/*
 * Deskflow -- mouse and keyboard sharing utility
 * SPDX-FileCopyrightText: (C) 2025 Deskflow Developers
 * SPDX-FileCopyrightText: (C) 2012 - 2016 Symless Ltd.
 * SPDX-FileCopyrightText: (C) 2002 Chris Schoeneman
 * SPDX-License-Identifier: GPL-2.0-only WITH LicenseRef-OpenSSL-Exception
 */

#pragma once

#include <cstdint>
#include <string>
#include <vector>

class ArchThreadImpl;
using ArchThread = ArchThreadImpl *;

/*!
\class ArchSocketImpl
\brief Internal socket data.
An architecture dependent type holding the necessary data for a socket.
*/
class ArchSocketImpl;

/*!
\var ArchSocket
\brief Opaque socket type.
An opaque type representing a socket.
*/
using ArchSocket = ArchSocketImpl *;

/*!
\class ArchNetAddressImpl
\brief Internal network address data.
An architecture dependent type holding the necessary data for a network
address.
*/
class ArchNetAddressImpl;

/*!
\var ArchNetAddress
\brief Opaque network address type.
An opaque type representing a network address.
*/
using ArchNetAddress = ArchNetAddressImpl *;

//! Interface for architecture dependent networking
/*!
This interface defines the networking operations required by
deskflow.  Each architecture must implement this interface.
*/
class IArchNetwork
{
public:
  virtual ~IArchNetwork() = default;
  //! Supported address families
  enum class AddressFamily : uint8_t
  {
    Unknown,
    INet,
    INet6
  };

  //! Supported socket types
  enum class SocketType : uint8_t
  {
    DataGram,
    Stream
  };

  //! Events for \c poll()
  /*!
  Events for \c poll() are bitmasks and can be combined using the
  bitwise operators.
  */
  struct PollEventMask
  {
    inline static const int In = 1;      //!< Socket is readable
    inline static const int Out = 2;     //!< Socket is writable
    inline static const int Error = 4;   //!< The socket is in an error state
    inline static const int Invalid = 8; //!< The socket is invalid
  };

  //! A socket query for \c poll()
  class PollEntry
  {
  public:
    //! The socket to query
    ArchSocket m_socket;

    //! The events to query for
    /*!
    The events to query for can be any combination of PollEventMask::In and PollEventMask::Out.
    */
    unsigned short m_events;

    //! The result events
    unsigned short m_revents;
  };

  //! @name manipulators
  //@{

  //! Create a new socket
  /*!
  The socket is an opaque data type.
  */
  virtual ArchSocket newSocket(AddressFamily, SocketType) = 0;

  //! Copy a socket object
  /*!
  Returns a reference to to socket referred to by \c s.
  */
  virtual ArchSocket copySocket(ArchSocket s) = 0;

  //! Release a socket reference
  /*!
  Deletes the given socket object.  This does not destroy the socket
  the object referred to until there are no remaining references for
  the socket.
  */
  virtual void closeSocket(ArchSocket s) = 0;

  //! Close socket for further reads
  /*!
  Calling this disallows future reads on socket \c s.
  */
  virtual void closeSocketForRead(ArchSocket s) = 0;

  //! Close socket for further writes
  /*!
  Calling this disallows future writes on socket \c s.
  */
  virtual void closeSocketForWrite(ArchSocket s) = 0;

  //! Bind socket to address
  /*!
  Binds socket \c s to the address \c addr.
  */
  virtual void bindSocket(ArchSocket s, ArchNetAddress addr) = 0;

  //! Listen for connections on socket
  /*!
  Causes the socket \c s to begin listening for incoming connections.
  */
  virtual void listenOnSocket(ArchSocket s) = 0;

  //! Accept connection on socket
  /*!
  Accepts a connection on socket \c s, returning a new socket for the
  connection and filling in \c addr with the address of the remote
  end.  \c addr may be nullptr if the remote address isn't required.
  The original socket \c s is unaffected and remains in the listening
  state.  The new socket shares most of the properties of \c s except
  it's not in the listening state and it's connected.  Returns nullptr
  if there are no pending connection requests.
  */
  virtual ArchSocket acceptSocket(ArchSocket s, ArchNetAddress *addr) = 0;

  //! Connect socket
  /*!
  Connects the socket \c s to the remote address \c addr.  Returns
  true if the connection succeed immediately, false if the connection
  is in progress, and throws if the connection failed    immediately.
  If it returns false, \c pollSocket() can be used to wait on the
  socket for writing to detect when the connection finally succeeds
  or fails.
  */
  virtual bool connectSocket(ArchSocket s, ArchNetAddress addr) = 0;

  //! Check socket state
  /*!
  Tests the state of \c num sockets for readability and/or writability.
  Waits up to \c timeout seconds for some socket to become readable
  and/or writable (or indefinitely if \c timeout < 0).  Returns the
  number of sockets that were readable (if readability was being
  queried) or writable (if writablility was being queried) and sets
  the \c m_revents members of the entries.  \c PollEventMask::Error and \c PollEventMask::Invalid
  are set in \c m_revents as appropriate.  If a socket indicates
  \c PollEventMask::Error then \c throwErrorOnSocket() can be used to determine
  the type of error.  Returns 0 immediately regardless of the \c timeout
  if no valid sockets are selected for testing.

  (Cancellation point)
  */
  virtual int pollSocket(PollEntry[], int num, double timeout) = 0;

  //! Unblock thread in pollSocket()
  /*!
  Cause a thread that's in a pollSocket() call to return.  This
  call may return before the thread is unblocked.  If the thread is
  not in a pollSocket() call this call has no effect.
  */
  virtual void unblockPollSocket(ArchThread thread) = 0;

  //! Read data from socket
  /*!
  Read up to \c len bytes from socket \c s in \c buf and return the
  number of bytes read.  The number of bytes can be less than \c len
  if not enough data is available.  Returns 0 if the remote end has
  disconnected and/or there is no more queued received data.
  */
  virtual size_t readSocket(ArchSocket s, void *buf, size_t len) = 0;

  //! Write data from socket
  /*!
  Write up to \c len bytes to socket \c s from \c buf and return the
  number of bytes written.  The number of bytes can be less than
  \c len if the remote end disconnected or the internal buffers fill
  up.
  */
  virtual size_t writeSocket(ArchSocket s, const void *buf, size_t len) = 0;

  //! Check error on socket
  /*!
  If the socket \c s is in an error state then throws an appropriate
  ArchNetworkException exception.
  */
  virtual void throwErrorOnSocket(ArchSocket s) = 0;

  //! Turn Nagle algorithm on or off on socket
  /*!
  Set socket to send messages immediately (true) or to collect small
  messages into one packet (false).  Returns the previous state.
  */
  virtual bool setNoDelayOnSocket(ArchSocket, bool noDelay) = 0;

  //! Turn address reuse on or off on socket
  /*!
  Allows the address this socket is bound to to be reused while in the
  TIME_WAIT state.  Returns the previous state.
  */
  virtual bool setReuseAddrOnSocket(ArchSocket, bool reuse) = 0;

  //! Return local host's name
  virtual std::string getHostName() = 0;

  //! Create an "any" network address
  virtual ArchNetAddress newAnyAddr(AddressFamily) = 0;

  //! Copy a network address
  virtual ArchNetAddress copyAddr(ArchNetAddress) = 0;

  //! Convert a name to a network address
  virtual std::vector<ArchNetAddress> nameToAddr(const std::string &) = 0;

  //! Destroy a network address
  virtual void closeAddr(ArchNetAddress) = 0;

  //! Convert an address to a host name
  virtual std::string addrToName(ArchNetAddress) = 0;

  //! Convert an address to a string
  virtual std::string addrToString(ArchNetAddress) = 0;

  //! Get an address's family
  virtual AddressFamily getAddrFamily(ArchNetAddress) = 0;

  //! Set the port of an address
  virtual void setAddrPort(ArchNetAddress, int port) = 0;

  //! Get the port of an address
  virtual int getAddrPort(ArchNetAddress) = 0;

  //! Test addresses for equality
  virtual bool isEqualAddr(ArchNetAddress, ArchNetAddress) = 0;

  //! Test for the "any" address
  /*!
  Returns true if \c addr is the "any" address.  \c newAnyAddr()
  returns an "any" address.
  */
  virtual bool isAnyAddr(ArchNetAddress addr) = 0;

  //@}

  virtual void init() = 0;

private:
  /**
   * @brief throwError, Used to throw network errors
   */
  [[noreturn]] virtual void throwError(int) const = 0;

  /**
   * @brief throwNameError, Errors related to client names.
   */
  [[noreturn]] virtual void throwNameError(int) const = 0;
};