// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
/**
 * @class   vtkSocket
 * @brief   BSD socket encapsulation.
 *
 * This abstract class encapsulates a BSD socket. It provides an API for
 * basic socket operations.
 */

#ifndef vtkSocket_h
#define vtkSocket_h

#include "vtkCommonSystemModule.h" // For export macro
#include "vtkObject.h"

VTK_ABI_NAMESPACE_BEGIN
class vtkSocketCollection;
class VTKCOMMONSYSTEM_EXPORT vtkSocket : public vtkObject
{
public:
  vtkTypeMacro(vtkSocket, vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  // ----- Status API ----
  /**
   * Check is the socket is alive.
   */
  int GetConnected() { return (this->SocketDescriptor >= 0); }

  /**
   * Close the socket.
   */
  void CloseSocket();

  // ------ Communication API ---
  /**
   * These methods send data over the socket.
   * Returns 1 on success, 0 on error and raises vtkCommand::ErrorEvent.
   */
  int Send(const void* data, int length);

  /**
   * Receive data from the socket.
   * This call blocks until some data is read from the socket.
   * When readFully is set, this call will block until all the
   * requested data is read from the socket.
   * 0 on error, else number of bytes read is returned. On error,
   * vtkCommand::ErrorEvent is raised.
   */
  int Receive(void* data, int length, int readFully = 1);

  /**
   * Provides access to the internal socket descriptor. This is valid only when
   * GetConnected() returns true.
   */
  vtkGetMacro(SocketDescriptor, int);

  /**
   * The address the socket is bound to.
   */
  vtkGetMacro(BoundAddress, std::string);

  /**
   * Selects set of sockets. Returns 0 on timeout, -1 on error.
   * 1 on success. Selected socket's index is returned through
   * selected_index
   */
  static int SelectSockets(
    const int* sockets_to_select, int size, unsigned long msec, int* selected_index);

protected:
  vtkSocket();
  ~vtkSocket() override;

  int SocketDescriptor;

  friend class vtkSocketCollection;

  /**
   * Creates an endpoint for communication and returns the descriptor.
   * -1 indicates error.
   */
  int CreateSocket();

  /**
   * Close the socket.
   */
  void CloseSocket(int socketdescriptor);

  ///@{
  /**
   * Binds socket to a particular port and IPv4 address if specified.
   * `bindAddr` defaults to INADDR_ANY (0.0.0.0) if not specified.
   * Returns 0 on success other -1 is returned.
   */
  int BindSocket(int socketdescriptor, int port, const std::string& bindAddr);
  int BindSocket(int socketdescriptor, int port);
  ///@}

  /**
   * Selects a socket ie. waits for it to change status.
   * Returns 1 on success; 0 on timeout; -1 on error. msec=0 implies
   * no timeout.
   */
  int SelectSocket(int socketdescriptor, unsigned long msec);

  /**
   * Accept a connection on a socket. Returns -1 on error. Otherwise
   * the descriptor of the accepted socket.
   */
  int Accept(int socketdescriptor);

  /**
   * Listen for connections on a socket. Returns 0 on success. -1 on error.
   */
  int Listen(int socketdescriptor);

  /**
   * Connect to a server socket. Returns 0 on success, -1 on error.
   */
  int Connect(int socketdescriptor, const char* hostname, int port);

  /**
   * Returns the port to which the socket is connected.
   * 0 on error.
   */
  int GetPort(int socketdescriptor);

private:
  std::string BoundAddress;

  vtkSocket(const vtkSocket&) = delete;
  void operator=(const vtkSocket&) = delete;
};

VTK_ABI_NAMESPACE_END
#endif
