
    case GET = "GET"
}

class NetworkManager {
 
    static let shared: NetworkManager = NetworkManager()
    
    func request<T: Decodable, T2, T3: Encodable>(selfReferance: T2.Type, model: T.Type?,  type: RequestType, url: String, parameters: T3, completion: @escaping ((_ isSuccess: Bool, _ errorMessage: String?, _ data: T?) -> Void)) {
        let session = URLSession.shared
        var urlRequest: URLRequest = URLRequest(url: URL(string: url)!)
        
        do {
            let encoder = JSONEncoder()
            encoder.dateEncodingStrategy = .iso8601
            urlRequest.httpBody = try encoder.encode(parameters)
        } catch {
            print("Error during json encoding")
        }
        
        urlRequest.httpMethod = RequestType.POST.rawValue
        urlRequest.addValue("application/json", forHTTPHeaderField: "Content-Type")

        let task = session.dataTask(with: urlRequest, completionHandler: { data, response, error in
            // Check the response
            self.printDivider()
            print("Network Request Starts")
            self.printDivider()

            print("File: \(T2.self)")
            print("Model: \(T.self)")
            
            guard let response = response else {
                print("Response is nil")
                self.printDivider()
                return
            }
            
            print("Url: \(response.url!)")
            
            // Check if an error occured
            if let error = error {
                // HERE you can manage the error
                print("Error: \(error.localizedDescription)")
                self.printDivider()
                return
            }
            
            if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 {
                print("Status code: \(httpStatus.statusCode)")
                
                do {
                    let json: ResponseModel<T> = try JSONDecoder().decode(ResponseModel<T>.self, from: data!)
                    print("Error message: \(json.error!.message)")
                    self.printDivider()

                    completion(false, json.error!.message, nil)
                } catch {
                    print("Error during error JSON serialization: \(error.localizedDescription)")
                }
                
                return
            }
            
            // Serialize the data into an object
            do {
                print("Status code: 200")
                print("Data: \(String(data: data!, encoding: .utf8)!)")
                self.printDivider()
                
                let json: ResponseModel<T> = try JSONDecoder().decode(ResponseModel<T>.self, from: data!)
                
                completion(true, nil, json.data)
            } catch {
                print("Error during JSON serialization: \(error.localizedDescription)")
            }
        })
        
        task.resume()
    }
    
    func printDivider() {
        print("############################")
    }
    
}