#ifndef SOCKETS_H
#define SOCKETS_H
/////////////////////////////////////////////////////////////////
// Sockets.h - C++ wrapper for C socket api                    //
// ver 4.0                                                     //
// Jim Fawcett, CSE687 - Object Oriented Design, Spring 2015   //
/////////////////////////////////////////////////////////////////
/*
* ToDo:
* - Fix network byte ordering
* - Now works with loopbacks 127.0.0.1 and ::1 but doesn't work
*   with explicit ip addresses or machine names
* - provide send and recv taking external buffer, perhaps array<T>?
* - write buffered recv which efficiently returns string or line
*   - reads and concatenates everything available into circular buffer
*   - parses out first string or line and moves start of buffer pointer
*   - to begining of next
* - polish Socket, SocketConnecter, SocketListener
*   - complete all the move ctors and assignments
*   - finalize the class interfaces
* - build front end, e.g., Sender and Receiver classes
* - implement message facility: message class, sendMsg and recvMsg
* - Add Manual and Maintenance pages
*/

#ifndef WIN32_LEAN_AND_MEAN  // prevents duplicate includes of core parts of windows.h in winsock2.h
#define WIN32_LEAN_AND_MEAN
#endif

#include <Windows.h>      // Windnows API
#include <winsock2.h>     // Windows sockets, ver 2
#include <WS2tcpip.h>     // support for IPv6 and other things
#include <IPHlpApi.h>     // ip helpers

#include <vector>
#include <string>
#include <atomic>

#pragma warning(disable:4522)
#pragma comment(lib, "Ws2_32.lib")

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"

/////////////////////////////////////////////////////////////////////////////
// SocketSystem class - manages loading and unloading Winsock library

class SocketSystem
{
public:
  SocketSystem();
  ~SocketSystem();
private:
  int iResult;
  WSADATA wsaData;
};

/////////////////////////////////////////////////////////////////////////////
// Socket class
// - used by server for client handling
// - base for SocketConnecter and SocketListener classes

class Socket
{
public:
  enum IpVer { IP4, IP6 };
  using byte = char;
  using Block = std::vector < byte >;

  Socket();
  Socket(::SOCKET);
  Socket(const Socket& s) = delete;
  Socket(Socket&& s);
  operator ::SOCKET() { return std::move(socket_); }
  Socket& operator=(const Socket& s) = delete;
  Socket& operator=(Socket&& s);
  virtual ~Socket();
  void close();

  bool send(const Block& blk);
  Block recv();
  bool sendString(const std::string& str);
  std::string recvString();
  size_t bytesWaiting();
  bool waitForData(size_t timeToWait, size_t timeToCheck);
  bool shutDownSend();
  bool shutDownRecv();
  bool shutDown();

  bool validState() { return socket_ != INVALID_SOCKET; }

protected:
  WSADATA wsaData;
  ::SOCKET socket_;
  struct addrinfo *result = NULL, *ptr = NULL, hints;
  static const int recvbuflen = DEFAULT_BUFLEN;
  char recvbuf[recvbuflen];
  int iResult;
};

/////////////////////////////////////////////////////////////////////////////
// SocketConnecter class
// - supports connecting to a SocketListener

class SocketConnecter : public Socket
{
public:
  SocketConnecter() : Socket() {}
  SocketConnecter(const SocketConnecter& s) = delete;
  SocketConnecter(SocketConnecter&& s);
  SocketConnecter& operator=(const SocketConnecter& s) = delete;
  SocketConnecter& operator=(SocketConnecter& s);
  virtual ~SocketConnecter() {}

  bool connect(const std::string& ip, size_t port);
};

/////////////////////////////////////////////////////////////////////////////
// SocketListener class
// - listens for incoming connections
// - each connection is handled on its own thread

class SocketListener : public Socket
{
public:
  SocketListener(size_t port, IpVer ipv=IP6);
  SocketListener(const SocketListener& s) = delete;
  SocketListener(SocketListener&& s);
  SocketListener& operator=(const SocketListener& s) = delete;
  SocketListener& operator=(SocketListener& s);
  virtual ~SocketListener() {}

  template<typename CallObj>
  bool start(CallObj& co);
  void stop();
private:
  bool bind();
  bool listen();
  Socket accept();
  std::atomic<bool> stop_ = false;
  size_t port_;
};

#endif