import Foundation

class WebSocketConnector : NSObject {
    
    var didOpenConnection : (()->())?
    var didCloseConnection : (()->())?
    var didReceiveMessage : ((_ message : String)->())?
    var didReceiveData : ((_ message : Data)->())?
    var didReceiveError : ((_ error : Error)->())?

    
    
    var urlSession : URLSession?
    var operationQueue : OperationQueue = OperationQueue()
    var socket : URLSessionWebSocketTask?
    var url: URL!
    
    
    init(withSocketURL url : URL){
        super.init()
        self.url = url
        
    }
    
    deinit {
        print("WebSocketConnector deinit")
    }
    
    private func addListener(){
        
        socket?.receive {[weak self] (result) in
            switch result {
            case .success(let response):
                switch response {
                    
                case .data(let data):
                    print(data)
                    self?.didReceiveData?(data)

                case .string(let message):
                    print(message)
                    self?.didReceiveMessage?(message)
                }
            case .failure(let error):
                self?.didReceiveError?(error)
            }
            self?.addListener()

        }
    }
}

extension WebSocketConnector : WebSocketProtocol {
    
    func establishConnection(){
        urlSession  = URLSession(configuration: .default, delegate: self, delegateQueue: operationQueue)
        socket = urlSession?.webSocketTask(with: url)
        
        socket?.resume()
        addListener()
    }
    
    func disconnect(){
        socket?.cancel(with: .goingAway, reason: nil)
        //urlSession?.finishTasksAndInvalidate()
    }
    
    
    func send(message: String) {
        socket?.send(URLSessionWebSocketTask.Message.string(message)) {[weak self] (error) in
            if let error = error {
                self?.didReceiveError?(error)
            }
        }
    }
    
    func send(data: Data) {
        socket?.send(URLSessionWebSocketTask.Message.data(data)) {[weak self] (error) in
            if let error = error {
                self?.didReceiveError?(error)
            }
        }
    }
    
}

extension WebSocketConnector : URLSessionWebSocketDelegate {
    
    func urlSession(_ session: URLSession, webSocketTask: URLSessionWebSocketTask, didOpenWithProtocol protocol: String?) {
        didOpenConnection?()
    }
    
    func urlSession(_ session: URLSession, webSocketTask: URLSessionWebSocketTask, didCloseWith closeCode: URLSessionWebSocketTask.CloseCode, reason: Data?) {
        urlSession?.invalidateAndCancel()
        didCloseConnection?()
    }
}