NWsClient.h

#ifndef NDMSPC_WEBSOCKET_CLIENT_H
#define NDMSPC_WEBSOCKET_CLIENT_H
 
#include <libwebsockets.h>
 
#include <string>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <atomic>
#include <queue>
#include <vector>
#include <functional>
 
// // Forward declaration of the global LWS callback function.
// /**
//  * @brief Global callback function for libwebsockets client events.
//  *
//  * Handles various websocket events such as connection, message receipt, errors, etc.
//  *
//  * @param wsi Pointer to the websocket instance.
//  * @param reason Callback reason/event type.
//  * @param user User data pointer.
//  * @param in Input data pointer.
//  * @param len Length of input data.
//  * @return Status code for libwebsockets.
//  */
// static int lws_callback_client_impl(struct lws * wsi, enum lws_callback_reasons reason, void * user, void * in,
//                                     size_t len);
 
namespace Ndmspc {

struct WS_URI {
  std::string fScheme; 
  std::string fHost;   
  int         fPort;   
  std::string fPath;   
};

class NWsClient {
  public:
  static constexpr const char * fgProtocolName = "ndmspc-protocol"; 

  NWsClient(int maxRetries = 5, int retryDelayMs = 1000);

  ~NWsClient();

  bool Connect(const std::string & uriString);

  void Disconnect();

  bool Send(const std::string & message);

  bool IsConnected() const { return fConnected.load(); }

  using OnMessageCallback = std::function<void(const std::string &)>;

  void SetOnMessageCallback(OnMessageCallback callback) { fOnMessageCallback = callback; }

  static WS_URI ParseUri(const std::string & uriString);
 
  // private:
  struct lws_context * fLwsContext;       
  struct lws *         fWsi;              
  std::thread          fLwsServiceThread; 
  int                  fMaxRetries;       
  int                  fRetryDelayMs;     
 
  std::string fHost; 
  int         fPort; 
  std::string fPath; 
 
  std::atomic<bool> fConnected;                 
  std::atomic<bool> fShutdownRequested;         
  std::atomic<bool> fConnectionAttemptComplete; 
 
  std::queue<std::string>    fOutgoingMessageQueue; 
  std::mutex                 fOutgoingMutex;        
  std::vector<unsigned char> fSendBuffer;           
  std::condition_variable    fSendCv;               
 
  OnMessageCallback fOnMessageCallback; 
 
  static lws_protocols fProtocols[]; 
 
  std::mutex              fConnectMutex; 
  std::condition_variable fConnectCv;    


  void LwsServiceLoop();
 
  // /**
  //  * @brief Friend declaration for the global callback function.
  //  */
  // friend int lws_callback_client_impl(struct lws * wsi, enum lws_callback_reasons reason, void * user, void * in,
  //                                       size_t len);
};
 
} // namespace Ndmspc
 
#endif // NDMSPC_WEBSOCKET_CLIENT_H